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Sample records for cortical bone evaluation

  1. Evaluation of trabecular bone patterns on dental radiographic images: influence of cortical bone

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    Amouriq, Yves; Evenou, Pierre; Arlicot, Aurore; Normand, Nicolas; Layrolle, Pierre; Weiss, Pierre; Guédon, Jean-Pierre

    2010-03-01

    For some authors trabecular bone is highly visible in intraoral radiographs. For other authors, the observed intrabony trabecular pattern is a representation of only the endosteal surface of cortical bone, not of intermedullary striae. The purpose of this preliminary study was to investigate the true anatomical structures that are visible in routine dental radiographs and classically denoted trabecular bone. This is a major point for bone texture analysis on radiographs. Computed radiography (CR) images of dog mandible section in molar region were compared with simulations calculated from high-resolution micro-CT volumes. Calculated simulations were obtained using the Mojette Transform. By digitally editing the CT volume, the simulations were separated into trabecular and cortical components into a region of interest. Different images were compared and correlated, some bone micro-architecture parameters calculated. A high correlation was found between computed radiographs and calculated simulations from micro-CT. The Mojette transform was successful to obtain high quality images. Cortical bone did not contribute to change in a major way simulated images. These first results imply that intrabony trabecular pattern observed on radiographs can not only be a representation of the cortical bone endosteal surface and that trabecular bone is highly visible in intraoral radiographs.

  2. Effect of Aging on the Toughness of Human Cortical Bone: Evaluation by R-Curves

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    Kinney, J

    2004-10-08

    Age-related deterioration of the fracture properties of bone, coupled with increased life expectancy, are responsible for increasing incidence of bone fracture in the elderly, and hence, an understanding of how its fracture properties degrade with age is essential. The present study describes ex vivo fracture experiments to quantitatively assess the effect of aging on the fracture toughness properties of human cortical bone in the longitudinal direction. Because cortical bone exhibits rising crack-growth resistance with crack extension, unlike most previous studies the toughness is evaluated in terms of resistance-curve (R-curve) behavior, measured for bone taken from wide range of age groups (34-99 years). Using this approach, both the ex vivo crack-initiation and crack-growth toughness are determined and are found to deteriorate with age; the initiation toughness decreases some 40% over six decades from 40 to 100 years, while the growth toughness is effectively eliminated over the same age range. The reduction in crack-growth toughness is considered to be associated primarily with a degradation in the degree of extrinsic toughening, in particular involving crack bridging in the wake of the crack.

  3. Analysis of cortical bone porosity using synchrotron radiation microtomography to evaluate the effects of chemotherapy

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    Alessio, R.; Nogueira, L. P.; Salata, C.; Mantuano, A.; Almeida, A. P.; Braz, D.; de Almeida, C. E.; Tromba, G.; Barroso, R. C.

    2015-11-01

    Microporosities play important biologic and mechanical roles on health. One of the side effects caused by some chemotherapy drugs is the induction of amenorrhea, temporary or not, in premenopausal women, with a consequent decrease in estrogen production, which can lead to cortical bone changes. In the present work, the femur diaphysis of rats treated with chemotherapy drugs were evaluated by 3D morphometric parameters using synchrotron radiation microtomography. Control animals were also evaluated for comparison. The 3D tomographic images were obtained at the SYRMEP (SYnchrotron Radiation for MEdical Physics) beamline at the ELETTRA Synchrotron Laboratory in Trieste, Italy. Results showed significant differences in morphometric parameters measured from the 3D images of femur diaphysis of rats.

  4. Quantitative radiology: radiogrammetry of cortical bone.

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    Dequeker, J

    1976-11-01

    Based on personal experience and data in the literature, an overview is given of radiogrammetry of cortical bone of the second metacarpal. There is a within- and between-observer error which amounts respectively to 1.2 and 1.5% for the outer diameter and 4.8 and 6.4% for the inner diameter. The systematic + or-- trend between observers indicates that one observer working according to certain defined rules obtains the most reliable results. There is a large variability in amount of bone within one age and sex group which is partly due to skeletal size differences, are insufficient since skeletal size differences still exist. The variability is reduced when the data are divided into strata of skeletal size. Since cortical area shows the best correlation with outer diameter within each age group and since cortical area represents best the ash content of the bones the values of this index are most suited to be grouped according to outer diameter. In differentiating pathological from physiological bone loss this procedure is an improvement on the previously published indices of amount of bone. When comparing different populations this method has advantages since skeletal size differences are eliminated. Comparing seven populations it was found that populations living in the United States of America have more bone for a given skeletal size than populations in Europe or Nigeria. Bone loss with age is a general phenomenon but differences in rate of loss are observed between the sexes and between ethnic different populations. The decrease of bone mass is faster after the age of 50 years in woman than in men. Blacks living in the United States loose less bone with age than whites. Radiogrammetry of cortical bone in groups gives useful information on bond remodelling during ageing and in pathological conditions. At an individual level, however, it is difficult to evaluate changes on a short term basis with radiogrammetry. Radiogrammetry of cortical bone is a simple and

  5. Influence of estrogen deficiency and tibolone therapy on trabecular and cortical bone evaluated by computed radiography system in rats

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    Carvalho, Ana Carolina Bergmann de; Henriques, Helene Nara [Postgraduate Program in Pathology, Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Fernandes, Gustavo Vieira Oliveira [Postgraduate Program in Medical Sciences, Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Lima, Inaya; Oliveira, Davi Ferreira de; Lopes, Ricardo Tadeu [Nuclear Engineering Program, Federal University of Rio de Janeiro (UFRJ), RJ (Brazil); Pantaleao, Jose Augusto Soares [Maternal and Child Department, Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Granjeiro, Jose Mauro [Department of Cellular and Molecular Biology, Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Silva, Maria Angelica Guzman [Department of Pathology, Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil)

    2012-03-15

    Purpose: To verify the effects of tibolone administration on trabecular and cortical bone of ovariectomized female rats by computed radiography system (CRS). Methods: The experiment was performed on two groups of rats previously ovariectomized, one received tibolone (OVX+T) while the other did not (OVX), those groups were compared to a control group (C) not ovariectomized. Tibolone administration (1 mg/day) began thirty days after the ovariectomy and the treatment remained for five months. At last, the animals were euthanized and femurs and tibias collected. Computed radiographs of the bones were obtained and the digital images were used to determine the bone optical density and cortical thickness on every group. All results were statistically evaluated with significance set at P<0.05%. Results: Tibolone administration was shown to be beneficial only in the densitometric analysis of the femoral head, performing higher optical density compared to OVX. No difference was found in cortical bone thickness. Conclusion: Ovariectomy caused bone loss in the analyzed regions and tibolone administered in high doses over a long period showed not to be fully beneficial, but preserved bone mass in the femoral head. (author)

  6. A Retrospective Study on Indian Population to evaluate Cortical Bone Thickness in Maxilla and Mandible using Computed Tomography Images

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    Jeegar Ketan Vakil

    2014-01-01

    Conclusion: Mini-implants have gained considerable popularity due to their low cost, effectiveness, clinical management and stability. Among the factors related to microimplant stability, bone density and cortical bone thickness appear to be critical for successful placement. This study will provide knowledge of cortical bone thickness in various areas which can guide the clinicians in selecting the placement site.

  7. Evaluation of cortical bone thickness of mandible with cone beam computed tomography for orthodontic mini implant installation

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    Seyed Hossein Moslemzade

    2014-07-01

    Full Text Available Background: Achieving maximum anchorage without movement of the teeth in anchorage unit has been a great challenge in orthodontics and the success of the treatment plan highly depends on it. In this case, using orthodontic mini-implants can make a huge difference. The objective of this retrospective study was to measure thickness of cortical bone at prospective mini-implant placement sites in mandible in order to understand stability aspects of mini-implant placement by using cone-beam computed tomography (CBCT images. Materials and Methods: Initial 3-dimensional images of 40 adult patients were studied. The cortical bone thickness was obtained at the alveolar processes from canine to second molar at 5 different vertical levels from the cementoenamel junction (CEJ. To determine the cortical bone thickness, tangent lines were drawn buccolingually to the roots in axial section and a third line was drawn from the middle of these two lines, and the cortical bone thickness was measured where the third line crossed the buccal cortex.   Results: Mandibular and buccal cortical bone thicknesses were 0.79 to 2.49 mm, respectively. There was a statistically significant increase from the CEJ to the apex (P<0.001, while this increase was not statically significant at interdental area of teeth #3 and #4. Comparing the 4 mm section in all sites showed significant increase from anterior to posterior. Conclusion: Based on our results, the cortical bone thickness mostly follows a pattern and depends on the interradicular site rather than individual differences.     Key words: Cone-beam computed tomography; orthodontic anchorage procedures

  8. Cortical bone total ossicular replacement prosthesis

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    Manu Malhotra

    2014-01-01

    Full Text Available Objectives: Evaluate an autologous cortical bone total ossicular replacement prosthesis (B TORP made of cortical bone for cost effective and sustainable hearing results. Materials and Methods: A prospective study was undertaken in the patients who underwent tympanoplasty with new B-TORP from January 2011 to December 2011. All patients had an absent superstructure of the stapes and long process of the incus due to chronic otitis media. Totally 40 patients were evaluated. Hearing results were evaluated using four-frequency average pure tone air conduction and air-bone gap (ABG measured at 0.5, 1, 2, and 3 kHz after a period of 12 months. Pre- and post-operative continuous variables were compared using a paired t-test and data from unequal groups were assessed for significant differences using unpaired t-test. Results: Successful rehabilitation of the ABG to 20 dB or less was achieved in 95% of patients. Overall mean improvement in ABG was 25.8 ± 5.6 dB, which was statistically significant (t = 26.8, P 0.5. Conclusion: The new autologous B-TORP provides sustainable hearing improvement and is bio-compatible, stable, and magnetic resonance imaging compatible.

  9. Swine cortical and cancellous bone: histomorphometric and densitometric characterisation

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    Maria Elena Andreis

    2017-06-01

    Full Text Available Introduction: Swine bone morphology, composition and remodelling are similar to humans’, therefore they are considered good models in bone-related research. They have been used for several studies involving bone growth, bone and cartilage fractures and femoral head osteonecrosis. Nevertheless, the literature about pig normal bone features is incomplete. This work aims to fill the literature gaps on the microarchitecture and Bone Mineral Density (BMD of swine femoral diaphysis and distal epiphysis and tibial plateau and diaphysis. Materials and methods: Five hind limbs were collected from slaughtered 80-100 kg pigs. Microscopic analysis of cortical and cancellous bone from middle/distal femur and proximal/middle tibia was performed to determine basic histomorphometric parameters at different sites. Dual-energy X-Rays Absorptiometry was also employed to evaluate BMD. ANOVA and correlation between BMD, bone area (BA and cortical thickness were performed. Results and discussion: Diaphyseal cortical bone was mostly plexiform both in the tibia and the femur; primary/secondary osteons without clear organization were also found. Mean values for bone area, bone perimeter, trabecular width, number and separation and BMD at different anatomical sites were defined. No significant difference was found for these values at different anatomical sites. BMD proved to be positively correlated with cortical thickness (r=0,80; p<0,01. Despite the small sample size, these results seem homogeneous. They could therefore represent reference values for normal bone parameters in pigs. Applied anatomy and regenerative medicine, in fact, demand very precise information about bone micromorphology, composition and density to provide reliable indication in bone substitutes building. Moreover, since the interpretation of bone abnormalities is based on mastering normal bone characteristics, the definition of reference parameters is mandatory to avoid misinterpretation and

  10. Microstructural parameters of bone evaluated using HR-pQCT correlate with the DXA-derived cortical index and the trabecular bone score in a cohort of randomly selected premenopausal women.

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    Albrecht W Popp

    Full Text Available BACKGROUND: Areal bone mineral density is predictive for fracture risk. Microstructural bone parameters evaluated at the appendicular skeleton by high-resolution peripheral quantitative computed tomography (HR-pQCT display differences between healthy patients and fracture patients. With the simple geometry of the cortex at the distal tibial diaphysis, a cortical index of the tibia combining material and mechanical properties correlated highly with bone strength ex vivo. The trabecular bone score derived from the scan of the lumbar spine by dual-energy X-ray absorptiometry (DXA correlated ex vivo with the micro architectural parameters. It is unknown if these microstructural correlations could be made in healthy premenopausal women. METHODS: Randomly selected women between 20-40 years of age were examined by DXA and HR-pQCT at the standard regions of interest and at customized sub regions to focus on cortical and trabecular parameters of strength separately. For cortical strength, at the distal tibia the volumetric cortical index was calculated directly from HR-pQCT and the areal cortical index was derived from the DXA scan using a Canny threshold-based tool. For trabecular strength, the trabecular bone score was calculated based on the DXA scan of the lumbar spine and was compared with the corresponding parameters derived from the HR-pQCT measurements at radius and tibia. RESULTS: Seventy-two healthy women were included (average age 33.8 years, average BMI 23.2 kg/m(2. The areal cortical index correlated highly with the volumetric cortical index at the distal tibia (R  =  0.798. The trabecular bone score correlated moderately with the microstructural parameters of the trabecular bone. CONCLUSION: This study in randomly selected premenopausal women demonstrated that microstructural parameters of the bone evaluated by HR-pQCT correlated with the DXA derived parameters of skeletal regions containing predominantly cortical or cancellous bone

  11. Microstructural Parameters of Bone Evaluated Using HR-pQCT Correlate with the DXA-Derived Cortical Index and the Trabecular Bone Score in a Cohort of Randomly Selected Premenopausal Women

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    Popp, Albrecht W.; Buffat, Helene; Eberli, Ursula; Lippuner, Kurt; Ernst, Manuela; Richards, R. Geoff; Stadelmann, Vincent A.; Windolf, Markus

    2014-01-01

    Background Areal bone mineral density is predictive for fracture risk. Microstructural bone parameters evaluated at the appendicular skeleton by high-resolution peripheral quantitative computed tomography (HR-pQCT) display differences between healthy patients and fracture patients. With the simple geometry of the cortex at the distal tibial diaphysis, a cortical index of the tibia combining material and mechanical properties correlated highly with bone strength ex vivo. The trabecular bone score derived from the scan of the lumbar spine by dual-energy X-ray absorptiometry (DXA) correlated ex vivo with the micro architectural parameters. It is unknown if these microstructural correlations could be made in healthy premenopausal women. Methods Randomly selected women between 20–40 years of age were examined by DXA and HR-pQCT at the standard regions of interest and at customized sub regions to focus on cortical and trabecular parameters of strength separately. For cortical strength, at the distal tibia the volumetric cortical index was calculated directly from HR-pQCT and the areal cortical index was derived from the DXA scan using a Canny threshold-based tool. For trabecular strength, the trabecular bone score was calculated based on the DXA scan of the lumbar spine and was compared with the corresponding parameters derived from the HR-pQCT measurements at radius and tibia. Results Seventy-two healthy women were included (average age 33.8 years, average BMI 23.2 kg/m2). The areal cortical index correlated highly with the volumetric cortical index at the distal tibia (R  =  0.798). The trabecular bone score correlated moderately with the microstructural parameters of the trabecular bone. Conclusion This study in randomly selected premenopausal women demonstrated that microstructural parameters of the bone evaluated by HR-pQCT correlated with the DXA derived parameters of skeletal regions containing predominantly cortical or cancellous bone. Whether these indexes

  12. Architecture and microstructure of cortical bone in reconstructed canine mandibles after bone transport distraction osteogenesis.

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    Zapata, Uriel; Halvachs, Emily K; Dechow, Paul C; Elsalanty, Mohammed E; Opperman, Lynne A

    2011-11-01

    Reconstruction of the canine mandible using bone transport distraction osteogenesis has been shown to be a suitable method for correcting segmental bone defects produced by cancer, gunshots, and trauma. Although the mechanical quality of the new regenerate cortical bone seems to be related to the mineralization process, several questions regarding the microstructural patterns of the new bony tissue remain unanswered. The purpose of this study was to quantify any microstructural differences that may exist between the regenerate and control cortical bone. Five adult American foxhound dogs underwent unilateral bone transport distraction of the mandible to repair bone defects of 30-35 mm. Animals were killed 12 weeks after the beginning of the consolidation period. Fourteen cylindrical cortical samples were extracted from the superior, medial, and inferior aspects of the lingual and buccal plates of the reconstructed aspect of the mandible, and 21 specimens were collected similarly from the contralateral aspect of the mandible. Specimens were evaluated using histomorphometric and micro-computed tomographic techniques to compare their microstructure. Except for differences in haversian canal area, histomorphometric analyses suggested no statistical differences in microstructure between regenerate and control cortical bone. Morphological evaluation suggested a consistent level of anisotropy, possibly related to the distraction vector. After 12 weeks' consolidation, bone created during bone transport distraction osteogenesis was comparable to native bone in microstructure, architecture, and mechanical properties. It is proposed that, after enough time, the properties of the regenerate bone will be identical to that of native bone.

  13. The use of a 3-dimensional computed tomography bone database to evaluate the risk of distal contact between the rasp tip and the endosteal cortical bone.

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    Connor, Emmalynn; Cowie, Jonathan G; Wuestemann, Thies; Howell, Jonathan R; Whitehouse, Sarah L; Crawford, Ross W

    2016-12-01

    To use a 3-dimensional computed tomography (CT) bone database to evaluate the risk of distal contact between the rasp tip and the endosteal cortical bone. Using a 3-dimensional CT bone database, the rasps for Exeter stems of 125 mm in length and body size 1, with a femoral offset of 37.5, 44, or 50 mm were compared with those for Exeter stems of 150 mm in length and same body size with the corresponding femoral offset. Rasp geometry was determined using an engineering drawing software. Of the 631 femurs in the database, 238 (187 Caucasian and 51 Asian) were of appropriate femoral offset and proximal body size to receive a stem with an offset of 37.5, 44, or 50 mm. Of these, 145 (115 Caucasian and 30 Asian) femurs were of champagne-flute type; the prevalence was comparable between the 2 populations (61% vs. 59%, p=0.729). When using the 150-mm rasp, 70 (55 Caucasian and 15 Asian) of the 238 femurs had distal contact between the rasp and femoral cortex; the prevalence was comparable between the 2 populations (29% vs. 29%, relative risk=1.0, p=1.0). Distal contact between the rasp and femoral cortex occurred more commonly in champagne-flute-type femurs than other femurs in the anteroposterior plane (28% [41/145] vs. 2% [2/93], relative risk=13.1, p<0.001) and in the mediolateral plane (27% [39/145] vs. 14% [13/93], relative risk=1.92, p=0.019). When using the 125-mm rasp, only one femur (with a canal flare index of 4.52) had distal contact in the mediolateral plane with an offset of 37.5 mm. Distal contact between the rasp and femoral cortex occurred more often with the 150-mm rasp than the 125-mm rasp in both planes (p<0.001). The use of a shorter stem may enhance anatomic fit in patients with a narrow femoral canal and prevent distal contact between the rasp and femoral cortex.

  14. Disuse exaggerates the detrimental effects of alcohol on cortical bone

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    Hefferan, Theresa E.; Kennedy, Angela M.; Evans, Glenda L.; Turner, Russell T.

    2003-01-01

    BACKGROUND: Alcohol abuse is associated with an increased risk for osteoporosis. However, comorbidity factors may play an important role in the pathogenesis of alcohol-related bone fractures. Suboptimal mechanical loading of the skeleton, an established risk factor for bone loss, may occur in some alcohol abusers due to reduced physical activity, muscle atrophy, or both. The effect of alcohol consumption and reduced physical activity on bone metabolism has not been well studied. The purpose of this study was to determine whether mechanical disuse alters bone metabolism in a rat model for chronic alcohol abuse. METHODS: Alcohol was administered in the diet (35% caloric intake) of 6-month-old male rats for 4 weeks. Rats were hindlimb-unloaded the final 2 weeks of the experiment to prevent dynamic weight bearing. Afterward, cortical bone histomorphometry was evaluated at the tibia-fibula synostosis. RESULTS: At the periosteal surface of the tibial diaphysis, alcohol and hindlimb unloading independently decreased the mineralizing perimeter, mineral apposition rate, and bone formation rate. In addition, alcohol, but not hindlimb unloading, increased endocortical bone resorption. The respective detrimental effects of alcohol and hindlimb unloading to inhibit bone formation were additive; there was no interaction between the two variables. CONCLUSIONS: Reduced weight bearing accentuates the detrimental effects of alcohol on cortical bone in adult male rats by further inhibiting bone formation. This finding suggests that reduced physical activity may be a comorbidity factor for osteoporosis in alcohol abusers.

  15. Osteocyte lacunar properties in rat cortical bone

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    Bach-Gansmo, Fiona Linnea; Weaver, James C.; Jensen, Mads Hartmann

    2015-01-01

    to osteocyte function, osteocyte lacunar properties such as volume, shape, orientation, and density are now frequently reported in studies investigating osteocyte activity. Despite this increasing interest in lacunar morphometrics, many studies show a large spread in such values, suggesting a large inter......-species but also inter-site variation in lacunar properties. Here, osteocyte lacunae in rat cortical bone have been studied using synchrotron radiation micro computed tomography (SR μCT) and backscattered electron (BE) microscopy. Quantitative lacunar geometric characteristics are reported based on the synchrotron...... radiation data, differentiating between circumferential lamellar bone and a central, more disordered bone type. From these studies, no significant differences were found in lacunar volumes between lamellar and central bone, whereas significant differences in lacunar orientation, shape and density values...

  16. The myokine irisin increases cortical bone mass

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    Colaianni, Graziana; Cuscito, Concetta; Mongelli, Teresa; Pignataro, Paolo; Buccoliero, Cinzia; Liu, Peng; Lu, Ping; Sartini, Loris; Di Comite, Mariasevera; Mori, Giorgio; Di Benedetto, Adriana; Brunetti, Giacomina; Yuen, Tony; Sun, Li; Reseland, Janne E.; Colucci, Silvia; New, Maria I.; Zaidi, Mone; Cinti, Saverio; Grano, Maria

    2015-01-01

    It is unclear how physical activity stimulates new bone synthesis. We explored whether irisin, a newly discovered myokine released upon physical activity, displays anabolic actions on the skeleton. Young male mice were injected with vehicle or recombinant irisin (r-irisin) at a low cumulative weekly dose of 100 µg kg−1. We observed significant increases in cortical bone mass and strength, notably in cortical tissue mineral density, periosteal circumference, polar moment of inertia, and bending strength. This anabolic action was mediated primarily through the stimulation of bone formation, but with parallel notable reductions in osteoclast numbers. The trabecular compartment of the same bones was spared, as were vertebrae from the same mice. Higher irisin doses (3,500 µg kg−1 per week) cause browning of adipose tissue; this was not seen with low-dose r-irisin. Expectedly, low-dose r-irisin modulated the skeletal genes, Opn and Sost, but not Ucp1 or Pparγ expression in white adipose tissue. In bone marrow stromal cell cultures, r-irisin rapidly phosphorylated Erk, and up-regulated Atf4, Runx2, Osx, Lrp5, β-catenin, Alp, and Col1a1; this is consistent with a direct receptor-mediated action to stimulate osteogenesis. We also noted that, although the irisin precursor Fndc5 was expressed abundantly in skeletal muscle, other sites, such as bone and brain, also expressed Fndc5, albeit at low levels. Furthermore, muscle fibers from r-irisin–injected mice displayed enhanced Fndc5 positivity, and irisin induced Fdnc5 mRNA expression in cultured myoblasts. Our data therefore highlight a previously unknown action of the myokine irisin, which may be the molecular entity responsible for muscle–bone connectivity. PMID:26374841

  17. Comparative study between cortical bone graft versus bone dust for reconstruction of cranial burr holes.

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    Worm, Paulo V; Ferreira, Nelson P; Faria, Mario B; Ferreira, Marcelo P; Kraemer, Jorge L; Collares, Marcus V M

    2010-12-22

    As a consequence of the progressive evolution of neurosurgical techniques, there has been increasing concern with the esthetic aspects of burr holes. Therefore, the objective of this study was to compare the use of cortical bone graft and bone dust for correcting cranial deformities caused by neurosurgical trephines. Twenty-three patients were enrolled for cranial burr hole reconstruction with a 1-year follow-up. A total of 108 burr holes were treated; 36 burr holes were reconstructed with autogenous cortical bone discs (33.3%), and the remaining 72 with autogenous wet bone powder (66.6%). A trephine was specifically designed to produce this coin-shaped bone plug of 14 mm in diameter, which fit perfectly over the burr holes. The reconstructions were studied 12 months after the surgical procedure, using three-dimensional quantitative computed tomography. Additionally, general and plastic surgeons blinded for the study evaluated the cosmetic results of those areas, attributing scores from 0 to 10. The mean bone densities were 987.95 ± 186.83 Hounsfield units (HU) for bone fragment and 473.55 ± 220.34 HU for bone dust (P holes because of their lower degree of bone resorption and, consequently, better cosmetic results. The lack of donor site morbidity associated with procedural low cost qualifies the cortical autograft as the first choice for correcting cranial defects created by neurosurgical trephines.

  18. Multiscale and multimodality computed tomography for cortical bone analysis

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    Ostertag, A.; Peyrin, F.; Gouttenoire, P. J.; Laredo, J. D.; DeVernejoul, M. C.; Cohen Solal, M.; Chappard, C.

    2016-12-01

    In clinical studies, high resolution peripheral quantitative computed tomography (HR-pQCT) is used to separately evaluate cortical bone and trabecular bone with an isotropic voxel of 82 µm3, and typical cortical parameters are cortical density (D.comp), thickness (Ct.Th), and porosity (Ct.Po). In vitro, micro-computed tomography (micro-CT) is used to explore the internal cortical bone micro-structure with isotropic voxels and high resolution synchrotron radiation (SR); micro-CT is considered the ‘gold standard’. In 16 tibias and 8 femurs, HR-pQCT measurements were compared to conventional micro-CT measurements. To test modality effects, conventional micro-CT measurements were compared to SR micro-CT measurements at 7.5 µm3 SR micro-CT measurements were also tested at different voxel sizes for the femurs, specifically, 7.5 µm3 versus 2.8 µm3. D.comp (r  =  -0.88, p  images provided consistent results compared to those obtained using conventional micro-CT at the distal tibia. D.comp was highly correlated to Po.V/TV because it considers both the micro-porosity (Haversian systems) and macro-porosity (resorption lacunae) of cortical bone. The complexity of canal organization, (including shape, connectivity, and surface) are not fully considered in conventional micro-CT in relation to beam hardening and cone beam reconstruction artifacts. With the exception of Po.V/TV measurements, morphological and topological measurements depend on the characteristics of the x-ray beam, and to a lesser extent, on image resolution.

  19. Analyzing the anisotropic Hooke's law for children's cortical bone.

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    Lefèvre, Emmanuelle; Lasaygues, Philippe; Baron, Cécile; Payan, Cédric; Launay, Franck; Follet, Hélène; Pithioux, Martine

    2015-09-01

    Child cortical bone tissue is rarely studied because of the difficulty of obtaining samples. Yet the preparation and ultrasonic characterization of the small samples available, while challenging, is one of the most promising ways of obtaining information on the mechanical behavior of non-pathological children׳s bone. We investigated children׳s cortical bone obtained from chirurgical waste. 22 fibula or femur samples from 21 children (1-18 years old, mean age: 9.7±5.8 years old) were compared to 16 fibula samples from 16 elderly patients (50-95 years old, mean age: 76.2±13.5 years old). Stiffness coefficients were evaluated via an ultrasonic method and anisotropy ratios were calculated as the ratio of C33/C11, C33/C22 and C11/C22. Stiffness coefficients were highly correlated with age in children (R>0.56, p0.5), nor between C44 and C55 (p>0.5). We observe a transverse isotropy with C33>C22=C11>C44C55>C66. For both groups, we found no correlation between age and anisotropy ratios. This study offers the first complete analysis of stiffness coefficients in the three orthogonal bone axes in children, giving some indication of how bone anisotropy is related to age. Future perspectives include studying the effect of the structure and composition of bone on its mechanical behavior. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Evaluating mandibular cortical index quantitatively.

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    Yasar, Fusun; Akgunlu, Faruk

    2008-10-01

    The aim was to assess whether Fractal Dimension and Lacunarity analysis can discriminate patients having different mandibular cortical shape. Panoramic radiographs of 52 patients were evaluated for mandibular cortical index. Weighted Kappa between the observations were varying between 0.718-0.805. These radiographs were scanned and converted to binary images. Fractal Dimension and Lacunarity were calculated from the regions where best represents the cortical morphology. It was found that there were statistically significant difference between the Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 1 and Cl 2 (Fractal Dimension P:0.000; Lacunarity P:0.003); and Cl 1 and Cl 3 cortical morphology (Fractal Dimension P:0.008; Lacunarity P:0.001); but there was no statistically significant difference between Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 2 and Cl 3 cortical morphology (Fractal Dimension P:1.000; Lacunarity P:0.758). FD and L can differentiate Cl 1 mandibular cortical shape from both Cl 2 and Cl 3 mandibular cortical shape but cannot differentiate Cl 2 from Cl 3 mandibular cortical shape on panoramic radiographs.

  1. Thermographic stress analysis in cortical bone.

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    Vanderby, R; Kohles, S S

    1991-11-01

    Under adiabatic (or near adiabatic) conditions a volumetric change in an elastic material will produce a corresponding change in temperature. Based upon this principle, thermographic stress analysis (TSA) measures changes in surface heat flux (which are related to changes in surface temperature) and relates them to a coupled form of strains or stresses. To demonstrate the feasibility of using this technique for biomechanical applications, we thermographically measured heat flux from loaded specimens of cortical bone and correlated the results with strain gage data. Regular parallelepipeds were cut from the cortex of bovine femora and loaded sinusoidally at 20 Hz. At this rate of loading, mechanically induced changes in surface temperature could be sampled (via heat flux) prior to a measureable attenuation of the thermoelastic effect. Correlation coefficients demonstrated a significant linear relationship between TSA and measured and computed mechanical parameters (stress, strain, first strain invariant, and strain energy density). TSA therefore appears to be a promising technology for experimental stress analysis in cortical bone.

  2. Impact of lanthanum carbonate on cortical bone in dialysis patients with adynamic bone disease.

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    Yajima, Aiji; Inaba, Masaaki; Tominaga, Yoshihiro; Tanaka, Motoko; Otsubo, Shigeru; Nitta, Kosaku; Ito, Akemi; Satoh, Shigeru

    2013-04-01

    Among the most serious problems in patients with chronic kidney disease (CKD) is fragility of cortical bone caused by cortical thinning and increased cortical porosity; the cortical fragility is sometimes irreversible, with fractures generally initiating from cortical bone. Therefore, development of treatments for problems of cortical bone is urgently desired. Cortical bone has the three surfaces, including the periosteal surface, intracortical spaces and endocortical surface. Bone turnover at the endocortical surface and intracortical resorption spaces are increased as compared with that at cancellous surface. Bone growth sometimes depends on apposition at the periosteal surface. We treated hyperphosphatemia in two hemodialysis patients with adynamic bone disease with 750-1500 mg/day of lanthanum carbonate, which is a non-calcium containing phosphate binder; the treatment resulted in a decrease of the serum phosphorus levels (P levels), without significant change of the serum intact parathyroid hormone levels. We now report that treatment of these patients with lanthanum carbonate increased mineralization of the periosteal surface, increased bone mass within the intracortical resorption spaces and increased mineralization of the minimodeling surface at the endocortical surface. In addition, woven bone volume in cortical bone was decreased and mineralization of bone units, namely, osteons, was increased. Although these findings were not observed across all surfaces of the cortical bone in the patients, it is expected that lanthanum carbonate would increase the cortical stability in CKD patients, with consequent reduction in the fracture rate in these patients.

  3. Demineralized Freeze-Dried Bovine Cortical Bone: Its Potential for Guided Bone Regeneration Membrane

    Directory of Open Access Journals (Sweden)

    David B. Kamadjaja

    2017-01-01

    Full Text Available Background. Bovine pericardium collagen membrane (BPCM had been widely used in guided bone regeneration (GBR whose manufacturing process usually required chemical cross-linking to prolong its biodegradation. However, cross-linking of collagen fibrils was associated with poorer tissue integration and delayed vascular invasion. Objective. This study evaluated the potential of bovine cortical bone collagen membrane for GBR by evaluating its antigenicity potential, cytotoxicity, immune and tissue response, and biodegradation behaviors. Material and Methods. Antigenicity potential of demineralized freeze-dried bovine cortical bone membrane (DFDBCBM was done with histology-based anticellularity evaluation, while cytotoxicity was analyzed using MTT Assay. Evaluation of immune response, tissue response, and biodegradation was done by randomly implanting DFDBCBM and BPCM in rat’s subcutaneous dorsum. Samples were collected at 2, 5, and 7 days and 7, 14, 21, and 28 days for biocompatibility and tissue response-biodegradation study, respectively. Result. DFDBCBM, histologically, showed no retained cells; however, it showed some level of in vitro cytotoxicity. In vivo study exhibited increased immune response to DFDBCBM in early healing phase; however, normal tissue response and degradation rate were observed up to 4 weeks after DFDBCBM implantation. Conclusion. Demineralized freeze-dried bovine cortical bone membrane showed potential for clinical application; however, it needs to be optimized in its biocompatibility to fulfill all requirements for GBR membrane.

  4. Growth hormone effects on cortical bone dimensions in young adults with childhood-onset growth hormone deficiency

    DEFF Research Database (Denmark)

    Hyldstrup, L; Conway, G S; Racz, K

    2012-01-01

    Growth hormone (GH) treatment in young adults with childhood-onset GH deficiency has beneficial effects on bone mass. The present study shows that cortical bone dimensions also benefit from GH treatment, with endosteal expansion and increased cortical thickness leading to improved bone strength....... INTRODUCTION: In young adults with childhood-onset growth hormone deficiency (CO GHD), GH treatment after final height is reached has been shown to have beneficial effects on spine and hip bone mineral density. The objective of the study was to evaluate the influence of GH on cortical bone dimensions. METHODS......: Patients (n = 160; mean age, 21.2 years; 63% males) with CO GHD were randomised 2:1 to GH or no treatment for 24 months. Cortical bone dimensions were evaluated by digital x-ray radiogrammetry of the metacarpal bones every 6 months. RESULTS: After 24 months, cortical thickness was increased compared...

  5. Response of cortical bone to antiresorptive treatment

    DEFF Research Database (Denmark)

    Hyldstrup, Lars; Jørgensen, J T; Sørensen, T K;

    2001-01-01

    A total of 113 postmenopausal women (69 controls, 33 using hormone replacement therapy (HRT), and 11 using bisphosphonate) were evaluated twice over 2 years with a new noninvasive, radiogrammetry-based technique called digital X-ray radiogrammetry (DXR) and conventional bone densitometry of the s...... treatment regimens used in the prevention of osteoporosis....

  6. Computed tomography to evaluate the association of fragmented heterolog cortical bone and methylmethacrylate to repare segmental bone defect produced in tibia of rabbits; Tomografia computadorizada da matriz ossea mineralizada heterologa fragmentada e metilmetacrilato na reparacao de falhas osseas segmentares produzidas em tibia de coelhos

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, S.H. [Universidade Federal de Sao Paulo (USP), SP (Brazil); Doria, R.G.S. [Universidade Federal de Sao Paulo (USP), SP (Brazil). Faculdade de Zootecnia e Engenharia de Alimentos; Mendonca, F.S.; Santos, M.D.; Moreira, R. [Universidade de Cuiaba, MT (Brazil). Faculdade de Medicina Veterinaria; Simoes, R.S. [Universidade Federal de Sao Paulo (USP), SP (Brazil). Hospital Universitario; Camargo, L.M.; Simoes, M.J. [Universidade Federal de Sao Paulo (USP), SP (Brazil). Escola Paulista de Medicina; Marques, A.T.C. [Universidade de Cuiaba, MT (Brazil). Faculdade de Odontologia

    2012-11-15

    A 6mm segmental defect was performed on the metaphyseal region of the tibia of 12 rabbits and the autoclaved fragmented heterolog cortical bone conserved in glycerin (98%) and methylmethacrylate was used as a bone graft for the reconstruction. The graft was placed in the receptor bed and its integration was evaluated by computed tomography after 30, 60 and 90 days. There was gradual bone graft incorporation in the receptor bed during the time in 100% of the cases. Fragmented cortical bone heterograft and methylmethacrylate was biologically compatible and promotes bone defect reparation without signs of infection, migration and or rejection, featuring a new option of osseous substitute to fill in bone defects. (author)

  7. The Effects of Obesity on Murine Cortical Bone

    Science.gov (United States)

    Martin, Sophi

    This dissertation details the effects of obesity on the mechanical properties and structure of cortical bone. Obesity is associated with greater bone mineral content that might be expected to protect against fracture, which has been observed in adults. Paradoxically however, the incidence of bone fractures has been found to increase in overweight and obese children and adolescents. Femora from adolescent and adult mice fed a high-fat diet are investigated for changes in shape, tissue structure, as well as tissue-level and whole-bone mechanical properties. Results indicate increased bone size, reduced size-independent mechanical properties, but maintained size-dependent mechanical properties. Other changes in cortical bone response to obesity are observed with advancing age. This study indicates that bone quantity and bone quality play important compensatory roles in determining fracture risk, and that fracture risk may not be lessened for adults as previously thought.

  8. Lumbar pedicle cortical bone trajectory screw

    Institute of Scientific and Technical Information of China (English)

    Song Tengfei; Wellington K Hsu; Ye Tianwen

    2014-01-01

    Objective The purpose of this study was to demonstrate the lumbar pedicle cortical bone trajectory (CBT) screw fixation technique,a new fixation technique for lumbar surgery.Data sources The data analyzed in this review are mainly from articles reported in PubMed published from 1994 to 2014.Study selection Original articles and critical reviews relevant to CBT technique and lumbar pedicle fixation were selected.Results CBT technique was firstly introduced as a new fixation method for lumbar pedicle surgery in 2009.The concepts,morphometric study,biomechanical characteristics and clinical applications of CBT technique were reviewed.The insertional point of CBT screw is located at the lateral point of the pars interarticularis,and its trajectory follows a caudocephalad path sagittally and a laterally directed path in the transverse plane.CBT technique can be used for posterior fixation during lumbar fusion procedures.This technique is a minimally invasive surgery,which affords better biomechanical stability,fixation strength and surgical safety.Therefore,CBT technique has the greatest benefit in lumbar pedicle surgery for patients with osteoporosis and obesity.Conclusion CBT technique is a better alternative option of lumbar pedicle fixation,especially for patients with osteoporosis and obesity.

  9. An Experimental Study of Radiographic Density of Alveolar Bone and Cortical Thickness of Mandible by Osteoporosis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byeong Do [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Wonkwang University, Iksan (Korea, Republic of)

    2000-12-15

    To evaluate the effect of the systemic osteoporosis on radiographic density of alveolar bone and cortical thickness of mandible. The bone mineral density values of lumbar and femur were measured by dual-energy X-ray absorptiometry and T scores of lumbar, femur were obtained respectively. Radiographic densities of alveolar bones and panorama mandibular index (PMI, represents as cortical thickness) were analysed statistically according to age and T score variavles. The radiographic density of alveolar bone of maxillary molar showed significant difference by age and femur T group. That of mandibular molar showed significant difference between femur T group. Panorama mandibular index showed significant difference between age groups. The radiographic density of alvealar bones was more dependent on age femur T than lumbar T. Cortical thickness of mandible was correlated with increasing age.

  10. Probiotics protect mice from ovariectomy-induced cortical bone loss.

    Science.gov (United States)

    Ohlsson, Claes; Engdahl, Cecilia; Fåk, Frida; Andersson, Annica; Windahl, Sara H; Farman, Helen H; Movérare-Skrtic, Sofia; Islander, Ulrika; Sjögren, Klara

    2014-01-01

    The gut microbiota (GM) modulates the hosts metabolism and immune system. Probiotic bacteria are defined as live microorganisms which when administered in adequate amounts confer a health benefit on the host and can alter the composition of the GM. Germ-free mice have increased bone mass associated with reduced bone resorption indicating that the GM also regulates bone mass. Ovariectomy (ovx) results in bone loss associated with altered immune status. The purpose of this study was to determine if probiotic treatment protects mice from ovx-induced bone loss. Mice were treated with either a single Lactobacillus (L) strain, L. paracasei DSM13434 (L. para) or a mixture of three strains, L. paracasei DSM13434, L. plantarum DSM 15312 and DSM 15313 (L. mix) given in the drinking water during 6 weeks, starting two weeks before ovx. Both the L. para and the L. mix treatment protected mice from ovx-induced cortical bone loss and bone resorption. Cortical bone mineral content was higher in both L. para and L. mix treated ovx mice compared to vehicle (veh) treated ovx mice. Serum levels of the resorption marker C-terminal telopeptides and the urinary fractional excretion of calcium were increased by ovx in the veh treated but not in the L. para or the L. mix treated mice. Probiotic treatment reduced the expression of the two inflammatory cytokines, TNFα and IL-1β, and increased the expression of OPG, a potent inhibitor of osteoclastogenesis, in cortical bone of ovx mice. In addition, ovx decreased the frequency of regulatory T cells in bone marrow of veh treated but not probiotic treated mice. In conclusion, treatment with L. para or the L. mix prevents ovx-induced cortical bone loss. Our findings indicate that these probiotic treatments alter the immune status in bone resulting in attenuated bone resorption in ovx mice.

  11. Probiotics protect mice from ovariectomy-induced cortical bone loss.

    Directory of Open Access Journals (Sweden)

    Claes Ohlsson

    Full Text Available The gut microbiota (GM modulates the hosts metabolism and immune system. Probiotic bacteria are defined as live microorganisms which when administered in adequate amounts confer a health benefit on the host and can alter the composition of the GM. Germ-free mice have increased bone mass associated with reduced bone resorption indicating that the GM also regulates bone mass. Ovariectomy (ovx results in bone loss associated with altered immune status. The purpose of this study was to determine if probiotic treatment protects mice from ovx-induced bone loss. Mice were treated with either a single Lactobacillus (L strain, L. paracasei DSM13434 (L. para or a mixture of three strains, L. paracasei DSM13434, L. plantarum DSM 15312 and DSM 15313 (L. mix given in the drinking water during 6 weeks, starting two weeks before ovx. Both the L. para and the L. mix treatment protected mice from ovx-induced cortical bone loss and bone resorption. Cortical bone mineral content was higher in both L. para and L. mix treated ovx mice compared to vehicle (veh treated ovx mice. Serum levels of the resorption marker C-terminal telopeptides and the urinary fractional excretion of calcium were increased by ovx in the veh treated but not in the L. para or the L. mix treated mice. Probiotic treatment reduced the expression of the two inflammatory cytokines, TNFα and IL-1β, and increased the expression of OPG, a potent inhibitor of osteoclastogenesis, in cortical bone of ovx mice. In addition, ovx decreased the frequency of regulatory T cells in bone marrow of veh treated but not probiotic treated mice. In conclusion, treatment with L. para or the L. mix prevents ovx-induced cortical bone loss. Our findings indicate that these probiotic treatments alter the immune status in bone resulting in attenuated bone resorption in ovx mice.

  12. Buccal cortical bone thickness on CBCT for mini-implant

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Jong Gook; Lim, Sung Hoon; Lee, Byoung Jin; Kim, Jae Duk [School of Dentistry, Chosun University, Gwangju (Korea, Republic of)

    2010-12-15

    Cortical bone thickness is one of the important factor in mini-implant stability. This study was performed to investigate the buccal cortical bone thickness at every interdental area as an aid in planning mini-implant placement. Two-dimensional slices at every interdental area were selected from the cone-beam computed tomography scans of 20 patients in third decade. Buccal cortical bone thickness was measured at 2, 4, and 6 mm levels from the alveolar crest in the interdental bones of posterior regions of both jaws using the plot profile function of Ez3D2009TM (Vatech, Yongin, Korea). The results were analyzed using by Mann-Whitney test. Buccal cortical bone was thicker in the mandible than in the maxilla. The thickness increased with further distance from the alveolar crest in the maxilla and with coming from the posterior to anterior region in the mandible (p?0.01). The maximum CT value showed an increasing tendency with further distance from the alveolar crest and with coming from posterior to anterior region in both jaws. Interdental buccal cortical bone thickness varied in both jaws, however our study showed a distinct tendency. We expect that these results could be helpful for the selection and preparation of mini-implant sites.

  13. Independent measurement of femoral cortical thickness and cortical bone density using clinical CT.

    Science.gov (United States)

    Treece, G M; Gee, A H

    2015-02-01

    The local structure of the proximal femoral cortex is of interest since both fracture risk, and the effects of various interventions aimed at reducing that risk, are associated with cortical properties focused in particular regions rather than dispersed over the whole bone. Much of the femoral cortex is less than 3mm thick, appearing so blurred in clinical CT that its actual density is not apparent in the data, and neither thresholding nor full-width half-maximum techniques are capable of determining its width. Our previous work on cortical bone mapping showed how to produce more accurate estimates of cortical thickness by assuming a fixed value of the cortical density for each hip. However, although cortical density varies much less over the proximal femur than thickness, what little variation there is leads to errors in thickness measurement. In this paper, we develop the cortical bone mapping technique by exploiting local estimates of imaging blur to correct the global density estimate, thus providing a local density estimate as well as more accurate estimates of thickness. We also consider measurement of cortical mass surface density and the density of trabecular bone immediately adjacent to the cortex. Performance is assessed with ex vivo clinical QCT scans of proximal femurs, with true values derived from high resolution HRpQCT scans of the same bones. We demonstrate superior estimation of thickness than is possible with alternative techniques (accuracy 0.12 ± 0.39 mm for cortices in the range 1-3mm), and that local cortical density estimation is feasible for densities >800 mg/cm(3).

  14. Effect of micromorphology of cortical bone tissue on crack propagation under dynamic loading

    Science.gov (United States)

    Wang, Mayao; Gao, Xing; Abdel-Wahab, Adel; Li, Simin; Zimmermann, Elizabeth A.; Riedel, Christoph; Busse, Björn; Silberschmidt, Vadim V.

    2015-09-01

    Structural integrity of bone tissue plays an important role in daily activities of humans. However, traumatic incidents such as sports injuries, collisions and falls can cause bone fracture, servere pain and mobility loss. In addition, ageing and degenerative bone diseases such as osteoporosis can increase the risk of fracture [1]. As a composite-like material, a cortical bone tissue is capable of tolerating moderate fracture/cracks without complete failure. The key to this is its heterogeneously distributed microstructural constituents providing both intrinsic and extrinsic toughening mechanisms. At micro-scale level, cortical bone can be considered as a four-phase composite material consisting of osteons, Haversian canals, cement lines and interstitial matrix. These microstructural constituents can directly affect local distributions of stresses and strains, and, hence, crack initiation and propagation. Therefore, understanding the effect of micromorphology of cortical bone on crack initiation and propagation, especially under dynamic loading regimes is of great importance for fracture risk evaluation. In this study, random microstructures of a cortical bone tissue were modelled with finite elements for four groups: healthy (control), young age, osteoporosis and bisphosphonate-treated, based on osteonal morphometric parameters measured from microscopic images for these groups. The developed models were loaded under the same dynamic loading conditions, representing a direct impact incident, resulting in progressive crack propagation. An extended finite-element method (X-FEM) was implemented to realize solution-dependent crack propagation within the microstructured cortical bone tissues. The obtained simulation results demonstrate significant differences due to micromorphology of cortical bone, in terms of crack propagation characteristics for different groups, with the young group showing highest fracture resistance and the senior group the lowest.

  15. Effect of micromorphology of cortical bone tissue on crack propagation under dynamic loading

    Directory of Open Access Journals (Sweden)

    Wang Mayao

    2015-01-01

    Full Text Available Structural integrity of bone tissue plays an important role in daily activities of humans. However, traumatic incidents such as sports injuries, collisions and falls can cause bone fracture, servere pain and mobility loss. In addition, ageing and degenerative bone diseases such as osteoporosis can increase the risk of fracture [1]. As a composite-like material, a cortical bone tissue is capable of tolerating moderate fracture/cracks without complete failure. The key to this is its heterogeneously distributed microstructural constituents providing both intrinsic and extrinsic toughening mechanisms. At micro-scale level, cortical bone can be considered as a four-phase composite material consisting of osteons, Haversian canals, cement lines and interstitial matrix. These microstructural constituents can directly affect local distributions of stresses and strains, and, hence, crack initiation and propagation. Therefore, understanding the effect of micromorphology of cortical bone on crack initiation and propagation, especially under dynamic loading regimes is of great importance for fracture risk evaluation. In this study, random microstructures of a cortical bone tissue were modelled with finite elements for four groups: healthy (control, young age, osteoporosis and bisphosphonate-treated, based on osteonal morphometric parameters measured from microscopic images for these groups. The developed models were loaded under the same dynamic loading conditions, representing a direct impact incident, resulting in progressive crack propagation. An extended finite-element method (X-FEM was implemented to realize solution-dependent crack propagation within the microstructured cortical bone tissues. The obtained simulation results demonstrate significant differences due to micromorphology of cortical bone, in terms of crack propagation characteristics for different groups, with the young group showing highest fracture resistance and the senior group the

  16. Effect of Cortical Bone Thickness on Detection of Intraosseous Lesions by Ultrasonography

    Directory of Open Access Journals (Sweden)

    Sadaf Adibi

    2015-01-01

    Full Text Available Background. Usefulness of ultrasound (US in detection of intrabony lesions has been showed. A cortical bone perforation or a very thin and intact cortical bone is prerequisite for this purpose. Objective. The current in vitro study was aimed at measuring the cut-off thickness of the overlying cortical bone which allows ultrasonic assessment of bony defects. Materials and Methods. 20 bovine scapula blocks were obtained. Samples were numbered from 1 to 20. In each sample, 5 artificial lesions were made. The lesions were made in order to increase the overlying bone thickness, from 0.1 mm in the first sample to 2 mm in the last one (with 0.1 mm interval. After that, the samples underwent ultrasound examinations by two practicing radiologists. Results. All five lesions in samples numbered 1 to 11 were detected as hypoechoic area. Cortical bone thickness more than 1.1 mm resulted in a failure in the detection of central lesions. Conclusion. We can conclude that neither bony perforation nor very thin cortical bones are needed to consider US to be an effective imaging technique in the evaluation of bony lesion.

  17. Femoral cortical index: an indicator of poor bone quality in patient with hip fracture.

    Science.gov (United States)

    Feola, M; Rao, C; Tempesta, V; Gasbarra, E; Tarantino, U

    2015-10-01

    Osteoporosis is a common disease in elderly, characterized by poor bone quality as a result of alterations affecting trabecular bone. However, recent studies have described also an important role of alterations of cortical bone in the physiopathology of osteoporosis. Although dual-energy X-ray absorptiometry (DXA) is a valid method to assess bone mineral density, in the presence of comorbidities real bone fragility is unable to be evaluated. The number of hip fractures is rising, especially in people over 85 years old. The aim is to evaluate an alternative method so that it can indicate fracture risk, independent of bone mineral density (BMD). Femoral cortical index (FCI) assesses cortical bone stock using femur X-ray. A retrospective study has been conducted on 152 patients with hip fragility fractures. FCI has been calculated on fractured femur and on the opposite side. The presence of comorbidities, osteoporosis risk factors, vitamin D levels, and BMD have been analyzed for each patient. Average values of FCI have been 0.42 for fractured femurs and 0.48 at the opposite side with a statistically significant difference (p = 0.002). Patients with severe hypovitaminosis D had a minor FCI compared to those with moderate deficiency (0.41 vs. 0.46, p hip fractures has been found. FCI could be a useful tool to evaluate bone fragility and to predict fracture risk even in the normal and osteopenic BMD patients.

  18. Strontium Ranelate Effect on the Repair of Bone Defects and Molecular Components of the Cortical Bone of Rats.

    Science.gov (United States)

    Rosa, Jucely Aparecida da; Sakane, Kumiko Koibuchi; Santos, Karina Cecília Panelli; Corrêa, Vivian Bradaschia; Arana-Chavez, Victor Elias; Oliveira, Jefferson Xavier de

    2016-01-01

    This study was conducted to evaluate the effects of treatment with strontium ranelate (SR) on the repair of bone defects and molecular components of bones in femurs. Adult female rats (n=27) were subjected to ovariectomy (OVX) or Sham surgery. Thirty days after surgery, a defect was made in the femur and the animals were then divided into three groups: OVX, SHAM and OVX+SR. Euthanasia was performed four weeks after the bone defect surgery. Repair in bone defect was assessed by computed microtomography (μCT) and chemical composition of cortical bone was analyzed by Fourier transform infrared (FTIR) spectroscopy and energy dispersive X-ray spectroscopy (EDS). The trabecular thickness (Tb.Th) of the newly formed bone in the OVX+SR group was significantly higher than that for the OVX group. The collagen maturity in the OVX+SR group was smaller than in the other two groups. In this group, a significant increase in the amount of strontium (Sr) and a decrease in the amount of calcium (Ca) embedded to bone tissue were also observed. Systemic treatment with SR improved microarchitecture of the newly formed bone inside the defect, but decreased cross-linking of mature collagen in cortical bone.

  19. Regional variability in secondary remodeling within long bone cortices of catarrhine primates: the influence of bone growth history.

    Science.gov (United States)

    McFarlin, Shannon C; Terranova, Carl J; Zihlman, Adrienne L; Enlow, Donald H; Bromage, Timothy G

    2008-09-01

    Secondary intracortical remodeling of bone varies considerably among and within vertebrate skeletons. Although prior research has shed important light on its biomechanical significance, factors accounting for this variability remain poorly understood. We examined regional patterning of secondary osteonal bone in an ontogenetic series of wild-collected primates, at the midshaft femur and humerus of Chlorocebus (Cercopithecus) aethiops (n = 32) and Hylobates lar (n = 28), and the midshaft femur of Pan troglodytes (n = 12). Our major objectives were: 1) to determine whether secondary osteonal bone exhibits significant regional patterning across inner, mid-cortical and outer circumferential cortical rings within cross-sections; and if so, 2) to consider the manner in which this regional patterning may reflect the influence of relative tissue age and other circumstances of bone growth. Using same field-of-view images of 100-microm-thick cross-sections acquired in brightfield and circularly polarized light microscopy, we quantified the percent area of secondary osteonal bone (%HAV) for whole cross-sections and across the three circumferential rings within cross-sections. We expected bone areas with inner and middle rings to exhibit higher %HAV than the outer cortical ring within cross-sections, the latter comprising tissues of more recent depositional history. Observations of primary bone microstructural development provided an additional context in which to evaluate regional patterning of intracortical remodeling. Results demonstrated significant regional variability in %HAV within all skeletal sites. As predicted,%HAV was usually lowest in the outer cortical ring within cross-sections. However, regional patterning across inner vs. mid-cortical rings showed a more variable pattern across taxa, age classes, and skeletal sites examined. Observations of primary bone microstructure revealed that the distribution of endosteally deposited bone had an important influence on

  20. Evaluation of the relationship of mandibular cortical index and panoramic mandibular index with bone mineral density using panoramic radiography in postmenopausal women: A short study

    Directory of Open Access Journals (Sweden)

    Gargi Saran

    2015-01-01

    Full Text Available Introduction: The problems associated with age-related skeletal osteopenia have received attention since the human skeleton undergoes a continuous physiologic decrease in bone mass with advancing age. Bone status at various sites can be assessed using dual-energy X-ray absorptiometry (DXA or quantitative computed tomography. It would be useful to answer whether radiographic changes in the mandible indicate skeletal osteopenia. Aims and Objectives: The aim and objective of the study was to examine the mandibular cortical index (MCI and panoramic mandibular index (PMI on panoramic radiograph and to establish a relationship between the two indices (MCI and PMI with the bone mineral density (BMD in postmenopausal women. Materials and Methods: The study consisted of 15 postmenopausal women within the age group of 45-75 years. BMD was performed by DXA and measured at the lumbar spine and femoral neck and values were recorded. Panoramic radiographs of the same women were obtained for measuring MCI and PMI. There were two groups taken as C1 and C2 for determination of MCI and PMI. Results: The Pearson correlation analysis revealed a significant correlation between age and T-score (r = −0.59, P < 0.05, i.e., as age increased the T-score decreased. Comparing the T-score of two MCI groups, t-test revealed MCI was 69.1% lower in C2 as compared to C1. The value of P < 0.001 and t-test revealed significantly different and lowered (32.4% inferior cortex level in C2 as compared to C1 (t = 4.76, P < 0.001. Conclusion: Results suggest that in this study panoramic radiography could be a reliable tool in screening for BMD.

  1. Insulin Resistance Is Associated With Smaller Cortical Bone Size in Nondiabetic Men at the Age of Peak Bone Mass.

    Science.gov (United States)

    Verroken, Charlotte; Zmierczak, Hans-Georg; Goemaere, Stefan; Kaufman, Jean-Marc; Lapauw, Bruno

    2017-06-01

    In type 2 diabetes mellitus, fracture risk is increased despite preserved areal bone mineral density. Although this apparent paradox may in part be explained by insulin resistance affecting bone structure and/or material properties, few studies have investigated the association between insulin resistance and bone geometry. We aimed to explore this association in a cohort of nondiabetic men at the age of peak bone mass. Nine hundred ninety-six nondiabetic men aged 25 to 45 years were recruited in a cross-sectional, population-based sibling pair study at a university research center. Insulin resistance was evaluated using the homeostasis model assessment of insulin resistance (HOMA-IR), with insulin and glucose measured from fasting serum samples. Bone geometry was assessed using peripheral quantitative computed tomography at the distal radius and the radial and tibial shafts. In age-, height-, and weight-adjusted analyses, HOMA-IR was inversely associated with trabecular area at the distal radius and with cortical area, periosteal and endosteal circumference, and polar strength strain index at the radial and tibial shafts (β ≤ -0.13, P insulin-like growth factor 1, or sex steroid levels. In this cohort of nondiabetic men at the age of peak bone mass, insulin resistance is inversely associated with trabecular and cortical bone size. These associations persist after adjustment for body composition, muscle size or function, or sex steroid levels, suggesting an independent effect of insulin resistance on bone geometry.

  2. Cancellous and cortical bone imaging by reflected tomography.

    Science.gov (United States)

    Lasaygues, P; Lefebvre, J P

    2001-01-01

    This paper deals with the inverse scattering problem observed when ultrasonic waves are used to analyze biological media. The objective is to image cancellous and cortical bone by ultrasonic reflected tomography (URT). Because strong contrast and high absorbance bodies such as bones cannot be imaged at usual ultrasonic high frequencies (> 1 MHz), we adapted for low-frequency URT (Papoulis deconvolution). This resolution enhancement for human porous vertebrae and human and animal femur showed that high-resolution images can be obtained with low-frequency URT.

  3. Histological analysis of the alterations on cortical bone channels network after radiotherapy: A rabbit study.

    Science.gov (United States)

    Rabelo, Gustavo Davi; Beletti, Marcelo Emílio; Dechichi, Paula

    2010-10-01

    The aim of this study was to evaluate the effects of radiotherapy in cortical bone channels network. Fourteen rabbits were divided in two groups and test group received single dose of 15 Gy cobalt-60 radiation in tibia, bilaterally. The animals were sacrificed and a segment of tibia was removed and histologically processed. Histological images were taken and had their bone channels segmented and called regions of interest (ROI). Images were analyzed through developed algorithms using the SCILAB mathematical environment, getting percentage of bone matrix, ROI areas, ROI perimeters, their standard deviations and Lacunarity. The osteocytes and empty lacunae were also counted. Data were evaluated using Kolmogorov-Smirnov, Mann Whitney, and Student's t test (P lacunarity were found between groups. In conclusion, the radiotherapy causes reduction of bone matrix and modifies the morphology of bone channels network. © 2010 Wiley-Liss, Inc.

  4. Calcifying tendinitis of the rotator cuff with cortical bone erosion.

    Science.gov (United States)

    Chan, Roxanne; Kim, David H; Millett, Peter J; Weissman, Barbara N

    2004-10-01

    Calcifying tendinitis occurs most commonly in the rotator cuff tendons, particularly involving the supraspinatus tendon insertion, and is often asymptomatic. Cortical erosion secondary to calcifying tendinitis has been reported in multiple locations, including in the rotator cuff tendons. We present a pathologically proven case of symptomatic calcifying tendinitis involving the infraspinatus tendon with cortical erosion with correlative radiographic, CT, and MR findings. The importance of considering this diagnosis when evaluating lytic lesions of the humerus and the imaging differential diagnosis of calcifying tendinitis and cortical erosion are discussed.

  5. Calcifying tendinitis of the rotator cuff with cortical bone erosion

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Roxanne; Kim, David H.; Millett, Peter J. [Harvard Medical School, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Weissman, Barbara N. [Harvard Medical School, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Brigham and Women' s Hospital, Department of Radiology, Musculoskeletal Division, Boston (United States)

    2004-10-01

    Calcifying tendinitis occurs most commonly in the rotator cuff tendons, particularly involving the supraspinatus tendon insertion, and is often asymptomatic. Cortical erosion secondary to calcifying tendinitis has been reported in multiple locations, including in the rotator cuff tendons. We present a pathologically proven case of symptomatic calcifying tendinitis involving the infraspinatus tendon with cortical erosion with correlative radiographic, CT, and MR findings. The importance of considering this diagnosis when evaluating lytic lesions of the humerus and the imaging differential diagnosis of calcifying tendinitis and cortical erosion are discussed. (orig.)

  6. Genetic algorithms-based inversion of multimode guided waves for cortical bone characterization

    Science.gov (United States)

    Bochud, N.; Vallet, Q.; Bala, Y.; Follet, H.; Minonzio, J.-G.; Laugier, P.

    2016-10-01

    Recent progress in quantitative ultrasound has exploited the multimode waveguide response of long bones. Measurements of the guided modes, along with suitable waveguide modeling, have the potential to infer strength-related factors such as stiffness (mainly determined by cortical porosity) and cortical thickness. However, the development of such model-based approaches is challenging, in particular because of the multiparametric nature of the inverse problem. Current estimation methods in the bone field rely on a number of assumptions for pairing the incomplete experimental data with the theoretical guided modes (e.g. semi-automatic selection and classification of the data). The availability of an alternative inversion scheme that is user-independent is highly desirable. Thus, this paper introduces an efficient inversion method based on genetic algorithms using multimode guided waves, in which the mode-order is kept blind. Prior to its evaluation on bone, our proposal is validated using laboratory-controlled measurements on isotropic plates and bone-mimicking phantoms. The results show that the model parameters (i.e. cortical thickness and porosity) estimated from measurements on a few ex vivo human radii are in good agreement with the reference values derived from x-ray micro-computed tomography. Further, the cortical thickness estimated from in vivo measurements at the third from the distal end of the radius is in good agreement with the values delivered by site-matched high-resolution x-ray peripheral computed tomography.

  7. Automatic Detection of Cortical Bones Haversian Osteonal Boundaries

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    Ilige Hage

    2015-10-01

    Full Text Available This work aims to automatically detect cement lines in decalcified cortical bone sections stained with H&E. Employed is a methodology developed previously by the authors and proven to successfully count and disambiguate the micro-architectural features (namely Haversian canals, canaliculi, and osteocyte lacunae present in the secondary osteons/Haversian system (osteon of cortical bone. This methodology combines methods typically considered separately, namely pulse coupled neural networks (PCNN, particle swarm optimization (PSO, and adaptive threshold (AT. In lieu of human bone, slides (at 20× magnification from bovid cortical bone are used in this study as proxy of human bone. Having been characterized, features with same orientation are used to detect the cement line viewed as the next coaxial layer adjacent to the outermost lamella of the osteon. Employed for this purpose are three attributes for each and every micro-sized feature identified in the osteon lamellar system: (1 orientation, (2 size (ellipse perimeter and (3 Euler number (a topological measure. From a training image, automated parameters for the PCNN network are obtained by forming fitness functions extracted from these attributes. It is found that a 3-way combination of these features attributes yields good representations of the overall osteon boundary (cement line. Near-unity values of classical metrics of quality (precision, sensitivity, specificity, accuracy, and dice suggest that the segments obtained automatically by the optimized artificial intelligent methodology are of high fidelity as compared with manual tracing. For bench marking, cement lines segmented by k-means did not fare as well. An analysis based on the modified Hausdorff distance (MHD of the segmented cement lines also testified to the quality of the detected cement lines vis-a-vis the k-means method.

  8. Repair of microdamage in osteonal cortical bone adjacent to bone screw.

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    Lei Wang

    Full Text Available Up to date, little is known about the repair mode of microdamage in osteonal cortical bone resulting from bone screw implantation. In this study, self-tapping titanium cortical bone screws were inserted into the tibial diaphyses of 24 adult male rabbits. The animals were sacrificed at 1 day, 2 weeks, 1 month and 2 months after surgery. Histomorphometric measurement and confocal microscopy were performed on basic fuchsin stained bone sections to examine the morphological characteristics of microdamage, bone resorption activity and spatial relationship between microdamage and bone resorption. Diffuse and linear cracks were coexisted in peri-screw bone. Intracortical bone resorption was significantly increased 2 weeks after screw installation and reach to the maximum at 1 month. There was no significant difference in bone resorption between 1-month and 2-months groups. Microdamage was significantly decreased within 1 month after surgery. Bone resorption was predisposed to occur in the region of <100 µm from the bone-screw interface, where had extensive diffuse damage mixed with linear cracks. Different patterns of resorption cavities appeared in peri-screw bone. These data suggest that 1 the complex microdamage composed of diffuse damage and linear cracks is a strong stimulator for initiating targeted bone remodeling; 2 bone resorption activities taking place on the surfaces of differently oriented Haversian and Volkmann canals work in a team for the repair of extensive microdamage; 3 targeted bone remodeling is a short-term reaction to microdamage and thereby it may not be able to remove all microdamage resulting from bone screw insertion.

  9. [ANATOMICAL PLATE COMBINED WITH CORTICAL BONE PLATE ALLOGRAFTS FOR TREATMENT OF COMMINUTED FRACTURES OF FEMORAL CONDYLES].

    Science.gov (United States)

    Guo, Zhimin; Gong, Xingxing; Li, Yanwei; Qiu, Xiaochun; Zhang, Meng; Shangguan, Tiancheng; Ao, Qingfang; Liu, Qiang

    2015-01-01

    To summarize the effectiveness of anatomical plate combined with cortical bone plate allografts in the treatment of comminuted fractures of the femoral condyles. Between January 2008 and December 2012, 18 patients with comminuted fractures of the femoral condyles were treated, including 13 males and 5 females with an average age of 45 years (range, 23-65 years). Fractures were caused by traffic accident in 11 cases, by falling from height in 4 cases, and by the other in 3 cases. The locations were the left side in 7 cases and the right side in 11 cases. Of 18 fractures, 12 were open fractures and 6 were closed fractures. The mean time from injury to operation was 6 days (range, 4-15 days). The fixation was performed by anatomical plate combined with cortical bone plate allografts, and autograft bone or allogeneic bone grafting were used. Superficial local skin necrosis occurred in 1 case, and was cured after skin graft, and other incisions achieved primary healing. All patients were followed up 12-36 months (mean, 23 months). X-ray films showed that bone union was achieved within 3-12 months (5.6 months on average). No related complication occurred, such as fixation loosening, refracture, infection, or immunological rejection. According to Merchan et al. criteria for knee joint function evaluation, the results were excellent in 7 cases, good in 9 cases, fair in 1 case, and poor in 1 case at last follow-up; the excellent and good rate was 88.9%. Anatomical plate combined with cortical bone plate allograft fixation is a good method to treat comminuted fractures of the femoral condyles. This method can effectively achieve complete cortical bone on the inside of the femur as well as provide rigid fixation.

  10. Genetic determinants of trabecular and cortical volumetric bone mineral densities and bone microstructure.

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    Lavinia Paternoster

    Full Text Available Most previous genetic epidemiology studies within the field of osteoporosis have focused on the genetics of the complex trait areal bone mineral density (aBMD, not being able to differentiate genetic determinants of cortical volumetric BMD (vBMD, trabecular vBMD, and bone microstructural traits. The objective of this study was to separately identify genetic determinants of these bone traits as analysed by peripheral quantitative computed tomography (pQCT. Separate GWA meta-analyses for cortical and trabecular vBMDs were performed. The cortical vBMD GWA meta-analysis (n = 5,878 followed by replication (n = 1,052 identified genetic variants in four separate loci reaching genome-wide significance (RANKL, rs1021188, p = 3.6×10⁻¹⁴; LOC285735, rs271170, p = 2.7×10⁻¹²; OPG, rs7839059, p = 1.2×10⁻¹⁰; and ESR1/C6orf97, rs6909279, p = 1.1×10⁻⁹. The trabecular vBMD GWA meta-analysis (n = 2,500 followed by replication (n = 1,022 identified one locus reaching genome-wide significance (FMN2/GREM2, rs9287237, p = 1.9×10⁻⁹. High-resolution pQCT analyses, giving information about bone microstructure, were available in a subset of the GOOD cohort (n = 729. rs1021188 was significantly associated with cortical porosity while rs9287237 was significantly associated with trabecular bone fraction. The genetic variant in the FMN2/GREM2 locus was associated with fracture risk in the MrOS Sweden cohort (HR per extra T allele 0.75, 95% confidence interval 0.60-0.93 and GREM2 expression in human osteoblasts. In conclusion, five genetic loci associated with trabecular or cortical vBMD were identified. Two of these (FMN2/GREM2 and LOC285735 are novel bone-related loci, while the other three have previously been reported to be associated with aBMD. The genetic variants associated with cortical and trabecular bone parameters differed, underscoring the complexity of the genetics of bone parameters. We propose

  11. WNT16 influences bone mineral density, cortical bone thickness, bone strength, and osteoporotic fracture risk.

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    Hou-Feng Zheng

    2012-07-01

    Full Text Available We aimed to identify genetic variants associated with cortical bone thickness (CBT and bone mineral density (BMD by performing two separate genome-wide association study (GWAS meta-analyses for CBT in 3 cohorts comprising 5,878 European subjects and for BMD in 5 cohorts comprising 5,672 individuals. We then assessed selected single-nucleotide polymorphisms (SNPs for osteoporotic fracture in 2,023 cases and 3,740 controls. Association with CBT and forearm BMD was tested for ∼2.5 million SNPs in each cohort separately, and results were meta-analyzed using fixed effect meta-analysis. We identified a missense SNP (Thr>Ile; rs2707466 located in the WNT16 gene (7q31, associated with CBT (effect size of -0.11 standard deviations [SD] per C allele, P = 6.2 × 10(-9. This SNP, as well as another nonsynonymous SNP rs2908004 (Gly>Arg, also had genome-wide significant association with forearm BMD (-0.14 SD per C allele, P = 2.3 × 10(-12, and -0.16 SD per G allele, P = 1.2 × 10(-15, respectively. Four genome-wide significant SNPs arising from BMD meta-analysis were tested for association with forearm fracture. SNP rs7776725 in FAM3C, a gene adjacent to WNT16, was associated with a genome-wide significant increased risk of forearm fracture (OR = 1.33, P = 7.3 × 10(-9, with genome-wide suggestive signals from the two missense variants in WNT16 (rs2908004: OR = 1.22, P = 4.9 × 10(-6 and rs2707466: OR = 1.22, P = 7.2 × 10(-6. We next generated a homozygous mouse with targeted disruption of Wnt16. Female Wnt16(-/- mice had 27% (P<0.001 thinner cortical bones at the femur midshaft, and bone strength measures were reduced between 43%-61% (6.5 × 10(-13bone strength, and risk of fracture.

  12. Tensile mechanical properties of swine cortical mandibular bone.

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    Tamar Brosh

    Full Text Available Temporary orthodontic mini implants serve as anchorage devices in orthodontic treatments. Often, they are inserted in the jaw bones, between the roots of the teeth. The stability of the mini implants within the bone is one of the major factors affecting their success and, consequently, that of the orthodontic treatment. Bone mechanical properties are important for implant stability. The aim of this study was to determine the tensile properties of the alveolar and basal mandible bones in a swine model. The diametral compression test was employed to study the properties in two orthogonal directions: mesio-distal and occluso-gingival. Small cylindrical cortical bone specimens (2.6 mm diameter, 1.5 mm thickness were obtained from 7 mandibles using a trephine drill. The sites included different locations (anterior and posterior and aspects (buccal and lingual for a total of 16 specimens from each mandible. The load-displacement curves were continuously monitored while loading half of the specimens in the oclluso-gingival direction and half in the mesio-distal direction. The stiffness was calculated from the linear portion of the curve. The mesio-distal direction was 31% stiffer than the occluso-gingival direction. The basal bone was 40% stiffer than the alveolar bone. The posterior zone was 46% stiffer than the anterior zone. The lingual aspect was stiffer than the buccal aspect. Although bone specimens do not behave as brittle materials, the diametral compression test can be adequately used for determining tensile behavior when only small bone specimens can be obtained. In conclusion, to obtain maximal orthodontic mini implant stability, the force components on the implants should be oriented mostly in the mesio-distal direction.

  13. Chronic Hyperglycemia Modulates Rat Osteoporotic Cortical Bone Microarchitecture into Less Fragile Structures

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    Cristina de Mello-Sampayo

    2017-01-01

    Full Text Available There is controversy concerning the diabetes impact on bone quality, notorious in type 2 diabetic postmenopausal women. One pointed cause might be uncontrolled glycemia. In this study, the effect of chronic hyperglycemia in bone turnover, morphology, and biomechanics was evaluated in female Wistar rats in the presence/absence of estrogens (ovariectomy. Animals (n=28 were divided into sham, ovariectomized (OVX, hyperglycemic (streptozotocin 40 mg/kg, single-dose i.p.-STZ, and hyperglycemic-ovariectomized (STZ + OVX animals. Blood biomarkers were estimated 60 days postovariectomy. Body weight, vertebral microarchitecture (L4-histomorphometry, femur biomechanical properties (bending tests, tibia ultrastructure (scanning electron microscopy, and femur and urinary calcium (atomic absorption were also evaluated. The increased PINP/CTX ratio of hyperglycemic animals and the similar ratio between STZ + OVX and healthy animals contrasting with the lower ratio of OVX (in line with its histomorphometric data suggest a tendency for improved bone formation in hyperglycemic-ovariectomized animals. The increased tibia medullar canal, which contrasts with the unaffected cortical thickness of both hyperglycemic groups while that of OVX decreased, was associated to the increased stiffness and strength of STZ + OVX bones compared to those of OVX, in line with the observed ultrastructure. Concluding, chronic hyperglycemia in ovariectomized female rats causes bone morphological changes that translate positively in the ultrastructure and mechanical properties of cortical bones.

  14. Comparative study between cortical bone graft versus bone dust for reconstruction of cranial burr holes

    OpenAIRE

    Worm, Paulo Valdeci; Ferreira,Nelson Pires; Faria, Mário de Barros; Ferreira, Marcelo Paglioli; Kraemer,Jorge Luiz; Collares, Marcus Vinicius Martins

    2010-01-01

    Background: As a consequence of the progressive evolution of neurosurgical techniques, there has been increasing concern with the esthetic aspects of burr holes. Therefore, the objective of this study was to compare the use of cortical bone graft and bone dust for correcting cranial deformities caused by neurosurgical trephines. Methods: Twenty-three patients were enrolled for cranial burr hole reconstruction with a 1-year follow-up. A total of 108 burr holes were treated; 36 burr holes were ...

  15. Midline lumbar fusion using cortical bone trajectory screws. Preliminary report

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    Mateusz Bielecki

    2016-09-01

    Full Text Available Introduction : Midline lumbar fusion (MIDLF using cortical bone trajectory is an alternative method of transpedicular spinal fusion for degenerative disease. The new entry points’ location and screwdriving direction allow the approach-related morbidity to be reduced. Aim: To present our preliminary experience with the MIDLF technique on the first 5 patients with lumbar degenerative disease and with follow-up of at least 6 months. Material and methods: Retrospective analysis was performed on the first 5 patients with foraminal (4 or central (1 stenosis operated on between December 2014 and February 2015. Three patients were fused at L4–L5 and two at the L5–S1 level. Results: No intra- or post-operative complications occurred with this approach. An improvement regarding the leading symptom in the early postoperative period (sciatica 4/4, claudication 1/1 was achieved in all patients. The mean improvements in the visual analogue scale for low back and leg pain were 2.2 and 4.8 respectively. The mean Oswestry Disability Index scores were 52% (range: 16–82% before surgery and 33% (range: 12–56% at 3-month follow-up (mean improvement 19%. At the most recent follow-up, 4 patients reported the maintenance of the satisfactory result. The early standing and follow-up X-rays showed satisfactory screw placement in all patients. Conclusions : In our initial experience, the MIDLF technique seems to be an encouraging alternative to traditional transpedicular trajectory screws when short level lumbar fusion is needed. Nevertheless, longer observations on larger groups of patients are needed to reliably evaluate the safety of the method and the sustainability of the results.

  16. Bone balance within a cortical BMU: local controls of bone resorption and formation.

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    David W Smith

    Full Text Available Maintaining bone volume during bone turnover by a BMU is known as bone balance. Balance is required to maintain structural integrity of the bone and is often dysregulated in disease. Consequently, understanding how a BMU controls bone balance is of considerable interest. This paper develops a methodology for identifying potential balance controls within a single cortical BMU. The theoretical framework developed offers the possibility of a directed search for biological processes compatible with the constraints of balance control. We first derive general control constraint equations and then introduce constitutive equations to identify potential control processes that link key variables that describe the state of the BMU. The paper describes specific local bone volume balance controls that may be associated with bone resorption and bone formation. Because bone resorption and formation both involve averaging over time, short-term fluctuations in the environment are removed, leaving the control systems to manage deviations in longer-term trends back towards their desired values. The length of time for averaging is much greater for bone formation than for bone resorption, which enables more filtering of variability in the bone formation environment. Remarkably, the duration for averaging of bone formation may also grow to control deviations in long-term trends of bone formation. Providing there is sufficient bone formation capacity by osteoblasts, this leads to an extraordinarily robust control mechanism that is independent of either osteoblast number or the cellular osteoid formation rate. A complex picture begins to emerge for the control of bone volume. Different control relationships may achieve the same objective, and the 'integration of information' occurring within a BMU may be interpreted as different sets of BMU control systems coming to the fore as different information is supplied to the BMU, which in turn leads to different observable

  17. Bone balance within a cortical BMU: local controls of bone resorption and formation.

    Science.gov (United States)

    Smith, David W; Gardiner, Bruce S; Dunstan, Colin

    2012-01-01

    Maintaining bone volume during bone turnover by a BMU is known as bone balance. Balance is required to maintain structural integrity of the bone and is often dysregulated in disease. Consequently, understanding how a BMU controls bone balance is of considerable interest. This paper develops a methodology for identifying potential balance controls within a single cortical BMU. The theoretical framework developed offers the possibility of a directed search for biological processes compatible with the constraints of balance control. We first derive general control constraint equations and then introduce constitutive equations to identify potential control processes that link key variables that describe the state of the BMU. The paper describes specific local bone volume balance controls that may be associated with bone resorption and bone formation. Because bone resorption and formation both involve averaging over time, short-term fluctuations in the environment are removed, leaving the control systems to manage deviations in longer-term trends back towards their desired values. The length of time for averaging is much greater for bone formation than for bone resorption, which enables more filtering of variability in the bone formation environment. Remarkably, the duration for averaging of bone formation may also grow to control deviations in long-term trends of bone formation. Providing there is sufficient bone formation capacity by osteoblasts, this leads to an extraordinarily robust control mechanism that is independent of either osteoblast number or the cellular osteoid formation rate. A complex picture begins to emerge for the control of bone volume. Different control relationships may achieve the same objective, and the 'integration of information' occurring within a BMU may be interpreted as different sets of BMU control systems coming to the fore as different information is supplied to the BMU, which in turn leads to different observable BMU behaviors.

  18. Use of Cortical Bone Screws in Maxillofacial Surgery - A Prospective Study

    Science.gov (United States)

    Satish, Madatanapalli; Rahman, NM Mujeeb; Reddy, V Sridhar; Yuvaraj, A; Muliyar, Sabir; Razak, P Abdul

    2014-01-01

    Background: The aim of this study is to evaluate the various applications of cortical bone screws in oral and maxillofacial surgery. Materials & Methods: The study was conducted in a teaching hospital located in, Bangalore, India, on 20 patients. These patients were categorized into three groups depending on the applications of these screws like, for achieving intermaxillary fixation in Group-1, for treatment of simple, undisplaced fractures by “Tension wire” method in Group-2, and further application of these screws were evaluated in Group-3. Different parameters were used to evaluate the efficacy of these screws. Results: In Group-1(n=12) there was satisfactory occlusion in all the patients with minimal incidence of complications. In Group-2 (n=4) post-operative reduction and fixation was satisfactory and in Group-3 (n=4) the function of these screws was satisfactory when it was used for vestibuloplasty and also as a suspension wiring in treatment of comminuted fracture of zygoma with minimal incidence of complications. Conclusion: Use of cortical bone screws is a valid alternative for achieving intermaxillary fixation, reduction and fixation of simple, undisplaced or minimally displaced fractures through Tension wire method owing to its simplicity, economy and ease of use, and as a fixation method for apically positioned flap in vestibuloplasty procedure. How to cite the article: Satish M, Rahman NM, Reddy VS, Yuvaraj A, Muliyar S, Razak PA. Use of Cortical Bone Screws in Maxillofacial Surgery - A Prospective Study. J Int Oral Health 2014;6(2):62-7. PMID:24876704

  19. Spaceflight-relevant types of ionizing radiation and cortical bone: Potential LET effect?

    Science.gov (United States)

    Lloyd, Shane A.J.; Bandstra, Eric R.; Travis, Neil D.; Nelson, Gregory A.; Bourland, J. Daniel; Pecaut, Michael J.; Gridley, Daila S.; Willey, Jeffrey S.; Bateman, Ted A.

    2008-01-01

    Extended exposure to microgravity conditions results in significant bone loss. Coupled with radiation exposure, this phenomenon may place astronauts at a greater risk for mission-critical fractures. In a previous study, we identified a profound and prolonged loss of trabecular bone (29−39%) in mice following exposure to an acute, 2 Gy dose of radiation simulating both solar and cosmic sources. However, because skeletal strength depends on trabecular and cortical bone, accurate assessment of strength requires analysis of both bone compartments. The objective of the present study was to examine various properties of cortical bone in mice following exposure to multiple types of spaceflight-relevant radiation. Nine-week old, female C57BL/6 mice were sacrificed 110 days after exposure to a single, whole body, 2 Gy dose of gamma, proton, carbon, or iron radiation. Femora were evaluated with biomechanical testing, microcomputed tomography, quantitative histomorphometry, percent mineral content, and micro-hardness analysis. Compared to non-irradiated controls, there were significant differences compared to carbon or iron radiation for only fracture force, medullary area and mineral content. A greater differential effect based on linear energy transfer (LET) level may be present: high-LET (carbon or iron) particle irradiation was associated with a decline in structural properties (maximum force, fracture force, medullary area, and cortical porosity) and mineral composition compared to low-LET radiation (gamma and proton). Bone loss following irradiation appears to be largely specific to trabecular bone and may indicate unique biological microenvironments and microdosimetry conditions. However, the limited time points examined and non-haversian skeletal structure of the mice employed highlight the need for further investigation. PMID:19122806

  20. Two-wave behavior under various conditions of transition area from cancellous bone to cortical bone.

    Science.gov (United States)

    Nagatani, Yoshiki; Mizuno, Katsunori; Matsukawa, Mami

    2014-07-01

    The two-wave phenomenon, the wave separation of a single ultrasonic pulse in cancellous bone, is expected to be a useful tool for the diagnosis of osteoporosis. However, because actual bone has a complicated structure, precise studies on the effect of transition conditions between cortical and cancellous parts are required. This study investigated how the transition condition influenced the two-wave generation using three-dimensional X-ray CT images of an equine radius and a three-dimensional simulation technique. As a result, any changes in the boundary between cortical part and trabecular part, which gives the actual complex structure of bone, did not eliminate the generation of either the primary wave or the secondary wave at least in the condition of clear trabecular alignment. The results led us to the possibility of using the two-wave phenomenon in a diagnostic system for osteoporosis in cases of a complex boundary.

  1. Effect of specimen geometry on tensile strength of cortical bone.

    Science.gov (United States)

    Feng, Liang; Jasiuk, Iwona

    2010-11-01

    We investigate the effect of specimen geometry on the ultimate tensile strength of cortical bone measured by a tensile test. This article is motivated by the fact that there is no clear consensus in the literature on a suitable specimen shape for cortical bone testing. We consider three commonly used tensile test specimen shapes: strip, dumbbell with sharp junctions, and dumbbell with rounded junctions. We conduct this study computationally, using a finite element method, and experimentally by testing porcine femurs. Our results show that local stress concentration factors in the specimen lead to reduced values in the measured tensile strength. The higher the stress concentrations are, the lower is the measured strength. We find that the strip specimens are not a good choice due to high stress concentrations. For the same reason, dumbbell specimens with sharp junctions between the grip and gage sections should also be avoided. The dumbbell shaped tensile test specimens with an arc transition and a maximized radius of fillet are a better choice because such geometry lowers stress concentrations.

  2. Automated classification of mandibular cortical bone on dental panoramic radiographs for early detection of osteoporosis

    Science.gov (United States)

    Horiba, Kazuki; Muramatsu, Chisako; Hayashi, Tatsuro; Fukui, Tatsumasa; Hara, Takeshi; Katsumata, Akitoshi; Fujita, Hiroshi

    2015-03-01

    Findings on dental panoramic radiographs (DPRs) have shown that mandibular cortical index (MCI) based on the morphology of mandibular inferior cortex was significantly correlated with osteoporosis. MCI on DPRs can be categorized into one of three groups and has the high potential for identifying patients with osteoporosis. However, most DPRs are used only for diagnosing dental conditions by dentists in their routine clinical work. Moreover, MCI is not generally quantified but assessed subjectively. In this study, we investigated a computer-aided diagnosis (CAD) system that automatically classifies mandibular cortical bone for detection of osteoporotic patients at early stage. First, an inferior border of mandibular bone was detected by use of an active contour method. Second, regions of interest including the cortical bone are extracted and analyzed for its thickness and roughness. Finally, support vector machine (SVM) differentiate cases into three MCI categories by features including the thickness and roughness. Ninety eight DPRs were used to evaluate our proposed scheme. The number of cases classified to Class I, II, and III by a dental radiologist are 56, 25 and 17 cases, respectively. Experimental result based on the leave-one-out cross-validation evaluation showed that the sensitivities for the classes I, II, and III were 94.6%, 57.7% and 94.1%, respectively. Distribution of the groups in the feature space indicates a possibility of MCI quantification by the proposed method. Therefore, our scheme has a potential in identifying osteoporotic patients at an early stage.

  3. Aging and Fracture of Human Cortical Bone and Tooth Dentin

    Energy Technology Data Exchange (ETDEWEB)

    Ager, Joel; Koester, Kurt J.; Ager III, Joel W.; Ritchie, Robert O.

    2008-05-07

    Mineralized tissues, such as bone and tooth dentin, serve as structural materials in the human body and, as such, have evolved to resist fracture. In assessing their quantitative fracture resistance or toughness, it is important to distinguish between intrinsic toughening mechanisms which function ahead of the crack tip, such as plasticity in metals, and extrinsic mechanisms which function primarily behind the tip, such as crack bridging in ceramics. Bone and dentin derive their resistance to fracture principally from extrinsic toughening mechanisms which have their origins in the hierarchical microstructure of these mineralized tissues. Experimentally, quantification of these toughening mechanisms requires a crack-growth resistance approach, which can be achieved by measuring the crack-driving force, e.g., the stress intensity, as a function of crack extension ("R-curve approach"). Here this methodology is used to study of the effect of aging on the fracture properties of human cortical bone and human dentin in order to discern the microstructural origins of toughness in these materials.

  4. Long bone histology of the subterranean rodent Bathyergus suillus (Bathyergidae): ontogenetic pattern of cortical bone thickening.

    Science.gov (United States)

    Montoya-Sanhueza, Germán; Chinsamy, Anusuya

    2017-02-01

    Patterns of bone development in mammals are best known from terrestrial and cursorial groups, but there is a considerable gap in our understanding of how specializations for life underground affect bone growth and development. Likewise, studies of bone microstructure in wild populations are still scarce, and they often include few individuals and tend to be focused on adults. For these reasons, the processes generating bone microstructural variation at intra- and interspecific levels are not fully understood. This study comprehensively examines the bone microstructure of an extant population of Cape dune molerats, Bathyergus suillus (Bathyergidae), the largest subterranean mammal endemic to the Western Cape of South Africa. The aim of this study is to investigate the postnatal bone growth of B. suillus using undecalcified histological sections (n = 197) of the femur, humerus, tibia-fibula, ulna and radius, including males and females belonging to different ontogenetic and reproductive stages (n = 42). Qualitative histological features demonstrate a wide histodiversity with thickening of the cortex mainly resulting from endosteal and periosteal bone depositions, whilst there is scarce endosteal resorption and remodeling throughout ontogeny. This imbalanced bone modeling allows the tissues deposited during ontogeny to remain relatively intact, thus preserving an excellent record of growth. The distribution of the different bone tissues observed in the cortex depends on ontogenetic status, anatomical features (e.g. muscle attachment structures) and location on the bone (e.g. anterior or lateral). The type of bone microstructure and modeling is discussed in relation to digging behavior, reproduction and physiology of this species. This study is the first histological assessment describing the process of cortical thickening in long bones of a fossorial mammal.

  5. Vascular calcification is associated with cortical bone loss in chronic renal failure rats with and without ovariectomy: the calcification paradox.

    Science.gov (United States)

    De Schutter, Tineke M; Neven, Ellen; Persy, Veerle P; Behets, Geert J; Postnov, Andrei A; De Clerck, Nora M; D'Haese, Patrick C

    2011-01-01

    Increased bone loss has been associated with the development of vascular calcification in patients with chronic renal failure (CRF). In this study, the effect of impaired bone metabolism on aortic calcifications was investigated in uremic rats with or without ovariectomy. CRF was induced by administration of a 0.75% adenine/2.5% protein diet for 4 weeks. In one group, osteoporosis was induced by ovariectomy (CRF-OVX), while the other group underwent a sham-operation instead (CRF). A third group consisted of ovariectomized rats with normal renal function (OVX). At regular time intervals throughout the study, bone status and aortic calcifications were evaluated by in vivo micro-CT. At sacrifice after 6 weeks of CRF, bone histomorphometry was performed and vascular calcification was assessed by bulk calcium analysis and Von Kossa staining. Renal function was significantly impaired in the CRF-OVX and CRF groups. Trabecular bone loss was seen in all groups. In the CRF-OVX and CRF groups, trabecular bone density was restored after adenine withdrawal, which coincided with cortical bone loss and the development of medial calcifications in the aorta. No significant differences with regard to the degree of aortic calcifications were seen between the two CRF groups. Neither cortical bone loss nor calcifications were seen in the OVX group. Cortical bone loss significantly correlated with the severity of vascular calcification in the CRF-OVX and CRF groups, but no associations with trabecular bone changes were found. Cortical rather than trabecular bone loss is associated with the process of calcification in rats with adenine- induced CRF. Copyright © 2011 S. Karger AG, Basel.

  6. Scanning electron microscopy of human cortical bone failure surfaces.

    Science.gov (United States)

    Braidotti, P; Branca, F P; Stagni, L

    1997-02-01

    Undecalcified samples extracted from human femoral shafts are fractured by bending and the fracture surfaces are examined with a scanning electron microscope (SEM). The investigation is performed on both dry and wet (hydrated with a saline solution) specimens. SEM micrographs show patterns in many respects similar to those observed in fractography studies of laminated fiber-reinforced synthetic composites. In particular, dry and wet samples behave like brittle and ductile matrix laminates, respectively. An analysis carried out on the basis of the mechanisms that dominate the fracture process of laminates shows that a reasonable cortical bone model is that of a laminated composite material whose matrix is composed of extracellular noncollagenous calcified proteins, and the reinforcement is constituted by the calcified collagen fiber system.

  7. Cancellous Screws Are Biomechanically Superior to Cortical Screws in Metaphyseal Bone.

    Science.gov (United States)

    Wang, Tim; Boone, Christopher; Behn, Anthony W; Ledesma, Justin B; Bishop, Julius A

    2016-09-01

    Cancellous screws are designed to optimize fixation in metaphyseal bone environments; however, certain clinical situations may require the substitution of cortical screws for use in cancellous bone, such as anatomic constraints, fragment size, or available instrumentation. This study compares the biomechanical properties of commercially available cortical and cancellous screw designs in a synthetic model representing various bone densities. Commercially available, fully threaded, 4.0-mm outer-diameter cortical and cancellous screws were tested in terms of pullout strength and maximum insertion torque in standard-density and osteoporotic cancellous bone models. Pullout strength and maximum insertion torque were both found to be greater for cancellous screws than cortical screws in all synthetic densities tested. The magnitude of difference in pullout strength between cortical and cancellous screws increased with decreasing synthetic bone density. Screw displacement prior to failure and total energy absorbed during pullout strength testing were also significantly greater for cancellous screws in osteoporotic models. Stiffness was greater for cancellous screws in standard and osteoporotic models. Cancellous screws have biomechanical advantages over cortical screws when used in metaphyseal bone, implying the ability to both achieve greater compression and resist displacement at the screw-plate interface. Surgeons should preferentially use cancellous over cortical screws in metaphyseal environments where cortical bone is insufficient for fixation. [Orthopedics.2016; 39(5):e828-e832.].

  8. In vivo monitoring of bone architecture and remodeling after implant insertion: The different responses of cortical and trabecular bone.

    Science.gov (United States)

    Li, Zihui; Kuhn, Gisela; von Salis-Soglio, Marcella; Cooke, Stephen J; Schirmer, Michael; Müller, Ralph; Ruffoni, Davide

    2015-12-01

    The mechanical integrity of the bone-implant system is maintained by the process of bone remodeling. Specifically, the interplay between bone resorption and bone formation is of paramount importance to fully understand the net changes in bone structure occurring in the peri-implant bone, which are eventually responsible for the mechanical stability of the bone-implant system. Using time-lapsed in vivo micro-computed tomography combined with new composite material implants, we were able to characterize the spatio-temporal changes of bone architecture and bone remodeling following implantation in living mice. After insertion, implant stability was attained by a quick and substantial thickening of the cortical shell which counteracted the observed loss of trabecular bone, probably due to the disruption of the trabecular network. Within the trabecular compartment, the rate of bone formation close to the implant was transiently higher than far from the implant mainly due to an increased mineral apposition rate which indicated a higher osteoblastic activity. Conversely, in cortical bone, the higher rate of bone formation close to the implant compared to far away was mostly related to the recruitment of new osteoblasts as indicated by a prevailing mineralizing surface. The behavior of bone resorption also showed dissimilarities between trabecular and cortical bone. In the former, the rate of bone resorption was higher in the peri-implant region and remained elevated during the entire monitoring period. In the latter, bone resorption rate had a bigger value away from the implant and decreased with time. Our approach may help to tune the development of smart implants that can attain a better long-term stability by a local and targeted manipulation of the remodeling process within the cortical and the trabecular compartments and, particularly, in bone of poor health.

  9. Computational Study of the Effect of Cortical Porosity on Ultrasound Wave Propagation in Healthy and Osteoporotic Long Bones

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    Vassiliki T. Potsika

    2016-03-01

    Full Text Available Computational studies on the evaluation of bone status in cases of pathologies have gained significant interest in recent years. This work presents a parametric and systematic numerical study on ultrasound propagation in cortical bone models to investigate the effect of changes in cortical porosity and the occurrence of large basic multicellular units, simply called non-refilled resorption lacunae (RL, on the velocity of the first arriving signal (FAS. Two-dimensional geometries of cortical bone are established for various microstructural models mimicking normal and pathological tissue states. Emphasis is given on the detection of RL formation which may provoke the thinning of the cortical cortex and the increase of porosity at a later stage of the disease. The central excitation frequencies 0.5 and 1 MHz are examined. The proposed configuration consists of one point source and multiple successive receivers in order to calculate the FAS velocity in small propagation paths (local velocity and derive a variation profile along the cortical surface. It was shown that: (a the local FAS velocity can capture porosity changes including the occurrence of RL with different number, size and depth of formation; and (b the excitation frequency 0.5 MHz is more sensitive for the assessment of cortical microstructure.

  10. Comparative cortical bone thickness between the long bones of humans and five common non-human mammal taxa.

    Science.gov (United States)

    Croker, Sarah L; Reed, Warren; Donlon, Denise

    2016-03-01

    The task of identifying fragments of long bone shafts as human or non-human is difficult but necessary, for both forensic and archaeological cases, and a fast simple method is particularly useful. Previous literature suggests there may be differences in the thickness of the cortical bone between these two groups, but this has not been tested thoroughly. The aim of this study was not only to test this suggestion, but also to provide data that could be of practical assistance for future comparisons. The major limb bones (humerus, radius, femur and tibia) of 50 Caucasoid adult skeletons of known age and sex were radiographed, along with corresponding skeletal elements from sheep, pigs, cattle, large dogs and kangaroos. Measurements were taken from the radiographs at five points along the bone shaft, of shaft diameter, cortical bone thickness, and a cortical thickness index (sum of cortices divided by shaft diameter) in both anteroposterior and mediolateral orientations. Each variable for actual cortical bone thickness as well as cortical thickness indices were compared between the human group (split by sex) and each of the non-human groups in turn, using Student's t-tests. Results showed that while significant differences did exist between the human groups and many of the non-human groups, these were not all in the same direction. That is, some variables in the human groups were significantly greater than, and others were significantly less than, the corresponding variable in the non-human groups, depending on the particular non-human group, sex of the human group, or variable under comparison. This was the case for measurements of both actual cortical bone thickness and cortical thickness index. Therefore, for bone shaft fragments for which the skeletal element is unknown, the overlap in cortical bone thickness between different areas of different bones is too great to allow identification using this method alone. However, by providing extensive cortical bone

  11. Effect of porosity, tissue density, and mechanical properties on radial sound speed in human cortical bone

    Energy Technology Data Exchange (ETDEWEB)

    Eneh, C. T. M., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi; Töyräs, J., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi; Jurvelin, J. S., E-mail: jukka.jurvelin@uef.fi [Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, Kuopio FI-70211, Finland and Diagnostic Imaging Center, Kuopio University Hospital, P.O. Box 100, Kuopio FI-70029 (Finland); Malo, M. K. H., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi; Liukkonen, J., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi [Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, Kuopio FI-70211 (Finland); Karjalainen, J. P., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi [Bone Index Finland Ltd., P.O. Box 1188, Kuopio FI-70211 (Finland)

    2016-05-15

    Purpose: The purpose of this study was to investigate the effect of simultaneous changes in cortical porosity, tissue mineral density, and elastic properties on radial speed of sound (SOS) in cortical bone. The authors applied quantitative pulse-echo (PE) ultrasound techniques that hold much potential especially for screening of osteoporosis at primary healthcare facilities. Currently, most PE measurements of cortical thickness, a well-known indicator of fracture risk, use a predefined estimate for SOS in bone to calculate thickness. Due to variation of cortical bone porosity, the use of a constant SOS value propagates to an unknown error in cortical thickness assessment by PE ultrasound. Methods: The authors conducted 2.25 and 5.00 MHz focused PE ultrasound time of flight measurements on femoral diaphyses of 18 cadavers in vitro. Cortical porosities of the samples were determined using microcomputed tomography and related to SOS in the samples. Additionally, the effect of cortical bone porosity and mechanical properties of the calcified matrix on SOS was investigated using numerical finite difference time domain simulations. Results: Both experimental measurements and simulations demonstrated significant negative correlation between radial SOS and cortical porosity (R{sup 2} ≥ 0.493, p < 0.01 and R{sup 2} ≥ 0.989, p < 0.01, respectively). When a constant SOS was assumed for cortical bone, the error due to variation of cortical bone porosity (4.9%–16.4%) was about 6% in the cortical thickness assessment in vitro. Conclusions: Use of a predefined, constant value for radial SOS in cortical bone, i.e., neglecting the effect of measured variation in cortical porosity, propagated to an error of 6% in cortical thickness. This error can be critical as characteristic cortical thinning of 1.10% ± 1.06% per yr decreases bending strength of the distal radius and results in increased fragility in postmenopausal women. Provided that the cortical porosity can be estimated

  12. Cortical and trabecular bone at the forearm show different adaptation patterns in response to tennis playing.

    Science.gov (United States)

    Ducher, Gaële; Prouteau, Stéphanie; Courteix, Daniel; Benhamou, Claude-Laurent

    2004-01-01

    Bone responds to impact-loading activity by increasing its size and/or density. The aim of this study was to compare the magnitude and modality of the bone response between cortical and trabecular bone in the forearms of tennis players. Bone area, bone mineral content (BMC), and bone mineral density (BMD) of the ulna and radius were measured by dual-energy X-ray absorptiometry (DXA) in 57 players (24.5 +/- 5.7 yr old), at three sites: the ultradistal region (50% trabecular bone), the mid-distal regions, and third-distal (mainly cortical bone). At the ultradistal radius, the side-to-side difference in BMD was larger than in bone area (8.4 +/- 5.2% and 4.9 +/- 4.0%, respectively, p < 0.01). In the cortical sites, the asymmetry was lower (p < 0.01) in BMD than in bone area (mid-distal radius: 4.0 +/- 4.3% vs 11.7 +/- 6.8%; third-distal radius: 5.0 +/- 4.8% vs 8.4 +/- 6.2%). The asymmetry in bone area explained 33% of the variance of the asymmetry in BMC at the ultradistal radius, 66% at the mid-distal radius, and 53% at the third-distal radius. The ulna displayed similar results. Cortical and trabecular bone seem to respond differently to mechanical loading. The first one mainly increases its size, whereas the second one preferentially increases its density.

  13. Calcium phosphate cement augmentation of cancellous bone screws can compensate for the absence of cortical fixation.

    Science.gov (United States)

    Stadelmann, Vincent A; Bretton, Elise; Terrier, Alexandre; Procter, Philip; Pioletti, Dominique P

    2010-11-16

    An obvious means to improve the fixation of a cancellous bone screw is to augment the surrounding bone with cement. Previous studies have shown that bone augmentation with Calcium Phosphate (CaP) cement significantly improves screw fixation. Nevertheless, quantitative data about the optimal distribution of CaP cement is not available. The present study aims to show the effect of cement distribution on the screw fixation strength for various cortical thicknesses and to determine the conditions at which cement augmentation can compensate for the absence of cortical fixation in osteoporotic bone. In this study, artificial bone materials were used to mimic osteoporotic cancellous bone and cortical bone of varying thickness. These bone constructs were used to test the fixation strength of cancellous bone screws in different cortical thicknesses and different cement augmentation depths. The cement distribution was measured with microCT. The maximum pullout force was measured experimentally. The microCT analysis revealed a pseudo-conic shape distribution of the cement around the screws. While the maximum pullout strength of the screws in the artificial bone only was 30±7N, it could increase up to approximately 1000N under optimal conditions. Cement augmentation significantly increased pullout force in all cases. The effect of cortical thickness on pullout force was reduced with increased cement augmentation depth. Indeed, cement augmentation without cortical fixation increased pullout forces over that of screws without cement augmentation but with cortical fixation. Since cement augmentation significantly increased pullout force in all cases, we conclude that the loss of cortical fixation can be compensated by cement augmentation.

  14. Comparison of lyophilization, and freezing in honey as techniques to preserve cortical bone allografts used to repair experimental femoral defects in domestic adult cats

    Directory of Open Access Journals (Sweden)

    M.P. Ferreira

    2012-04-01

    Full Text Available Cats with orthopedic conditions are a prominent part of the clinical work of veterinary. Conditions such as comminuted fractures, bone tumors and non-unions are often difficult to repair and may require the use of bone grafts for treatment. This study evaluated cortical bone allografts preserved in honey, frozen or lyophilized for correcting long bone defects created in the diaphysis of the right femur of domestic cats (n=24. In the control group (n=6, the defect was repaired using autogenous cortical bone graft. In the remaining animals (n=6/group, the defect was repaired with cortical bone allografts preserved in honey, frozen or lyophilized. Success of graft incorporation and length of time for consolidation were assessed through clinical, radiographic and histological evaluations performed up to 180 days. In the control, frozen, honey and lyophylized groups, respectively, success of graft incorporation was 91.6%, 83.3%, 75%, and 25%, with corresponding mean length of time for consolidation of 83.1, 78, 105 and 120 days. Incorporation percentage in the lyophilized group was significantly lower than in the frozen and control groups. In conclusion, bone grafts preserved in honey or frozen were effective for repairing cortical defects in the femurs of cats as compared to autogenous cortical bone grafts.

  15. In Vivo Assessment of Elasticity of Child Rib Cortical Bone Using Quantitative Computed Tomography

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    Y. Zhu

    2017-01-01

    Full Text Available Elasticity of the child rib cortical bone is poorly known due to the difficulties in obtaining specimens to perform conventional tests. It was shown on the femoral cortical bone that elasticity is strongly correlated with density for both children and adults through a unique relationship. Thus, it is assumed that the relationships between the elasticity and density of adult rib cortical bones could be expanded to include that of children. This study estimated in vivo the elasticity of the child rib cortical bone using quantitative computed tomography (QCT. Twenty-eight children (from 1 to 18 y.o. were considered. Calibrated QCT images were prescribed for various thoracic pathologies. The Hounsfield units were converted to bone mineral density (BMD. A relationship between the BMD and the elasticity of the rib cortical bone was applied to estimate the elasticity of children’s ribs in vivo. The estimated elasticity increases with growth (7.1 ± 2.5 GPa at 1 y.o. up to 11.6 ± 1.9 GPa at 18 y.o.. This data is in agreement with the few previous values obtained using direct measurements. This methodology paves the way for in vivo assessment of the elasticity of the child cortical bone based on calibrated QCT images.

  16. Antiretroviral therapy and pregnancy: effect on cortical bone status of HIV-infected women

    Directory of Open Access Journals (Sweden)

    V Giacomet

    2012-11-01

    Full Text Available Purpose of the study: Vertical transmission of HIV can be almost eliminated by an appropriate combination of preventative measures, which include the use of combination antiretroviral therapy (ARV during pregnancy, elective cesarean delivery, and avoidance of breastfeeding. Although current ARV demonstrated to be very effective to control virus infection, it has numerous side effects, including negative repercussions on bone mass. Currently there are no data regarding the bone status of HIV-infected women who received ARV during pregnancy. The aim of this study was to evaluate cortical bone status at delivery in a group of HIV-infected women who received ARV during pregnancy, to monitor the changes occurring during the first year post-partum and to compare the results with those obtained in healthy mothers. Methods: We studied 17 HIV-infected and 55 HIV-uninfected healthy women within 3 days from delivery, at 4 and 12 months postpartum (median age 36.4 years. The majority (68% of the HIV-infected mothers was on ARV containing two nucleoside reverse transcriptase inhibitors (NRTI and a protease inhibitor (PI, and 16% was on a regimen containing two NRTIs and two PIs. Other ARV regimens included the use of two NRTIs and one non-NRTI (10%, one NRTI plus one PI (3%, or two NRTIs and three PIs (3%. The median (range exposure to ARV during gestation was 14 (5-35 weeks. The great majority (91% of the women showed an undetectable viral load (<50 cp/mL at delivery. Median CD4 number at delivery was 610 (128 to 1415. Cortical bone status was evaluated by quantitative ultrasonography at the mid-tibia, and bone measurements were expressed as the speed-of-sound (SOS. Summary of results: HIV-infected women after delivery had a median SOS of 3985 (3567–4242 m/s, while the median SOS of healthy women was 4025 (3643–4250. The difference was not significant (t=0.39; P=0.69. SOS measurements at baseline, at 4, and at 12 months are shown in Table 1. SOS values

  17. Nano-structural, compositional and micro-architectural signs of cortical bone fragility at the superolateral femoral neck in elderly hip fracture patients vs. healthy aged controls.

    Science.gov (United States)

    Milovanovic, Petar; Rakocevic, Zlatko; Djonic, Danijela; Zivkovic, Vladimir; Hahn, Michael; Nikolic, Slobodan; Amling, Michael; Busse, Bjoern; Djuric, Marija

    2014-07-01

    To unravel the origins of decreased bone strength in the superolateral femoral neck, we assessed bone structural features across multiple length scales at this cortical fracture initiating region in postmenopausal women with hip fracture and in aged-matched controls. Our combined methodological approach encompassed atomic force microscopy (AFM) characterization of cortical bone nano-structure, assessment of mineral content/distribution via quantitative backscattered electron imaging (qBEI), measurement of bone material properties by reference point indentation, as well as evaluation of cortical micro-architecture and osteocyte lacunar density. Our findings revealed a wide range of differences between the fracture group and the controls, suggesting a number of detrimental changes at various levels of cortical bone hierarchical organization that may render bone fragile. Namely, mineral crystals at external cortical bone surfaces of the fracture group were larger (65.22nm±41.21nm vs. 36.75nm±18.49nm, pfracture group. Fracture cases showed nearly 35% higher cortical porosity and showed significantly reduced osteocyte lacunar density compared to controls (226±27 vs. 247±32#/mm(2), p=0.05). Along with increased crystal size, a shift towards higher mineralization and a tendency to increased cortical porosity and reduced osteocyte lacunar number delineate that cortical bone of the superolateral femoral neck bears distinct signs of fragility at various levels of its structural organization. These results contribute to the understanding of hierarchical bone structure changes in age-related fragility. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. The Hounsfield value for cortical bone geometry in the proximal humerus - an in vitro study

    Energy Technology Data Exchange (ETDEWEB)

    Lim Fat, Daren; Kennedy, Jim; Galvin, Rose; O' Brien, Fergal; Mc Grath, Frank; Mullett, Hannan [Royal College of Surgeons in Ireland, Investigations Carried Out at Anatomy Lab, Dublin (Ireland)

    2012-05-15

    Fractures of the proximal humerus represent a major osteoporotic burden. Recent developments in CT imaging have emphasized the importance of cortical bone thickness distribution in the prevention and management of fragility fractures. We aimed to experimentally define the CT density of cortical bone in the proximal humerus for building cortical geometry maps. With ethical approval, we used ten fresh-frozen human proximal humeri. These were stripped of all soft tissue and high-resolution CT images were then taken. The humeral heads were then subsequently resected to allow access to the metaphyseal area. Using curettes, cancellous bone was removed down to hard cortical bone. Another set of CT images of the reamed specimen was then taken. Using CT imaging software and a CAD interface, we then compared cortical contours at different CT density thresholds to the reference inner cortical contour of our reamed specimens. Working with 3D model representations of these cortical maps, we were able to accurately make distance comparison analyses based on different CT thresholds. We could compute a single closest value at 700 HU. No difference was found in the HU-based contours generated along the 500-900 HU pixels (p = 1.000). The contours were significantly different from those generated at 300, 400, 1,000, and 1,100 HU. A Hounsfield range of 500-900 HU can accurately depict cortical bone geometry in the proximal humerus. Thresholding outside this range leads to statistically significant inaccuracies. Our results concur with a similar range reported in the literature for the proximal femur. Knowledge of regional variations in cortical bone thickness has direct implications for basic science studies on osteoporosis and its treatment, but is also important for the orthopedic surgeon since our decision for treatment options is often guided by local bone quality. (orig.)

  19. In vitro study of adhesive polymethylmethacrylate bone cement bonding to cortical bone in maxillofacial surgery.

    Science.gov (United States)

    Smeets, Ralf; Marx, Rudolf; Kolk, Andreas; Said-Yekta, Sareh; Grosjean, Maurice B; Stoll, Christian; Tinschert, Joachim; Wirtz, Dieter C; Riediger, Dieter; Endres, Kira

    2010-12-01

    In the treatment of midface fractures, the fragments are immobilized using screws and plates for osteosynthesis until reunion has occurred. This method involves drilling holes for the insertion of the screws, which can be associated with additional fracturing of the corresponding bone owing to the complex architecture and thin layers of facial bone. To alleviate this problem, new adhesive techniques for fixing the plates for osteosynthesis have been investigated, mitigating the detrimental effects of screw hole drilling. In the present experimental study, the strength of this adhesive bond and its resistance to hydrolysis were investigated. To determine the adhesive bonding strength, a tension test was implemented. Osteosynthesis plates with screw holes 1.3 mm in diameter were fixed to cortical bone samples of bovine femur using ultraviolet (UV) light-curing polymethylmethacrylate bone cement. To facilitate bonding, the surface of the bone was conditioned with an amphiphilic bonding agent before cementing. UV light curing was implemented using either a conventional UV unit, such as is used in dentistry, or with a specialized UV unit with a limited emission spectrum but high luminosity. Reference control samples were prepared without application of the bone bonding agent. After this procedure, the samples were stored for 1 to 7 days at 37°C submerged in 0.9% saline solution before being subjected to the tension test. Without the bone bonding agent, the bonding strength was 0.2 MPa. The primary average bonding strength at day 0 was 8.5 MPa when cured with the conventional UV unit and 14 MPa for the samples cured with the specialized UV unit. An almost constant average bond strength of 8 and 16 MPa was noted for all samples stored up to 7 days after curing with the conventional and specialized UV unit, respectively. With the development of a new bone bonding agent, a method is now available to promote the bonding between the hydrophilic bone surface and the

  20. Post-traumatic transient cortical blindness in a child with occipital bone fracture.

    Science.gov (United States)

    Ng, Rachel H C

    2016-12-01

    Cortical blindness as sequelae of trauma has been reported in literature but mostly in the setting of occipital cortex or visual tract damages. We present a case of transient cortical blindness in a child following a closed head injury with a non-displaced occipital bone fracture and underlying occipital lobe contusion. We discuss the pathophysiology behind Post-traumatic transient cortical blindness, relevant investigations, and current management.

  1. OPTICAL DENSITY OF CORTICAL BONE MATRIX IS DIMINISHED IN EXPERIMENTALLY INDUCED OSTEOPOROSIS

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    Jovan Janić

    2016-06-01

    Full Text Available Osteoporosis is characterized by low bone mineral density (BMD and abnormalities in bone structural and material properties, with unexplained low trauma fractures. The aim of the present study was to quantify the optical density of cortical bone matrix in rats with experimentally induced osteoporosis by ovariectomy. The experimental group was divided in two equal subgroups, the first sacrificed in the third month after ovariectomy and second sacrificed in the fifth month after ovariectomy. After decalcification, on routinely stained histopathologic sections optical density (OD, standard deviation of OD, mode OD, minimal and maximal OD of cortical bone matrix were estimated. Mean optical density and mode optical density of cortical bone were statistically higher in the control than in the experimental group (p<0.05. Maximal optical density of cortical bone was significantly lower in rats three months after ovariectomy than in other groups. Obtained results indicate that in experimentally induced osteoporosis the optical density of cortical bone matrix is diminished, similarly to low bone mineral density.

  2. Assessing temperature changes in cortical bone using variable flip-angle ultrashort echo-time MRI

    Science.gov (United States)

    Han, Misung; Scott, Serena J.; Ozhinsky, Eugene; Salgaonakar, Vasant A.; Jones, Peter D.; Larson, Peder E. Z.; Diederich, Chris J.; Rieke, Viola; Krug, Roland

    2017-03-01

    MR-guided high-intensity focused ultrasound ablation is a promising, noninvasive method for treatment of bone tumors and palliation of pain. During thermal therapy, temperature mapping is necessary to ensure proper heat deposition in targeted tumors as well as to prevent unnecessary heating in surrounding tissues. Conventional MR thermometry exploits the proton resonant frequency shift of water protons, which normally requires a long echo time; therefore, this method is not appropriate for cortical bone due to its short T2* relaxation time. This work demonstrates that ultrashort echo-time MRI can characterize T1 changes in cortical bone caused by temperature changes. Ex vivo experiments were performed to heat diaphysis segments of bovine femurs with an interstitial ultrasound applicator. The T1 increase in the heated parts of cortical bone was observed. The temerature dependence of T1 in cortical born was also assessed by heating bovine bone samples in a temperature-controlled water bath. T1 mapping of cortical bone enabled by ultrashort echo-time MRI might allow for more accurate characterization of thermal dose during treatment of bone tumors.

  3. Ovariectomy-induced changes in aged beagles : histomorphometry of rib cortical bone.

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, A. K.; Bhattacharyya, M. H.; Miller, S.; Sacco-Gibson, N.; Center for Mechanistic Biology and Biotechnology; Univ. of Utah; Procter & Gamble Pharmaceuticals

    1998-03-01

    Bone loss associated with estrogen depletion is well documented in cancellous bone but less well characterized in cortical bone. The effects of ovariectomy on the aged beagle skeleton were studied by histomorphometric analysis of the cortical bone in sequential rib biopsies. Biopsies were taken from each ovariectomized or sham-operated dog at the time of surgery and at 1, 4, and 8.5 months after surgery. Just prior to each postoperative biopsy, tetracycline, calcein, and xylenol orange, respectively, were administered by a fluorochrome labeling procedure (2d-10d-2d) to provide markers of bone formation. Analysis of sequential rib biopsies provided a means to follow the ovariectomy response over time and to compare each animal against its own baseline. Though ovariectomy did not influence histomorphometric indices at 1 month after surgery, a transient increase in cortical bone formation occurred thereafter, with a sixfold increase over that of sham-operated dogs at 4 months (P < 0.001) and a return to near control levels at 8.5 months. Cortical porosity increased by the fourth month after ovariectomy and remained high at 8.5 months. These data demonstrate for the first time that rib cortical bone is a responsive site for the effects of ovariectomy in aged female dogs.

  4. Increased intra-cortical porosity reduces bone stiffness and strength in pediatric patients with osteogenesis imperfecta.

    Science.gov (United States)

    Vardakastani, V; Saletti, D; Skalli, W; Marry, P; Allain, J M; Adam, C

    2014-12-01

    Osteogenesis imperfecta (OI) is a heritable disease occurring in one out of every 20,000 births. Although it is known that Type I collagen mutation in OI leads to increased bone fragility, the mechanism of this increased susceptibility to fracture is not clear. The aim of this study was to assess the microstructure of cortical bone fragments from patients with osteogenesis imperfecta (OI) using polarized light microscopy, and to correlate microstructural observations with the results of previously performed mechanical compression tests on bone from the same source. Specimens of cortical bone were harvested from the lower limbs of three (3) OI patients at the time of surgery, and were divided into two groups. Group 1 had been subjected to previous micro-mechanical compression testing, while Group 2 had not been subjected to any prior testing. Polarized light microscopy revealed disorganized bone collagen architecture as has been previously observed, as well as a large increase in the areal porosity of the bone compared to typical values for healthy cortical bone, with large (several hundred micron sized), asymmetrical pores. Importantly, the areal porosity of the OI bone samples in Group 1 appears to correlate strongly with their previously measured apparent Young's modulus and compressive strength. Taken together with prior nanoindentation studies on OI bone tissue, the results of this study suggest that increased intra-cortical porosity is responsible for the reduction in macroscopic mechanical properties of OI cortical bone, and therefore that in vivo imaging modalities with resolutions of ~100 μm or less could potentially be used to non-invasively assess bone strength in OI patients. Although the number of subjects in this study is small, these results highlight the importance of further studies in OI bone by groups with access to human OI tissue in order to clarify the relationship between increased porosity and reduced macroscopic mechanical integrity.

  5. Propagation of time-reversed Lamb waves in bovine cortical bone in vitro.

    Science.gov (United States)

    Lee, Kang Il; Yoon, Suk Wang

    2015-01-01

    The present study aims to investigate the propagation of time-reversed Lamb waves in bovine cortical bone in vitro. The time-reversed Lamb waves were successfully launched at 200 kHz in 18 bovine tibiae through a time reversal process of Lamb waves. The group velocities of the time-reversed Lamb waves in the bovine tibiae were measured using the axial transmission technique. They showed a significant correlation with the cortical thickness and tended to follow the theoretical group velocity of the lowest order antisymmetrical Lamb wave fairly well, consistent with the behavior of the slow guided wave in long cortical bones.

  6. A grape-enriched diet increases bone calcium retention and cortical bone properties in ovariectomized rats.

    Science.gov (United States)

    Hohman, Emily E; Weaver, Connie M

    2015-02-01

    Grapes and their associated phytochemicals have been investigated for beneficial effects on cardiovascular health, cancer prevention, and other chronic diseases, but the effect of grape consumption on bone health has not been fully determined. We previously found short-term benefits of grape products on reducing bone turnover in ovariectomized rats. The objective of this study was to determine the long-term benefits of a grape-enriched diet on bone in ovariectomized rats. Rats were ovariectomized at 3 mo of age and were administered a single dose of (45)Ca to prelabel bones at 4 mo of age. After a 1-mo equilibration period, baseline urinary (45)Ca excretion was determined. Rats (n = 22/group) were then randomly assigned to a modified AIN93M diet containing 25% freeze-dried grape powder or to a control diet for 8 wk. Urinary (45)Ca excretion was monitored throughout the study to determine changes in bone (45)Ca retention. Calcium balance was assessed after 1 and 8 wk of consuming the experimental diets, and a calcium kinetic study was performed at 8 wk. After 8 wk, femurs were collected for micro-computed tomographic imaging, 3-point bending, and reference point indentation. Rats fed the grape-enriched diet had 44% greater net bone calcium retention than did rats fed the control diet. There were no differences in calcium balance due to diet at either week 1 or week 8, but there was a significant increase in net calcium absorption (10.6%) and retention (5.7%) from week 1 to week 8 in the grape-enriched diet group only. Grape-enriched diet-fed rats had 3% greater cortical thickness and 11% greater breaking strength. There were no differences in femur bone mineral density, trabecular microarchitecture, or reference point indentation variables due to diet. This study of ovariectomized rats indicates that the consumption of grape products may improve calcium utilization and suppress bone turnover, resulting in improvements in bone quality. © 2015 American Society for

  7. In vitro ultrasonic and mechanic characterization of the modulus of elasticity of children cortical bone.

    Science.gov (United States)

    Berteau, Jean-Philippe; Baron, Cécile; Pithioux, Martine; Launay, Franck; Chabrand, Patrick; Lasaygues, Philippe

    2014-07-01

    The assessment of elastic properties in children's cortical bone is a major challenge for biomechanical engineering community, more widely for health care professionals. Even with classical clinical modalities such as X-ray tomography, MRI, and/or echography, inappropriate diagnosis can result from the lack of reference values for children bone. This study provides values for elastic properties of cortical bone in children using ultrasonic and mechanical measurements, and compares them with adult values. 18 fibula samples from 8 children (5-16 years old, mean age 10.6 years old ±4.4) were compared to 16 fibula samples from 3 elderly adults (more than 65 years old). First, the dynamic modulus of elasticity (Edyn) and Poisson's ratio (ν) are evaluated via an ultrasonic method. Second, the static modulus of elasticity (Esta) is estimated from a 3-point microbending test. The mean values of longitudinal and transverse wave velocities measured at 10 MHz for the children's samples are respectively 3.2mm/μs (±0.5) and 1.8mm/μs (±0.1); for the elderly adults' samples, velocities are respectively 3.5mm/μs (±0.2) and 1.9 mm/μs (±0.09). The mean Edyn and the mean Esta for the children's samples are respectively 15.5 GPa (±3.4) and 9.1 GPa (±3.5); for the elderly adults' samples, they are respectively 16.7 GPa (±1.9) and 5.8 GPa (±2.1). Edyn, ν and Esta are in the same range for children's and elderly adults' bone without any parametric statistical difference; a ranking correlation between Edyn and Esta is shown for the first time.

  8. Trabecular bone of growth plate origin influences both trabecular and cortical morphology in adulthood.

    Science.gov (United States)

    Wang, Qingju; Ghasem-Zadeh, Ali; Wang, Xiao-Fang; Iuliano-Burns, Sandra; Seeman, Ego

    2011-07-01

    Skeletal fragility is common at metaphyseal regions of long bones. The cortices of this region are derived by coalescence of trabeculae around the periphery of the growth plate, not by periosteal apposition, as occurs in the diaphyses. We therefore hypothesized that trabecular bone in childhood predicted both cortical and trabecular morphology in adulthood. To test this hypothesis, we measured distal radial and tibial structure using high-resolution peripheral quantitative computed tomography in 61 daughter-mother pairs, mean age 12.5 years (range 7 to 19 years) and 44.1 years (range 32 to 50 years), respectively. The daughters' trabecular bone volume (BV/TV), thickness, number, and separation predicted the corresponding traits in their mothers. Their trabecular BV/TV also predicted their mothers' cortical thickness (r = 0.32, p = .02). By contrast, the daughters' cortical thickness did not predict their mothers' cortical thickness. The daughters had higher trabecular BV/TV than their mothers (mean ± SD, radius 0.134 ± 0.024 versus 0.124 ± 0.033, p = .03; tibia 0.145 ± 0.021 versus 0.135 ± 0.032, p < .01) owing to greater trabecular number, not thickness, and less trabecular separation. Abnormalities in the development of metaphyseal trabecular bone are likely to influence fragility in both trabecular and cortical bone of this region in adulthood.

  9. Cortical bone development under the growth plate is regulated by mechanical load transfer.

    NARCIS (Netherlands)

    Tanck, E.J.M.; Hannink, G.J.; Ruimerman, R.; Buma, P.; Burger, E.H.; Huiskes, R.

    2006-01-01

    Longitudinal growth of long bones takes place at the growth plates. The growth plate produces new bone trabeculae, which are later resorbed or merged into the cortical shell. This process implies transition of trabecular metaphyseal sections into diaphyseal sections. We hypothesize that the developm

  10. Geometric-attributes-based segmentation of cortical bone slides using optimized neural networks.

    Science.gov (United States)

    Hage, Ilige S; Hamade, Ramsey F

    2016-05-01

    In cortical bone, solid (lamellar and interstitial) matrix occupies space left over by porous microfeatures such as Haversian canals, lacunae, and canaliculi-containing clusters. In this work, pulse-coupled neural networks (PCNN) were used to automatically distinguish the microfeatures present in histology slides of cortical bone. The networks' parameters were optimized using particle swarm optimization (PSO). When forming the fitness functions for the PSO, we considered the microfeatures' geometric attributes-namely, their size (based on measures of elliptical perimeter or area), shape (based on measures of compactness or the ratio of minor axis length to major axis length), and a two-way combination of these two geometric attributes. This hybrid PCNN-PSO method was further enhanced for pulse evaluation by combination with yet another method, adaptive threshold (AT), where the PCNN algorithm is repeated until the best threshold is found corresponding to the maximum variance between two segmented regions. Together, this framework of using PCNN-PSO-AT constitutes, we believe, a novel framework in biomedical imaging. Using this framework and extracting microfeatures from only one training image, we successfully extracted microfeatures from other test images. The high fidelity of all resultant segments was established using quantitative metrics such as precision, specificity, and Dice indices.

  11. The importance of murine cortical bone microstructure for microcrack initiation and propagation.

    Science.gov (United States)

    Voide, R; Schneider, P; Stauber, M; van Lenthe, G H; Stampanoni, M; Müller, R

    2011-12-01

    In order to better understand bone postyield behavior and consequently bone failure behavior, this study aimed first to investigate cortical bone microstructure and second, to relate cortical bone microstructure to microdamage initiation and propagation in C57BL/6 (B6) and C3H/He (C3H) mice; two murine inbred strains known for their differences in bone phenotype. Murine femora of B6 and C3H were loaded axially under compression in a stepwise manner. For each loading step, 3D data sets at a nominal resolution of 700 nm were acquired by means of synchrotron radiation-based computed tomography. Cortical bone microstructure was divided into three phases: the canal network, the osteocyte lacunar system, and microdamage. Canal volume density and canal unit volume both correlated highly to crack number density (canal volume density: R(2)=0.64, pcanal unit volume: R(2)=0.75, pcanal units in C3H bone were responsible for more microdamage accumulation compared to B6 bones. This more pronounced microdamage accumulation due to large intracortical bone voids, which eventually leads to a fatal macrocrack (fracture), represents a potential contributing factor to the higher incidence of bone fractures in the elderly. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Temperature Values Variability in Piezoelectric Implant Site Preparation: Differences between Cortical and Corticocancellous Bovine Bone

    Directory of Open Access Journals (Sweden)

    Luca Lamazza

    2016-01-01

    Full Text Available Purpose. Various parameters can influence temperature rise and detection during implant site preparation. The aim of this study is to investigate local temperature values in cortical and corticocancellous bovine bone during early stages of piezoelectric implant site preparation. Materials and Methods. 20 osteotomies were performed using a diamond tip (IM1s, Mectron Medical Technology, Carasco, Italy on two different types of bovine bone samples, cortical and corticocancellous, respectively. A standardized protocol was designed to provide constant working conditions. Temperatures were measured in real time at a fixed position by a fiber optic thermometer. Results. Significantly higher drilling time (154.90 sec versus 99.00 sec; p<0.0001 and temperatures (39.26°C versus 34.73°C; p=0.043 were observed in the cortical group compared to the corticocancellous group. A remarkable variability of results characterized the corticocancellous blocks as compared to the blocks of pure cortical bone. Conclusion. Bone samples can influence heat generation during in vitro implant site preparation. When compared to cortical bone, corticocancellous samples present more variability in temperature values. Even controlling most experimental factors, the impact of bone samples still remains one of the main causes of temperature variability.

  13. Cortical and Trabecular Bone Microstructure Did Not Recover at Weight-Bearing Skeletal Sites and Progressively Deteriorated at Non-Weight-Bearing Sites During the Year Following International Space Station Missions.

    Science.gov (United States)

    Vico, Laurence; van Rietbergen, Bert; Vilayphiou, Nicolas; Linossier, Marie-Thérèse; Locrelle, Hervé; Normand, Myriam; Zouch, Mohamed; Gerbaix, Maude; Bonnet, Nicolas; Novikov, Valery; Thomas, Thierry; Vassilieva, Galina

    2017-06-02

    Risk for premature osteoporosis is a major health concern in astronauts and cosmonauts; the reversibility of the bone lost at the weight-bearing bone sites is not established, although it is suspected to take longer than the mission length. The bone three-dimensional structure and strength that could be uniquely affected by weightlessness is currently unknown. Our objective is to evaluate bone mass, microarchitecture, and strength of weight-bearing and non-weight-bearing bone in 13 cosmonauts before and for 12 months after a 4-month to 6-month sojourn in the International Space Station (ISS). Standard and advanced evaluations of trabecular and cortical parameters were performed using high-resolution peripheral quantitative computed tomography. In particular, cortical analyses involved determination of the largest common volume of each successive individual scan to improve the precision of cortical porosity and density measurements. Bone resorption and formation serum markers, and markers reflecting osteocyte activity or periosteal metabolism (sclerostin, periostin) were evaluated. At the tibia, in addition to decreased bone mineral densities at cortical and trabecular compartments, a 4% decrease in cortical thickness and a 15% increase in cortical porosity were observed at landing. Cortical size and density subsequently recovered and serum periostin changes were associated with cortical recovery during the year after landing. However, tibial cortical porosity or trabecular bone failed to recover, resulting in compromised strength. The radius, preserved at landing, unexpectedly developed postflight fragility, from 3 months post-landing onward, particularly in its cortical structure. Remodeling markers, uncoupled in favor of bone resorption at landing, returned to preflight values within 6 months, then declined farther to lower than preflight values. Our findings highlight the need for specific protective measures not only during, but also after spaceflight, because

  14. Influence of bone microstructure on the mechanical properties of skull cortical bone - A combined experimental and computational approach.

    Science.gov (United States)

    Boruah, Sourabh; Subit, Damien L; Paskoff, Glenn R; Shender, Barry S; Crandall, Jeff R; Salzar, Robert S

    2017-01-01

    The strength and compliance of the dense cortical layers of the human skull have been examined since the beginning of the 20th century with the wide range in the observed mechanical properties attributed to natural biological variance. Since this variance may be explained by the difference in structural arrangement of bone tissue, micro-computed tomography (µCT) was used in conjunction with mechanical testing to study the relationship between the microstructure of human skull cortical coupons and their mechanical response. Ninety-seven bone samples were machined from the cortical tables of the calvaria of ten fresh post mortem human surrogates and tested in dynamic tension until failure. A linear response between stress and strain was observed until close to failure, which occurred at 0.6% strain on average. The effective modulus of elasticity for the coupons was 12.01 ± 3.28GPa. Porosity of the test specimens, determined from µCT, could explain only 51% of the variation of their effective elastic modulus. Finite element (FE) models of the tested specimens built from µCT images indicated that modeling the microstructural arrangement of the bone, in addition to the porosity, led to a marginal improvement of the coefficient of determination to 54%. Modulus for skull cortical bone for an element size of 50µm was estimated to be 19GPa at an average. Unlike the load bearing bones of the body, almost half of the variance in the mechanical properties of cortical bone from the skull may be attributed to differences at the sub-osteon (< 50µm) level. ANOVA tests indicated that effective failure stress and strain varied significantly between the frontal and parietal bones, while the bone phase modulus was different for the superior and inferior aspects of the calvarium. The micro FE models did not indicate any anisotropy attributable to the pores observable under µCT.

  15. Drilling in cortical bone: a finite element model and experimental investigations.

    Science.gov (United States)

    Lughmani, Waqas A; Bouazza-Marouf, Kaddour; Ashcroft, Ian

    2015-02-01

    Bone drilling is an essential part of many orthopaedic surgery procedures, including those for internal fixation and for attaching prosthetics. Estimation and control of bone drilling forces are critical to prevent drill-bit breakthrough, excessive heat generation, and mechanical damage to the bone. An experimental and computational study of drilling in cortical bone has been conducted. A 3D finite element (FE) model for prediction of thrust forces experienced during bone drilling has been developed. The model incorporates the dynamic characteristics involved in the process along with geometrical considerations. An elastic-plastic material model is used to predict the behaviour of cortical bone during drilling. The average critical thrust forces and torques obtained using FE analysis are found to be in good agreement with the experimental results.

  16. Cortical lamina technique: A therapeutic approach for lateral ridge augmentation using guided bone regeneration

    Science.gov (United States)

    Thomas, Raison; Baron, Tarun-Kumar; Shah, Rucha; Mehta, Dhoom-Singh

    2017-01-01

    Background The present study aimed at evaluating the efficacy of a novel technique, the bone lamina technique, in horizontal ridge augmentation clinically & radiographically using a combination of allogenic cortical shell, particulate xenograft and resorbable collagen membrane. Material and Methods Localized horizontal ridge defects, in ten patients (6 male, 4 female), with bucco-palatal ridge width less than 5 mm were included in this study. Localised ridge augmentation was performed using bone lamina technique with mineralised allogenic shell of 1 mm thickness trimmed to the appropriate size using stereo-lithographic models and fixed to the recipient site with stainless steel micro-screws of 1 mm diameter. The space between the shell & host bone was filled with particulate xenograft followed by placement of collagen membrane and primary closure of the site. Clinical parameters including ridge width before & after flap reflection & radiographic (CBCT) ridge width measurements were recorded pre-operatively,and six months after the augmentation procedure. Results obtained were analysed statistically. Results The mean clinical ridge width before flap reflection (BFR), after flap reflection (AFR) & radiographically was 3.7 ± 0.74 mm, 2 ± 0.70 mm & 1.77 ± 0.71 mm respectively at baseline which increased to 6.8 ± 0.95 mm, 5.15 ± 0.98 mm & 4.90 ± 0.90 mm with a mean gain in ridge width of 3.1 ± 0.63 mm (p< 0.005), 3.15 ± 0.63 mm (p<0.005) & 3.13 ± 0.70 mm (p< 0.005) respectively. Conclusions The present study demonstrates that bone lamina technique can be effective means of horizontal ridge augmentation and the use of mineralized allograft in combination with xenograft and collagen membrane leads to good amount of bone regeneration for subsequent implant placement. Key words:Dental implant, guided bone regeneration, horizontal ridge defect, ridge augmentation. PMID:28149458

  17. Specifications for machining the bovine cortical bone in relation to its microstructure.

    Science.gov (United States)

    Sugita, Naohiko; Mitsuishi, Mamoru

    2009-12-11

    Until date, many devices have been developed for cutting human bones during orthopedic surgeries. However, bones are anisotropic material, and their machining characteristics depend on the tool feed direction. In this study, microcutting of the bovine cortical bone is performed and its structure observed under a microscope. Furthermore, the formation of cutting chips and measurement of the cutting force during bone machining are dynamically observed while considering the anisotropy of bone tissue. In particular, the fracture of secondary osteons and crack propagation in bones are observed and analyzed. The results indicate that when the cut depth exceeds 20mum and is greater than the interval of concentric lamellae, cracks are formed together with chips. A new method for bone machining is proposed. This method is based on the characteristics of crack propagation in bones and is expected to produce low mechanical stress and realize highly efficient and precise machining of living tissues such as bones.

  18. Benefits of mineralized bone cortical allograft for immediate implant placement in extraction sites: an in vivo study in dogs

    Science.gov (United States)

    2016-01-01

    Purpose The aim of the present study was to evaluate the effectiveness of using a mineralized bone cortical allograft (MBCA), with or without a resorbable collagenous membrane derived from bovine pericardium, on alveolar bone remodeling after immediate implant placement in a dog model. Methods Six mongrel dogs were included. The test and control sites were randomly selected. Four biradicular premolars were extracted from the mandible. In control sites, implants without an allograft or membrane were placed immediately in the fresh extraction sockets. In the test sites, an MBCA was placed to fill the gap between the bone socket wall and implant, with or without a resorbable collagenous membrane. Specimens were collected after 1 and 3 months. The amount of residual particles and new bone quality were evaluated by histomorphometry. Results Few residual graft particles were observed to be closely embedded in the new bone without any contact with the implant surface. The allograft combined with a resorbable collagen membrane limited the resorption of the buccal wall in height and width. The histological quality of the new bone was equivalent to that of the original bone. The MBCA improved the quality of new bone formation, with few residual particles observed at 3 months. Conclusions The preliminary results of this animal study indicate a real benefit in obtaining new bone as well as in enhancing osseointegration due to the high resorbability of cortical allograft particles, in comparison to the results of xenografts or other biomaterials (mineralized or demineralized cancellous allografts) that have been presented in the literature. Furthermore, the use of an MBCA combined with a collagen membrane in extraction and immediate implant placement limited the extent of post-extraction resorption. PMID:27800212

  19. Mechanistic fracture criteria for the failure of human cortical bone

    Energy Technology Data Exchange (ETDEWEB)

    Nalla, Ravi K.; Kinney, John H.; Ritchie, Robert O.

    2002-12-13

    A mechanistic understanding of fracture in human bone is critical to predicting fracture risk associated with age and disease. Despite extensive work, a mechanistic framework for describing how the underlying microstructure affects the failure mode in bone is lacking.

  20. A histological investigation on tissue responses to titanium implants in cortical bone of the rat femur.

    Science.gov (United States)

    Ohtsu, A; Kusakari, H; Maeda, T; Takano, Y

    1997-03-01

    Implant materials are placed under various sites-including cortical bone, spongy bone, and bone marrow-at the same time according to the depth at implantation. Although cortical bone is an important site for the prognosis of implantation, detailed reports on tissue responses to implantation have been meager. The present study aims to reveal tissue responses to pure titanium implantation in rat femoris cortical bone. The rats received titanium bars surgically in their femurs and were sacrificed 1 day to 40 weeks post-implantation. The prepared tissue specimens were processed for light and transmission electron microscopy (TEM). Further histochemical detections were performed. One day post-implantation, empty osteocytic lacunae indicating degeneration of osteocytes were found in pre-existing cortical bone around the implant. Such pre-existing bone was replaced by new bone, but remained in part even 40 weeks post-implantation. Light microscopy showed that direct contact between the implant and new bone was identified 12 weeks post-implantation. Chronological and ultrastructural observation showed that new bone deposition appeared to proceed toward the implant, and that the intervening layer at the interface was derived from the degenerated debris of multinucleated giant cells and/or osteoblasts. Furthermore, it seemed that the width of intervening layer varied in relation to the distance from the blood vessels. The cells showing tartrate resistant acid phosphatase activity possessed cytological features of osteoclasts under TEM; they were frequently observed in perivascular sites near the implants even after osseointegration, suggesting that bone remodeling took place steadily around the implant.

  1. Repair of sheep long bone cortical defects filled with COLLOSS, COLLOSS E, OSSAPLAST, and fresh iliac crest autograft.

    Science.gov (United States)

    Huffer, William E; Benedict, James J; Turner, A S; Briest, Arne; Rettenmaier, Robert; Springer, Marco; Walboomers, X F

    2007-08-01

    COLLOSS and COLLOSS E are osteoinductive bone void fillers consisting of bone collagen and noncollagenous proteins from bovine and equine bone, respectively. The aim of this study was to compare COLLOSS, COLLOSS E, iliac bone autograft, sintered beta tricalcium phosphate (beta-TCP; OSSAPLAST), and COLLOSS E plus OSSAPLAST. Materials were placed for 4, 8, or 24 weeks in 5-mm cortical bone defects in sheep long bones. Histological sections in a plane perpendicular to the long axis of the bone were used to measure the total repair area (original defect plus callus) and the area of bone within the total repair area. The incidence of defect union was also evaluated. At 4 and 8 weeks, defects treated with COLLOSS and COLLOSS E with or without OSSAPLAST had total repair and bone areas equivalent to autograft, and larger than OSSAPLAST-treated defects. At 8 weeks, the incidence of defect union was higher in defects treated with autograft or COLLOSS E plus OSSAPLAST than in untreated defects. At 24 weeks, the incidence of union was 100% in all treatment groups and 0% in untreated defects. The incidence of union was related to the degree of remodeling between 8 and 24 weeks. This was greater in all treated than nontreated defects. In conclusion, COLLOSS and COLLOSS E were equivalent to each other and to autograft, and superior to beta-TCP, in this study model.

  2. Non destructive characterization of cortical bone micro-damage by nonlinear resonant ultrasound spectroscopy.

    Directory of Open Access Journals (Sweden)

    Sylvain Haupert

    Full Text Available The objective of the study was to evaluate the ability of a nonlinear ultrasound technique, the so-called nonlinear resonant ultrasound spectroscopy (NRUS technique, for detecting early microdamage accumulation in cortical bone induced by four-point bending fatigue. Small parallelepiped beam-shaped human cortical bone specimens were subjected to cyclic four-point bending fatigue in several steps. The specimens were prepared to control damage localization during four-point bending fatigue cycling and to unambiguously identify resonant modes for NRUS measurements. NRUS measurements were achieved to follow the evolution of the nonlinear hysteretic elastic behavior during fatigue-induced damage. After each fatigue step, a small number of specimens was removed from the protocol and set apart to quantitatively assess the microcrack number density and length using synchrotron radiation micro-computed tomography (SR-µCT. The results showed a significant effect of damage steps on the nonlinear hysteretic elastic behavior. No significant change in the overall length of microcracks was observed in damaged regions compared to the load-free control regions. Only an increased number of shortest microcracks, those in the lowest quartile, was noticed. This was suggestive of newly formed microcracks during the early phases of damage accumulation. The variation of nonlinear hysteretic elastic behavior was significantly correlated to the variation of the density of short microcracks. Our results suggest that the nonlinear hysteretic elastic behavior is sensitive to early bone microdamage. Therefore NRUS technique can be used to monitor fatigue microdamage progression in in vitro experiments.

  3. Early cortical bone healing around loaded titanium implants: a histological study in the rabbit.

    Science.gov (United States)

    Slaets, Elke; Naert, Ignace; Carmeliet, Geert; Duyck, Joke

    2009-02-01

    To identify the role of immediate implant loading on the early phases of the bone healing responses. Implants were placed in rabbit tibial diaphyses and left to heal for 3, 7, 14, 28 or 42 days. Half of the animals received an immediate loading protocol of 2.2 N at 3 Hz for 1800 cycles and 5 days/week, whereas the others served as unloaded controls. Histological assessment was combined with histomorphometrical measurements. At early time-points, an endosteal and periosteal new bone formation was found, while the cortex itself contained damaged osteocytes. At later time-points, new bone formation was also found at the cortical level itself. Differences between groups were found mainly in this new bone formation process, with larger reactions for the endosteal and periosteal bone in the loaded group after 28 and 42 days, respectively. At the end-point of the experiment, bone formation at the cortical level was reduced in the loaded group compared with the control group. These results show that the immediate loading protocol caused no differences in the sequential events leading to osseointegration in cortical bone. However, the processes of new bone formation originating from the endosteum and the periosteum lasted longer compared with the unloaded controls.

  4. Variations of mechanical property of out circumferential lamellae in cortical bone along the radial by nanoindentation

    Directory of Open Access Journals (Sweden)

    Xingdong Sun

    2016-11-01

    Full Text Available Because the out circumferential lamellae have a special protective effect on the cortical bone, it is very important to understand the variations of the mechanical property of the out circumferential lamellae in cortical bone. For the purpose, the elasticity modulus and hardness of out circumferential lamellae in cortical bone were investigated in two orthogonal planes by nanoindentation, and the comparisons were made for both elasticity modulus and hardness between the two orthogonal planes. From the experiments, the decreasing trend was discovered for elasticity modulus from inside to outside in the transverse plane and ruleless variations tendency was presented in the longitudinal plane. The hardness presented the same variations in two orthogonal planes with elasticity modulus in respective plane. In the same layer, the elasticity modulus in the transverse plane was higher than that in the longitudinal plane, and the difference values between them turned to be smaller. In contrast, the hardness in the longitudinal plane was higher than that in the transverse plane in all the layers. From the heterogeneity and the microstructure of the material, the influence factors were discussed. A soft to hard structure model was put forward, and the coordinating protection mechanism of buffer and support was described. Investigation of variations of mechanical properties of out circumferential lamellae in cortical bone can provide some new understanding in researches of fracture of bone, interface load effect and design of bone graft.

  5. The effects of glucocorticoid on microarchitecture, collagen, mineral and mechanical properties of sheep femur cortical bone

    DEFF Research Database (Denmark)

    Ding, Ming; Danielsen, Carl C; Overgaard, Søren

    mechanical properties in the glucocorticoid-2. In conclusion, 7 months glucocorticoid treatment with malnutrition had significant impact on cortical microarchitecture of sheep femur midshaft. These changes occurred particularly 3 months after the glucocorticoid cessation suggesting a delayed effect......The effects of glucocorticoid on microarchitecture, collagen, mineral and mechanical properties of sheep femur cortical bone – Validation of large animal model for tissue engineering and biomaterial research Ming Ding,1* Carl Christian Danielsen,2 Søren Overgaard1 1Orthopaedic Research Laboratory...

  6. Acute hypothalamic suppression significantly affects trabecular bone but not cortical bone following recovery and ovariectomy surgery in a rat model

    Directory of Open Access Journals (Sweden)

    Vanessa R. Yingling

    2016-01-01

    Full Text Available Background. Osteoporosis is “a pediatric disease with geriatric consequences.” Bone morphology and tissue quality co-adapt during ontogeny for sufficient bone stiffness. Altered bone morphology from hypothalamic amenorrhea, a risk factor for low bone mass in women, may affect bone strength later in life. Our purpose was to determine if altered morphology following hypothalamic suppression during development affects cortical bone strength and trabecular bone volume (BV/TV at maturity.Methods. Female rats (25 days old were assigned to a control (C group (n = 45 that received saline injections (.2 cc or an experimental group (GnRH-a (n = 45 that received gonadotropin releasing hormone antagonist injections (.24 mg per dose for 25 days. Fifteen animals from each group were sacrificed immediately after the injection protocol at Day 50 (C, GnRH-a. The remaining animals recovered for 135 days and a subset of each group was sacrificed at Day 185 ((C-R (n = 15 and (G-R (n = 15. The remaining animals had an ovariectomy surgery (OVX at 185 days of age and were sacrificed 40 days later (C-OVX (n = 15 and (G-OVX (n = 15. After sacrifice femurs were mechanically tested and scanned using micro CT. Serum C-terminal telopeptides (CTX and insulin-like growth factor 1 (IGF-1 were measured. Two-way ANOVA (2 groups (GnRH-a and Control X 3 time points (Injection Protocol, Recovery, post-OVX was computed.Results. GnRH-a injections suppressed uterine weights (72% and increased CTX levels by 59%. Bone stiffness was greater in the GnRH-a groups compared to C. Ash content and cortical bone area were similar between groups at all time points. Polar moment of inertia, a measure of bone architecture, was 15% larger in the GnRH-a group and remained larger than C (19% following recovery. Both the polar moment of inertia and cortical area increased linearly with the increases in body weight. Following the injection protocol, trabecular BV/TV was 31% lower in the Gn

  7. The effects of glucocorticoid on microarchitecture, collagen, mineral and mechanical properties of sheep femur cortical bone

    DEFF Research Database (Denmark)

    Ding, Ming; Danielsen, Carl C; Overgaard, Søren

    2010-01-01

    The effects of glucocorticoid on microarchitecture, collagen, mineral and mechanical properties of sheep femur cortical bone – Validation of large animal model for tissue engineering and biomaterial research Ming Ding,1* Carl Christian Danielsen,2 Søren Overgaard1 1Orthopaedic Research Laboratory...... treatment. Group 3 was left untreated and served as the controls. All sheep received restricted diet with low calcium and phosphorus. At sacrifice, cortical bone samples from the femur midshaft of sheep were harvested, micro-CT scanned and tested in 3 point bending and in tensile. Bone collagen and mineral...... mechanical properties in the glucocorticoid-2. In conclusion, 7 months glucocorticoid treatment with malnutrition had significant impact on cortical microarchitecture of sheep femur midshaft. These changes occurred particularly 3 months after the glucocorticoid cessation suggesting a delayed effect...

  8. Mandibular Inferior Cortical Bone Thickness on Panoramic Radiographs in Patients using Bisphosphonates

    Science.gov (United States)

    Torres, Sandra R.; Chen, Curtis S. K.; Leroux, Brian G.; Lee, Peggy P.; Hollender, Lars G.; Lloid, Michelle; Drew, Shane Patrick; Schubert, Mark M.

    2015-01-01

    Objective To detect dimensional changes in the mandibular cortical bone associated with bisphosphonate (BP) use and to correlate the measurements of the cortical bone with the cumulative dose of BP therapy. Methods Mandibular inferior cortical bone thickness (MICBT) was measured under the mental foramen from panoramic radiographs of subjects using BP with and without bisphosphonate related osteonecrosis of the jaws (BRONJ) and controls. Results The highest mean MICBT was observed in BRONJ subjects 6.81 (± 1.35 mm), when compared to subjects using BP 5.44 (± 1.09 mm) and controls 4.79 (± 0.85 mm; p<0.01). The mean MICBT of BRONJ subjects was significantly higher than that of subjects using BP without BRONJ. There was a correlation between MICBT and cumulative dose of zolendronate. Conclusion The MICBT on panoramic radiograph is a potentially useful tool for the detection of dimensional changes associated with BP therapy. PMID:25864820

  9. Modalities for Visualization of Cortical Bone Remodeling: The Past, Present, and Future.

    Science.gov (United States)

    Harrison, Kimberly D; Cooper, David M L

    2015-01-01

    Bone's ability to respond to load-related phenomena and repair microdamage is achieved through the remodeling process, which renews bone by activating groups of cells known as basic multicellular units (BMUs). The products of BMUs, secondary osteons, have been extensively studied via classic two-dimensional techniques, which have provided a wealth of information on how histomorphology relates to skeletal structure and function. Remodeling is critical in maintaining healthy bone tissue; however, in osteoporotic bone, imbalanced resorption results in increased bone fragility and fracture. With increasing life expectancy, such degenerative bone diseases are a growing concern. The three-dimensional (3D) morphology of BMUs and their correlation to function, however, are not well-characterized and little is known about the specific mechanisms that initiate and regulate their activity within cortical bone. We believe a key limitation has been the lack of 3D information about BMU morphology and activity. Thus, this paper reviews methodologies for 3D investigation of cortical bone remodeling and, specifically, structures associated with BMU activity (resorption spaces) and the structures they create (secondary osteons), spanning from histology to modern ex vivo imaging modalities, culminating with the growing potential of in vivo imaging. This collection of papers focuses on the theme of "putting the 'why' back into bone architecture." Remodeling is one of two mechanisms "how" bone structure is dynamically modified and thus an improved 3D understanding of this fundamental process is crucial to ultimately understanding the "why."

  10. Calorie restriction aggravated cortical and trabecular bone architecture in ovariectomy-induced estrogen-deficient rats.

    Science.gov (United States)

    Ahn, Hyejin; Seo, Dong-Hyun; Kim, Han Sung; Choue, Ryowon

    2014-08-01

    We hypothesized that calorie restriction (CR) and estrogen deficiency (ovariectomy [OVX]) would aggravate bone biomarkers and structural parameters in rats. Seven-week-old female Sprague-Dawley rats were randomized to sham-operated groups and fed either an ad libitum diet (SHAM-AL) or a CR diet (SHAM-CR); ovariectomy-operated groups were fed an ad libitum diet (OVX-AL) or a CR diet (OVX-CR). For 8 weeks, the OVX-AL and SHAM-AL groups were fed the same diet, whereas CR groups were fed a diet containing 50% fewer calories. Bone-related biomarkers and structural parameters (OC; deoxypyridinoline [DPD]; N-terminal telopeptide, NTx; architecture and mineralization; and microcomputed tomography images) were analyzed at the end of the experiment. The serum OC levels of calorie-restricted groups (SHAM-CR and OVX-CR) were significantly lower than those of the AL groups (SHAM-AL and OVX-AL) (P bone, the calorie-restricted and ovariectomized groups had lower values of bone volume to total volume, trabecular number, and bone mineral density, but higher values of trabecular separation than those of their counterparts (P bone, the calorie-restricted groups had reduced values of bone volume, mean polar moment of inertia, and cortical thickness compared to the AL groups (P bone; CR has detrimental effects on trabecular and cortical bone; and estrogen deficiency only had an effect on trabecular bone. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. A preliminary investigation of the dynamic viscoelastic relaxation of bovine cortical bone

    Directory of Open Access Journals (Sweden)

    Loete T.J.C.

    2015-01-01

    Full Text Available A new experimental approach is proposed to characterize the dynamic viscoelastic relaxation behaviour of cortical bone. Theoretical models are presented to show that a linear viscoelastic material, when allowed to relax between two long elastic bars, will produce stress, strain and strain rate histories that contain characteristic features. Furthermore, typical experimental results are presented to show that these characteristic features are observed during split Hopkinson bar tests on bovine cortical bone using a Cone-in-Tube striker. The interpretation of this behaviour in the context of a standard linear viscoelastic model is discussed.

  12. Nonlinear hierarchical multiscale modeling of cortical bone considering its nanoscale microstructure.

    Science.gov (United States)

    Ghanbari, J; Naghdabadi, R

    2009-07-22

    We have used a hierarchical multiscale modeling scheme for the analysis of cortical bone considering it as a nanocomposite. This scheme consists of definition of two boundary value problems, one for macroscale, and another for microscale. The coupling between these scales is done by using the homogenization technique. At every material point in which the constitutive model is needed, a microscale boundary value problem is defined using a macroscopic kinematical quantity and solved. Using the described scheme, we have studied elastic properties of cortical bone considering its nanoscale microstructural constituents with various mineral volume fractions. Since the microstructure of bone consists of mineral platelet with nanometer size embedded in a protein matrix, it is similar to the microstructure of soft matrix nanocomposites reinforced with hard nanostructures. Considering a representative volume element (RVE) of the microstructure of bone as the microscale problem in our hierarchical multiscale modeling scheme, the global behavior of bone is obtained under various macroscopic loading conditions. This scheme may be suitable for modeling arbitrary bone geometries subjected to a variety of loading conditions. Using the presented method, mechanical properties of cortical bone including elastic moduli and Poisson's ratios in two major directions and shear modulus is obtained for different mineral volume fractions.

  13. The significance of crack-resistance curves to the mixed-mode fracture toughness of human cortical bone

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, Elizabeth A.; Launey, Maximilien E.; Ritchie, Robert O.

    2010-03-25

    The majority of fracture mechanics studies on the toughness of bone have been performed under tensile loading. However, it has recently been shown that the toughness of human cortical bone in the transverse (breaking) orientation is actually much lower in shear (mode II) than in tension (mode I); a fact that is physiologically relevant as in vivo bone is invariably loaded multiaxially. Since bone is a material that derives its fracture resistance primarily during crack growth through extrinsic toughening mechanisms, such as crack deflection and bridging, evaluation of its toughness is best achieved through measurements of the crack-resistance or R-curve, which describes the fracture toughness as a function of crack extension. Accordingly, in this study, we attempt to measure for the first time the R-curve fracture toughness of human cortical bone under physiologically relevant mixed-mode loading conditions. We show that the resulting mixed-mode (mode I + II) toughness depends strongly on the crack trajectory and is the result of the competition between the paths of maximum mechanical driving force and 'weakest' microstructural resistance.

  14. The effect of high voltage, high frequency pulsed electric field on slain ovine cortical bone.

    Science.gov (United States)

    Asgarifar, Hajarossadat; Oloyede, Adekunle; Zare, Firuz

    2014-04-01

    High power, high frequency pulsed electric fields known as pulsed power (PP) has been applied recently in biology and medicine. However, little attention has been paid to investigate the application of pulse power in musculoskeletal system and its possible effect on functional behavior and biomechanical properties of bone tissue. This paper presents the first research investigating whether or not PP can be applied safely on bone tissue as a stimuli and what will be the possible effect of these signals on the characteristics of cortical bone by comparing the mechanical properties of this type of bone pre and post expose to PP and in comparison with the control samples. A positive buck-boost converter was applied to generate adjustable high voltage, high frequency pulses (up to 500 V and 10 kHz). The functional behavior of bone in response to pulse power excitation was elucidated by applying compressive loading until failure. The stiffness, failure stress (strength) and the total fracture energy (bone toughness) were determined as a measure of the main bone characteristics. Furthermore, an ultrasonic technique was applied to determine and comprise bone elasticity before and after pulse power stimulation. The elastic property of cortical bone samples appeared to remain unchanged following exposure to pulse power excitation for all three orthogonal directions obtained from ultrasonic technique and similarly from the compression test. Nevertheless, the compressive strength and toughness of bone samples were increased when they were exposed to 66 h of high power pulsed electromagnetic field compared to the control samples. As the toughness and the strength of the cortical bone tissue are directly associated with the quality and integrity of the collagen matrix whereas its stiffness is primarily related to bone mineral content these overall results may address that although, the pulse power stimulation can influence the arrangement or the quality of the collagen network

  15. Combined treatment with GH and IGF-I: additive effect on cortical bone mass but not on linear bone growth in female rats.

    Science.gov (United States)

    Sundström, Katja; Cedervall, Therese; Ohlsson, Claes; Camacho-Hübner, Cecilia; Sävendahl, Lars

    2014-12-01

    The growth-promoting effect of combined therapy with GH and IGF-I in normal rats is not known. We therefore investigated the efficacy of treatment with recombinant human (rh)GH and/or rhIGF-I on longitudinal bone growth and bone mass in intact, prepubertal, female Sprague-Dawley rats. rhGH was injected twice daily sc (5 mg/kg·d) and rhIGF-I continuously infused sc (2.2 or 4.4 mg/kg·d) for 28 days. Longitudinal bone growth was monitored by weekly x-rays of tibiae and nose-anus length measurements, and tibial growth plate histomorphology was analyzed. Bone mass was evaluated by peripheral quantitative computed tomography. In addition, serum levels of IGF-I, rat GH, acid labile subunit, IGF binding protein-3, 150-kDa ternary complex formation, and markers of bone formation and degradation were measured. Monotherapy with rhGH was more effective than rhIGF-I (4.4 mg/kg·d) to increase tibia and nose-anus length, whereas combined therapy did not further increase tibia, or nose-anus, lengths or growth plate height. In contrast, combined rhGH and rhIGF-I (4.4 mg/kg·d) therapy had an additive stimulatory effect on cortical bone mass vs rhGH alone. Combined treatment with rhGH and rhIGF-I resulted in markedly higher serum IGF-I concentrations vs rhGH alone but did not compromise the endogenous secretion of GH. We conclude that rhIGF-I treatment augments cortical bone mass but does not further improve bone growth in rhGH-treated young, intact, female rats.

  16. Postnatal Changes in Humerus Cortical Bone Thickness Reflect the Development of Metabolic Bone Disease in Preterm Infants

    Directory of Open Access Journals (Sweden)

    Shuko Tokuriki

    2016-01-01

    Full Text Available Objective. To use cortical bone thickness (CBT of the humerus to identify risk factors for the development of metabolic bone disease in preterm infants. Methods. Twenty-seven infants born at <32 weeks of gestational age, with a birth weight of <1,500 g, were enrolled. Humeral CBT was measured from chest radiographs at birth and at 27-28, 31-32, and 36–44 weeks of postmenstrual age (PMA. The risk factors for the development of osteomalacia were statistically analyzed. Results. The humeral CBT at 36–44 weeks of PMA was positively correlated with gestational age and birth weight and negatively correlated with the duration of mechanical ventilation. CBT increased with PMA, except in six very early preterm infants in whom it decreased. Based on logistic regression analysis, gestational age and duration of mechanical ventilation were identified as risk factors for cortical bone thinning. Conclusions. Humeral CBT may serve as a radiologic marker of metabolic bone disease at 36–44 weeks of PMA in preterm infants. Cortical bones of extremely preterm infants are fragile, even when age is corrected for term, and require extreme care to lower the risk of fractures.

  17. Modalities for visualization of cortical bone remodeling: the past, present and near future

    Directory of Open Access Journals (Sweden)

    Kimberly Dawn Harrison

    2015-08-01

    Full Text Available Bone’s ability to respond to load-related phenomena and repair microdamage is achieved through the remodeling process which renews bone by activating groups of cells known as Basic Multicellular Units (BMUs. The products of BMUs, secondary osteons, have been extensively studied via classic two-dimensional (2D techniques which have provided a wealth of information on how histomorphology relates to skeletal structure and function. Remodeling is critical in maintaining healthy bone tissue; however, in osteoporotic bone imbalanced resorption results in increased bone fragility and fracture. With increasing life expectancy, such degenerative bone diseases are a growing concern. The three-dimensional (3D morphology of BMUs and their correlation to function, however, are not well characterized and little is known about the specific mechanisms that initiate and regulate their activity within cortical bone. We believe a key limitation has been the lack 3D information about BMU morphology and activity. Thus, this paper reviews methodologies for 3D investigation of cortical bone remodeling and, specifically, structures associated with BMU activity (resorption spaces and the structures they create (secondary osteons, spanning from histology to modern ex vivo imaging modalities, culminating with the growing potential of in vivo imaging. This collection of papers focuses on the theme of putting the why back into bone archytecture. Remodeling is one of two mechanisms how bone structure is dynamically modified and thus an improved 3D understanding of this fundamental process is crucial to ultimately understanding the why.

  18. Effects of deleting cannabinoid receptor-2 on mechanical and material properties of cortical and trabecular bone

    Directory of Open Access Journals (Sweden)

    Aysha B. Khalid

    2015-12-01

    Full Text Available Cnr2 is one of two cannabinoid receptors known to regulate bone metabolism. Here, we compared the whole bone properties of femora and tibiae from three-month-old Cnr2−/- mice with wild-type controls using a C57BL/6 background. Bending stiffness was measured by three-point bending. The elastic modulus, density and mineral content were measured using ultrasound, Archimedes’ principle and ashing. Micro-CT was used to measure the second moment of area, inner and outer perimeters of the cortical shaft and trabecular parameters. Deleting Cnr2 increased the bending stiffness by increasing the second moment of area. Bone from affected male mice had a greater modulus than controls, although no difference was observed in females. The fractional volume of trabecular bone was greater in Cnr2−/- females than controls, while no difference was seen in males. These data indicate that inactivating Cnr2 increases the amount of cortical bone in both males and females at 3 months of age, but the effect on trabecular bone is different in the two sexes. These findings extend previous studies looking only at trabecular bone and provide further support for the possible use of Cnr2 antagonists for improving bone properties that may be of value in the treatment of bone disorders.

  19. Implant design and its effects on osseointegration over time within cortical and trabecular bone.

    Science.gov (United States)

    Beutel, Bryan G; Danna, Natalie R; Granato, Rodrigo; Bonfante, Estevam A; Marin, Charles; Tovar, Nick; Suzuki, Marcelo; Coelho, Paulo G

    2016-08-01

    Healing chambers present at the interface between implant and bone have become a target for improving osseointegration. The objective of the present study was to compare osseointegration of several implant healing chamber configurations at early time points and regions of interest within bone using an in vivo animal femur model. Six implants, each with a different healing chamber configuration, were surgically implanted into each femur of six skeletally mature beagle dogs (n = 12 implants per dog, total n = 72). The implants were harvested at 3 and 5 weeks post-implantation, non-decalcified processed to slides, and underwent histomorphometry with measurement of bone-to-implant contact (BIC) and bone area fraction occupied (BAFO) within healing chambers at both cortical and trabecular bone sites. Microscopy demonstrated predominantly woven bone at 3 weeks and initial replacement of woven bone by lamellar bone by 5 weeks. BIC and BAFO were both significantly increased by 5 weeks (p < 0.001), and significantly higher in cortical than trabecular bone (p < 0.001). The trapezoidal healing chamber design demonstrated a higher BIC than other configurations. Overall, a strong temporal and region-specific dependence of implant osseointegration in femurs was noted. Moreover, the findings suggest that a trapezoidal healing chamber configuration may facilitate the best osseointegration. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1091-1097, 2016.

  20. Prostaglandin E2 Increased Rat Cortical Bone Mass When Administered Immediately Following Ovariectomy

    Science.gov (United States)

    Ke, Hua Zhu; Jee, Webster S.S.; Zeng, Qing Qiang; Li, Mei; Lin, Bai Yun

    1993-01-01

    To investigate the effects of ovariectomy and the simultaneous administration of prostaglandin E2 (PGE2) on rat tibial shaft cortical bone histomorphometry, thirty-five 3 month-old female Sprague-Dawley rats were either ovariectomized (OVX), or sham ovariectomy (sham-OVX). The OVX rats were divided into three groups and treated with 0, 1 and 6 mg PGE2/kg/day for 90 days. The double fluorescent labeled undecalcified tibial shaft cross sections (proximal to the tibiofibular junction) of all the subjects were used for histomorphometry analysis. No differences in cross-sectional area and cortical bone area were found between sham-OVX and OVX controls, but OVX increased marrow area, intracortical porosity area and endocortical eroded perimeter. Periosteal and endocortical bone formation rates decreased with aging yet OVX prevented these changes. These OVX-induced increases in marrow area and endocortical eroded perimeter were prevented by 1 mg PGE2/kg/day treatment and added bone to periosteal and endocortical surfaces and to the marrow cavity. At the 6 mg/kg/day dose level, PGE2-treated OVX rats increased total tissue area, cortical bone area, marrow trabmular bone area, minimal cortical width and intracortical porosity area, and decreased marrow area compared to basal, sham-OVX and OVX controls. In addition, periosteal bone formation was elevated in the 6 mg PGE2/kg/day-treated OVX rats compared to OVX controls. Endocortical eroded perimeter increased from basal and sham-OVX control levels, but decreased from OVX control levels in the 6 mg PGE2/kg/day-treated OVX rats. Our study confirmed that ovariectomy does not cause osteopenia in tibial shaft cortical bone in rats, but it does stimulate endocortical bone resorption and enlarges marrow area. The new findings from the present study demonstrate that PGE2 prevents the OVX-induced increases in endocortical bone resorption and marrow area and adds additional bone to periosteal and endocortical surfaces and to marrow

  1. Bisphosphonates improve trabecular bone mass and normalize cortical thickness in ovariectomized, osteoblast connexin43 deficient mice.

    Science.gov (United States)

    Watkins, Marcus P; Norris, Jin Yi; Grimston, Susan K; Zhang, Xiaowen; Phipps, Roger J; Ebetino, Frank H; Civitelli, Roberto

    2012-10-01

    The gap junction protein, connexin43 (Cx43) controls both bone formation and osteoclastogenesis via osteoblasts and/or osteocytes. Cx43 has also been proposed to mediate an anti-apoptotic effect of bisphosphonates, potent inhibitors of bone resorption. We studied whether bisphosphonates are effective in protecting mice with a conditional Cx43 gene deletion in osteoblasts and osteocytes (cKO) from the consequences of ovariectomy on bone mass and strength. Ovariectomy resulted in rapid loss of trabecular bone followed by a slight recovery in wild type (WT) mice, and a similar degree of trabecular bone loss, albeit slightly delayed, occurred in cKO mice. Treatment with either risedronate (20 μg/kg) or alendronate (40 μg/kg) prevented ovariectomy-induced bone loss in both genotypes. In basal conditions, bones of cKO mice have larger marrow area, higher endocortical osteoclast number, and lower cortical thickness and strength relative to WT. Ovariectomy increased endocortical osteoclast number in WT but not in cKO mice. Both bisphosphonates prevented these increases in WT mice, and normalized endocortical osteoclast number, cortical thickness and bone strength in cKO mice. Thus, lack of osteoblast/osteocyte Cx43 does not alter bisphosphonate action on bone mass and strength in estrogen deficiency. These results support the notion that one of the main functions of Cx43 in cortical bone is to restrain osteoblast and/or osteocytes from inducing osteoclastogenesis at the endocortical surface. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. The effects of glucocorticoid on microarchitecture, collagen, mineral and mechanical properties of sheep femur cortical bone.

    Science.gov (United States)

    Ding, Ming; Danielsen, Carl Christian; Overgaard, Søren

    2012-06-01

    In this study, 18 female skeletally mature sheep were randomly allocated into three groups of six each. Group 1 (glucocorticoid-1) received prednisolone treatment (0.60 mg/kg/day, five times weekly) for 7 months. Group 2 (glucocorticoid-2) received the same treatment regime followed by observation of 3 months without treatment. Group 3 was left untreated and served as controls. All sheep received a restricted diet with low calcium and phosphorus. At sacrifice, cortical bone samples from the femur midshaft of each sheep were harvested, micro-CT scanned and subjected to three-point bending and tensile strength testing. Bone collagen and mineral were determined. Cortical porosity was significantly increased in the glucocorticoid-2 compared with the glucocorticoid-1 and control groups. Apparent density was significantly decreased in the glucocorticoid-2 compared with the glucocorticoid-1 group. Collagen content was significantly increased in the glucocorticoid-2 compared with the glucocorticoid-1 and control groups. Bone mineral content did not differ between the groups. Neither the three-point bending mechanical properties nor the tensile mechanical properties differed significantly between the groups, while there was a trend towards decreasing bending mechanical properties in the glucocorticoid-2 group. In conclusion, 7 months of glucocorticoid treatment with malnutrition had a significant impact on the cortical microarchitecture of the sheep femur midshaft. These observed changes occurred 3 months after glucocorticoid cessation, suggesting a delayed effect of glucocorticoid on cortical bone. Thus, changes in cortical bone beyond cancellous bone might further increase fracture risk in patients treated with glucocorticoids. This model might be used as a glucocorticoid-induced osteoporotic model for orthopaedic biomaterial, joint prosthesis and medical device researches.

  3. Experimental and numerical analysis of Izod impact test of cortical bone tissue

    Science.gov (United States)

    Abdel-Wahab, A. A.; Silberschmidt, V. V.

    2012-05-01

    Bones can only sustain loads until a certain limit, beyond which they fail. Usually, the reasons for bone fracture are traumatic falls, sports injuries, and engagement in transport or industrial accidents. A proper treatment of bones and prevention of their fracture can be supported by in-depth understanding of deformation and fracture behavior of this tissue in such dynamic events. In this paper, a combination of experimental and numerical analysis was carried out in order to comprehend the fracture behavior of cortical bone tissue. Experimental tests were performed to study the transient dynamic behavior of cortical bone tissue under impact bending loading. The variability of absorbed energy for different cortex positions and notch depths was studied using Izod impact tests. Also, Extended Finite-Element Method implemented into the commercial finite-element software Abaqus was used to simulate the crack initiation and growth processes in a cantilever beam of cortical bone exposed to impact loading using the Izod loading scheme. The simulation results show a good agreement with the experimental data.

  4. Non-nuclear-initiated actions of the estrogen receptor protect cortical bone mass.

    Science.gov (United States)

    Bartell, Shoshana M; Han, Li; Kim, Ha-neui; Kim, Sung Hoon; Katzenellenbogen, John A; Katzenellenbogen, Benita S; Chambliss, Ken L; Shaul, Philip W; Roberson, Paula K; Weinstein, Robert S; Jilka, Robert L; Almeida, Maria; Manolagas, Stavros C

    2013-04-01

    Extensive evidence has suggested that at least some of the effects of estrogens on bone are mediated via extranuclear estrogen receptor α signaling. However, definitive proof for this contention and the extent to which such effects may contribute to the overall protective effects of estrogens on bone maintenance have remained elusive. Here, we investigated the ability of a 17β-estradiol (E2) dendrimer conjugate (EDC), incapable of stimulating nuclear-initiated actions of estrogen receptor α, to prevent the effects of ovariectomy (OVX) on the murine skeleton. We report that EDC was as potent as an equimolar dose of E2 in preventing bone loss in the cortical compartment that represents 80% of the entire skeleton, but was ineffective on cancellous bone. In contrast, E2 was effective in both compartments. Consistent with its effect on cortical bone mass, EDC partially prevented the loss of both vertebral and femoral strength. In addition, EDC, as did E2, prevented the OVX-induced increase in osteoclastogenesis, osteoblastogenesis, and oxidative stress. Nonetheless, the OVX-induced decrease in uterine weight was unaltered by EDC but was restored by E2. These results demonstrate that the protection of cortical bone mass by estrogens is mediated, at least in part, via a mechanism that is distinct from the classic mechanism of estrogen action on reproductive organs.

  5. How Tough is Human Cortical Bone? In-Situ Measurements on Realistically Short Cracks

    Energy Technology Data Exchange (ETDEWEB)

    Ritchie, Robert O; Koester, K. J.; Ager III, J. W.; Ritchie, R.O.

    2008-05-10

    Bone is more difficult to break than to split. Although this is well known, and many studies exist on the behavior of long cracks in bone, there is a need for data on the orientation-dependent crack-growth resistance behavior of human cortical bone which accurately assesses its toughness at appropriate size-scales. Here we use in-situ mechanical testing in the scanning electron microscope and x-ray computed tomography to examine how physiologically-pertinent short (<600 mu m) cracks propagate in both the transverse and longitudinal orientations in cortical bone, using both crack-deflection/twist mechanics and nonlinear-elastic fracture mechanics to determine crack-resistance curves. We find that after only 500 mu m of cracking, the driving force for crack propagation was more than five times higher in the transverse (breaking) direction than in the longitudinal (splitting) direction due to major crack deflections/twists principally at cement sheathes. Indeed, our results show that the true transverse toughness of cortical bone is far higher than previously reported. However, the toughness in the longitudinal orientation, where cracks tend to follow the cement lines, is quite low at these small crack sizes; it is only when cracks become several millimeters in length that bridging mechanisms can develop leading to the (larger-crack) toughnesses generally quoted for bone.

  6. Experimental Investigations on Microcracks in Vibrational and Conventional Drilling of Cortical Bone

    Directory of Open Access Journals (Sweden)

    Yu Wang

    2013-01-01

    Full Text Available Bone drilling is widely used in orthopedic surgery. Microcracks will be generated in bone drilling, which may cause fatigue damages and stress fractures. Fresh bovine cortical bones were drilled via vibrational and conventional ways. Drilling operations were performed by a dynamic material testing machine, which can provide the vibration while maintaining uniform feed motion. The drill site and bone debris were observed through scanning electron microscope (SEM. The experimental results showed that fewer and shorter micro-cracks were formed in vibrational drilling than those formed in conventional way. And the surface morphology of bone debris from two different drilling ways was also quite different. It is expected that vibrational drilling in orthopedic surgery operation could decrease the microdamage to the bone, which could lower the incidence of stress fracture and contribute to the postoperative recovery.

  7. Cortical and trabecular bone benefits of mechanical loading are maintained long-term in mice independent of ovariectomy

    Science.gov (United States)

    Warden, Stuart J.; Galley, Matthew R.; Hurd, Andrea L.; Richard, Jeffrey S.; George, Lydia A.; Guildenbecher, Elizabeth A.; Barker, Rick G.; Fuchs, Robyn K.

    2014-01-01

    Skeletal loading enhances cortical and trabecular bone properties. How long these benefits last following loading cessation remains an unresolved, clinically-relevant question. This study investigated long-term maintenance of loading-induced cortical and trabecular bone benefits in female C57BL/6 mice and the influence of a surgically-induced menopause on the maintenance. 16-week-old animals had their right tibia extrinsically loaded 3 days/week for 4 weeks using the mouse tibial axial compression loading model. Left tibias were not loaded and served as internal controls. Animals were subsequently detrained (restricted to cage activities) for 0, 4, 8, 26 or 52 weeks, with ovariectomy (OVX) or sham-OVX surgery being performed at 0 weeks detraining. Loading increased midshaft tibia cortical bone mass, size and strength, and proximal tibia bone volume fraction. The cortical bone mass, area and thickness benefits of loading were lost by 26 weeks of detraining due to heightened medullary expansion. However, loading-induced benefits on bone total area and strength were maintained at each detraining time point. Similarly, the benefits of loading on bone volume fraction persisted at all detraining time points. The long-term benefits of loading on both cortical and trabecular bone were not influenced by a surgically-induced menopause as there were no interactions between loading and surgery. However, OVX had independent effects on cortical bone properties at early (4 and 8 weeks) detraining time points and trabecular bone properties at all detraining time points. These cumulative data indicate loading has long-term benefits on cortical bone size and strength (but not mass) and trabecular bone morphology which are not influenced by a surgically-induced menopause. This suggests skeletal loading associated with physical activity may provide long-term benefits by preparing the skeleton to offset both the cortical and trabecular bone changes associated with aging and menopause

  8. Using smooth particle hydrodynamics to investigate femoral cortical bone remodelling at the Haversian level.

    Science.gov (United States)

    Fernandez, J W; Das, R; Cleary, P W; Hunter, P J; Thomas, C D L; Clement, J G

    2013-01-01

    In the neck of the femur, about 70% of the strength is contributed by the cortical bone, which is the most highly stressed part of the structure and is the site where failure is almost certainly initiated. A better understanding of cortical bone remodelling mechanisms can help discern changes at this anatomical site, which are essential if an understanding of the mechanisms by which hips weaken and become vulnerable to fracture is to be gained. The aims of this study were to (i) examine a hypothesis that low strain fields arise because of subject-specific Haversian canal distributions causing bone resorption and reduced bone integrity and (ii) introduce the use of a meshless particle-based computational modelling approach SPH to capture bone remodelling features at the level of the Haversian canals. We show that bone remodelling initiated by strain at the Haversian level is highly influenced by the subject-specific pore distribution, bone density, loading and osteocyte density. SPH is shown to be effective at capturing the intricate bone pore shapes that evolved over time.

  9. Measuring metacarpal cortical bone by digital x-ray radiogrammetry: a step forward?

    NARCIS (Netherlands)

    Geusens, PP; Lems, W.F.

    2009-01-01

    Changes in metacarpal cortical bone mineral density (BMD) using digital x-ray radiogrammetry were studied in patients with early rheumatoid arthritis. After 1, 2, and 5 years, large BMD losses were found: -1.7%, -2.8%, and -5.6%, respectively. Elevated erythrocyte sedimentation rate and anti-cyclic

  10. Extra-nuclear effects of estrogen on cortical bone in males require ERαAF-1

    Science.gov (United States)

    Wu, J; Gustafsson, K L; Windahl, S H; Kim, S H; Katzenellenbogen, J A; Ohlsson, C; Lagerquist, M K

    2017-01-01

    Estradiol (E2) signaling via estrogen receptor alpha (ERα) is important for the male skeleton as demonstrated by ERα inactivation in both mice and man. ERα mediates estrogenic effects not only by translocating to the nucleus and affecting gene transcription but also by extra-nuclear actions e.g., triggering cytoplasmic signaling cascades. ERα contains various domains, and the role of activation function 1 (ERαAF-1) is known to be tissue specific. The aim of this study was to determine the importance of extra-nuclear estrogen effects for the skeleton in males and to determine the role of ERαAF-1 for mediating these effects. Five-month-old male wild-type (WT) and ERαAF-1-inactivated (ERαAF-10) mice were orchidectomized and treated with equimolar doses of 17β-estradiol (E2) or an estrogen dendrimer conjugate (EDC), which is incapable of entering the nucleus and thereby only initiates extra-nuclear ER actions or their corresponding vehicles for 3.5 weeks. As expected, E2 treatment increased cortical thickness and trabecular bone volume per total volume (BV/TV) in WT males. EDC treatment increased cortical thickness in WT males, whereas no effect was detected in trabecular bone. In ERαAF-10 males, E2 treatment increased cortical thickness, but did not affect trabecular bone. Interestingly, the effect of EDC on cortical bone was abolished in ERαAF-10 mice. In conclusion, extra-nuclear estrogen signaling affects cortical bone mass in males, and this effect is dependent on a functional ERαAF-1. Increased knowledge regarding estrogen signaling mechanisms in the regulation of the male skeleton may aid the development of new treatment options for male osteoporosis. PMID:28057769

  11. Eldecalcitol improves mechanical strength of cortical bones by stimulating the periosteal bone formation in the senescence-accelerated SAM/P6 mice - a comparison with alfacalcidol.

    Science.gov (United States)

    Shiraishi, Ayako; Sakai, Sadaoki; Saito, Hitoshi; Takahashi, Fumiaki

    2014-10-01

    Eldecalcitol (ELD), a 2β-hydroxypropyloxy derivative of 1α,25(OH)2D3, is a potent inhibitor of bone resorption that has demonstrated a greater effect at reducing the risk of fracture in osteoporotic patients than alfacalcidol (ALF). In the present study, we used the senescence-accelerated mouse strain P6 (SAM/P6), which has low bone mass caused by osteoblast dysfunction, to evaluate the effect of ELD on cortical bone in comparison with ALF. Four-month-old SAM/P6 mice were given either ELD (0.025 or 0.05μg/kg) or ALF (0.2 or 0.4μg/kg) by oral gavage 5 times/week for 6 weeks. Both ELD and ALF increased serum calcium (Ca) in a dose-dependent manner. Serum Ca levels in the ELD 0.05μg/kg group were comparable to those of the ALF 0.2μg/kg group. ELD 0.05μg/kg significantly improved the bone biomechanical properties of the femur compared with the vehicle control group (pBone histomorphometry revealed that in the femoral endocortical surface, the suppression of bone resorption parameters (N.Oc/BS) and bone formation parameters (MS/BS) by ELD (0.05μg/kg) was greater than that by ALF (0.2μg/kg). In contrast, in the femoral periosteal surface, ELD 0.05μg/kg significantly increased bone formation parameters (BFR/BS, MS/BS) compared with the vehicle control group (pbone not only by inhibiting endocortical bone resorption but also by stimulating the periosteal bone formation in SAM/P6 mice. This article is part of a Special Issue entitled '16th Vitamin D Workshop'.

  12. Female Mice Lacking Estrogen Receptor-α in Hypothalamic Proopiomelanocortin (POMC) Neurons Display Enhanced Estrogenic Response on Cortical Bone Mass.

    Science.gov (United States)

    Farman, H H; Windahl, S H; Westberg, L; Isaksson, H; Egecioglu, E; Schele, E; Ryberg, H; Jansson, J O; Tuukkanen, J; Koskela, A; Xie, S K; Hahner, L; Zehr, J; Clegg, D J; Lagerquist, M K; Ohlsson, C

    2016-08-01

    Estrogens are important regulators of bone mass and their effects are mainly mediated via estrogen receptor (ER)α. Central ERα exerts an inhibitory role on bone mass. ERα is highly expressed in the arcuate (ARC) and the ventromedial (VMN) nuclei in the hypothalamus. To test whether ERα in proopiomelanocortin (POMC) neurons, located in ARC, is involved in the regulation of bone mass, we used mice lacking ERα expression specifically in POMC neurons (POMC-ERα(-/-)). Female POMC-ERα(-/-) and control mice were ovariectomized (OVX) and treated with vehicle or estradiol (0.5 μg/d) for 6 weeks. As expected, estradiol treatment increased the cortical bone thickness in femur, the cortical bone mechanical strength in tibia and the trabecular bone volume fraction in both femur and vertebrae in OVX control mice. Importantly, the estrogenic responses were substantially increased in OVX POMC-ERα(-/-) mice compared with the estrogenic responses in OVX control mice for cortical bone thickness (+126 ± 34%, P mass, ERα was silenced using an adeno-associated viral vector. Silencing of ERα in hypothalamic VMN resulted in unchanged bone mass. In conclusion, mice lacking ERα in POMC neurons display enhanced estrogenic response on cortical bone mass and mechanical strength. We propose that the balance between inhibitory effects of central ERα activity in hypothalamic POMC neurons in ARC and stimulatory peripheral ERα-mediated effects in bone determines cortical bone mass in female mice.

  13. Machining characteristics of the haversian and plexiform components of bovine cortical bone.

    Science.gov (United States)

    Conward, Michael; Samuel, Johnson

    2016-07-01

    This paper investigates the characteristic differences observed while machining the haversian and plexiform components of a bovine cortical femoral bone. To this end micro-milling slotting experiments are performed on both the components by varying both the cutting velocity and the feed-per-tooth values. The scale of machining is chosen specifically to ensure sensitivity to the microstructural variations in the bone. The material properties of the microstructural components and their size-scale relative to the feed-per-tooth values are seen to dictate the failure mechanisms encountered during machining. The cutting force, surface roughness, and tool wear are all uniquely affected by the plexiform and haversian components of the cortical bone. In general, plexiform bone requires a higher cutting force than the haversian bone. While a higher cutting velocity can lower the surface roughness of haversian bone, it typically results in the most surface damage. The cutting force and surface roughness values for both the components show strain rate sensitivity. The tool wear is seen to be the highest while cutting parallel to the lamellar structures seen in the plexiform bone.

  14. TYMPANOPLASTY WITH SEPTAL CARTILAGE AND CORTICAL MASTOID BONE IN CHOLESTEATOMA PATIENTS

    Directory of Open Access Journals (Sweden)

    Biram Singh

    2015-12-01

    Full Text Available OBJECTIVE This study was conducted to find out the ideal graft between septal cartilage and cortical mastoid bone in Farrior’s type 3 tympanoplasty in cholesteatoma patients in terms of hearing improvement, graft status and recurrence rate of the disease after canal wall down mastoidectomy. METHODS This randomized controlled trial was conducted in a tertiary care centre and the procedure and data collections were carried out for one and a half calendar year with effect from September 2007 and each case was followed up for 6 months. The data were entered and calculated statistically using SPSS16 for windows. RESULTS The study shows significant hearing improvement in both the groups. The tympanoplasty type 3 with cortical mastoid bone had air bone gap less than 20dB in 40% of patients. In septal cartilage, tympanoplasty group air bone gap less than 20dB was observed in 36.4%. Retraction of graft developed in 1(2.4% out of 20 patients among cortical mastoid bone tympanoplasty group. Among 22 patients of septal cartilage tympanoplasty type 3, 2(4.8% patients had cartilage resorption and 3(7.1% had graft displacement. Of the total 42 patients, 2(4.8% developed recurrence of the disease. CONCLUSION Cholesteatoma management is controversial. Canal wall down mastoidectomy can reduce the recurrence of disease. The cortical mastoid bone and septal cartilage grafts can provide hearing improvement after tympanoplasty type 3. There is no significant difference in hearing improvement between the two grafts.

  15. The effect of high energy shock waves focused on cortical bone: an in vitro study.

    Science.gov (United States)

    Kaulesar Sukul, D M; Johannes, E J; Pierik, E G; van Eijck, G J; Kristelijn, M J

    1993-01-01

    Extracorporeal shock wave lithotripsy has become an accepted alternative for the management of nephrolithiasis and cholelithiasis. Direct impact of shock waves cause tear and shear forces at transition sites between tissues with divergent acoustic impedances leading to stone fragmentation. The aim of this study was to determine whether shock waves can cause cortical bone damage at all and, if so, what the relationship is, if any, between the energy density of the shock waves, the number of shock waves applied, and the resulting cortical bone damage. With the Siemens Lithostar Plus with overhead module, electromagnetic shock waves, generated under water with energy densities of 0.23, 0.33, 0.42, or 0.54 mJ/mm2, corresponding with power settings 2, 4, 6, and 8, were applied to bone specimens, i.e., of rabbit femurs and tibiae. Prior to exposure to the shock waves, the bones were mounted on a specially constructed perspex holder which could be placed in a water-filled test basin with an elastic membrane in the front through which the shock waves propagate without loss of energy. This setup made it possible not only to induce complete fractures, but also to detect the existence of a linear relationship with a Spearman rank correlation coefficient of -0.72 (P < or = 0.01) between the energy level of the shock waves and the severity of the cortical bone defects. The latter findings are especially of great importance because this means that the process can be controlled and that the cortical effects will be predictable and reproducible. This study should be considered a preliminary test concerning the effects of high energy shock wave on bone.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Time Related Changes of Mineral and Collagen and Their Roles in Cortical Bone Mechanics of Ovariectomized Rabbits.

    Directory of Open Access Journals (Sweden)

    Xin-Xin Wen

    Full Text Available As cortical bone has a hierarchical structure, the macroscopic bone strength may be affected by the alterations of mineral crystal and collagen, which are main components of cortical bone. Limited studies focused on the time related alterations of these two components in osteoporosis, and their contributions to bone mechanics at tissue level and whole-bone level. Therefore, the purpose of this study was to elucidate the time related changes of mineral and collagen in cortical bone of ovariectomized (OVX rabbits, and to relate these changes to cortical bone nanomechanics and macromechanics. 40 Rabbits (7-month-old were randomly allocated into two groups (OVX and sham. OVX group received bilateral ovariectomy operation. Sham group received sham-OVX operation. Cortical bone quality of five rabbits in each group were assessed by DXA, μCT, nanoindentation, Fourier transform infrared (FTIR spectroscopy and biomechanical tests (3-point bending of femoral midshaft at pre-OVX, 4, 6, and 8 weeks after OVX. As time increased from pre-OVX to 8 weeks, the mineral to matrix ratio decreased with time, while both collagen crosslink ratio and crystallinity increased with time in OVX group. Elastic modulus and hardness measured by nanoindentation, whole-bone strength measured by biomechanical tests all decreased in OVX group with time. Bone material properties measured by FTIR correlated well with nano or whole-bone level mechanics. However, bone mineral density (BMD, structure, tissue-level and whole-bone mechanical properties did not change with age in sham group. Our study demonstrated that OVX could affect the tissue-level mechanics and bone strength of cortical bone. And this influence was attributed to the time related alterations of mineral and collagen properties, which may help us to design earlier interventions and more effective treatment strategies on osteoporosis.

  17. Safe Harvesting of Outer Table Parietal Bone Grafts Using an Oscillating Saw and a Bone Scraper : A Refinement of Technique for Harvesting Cortical and "Cancellous"-Like Calvarial Bone

    NARCIS (Netherlands)

    Schortinghuis, Jurjen; Putters, Thomas F.; Raghoebar, Gerry M.

    2012-01-01

    Calvarial bone is a readily available source of bone for preimplantation augmentation procedures of the alveolar process. However, the calvaria consist mostly of cortical bone, and cancellous bone of the diploic space is scarce. A bone scraper (Safescraper Twist; META, Reggio Emilia, Italy) was used

  18. Mesenchymal stem cells from cortical bone demonstrate increased clonal incidence, potency, and developmental capacity compared to their bone marrow–derived counterparts

    Directory of Open Access Journals (Sweden)

    Daniel Blashki

    2016-08-01

    Full Text Available In this study, we show that matrix dense cortical bone is the more potent compartment of bone than bone marrow as a stromal source for mesenchymal stem cells as isolated from adult rats. Lineage-depleted cortical bone-mesenchymal stem cells demonstrated >150-fold enrichment of colony forming unit–fibroblasts per cell incidence. compared to lineage-depleted bone marrow-mesenchymal stem cells, corresponding to a 70-fold increase in absolute recovered colony forming unit–fibroblasts. The composite phenotype Lin−/CD45−/CD31−/VLA-1+/Thy-1+ enriched for clonogenic mesenchymal stem cells solely from cortical bone–derived cells from which 70% of clones spontaneously differentiated into all lineages of bone, cartilage, and adipose. Both populations generated vascularized bone tissue within subcutaneous implanted collagen scaffolds; however, cortical bone–derived cells formed significantly more osteoid than bone marrow counterparts, quantified by histology. The data demonstrate that our isolation protocol identifies and validates mesenchymal stem cells with superior clonal, proliferative, and developmental potential from cortical bone compared to the bone marrow niche although marrow persists as the typical source for mesenchymal stem cells both in the literature and current pre-clinical therapies.

  19. Mesenchymal stem cells from cortical bone demonstrate increased clonal incidence, potency, and developmental capacity compared to their bone marrow–derived counterparts

    Science.gov (United States)

    Blashki, Daniel; Murphy, Matthew B; Ferrari, Mauro; Simmons, Paul J; Tasciotti, Ennio

    2016-01-01

    In this study, we show that matrix dense cortical bone is the more potent compartment of bone than bone marrow as a stromal source for mesenchymal stem cells as isolated from adult rats. Lineage-depleted cortical bone-mesenchymal stem cells demonstrated >150-fold enrichment of colony forming unit–fibroblasts per cell incidence. compared to lineage-depleted bone marrow-mesenchymal stem cells, corresponding to a 70-fold increase in absolute recovered colony forming unit–fibroblasts. The composite phenotype Lin−/CD45−/CD31−/VLA-1+/Thy-1+ enriched for clonogenic mesenchymal stem cells solely from cortical bone–derived cells from which 70% of clones spontaneously differentiated into all lineages of bone, cartilage, and adipose. Both populations generated vascularized bone tissue within subcutaneous implanted collagen scaffolds; however, cortical bone–derived cells formed significantly more osteoid than bone marrow counterparts, quantified by histology. The data demonstrate that our isolation protocol identifies and validates mesenchymal stem cells with superior clonal, proliferative, and developmental potential from cortical bone compared to the bone marrow niche although marrow persists as the typical source for mesenchymal stem cells both in the literature and current pre-clinical therapies. PMID:27579159

  20. Bone turnover markers are associated with higher cortical porosity, thinner cortices, and larger size of the proximal femur and non-vertebral fractures.

    Science.gov (United States)

    Shigdel, Rajesh; Osima, Marit; Ahmed, Luai A; Joakimsen, Ragnar M; Eriksen, Erik F; Zebaze, Roger; Bjørnerem, Åshild

    2015-12-01

    Bone turnover markers (BTM) predict bone loss and fragility fracture. Although cortical porosity and cortical thinning are important determinants of bone strength, the relationship between BTM and cortical porosity has, however, remained elusive. We therefore wanted to examine the relationship of BTM with cortical porosity and risk of non-vertebral fracture. In 211 postmenopausal women aged 54-94 years with non-vertebral fractures and 232 age-matched fracture-free controls from the Tromsø Study, Norway, we quantified femoral neck areal bone mineral density (FN aBMD), femoral subtrochanteric bone architecture, and assessed serum levels of procollagen type I N-terminal propeptide (PINP) and C-terminal cross-linking telopeptide of type I collagen (CTX). Fracture cases exhibited higher PINP and CTX levels, lower FN aBMD, larger total and medullary cross-sectional area (CSA), thinner cortices, and higher cortical porosity of the femoral subtrochanter than controls (p≤0.01). Each SD increment in PINP and CTX was associated with 0.21-0.26 SD lower total volumetric BMD, 0.10-0.14 SD larger total CSA, 0.14-0.18 SD larger medullary CSA, 0.13-0.18 SD thinner cortices, and 0.27-0.33 SD higher porosity of the total cortex, compact cortex, and transitional zone (all p≤0.01). Moreover, each SD of higher PINP and CTX was associated with increased odds for fracture after adjustment for age, height, and weight (ORs 1.49; 95% CI, 1.20-1.85 and OR 1.22; 95% CI, 1.00-1.49, both pfracture after accounting for FN aBMD, cortical porosity or cortical thickness (OR ranging from 1.31 to 1.39, p ranging from 0.005 to 0.028). In summary, increased BTM levels are associated with higher cortical porosity, thinner cortices, larger bone size and higher odds for fracture. We infer that this is produced by increased periosteal apposition, intracortical and endocortical remodeling; and that these changes in bone architecture are predisposing to fracture.

  1. Effects of estrogen with micronized progesterone on cortical and trabecular bone mass and microstructure in recently postmenopausal women.

    Science.gov (United States)

    Farr, Joshua N; Khosla, Sundeep; Miyabara, Yuko; Miller, Virginia M; Kearns, Ann E

    2013-02-01

    In women, cortical bone mass decreases significantly at menopause. By contrast, loss of trabecular bone begins in the third decade and accelerates after menopause. The aim of the study was to investigate the effects of estrogen on cortical and trabecular bone. The Kronos Early Estrogen Prevention Study is a double-blind, randomized, placebo-controlled trial of menopausal hormone treatment (MHT) in women, enrolled within 6-36 months of their final menstrual period. The study was conducted at the Mayo Clinic, Rochester, Minnesota. Subjects were treated with placebo (n = 31), or .45 mg/d conjugated equine estrogens (n = 20), or transdermal 50 μg/d 17β-estradiol (n = 25) with pulsed micronized progesterone. Cortical and trabecular microarchitecture at the distal radius was assessed by high-resolution peripheral quantitative computed tomography. At the distal radius, cortical volumetric bone mineral density (vBMD) decreased, and cortical porosity increased in the placebo group; MHT prevented these changes. By contrast, MHT did not prevent decreases in trabecular microarchitecture at the radius. However, MHT prevented decreases in trabecular vBMD at the thoracic spine (assessed in a subset of subjects; n = 51). These results indicate that MHT prevents deterioration in radial cortical vBMD and porosity in recently menopausal women. The maintenance of cortical bone in response to estrogen likely has important clinical implications because cortical bone morphology plays an important role in bone strength. However, effects of MHT on trabecular bone at the radius differ from those at the thoracic spine. Underlying mechanisms for these site-specific effects of MHT on cortical vs trabecular bone require further investigation.

  2. Age-related changes in collagen properties and mineralization in cancellous and cortical bone in the porcine mandibular condyle.

    Science.gov (United States)

    Willems, Nop M B K; Langenbach, Geerling E J; Everts, Vincent; Mulder, Lars; Grünheid, Thorsten; Bank, Ruud A; Zentner, Andrej; van Eijden, Theo M G J

    2010-04-01

    Collagen is an important constituent of bone, and it has been suggested that changes in collagen and mineral properties of bone are interrelated during growth. The aim of this study was to quantify age-related changes in collagen properties and the degree of mineralization of bone (DMB). The DMB in cancellous and cortical bone samples from the mandibular condyle of 35 female pigs aged 0-100 weeks was determined using micro-computed tomography. Subsequently, the amount of collagen and the number of pentosidine (Pen), hydroxylysylpyridinoline (HP), and lysylpyridinoline (LP) cross-links were quantified by means of high-performance liquid chromatography. The amount of collagen increased with age in cancellous bone but remained unchanged in cortical bone. The number of Pen and LP cross-links decreased in both bone types. In contrast, the number of HP cross-links decreased only in cancellous bone. The sum of the number of HP and LP cross-links decreased with age in cancellous bone only. The DMB increased in cancellous and cortical bone. It was concluded that the largest changes in the number of mature collagen cross-links and the mineralization in porcine cancellous and cortical bone take place before the age of 40 weeks. The low number of mature cross-links after this age suggests that the bone turnover rate continues to be high and thereby prevents the development of mature cross-links.

  3. The effects of glucocorticoid on microarchitecture, collagen, mineral and mechanical properties of sheep femur cortical bone

    DEFF Research Database (Denmark)

    Ding, Ming; Danielsen, Carl Christian; Overgaard, Søren

    2011-01-01

    of 3 months without treatment. Group 3 was left untreated and served as controls. All sheep received a restricted diet with low calcium and phosphorus. At sacrifice, cortical bone samples from the femur midshaft of each sheep were harvested, micro-CT scanned and subjected to three-point bending...... the groups, while there was a trend towards decreasing bending mechanical properties in the glucocorticoid-2 group. In conclusion, 7 months of glucocorticoid treatment with malnutrition had a significant impact on the cortical microarchitecture of the sheep femur midshaft. These observed changes occurred 3...

  4. In situ observation of fracture behavior of canine cortical bone under bending

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Zilan X. [Department of Orthopaedics, Medical University of South Carolina, 96 Jonathan Lucas Street Suite 708 MSC 622, Charleston, SC 29425 (United States); Department of Mechanical Engineering, University of South Carolina, 300 Main Street, Columbia, SC 29208 (United States); Xu, Zhi-Hui [Department of Mechanical Engineering, University of South Carolina, 300 Main Street, Columbia, SC 29208 (United States); An, Yuehuei H. [Department of Orthopaedics, Medical University of South Carolina, 96 Jonathan Lucas Street Suite 708 MSC 622, Charleston, SC 29425 (United States); Department of Orthopaedic Surgery, Southside Hospital, North Shore-LIJ Health System, 217 East Main Street, Bay Shore, NY 11706 (United States); Li, Xiaodong, E-mail: xl3p@virginia.edu [Department of Mechanical Engineering, University of South Carolina, 300 Main Street, Columbia, SC 29208 (United States); Department of Mechanical and Aerospace Engineering, University of Virginia, 122 Engineer' s Way, Charlottesville, VA 22904 (United States)

    2016-05-01

    Cortical bone provides many important body functions and maintains the rigidness and elasticity of bone. A common failure mode for bone structure is fracture under a bending force. In the current study, the fracture behavior of canine cortical bone under three-point bending was observed in situ using an atomic force microscope (AFM), a scanning electron microscope (SEM), and an optical microscope to examine the fracture process in detail. Nanoindentation was carried out to determine the elastic modulus and hardness of different building blocks of the canine cortical bone. The results have shown that the special structure of Haversian systems has significant effects on directing crack propagation. Although Haversian systems contain previously believed weak points, and micro-cracks initiate within Haversian systems, our findings have demonstrated that macro-cracks typically form around the boundaries of Haversian systems, i.e. the cement lines. Micro-cracks that developed inside Haversian systems have the functions of absorbing and dissipating energy and slow down on expanding when interstitial tissue cannot hold any more pressure, then plastic deformation and fracture occur. - Highlights: • Macro- and micro-cracks occur in unique patterns in the bone fracturing process under a bending force. • Early developed micro-cracks inside Haversian systems absorb and dissipate energy in order to delay fracture initiation. • The mechanical properties of Haverisan systems and its surrounding structures influence the developments of macro- and micro-crack formation. • Previously believed weak spots in the bone matrix are not necessarily the origins of fracture development.

  5. Cortical bone growth and maturational changes in dwarf rats induced by recombinant human growth hormone

    Science.gov (United States)

    Martinez, D. A.; Orth, M. W.; Carr, K. E.; Vanderby, R. Jr; Vailas, A. C.

    1996-01-01

    The growth hormone (GH)-deficient dwarf rat was used to investigate recombinant human (rh) GH-induced bone formation and to determine whether rhGH facilitates simultaneous increases in bone formation and bone maturation during rapid growth. Twenty dwarf rats, 37 days of age, were randomly assigned to dwarf plus rhGH (GH; n = 10) and dwarf plus vehicle (n = 10) groups. The GH group received 1.25 mg rhGH/kg body wt two times daily for 14 days. Biochemical, morphological, and X-ray diffraction measurements were performed on the femur middiaphysis. rhGH stimulated new bone growth in the GH group, as demonstrated by significant increases (P bone length (6%), middiaphyseal cross-sectional area (20%), and the amount of newly accreted bone collagen (28%) in the total pool of middiaphyseal bone collagen. Cortical bone density, mean hydroxyapatite crystal size, and the calcium and collagen contents (microgram/mm3) were significantly smaller in the GH group (P bone collagen maturation, and mean hydroxyapatite crystal size may be independently regulated during rapid growth.

  6. Effect of risedronate on the cortical and cancellous bone mass and mechanical properties in ovariectomized rats: a comparison with the effects of alfacalcidol.

    Science.gov (United States)

    Iwamoto, Jun; Seki, Azusa; Takeda, Tsuyoshi; Sato, Yoshihiro; Yamada, Harumoto; Yeh, James K

    2006-12-01

    The purpose of the present study was to compare the effects of risedronate (RIS) and alfacalcidol (ALF) on the cortical and cancellous bone mass and mechanical properties in ovariectomized rats in a head-to-head fashion. Forty female Sprague-Dawley rats, 7 mo of age, were randomized into six groups: the sham-operated control (Sham) group, and five ovariectomized groups: treated with vehicle, RIS (0.1, 1.0, or 2.5 mg/kg, p.o., daily), and ALF (0.5 microg/kg, p.o., daily). At the end of the 8-wk experimental period, bone histomorphometric analyses of the cancellous bone of the proximal tibial metaphysis and cortical bone of the tibial disphysis was performed, and the mechanical properties of the bone were evaluated at the femoral distal metaphysis (FDM) and femoral diaphysis (FD). RIS prevented the decrease in the cancellous bone volume/total tissue volume (BV/TV) noted in ovariectomized rats in a dose-dependent manner, by suppressing increases in cancellous bone formation and resorption, without any apparent effect on the Ct Ar or maximum load of the FDM or FD. On the other hand, ALF increased the cancellous BV/TV, Ct Ar, and maximum load of the FDM or FD, by mildly decreasing cancellous bone formation and resorption, increasing periosteal and endocortical bone formation, and preventing an increase in endocortical bone resorption. Thus, the present study clearly showed that RIS and ALF had differential effects on the cortical and cancellous bone mass and mechanical properties in ovariectomized rats.

  7. Cortical bone tissue resists fatigue fracture by deceleration and arrest of microcrack growth.

    Science.gov (United States)

    Akkus, O; Rimnac, C M

    2001-06-01

    Knowledge of kinetics of fatigue crack growth of microcracks is important so as to understand the dynamics of bone adaptation, remodeling, and the etiology of fatigue-based failures of cortical bone tissue. In this respect, theoretical models (Taylor, J. Biomech., 31 (1998) 587-592; Taylor and Prendergast, Proc. Instn. Mech. Engrs. Part H 211 (1997) 369-375) of microcrack growth in cortical bone have predicted a decreasing microcrack growth rate with increasing microcrack length. However, these predictions have not been observed directly. This study investigated microcrack growth and arrest through observations of surface microcracks during cyclic loading (R=0.1, 50-80MPa) of human femoral cortical bone (male, n=4, age range: 37-40yr) utilizing a video microscopy system. The change in crack length and orientation of eight surface microcracks were measured with the number of fatigue cycles from four specimens. At the applied cyclic stresses, the microcracks propagated and arrested in generally less than 10,000 cycles. The fatigue crack growth rate of all microcracks decreased with increasing crack length following initial identification, consistent with theoretical predictions. The growth rate of the microcracks was observed to be in the range of 5x10(-5) to 5x10(-7)mmcycle(-1). In addition, many of the microcracks were observed not to grow beyond 150 microm and a cyclic stress intensity factor of 0.5MNm(-3/2). The results of this study suggest that cortical bone tissue may resist fracture at the microscale by deceleration of fatigue crack growth and arrest of microcracks.

  8. Cortical and trabecular bone adaptation to incremental load magnitudes using the mouse tibial axial compression loading model.

    Science.gov (United States)

    Weatherholt, Alyssa M; Fuchs, Robyn K; Warden, Stuart J

    2013-01-01

    The mouse tibial axial compression loading model has recently been described to allow simultaneous exploration of cortical and trabecular bone adaptation within the same loaded element. However, the model frequently induces cortical woven bone formation and has produced inconsistent results with regards to trabecular bone adaptation. The aim of this study was to investigate bone adaptation to incremental load magnitudes using the mouse tibial axial compression loading model, with the ultimate goal of revealing a load that simultaneously induced lamellar cortical and trabecular bone adaptation. Adult (16 weeks old) female C57BL/6 mice were randomly divided into three load magnitude groups (5, 7 and 9N), and had their right tibia axially loaded using a continuous 2-Hz haversine waveform for 360 cycles/day, 3 days/week for 4 consecutive weeks. In vivo peripheral quantitative computed tomography was used to longitudinally assess midshaft tibia cortical bone adaptation, while ex vivo micro-computed tomography and histomorphometry were used to assess both midshaft tibia cortical and proximal tibia trabecular bone adaptation. A dose response to loading magnitude was observed within cortical bone, with increasing load magnitude inducing increasing levels of lamellar cortical bone adaptation within the upper two thirds of the tibial diaphysis. Greatest cortical bone adaptation was observed at the midshaft where there was a 42% increase in estimated mechanical properties (polar moment of inertia) in the highest (9N) load group. A dose response to load magnitude was not clearly evident within trabecular bone, with only the highest load (9N) being able to induce measureable adaptation (31% increase in trabecular bone volume fraction at the proximal tibia). The ultimate finding was that a load of 9N (engendering a tensile strain of 1833 με on medial surface of the midshaft tibia) was able to simultaneously induce measurable lamellar cortical and trabecular bone adaptation

  9. Experimental investigations of forces and torque in conventional and ultrasonically-assisted drilling of cortical bone.

    Science.gov (United States)

    Alam, K; Mitrofanov, A V; Silberschmidt, V V

    2011-03-01

    Bone drilling is widely used in orthopaedics and surgery; it is a technically demanding surgical procedure. Recent technological improvements in this area are focused on efforts to reduce forces in bone drilling. This study focuses on forces and a torque required for conventional and ultrasonically-assisted tool penetration into fresh bovine cortical bone. Drilling tests were performed with two drilling techniques, and the influence of drilling speed, feed rate and parameters of ultrasonic vibration on the forces and torque was studied. Ultrasonically-assisted drilling (UAD) was found to reduce a drilling thrust force and torque compared to conventional drilling (CD). The mechanism behind lower levels of forces and torque was explored, using high-speed filming of a drill-bone interaction zone, and was linked to the chip shape and character of its formation. It is expected that UAD will produce holes with minimal effort and avoid unnecessary damage and accompanying pain during the incision.

  10. CD44 deficiency inhibits unloading-induced cortical bone loss through downregulation of osteoclast activity.

    Science.gov (United States)

    Li, Yuheng; Zhong, Guohui; Sun, Weijia; Zhao, Chengyang; Zhang, Pengfei; Song, Jinping; Zhao, Dingsheng; Jin, Xiaoyan; Li, Qi; Ling, Shukuan; Li, Yingxian

    2015-01-01

    The CD44 is cellular surface adhesion molecule that is involved in physiological processes such as hematopoiesis, lymphocyte homing and limb development. It plays an important role in a variety of cellular functions including adhesion, migration, invasion and survival. In bone tissue, CD44 is widely expressed in osteoblasts, osteoclasts and osteocytes. However, the mechanisms underlying its role in bone metabolism remain unclear. We found that CD44 expression was upregulated during osteoclastogenesis. CD44 deficiency in vitro significantly inhibited osteoclast activity and function by regulating the NF-κB/NFATc1-mediated pathway. In vivo, CD44 mRNA levels were significantly upregulated in osteoclasts isolated from the hindlimb of tail-suspended mice. CD44 deficiency can reduce osteoclast activity and counteract cortical bone loss in the hindlimb of unloaded mice. These results suggest that therapeutic inhibition of CD44 may protect from unloading induced bone loss by inhibiting osteoclast activity.

  11. Does the cortical bone resorption rate change due to 90Sr-radiation exposure? Analysis of data from Techa Riverside residents

    Energy Technology Data Exchange (ETDEWEB)

    Tolstykh, E I; Shagina, N B; Degteva, M O; Anspaugh, L R; Napier, Bruce A

    2011-08-01

    The Mayak Production Association released large amounts of 90Sr into the Techa River (Southern Urals, Russia) with peak amounts in 1950-1951. Techa Riverside residents ingested an average of about 3,000 kBq of 90Sr. The 90Sr-body burden of approximately 15,000 individuals has been measured in the Urals Research Center for Radiation Medicine in 1974-1997 with use of a special whole-body counter (WBC). Strontium-90 had mainly deposited in the cortical part of the skeleton by 25 years following intake, and 90Sr elimination occurs as a result of cortical bone resorption. The effect of 90Sr-radiation exposure on the rate of cortical bone resorption was studied. Data on 2,022 WBC measurements were selected for 207 adult persons, who were measured three or more times before they were 50-55 years old. The individual-resorption rates were calculated with the rate of strontium recirculation evaluated as 0.0018 year-1. Individual absorbed doses in red bone marrow (RBM) and bone surface (BS) were also calculated. Statistically significant negative relationships of cortical bone resorption rate were discovered related to 90Sr-body burden and dose absorbed in the RBM or the BS. The response appears to have a threshold of about 1.5-Gy RBM dose. The radiation induced decrease in bone resorption rate may not be significant in terms of health. However, a decrease in bone remodeling rate can be among several causes of an increased level of degenerative dystrophic bone pathology in exposed persons.

  12. Guided bone regeneration (GBR) using cortical bone pins in combination with leukocyte- and platelet-rich fibrin (L-PRF).

    Science.gov (United States)

    Toffler, Michael

    2014-03-01

    Two of the fundamental requisites for guided bone regeneration (GBR) are space maintenance and primary soft-tissue closure. Allogeneic cortical bone pins measuring 2 mm in diameter in customized lengths can protect surrounding graft materials, support bioresorbable membrane barriers, and resist wound compression from the overlying soft tissues. In addition, a second-generation platelet concentrate, leukocyte- and platelet-rich fibrin (L-PRF), may be incorporated into the augmentation procedure to provide multiple growth factors, accelerate wound healing, and aid in the maintenance of primary closure over the grafted materials. Highlighting two case reports, this article features a GBR technique that uses bone pins in combination with L-PRF membranes to provide both horizontal and vertical ridge augmentation at severely compromised implant sites.

  13. Experimental multiscale measurements for the mechanical identification of a cortical bone by digital image correlation.

    Science.gov (United States)

    Nguyen, Manh-Tu; Allain, Jean-Marc; Gharbi, Hakim; Desceliers, Christophe; Soize, Christian

    2016-10-01

    The implementation of the experimental methodology by optical measurements of mechanical fields, the development of a test bench, the specimen preparation, the experimental measurements, and the digital image correlation (DIC) method, have already been the object of research in the context of biological materials. Nevertheless, in the framework of the experimental identification of a mesoscopic stochastic model of the random apparent elasticity field, measurements of one specimen is required at both the macroscopic scale and the mesoscopic scale under one single loading. The nature of the cortical bone induces some difficulties, as no single speckled pattern technique is available for simultaneously obtaining the displacement at the macroscopic scale and at the mesoscopic scale. In this paper, we present a multiscale experimental methodology based on (i) an experimental protocol for one specimen of a cortical bone, (ii) its measuring bench, (iii) optical field measurements by DIC method, (iv) the experimental results, and (v) the multiscale experimental identification by solving a statistical inverse problem.

  14. Design and validation of bending test method for characterization of miniature pediatric cortical bone specimens.

    Science.gov (United States)

    Albert, Carolyne I; Jameson, John; Harris, Gerald

    2013-02-01

    Osteogenesis imperfecta is a genetic disorder of bone fragility; however, the effects of this disorder on bone material properties are not well understood. No study has yet measured bone material strength in humans with osteogenesis imperfecta. Small bone specimens are often extracted during routine fracture surgeries in children with osteogenesis imperfecta. These specimens could provide valuable insight into the effects of osteogenesis imperfecta on bone material strength; however, their small size poses a challenge to their mechanical characterization. In this study, a validated miniature three-point bending test is described that enables measurement of the flexural material properties of pediatric cortical osteotomy specimens as small as 5 mm in length. This method was validated extensively using bovine bone, and the effect of span/depth aspect ratio (5 vs 6) on the measured flexural properties was examined. The method provided reasonable results for both Young's modulus and flexural strength in bovine bone. With a span/depth ratio of 6, the median longitudinal modulus and flexural strength results were 16.1 (range: 14.4-19.3)GPa and 251 (range: 219-293)MPa, respectively. Finally, the pilot results from two osteotomy specimens from children with osteogenesis imperfecta are presented. These results provide the first measures of bone material strength in this patient population.

  15. The effect of osteoporosis treatments on fatigue properties of cortical bone tissue

    Directory of Open Access Journals (Sweden)

    Garry R. Brock

    2015-06-01

    Full Text Available Bisphosphonates are commonly prescribed for treatment of osteoporosis. Long-term use of bisphosphonates has been correlated to atypical femoral fractures (AFFs. AFFs arise from fatigue damage to bone tissue that cannot be repaired due to pharmacologic treatments. Despite fatigue being the primary damage mechanism of AFFs, the effects of osteoporosis treatments on fatigue properties of cortical bone are unknown. To examine if fatigue-life differences occur in bone tissue after different pharmacologic treatments for osteoporosis, we tested bone tissue from the femurs of sheep given a metabolic acidosis diet to induce osteoporosis, followed by treatment with a selective estrogen reception modulator (raloxifene, a bisphosphonate (alendronate or zoledronate, or parathyroid hormone (teriparatide, PTH. Beams of cortical bone tissue were created and tested in four-point bending fatigue to failure. Tissue treated with alendronate had reduced fatigue life and less modulus loss at failure compared with other treatments, while tissue treated with PTH had a prolonged fatigue life. No loss of fatigue life occurred with zoledronate treatment despite its greater binding affinity and potency compared with alendronate. Tissue mineralization measured by microCT did not explain the differences seen in fatigue behavior. Increased fatigue life with PTH suggests that current treatment methods for AFF could have beneficial effects for restoring fatigue life. These results indicate that fatigue life differs with each type of osteoporosis treatment.

  16. On the effect of x-ray irradiation on the deformation and fracture behavior of human cortical bone

    Energy Technology Data Exchange (ETDEWEB)

    Barth, Holly D.; Launey, Maximilien E.; McDowell, Alastair A.; Ager III, Joel W.; Ritchie, Robert O.

    2010-01-10

    In situ mechanical testing coupled with imaging using high-energy synchrotron x-ray diffraction or tomography imaging is gaining in popularity as a technique to investigate micrometer and even sub-micrometer deformation and fracture mechanisms in mineralized tissues, such as bone and teeth. However, the role of the irradiation in affecting the nature and properties of the tissue is not always taken into account. Accordingly, we examine here the effect of x-ray synchrotron-source irradiation on the mechanistic aspects of deformation and fracture in human cortical bone. Specifically, the strength, ductility and fracture resistance (both work-of-fracture and resistance-curve fracture toughness) of human femoral bone in the transverse (breaking) orientation were evaluated following exposures to 0.05, 70, 210 and 630 kGy irradiation. Our results show that the radiation typically used in tomography imaging can have a major and deleterious impact on the strength, post-yield behavior and fracture toughness of cortical bone, with the severity of the effect progressively increasing with higher doses of radiation. Plasticity was essentially suppressed after as little as 70 kGy of radiation; the fracture toughness was decreased by a factor of five after 210 kGy of radiation. Mechanistically, the irradiation was found to alter the salient toughening mechanisms, manifest by the progressive elimination of the bone's capacity for plastic deformation which restricts the intrinsic toughening from the formation 'plastic zones' around crack-like defects. Deep-ultraviolet Raman spectroscopy indicated that this behavior could be related to degradation in the collagen integrity.

  17. Effect of Loading Rate and Orientation on the Compressive Response of Human Cortical Bone

    Science.gov (United States)

    2014-05-01

    Biomechanics 1975, 8, 27–40. 11. Ntim, M. M.; Bembey, A. K.; Ferguson, V. I.; Bushby, A. J. Hydration Effects on the Viscoelastic Properties of Collagen. MRS...Determination of Mechanical Properties of Human Femoral Cortical Bone by the Hopkinson Bar Stress Technique. Journal of Biomechanics 1990, 23 (11...Science and Technology 2011, 25 (9), 2211–2215. 18. Chen, W.; Song, B. Split Hopkinson (Kolsky) Bar; Springer : New York, 2010; pp 29–77. 19. Kulin, R

  18. Study of the mechanical behavior of cortical bone microstructure by the finite element method

    OpenAIRE

    Arango Villegas, Camila

    2016-01-01

    [EN] Cortical bone tissue is the responsible of giving support and structure to vertebrates. For that reason, understanding and analyzing its behavior is needed from each different hierarchical level that composes it. The lower the structural scale is, the greater the complexity and scarcity of studies in literature. These studies are relevant for understanding, preventing and solving important health problems that affect human beings. From a mechanical point of view is interesting to eval...

  19. Osteostatin-coated porous titanium can improve early bone regeneration of cortical bone defects in rats

    NARCIS (Netherlands)

    Van Der Stok, Johan; Lozano, Daniel; Chai, Yoke Chin; Amin Yavari, Saber; Bastidas Coral, Angela P.; Verhaar, Jan A N; Gómez-Barrena, Enrique; Schrooten, Jan; Jahr, Holger; Zadpoor, Amir A.; Esbrit, Pedro; Weinans, Harrie

    2015-01-01

    A promising bone graft substitute is porous titanium. Porous titanium, produced by selective laser melting (SLM), can be made as a completely open porous and load-bearing scaffold that facilitates bone regeneration through osteoconduction. In this study, the bone regenerative capacity of porous tita

  20. Investigation of hyperelastic models for nonlinear elastic behavior of demineralized and deproteinized bovine cortical femur bone.

    Science.gov (United States)

    Hosseinzadeh, M; Ghoreishi, M; Narooei, K

    2016-06-01

    In this study, the hyperelastic models of demineralized and deproteinized bovine cortical femur bone were investigated and appropriate models were developed. Using uniaxial compression test data, the strain energy versus stretch was calculated and the appropriate hyperelastic strain energy functions were fitted on data in order to calculate the material parameters. To obtain the mechanical behavior in other loading conditions, the hyperelastic strain energy equations were investigated for pure shear and equi-biaxial tension loadings. The results showed the Mooney-Rivlin and Ogden models cannot predict the mechanical response of demineralized and deproteinized bovine cortical femur bone accurately, while the general exponential-exponential and general exponential-power law models have a good agreement with the experimental results. To investigate the sensitivity of the hyperelastic models, a variation of 10% in material parameters was performed and the results indicated an acceptable stability for the general exponential-exponential and general exponential-power law models. Finally, the uniaxial tension and compression of cortical femur bone were studied using the finite element method in VUMAT user subroutine of ABAQUS software and the computed stress-stretch curves were shown a good agreement with the experimental data.

  1. Three-dimensional mapping of cortical bone thickness in subjects with different vertical facial dimensions

    Directory of Open Access Journals (Sweden)

    Mais Medhat Sadek

    2016-10-01

    Full Text Available Abstract Background The purpose of this study was to determine differences in cortical bone thickness among subjects with different vertical facial dimensions using cone beam computed tomography (CBCT. Methods From 114 pre-treatment CBCT scans, 48 scans were selected to be included in the study. CBCT-synthesized lateral cephalograms were used to categorize subjects into three groups based on their vertical skeletal pattern. Cortical bone thickness (CBT at two vertical levels (4 and 7 mm from the alveolar crest were measured in the entire tooth-bearing region in the maxilla and mandible. Results Significant group differences were detected with high-angle subjects having significantly narrower inter-radicular CBT at some sites as compared to average- and low-angle subjects. Conclusions Inter-radicular cortical bone is thinner in high-angle than in average- or low-angle subjects in few selected sites at the vertical height in which mini-implants are commonly inserted for orthodontic anchorage.

  2. Soluble VEGFR1 reverses BMP2 inhibition of intramembranous ossification during healing of cortical bone defects.

    Science.gov (United States)

    Hu, Kai; Besschetnova, Tatiana Y; Olsen, Bjorn R

    2016-09-07

    BMP2 is widely used for promotion of bone repair and regeneration. However, bone formation induced by BMP2 is quite variable. Bone forming progenitor cells in different locations appear to respond to BMP2 in different ways, and repair outcomes can vary as a consequence of modulating effects by other factors. In this study, we have examined the effects of VEGF on BMP2-induced repair of a cortical bone defect, a 1 mm diameter drill hole, in the proximal tibia of mice. Treatment of the defect with either a bolus of PBS or soluble VEGFR1 (sVEGFR1), a decoy receptor for VEGF, had the same effects on bone formation via intramembranous ossification in the defect and cartilage formation and injured periosteum, during the healing process. In contrast, treatment with BMP2 inhibited intramembranous bone formation in the defect while it promoted cartilage and endochondral bone formation in the injured periosteum compared with mice treated with PBS or sVEGFR1. The inhibitory effect of BMP2 on bone formation was unlikely due to increased osteoclast activity and decreased invasion of blood vessels in the defect. Most importantly, co-delivery of BMP2 and sVEGFR1 reversed the inhibition of intramembranous bone formation by BMP2. Furthermore, the decreased accumulation of collagen and production of bone matrix proteins in the defect of groups with BMP2 treatment could also be prevented by co-delivery of BMP2 and sVEGFR1. Our data indicate that introducing a VEGF-binding protein, such as sVEGFR1, to reduce levels of extracellular VEGF, may enhance the effects of BMP2 on intramembranous bone formation. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

  3. Variations in the vestibular cortical bone of permanent canine teeth in orthodontic patients. a comparative study: linear tomography vs. cbct (3d accuitomo).

    Science.gov (United States)

    Mateu, María E; Martínez, M E; Dagum, H; Benítez Rogé, Sandra C; Bruno, Gabriela I; Hecht, Pedro; Folco, Alejandra A

    2014-01-01

    The aim of this study was to compare the results of measuring the height of the vestibular cortical bone of canine teeth by linear tomography (LT) and 3-D Accuitomo cone beam computed tomography (CBCT) before and after aligning dental arches by orthodontic treatment. LT and CBCT were performed before and after orthodontic alignment on 12 canines in three patients undergoing orthodontic treatment, and the height of the canine vestibular cortical bones measured in mm. Measurements were taken by double-blinded operators. The mean variation in height of the vestibular cortical bone with orthodontic treatment was - 0,33 mm} 0.233 standard error using CBCT and -0,08mm } 0.55 standard error using LT. Analysis of variance (ANOVA) was performed to compare the techniques, the patients and upper and lower canines. No significant difference was found for any of the cases. Using LT to evaluate vestibular crest cortical bone in canines is comparable in efficiency to using CBCT. Height in millimeters is less in LT because image resolution is lower and when it is very thin it is not appreciable by this method.

  4. Mechanical strain, induced noninvasively in the high-frequency domain, is anabolic to cancellous bone, but not cortical bone.

    Science.gov (United States)

    Rubin, C; Turner, A S; Mallinckrodt, C; Jerome, C; McLeod, K; Bain, S

    2002-03-01

    Departing from the premise that it is the large-amplitude signals inherent to intense functional activity that define bone morphology, we propose that it is the far lower magnitude, high-frequency mechanical signals that continually barrage the skeleton during longer term activities such as standing, which regulate skeletal architecture. To examine this hypothesis, we proposed that brief exposure to slight elevations in these endogenous mechanical signals would suffice to increase bone mass in those bones subject to the stimulus. This was tested by exposing the hind limbs of adult female sheep (n = 9) to 20 min/day of low-level (0.3g), high-frequency (30 Hz) mechanical signals, sufficient to induce a peak of approximately 5 microstrain (micro epsilon) in the tibia. Following euthanasia, peripheral quantitative computed tomography (pQCT) was used to segregate the cortical shell from the trabecular envelope of the proximal femur, revealing a 34.2% increase in bone density in the experimental animals as compared with controls (p = 0.01). Histomorphometric examination of the femur supported these density measurements, with bone volume per total volume increasing by 32% (p = 0.04). This density increase was achieved by two separate strategies: trabecular spacing decreased by 36.1% (p = 0.02), whereas trabecular number increased by 45.6% (p = 0.01), indicating the formation of cancellous bone de novo. There were no significant differences in the radii of animals subject to the stimulus, indicating that the adaptive response was local rather than systemic. The anabolic potential of the signal was evident only in trabecular bone, and there were no differences, as measured by any assay, in the cortical bone. These data suggest that subtle mechanical signals generated during predominant activities such as posture may be potent determinants of skeletal morphology. Given that these strain levels are three orders of magnitude below strains that can damage bone tissue, we

  5. A mathematical model of cortical bone remodeling at cellular level under mechanical stimulus

    Institute of Scientific and Technical Information of China (English)

    Qing-Hua Qin; Ya-Nan Wang

    2012-01-01

    A bone cell population dynamics model for cortical bone remodeling under mechanical stimulus is developed in this paper.The external experiments extracted from the literature which have not been used in the creation of the model are used to test the validity of the model.Not only can the model compare reasonably well with these experimental results such as the increase percentage of final values of bone mineral content (BMC) and bone fracture energy (BFE) among different loading schemes (which proves the validity of the model),but also predict the realtime development pattern of BMC and BFE,as well as the dynamics of osteoblasts (OBA),osteoclasts (OCA),nitric oxide (NO) and prostaglandin E2 (PGE2) for each loading scheme,which can hardly be monitored through experiment.In conclusion,the model is the first of its kind that is able to provide an insight into the quantitative mechanism of bone remodeling at cellular level by which bone cells are activated by mechanical stimulus in order to start resorption/formation of bone mass.More importantly,this model has laid a solid foundation based on which future work such as systemic control theory analysis of bone remodeling under mechanical stimulus can be investigated.The to-be identified control mechanism will help to develop effective drugs and combined nonpharmacological therapies to combat bone loss pathologies.Also this deeper understanding of how mechanical forces quantitatively interact with skeletal tissue is essential for the generation of bone tissue for tissue replacement purposes in tissue engineering.

  6. Neutron activation analysis of medullar and cortical bone tissues from animals; Analise por ativacao com neutrons de tecidos osseos medular e cortical de animais

    Energy Technology Data Exchange (ETDEWEB)

    Takata, Marcelo Kazuo; Saiki, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Supervisao de Radioquimica

    2000-07-01

    In this work, neutron activation analysis was applied in the determination of the elements Ba, Br, Ca, Cl, Cr, Fe, K, Mg, Mn, Na, P, Rb, Sb, Sc, Sr and Zn present in animal bone tissues. The obtained results indicated a significant difference between the elemental concentrations present in medullar and cortical tissues. The results obtained for bone tissues from distinct animal species were also different. (author)

  7. Decreased bone turnover with balanced resorption and formation prevent cortical bone loss during disuse (hibernation) in grizzly bears (Ursus arctos horribilis).

    Science.gov (United States)

    McGee, Meghan E; Maki, Aaron J; Johnson, Steven E; Nelson, O Lynne; Robbins, Charles T; Donahue, Seth W

    2008-02-01

    Disuse uncouples bone formation from resorption, leading to increased porosity, decreased bone geometrical properties, and decreased bone mineral content which compromises bone mechanical properties and increases fracture risk. However, black bear bone properties are not adversely affected by aging despite annual periods of disuse (i.e., hibernation), which suggests that bears either prevent bone loss during disuse or lose bone and subsequently recover it at a faster rate than other animals. Here we show decreased cortical bone turnover during hibernation with balanced formation and resorption in grizzly bear femurs. Hibernating grizzly bear femurs were less porous and more mineralized, and did not demonstrate any changes in cortical bone geometry or whole bone mechanical properties compared to active grizzly bear femurs. The activation frequency of intracortical remodeling was 75% lower during hibernation than during periods of physical activity, but the normalized mineral apposition rate was unchanged. These data indicate that bone turnover decreases during hibernation, but osteons continue to refill at normal rates. There were no changes in regional variation of porosity, geometry, or remodeling indices in femurs from hibernating bears, indicating that hibernation did not preferentially affect one region of the cortex. Thus, grizzly bears prevent bone loss during disuse by decreasing bone turnover and maintaining balanced formation and resorption, which preserves bone structure and strength. These results support the idea that bears possess a biological mechanism to prevent disuse osteoporosis.

  8. Characterization of the effects of x-ray irradiation on the hierarchical structure and mechanical properties of human cortical bone

    Energy Technology Data Exchange (ETDEWEB)

    Barth, Holly; Zimmermann, Elizabeth; Schaible, Eric; Tang, Simon; Alliston, Tamara; Ritchie, Robert

    2011-08-19

    Bone comprises a complex structure of primarily collagen, hydroxyapatite and water, where each hierarchical structural level contributes to its strength, ductility and toughness. These properties, however, are degraded by irradiation, arising from medical therapy or bone-allograft sterilization. We provide here a mechanistic framework for how irradiation affects the nature and properties of human cortical bone over a range of characteristic (nano to macro) length-scales, following x-­ray exposures up to 630 kGy. Macroscopically, bone strength, ductility and fracture resistance are seen to be progressively degraded with increasing irradiation levels. At the micron-­scale, fracture properties, evaluated using in-situ scanning electron microscopy and synchrotron x-ray computed micro-tomography, provide mechanistic information on how cracks interact with the bone-matrix structure. At sub-micron scales, strength properties are evaluated with in-situ tensile tests in the synchrotron using small-/wide-angle x-ray scattering/diffraction, where strains are simultaneously measured in the macroscopic tissue, collagen fibrils and mineral. Compared to healthy bone, results show that the fibrillar strain is decreased by ~40% following 70 kGy exposures, consistent with significant stiffening and degradation of the collagen. We attribute the irradiation-­induced deterioration in mechanical properties to mechanisms at multiple length-scales, including changes in crack paths at micron-­scales, loss of plasticity from suppressed fibrillar sliding at sub-­micron scales, and the loss and damage of collagen at the nano-­scales, the latter being assessed using Raman and Fourier-Transform-Infrared spectroscopy and a fluorometric assay.

  9. Dark-field transmission electron microscopy of cortical bone reveals details of extrafibrillar crystals.

    Science.gov (United States)

    Schwarcz, Henry P; McNally, Elizabeth A; Botton, Gianluigi A

    2014-12-01

    In a previous study we showed that most of the mineral in bone is present in the form of "mineral structures", 5-6nm-thick, elongated plates which surround and are oriented parallel to collagen fibrils. Using dark-field transmission electron microscopy, we viewed mineral structures in ion-milled sections of cortical human bone cut parallel to the collagen fibrils. Within the mineral structures we observe single crystals of apatite averaging 5.8±2.7nm in width and 28±19nm in length, their long axes oriented parallel to the fibril axis. Some appear to be composite, co-aligned crystals as thin as 2nm. From their similarity to TEM images of crystals liberated from deproteinated bone we infer that we are viewing sections through platy crystals of apatite that are assembled together to form the mineral structures.

  10. Cluster analysis of infrared spectra of rabbit cortical bone samples during maturation and growth.

    Science.gov (United States)

    Kobrina, Yevgeniya; Turunen, Mikael J; Saarakkala, Simo; Jurvelin, Jukka S; Hauta-Kasari, Markku; Isaksson, Hanna

    2010-12-01

    Bone consists of an organic and an inorganic matrix. During development, bone undergoes changes in its composition and structure. In this study we apply three different cluster analysis algorithms [K-means (KM), fuzzy C-means (FCM) and hierarchical clustering (HCA)], and discriminant analysis (DA) on infrared spectroscopic data from developing cortical bone with the aim of comparing their ability to correctly classify the samples into different age groups. Cortical bone samples from the mid-diaphysis of the humerus of New Zealand white rabbits from three different maturation stages (newborn (NB), immature (11 days-1 month old), mature (3-6 months old)) were used. Three clusters were obtained by KM, FCM and HCA methods on different spectral regions (amide I, phosphate and carbonate). The newborn samples were well separated (71-100% correct classifications) from the other age groups by all bone components. The mature samples (3-6 months old) were well separated (100%) from those of other age groups by the carbonate spectral region, while by the phosphate and amide I regions some samples were assigned to another group (43-71% correct classifications). The greatest variance in the results for all algorithms was observed in the amide I region. In general, FCM clustering performed better than the other methods, and the overall error was lower. The discriminate analysis results showed that by combining the clustering results from all three spectral regions, the ability to predict the correct age group for all samples increased (from 29-86% to 77-91%). This study is the first to compare several clustering methods on infrared spectra of bone. Fuzzy C-means clustering performed best, and its ability to study the degree of memberships of samples to each cluster might be beneficial in future studies of medical diagnostics.

  11. Selective laser melting-produced porous titanium scaffolds regenerate bone in critical size cortical bone defects

    NARCIS (Netherlands)

    J. van der Stok (Johan); O.P. van der Jagt (Olav); S. Amin Yavari (Saber); M.F.P. de Haas (Mirthe); J.H. Waarsing (Jan); H. Jahr (Holger); E.M.M. van Lieshout (Esther); P. Patka (Peter); J.A.N. Verhaar (Jan); A.A. Zadpoor (Amir Abbas); H.H. Weinans (Harrie)

    2013-01-01

    textabstractPorous titanium scaffolds have good mechanical properties that make them an interesting bone substitute material for large bone defects. These scaffolds can be produced with selective laser melting, which has the advantage of tailoring the structure's architecture. Reducing the strut siz

  12. The relationship between the mechanical anisotropy of human cortical bone tissue and its microstructure

    Science.gov (United States)

    Espinoza Orias, Alejandro A.

    Orthopedics research has made significant advances in the areas of biomechanics, bone implants and bone substitute materials. However, to date there is no definitive model to explain the structure-property relationships in bone as a material to enable better implant designs or to develop a true biomechanical analog of bone. The objective of this investigation was to establish a relationship between the elastic anisotropy of cortical bone tissue and its microstructure. Ultrasonic wave propagation was used to measure stiffness coefficients for specimens sectioned along the length of a human femur. The elastic constants were orthotropic and varied with anatomical location. Stiffness coefficients were generally largest at the midshaft and stiffness anisotropy ratios were largest at the distal and proximal ends. These tests were run on four additional human femurs to assess the influence of phenotypic variation, and in most cases, it was found that phenotypes do not exert a significant effect. Stiffness coefficients were shown to be correlated as a power law relation to apparent density, but anisotropy ratios were not. Texture analysis was performed on selected samples to measure the orientation distribution of the bone mineral crystals. Inverse pole figures showed that bone mineral crystals had a preferred crystallographic orientation, coincident with the long axis of the femur, which is its principal loading direction. The degree of preferred orientation was represented in Multiples of a Random Distribution (MRD), and correlated to the anisotropy ratios. Variation in elastic anisotropy was shown to be primarily due to the bone mineral orientation. The results found in this work can be used to incorporate anisotropy into structural analysis for bone as a material.

  13. In Vitro Fracture of Human Cortical Bone: Local Fracture Criteria and Toughening Mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Nalla, R; Stolken, J; Kinney, J; Ritchie, R

    2004-08-18

    A micro-mechanistic understanding of bone fracture that encompasses how cracks interact with the underlying microstructure and defines their local failure mode is lacking, despite extensive research on the response of bone to a variety of factors like aging, loading, and/or disease. Micro-mechanical models for fracture incorporating such local failure criteria have been widely developed for metallic and ceramic materials systems; however, few such deliberations have been undertaken for the fracture of bone. In fact, although the fracture event in mineralized tissues such as bone is commonly believed to be locally strain controlled, until recently there has been little experimental evidence to support this widely held belief. In the present study, a series of in vitro experiments involving a double-notch bend test geometry are performed in order to shed further light on the nature of the local cracking events that precede catastrophic fracture in bone and to define their relationship to the microstructure. Specifically, crack-microstructure interactions are examined to determine the salient toughening mechanisms in human cortical bone and to characterize how these may affect the anisotropy in fracture properties. Based on preliminary micro-mechanical models of these processes, in particular crack deflection and uncracked ligament bridging, the relative importance of these toughening mechanisms is established.

  14. Development of new criteria for cortical bone histomorphometry in femoral neck: intra- and inter-observer reproducibility.

    Science.gov (United States)

    Tong, Xiao-Yu; Malo, Markus; Tamminen, Inari S; Isaksson, Hanna; Jurvelin, Jukka S; Kröger, Heikki

    2015-01-01

    Histomorphometry is commonly applied to study bone remodeling. Histological definitions of cortical bone boundaries have not been consistent. In this study, new criteria for specific definition of the transitional zone between the cortical and cancellous bone in the femoral neck were developed. The intra- and inter-observer reproducibility of this method was determined by quantitative histomorphometry and areal overlapping analysis. The undecalcified histological sections of femoral neck specimens (n = 6; from men aged 17-59 years) were processed and scanned to acquire histological images of complete bone sections. Specific criteria were applied to define histological boundaries. "Absolute cortex area" consisted of pure cortical bone tissue only, and was defined mainly based on the size of composite canals and their distance to an additional "guide" boundary (so-called "preliminary cortex boundary," the clear demarcation line of density between compact cortex and sparse trabeculae). Endocortical bone area was defined by recognizing characteristic endocortical structures adjacent to the preliminary cortical boundary. The present results suggested moderate to high reproducibility for low-magnification parameters (e.g., cortical bone area). The coefficient of variation (CV %) ranged from 0.02 to 5.61 in the intra-observer study and from 0.09 to 16.41 in the inter-observer study. However, the intra-observer reproducibility of some high-magnification parameters (e.g., osteoid perimeter/endocortical perimeter) was lower (CV %, 0.33-87.9). The overlapping of three histological areas in repeated analyses revealed highest intra- and inter-observer reproducibility for the absolute cortex area. This study provides specific criteria for the definition of histological boundaries for femoral neck bone specimens, which may aid more precise cortical bone histomorphometry.

  15. Remodeling of heat-treated cortical bone allografts for posterior lumbar interbody fusion: serial 10-year follow-up.

    Science.gov (United States)

    Muramatsu, Koichi; Hachiya, Yudo; Izawa, Hiroyuki; Yamada, Harumoto

    2012-12-01

    We have selected heat-treated bone allografts as the graft material since the Tokai Bone Bank, the first regional bone bank in Japan, was established in 1992. In this study, we examined changes in bone mineral density (BMD), and morphology observed by magnetic resonance imaging (MRI), and histological findings of bone grafts in cases followed up for 7-10 years after bone grafting to grasp the remodeling of heat-treated cortical bone allografts for posterior lumber interbody fusion (PLIF). BMD of bone grafts was reduced by half at 10 years after grafting. MRI revealed that bone grafts were indistinguishable initially in only 22.2% of cases, whereas after a lengthy period of 10 years distinguishable in many cases. Histologically, new bone formation at the graft-host interface was observed earlier, at 1 year after grafting, than that at the periphery of canals in the specimens. The laminated structure of the cortical bone eroded over time, and fragmented bone trabeculae were observed in the specimens at 8 years or longer after grafting, though necrotic bone still remained in some sites.

  16. Influence of short-term fixation with mixed formalin or ethanol solution on the mechanical properties of human cortical bone

    Directory of Open Access Journals (Sweden)

    Mick E.

    2015-09-01

    Full Text Available Bone specimens obtained for biomechanical experiments are fresh-frozen for storage to slow down tissue degradation and autolysis in long-term storage. Alternatively, due to infectious risks related to the fresh tissues, fixative agents are commonly used. However, fixatives will likely change the mechanical properties of bone. Existing studies on this issue gave controversial results that are hardly comparable due to a variety of measurement approaches. For this reason, the influence of ethanol and a formalin-based fixative agent was evaluated on the mechanical properties of human cortical bone specimens by means of four-point-bending tests. 127 prismatic specimens with rectangular cross sections (2.5 x 2.5 x 20 mm3 were obtained from different regions of two fresh human femora (medial, lateral, dorsal, ventral. Specimens were either fixed in ethanol or in a mixed formalin solution or frozen following a given scheme. After two weeks of storage the samples were re-hydrated in isotonic saline and subsequently tested mechanically. The elastic bending modulus and ultimate bending strength were computed considering the actual dimensions of each specific specimen. For statistical analysis a one-way-ANOVA and an LSD post-hoc-test were performed. For ultimate bending strength no significant differences due to formalin or ethanol fixation, as compared to unfixed-fresh bone specimens could be found. And only for few cases significant differences in elastic bending modulus were observed when the two bones were evaluated separately. Since more differences of significant level due to the anatomical region of the samples were determined, the original location seems to have more influence on the evaluated mechanical properties than the method of (chemical fixation. Consequently, ethanol and the mixed formalin solution can be recommended as a fixation agent for samples in biomechanical testing, if these samples are rinsed in isotonic saline prior to static

  17. Radiological and Clinical Evaluation of the Transosseous Cortical Button Technique in Distal Biceps Tendon Repair.

    Science.gov (United States)

    Caekebeke, Pieter; Vermeersch, Nicolas; Duerinckx, Joris; van Riet, Roger

    2016-12-01

    One of the options to repair a ruptured distal biceps tendon to the radial tuberosity is by means of a transosseous cortical button. Although excellent functional outcomes have been reported, no studies have been performed to quantify the effect of the transosseous fixation technique on the radius. Our study evaluated the clinical outcome and radiological outcome of this technique. The main goal of this study was to evaluate the radiographic evolution of the bone tunnel in the radius. Patients with an acute distal biceps tendon rupture treated with a transosseous cortical button were invited to take part in the study. Fourteen patients were included in the final analysis. All patients were evaluated both clinically and by computed tomography scanning of the proximal radius after a minimum follow-up of 2 years. Outcomes were recorded using the visual analog scale score for pain, the Mayo Elbow Performance Score, and Disabilities of the Arm, Shoulder, and Hand scores. Bone tunnel volume was measured with semiautomated computed tomography segmentation using image-processing software. There were no failures of fixation in the patient group examined. Elbow mobility, arm, and forearm circumference were symmetric for all patients. Average visual analog scale for pain was less than 2. Mean Disabilities of the Arm, Shoulder, and Hand score and Mayo Elbow Performance Score were 2.3 and 97.6, respectively. Computed tomography images showed an average closure of the radial bony tunnel of 64% of the initial volume. Biceps tendon repair with cortical button fixation only shows partial tunnel closure. This could reduce the risk of potential complications due to osteolysis, such as radius fracture or hardware failure. Functional results were excellent and comparable to other fixation methods. The role of interference screws in transosseous cortical button techniques to strengthen the repair and to avoid osteolysis may therefore be questioned. Therapeutic IV. Copyright © 2016

  18. Magnetization transfer contrast imaging in bovine and human cortical bone applying an ultrashort echo time sequence at 3 Tesla.

    Science.gov (United States)

    Springer, Fabian; Martirosian, Petros; Machann, Jürgen; Schwenzer, Nina F; Claussen, Claus D; Schick, Fritz

    2009-05-01

    Magnetization transfer (MT) contrast imaging reveals interactions between free water molecules and macromolecules in a variety of tissues. The introduction of ultrashort echo time (UTE) sequences to clinical whole-body MR scanners expands the possibility of MT imaging to tissues with extremely fast signal decay such as cortical bone. The aim of this study was to investigate the MT effect of bovine cortical bone in vitro on a 3 Tesla whole-body MR unit. A 3D-UTE sequence with a rectangular-shaped on-resonant excitation pulse and a Gaussian-shaped off-resonant saturation pulse for MT preparation was applied. The flip angle and off-resonance frequency of the MT pulse was systematically varied. Measurements on various samples of bovine cortical bone, agar gel, aqueous manganese chloride solutions, and solid polymeric materials (polyurethane) were performed, followed by preliminary applications on human tibial bone in vivo. Direct on-resonant saturation effects of the MT prepulses were calculated numerically by means of Bloch's equations. Corrected for direct saturation effects dry and fresh bovine cortical bone showed "true" MTR values of 0.26 and 0.21, respectively. In vivo data were obtained from three healthy subjects and showed MTR values of 0.30 +/- 0.08. In vivo studies into MT of cortical bone might have the potential to give new insights in musculoskeletal pathologies.

  19. Glycation of human cortical and cancellous bone captures differences in the formation of Maillard reaction products between glucose and ribose.

    Science.gov (United States)

    Sroga, Grażyna E; Siddula, Alankrita; Vashishth, Deepak

    2015-01-01

    To better understand some aspects of bone matrix glycation, we used an in vitro glycation approach. Within two weeks, our glycation procedures led to the formation of advanced glycation end products (AGEs) at the levels that corresponded to approx. 25-30 years of the natural in vivo glycation. Cortical and cancellous bones from human tibias were glycated in vitro using either glucose (glucosylation) or ribose (ribosylation). Both glucosylation and ribosylation led to the formation of higher levels of AGEs and pentosidine (PEN) in cancellous than cortical bone dissected from all tested donors (young, middle-age and elderly men and women). More efficient glycation of bone matrix proteins in cancellous bone most likely depended on the higher porosity of this tissue, which facilitated better accessibility of the sugars to the matrix proteins. Notably, glycation of cortical bone from older donors led to much higher AGEs levels as compared to young donors. Such efficient in vitro glycation of older cortical bone could result from aging-related increase in porosity caused by the loss of mineral content. In addition, more pronounced glycation in vivo would be driven by elevated oxidation processes. Interestingly, the levels of PEN formation differed pronouncedly between glucosylation and ribosylation. Ribosylation generated very high levels of PEN (approx. 6- vs. 2.5-fold higher PEN level than in glucosylated samples). Kinetic studies of AGEs and PEN formation in human cortical and cancellous bone matrix confirmed higher accumulation of fluorescent crosslinks for ribosylation. Our results suggest that in vitro glycation of bone using glucose leads to the formation of lower levels of AGEs including PEN, whereas ribosylation appears to support a pathway toward PEN formation. Our studies may help to understand differences in the progression of bone pathologies related to protein glycation by different sugars, and raise awareness for excessive sugar supplementation in food and

  20. Selective laser melting-produced porous titanium scaffolds regenerate bone in critical size cortical bone defects.

    Science.gov (United States)

    Van der Stok, Johan; Van der Jagt, Olav P; Amin Yavari, Saber; De Haas, Mirthe F P; Waarsing, Jan H; Jahr, Holger; Van Lieshout, Esther M M; Patka, Peter; Verhaar, Jan A N; Zadpoor, Amir A; Weinans, Harrie

    2013-05-01

    Porous titanium scaffolds have good mechanical properties that make them an interesting bone substitute material for large bone defects. These scaffolds can be produced with selective laser melting, which has the advantage of tailoring the structure's architecture. Reducing the strut size reduces the stiffness of the structure and may have a positive effect on bone formation. Two scaffolds with struts of 120-µm (titanium-120) or 230-µm (titanium-230) were studied in a load-bearing critical femoral bone defect in rats. The defect was stabilized with an internal plate and treated with titanium-120, titanium-230, or left empty. In vivo micro-CT scans at 4, 8, and 12 weeks showed more bone in the defects treated with scaffolds. Finally, 18.4 ± 7.1 mm(3) (titanium-120, p = 0.015) and 18.7 ± 8.0 mm(3) (titanium-230, p = 0.012) of bone was formed in those defects, significantly more than in the empty defects (5.8 ± 5.1 mm(3) ). Bending tests on the excised femurs after 12 weeks showed that the fusion strength reached 62% (titanium-120) and 45% (titanium-230) of the intact contralateral femurs, but there was no significant difference between the two scaffolds. This study showed that in addition to adequate mechanical support, porous titanium scaffolds facilitate bone formation, which results in high mechanical integrity of the treated large bone defects.

  1. Effects of Loading Duration and Short Rest Insertion on Cancellous and Cortical Bone Adaptation in the Mouse Tibia.

    Science.gov (United States)

    Yang, Haisheng; Embry, Rachel E; Main, Russell P

    2017-01-01

    The skeleton's osteogenic response to mechanical loading can be affected by loading duration and rest insertion during a series of loading events. Prior animal loading studies have shown that the cortical bone response saturates quickly and short rest insertions between load cycles can enhance cortical bone formation. However, it remains unknown how loading duration and short rest insertion affect load-induced osteogenesis in the mouse tibial compressive loading model, and particularly in cancellous bone. To address this issue, we applied cyclic loading (-9 N peak load; 4 Hz) to the tibiae of three groups of 16 week-old female C57BL/6 mice for two weeks, with a different number of continuous load cycles applied daily to each group (36, 216 and 1200). A fourth group was loaded under 216 daily load cycles with a 10 s rest insertion after every fourth cycle. We found that as few as 36 load cycles per day were able to induce osteogenic responses in both cancellous and cortical bone. Furthermore, while cortical bone area and thickness continued to increase through 1200 cycles, the incremental increase in the osteogenic response decreased as load number increased, indicating a reduced benefit of the increasing number of load cycles. In the proximal metaphyseal cancellous bone, trabecular thickness increased with load up to 216 cycles. We also found that insertion of a 10 s rest between load cycles did not improve the osteogenic response of the cortical or cancellous tissues compared to continuous loading in this model given the age and sex of the mice and the loading parameters used here. These results suggest that relatively few load cycles (e.g. 36) are sufficient to induce osteogenic responses in both cortical and cancellous bone in the mouse tibial loading model. Mechanistic studies using the mouse tibial loading model to examine bone formation and skeletal mechanobiology could be accomplished with relatively few load cycles.

  2. Time-lapsed assessment of microcrack initiation and propagation in murine cortical bone at submicrometer resolution.

    Science.gov (United States)

    Voide, R; Schneider, P; Stauber, M; Wyss, P; Stampanoni, M; Sennhauser, U; van Lenthe, G H; Müller, R

    2009-08-01

    The strength of bone tissue is not only determined by its mass, but also by other properties usually referred to as bone quality, such as microarchitecture, distribution of bone cells, or microcracks and damage. It has been hypothesized that the bone ultrastructure affects microcrack initiation and propagation. Due to its high resolution, bone assessment by means of synchrotron radiation (SR)-based computed tomography (CT) allows unprecedented three-dimensional (3D) and non-invasive insights into ultrastructural bone phenotypes, such as the canal network and the osteocyte lacunar system. The aims of this study were to describe the initiation and propagation of microcracks and their relation with these ultrastructural phenotypes. To this end, femora from the two genetically distinct inbred mouse strains C3H/He (C3H) and C57BL/6 (B6) were loaded axially under compression, from 0% strain to failure, with 1% strain steps. Between each step, a high-resolution 3D image (700 nm nominal resolution) was acquired at the mid-diaphysis using SR CT for characterization and quantitative analysis of the intracortical porosity, namely the bone canal network, the osteocyte lacunar system and the emerging microcracks. For C3H mice, the canal, lacunar, and microcrack volume densities accounted typically for 1.91%, 2.11%, and 0.27% of the cortical total volume at 2% apparent strain, respectively. Due to its 3D nature, SR CT allowed to visualize and quantify also the volumetric extent of microcracks. At 2% apparent strain, the average microcrack thickness for both mouse strains was 2.0 microm for example. Microcracks initiated at canal and at bone surfaces, whereas osteocyte lacunae provided guidance to the microcracks. Moreover, we observed that microcracks could appear as linear cracks in one plane, but as diffuse cracks in a perpendicular plane. Finally, SR CT images permitted visualization of uncracked ligament bridging, which is thought to be of importance in bone toughening

  3. Hydration and radiation effects on the residual stress state of cortical bone.

    Science.gov (United States)

    Tung, Patrick K M; Mudie, Stephen; Daniels, John E

    2013-12-01

    The change in the biaxial residual stress state of hydroxyapatite crystals and collagen fibrillar structure in sections of bovine cortical bone has been investigated as a function of dehydration and radiation dose using combined small- and wide-angle X-ray scattering. It is shown that dehydration of the bone has a pronounced effect on the residual stress state of the crystalline phase, while the impact of radiation damage alone is less dramatic. In the initial hydrated state, a biaxial compressive stress of approximately -150 MPa along the bone axis exists in the hydroxyapatite crystals. As water evaporates from the bone material, the stress state moves to a tensile state of approximately 100 MPa. The collagen fibrillar structure is initially in a tensile residual stress state when the bone is hydrated and the state increases in magnitude slightly with dehydration. Radiation dose in continually hydrated samples also reduces the initial biaxial compressive stress magnitude in the hydroxyapatite phase; however, the stress remains compressive. Radiation exposure alone does not appear to affect the stress state of the collagen fibrillar structure.

  4. Analysis of forces in conventional and ultrasonically assisted plane cutting of cortical bone.

    Science.gov (United States)

    Alam, Khurshid; Khan, Mushtaq; Silberschmidt, Vadim V

    2013-06-01

    Bone cutting is a well accepted but technically demanding surgical procedure in orthopaedics. A level of tool penetration force during cutting of bones has been the prime concern to surgeons, since it can produce unnecessary mechanical damage to surrounding tissues. Research in this area has been undertaken for many decades to find ways to minimise the cutting force. Cutting of bone with ultrasonic tools is a relatively new technique replacing conventional procedures in neuro-, dental and orthopaedic surgeries, due to its precision and safety. In this article, the level of forces produced during a chisel-like tool penetration in a fresh cortical bone is studied. The obtained force data are analysed for both conventional cutting and ultrasonically assisted cutting. Through a series of experiments, it was demonstrated that the depth of cut and parameters of ultrasonic oscillations affected the level of cutting force, the former being the main factor in both types of cutting. It was found that the tool penetration force was decreased with an increase in the ultrasonic frequency or amplitude and was not affected by the cutting speed. The rise in bone temperature was measured and was found to be insensitive to the level of cutting speed within the range used in this study.

  5. Novel anatomic adaptation of cortical bone to meet increased mineral demands of reproduction.

    Science.gov (United States)

    Macica, Carolyn M; King, Helen E; Wang, Meina; McEachon, Courtney L; Skinner, Catherine W; Tommasini, Steven M

    2016-04-01

    The goal of this study was to investigate the effects of reproductive adaptations to mineral homeostasis on the skeleton in a mouse model of compromised mineral homeostasis compared to adaptations in control, unaffected mice. During pregnancy, maternal adaptations to high mineral demand include more than doubling intestinal calcium absorption by increasing calcitriol production. However, calcitriol biosynthesis is impaired in HYP mice, a murine model of X-linked hypophosphatemia (XLH). In addition, there is a paucity of mineralized trabecular bone, a primary target of bone resorption during pregnancy and lactation. Because the highest density of mineral is in mature cortical bone, we hypothesized that mineral demand is met by utilizing intracortical mineral reserves. Indeed, analysis of HYP mice revealed dramatic increases in intracortical porosity characterized by elevated serum PTH and type-I collagen matrix-degrading enzyme MMP-13. We discovered an increase in carbonate ion substitution in the bone mineral matrix during pregnancy and lactation of HYP mice, suggesting an alternative mechanism of bone remodeling that maintains maternal bone mass during periods of high mineral demand. This phenomenon is not restricted to XLH, as increased carbonate in the mineral matrix also occurred in wild-type mice during lactation. Taken together, these data suggest that increased intracortical perilacunar mineral turnover also contributes to maintaining phosphate levels during periods of high mineral demand. Understanding the mechanisms of skeletal contribution to mineral homeostasis is important to improving the treatment and prevention of fracture risk and bone fragility for female patients with XLH, but also provides important insight into the role and unique adaptations of the maternal skeleton to the demands of fetal development and the needs of postnatal nutrition. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Elastic modulus and hardness of cortical and trabecular bovine bone measured by nanoindentation

    Institute of Scientific and Technical Information of China (English)

    WANG X J; CHEN X B; HODGSON P D; WEN C E

    2006-01-01

    The elastic modulus and hardness of several microstructure components of dry bovine vertebrae and tibia have been investigated in the longitude and transverse directions using nanoindentation. The elastic modulus for the osteons and the interstitial lamellae in the longitude direction were found to be (24.7±2.5) GPa and (30.1±2.4) GPa. As it's difficult to distinguish osteons from interstitial lamellae in the transverse direction,the average elastic modulus for cortical bovine bone in the transverse direction was (19.8±1.6) GPa. The elastic modulus for trabecular bone in the longitude and transverse direction were (20±2) GPa and (14.7±1.9) GPa respectively. The hardness also varied among the microstructure components in the range of 0.41-0.89 GPa. Analyses of variance show that the values are significantly different.

  7. NPY neuron-specific Y2 receptors regulate adipose tissue and trabecular bone but not cortical bone homeostasis in mice.

    Directory of Open Access Journals (Sweden)

    Yan-Chuan Shi

    Full Text Available BACKGROUND: Y2 receptor signalling is known to be important in neuropeptide Y (NPY-mediated effects on energy homeostasis and bone physiology. Y2 receptors are located post-synaptically as well as acting as auto receptors on NPY-expressing neurons, and the different roles of these two populations of Y2 receptors in the regulation of energy homeostasis and body composition are unclear. METHODOLOGY/PRINCIPAL FINDINGS: We thus generated two conditional knockout mouse models, Y2(lox/lox and NPYCre/+;Y2(lox/lox, in which Y2 receptors can be selectively ablated either in the hypothalamus or specifically in hypothalamic NPY-producing neurons of adult mice. Specific deletion of hypothalamic Y2 receptors increases food intake and body weight compared to controls. Importantly, specific ablation of hypothalamic Y2 receptors on NPY-containing neurons results in a significantly greater adiposity in female but not male mice, accompanied by increased hepatic triglyceride levels, decreased expression of liver carnitine palmitoyltransferase (CPT1 and increased expression of muscle phosphorylated acetyl-CoA carboxylase (ACC. While food intake, body weight, femur length, bone mineral content, density and cortical bone volume and thickness are not significantly altered, trabecular bone volume and number were significantly increased by hypothalamic Y2 deletion on NPY-expressing neurons. Interestingly, in situ hybridisation reveals increased NPY and decreased proopiomelanocortin (POMC mRNA expression in the arcuate nucleus of mice with hypothalamus-specific deletion of Y2 receptors in NPY neurons, consistent with a negative feedback mechanism between NPY expression and Y2 receptors on NPY-ergic neurons. CONCLUSIONS/SIGNIFICANCE: Taken together these data demonstrate the anti-obesogenic role of Y2 receptors in the brain, notably on NPY-ergic neurons, possibly via inhibition of NPY neurons and concomitant stimulation of POMC-expressing neurons in the arcuate nucleus of

  8. Organ and tissue level properties are more sensitive to age than osteocyte lacunar characteristics in rat cortical bone

    DEFF Research Database (Denmark)

    Wittig, Nina; Bach-Gansmo, Fiona Linnea; Birkbak, Mie Elholm

    2016-01-01

    lacunar properties in rat cortical bone. Femora of 14 to 42-week-old female Wistar rats were investigated using multiple complementary techniques including X-ray micro-computed tomography and biomechanical testing. The body weight, femoral length, aBMD, load to fracture, tissue volume, bone volume......, and tissue density were found to increase rapidly with age at 14–30 weeks. At the age of 30–42 weeks, the growth rate appeared to decrease. However, no accompanying changes were found in osteocyte lacunar properties such as lacunar volume, ellipsoidal radii, lacunar stretch, lacunar oblateness, or lacunar...... orientation with animal age. Hence, the evolution of organ and tissue level properties with age in rat cortical bone is not accompanied by related changes in osteocyte lacunar properties. This suggests that bone microstructure and bone matrix material properties and not the geometric properties...

  9. EFFECTS OF CHEMICAL PROCESSING AND OXIDE ETHYLENE STERILIZATION ON CORTICAL AND CANCELLOUS RAT BONE: A LIGHT AND ELECTRON SCANNING MICROSCOPY STUDY.

    Science.gov (United States)

    Castiglia, Marcello Teixeira; da Silva, Juliano Voltarelli F; Frezarim Thomazini, José Armendir; Volpon, José Batista

    2009-01-01

    To evaluate, under microscopic examination, the structural changes displayed by the trabecular and cortical bones after being processed chemically and sterilized by ethylene oxide. Samples of cancellous and cortical bones obtained from young female albinus rats (Wistar) were assigned to four groups according to the type of treatment: Group I- drying; Group II- drying and ethylene oxide sterilization; III- chemical treatment; IV- chemical treatment and ethylene oxide sterilization. Half of this material was analyzed under ordinary light microscope and the other half using scanning electron microscopy. In all the samples, regardless the group, there was good preservation of the general morphology. For samples submitted to the chemical processing there was better preservation of the cellular content, whereas there was amalgamation of the fibres when ethylene oxide was used. Treatment with ethylene oxide caused amalgamation of the fibers, possibly because of heating and the chemical treatment contributed to a better cellular preservation of the osseous structure.

  10. A novel composite material specifically developed for ultrasound bone phantoms: cortical, trabecular and skull.

    Science.gov (United States)

    Wydra, A; Maev, R Gr

    2013-11-21

    In the various stages of developing diagnostic and therapeutic equipment, the use of phantoms can play a very important role in improving the process, help in implementation, testing and calibrations. Phantoms are especially useful in developing new applications and training new doctors in medical schools. However, devices that use different physical factors, such as MRI, Ultrasound, CT Scan, etc will require the phantom to be made of different physical properties. In this paper we introduce the properties of recently designed new materials for developing phantoms for ultrasonic human body investigation, which in today's market make up more than 30% in the world of phantoms. We developed a novel composite material which allows fabrication of various kinds of ultrasound bone phantoms to mimic most of the acoustical properties of human bones. In contrast to the ex vivo tissues, the proposed material can maintain the physical and acoustical properties unchanged for long periods of time; moreover, these properties can be custom designed and created to suit specific needs. As a result, we introduce three examples of ultrasound phantoms that we manufactured in our laboratory: cortical, trabecular and skull bone phantoms. The paper also presents the results of a comparison study between the acoustical and physical properties of actual human bones (reported in the referenced literatures) and the phantoms manufactured by us.

  11. Propagation of ultrasonic guided waves in an acrylic plate as a cortical-bone-mimicking phantom

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kang Il [Kangwon National University, Chuncheon (Korea, Republic of); Choi, Bok Kyoung [Maritime Security Research Center, KIOST, Ansan (Korea, Republic of)

    2014-12-15

    The present study aims to investigate the propagation of ultrasonic guided waves in an acrylic plate as a cortical-bone-mimicking phantom. The velocities of the guided waves in a 5-mm-thick acrylic plate were measured by using the axial transmission technique. A pure A0 Lamb mode could be successfully launched in the 5-mm-thick acrylic plate through a time reversal process of Lamb waves, consistent with the fact that the time reversal process can automatically compensate for the dispersive nature of Lamb waves. The experimental velocities of the slow guided wave (SGW) and the time-reversed Lamb wave were found to be in reasonable agreement with the theoretical group velocity of the A0 Lamb mode, suggesting that both the SGW and the time-reversed Lamb wave excited in the 5-mm-thick acrylic plate correspond to the A0 Lamb mode. These results suggest that the time reversal process of Lamb waves can be usefully applied to noninvasive characterization of long cortical bones.

  12. Comparison of mechanical and ultrasound elastic modulus of ovine tibial cortical bone.

    Science.gov (United States)

    Grant, Caroline A; Wilson, Lance J; Langton, Christian; Epari, Devakar

    2014-07-01

    Finite element models of bones can be created by deriving geometry from an X-ray CT scan. Material properties such as the elastic modulus can then be applied using either a single or set of homogeneous values, or individual elements can have local values mapped onto them. Values for the elastic modulus can be derived from the CT density values using an elasticity versus density relationship. Many elasticity-density relationships have been reported in the literature for human bone. However, while ovine in vivo models are common in orthopaedic research, no work has been done to date on creating FE models of ovine bones. To create these models and apply relevant material properties, an ovine elasticity-density relationship needs to be determined. Using fresh frozen ovine tibias the apparent density of regions of interest was determined from a clinical CT scan. The bones were the sectioned into cuboid samples of cortical bone from the regions of interest. Ultrasound was used to determine the elastic modulus in each of three directions - longitudinally, radially and tangentially. Samples then underwent traditional compression testing in each direction. The relationships between apparent density and both ultrasound, and compression modulus in each direction were determined. Ultrasound testing was found to be a highly repeatable non-destructive method of calculating the elastic modulus, particularly suited to samples of this size. The elasticity-density relationships determined in the longitudinal direction were very similar between the compression and ultrasound data over the density range examined. A clear difference was seen in the elastic modulus between the longitudinal and transverse directions of the bone samples, and a transverse elasticity-density relationship is also reported.

  13. Individual-specific multi-scale finite element simulation of cortical bone of human proximal femur

    Energy Technology Data Exchange (ETDEWEB)

    Ascenzi, Maria-Grazia, E-mail: mgascenzi@mednet.ucla.edu [UCLA/Orthopaedic Hospital, Department of Orthopaedic Surgery, Rehabilitation Bldg, Room 22-69, 1000 Veteran Avenue, University of California, Los Angeles, CA 90095 (United States); Kawas, Neal P., E-mail: nealkawas@ucla.edu [UCLA/Orthopaedic Hospital, Department of Orthopaedic Surgery, Rehabilitation Bldg, Room 22-69, 1000 Veteran Avenue, University of California, Los Angeles, CA 90095 (United States); Lutz, Andre, E-mail: andre.lutz@hotmail.de [Institute of Biomechanics and Numerical Mechanics, Leibniz University Hannover, 30167 Hannover (Germany); Kardas, Dieter, E-mail: kardas@ibnm.uni-hannover.de [ContiTech Vibration Control, Jaedekamp 30 None, 30419 Hannover (Germany); Nackenhorst, Udo, E-mail: nackenhorst@ibnm.uni-hannover.de [Institute of Biomechanics and Numerical Mechanics, Leibniz University Hannover, 30167 Hannover (Germany); Keyak, Joyce H., E-mail: jhkeyak@uci.edu [Department of Radiological Sciences, Medical Sciences I, Bldg 811, Room B140, University of California, Irvine, CA 92697-5000 (United States)

    2013-07-01

    We present an innovative method to perform multi-scale finite element analyses of the cortical component of the femur using the individual’s (1) computed tomography scan; and (2) a bone specimen obtained in conjunction with orthopedic surgery. The method enables study of micro-structural characteristics regulating strains and stresses under physiological loading conditions. The analysis of the micro-structural scenarios that cause variation of strain and stress is the first step in understanding the elevated strains and stresses in bone tissue, which are indicative of higher likelihood of micro-crack formation in bone, implicated in consequent remodeling or macroscopic bone fracture. Evidence that micro-structure varies with clinical history and contributes in significant, but poorly understood, ways to bone function, motivates the method’s development, as does need for software tools to investigate relationships between macroscopic loading and micro-structure. Three applications – varying region of interest, bone mineral density, and orientation of collagen type I, illustrate the method. We show, in comparison between physiological loading and simple compression of a patient’s femur, that strains computed at the multi-scale model’s micro-level: (i) differ; and (ii) depend on local collagen-apatite orientation and degree of calcification. Our findings confirm the strain concentration role of osteocyte lacunae, important for mechano-transduction. We hypothesize occurrence of micro-crack formation, leading either to remodeling or macroscopic fracture, when the computed strains exceed the elastic range observed in micro-structural testing.

  14. Histopathological and Histomorphometrical Effects of Atorvastatin on Experimental Femoral Cortical Bone Defect Healing in Rats

    Directory of Open Access Journals (Sweden)

    M Valilu

    2012-05-01

    Full Text Available Background: Bone remodeling has always been the goal of surgeons for a long time. Recently, it was shown that statins that are commonly prescribed for lowering cholesterol also have beneficial effects on bone healing. Therefore, the present study was undertaken to evaluate the probable effects of atorvastatin on osteogenesis in the rat femur. Methods: This experimental study was conducted on 30 male Sprague-Dawley (SD rats. The animals were divided randomly into one control and two experiment groups. After induction of anesthesia, a hole of 2 mm in diameter was made in femur width. The control group received physiological serum but the experiment groups one and two, respectively, received 10 and 20 mg/kg/PO of atorvastatin on daily basis. After euthanizing the rats, histopathological and histomorphometrical evaluations of the bones were performed 45 days after the intervention. Results: In the control group, the defects seemed to be filled with woven bone and bone marrow, depictive of a poor osteogenic activity. In the experiment groups, many osteoblast groupings and young bone trabeculae had been formed and bone trabeculae were more organized. Histomorphometric results, showed that atorvastatin had significantly promoted bone healing in the experiment groups compared with the controls (P<0.001. Moreover, the analysis showed that atorvastatin had more significant effects in group three receiving high doses of the medication in comparison with group two (P<0.001. Conclusion: The findings of this study showed that atorvastatin is capable of stimulating osteogenesis in rats.

  15. [Olpadronate prevents cortical and trabecular bone loss induced by supraphysiological dosis of thyroxine in ovariectomized rats].

    Science.gov (United States)

    Zeni, S N; Gómez Acotto, C; Di Gregorio, S

    1998-01-01

    The aim of the present report was to clarify the effect of excess T4 on axial and peripheral bone mineral density (BMD) in estrogen-depleted rats. The protective effect of olpadronate (Olpa) on axial and peripheral bone mass in thyroxine-treated rats was also investigated. Female Sprague-Dawley rats were used: SHAM, OVX + Vh, OVX + Olpa (0.3 mg/kg/week), OVX + T4 (250 micrograms/kg/day) and OVX + T4 + Olpa rats. OVX + Vh group presented a BMD lower than SHAM in the tibia (p < 0.01) but not in femur or lumbar spine; the middle tibia BMD did not change but it was lower at the distal (pns.) and proximal levels (p < 0.003) in OVX + Vh. OVX + T4 rats presented a BMD significantly lower than OVX + Vh rats in total tibia (p < 0.02), femur (p < 0.006) and lumbar spine (p < 0.006). Moreover the BMD was lower in all studied areas of the tibia, but it was statistically significant only at the middle level (p < 0.004). OVX + Olpa rats had a BMD higher than OVX + Vh rats in femur (p < 0.002), lumbar spine (p < 0.0001), total (p < 0.001) and proximal tibia (p < 0.001). Surprisingly, total and proximal tibia BMD values in OVX + Olpa rats presented a BMD significantly higher than OVX + T4 rats in femur (p < 0.001), lumbar spine (p < 0.001), tibia (p < 0.001) and proximal tibia (p < 0.0001). It is important to point out that OVX + T4 + Olpa BMD was significantly higher than in SHAM rats at the lumbar spine, total and proximal tibia (p < 0.01). The present study suggests that although supraphysiological thyroid hormone affected both cortical and trabecular bone, under estrogen-depleted conditions, the cortical bone appears to be more sensitive than the trabecular bone to T4 treatment. We also found that Olpa could prevent the peripheral and axial bone loss induced by thyroid hormone excess.

  16. Synchrotron ultraviolet microspectroscopy on rat cortical bone: involvement of tyrosine and tryptophan in the osteocyte and its environment.

    Directory of Open Access Journals (Sweden)

    Stéphane Pallu

    Full Text Available Alcohol induced osteoporosis is characterized by a bone mass decrease and microarchitecture alterations. Having observed an excess in osteocyte apoptosis, we aimed to assess the bone tissue biochemistry, particularly in the osteocyte and its environment. For this purpose, we used a model of alcohol induced osteoporosis in rats. Bone sections of cortical bone were investigated using synchrotron UV-microspectrofluorescence at subcellular resolution. We show that bone present three fluorescence peaks at 305, 333 and 385 nm, respectively corresponding to tyrosine, tryptophan and collagen. We have determined that tyrosine/collagen and tryptophan/collagen ratios were higher in the strong alcohol consumption group. Tryptophan is related to the serotonin metabolism involved in bone formation, while tyrosine is involved in the activity of tyrosine kinases and phosphatases in osteocytes. Our experiment represents the first combined synchrotron UV microspectroscopy analysis of bone tissue with a quantitative biochemical characterization in the osteocyte and surrounding matrix performed separately.

  17. A weighted osteon morphotype score outperforms regional osteon percent prevalence calculations for interpreting cortical bone adaptation.

    Science.gov (United States)

    Skedros, John G; Kiser, Casey J; Mendenhall, Shaun D

    2011-01-01

    Using circularly polarized light microscopy,we described a weighted-scoring method for quantifying regional distributions of six secondary osteon morphotypes(Skedros et al.: Bone 44 (2009) 392-403). This osteon morphotype score (MTS) strongly correlated with "tension" and "compression" cortices produced by habitual bending. In the present study, we hypothesized that the osteon MTS is superior to a relatively simpler method based on the percent prevalence (PP) of these osteon morphotypes. This was tested in proximal femoral diaphyses of adult chimpanzees and habitually bent bones: calcanei from sheep, deer, and horses, radii from sheep and horses, and third metacarpals (MC3s) from horses. Sheep tibiae were examined because their comparatively greater torsion/shear would not require regional variations in osteon morphotypes. Predominant collagen fiber orientation (CFO), a predictor of regionally prevalent/predominant strain mode, was quantified as image gray levels (birefringence). Ten PP calculations were conducted. Although PP calculations were similar to the osteon MTS in corroborating CFO differences between "tension" and "compression" cortices of the chimpanzee femora and most of the habitually bent bones, PP calculations failed to show a compression/tension difference in equine MC3s and sheep radii. With the exception of the prevalence of the "distributed" osteon morphotype, correlations of PP calculations with CFO were weak and/or negative. By contrast, the osteon MTS consistently showed positive correlations with predominant CFO. Compared with the osteon MTS and predominant CFO, regional variations in PP of osteon morpho types are not stronger predictors of nonuniform strain distributions produced by bending.

  18. Reduced cortical bone compositional heterogeneity with bisphosphonate treatment in postmenopausal women with intertrochanteric and subtrochanteric fractures.

    Science.gov (United States)

    Donnelly, Eve; Meredith, Dennis S; Nguyen, Joseph T; Gladnick, Brian P; Rebolledo, Brian J; Shaffer, Andre D; Lorich, Dean G; Lane, Joseph M; Boskey, Adele L

    2012-03-01

    Reduction of bone turnover with bisphosphonate treatment alters bone mineral and matrix properties. Our objective was to investigate the effect of bisphosphonate treatment on bone tissue properties near fragility fracture sites in the proximal femur in postmenopausal women with osteoporosis. The mineral and collagen properties of corticocancellous biopsies from the proximal femur were compared in bisphosphonate-naive (-BIS, n = 20) and bisphosphonate-treated (+BIS, n = 20, duration 7 ± 5 years) patients with intertrochanteric (IT) and subtrochanteric (ST) fractures using Fourier transform infrared imaging (FTIRI). The mean values of the FTIRI parameter distributions were similar across groups, but the widths of the parameter distributions tended to be reduced in the +BIS group relative to the -BIS group. Specifically, the widths of the cortical collagen maturity and crystallinity were reduced in the +BIS group relative to those of the -BIS group by 28% (+BIS 0.45 ± 0.18 versus -BIS 0.63 ± 0.28, p = 0.03) and 17% (+BIS 0.087 ± 0.012 versus -BIS 0.104 ± 0.036, p = 0.05), respectively. When the tissue properties were examined as a function of fracture morphology within the +BIS group, the FTIR parameters were generally similar regardless of fracture morphology. However, the cortical mineral:matrix ratio was 8% greater in tissue from patients with atypical ST fractures (n = 6) than that of patients with typical (IT or spiral ST) fractures (n = 14) (Atypical 5.6 ± 0.3 versus Typical 5.2 ± 0.5, p = 0.03). Thus, although the mean values of the FTIR properties were similar in both groups, the tissue in bisphosphonate-treated patients had a more uniform composition than that of bisphosphonate-naive patients. The observed reductions in mineral and matrix heterogeneity may diminish tissue-level toughening mechanisms.

  19. Elastic moduli of untreated, demineralized and deproteinized cortical bone: validation of a theoretical model of bone as an interpenetrating composite material.

    Science.gov (United States)

    Hamed, E; Novitskaya, E; Li, J; Chen, P-Y; Jasiuk, I; McKittrick, J

    2012-03-01

    A theoretical experimentally based multi-scale model of the elastic response of cortical bone is presented. It portrays the hierarchical structure of bone as a composite with interpenetrating biopolymers (collagen and non-collagenous proteins) and minerals (hydroxyapatite), together with void spaces (porosity). The model involves a bottom-up approach and employs micromechanics and classical lamination theories of composite materials. Experiments on cortical bone samples from bovine femur include completely demineralized and deproteinized bones as well as untreated bone samples. Porosity and microstructure are characterized using optical and scanning electron microscopy, and micro-computed tomography. Compression testing is used to measure longitudinal and transverse elastic moduli of all three bone types. The characterization of structure and properties of these three bone states provides a deeper understanding of the contributions of the individual components of bone to its elastic response and allows fine tuning of modeling assumptions. Very good agreement is found between theoretical modeling and compression testing results, confirming the validity of the interpretation of bone as an interpenetrating composite material.

  20. Development of a Three-Dimensional (3D Printed Biodegradable Cage to Convert Morselized Corticocancellous Bone Chips into a Structured Cortical Bone Graft

    Directory of Open Access Journals (Sweden)

    Ying-Chao Chou

    2016-04-01

    Full Text Available This study aimed to develop a new biodegradable polymeric cage to convert corticocancellous bone chips into a structured strut graft for treating segmental bone defects. A total of 24 adult New Zealand white rabbits underwent a left femoral segmental bone defect creation. Twelve rabbits in group A underwent three-dimensional (3D printed cage insertion, corticocancellous chips implantation, and Kirschner-wire (K-wire fixation, while the other 12 rabbits in group B received bone chips implantation and K-wire fixation only. All rabbits received a one-week activity assessment and the initial image study at postoperative 1 week. The final image study was repeated at postoperative 12 or 24 weeks before the rabbit scarification procedure on schedule. After the animals were sacrificed, both femurs of all the rabbits were prepared for leg length ratios and 3-point bending tests. The rabbits in group A showed an increase of activities during the first week postoperatively and decreased anterior cortical disruptions in the postoperative image assessments. Additionally, higher leg length ratios and 3-point bending strengths demonstrated improved final bony ingrowths within the bone defects for rabbits in group A. In conclusion, through this bone graft converting technique, orthopedic surgeons can treat segmental bone defects by using bone chips but with imitate characters of structured cortical bone graft.

  1. Development of a Three-Dimensional (3D) Printed Biodegradable Cage to Convert Morselized Corticocancellous Bone Chips into a Structured Cortical Bone Graft.

    Science.gov (United States)

    Chou, Ying-Chao; Lee, Demei; Chang, Tzu-Min; Hsu, Yung-Heng; Yu, Yi-Hsun; Liu, Shih-Jung; Ueng, Steve Wen-Neng

    2016-04-20

    This study aimed to develop a new biodegradable polymeric cage to convert corticocancellous bone chips into a structured strut graft for treating segmental bone defects. A total of 24 adult New Zealand white rabbits underwent a left femoral segmental bone defect creation. Twelve rabbits in group A underwent three-dimensional (3D) printed cage insertion, corticocancellous chips implantation, and Kirschner-wire (K-wire) fixation, while the other 12 rabbits in group B received bone chips implantation and K-wire fixation only. All rabbits received a one-week activity assessment and the initial image study at postoperative 1 week. The final image study was repeated at postoperative 12 or 24 weeks before the rabbit scarification procedure on schedule. After the animals were sacrificed, both femurs of all the rabbits were prepared for leg length ratios and 3-point bending tests. The rabbits in group A showed an increase of activities during the first week postoperatively and decreased anterior cortical disruptions in the postoperative image assessments. Additionally, higher leg length ratios and 3-point bending strengths demonstrated improved final bony ingrowths within the bone defects for rabbits in group A. In conclusion, through this bone graft converting technique, orthopedic surgeons can treat segmental bone defects by using bone chips but with imitate characters of structured cortical bone graft.

  2. Tensile material properties of human rib cortical bone under quasi-static and dynamic failure loading and influence of the bone microstucture on failure characteristics

    CERN Document Server

    Subit, Damien; Valazquez-Ameijide, Juan; Arregui-Dalmases, Carlos; Crandall, Jeff

    2011-01-01

    Finite element models of the thorax are under development to assist vehicle safety researchers with the design of countermeasures such as advanced restrain systems. Computational models have become more refined with increasing geometrical complexity as element size decreases. These finite element models can now capture small geometrical features with an attempt to predict fracture. However, the bone material properties currently available, and in particular the rate sensitivity, have been mainly determined from compression tests or tests on long bones. There is a need for a new set of material properties for the human rib cortical bone. With this objective, a new clamping technique was developed to test small bone coupons under tensile loading. Ten coupons were harvested from the cortical shell of the sixth and seventh left ribs from three cadavers. The coupons were tested to fracture under quasi-static (target strain rate of 0.07 %/s) and dynamic loading (target strain rate of 170 %/s). Prior to testing, eac...

  3. Evaluation of outcomes of tympanoplasties with and without cortical mastoidectomy

    Directory of Open Access Journals (Sweden)

    Madayambath Sagesh

    2014-01-01

    Full Text Available Context: Even today well-trained and experienced otologists remain divided as to the importance of combining mastoidectomy with tympanoplasty in the treatment of chronic non-cholesteatomatous otitis media. We performed a comparison of patients with postinfectious simple tympanic membrane perforations treated with tympanoplasty or with tympanoplasty combined with intact canal wall mastoidectomy, in terms of outcome. Aims: The aim of the study was to evaluate the outcomes of tympanoplasties with and without cortical mastoidectomy in terms of graft uptake rate and hearing improvement. Settings and Design: A combination of retrospective and prospective cohort study. Materials and Methods: A total of 65 patients undergoing tympanoplasty with or without cortical mastoidectomy were included in the study and were followed up for a period of one year for the graft uptake and hearing improvement. Statistical analysis used: Fisher′s exact test and chi square test. Results: In our study, there was no significant difference in the graft uptake rate or the hearing improvement in both these groups. Conclusions: As per this study, it can be concluded that the addition of cortical mastoidectomy to type I tympanoplasty did not improve the graft uptake rate or the hearing improvement in cases of chronic suppurative otitis media tubotympanic disease.

  4. A 3D Multiscale Modelling of Cortical Bone Structure, Using the Inverse Identification Method: Microfibril Scale Study

    CERN Document Server

    Barkaoui, Abdelwahed

    2011-01-01

    Complexity and heterogeneity of bone tissue require a multiscale modelling to understand their mechanical behaviour and their remodelling mechanism. Human cortical bone structure consists of six structural scale levels which are the (macroscopic) cortical bone, osteonal, lamellar, fibrous, fibril and microfibril. In this paper, a 3D model based on finite elements method was achieved to study the nanomechanical behaviour of collagen Microfibril. The mechanical properties and the geometry (gap, overlap and diameter) of both tropocollagen and mineral were taken into consideration as well as the effects of cross-links. An inverse identification method has been applied to determine equivalent averaged properties in order to link up these nanoscopic characteristics to the macroscopic mechanical behaviour of bone tissue. Results of nanostructure modelling of the nanomechanical properties of strain deformation under varying cross-links were investigated in this work.

  5. Comparison of interradicular distances and cortical bone thickness in Thai patients with class I and class II skeletal patterns using cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Khumsarn, Nattida [Dental Division of Lamphun Hospital, Lamphun (Thailand); Patanaporn, Virush; Janhom, Apirum; Jotikasthira, Dhirawat [Faculty of Dentistry, Chiang Mai University, Chiang Mai (Thailand)

    2016-06-15

    This study evaluated and compared interradicular distances and cortical bone thickness in Thai patients with Class I and Class II skeletal patterns, using cone-beam computed tomography (CBCT). Pretreatment CBCT images of 24 Thai orthodontic patients with Class I and Class II skeletal patterns were included in the study. Three measurements were chosen for investigation: the mesiodistal distance between the roots, the width of the buccolingual alveolar process, and buccal cortical bone thickness. All distances were recorded at five different levels from the cementoenamel junction (CEJ). Descriptive statistical analysis and t-tests were performed, with the significance level for all tests set at p<0.05. Patients with a Class II skeletal pattern showed significantly greater maxillary mesiodistal distances (between the first and second premolars) and widths of the buccolingual alveolar process (between the first and second molars) than Class I skeletal pattern patients at 10 mm above the CEJ. The maxillary buccal cortical bone thicknesses between the second premolar and first molar at 8 mm above the CEJ in Class II patients were likewise significantly greater than in Class I patients. Patients with a Class I skeletal pattern showed significantly wider mandibular buccolingual alveolar processes than did Class II patients (between the first and second molars) at 4, 6, and 8 mm below the CEJ. In both the maxilla and mandible, the mesiodistal distances, the width of the buccolingual alveolar process, and buccal cortical bone thickness tended to increase from the CEJ to the apex in both Class I and Class II skeletal patterns.

  6. Comparison of interradicular distances and cortical bone thickness in Thai patients with Class I and Class II skeletal patterns using cone-beam computed tomography

    Science.gov (United States)

    Khumsarn, Nattida; Patanaporn, Virush; Jotikasthira, Dhirawat

    2016-01-01

    Purpose This study evaluated and compared interradicular distances and cortical bone thickness in Thai patients with Class I and Class II skeletal patterns, using cone-beam computed tomography (CBCT). Materials and Methods Pretreatment CBCT images of 24 Thai orthodontic patients with Class I and Class II skeletal patterns were included in the study. Three measurements were chosen for investigation: the mesiodistal distance between the roots, the width of the buccolingual alveolar process, and buccal cortical bone thickness. All distances were recorded at five different levels from the cementoenamel junction (CEJ). Descriptive statistical analysis and t-tests were performed, with the significance level for all tests set at p<0.05. Results Patients with a Class II skeletal pattern showed significantly greater maxillary mesiodistal distances (between the first and second premolars) and widths of the buccolingual alveolar process (between the first and second molars) than Class I skeletal pattern patients at 10 mm above the CEJ. The maxillary buccal cortical bone thicknesses between the second premolar and first molar at 8 mm above the CEJ in Class II patients were likewise significantly greater than in Class I patients. Patients with a Class I skeletal pattern showed significantly wider mandibular buccolingual alveolar processes than did Class II patients (between the first and second molars) at 4, 6, and 8 mm below the CEJ. Conclusion In both the maxilla and mandible, the mesiodistal distances, the width of the buccolingual alveolar process, and buccal cortical bone thickness tended to increase from the CEJ to the apex in both Class I and Class II skeletal patterns. PMID:27358819

  7. Biomedical titanium alloys with Young’s moduli close to that of cortical bone

    Science.gov (United States)

    Niinomi, Mitsuo; Liu, Yi; Nakai, Masaki; Liu, Huihong; Li, Hua

    2016-01-01

    Biomedical titanium alloys with Young’s moduli close to that of cortical bone, i.e., low Young’s modulus titanium alloys, are receiving extensive attentions because of their potential in preventing stress shielding, which usually leads to bone resorption and poor bone remodeling, when implants made of their alloys are used. They are generally β-type titanium alloys composed of non-toxic and allergy-free elements such as Ti–29Nb–13Ta–4.6Zr referred to as TNTZ, which is highly expected to be used as a biomaterial for implants replacing failed hard tissue. Furthermore, to satisfy the demands from both patients and surgeons, i.e., a low Young’s modulus of the whole implant and a high Young’s modulus of the deformed part of implant, titanium alloys with changeable Young’s modulus, which are also β-type titanium alloys, for instance Ti–12Cr, have been developed. In this review article, by focusing on TNTZ and Ti–12Cr, the biological and mechanical properties of the titanium alloys with low Young’s modulus and changeable Young’s modulus are described. In addition, the titanium alloys with shape memory and superelastic properties were briefly addressed. Surface modifications for tailoring the biological and anti-wear/corrosion performances of the alloys have also been briefly introduced. PMID:27252887

  8. Biomedical titanium alloys with Young's moduli close to that of cortical bone.

    Science.gov (United States)

    Niinomi, Mitsuo; Liu, Yi; Nakai, Masaki; Liu, Huihong; Li, Hua

    2016-09-01

    Biomedical titanium alloys with Young's moduli close to that of cortical bone, i.e., low Young's modulus titanium alloys, are receiving extensive attentions because of their potential in preventing stress shielding, which usually leads to bone resorption and poor bone remodeling, when implants made of their alloys are used. They are generally β-type titanium alloys composed of non-toxic and allergy-free elements such as Ti-29Nb-13Ta-4.6Zr referred to as TNTZ, which is highly expected to be used as a biomaterial for implants replacing failed hard tissue. Furthermore, to satisfy the demands from both patients and surgeons, i.e., a low Young's modulus of the whole implant and a high Young's modulus of the deformed part of implant, titanium alloys with changeable Young's modulus, which are also β-type titanium alloys, for instance Ti-12Cr, have been developed. In this review article, by focusing on TNTZ and Ti-12Cr, the biological and mechanical properties of the titanium alloys with low Young's modulus and changeable Young's modulus are described. In addition, the titanium alloys with shape memory and superelastic properties were briefly addressed. Surface modifications for tailoring the biological and anti-wear/corrosion performances of the alloys have also been briefly introduced.

  9. Comparison of cortical bone measurements between pQCT and HR-pQCT.

    Science.gov (United States)

    Lala, Deena; Cheung, Angela M; Gordon, Chris; Giangregorio, Lora

    2012-01-01

    The primary purpose of this study was to determine the accuracy of tibial cortical thickness measurements derived from peripheral quantitative computed tomography (pQCT) with analysis based on the circular ring model, using high-resolution peripheral quantitative computed tomography (HR-pQCT) (isotopic voxel size of 82 μm) as a gold standard. The secondary objective was to evaluate whether the accuracy of the pQCT-based estimates of cortical thickness (CTh), cortical area (CoA), cortical density (CDen), and total area (TotA) improve with alterations of voxel size from the standard 0.5-0.2mm. Fifteen dry tibia specimens were immersed in saline in a sealed cylinder and scanned 22.5mm from the distal tibia plateau using pQCT and HR-pQCT. pQCT yielded higher values for CTh and CDen and lower values for CoA. The differences between imaging techniques increased as the average CTh increased. No systematic bias was observed for CDen, CoA, and TotA. Similar differences were found between pQCT with voxel size 0.2mm and HR-pQCT. Significant correlations were observed for CTh (R=0.97, p ≤ 0.0001), CDen (R=0.99, p ≤ 0.0001), CoA (R=0.98, p ≤ 0.0001), and TotA (R=1.0, p ≤ 0.0001) when pQCT- and HR-pQCT-derived values were compared irrespective of which voxel size was used. Measurement variability between the imaging techniques was evident. Future studies aimed at examining cortical structure with pQCT should note that there are differences between the 2 techniques. Copyright © 2012 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

  10. An Increase in Forearm Cortical Bone Size After Menopause May Influence the Estimated Bone Mineral Loss--A 28-Year Prospective Observational Study.

    Science.gov (United States)

    Karlsson, Magnus K; Ahlborg, Henrik G; Svejme, Ola; Nilsson, Jan-Åke; Rosengren, Björn E

    2016-01-01

    Areal bone mineral density (aBMD) is the most common estimate of bone mass, incorporated in the World Health Organization definition of osteoporosis. However, aBMD depends on not only the amount of mineral but also the bone size. The estimated postmenopausal decline in aBMD could because of this be influenced by changes in bone size.We measured bone mineral content (BMC; mg), aBMD (mg/cm2), and bone width (mm) by single-photon absorptiometry at the cortical site of the forearm in a population-based sample of 105 Caucasian women. We conducted 12 measurements during a 28-yr period from mean 5 yr (range: 2-9) before menopause to mean 24 yr (range: 18-28) after menopause. We calculated individual slopes for changes in the periods before menopause, 0-transient increase in forearm bone size that will influence the by aBMD estimated cortical loss in bone minerals. Published by Elsevier Inc.

  11. Microstructure and compressive mechanical properties of cortical bone in children with osteogenesis imperfecta treated with bisphosphonates compared with healthy children.

    Science.gov (United States)

    Imbert, Laurianne; Aurégan, Jean-Charles; Pernelle, Kélig; Hoc, Thierry

    2015-06-01

    Osteogenesis imperfecta (OI) is a genetic disorder characterized by a change in bone tissue quality, but little data are available to describe the factors involved at the macroscopic scale. To better understand the effect of microstructure alterations on the mechanical properties at the sample scale, we studied the structural and mechanical properties of six cortical bone samples from children with OI treated with bisphosphonates and compared them to the properties of three controls. Scanning electron microscopy, high resolution computed tomography and compression testing were used to assess these properties. More resorption cavities and a higher osteocyte lacunar density were observed in OI bone compared with controls. Moreover, a higher porosity was measured for OI bones along with lower macroscopic Young's modulus, yield stress and ultimate stress. The microstructure was impaired in OI bones; the higher porosity and osteocyte lacunar density negatively impacted the mechanical properties and made the bone more prone to fracture.

  12. Harvesting bone graft from the olecranon: a quantitative and biomechanical comparison of proximal and dorsal cortical windows.

    Science.gov (United States)

    Anderson, Matthew C; Chong, Alexander C M; Lucas, George L; Czuwala, Peter J; Wooley, Paul H

    2014-07-01

    We conducted a study to compare 2 techniques of harvesting ulna bone graft from the olecranon, one using a proximal cortical window (PCW), the other using a dorsal cortical window (DCW), in terms of cancellous bone graft quantity and ulna fracture strength after graft harvest. Cancellous bone was harvested from 8 pairs of embalmed cadaver proximal ulna. Each side of a matched pair was randomly assigned to graft harvest using either a PCW or a DCW approach. Packed bone volume (PBV) was determined by placing the harvested bone into a 3-mL syringe and compacting it with a quasi-static 25-N load. Biomechanical cantilever bending was performed on each elbow to determine load at failure (LF). Paired Student t tests were used to compare PBV and LF between the experimental and control groups. The graft PBV obtained from the matched-pair specimens was not statistically different between the PCW and DCW approaches. Ulnas subjected to proximal bone harvest exhibited higher LF than ulnas subjected to dorsal bone harvest, though the difference was not statistically significant. Compared with bone graft harvest using the traditional DCW approach, harvest using a PCW approach provides similar cancellous graft amounts and exhibits similar fracture resistance.

  13. Reference point indentation study of age-related changes in porcine femoral cortical bone.

    Science.gov (United States)

    Rasoulian, Ramin; Raeisi Najafi, Ahmad; Chittenden, Michael; Jasiuk, Iwona

    2013-06-21

    The reference point indentation (RPI) method is a microindentation technique involving successive indentation cycles. We employed RPI to measure average stiffness (Ave US), indentation distance increase (IDI), total indentation distance (TID), average energy dissipated (Ave ED), and creep indentation distance (CID) of swine femoral cortical bone (mid-diaphysis) as a function of age (1, 3.5, 6, 14.5, 24, and 48 months) and loading directions (longitudinal and transverse). The Ave US increases with animal age, while the IDI, TID, Ave ED, and CID decrease with age, for both longitudinal (transverse surface) and transverse (periosteal surface) loading directions. Longitudinal measurements generally give higher Ave US and lower IDI and TID values compared to transverse measurements. The RPI measurements show similar trends to those obtained using nanoindentation test, and ash and water content tests.

  14. The reliability of cone-beam computed tomography to analyze trabecular and cortical bone structures: an in-vitro study

    OpenAIRE

    Huang, Yan; Dessel, Jeroen Van; Nicolielo, Laura; Van de Casteele, Elke; Slagmolen, Pieter; Jacobs, Reinhilde

    2015-01-01

    Huang Y., Van Dessel J., Nicolielo L., Van de Casteele E., Slagmolen P., Jacobs R., ''The reliability of cone-beam computed tomography to analyze trabecular and cortical bone structures: an in-vitro study'', 24th annual congress of the European Association for Osseointegration - EAO 2015, September 24-26, 2015, Stockholm, Sweden.

  15. Mechanical tests on the reconstructed anterior cruciate ligament fixed with allogenetic cortical bone cross-pin on the femoral side

    Institute of Scientific and Technical Information of China (English)

    Liu Chang; Liu Yujie; Zhang Yingze; Qu Feng; Li Shuyuan; Wang Junliang; Qi Wei

    2014-01-01

    Background Anterior cruciate ligament reconstruction (ACLR) has developed dramatically in the last century.Now,ACLR has become a reliable and productive procedure.Patients feel satisfied in >90% cases.The aim of this study was to evaluate the feasibility of allogenetic cortical bone cross-pin (ACBCP) used as a clinical fixation method in anterior cruciate ligament reconstruction on the femoral side based on biomechanical tests in vitro.Methods The specimens were provided by the bone banks of the First Affiliated Hospital of People's Liberation Army of General Hospital from September 2011 to June 2012.Fresh deep frozen human allogenetic cortical bone was machined into cross-pins which is 4.0 mm in diameter and 75.0 mm in length.Biomechanical parameters compared with Rigidfix were collected while cross-pins were tested in double-shear test.The load-to-failure test and cycling test were carried out in a goat model to reconstruct anterior cruciate ligament with Achilles tendon autograft on the femoral side fixed by human 4.0 mm ACBCP and 3.3 mm Rigidfix served as control.Maximum failure load,yield load,and stiffness of fixation in single load-to-failure test were compared between the two groups.Cycle-specific stiffness and displacement at cycles 1,30,200,400,and 1 000 were also compared in between.Results In double-shear test both maximum failed load and yield load of 4.0 mm humanACBCP were (1 236.998±201.940) N.Maximum failed load and yield load of Rigidfix were (807.929±110.511) N and (592.483±58.821) N.The differences of maximum failed load and yield load were significant between ACBCP and Rigidfix,P <0.05.The shear strength of ACBCP and Rigidfix were (49.243±8.039) MPa and (34.637±3.439) MPa,respectively,P <0.05.In the load-to-failure test ex vivo,yield load and maximum failed load of ACBCP fixation complexity ((867.104±132.856)N,(1 032.243±196.281) N) were higher than those of Rigidfix ((640.935±42.836) N,(800.568±64.890) N,P <0.05).However

  16. Multiscale approach including microfibril scale to assess elastic constants of cortical bone based on neural network computation and homogenization method

    CERN Document Server

    Barkaoui, Abdelwahed; Tarek, Merzouki; Hambli, Ridha; Ali, Mkaddem

    2014-01-01

    The complexity and heterogeneity of bone tissue require a multiscale modelling to understand its mechanical behaviour and its remodelling mechanisms. In this paper, a novel multiscale hierarchical approach including microfibril scale based on hybrid neural network computation and homogenisation equations was developed to link nanoscopic and macroscopic scales to estimate the elastic properties of human cortical bone. The multiscale model is divided into three main phases: (i) in step 0, the elastic constants of collagen-water and mineral-water composites are calculated by averaging the upper and lower Hill bounds; (ii) in step 1, the elastic properties of the collagen microfibril are computed using a trained neural network simulation. Finite element (FE) calculation is performed at nanoscopic levels to provide a database to train an in-house neural network program; (iii) in steps 2 to 10 from fibril to continuum cortical bone tissue, homogenisation equations are used to perform the computation at the higher s...

  17. Functional adaptation to mechanical loading in both cortical and cancellous bone is controlled locally and is confined to the loaded bones.

    Science.gov (United States)

    Sugiyama, Toshihiro; Price, Joanna S; Lanyon, Lance E

    2010-02-01

    In order to validate whether bones' functional adaptation to mechanical loading is a local phenomenon, we randomly assigned 21 female C57BL/6 mice at 19 weeks of age to one of three equal numbered groups. All groups were treated with isoflurane anesthesia three times a week for 2 weeks (approximately 7 min/day). During each anaesthetic period, the right tibiae/fibulae in the DYNAMIC+STATIC group were subjected to a peak dynamic load of 11.5 N (40 cycles with 10-s intervals between cycles) superimposed upon a static "pre-load" of 2.0 N. This total load of 13.5 N engendered peak longitudinal strains of approximately 1400 microstrain on the medial surface of the tibia at a middle/proximal site. The right tibiae/fibulae in the STATIC group received the static "pre-load" alone while the NOLOAD group received no artificial loading. After 2 weeks, the animals were sacrificed and both tibiae, fibulae, femora, ulnae and radii analyzed by three-dimensional high-resolution (5 mum) micro-computed tomography (microCT). In the DYNAMIC+STATIC group, the proximal trabecular percent bone volume and cortical bone volume at the proximal and middle levels of the right tibiae as well as the cortical bone volume at the middle level of the right fibulae were markedly greater than the left. In contrast, the left bones in the DYNAMIC+STATIC group showed no differences compared to the left or right bones in the NOLOAD or STATIC group. These microCT data were confirmed by two-dimensional examination of fluorochrome labels in bone sections which showed the predominantly woven nature of the new bone formed in the loaded bones. We conclude that the adaptive response in both cortical and trabecular regions of bones subjected to short periods of dynamic loading, even when this response is sufficiently vigorous to stimulate woven bone formation, is confined to the loaded bones and does not involve changes in other bones that are adjacent, contra-lateral or remote to them.

  18. Genetic algorithms as a useful tool for trabecular and cortical bone segmentation.

    Science.gov (United States)

    Janc, K; Tarasiuk, J; Bonnet, A S; Lipinski, P

    2013-07-01

    The aim of this study was to find a semi-automatic method of bone segmentation on the basis of computed tomography (CT) scan series in order to recreate corresponding 3D objects. So, it was crucial for the segmentation to be smooth between adjacent scans. The concept of graphics pipeline computing was used, i.e. simple graphics filters such as threshold or gradient were processed in a manner that the output of one filter became the input of the second one resulting in so called pipeline. The input of the entire stream was the CT scan and the output corresponded to the binary mask showing where a given tissue is located in the input image. In this approach the main task consists in finding the suitable sequence, types and parameters of graphics filters building the pipeline. Because of the high number of desired parameters (in our case 96), it was decided to use a slightly modified genetic algorithm. To determine fitness value, the mask obtained from the parameters found through genetic algorithms (GA) was compared with those manually prepared. The numerical value corresponding to such a comparison has been defined by Dice's coefficient. Preparation of reference masks for a few scans among the several hundreds of them was the only action done manually by a human expert. Using this method, very good results both for trabecular and cortical bones were obtained. It has to be emphasized that as no real border exists between these two bone types, the manually prepared reference masks were quite conventional and therefore charged with errors. As GA is a non-deterministic method, the present work also contains a statistical analysis of the relations existing between various GA parameters and fitness function. Finally the best sets of the GA parameters are proposed.

  19. Liver-derived IGF-I regulates cortical bone mass but is dispensable for the osteogenic response to mechanical loading in female mice.

    Science.gov (United States)

    Svensson, Johan; Windahl, Sara H; Saxon, Leanne; Sjögren, Klara; Koskela, Antti; Tuukkanen, Juha; Ohlsson, Claes

    2016-07-01

    Low circulating IGF-I is associated with increased fracture risk. Conditional depletion of IGF-I produced in osteoblasts or osteocytes inhibits the bone anabolic effect of mechanical loading. Here, we determined the role of endocrine IGF-I for the osteogenic response to mechanical loading in young adult and old female mice with adult, liver-specific IGF-I inactivation (LI-IGF-I(-/-) mice, serum IGF-I reduced by ≈70%) and control mice. The right tibia was subjected to short periods of axial cyclic compressive loading three times/wk for 2 wk, and measurements were performed using microcomputed tomography and mechanical testing by three-point bending. In the nonloaded left tibia, the LI-IGF-I(-/-) mice had lower cortical bone area and increased cortical porosity, resulting in reduced bone mechanical strength compared with the controls. Mechanical loading induced a similar response in LI-IGF-I(-/-) and control mice in terms of cortical bone area and trabecular bone volume fraction. In fact, mechanical loading produced a more marked increase in cortical bone mechanical strength, which was associated with a less marked increase in cortical porosity, in the LI-IGF-I(-/-) mice compared with the control mice. In conclusion, liver-derived IGF-I regulates cortical bone mass, cortical porosity, and mechanical strength under normal (nonloaded) conditions. However, despite an ∼70% reduction in circulating IGF-I, the osteogenic response to mechanical loading was not attenuated in the LI-IGF-I(-/-) mice.

  20. Mechanical and material properties of cortical and trabecular bone from cannabinoid receptor-1-null (Cnr1(-/-)) mice.

    Science.gov (United States)

    Khalid, Aysha B; Goodyear, Simon R; Ross, Ruth A; Aspden, Richard M

    2016-10-01

    The endocannabinoid system is known for its regulatory effects on bone metabolism through the cannabinoid receptors, Cnr1 and Cnr2. In this study we analysed the mechanical and material properties of long bones from Cnr1(-/-) mice on a C57BL/6 background. Tibiae and femora from 5- and 12-week-old mice were subjected to three-point bending to measure bending stiffness and yield strength. Elastic modulus, density and mineral content were measured in the diaphysis. Second moment of area (MOA2), inner and outer perimeters of the cortical shaft and trabecular fractional bone volume (BV/TV) were measured using micro-CT. In Cnr1(-/-) males and females at both ages the bending stiffness was reduced due to a smaller MOA2. Bone from Cnr1(-/-) females had a greater modulus than wild-type controls, although no differences were observed in males. BV/TV of 12-week-old Cnr1(-/-) females was greater than controls, although no difference was seen at 5-weeks. On the contrary, Cnr1(-/-) males had the same BV/TV as controls at 12-weeks while they had significantly lower values at 5-weeks. This study shows that deleting Cnr1 decreases the amount of cortical bone in both males and females at 12-weeks, but increases the amount of trabecular bone only in females.

  1. Histomorphometric Assessment of Cancellous and Cortical Bone Material Distribution in the Proximal Humerus of Normal and Osteoporotic Individuals: Significantly Reduced Bone Stock in the Metaphyseal and Subcapital Regions of Osteoporotic Individuals.

    Science.gov (United States)

    Sprecher, Christoph M; Schmidutz, Florian; Helfen, Tobias; Richards, R Geoff; Blauth, Michael; Milz, Stefan

    2015-12-01

    Osteoporosis is a systemic disorder predominantly affecting postmenopausal women but also men at an advanced age. Both genders may suffer from low-energy fractures of, for example, the proximal humerus when reduction of the bone stock or/and quality has occurred.The aim of the current study was to compare the amount of bone in typical fracture zones of the proximal humerus in osteoporotic and non-osteoporotic individuals.The amount of bone in the proximal humerus was determined histomorphometrically in frontal plane sections. The donor bones were allocated to normal and osteoporotic groups using the T-score from distal radius DXA measurements of the same extremities. The T-score evaluation was done according to WHO criteria. Regional thickness of the subchondral plate and the metaphyseal cortical bone were measured using interactive image analysis.At all measured locations the amount of cancellous bone was significantly lower in individuals from the osteoporotic group compared to the non-osteoporotic one. The osteoporotic group showed more significant differences between regions of the same bone than the non-osteoporotic group. In both groups the subchondral cancellous bone and the subchondral plate were least affected by bone loss. In contrast, the medial metaphyseal region in the osteoporotic group exhibited higher bone loss in comparison to the lateral side.This observation may explain prevailing fracture patterns, which frequently involve compression fractures and certainly has an influence on the stability of implants placed in this medial region. It should be considered when planning the anchoring of osteosynthesis materials in osteoporotic patients with fractures of the proximal humerus.

  2. Quantification of alterations in cortical bone geometry using Site Specificity Software in mouse models of aging and the responses to ovariectomy and altered loading

    Directory of Open Access Journals (Sweden)

    Gabriel L Galea

    2015-04-01

    Full Text Available Investigations into the effect of (remodelling stimuli on cortical bone in rodents normally rely on analysis of changes in bone mass and architecture at a narrow cross-sectional site. However, it is well established that the effects of axial loading produce site-specific changes throughout bones’ structure. Non-mechanical influences (e.g. hormones can be additional to or oppose locally-controlled adaptive responses and may have more generalized effects. Tools currently available to study site-specific cortical bone adaptation are limited. Here we applied novel Site-Specificity software to measure bone mass and architecture at each 1% site along the length of the mouse tibia from standard micro-computed tomography (μCT images. Resulting measures are directly comparable to those obtained through μCT analysis (R2 > 0.96. Site-Specificity Analysis was used to compare a number of parameters in tibiae from young adult (19-week-old versus aged (19-month-old mice; ovariectomized and entire mice; limbs subjected to short periods of axial loading or disuse induced by sciatic neurectomy. Age was associated with uniformly reduced cortical thickness and site-specific decreases in cortical area most apparent in the proximal tibia. Mechanical loading site-specifically increased cortical area and thickness in the proximal tibia. Disuse uniformly decreased cortical thickness and decreased cortical area in the proximal tibia. Ovariectomy uniformly reduced cortical area without altering cortical thickness. Differences in polar moment of inertia between experimental groups were only observed in the proximal tibia. Ageing and ovariectomy also altered eccentricity in the distal tibia. In summary, Site-Specificity Analysis provides a valuable tool for measuring changes in cortical bone mass and architecture along the entire length of a bone. Changes in the (remodelling response determined at a single site may not reflect the response at different locations within

  3. Development of a strain rate dependent material model of human cortical bone for computer-aided reconstruction of injury mechanisms.

    Science.gov (United States)

    Asgharpour, Zahra; Zioupos, Peter; Graw, Matthias; Peldschus, Steffen

    2014-03-01

    Computer-aided methods such as finite-element simulation offer a great potential in the forensic reconstruction of injury mechanisms. Numerous studies have been performed on understanding and analysing the mechanical properties of bone and the mechanism of its fracture. Determination of the mechanical properties of bones is made on the same basis used for other structural materials. The mechanical behaviour of bones is affected by the mechanical properties of the bone material, the geometry, the loading direction and mode and of course the loading rate. Strain rate dependency of mechanical properties of cortical bone has been well demonstrated in literature studies, but as many of these were performed on animal bones and at non-physiological strain rates it is questionable how these will apply in the human situations. High strain-rates dominate in a lot of forensic applications in automotive crashes and assault scenarios. There is an overwhelming need to a model which can describe the complex behaviour of bone at lower strain rates as well as higher ones. Some attempts have been made to model the viscoelastic and viscoplastic properties of the bone at high strain rates using constitutive mathematical models with little demonstrated success. The main objective of the present study is to model the rate dependent behaviour of the bones based on experimental data. An isotropic material model of human cortical bone with strain rate dependency effects is implemented using the LS-DYNA material library. We employed a human finite element model called THUMS (Total Human Model for Safety), developed by Toyota R&D Labs and the Wayne State University, USA. The finite element model of the human femur is extracted from the THUMS model. Different methods have been employed to develop a strain rate dependent material model for the femur bone. Results of one the recent experimental studies on human femur have been employed to obtain the numerical model for cortical femur. A

  4. Trabecular and Cortical Bone of Growing C3H Mice Is Highly Responsive to the Removal of Weightbearing.

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    Bing Li

    Full Text Available Genetic make-up strongly influences the skeleton's susceptibility to the loss of weight bearing with some inbred mouse strains experiencing great amounts of bone loss while others lose bone at much smaller rates. At young adulthood, female inbred C3H/HeJ (C3H mice are largely resistant to catabolic pressure induced by unloading. Here, we tested whether the depressed responsivity to unloading is inherent to the C3H genetic make-up or whether a younger age facilitates a robust skeletal response to unloading. Nine-week-old, skeletally immature, female C3H mice were subjected to 3wk of hindlimb unloading (HLU, n = 12 or served as normal baseline controls (BC, n = 10 or age-matched controls (AC, n = 12. In all mice, cortical and trabecular architecture of the femur, as well as levels of bone formation and resorption, were assessed with μCT, histomorphometry, and histology. Changes in bone marrow progenitor cell populations were determined with flow cytometry. Following 21d of unloading, HLU mice had 52% less trabecular bone in the distal femur than normal age-matched controls. Reflecting a loss of trabecular tissue compared to baseline controls, trabecular bone formation rates (BFR/BS in HLU mice were 40% lower than in age-matched controls. Surfaces undergoing osteoclastic resorption were not significantly different between groups. In the mid-diaphysis, HLU inhibited cortical bone growth leading to 14% less bone area compared to age-matched controls. Compared to AC, BFR/BS of HLU mice were 53% lower at the endo-cortical surface and 49% lower at the periosteal surface of the mid-diaphysis. The enriched osteoprogenitor cell population (OPC comprised 2% of the bone marrow stem cells in HLU mice, significantly different from 3% OPC in the AC group. These data show that bone tissue in actively growing C3H mice is lost rapidly, or fails to grow, during the removal of functional weight bearing-in contrast to the insignificant response previously

  5. Cortical bone resorption rate in elderly persons: Estimates from long-term in vivo measurements of 90Sr in the skeleton

    Energy Technology Data Exchange (ETDEWEB)

    Shagina, N. B.; Tolstykh, E. I.; Degteva, M. O.; Anspaugh, L. R.; Napier, Bruce A.

    2012-06-01

    The rate of cortical bone resorption was assessed from long-term in vivo measurements of 90Sr content in the skeleton for men aged 50-80 years and for women 0-30 years after menopause. Measurements of 90Sr were conducted with a whole body counter for residents of the Techa Riverside communities (Southern Urals, Russia), who ingested large amounts of 90Sr as a result of releases of liquid radioactive wastes into the river from the Mayak plutonium facility in early 1950s. The results of this study showed an increase in the rate of cortical bone resorption in both men and women, as based on the use of accidentally ingested 90Sr as a tracer for bone metabolism. In men there was a continuous gradual increase in the rate of cortical bone resorption after 55 years from 2.8 to 4.5%/year by the age of 75 years. In women, there was a doubled increase in the rate of cortical bone resorption after menopause of up to 6%/year; then the rate remained unchanged for 10-12 years with a subsequent gradual decline down to 5-5.5%/year. Comparison of the rate of cortical bone resorption in men and women older than 55 years showed that women expressed significantly higher levels of cortical bone resorption.

  6. Experimental investigations and finite element simulation of cutting heat in vibrational and conventional drilling of cortical bone.

    Science.gov (United States)

    Wang, Yu; Cao, Meng; Zhao, Xiangrui; Zhu, Gang; McClean, Colin; Zhao, Yuanyuan; Fan, Yubo

    2014-11-01

    Heat generated during bone drilling could cause irreversible thermal damage, which can lead to bone necrosis or even osteomyelitis. In this study, vibrational drilling was applied to fresh bovine bones to investigate the cutting heat in comparison with conventional drilling through experimental investigation and finite element analysis (FEA). The influence of vibrational frequency and amplitude on cutting heat generation and conduction were studied. The experimental results showed that, compared with the conventional drilling, vibrational drilling could significantly reduce the cutting temperature in drilling of cortical bone (P<0.05): the cutting temperature tended to decrease with increasing vibrational frequency and amplitude. The FEA results also showed that the vibrational amplitude holds a significant effect on the cutting heat conduction.

  7. Variation of the mineral density in cortical bone may serve to keep strain amplitudes within a physiological range.

    Science.gov (United States)

    de Jong, W C; van Ruijven, L J; Brugman, P; Langenbach, G E J

    2013-08-01

    Within-bone variation in mineral density could be functional. A heterogeneous mineral-density distribution might serve to maintain habitual amplitudes of bone strain within a non-harmful, i.e., physiological range. Regions of a bone that would be strained the most on the basis of architecture alone might have a higher mineral density to make them more stiff and resistant to strain. We hypothesised that the cortical bone of the rabbit mandible contains such a functional distribution of mineral density. We thereby expected similar mineral-density patterns in the mandibles of different individuals due to the shared masticatory function. Secondly, we hypothesised that the highest mineral densities occur in mandibular regions predicted to be exposed to the largest amplitudes of strain-when taking into account bone architecture only. Mineral-density maps of the cortical bone of rabbit mandibles were obtained using micro-computed tomography (μCT). The μCT scans of two rabbits were converted into finite-element models (FEMs). To predict mandibular deformation during biting, these models were loaded by muscle forces and reaction forces. The forces acted on the condyles and on either the incisal or molar bite point. The FEMs were assigned a homogeneous material stiffness to calculate the strain amplitudes that would occur when only the architecture of the mandibular bone would be of influence. We found the cortical bone-mineral density patterns to be similar in all six mandibles. The mineral density of the corpus was higher than that of the ramus. A second consistent feature of the mandibular mineral-density distribution was that the medial ridge of the temporal-muscle insertion groove contained more mineral than its surrounding regions. The strain amplitudes calculated with the FEMs were variable and did not feature clear corpo-ramal differences. However, specific mandibular bone sites calculated to be exposed to the largest amplitudes of strain, including the medial

  8. CT evaluation of primary epiphyseal bone abscesses

    Energy Technology Data Exchange (ETDEWEB)

    Azouz, E.M. (Dept. of Radiology, McGill Univ., Montreal Children' s Hospital, PQ (Canada)); Greenspan, A. (Dept. of Radiology, California Univ., Davis School of Medicine, Sacramento, CA (United States)); Marton, D. (Dept. of Radiology, Montreal Univ., Hopital Ste Justine, PQ (Canada))

    1993-01-01

    We reviewed the clinical, radiographic, and computed tomographic (CT) findings in eight children with a histologically proven diagnosis of epiphyseal or apophyseal osteomyelitis. In all cases the femur was involved: in five the osteomyelitis was localized in the femoral condyle, in two it was in the greater trochanter, and in one it was in the femoral head epiphysis. In four of the six cases of epiphyseal involvement there was associated joint effusion or septic arthritis. CT examination may demonstrate a serpentine tract, a sequestrum, cortical destruction or adjacent soft tissue swelling and can differentiate osteomyelitis from other epiphyseal lucent lesions, particularly chondroblastoma and osteoid osteoma. Early diagnosis helps avoid delays in initiating antibiotic or surgical treatment caused by the unusual (epiphyseal or apophyseal) location of the bone abscess. (orig./GD)

  9. USO DO ENXERTO ÓSSEO CORTICAL BOVINO CONSERVADO EM GLICERINA A 98% NA OSTEOTOMIA FEMORAL EM GATOS USE BOVINE CORTICAL BONE, PRESERVED IN 98% GLICERIN IN FEMORAL OSTEOTOMY IN CATS.

    Directory of Open Access Journals (Sweden)

    Lucia Helena de Carvalho Penha

    2008-12-01

    . The objective of this study was to evaluate clinically and radiographically the efficacy of xenografts as a substitute for methalic implants. Animals were divided into two groups: five young cats and five adult cats. Clinically, the weight-bearing on the operated limb was observed the day after surgery in all animals, with complete remission of lameness at 15 days and bone union in 16.6 weeks. In five young animals, in two of them, the grafts were fractured carrying a serious bone bending without fracture of feline femur. In the last two young cats, remodeling was noted in mean time of 75 days or 10.7 weeks. In five adult cats, all of them suffered overriding of the fragments of osteotomized bone with various degrees, where two cases were considered severe cases dut to fracture of feline femur without bone bending. In the three remaining animals with slightly overriding, one was a case of delayed union, one suffered tow surgical procedures due to graft fracture and one did not show a radiographic exuberant bone callus, with remodeling at 110 days. The use of the bonive xenograft preserved in 98% glycerol in young and adult cats used as intramedularry nails was perfectly employed, offering mechanical support in time of bone consolidation in all of 10 animals.

    KEY WORDS: Cortical bovine graft, cats, femur, fracture, osteotomy.

  10. Preliminary determination of calcium, phosphorus, and the calcium/phosphorus ratio in cortical bone of Chinstrap penguin using synchrotron X-ray fluorescence analysis

    Institute of Scientific and Technical Information of China (English)

    Xie Zhouqing; Cheng Bangbo; Sun Liguang; Huang Yuying; He Wei; Zhao Sanping

    2006-01-01

    Synchrotron radiation X-ray fluorescence (SR-XRF) approach was applied to analyzing of Chinstrap penguin (Pygoscelis Antarctica) cortical bone. The method enabled the in situ determination of Ca and P concentrations and the Ca/P ratio in cortical bone. The preliminary results show that: (1) there is the bone site-related difference for Ca and P concentrations. The mean values for the investigated parameters ( on a dry-weight basis) are: 30.7% (Ca) and 14.9% (P) for the femoral cortical bone, 21.4% (Ca) and 11.5% (P) for wing cortical bone. (2) The variation for the Ca/P ratio in cortical bone is lower than those for Ca and P separately.This is in agreement with the previous report that the specificity of the Ca/P ratio is better than that of Ca and P concentrations and is more reliable for the diagnosis of bone disorders. The authors suggest that further studies be conducted to establish normal values of Ca, P and Ca/P ratio for polar animals and provide a basis for the diagnosis of bone disorders.

  11. Long-term results of the use of autogenous cortical bone columellas to replace the stapes at stapedectomy.

    Science.gov (United States)

    Bauer, Miklós; Pytel, József; Vóna, Ida; Gerlinger, Imre

    2011-05-01

    The first author has been using an autogenous cortical bone columella to replace the stapes removed during stapedectomy since 1965. The audiograms of 21 of the 271 patients operated on with this method between 1965 and 1989 (i.e. 7.7% of the possible candidates) were available 20-35 (average 26.8) years postoperatively. The operation could be regarded as successful in 20 and unsuccessful in 1 patient in the long run. The audiological data are presented individually as averages of the values obtained at 0.5, 1, 2 and 3 kHz. The averaged data (n = 21): preoperative air conduction, 58.27; bone conduction, 24.46; and air-bone gap, 33.81 dB. Postoperative best air conduction, 19.07; bone conduction, 14.10; and air-bone gap, 4.97 dB. Postoperative recent air conduction, 45.77; bone conduction, 38.45; and air-bone gap, 7.32 dB. The best values were measured 1-8 (average 1.57) years postoperatively. In relation to the postoperative best value, the recent value of the air-bone gap had deteriorated by 2.35 dB, and that of the bone conduction by 24.35 dB. The small air-bone gap indicates that the deterioration of the hearing is mainly caused by the deterioration of the function of the inner ear and not by that of the conductive apparatus. The progression of the deterioration differs individually (0.3-1.6, average 0.93 dB/year) and accelerates with age. This finding seems to be a problem that does not depend on the operative technique. The data show that the autogenous bone columella ensures the same good and lasting results as the alloplastic solutions; moreover, there is no problem with the incus-prosthesis connection.

  12. Blood and Bone Marrow Evaluation for Eosinophilia.

    Science.gov (United States)

    Boyer, Daniel F

    2016-10-01

    Evaluation of peripheral blood and bone marrow for an indication of persistent eosinophilia can be a challenging task because there are many causes of eosinophilia and the morphologic differences between reactive and neoplastic causes are often subtle or lack specificity. The purpose of this review is to provide an overview of the differential diagnosis for eosinophilia, to recommend specific steps for the pathologist evaluating blood and bone marrow, and to emphasize 2 important causes of eosinophilia that require specific ancillary tests for diagnosis: myeloproliferative neoplasm with PDGFRA rearrangement and lymphocyte-variant hypereosinophilic syndrome.

  13. High Insulin Levels in KK-Ay Diabetic Mice Cause Increased Cortical Bone Mass and Impaired Trabecular Micro-Structure

    Directory of Open Access Journals (Sweden)

    Cen Fu

    2015-04-01

    Full Text Available Type 2 diabetes mellitus (T2DM is a chronic disease characterized by hyperglycemia, hyperinsulinemia and complications, including obesity and osteoporosis. Rodents have been widely used to model human T2DM and investigate its effect on the skeleton. We aimed to investigate skeletal alterations in Yellow Kuo Kondo (KK-Ay diabetic mice displaying high insulin and glucose levels. Bone mineral density (BMD, micro-architecture and bone metabolism-related genes were analyzed. The total femoral areal BMD (aBMD, cortical volumetric BMD (vBMD and thickness were significantly increased in KK-Ay mice, while the trabecular vBMD and mineralized bone volume/tissue volume (BV/TV, trabecular thickness and number were decreased compared to C57BL mice. The expression of both osteoblast-related genes, such as osteocalcin (OC, bone sialoprotein, Type I Collagen, osteonectin, RUNX2 and OSX, and osteoclast-related genes, such as TRAP and TCIRG, were up-regulated in KK-Ay mice. Correlation analyses showed that serum insulin levels were positively associated with aBMD, cortical vBMD and thickness and negatively associated with trabecular vBMD and micro-architecture. In addition, serum insulin levels were positively related to osteoblast-related and osteoclast-related gene expression. Our data suggest that high insulin levels in KK-Ay diabetic mice may increase cortical bone mass and impair trabecular micro-structure by up-regulating osteoblast-and osteoclast-related gene expression.

  14. The estrogen receptor-alpha in osteoclasts mediates the protective effects of estrogens on cancellous but not cortical bone.

    Science.gov (United States)

    Martin-Millan, Marta; Almeida, Maria; Ambrogini, Elena; Han, Li; Zhao, Haibo; Weinstein, Robert S; Jilka, Robert L; O'Brien, Charles A; Manolagas, Stavros C

    2010-02-01

    Estrogens attenuate osteoclastogenesis and stimulate osteoclast apoptosis, but the molecular mechanism and contribution of these effects to the overall antiosteoporotic efficacy of estrogens remain controversial. We selectively deleted the estrogen receptor (ER)alpha from the monocyte/macrophage cell lineage in mice (ERalpha(LysM)(-/-)) and found a 2-fold increase in osteoclast progenitors in the marrow and the number of osteoclasts in cancellous bone, along with a decrease in cancellous bone mass. After loss of estrogens these mice failed to exhibit the expected increase in osteoclast progenitors, the number of osteoclasts in bone, and further loss of cancellous bone. However, they lost cortical bone indistinguishably from their littermate controls. Mature osteoclasts from ERalpha(LysM)(-/-) were resistant to the proapoptotic effect of 17beta-estradiol. Nonetheless, the effects of estrogens on osteoclasts were unhindered in mice bearing an ERalpha knock-in mutation that prevented binding to DNA. Moreover, a polymeric form of estrogen that is not capable of stimulating the nuclear-initiated actions of ERalpha was as effective as 17beta-estradiol in inducing osteoclast apoptosis in cells with the wild-type ERalpha. We conclude that estrogens attenuate osteoclast generation and life span via cell autonomous effects mediated by DNA-binding-independent actions of ERalpha. Elimination of these effects is sufficient for loss of bone in the cancellous compartment in which complete perforation of trabeculae by osteoclastic resorption precludes subsequent refilling of the cavities by the bone-forming osteoblasts. However, additional effects of estrogens on osteoblasts, osteocytes, and perhaps other cell types are required for their protective effects on the cortical compartment, which constitutes 80% of the skeleton.

  15. Preliminary estimates of the calcium/phosphorus ratio at different cortical bone sites using synchrotron microCT

    Science.gov (United States)

    Tzaphlidou, M.; Speller, R.; Royle, G.; Griffiths, J.

    2006-04-01

    The Ca/P ratio was measured in cortical bone samples from the femoral neck, front and rear tibia of female rats (1.5 years of age), using synchrotron radiation microtomography. The use of a monoenergetic x-ray beam, as provided by the synchrotron facility, generates accurate 3D maps of the linear attenuation coefficient within the sample and hence gives the ability to map different chemical components. Data sets were taken at 20 keV for each bone sample and calibration phantoms. From the 3D data sets, multiple 2D slices were reconstructed with a slice thickness of ~28 µm and converted to Ca/P ratios using the calibration phantom results. Mean values (M ± SD) for cortical femoral, front and rear tibias are 2.12 ± 0.08, 1.75 ± 0.06 and 1.94 ± 0.07 respectively. These values were compared with those derived from different animals. Differences between the same bone sites from different animals are not significant (0.1 life style and bone use.

  16. Design and Fabrication of 3D printed Scaffolds with a Mechanical Strength Comparable to Cortical Bone to Repair Large Bone Defects.

    Science.gov (United States)

    Roohani-Esfahani, Seyed-Iman; Newman, Peter; Zreiqat, Hala

    2016-01-19

    A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100-150 MPa). Here we design a novel hexagonal architecture for a glass-ceramic scaffold to fabricate an anisotropic, highly porous three dimensional scaffolds with a compressive strength of 110 MPa. Scaffolds with hexagonal design demonstrated a high fatigue resistance (1,000,000 cycles at 1-10 MPa compressive cyclic load), failure reliability and flexural strength (30 MPa) compared with those for conventional architecture. The obtained strength is 150 times greater than values reported for polymeric and composite scaffolds and 5 times greater than reported values for ceramic and glass scaffolds at similar porosity. These scaffolds open avenues for treatment of load bearing bone defects in orthopaedic, dental and maxillofacial applications.

  17. Design and Fabrication of 3D printed Scaffolds with a Mechanical Strength Comparable to Cortical Bone to Repair Large Bone Defects

    Science.gov (United States)

    Roohani-Esfahani, Seyed-Iman; Newman, Peter; Zreiqat, Hala

    2016-01-01

    A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100–150 MPa). Here we design a novel hexagonal architecture for a glass-ceramic scaffold to fabricate an anisotropic, highly porous three dimensional scaffolds with a compressive strength of 110 MPa. Scaffolds with hexagonal design demonstrated a high fatigue resistance (1,000,000 cycles at 1–10 MPa compressive cyclic load), failure reliability and flexural strength (30 MPa) compared with those for conventional architecture. The obtained strength is 150 times greater than values reported for polymeric and composite scaffolds and 5 times greater than reported values for ceramic and glass scaffolds at similar porosity. These scaffolds open avenues for treatment of load bearing bone defects in orthopaedic, dental and maxillofacial applications.

  18. Bone lead (Pb) content at the tibia is associated with thinner distal tibia cortices and lower volumetric bone density in postmenopausal women.

    Science.gov (United States)

    Wong, Andy K O; Beattie, Karen A; Bhargava, Aakash; Cheung, Marco; Webber, Colin E; Chettle, David R; Papaioannou, Alexandra; Adachi, Jonathan D

    2015-10-01

    Conflicting evidence suggests that bone lead or blood lead may reduce areal bone mineral density (BMD). Little is known about how lead at either compartment affects bone structure. This study examined postmenopausal women (N=38, mean age 76 ± 8, body mass index (BMI): 26.74 ± 4.26 kg/m(2)) within the Hamilton cohort of the Canadian Multicentre Osteoporosis Study (CaMos), measuring bone lead at 66% of the non-dominant leg and at the calcaneus using (109)Cadmium X-ray fluorescence. Volumetric BMD and structural parameters were obtained from peripheral quantitative computed tomography images (200 μm in-plane resolution, 2.3 ± 0.5mm slice thickness) of the same 66% site and of the distal 4% site of the tibia length. Blood lead was measured using atomic absorption spectrometry and blood-to-bone lead partition coefficients (PBB, log ratio) were computed. Multivariable linear regression examined each of bone lead at the 66% tibia, calcaneus, blood lead and PBB as related to each of volumetric BMD and structural parameters, adjusting for age and BMI, diabetes or antiresorptive therapy. Regression coefficients were reported along with 95% confidence intervals. Higher amounts of bone lead at the tibia were associated with thinner distal tibia cortices (-0.972 (-1.882, -0.061) per 100 μg Pb/g of bone mineral) and integral volumetric BMD (-3.05 (-6.05, -0.05) per μg Pb/g of bone mineral). A higher PBB was associated with larger trabecular separation (0.115 (0.053, 0.178)), lower trabecular volumetric BMD (-26.83 (-50.37, -3.29)) and trabecular number (-0.08 (-0.14, -0.02)), per 100 μg Pb/g of bone mineral after adjusting for age and BMI, and remained significant while accounting for diabetes or use of antiresorptives. Total lead exposure activities related to bone lead at the calcaneus (8.29 (0.11, 16.48)) and remained significant after age and antiresorptives-adjustment. Lead accumulated in bone can have a mild insult on bone structure; but greater partitioning of lead

  19. Bidirectional axial transmission can improve accuracy and precision of ultrasonic velocity measurement in cortical bone: a validation on test materials.

    Science.gov (United States)

    Bossy, Emmanuel; Talmant, Maryline; Defontaine, Marielle; Patat, Frédéric; Laugier, Pascal

    2004-01-01

    The axial transmission technique uses a linear arrangement of ultrasonic emitters and receivers placed on a same side of a cortical bone site in contact with the skin, involving ultrasonic propagation along the axis of bone. The velocity of the waves radiated from bone has been shown to reflect bone status. The thickness and composition of soft tissue may vary along the length of the bone, between different skeletal sites, or between subjects. Hence, accurate estimates of velocity require first to eliminate the effect of the overlying soft tissue that is traversed by the ultrasound wave. To correct for such bias without measuring soft tissue properties, we designed new ultrasonic probes in the 1-2 MHz frequency range. It is based on propagation along the bone surface in two opposite directions from two sources placed on both sides of a unique group of receivers. The aim is to obtain an unbiased estimate of the velocity without any intermediate calculation of soft tissue properties, such as thickness variation or velocity. Validation tests were performed on academic material such as Perspex or aluminum. We found that head wave velocity values could be biased by more than 10% for inclination of a few degrees between the test specimen surface and the probe. On test materials, the compensation procedure implemented in our probe led to a relative precision error on velocity measurement lower than 0.2 to 0.3%. These results suggest that the correction procedure allows measuring in vivo velocities independently of soft tissue properties.

  20. Compromised cortical bone compartment in type 2 diabetes mellitus patients with microvascular disease

    DEFF Research Database (Denmark)

    Shanbhogue, Vikram Vinod; Hansen, Stinus; Nielsen, Morten Frost Munk

    2016-01-01

    OBJECTIVE AND DESIGN: Patients with type 2 diabetes mellitus (T2D) have an increased fracture risk despite a normal or elevated bone mineral density (BMD). The aim of this cross-sectional in vivo study was to assess parameters of peripheral bone microarchitecture, estimated bone strength and bone......-resolution peripheral quantitative tomography (HR-pQCT) was used to assess bone structure at the non-dominant distal radius and tibia. Estimated bone strength was calculated using finite element analysis. Biochemical markers of bone turnover were measured in all participants. RESULTS: After adjusting for BMI, MVD...

  1. Finite element analysis of dental implant loading on atrophic and non-atrophic cancellous and cortical mandibular bone - a feasibility study.

    Science.gov (United States)

    Marcián, Petr; Borák, Libor; Valášek, Jiří; Kaiser, Jozef; Florian, Zdeněk; Wolff, Jan

    2014-12-18

    The first aim of this study was to assess displacements and micro-strain induced on different grades of atrophic cortical and trabecular mandibular bone by axially loaded dental implants using finite element analysis (FEA). The second aim was to assess the micro-strain induced by different implant geometries and the levels of bone-to-implant contact (BIC) on the surrounding bone. Six mandibular bone segments demonstrating different grades of mandibular bone atrophy and various bone volume fractions (from 0.149 to 0.471) were imaged using a micro-CT device. The acquired bone STL models and implant (Brånemark, Straumann, Ankylos) were merged into a three-dimensional finite elements structure. The mean displacement value for all implants was 3.1 ±1.2 µm. Displacements were lower in the group with a strong BIC. The results indicated that the maximum strain values of cortical and cancellous bone increased with lower bone density. Strain distribution is the first and foremost dependent on the shape of bone and architecture of cancellous bone. The geometry of the implant, thread patterns, grade of bone atrophy and BIC all affect the displacement and micro-strain on the mandible bone. Preoperative finite element analysis could offer improved predictability in the long-term outlook of dental implant restorations.

  2. Does the presence of tumor-induced cortical bone destruction at CT have any prognostic value in newly diagnosed diffuse large B-cell lymphoma?

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Hugo J.A.; Nievelstein, Rutger A.J.; Kwee, Thomas C. [University Medical Center Utrecht, Department of Radiology and Nuclear Medicine, Utrecht (Netherlands); Klerk, John M.H. de [Meander Medical Center, Department of Nuclear Medicine, Amersfoort (Netherlands); Fijnheer, Rob [Meander Medical Center, Department of Hematology, Amersfoort (Netherlands); Heggelman, Ben G.F. [Meander Medical Center, Department of Radiology, Amersfoort (Netherlands); Dubois, Stefan V. [Meander Medical Center, Department of Pathology, Amersfoort (Netherlands)

    2015-05-01

    To determine the prognostic value of tumor-induced cortical bone destruction at computed tomography (CT) in newly diagnosed diffuse large B-cell lymphoma (DLBCL). This retrospective study included 105 patients with newly diagnosed DLBCL who had undergone CT and bone marrow biopsy (BMB) before R-CHOP (rituximab, cyclophosphamide, hydroxydaunorubicin, Oncovin, and prednisolone) chemo-immunotherapy. Cox regression analyses were used to determine the associations of cortical bone status at CT (absence vs. presence of tumor-induced cortical bone destruction), BMB findings (negative vs. positive for lymphomatous involvement), and dichotomized National Comprehensive Cancer Network International Prognostic Index (NCCN-IPI) strata (low risk vs. high risk) with progression-free survival (PFS) and overall survival (OS). Univariate Cox regression analysis indicated that cortical bone status at CT was no significant predictor of either PFS or OS (p = 0.358 and p = 0.560, respectively), whereas BMB findings (p = 0.002 and p = 0.013, respectively) and dichotomized NCCN-IPI risk strata (p = 0.002 and p = 0.003, respectively) were significant predictors of both PFS and OS. In the multivariate Cox proportional hazards model, only the dichotomized NCCN-IPI score was an independent predictive factor of PFS and OS (p = 0.004 and p = 0.003, respectively). The presence of tumor-induced cortical bone destruction at CT was not found to have any prognostic implications in newly diagnosed DLBCL. (orig.)

  3. 腰椎皮质骨钉道螺钉在骨质疏松症患者中应用的三维有限元分析%Biomechanical evaluation of lumbar pedicle screws using cortical bone trajectory in osteoporosis:a finite element study

    Institute of Scientific and Technical Information of China (English)

    邵明昊; 吕飞舟; 马晓生; 夏新雷; 王洪立; 郑超君; 张帆; 姜建元

    2015-01-01

    目的:比较椎弓根皮质骨钉道(cortical bone trajectory,CBT)螺钉和传统椎弓根钉道(traditional trajectory,TT)螺钉抗拔出力、螺钉及椎体稳定性的差异。方法回顾性选取复旦大学附属华山医院2015年3月至9月骨质疏松症患者7例,年龄57~63岁,平均(61.4±3.1)岁,均为女性,骨密度T值均<-2.5 SD。使用Mimics和Abaqus 6.9建立L4椎体模型,选用TT螺钉(直径为6.5 mm、长度为45 mm)和CBT螺钉(直径为5.0 mm、长度为35 mm)模拟置钉,分析并比较两种螺钉的轴向抗拔出力、上下左右载荷情况下螺钉载荷位移比及前屈后伸、轴向及侧屈旋转工况下椎体载荷位移比情况。结果CBT螺钉组的抗拔出力[(1013.2±279.1)N]较TT螺钉组[(1277.1±331.3)N]高出26.04%(t=3.128,P=0.024)。CBT螺钉组在受到上下左右应力时载荷位移比明显大于TT螺钉组(t=3.217,P=0.021;t=3.216,P=0.021;t=3.214,P=0.017;t=3.221, P=0.016)。CBT螺钉组椎体前屈、后伸载荷位移比明显大于TT螺钉组(t=2.733,P=0.034;t=2.712,P=0.031);而TT螺钉组椎体轴向、侧屈旋转载荷位移比较CBT螺钉组高(t=3.941, P=0.011;t=4.432,P=0.007)。结论相比TT螺钉,CBT螺钉具有更强的抗拔出力及螺钉稳定性,且椎体前屈、后伸的稳定性强于TT螺钉固定。CBT螺钉内固定为骨质疏松患者的腰椎手术提供了更多的选择。%ObjectiveThe purpose of the present study was to evaluate the differences of pull-out strength and stability of screw and vertebrae between two models using cortical bone trajectory (CBT) screw and traditional trajectory (TT) screw and provide theoretical basis for the clinical application of CBT screw.Methods Finite element models of L4 vertebrae were builded using Mimics and Abaqus 6.9, according to 7 osteoporotic patients, ranging in age from 57 to 63 years, at average age of (61.4±3.1) years, admitted to

  4. Optimizing finite element predictions of local subchondral bone structural stiffness using neural network-derived density-modulus relationships for proximal tibial subchondral cortical and trabecular bone.

    Science.gov (United States)

    Nazemi, S Majid; Amini, Morteza; Kontulainen, Saija A; Milner, Jaques S; Holdsworth, David W; Masri, Bassam A; Wilson, David R; Johnston, James D

    2017-01-01

    Quantitative computed tomography based subject-specific finite element modeling has potential to clarify the role of subchondral bone alterations in knee osteoarthritis initiation, progression, and pain. However, it is unclear what density-modulus equation(s) should be applied with subchondral cortical and subchondral trabecular bone when constructing finite element models of the tibia. Using a novel approach applying neural networks, optimization, and back-calculation against in situ experimental testing results, the objective of this study was to identify subchondral-specific equations that optimized finite element predictions of local structural stiffness at the proximal tibial subchondral surface. Thirteen proximal tibial compartments were imaged via quantitative computed tomography. Imaged bone mineral density was converted to elastic moduli using multiple density-modulus equations (93 total variations) then mapped to corresponding finite element models. For each variation, root mean squared error was calculated between finite element prediction and in situ measured stiffness at 47 indentation sites. Resulting errors were used to train an artificial neural network, which provided an unlimited number of model variations, with corresponding error, for predicting stiffness at the subchondral bone surface. Nelder-Mead optimization was used to identify optimum density-modulus equations for predicting stiffness. Finite element modeling predicted 81% of experimental stiffness variance (with 10.5% error) using optimized equations for subchondral cortical and trabecular bone differentiated with a 0.5g/cm(3) density. In comparison with published density-modulus relationships, optimized equations offered improved predictions of local subchondral structural stiffness. Further research is needed with anisotropy inclusion, a smaller voxel size and de-blurring algorithms to improve predictions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Perlecan/Hspg2 deficiency alters the pericellular space of the lacunocanalicular system surrounding osteocytic processes in cortical bone.

    Science.gov (United States)

    Thompson, William R; Modla, Shannon; Grindel, Brian J; Czymmek, Kirk J; Kirn-Safran, Catherine B; Wang, Liyun; Duncan, Randall L; Farach-Carson, Mary C

    2011-03-01

    Osteocytes project long, slender processes throughout the mineralized matrix of bone, where they connect and communicate with effector cells. The interconnected cellular projections form the functional lacunocanalicular system, allowing fluid to pass for cell-to-cell communication and nutrient and waste exchange. Prevention of mineralization in the pericellular space of the lacunocanalicular pericellular space is crucial for uninhibited interstitial fluid movement. Factors contributing to the ability of the pericellular space of the lacunocanalicular system to remain open and unmineralized are unclear. Immunofluorescence and immunogold localization by transmission electron microscopy demonstrated perlecan/Hspg2 signal localized to the osteocyte lacunocanalicular system of cortical bone, and this proteoglycan was found in the pericellular space of the lacunocanalicular system. In this study we examined osteocyte lacunocanalicular morphology in mice deficient in the large heparan sulfate proteoglycan perlecan/Hspg2 in this tissue. Ultrastructural measurements with electron microscopy of perlecan/Hspg2-deficient mice demonstrated diminished osteocyte canalicular pericellular area, resulting from a reduction in the total canalicular area. Additionally, perlecan/Hspg2-deficient mice showed decreased canalicular density and a reduced number of transverse tethering elements per canaliculus. These data indicated that perlecan/Hspg2 contributed to the integrity of the osteocyte lacunocanalicular system by maintaining the size of the pericellular space, an essential task to promote uninhibited interstitial fluid movement in this mechanosensitive environment. This work thus identified a new barrier function for perlecan/Hspg2 in murine cortical bone.

  6. Lumbar and radial bone mineral density in children and adolescents with X-linked hypophosphatemia: evaluation with dual X-ray absorptiometry

    Energy Technology Data Exchange (ETDEWEB)

    Shore, R.M.; Poznanski, A.K. [Department of Radiology, Children' s Memorial Hospital, Chicago, IL (United States); Langman, C.B. [Department of Pediatrics, Children' s Memorial Hospital and Northwestern University Medical School, Chicago, IL (United States)

    2000-02-01

    Objective. To evaluate the bone mineral status of children being treated for X-linked hypophosphatemia, including potential differences between cortical bone in the radial diaphysis and combined cortical and trabecular bone in the lumbar spine.Design and patients. Forty-four bone mineral evaluations were performed in 11 children and adolescents with X-linked hypophosphatemia. Bone mineral density (BMD) of the lumbar spine and the radial diaphysis were measured by dual X-ray absorptiometry (DXA), second metacarpal cortical thickness was measured on hand radiographs, and these results were expressed as Z-scores (standard deviations from the mean). Results. For the 11 initial examinations, Z-scores (mean{+-}SD) were: radial BMD, -2.73{+-}1.15, lumbar BMD, +1.28{+-}1.53; and cortical thickness, -2.21{+-}0.95. Lumbar BMD Z-scores were significantly greater than those for radial BMD and cortical thickness. On follow-up examinations there was a mild increase in radial BMD and decrease in lumbar BMD. Although these changes were statistically significant, they were quite small and the discordance between radial and lumbar BMD was not corrected. Conclusions. Children and adolescents who are being treated for X-linked hypophosphatemia manifest a bone mineral disorder characterized by decreased BMD in the appendicular skeleton and increased BMD in the lumbar spine. Although current therapy is successful in its anti-rachitic effects, it does not correct this bone mineral disorder and additional therapeutic trials should be considered. (orig.)

  7. Radioscapholunate arthrodesis with distal excision of the distal scaphoid pole: Intraoperative measurement of range of motion and bone graft coming from a radial cortical flap

    Directory of Open Access Journals (Sweden)

    Cindy Bouvet

    2017-08-01

    Conclusions: Radioscapholunate arthrodesis in the case of radiocarpal arthritis with the use of a bone graft coming from the distal radius demonstrated robust results in terms of pain. The perioperative benefit on mobility was not found during postoperative period. A bone graft using a cortical cover from the distal radius yielded favorable results with regards to bone healing. [Hand Microsurg 2017; 6(2.000: 62-67

  8. Elevated Mechanical Loading When Young Provides Lifelong Benefits to Cortical Bone Properties in Female Rats Independent of a Surgically Induced Menopause

    Science.gov (United States)

    Galley, Matthew R.; Hurd, Andrea L.; Wallace, Joseph M.; Gallant, Maxime A.; Richard, Jeffrey S.; George, Lydia A.

    2013-01-01

    Exercise that mechanically loads the skeleton is advocated when young to enhance lifelong bone health. Whether the skeletal benefits of elevated loading when young persist into adulthood and after menopause are important questions. This study investigated the influence of a surgically induced menopause in female Sprague-Dawley rats on the lifelong maintenance of the cortical bone benefits of skeletal loading when young. Animals had their right forearm extrinsically loaded 3 d/wk between 4 and 10 weeks of age using the forearm axial compression loading model. Left forearms were internal controls and not loaded. Animals were subsequently detrained (restricted to cage activities) for 94 weeks (until age 2 years), with ovariectomy (OVX) or sham-OVX surgery being performed at 24 weeks of age. Loading enhanced midshaft ulna cortical bone mass, structure, and estimated strength. These benefits persisted lifelong and contributed to loaded ulnas having greater strength after detraining. Loading also had effects on cortical bone quality. The benefits of loading when young were not influenced by a surgically induced menopause because there were no interactions between loading and surgery. However, OVX had independent effects on cortical bone mass, structure, and estimated strength at early postsurgery time points (up to age 58 weeks) and bone quality measures. These data indicate skeletal loading when young had lifelong benefits on cortical bone properties that persisted independent of a surgically induced menopause. This suggests that skeletal loading associated with exercise when young may provide lifelong antifracture benefits by priming the skeleton to offset the cortical bone changes associated with aging and menopause. PMID:23782938

  9. Measurement of strain distribution in cortical bone around miniscrew implants used for orthodontic anchorage using digital speckle pattern interferometry

    Science.gov (United States)

    Kumar, Manoj; Agarwal, Rupali; Bhutani, Ravi; Shakher, Chandra

    2016-05-01

    An application of digital speckle pattern interferometry (DSPI) for the measurement of deformations and strain-field distributions developed in cortical bone around orthodontic miniscrew implants inserted into the human maxilla is presented. The purpose of this study is to measure and compare the strain distribution in cortical bone/miniscrew interface of human maxilla around miniscrew implants of different diameters, different implant lengths, and implants of different commercially available companies. The technique is also used to measure tilt/rotation of canine caused due to the application of retraction springs. The proposed technique has high sensitivity and enables the observation of deformation/strain distribution. In DSPI, two specklegrams are recorded corresponding to pre- and postloading of the retraction spring. The DSPI fringe pattern is observed by subtracting these two specklegrams. Optical phase was extracted using Riesz transform and the monogenic signal from a single DSPI fringe pattern. The obtained phase is used to calculate the parameters of interest such as displacement/deformation and strain/stress. The experiment was conducted on a dry human skull fulfilling the criteria of intact dental arches and all teeth present. Eight different miniscrew implants were loaded with an insertion angulation of 45 deg in the inter-radicular region of the maxillary second premolar and molar region. The loading of miniscrew implants was done with force level (150 gf) by nickel-titanium closed-coil springs (9 mm). The obtained results from DSPI reveal that implant diameter and implant length affect the displacement and strain distribution in cortical bone layer surrounding the miniscrew implant.

  10. Evaluating Bone Loss in ISS Astronauts.

    Science.gov (United States)

    Sibonga, Jean D; Spector, Elisabeth R; Johnston, Smith L; Tarver, William J

    2015-12-01

    The measurement of bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) is the Medical Assessment Test used at the NASA Johnson Space Center to evaluate whether prolonged exposure to spaceflight increases the risk for premature osteoporosis in International Space Station (ISS) astronauts. The DXA scans of crewmembers' BMD during the first decade of the ISS existence showed precipitous declines in BMD for the hip and spine after the typical 6-mo missions. However, a concern exists that skeletal integrity cannot be sufficiently assessed solely by DXA measurement of BMD. Consequently, use of relatively new research technologies is being proposed to NASA for risk surveillance and to enhance long-term management of skeletal health in long-duration astronauts. Sibonga JD, Spector ER, Johnston SL, Tarver WJ. Evaluating bone loss in ISS astronauts.

  11. The micro-damage process zone during transverse cortical bone fracture: No ears at crack growth initiation.

    Science.gov (United States)

    Willett, Thomas; Josey, David; Lu, Rick Xing Ze; Minhas, Gagan; Montesano, John

    2017-10-01

    Apply high-resolution benchtop micro-computed tomography (micro-CT) to gain greater understanding and knowledge of the formation of the micro-damage process zone formed during traverse fracture of cortical bone. Bovine cortical bone was cut into single edge notch (bending) fracture testing specimens with the crack on the transverse plane and oriented to grow in the circumferential direction. We used a multi-specimen technique and deformed the specimens to various individual secant modulus loss levels (P-values) up to and including maximum load (Pmax). Next, the specimens were infiltrated with a BaSO4 precipitation stain and scanned at 3.57-μm isotropic voxel size using a benchtop high resolution-micro-CT. Measurements of the micro-damage process zone volume, width and height were made. These were compared with the simple Irwin's process zone model and with finite element models. Electron and confocal microscopy confirmed the formation of BaSO4 precipitate in micro-cracks and other porosity, and an interesting novel mechanism similar to tunneling. Measurable micro-damage was detected at low P values and the volume of the process zone increased according to a second order polynomial trend. Both width and height grew linearly up to Pmax, at which point the process zone cross-section (perpendicular to the plane of the crack) was almost circular on average with a radius of approximately 550µm (approximately one quarter of the unbroken ligament thickness) and corresponding to the shape expected for a biological composite under plane stress conditions. This study reports details of the micro-damage fracture process zone previously unreported for cortical bone. High-resolution micro-CT enables 3D visualization and measurement of the process zone and confirmation that the crack front edge and process zone are affected by microstructure. It is clear that the process zone for the specimens studied grows to be meaningfully large, confirming the need for the J

  12. Intra- and inter-observer variation in histological criteria used in age at death determination based on femoral cortical bone

    DEFF Research Database (Denmark)

    Lynnerup, N; Thomsen, J L; Frohlich, B

    1998-01-01

    been carried out dealing with the intra- and inter-observer error. Furthermore, when such studies have been completed, the statistical tools for assessing variability have not been adequate. This study presents the results of applying simple quantitative statistics on several counts of microscopic...... elements as observed on photographic images of cortical bone, in order to assess intra- and inter-observer error. Overall, substantial error was present at the level of identifying and counting secondary osteons, osteon fragments and Haversian canals. Only secondary osteons can be reliably identified...

  13. Bone Penetration of Amoxicillin and Clavulanic Acid Evaluated by Population Pharmacokinetics and Monte Carlo Simulation▿

    Science.gov (United States)

    Landersdorfer, Cornelia B.; Kinzig, Martina; Bulitta, Jürgen B.; Hennig, Friedrich F.; Holzgrabe, Ulrike; Sörgel, Fritz; Gusinde, Johannes

    2009-01-01

    Amoxicillin (amoxicilline)-clavulanic acid has promising activity against pathogens that cause bone infections. We present the first evaluation of the bone penetration of a beta-lactam by population pharmacokinetics and pharmacodynamic profiling via Monte Carlo simulations. Twenty uninfected patients undergoing total hip replacement received a single intravenous infusion of 2,000 mg/200 mg amoxicillin-clavulanic acid before surgery. Blood and bone specimens were collected. Bone samples were pulverized under liquid nitrogen with a cryogenic mill, including an internal standard. The drug concentrations in serum and total bone were analyzed by liquid chromatography-tandem mass spectrometry. We used NONMEM and S-ADAPT for population pharmacokinetic analysis and a target time of the non-protein-bound drug concentration above the MIC for ≥50% of the dosing interval for near-maximal bactericidal activity in serum. The median of the ratio of the area under the curve (AUC) for bone/AUC for serum was 20% (10th to 90th percentile for between-subject variability [variability], 16 to 25%) in cortical bone and 18% (variability, 11 to 29%) in cancellous bone for amoxicillin and 15% (variability, 11 to 21%) in cortical bone and 10% (variability, 5.1 to 21%) in cancellous bone for clavulanic acid. Analysis in S-ADAPT yielded similar results. The equilibration half-lives between serum and bone were 12 min for amoxicillin and 14 min for clavulanic acid. For a 30-min infusion of 2,000 mg/200 mg amoxicillin-clavulanic acid every 4 h, amoxicillin achieved robust (≥90%) probabilities of target attainment (PTAs) for MICs of ≤12 mg/liter in serum and 2 to 3 mg/liter in bone and population PTAs above 95% against methicillin-susceptible Staphylococcus aureus in bone and serum. The AUC of amoxicillin-clavulanic acid was 5 to 10 times lower in bone than in serum, and amoxicillin-clavulanic acid achieved a rapid equilibrium and favorable population PTAs against pathogens commonly

  14. Inflammatory response and bone healing capacity of two porous calcium phosphate ceramics in critical size cortical bone defects.

    Science.gov (United States)

    Chatterjea, Anindita; van der Stok, Johan; Danoux, Charlène B; Yuan, Huipin; Habibovic, Pamela; van Blitterswijk, Clemens A; Weinans, Harrie; de Boer, Jan

    2014-05-01

    In the present study, two open porous calcium phosphate ceramics, β-tricalcium phosphate (β-TCP), and hydroxyapatite (HA) were compared in a critical-sized femoral defect in rats. Previous comparisons of these two ceramics showed significantly greater osteoinductive potential of β-TCP upon intramuscular implantation and a better performance in a spinal fusion model in dogs. Results of the current study also showed significantly more bone formation in defects grafted with β-TCP compared to HA; however, both the ceramics were not capable of increasing bone formation to such extend that it bridges the defect. Furthermore, a more pronounced degradation of β-TCP was observed as compared to HA. Progression of inflammation and initiation of new bone formation were assessed for both materials at multiple time points by histological and fluorochrome-based analyses. Until 12 days postimplantation, a strong inflammatory response in absence of new bone formation was observed in both ceramics, without obvious differences between the two materials. Four weeks postimplantation, signs of new bone formation were found in both β-TCP and HA. At 6 weeks, inflammation had subsided in both ceramics while bone deposition continued. In conclusion, the two ceramics differed in the amount of bone formed after 8 weeks of implantation, whereas no differences were found in the duration of the inflammatory phase after implantation or initiation of new bone formation.

  15. MicroCT evaluation of bone mineral density loss in human bones

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, Liebert P.; Braz, Delson; Lopes, Ricardo T. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Lab. de Instrumentacao Nuclear]. E-mails: lnogueira@con.ufrj.br; Barroso, Regina C.; Oliveira, Luis F. [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil). Inst. de Fisica]. E-mail: cely@uerj.br

    2007-07-01

    Bone is a connective tissue largely composed of an organic protein, collagen and the inorganic mineral hydroxyapatite [Ca{sub 10}(PO{sub 4}){sub 6}OH{sub 2}], which combine to provide a mechanical and supportive role in the body. Depending on the orientation of collagen fibers, two types of bone can be distinguished: trabecular and cortical bone. Degree of mineralization is considered an important feature of bone quality. Changes in the degree of mineralization is generally due to osteoporosis, but many recent studies have already shown that alterations in degree of mineralization can occur due to a large variety of factors. The transmission X-ray microtomography is one of the most popular methods, which provides the spatial distribution of the total absorption coefficient inside the sample. The aim of this study was to investigate the suitability of using microCT as a supplementary tool for the diagnosis of the health status of human bones. Eleven samples were constructed simulating the physiological range of bone mineral density (BMD) found in cortical human bone. The samples represent healthy mixtures of swine compact bone dried at room temperature, powdered and mixed with fat (0 - 100 % by mass). The samples were imaged by a microfocus tube (Fein-Focus) with focal size of about 60 {mu}m ({+-}5%), and a CCD camera (0.143 mm pixel size) coupled with an intensifier tube with fluoroscope screen at the Nuclear Instrumentation Laboratory (COPPE/UFRJ), Brazil. The images were reconstructed and treated with suitable software developed at the Nuclear Instrumentation Laboratory. The mineral content in cortical bone is defined by the volume of dry, fat-free bone per unit bulk volume of the bone. The volumes were calculated from the bone density using the relationship between volume and density. The densities of fat and bone were taken to be 0.95 g.cm{sup -3} and 1.92 g.cm{sup -3} respectively. The correlation of the measured absorption coefficient with the mineral content

  16. Preclinical evaluation of injectable bone substitute materials.

    Science.gov (United States)

    Bongio, Matilde; van den Beucken, Jeroen J J P; Leeuwenburgh, Sander C G; Jansen, John A

    2015-03-01

    Injectable bone substitutes (IBSs) represent an attractive class of ready-to-use biomaterials, both ceramic- and polymer-based, as they offer the potential benefit of minimally invasive surgery and optimal defect filling. Although in vitro assessments are the first step in the process of development, the safety and efficacy of an IBS strongly depend on validated preclinical research prior to clinical trials. However, the selection of a suitable preclinical model for performance evaluation of an IBS remains a challenge, as no gold standard exists to define the best animal model. In order to succeed in this attempt, we identified three stages of development, including (a) proof-of-principle, (b) predictive validity and (c) general scientific legitimacy, and the respective criteria that should be applied for such selection. The second part of this review provides an overview of commonly used animals for IBSs. Specifically, scientific papers published between January 1996 and March 2012 were retrieved that report the use of preclinical models for the evaluation of IBSs in situations requiring bone healing and bone augmentation. This review is meant not only to describe the currently available preclinical models for IBS application, but also to address critical considerations of such multi-factorial evaluation models (including animal species, strain, age, anatomical site, defect size and type of bone), which can be indicative but in most cases edge away from the human reality. Consequently, the ultimate goal is to guide researchers toward a more careful and meaningful interpretation of the results of experiments using animal models and their clinical applications. Copyright © 2012 John Wiley & Sons, Ltd.

  17. Cortical and trabecular bone at the radius and tibia in male and female adolescents with Down syndrome: a peripheral quantitative computed tomography (pQCT) study.

    Science.gov (United States)

    González-Agüero, A; Vicente-Rodríguez, G; Gómez-Cabello, A; Casajús, J A

    2013-03-01

    We aimed to describe the structure and strength of the tibia and radius of adolescents with Down syndrome. We observed that despite higher levels of volumetric bone mineral density in determined skeletal sites, they are at higher risk of developing osteoporotic fractures in the future due to their lower bone strength indexes. The aims of the study were to describe the cortical and trabecular volumetric bone mineral density (vBMD), bone mineral content (BMC), area, and bone strength in adolescents with Down syndrome (DS) and to compare them with adolescents without disabilities. Thirty adolescents (11 girls) with DS and 28 without disabilities (10 girls) participated in the study. Peripheral quantitative computed tomography measurements were taken at proximal and distal sites of the tibia and radius. Values of total, trabecular, and cortical BMC; vBMD; and area were obtained of each scan. Cortical thickness and endosteal and periosteal circumferences were also measured, and different bone strength indexes were calculated. Student's t tests were applied between groups. The DS group showed greater vBMD at distal radius, BMC at proximal radius, and total and cortical vBMD at proximal tibia. The non-DS group showed higher total and trabecular area at the distal radius and total, cortical, and trabecular BMC and area at distal tibia. Higher values of periosteal and endosteal circumference and bone strength were also found in non-DS group. From these results, it can be believed that even with higher vBMD in determined skeletal sites, adolescents with DS are at higher risk of suffering bone fractures due to an increased fragility by lower resistance to load bending or torsion.

  18. Simulation of acoustic guided wave propagation in cortical bone using a semi-analytical finite element method.

    Science.gov (United States)

    Pereira, Daniel; Haiat, Guillaume; Fernandes, Julio; Belanger, Pierre

    2017-04-01

    Axial transmission techniques have been extensively studied for cortical bone quality assessment. However, the modeling of ultrasonic guided waves propagation in such a complex medium remains challenging. The aim of this paper is to develop a semi-analytical finite element method to simulate the propagation of guided waves in an irregular, multi-layer, and heterogeneous bone cross-section modeled with anisotropic and viscoelastic material properties. The accuracy of the simulations was verified against conventional time-domain three-dimensional finite element. The method was applied in the context of axial transmission in bone to investigate the feasibility of first arrival signal (FAS) to monitor degradation of intracortical properties at low frequency. Different physiopathological conditions for the intracortical region, varying from healthy to osteoporotic, were monitored through FAS velocity using a 10-cycle tone burst excitation centered at 32.5 kHz. The results show that the variation in FAS velocity is mainly associated with four of the eight modes supported by the waveguide, varying with velocity values between 550 and 700 m/s along the different scenarios. Furthermore, the FAS velocity is shown to be associated with the group velocity of the mode with the highest relative amplitude contribution at each studied scenario. However, because of the evolution of the mode with the highest contribution, the FAS velocity is shown to be limited to discriminate intracortical bone properties at low frequency.

  19. Predicting Hip Fracture Type With Cortical Bone Mapping (CBM) in the Osteoporotic Fractures in Men (MrOS) Study.

    Science.gov (United States)

    Treece, Graham M; Gee, Andrew H; Tonkin, Carol; Ewing, Susan K; Cawthon, Peggy M; Black, Dennis M; Poole, Kenneth E S

    2015-11-01

    Hip fracture risk is known to be related to material properties of the proximal femur, but fracture prediction studies adding richer quantitative computed tomography (QCT) measures to dual-energy X-ray (DXA)-based methods have shown limited improvement. Fracture types have distinct relationships to predictors, but few studies have subdivided fracture into types, because this necessitates regional measurements and more fracture cases. This work makes use of cortical bone mapping (CBM) to accurately assess, with no prior anatomical presumptions, the distribution of properties related to fracture type. CBM uses QCT data to measure the cortical and trabecular properties, accurate even for thin cortices below the imaging resolution. The Osteoporotic Fractures in Men (MrOS) study is a predictive case-cohort study of men over 65 years old: we analyze 99 fracture cases (44 trochanteric and 55 femoral neck) compared to a cohort of 308, randomly selected from 5994. To our knowledge, this is the largest QCT-based predictive hip fracture study to date, and the first to incorporate CBM analysis into fracture prediction. We show that both cortical mass surface density and endocortical trabecular BMD are significantly different in fracture cases versus cohort, in regions appropriate to fracture type. We incorporate these regions into predictive models using Cox proportional hazards regression to estimate hazard ratios, and logistic regression to estimate area under the receiver operating characteristic curve (AUC). Adding CBM to DXA-based BMD leads to a small but significant (p fracture, with AUC increasing from 0.78 to 0.79, assessed using leave-one-out cross-validation. For specific fracture types, the improvement is more significant (p fractures and 0.76 to 0.82 for femoral neck fractures. In contrast, adding DXA-based BMD to a CBM-based predictive model does not result in any significant improvement. © 2015 The Authors. Journal of Bone and Mineral Research published by

  20. Eldecalcitol, a vitamin D analog, reduces bone turnover and increases trabecular and cortical bone mass, density, and strength in ovariectomized cynomolgus monkeys.

    Science.gov (United States)

    Smith, Susan Y; Doyle, Nancy; Boyer, Marilyne; Chouinard, Luc; Saito, Hitoshi

    2013-11-01

    Vitamin D insufficiency is common in elderly people worldwide, and intake of supplementary calcium and vitamin D is recommended to those with a high risk of fracture. Several clinical studies and meta-analyses have shown that calcium and vitamin D supplementation reduces osteoporotic fractures, and a strong correlation exists between vitamin D status and fracture risk. Vitamin D supplementations improve calcium balance in the body; however, it remains unclear whether vitamin D directly affects bone metabolism. Recently, eldecalcitol (ELD), an active form of vitamin D analog, has been approved for the treatment of osteoporosis in Japan. A 3-year clinical trial showed ELD treatment increased lumbar spine bone mineral density (BMD) and reduced fracture risk in patients with osteoporosis. To evaluate the mechanism of ELD action in bone remodeling, ovariectomized cynomolgus monkeys were treated with 0.1 or 0.3μg/day of ELD for 6months. This treatment increased lumbar BMD by 4.4% and 10.2%, respectively, and suppressed ovariectomy-induced increases in bone turnover markers compared to OVX-vehicle control. Histomorphometric analysis of bone revealed that both bone formation parameters and bone resorption parameters in the trabecular bone of the lumbar vertebrae were suppressed by ELD treatment. ELD treatment also improved biomechanical properties of the lumbar vertebrae and the femoral neck in the ovariectomized cynomolgus monkeys. These results indicate that, in a bone-remodeling animal model, ELD increases BMD and improves bone biomechanical properties by normalizing bone turnover. Therefore, ELD has a direct and potentially beneficial effect on bone metabolism. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  1. Accounting for beta-particle energy loss to cortical bone via paired-image radiation transport (PIRT).

    Science.gov (United States)

    Shah, Amish P; Rajon, Didier A; Patton, Phillip W; Jokisch, Derek W; Bolch, Wesley E

    2005-05-01

    Current methods of skeletal dose assessment in both medical physics (radionuclide therapy) and health physics (dose reconstruction and risk assessment) rely heavily on a single set of bone and marrow cavity chord-length distributions in which particle energy deposition is tracked within an infinite extent of trabecular spongiosa, with no allowance for particle escape to cortical bone. In the present study, we introduce a paired-image radiation transport (PIRT) model which provides a more realistic three-dimensional (3D) geometry for particle transport in the skeletal site at both microscopic and macroscopic levels of its histology. Ex vivo CT scans were acquired of the pelvis, cranial cap, and individual ribs excised from a 66-year male cadaver (BMI of 22.7 kg m(-2)). For the three skeletal sites, regions of trabecular spongiosa and cortical bone were identified and segmented. Physical sections of interior spongiosa were taken and subjected to microCT imaging. Voxels within the resulting microCT images were then segmented and labeled as regions of bone trabeculae, endosteum, active marrow, and inactive marrow through application of image processing algorithms. The PIRT methodology was then implemented within the EGSNRC radiation transport code whereby electrons of various initial energies are simultaneously tracked within both the ex vivo CT macroimage and the CT microimage of the skeletal site. At initial electron energies greater than 50-200 keV, a divergence in absorbed fractions to active marrow are noted between PIRT model simulations and those estimated under existing techniques of infinite spongiosa transport. Calculations of radionuclide S values under both methodologies imply that current chord-based models may overestimate the absorbed dose to active bone marrow in these skeletal sites by 0% to 27% for low-energy beta emitters (33P, 169Er, and 177Lu), by approximately 4% to 49% for intermediate-energy beta emitters (153Sm, 186Re, and 89Sr), and by

  2. Microstructural and Photoacoustic Infrared Spectroscopic Studies of Human Cortical Bone with Osteogenesis Imperfecta

    Science.gov (United States)

    Gu, Chunju; Katti, Dinesh R.; Katti, Kalpana S.

    2016-04-01

    The molecular basis of bone disease osteogenesis imperfecta (OI) and the mineralization of hydroxyapatite in OI bone have been of significant research interest. To further investigate the mechanism of OI disease and bone mineralization, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, and x-ray diffraction (XRD) are used in the present study to describe the structural and compositional differences between OI and healthy bone. OI bone exhibits more porous, fibrous features, abnormal collagen fibrils, and abnormal mineral deposits. Likewise, photoacoustic-FTIR experiments indicate an aberrant collagen structure and an altered mineral structure in OI. In contrast, there is neither significant difference in the non-collagenous proteins (NCPs) composition observed nor apparent change in the crystal structure between OI and healthy bone minerals as shown in XRD and energy-dispersive x-ray spectroscopy (EDS) results. This observation indicates that the biomineralization process is more controlled by the bone cells and non-collagenous phosphorylated proteins. The present study also confirms that there is an orientational influence on the stoichiometry of the mineral in OI bone. Also, a larger volume of the hydrated layer in the transverse plane than the longitudinal plane of the mineral crystal structure is proposed. The appearance of a new C-S band in the FTIR spectra in OI bone suggests the substitution of glycine by cysteine in collagen molecules or/and an increased amount of cysteine-rich osteonectin that relates to mineral nucleation and mineral crystal formation.

  3. Correlation between longitudinal, circumferential, and radial moduli in cortical bone: effect of mineral content.

    Science.gov (United States)

    Macione, J; Depaula, C A; Guzelsu, N; Kotha, S P

    2010-07-01

    Previous studies indicate that changes in the longitudinal elastic properties of bone due to changes in mineral content are related to the longitudinal strength of bone tissue. Changes in mineral content are expected to affect bone tissue mechanical properties along all directions, albeit to different extents. However, changes in tissue mechanical properties along the different directions are expected to be correlated to one another. In this study, we investigate if radial, circumferential, and longitudinal moduli are related in bone tissue with varying mineral content. Plexiform bovine femoral bone samples were treated in fluoride ion solutions for a period of 3 and 12 days to obtain bones with 20% and 32% lower effective mineral contents. Transmission ultrasound velocities were obtained in the radial, circumferential, and longitudinal axes of bone and combined with measured densities to obtain corresponding tensorial moduli. Results indicate that moduli decreased with fluoride ion treatments and were significantly correlated to one another (r(2) radial vs. longitudinal = 0.80, r(2) circumferential vs. longitudinal = 0.90, r(2) radial vs. circumferential = 0.85). Densities calculated from using ultrasound parameters, acoustic impedance and transmission velocities, were moderately correlated to those measured by the Archimedes principle (r(2)=0.54, p<0.01). These results suggest that radial and circumferential ultrasound measurements could be used to determine the longitudinal properties of bone and that ultrasound may not be able to predict in vitro densities of bones containing unbonded mineral. Published by Elsevier Ltd.

  4. Does weight gain induce cortical and trabecular bone regain in anorexia nervosa? A two-year prospective study.

    Science.gov (United States)

    Milos, Gabriella; Spindler, Anja; Rüegsegger, Peter; Hasler, Gregor; Schnyder, Ulrich; Laib, Andres; Gallo, Luigi M; Uebelhart, Daniel; Häuselmann, Hansjörg

    2007-11-01

    This prospective study examines bone density and structure over a two-year time period in women with anorexia nervosa (AN) under weight gain treatment. Twenty-four women with AN were examined at baseline and at two annual follow-up examinations. In 9 AN patients BMI increased whereas in 15 it remained unchanged or decreased. Dual energy X-ray absorptiometry (DXA) was performed on the lumbar spine, the femoral neck and the whole hip and three-dimensional peripheral quantitative computer tomography (3D-pQCT) was performed on the ultradistal radius. ANOVAs for repeated measures were used to examine change over time in BMI and bone parameters. At baseline, patients with increased BMI had significantly higher bone density of femoral neck and total hip, and higher levels in all 3D-pQCT parameters of the ultradistal radius, compared to the group with unchanged or decreased BMI. The two groups did not differ at baseline in bone density of the spine. ANOVAs showed that bone density of the total hip increased significantly and that overall bone density (D100), the density of the trabecular area (D.Trab.) and the cortical thickness (C.Th.) in the ultradistal radius decreased significantly. Group x time interactions showed that changes over time were different in the two groups with regard to spine density and in the parameters D100, D.Trab. and C.Th. of the ultradistal radius. In the group with increased BMI the spine density dropped at the first follow-up whereas at the second follow-up it rose again to baseline. Patients with unchanged or decreased BMI showed a small but steady increase in spine density. The group changes of D100, D.Trab. and C.Th. of the ultradistal radius all followed the same pattern. Bone mineral density at all locations measured with both technologies (DXA and 3D-pQCT) did not vary according to BMI changes. The course of bone density and structure at different locations was different, and, despite weight increase, bone regain appeared to need different

  5. High-calcium diet modulates effects of long-term prolactin exposure on the cortical bone calcium content in ovariectomized rats.

    Science.gov (United States)

    Charoenphandhu, Narattaphol; Tudpor, Kukiat; Thongchote, Kanogwun; Saengamnart, Wasana; Puntheeranurak, Supaporn; Krishnamra, Nateetip

    2007-02-01

    High physiological prolactin induced positive calcium balance by stimulating intestinal calcium absorption, reducing renal calcium excretion, and increasing bone calcium deposition in female rats. Although prolactin-induced increase in trabecular bone calcium deposition was absent after ovariectomy, its effects on cortical bones were still controversial. The present investigation, therefore, aimed to study the effect of in vivo long-term high physiological prolactin induced by either anterior pituitary (AP) transplantation or 2.5 mg/kg prolactin injection on cortical bones in ovariectomized rats. Since the presence of prolactin receptors (PRLR) in different bones of normal adult rats has not been reported, we first determined mRNA expression of both short- and long-form PRLRs at the cortical sites (tibia and femur) and trabecular sites (calvaria and vertebrae) by using the RT-PCR. Our results showed the mRNA expression of both PRLR isoforms with predominant long form at all sites. However, high prolactin levels induced by AP transplantation in normal rats did not have any effect on the femoral bone mineral density or bone mineral content. By using (45)Ca kinetic study, 2.5 mg/kg prolactin did not alter bone formation, bone resorption, calcium deposition, and total calcium content in tibia and femur of adult ovariectomized rats. AP transplantation also had no effect on the cortical total calcium content in adult ovariectomized rats. Because previous work showed that the effects of prolactin were age dependent and could be modulated by high-calcium diet, interactions between prolactin and these two parameters were investigated. The results demonstrated that 2.0% wt/wt high-calcium diet significantly increased the tibial total calcium content in 9-wk-old young AP-grafted ovariectomized rats but decreased the tibial total calcium content in 22-wk-old adult rats. As for the vertebrae, the total calcium contents in both young and adult rats were not changed by high

  6. Latarjet Fixation: A Cadaveric Biomechanical Study Evaluating Cortical and Cannulated Screw Fixation.

    Science.gov (United States)

    Alvi, Hasham M; Monroe, Emily J; Muriuki, Muturi; Verma, Rajat N; Marra, Guido; Saltzman, Matthew D

    2016-04-01

    Attritional bone loss in patients with recurrent anterior instability has successfully been treated with a bone block procedure such as the Latarjet. It has not been previously demonstrated whether cortical or cancellous screws are superior when used for this procedure. To assess the strength of stainless steel cortical screws versus stainless steel cannulated cancellous screws in the Latarjet procedure. Controlled laboratory study. Ten fresh-frozen matched-pair shoulder specimens were randomized into 2 separate fixation groups: (1) 3.5-mm stainless steel cortical screws and (2) 4.0-mm stainless steel partially threaded cannulated cancellous screws. Shoulder specimens were dissected free of all soft tissue and a 25% glenoid defect was created. The coracoid process was osteomized, placed at the site of the glenoid defect, and fixed in place with 2 parallel screws. All 10 specimens failed by screw cutout. Nine of 10 specimens failed by progressive displacement with an increased number of cycles. One specimen in the 4.0-mm screw group failed by catastrophic failure on initiation of the testing protocol. The 3.5-mm screws had a mean of 274 cycles (SD, ±171 cycles; range, 10-443 cycles) to failure. The 4.0-mm screws had a mean of 135 cycles (SD, ±141 cycles; range, 0-284 cycles) to failure. There was no statistically significant difference between the 2 types of screws for cycles required to cause failure (P = .144). There was no statistically significant difference in energy or cycles to failure when comparing the stainless steel cortical screws versus partially threaded cannulated cancellous screws. Latarjet may be performed using cortical or cancellous screws without a clear advantage of either option.

  7. Re-evaluation of bone pain in patients with type 1 Gaucher disease suggests that bone crises occur in small bones as well as long bones.

    Science.gov (United States)

    Baris, Hagit N; Weisz Hubshman, Monika; Bar-Sever, Zvi; Kornreich, Liora; Shkalim Zemer, Vered; Cohen, Ian J

    2016-09-01

    Bone crises in type 1 Gaucher disease are reported in long bones and occasionally in weight bearing bones and other bones, but rarely in small bones of the hands and feet. We retrospectively examined the incidence of bone pain in patients followed at the Rabin Medical Center, Israel, before and following the initiation of enzyme replacement therapy (ERT) and evaluated them for bone crises. Of 100 type I Gaucher disease patients, 30 (30%) experienced one or more bone crises. Small bone crises represented 31.5% of all bone crises and were always preceded by crises in other bones. While the incidence of long bone crises reduced after the initiation of ERT, small bone crises increased. Almost 60% of patients with bone crises were of the N370S/84GG genotype suggesting a greater susceptibility of N370S/84GG patients to severe bone complications. These patients also underwent the greatest number of splenectomies (70.6% of splenectomised patients). Splenectomised patients showed a trend towards increased long and small bone crises after surgery. Active investigation of acute pain in the hands and feet in patients in our cohort has revealed a high incidence of small bone crises. Physicians should consider imaging studies to investigate unexplained pain in these areas.

  8. Genome-wide association meta-analysis of cortical bone mineral density unravels allelic heterogeneity at the RANKL locus and potential pleiotropic effects on bone.

    Directory of Open Access Journals (Sweden)

    Lavinia Paternoster

    2010-11-01

    Full Text Available Previous genome-wide association (GWA studies have identified SNPs associated with areal bone mineral density (aBMD. However, this measure is influenced by several different skeletal parameters, such as periosteal expansion, cortical bone mineral density (BMD(C cortical thickness, trabecular number, and trabecular thickness, which may be under distinct biological and genetic control. We have carried out a GWA and replication study of BMD(C, as measured by peripheral quantitative computed tomography (pQCT, a more homogenous and valid measure of actual volumetric bone density. After initial GWA meta-analysis of two cohorts (ALSPAC n = 999, aged ∼15 years and GOOD n = 935, aged ∼19 years, we attempted to replicate the BMD(C associations that had p<1×10(-5 in an independent sample of ALSPAC children (n = 2803 and in a cohort of elderly men (MrOS Sweden, n = 1052. The rs1021188 SNP (near RANKL was associated with BMD(C in all cohorts (overall p = 2×10(-14, n = 5739. Each minor allele was associated with a decrease in BMD(C of ∼0.14SD. There was also evidence for an interaction between this variant and sex (p = 0.01, with a stronger effect in males than females (at age 15, males -6.77mg/cm(3 per C allele, p = 2×10(-6; females -2.79 mg/cm(3 per C allele, p = 0.004. Furthermore, in a preliminary analysis, the rs1021188 minor C allele was associated with higher circulating levels of sRANKL (p<0.005. We show this variant to be independent from the previously aBMD associated SNP (rs9594738 and possibly from a third variant in the same RANKL region, which demonstrates important allelic heterogeneity at this locus. Associations with skeletal parameters reflecting bone dimensions were either not found or were much less pronounced. This finding implicates RANKL as a locus containing variation associated with volumetric bone density and provides further insight into the mechanism by which the RANK/RANKL/OPG pathway

  9. Age-related changes in the plasticity and toughness of human cortical bone at multiple length-scales

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, Elizabeth A.; Schaible, Eric; Bale, Hrishikesh; Barth, Holly D.; Tang, Simon Y.; Reichert, Peter; Busse, Bjoern; Alliston, Tamara; Ager III, Joel W.; Ritchie, Robert O.

    2011-08-10

    The structure of human cortical bone evolves over multiple length-scales from its basic constituents of collagen and hydroxyapatite at the nanoscale to osteonal structures at nearmillimeter dimensions, which all provide the basis for its mechanical properties. To resist fracture, bone’s toughness is derived intrinsically through plasticity (e.g., fibrillar sliding) at structural-scales typically below a micron and extrinsically (i.e., during crack growth) through mechanisms (e.g., crack deflection/bridging) generated at larger structural-scales. Biological factors such as aging lead to a markedly increased fracture risk, which is often associated with an age-related loss in bone mass (bone quantity). However, we find that age-related structural changes can significantly degrade the fracture resistance (bone quality) over multiple lengthscales. Using in situ small-/wide-angle x-ray scattering/diffraction to characterize sub-micron structural changes and synchrotron x-ray computed tomography and in situ fracture-toughness measurements in the scanning electron microscope to characterize effects at micron-scales, we show how these age-related structural changes at differing size-scales degrade both the intrinsic and extrinsic toughness of bone. Specifically, we attribute the loss in toughness to increased non-enzymatic collagen cross-linking which suppresses plasticity at nanoscale dimensions and to an increased osteonal density which limits the potency of crack-bridging mechanisms at micron-scales. The link between these processes is that the increased stiffness of the cross-linked collagen requires energy to be absorbed by “plastic” deformation at higher structural levels, which occurs by the process of microcracking.

  10. Intensive glycemic control and thiazolidinedione use: effects on cortical and trabecular bone at the radius and tibia.

    Science.gov (United States)

    Schwartz, Ann V; Vittinghoff, Eric; Margolis, Karen L; Scibora, Lesley M; Palermo, Lisa; Ambrosius, Walter T; Hue, Trisha F; Ensrud, Kristine E

    2013-05-01

    Factors that contribute to bone fragility in type 2 diabetes are not well understood. We assessed the effects of intensive glycemic control, thiazolidinediones (TZDs), and A1C levels on bone geometry and strength at the radius and tibia. In a substudy of the Action to Control Cardiovascular Risk in Diabetes trial, peripheral quantitative computed tomographic (pQCT) scans of the radius and tibia were obtained 2 years after randomization on 73 participants (intensive n = 35, standard n = 38). TZD use and A1C levels were measured every 4 months during the trial. Effects of intervention assignment, TZD use, and A1C on pQCT parameters were assessed in linear regression models. Intensive, compared with standard, glycemic control was associated with 1.3 % lower cortical volumetric BMD at the tibia in men (p = 0.02) but not with other pQCT parameters. In women, but not men, each additional year of TZD use was associated with an 11 % lower polar strength strain index (SSIp) at the radius (p = 0.04) and tibia (p = 0.002) in models adjusted for A1C levels. In women, each additional 1 % increase in A1C was associated with an 18 % lower SSIp at the ultradistal radius (p = 0.04) in models adjusted for TZD use. There was no consistent evidence of an effect of intensive, compared with standard, glycemic control on bone strength at the radius or tibia. In women, TZD use may reduce bone strength at these sites. Higher A1C may also be associated with lower bone strength at the radius, but not tibia, in women.

  11. Non-invasive predictors of human cortical bone mechanical properties: T(2-discriminated H NMR compared with high resolution X-ray.

    Directory of Open Access Journals (Sweden)

    R Adam Horch

    Full Text Available Recent advancements in magnetic resonance imaging (MRI have enabled clinical imaging of human cortical bone, providing a potentially powerful new means for assessing bone health with molecular-scale sensitivities unavailable to conventional X-ray-based diagnostics. To this end, (1H nuclear magnetic resonance (NMR and high-resolution X-ray signals from human cortical bone samples were correlated with mechanical properties of bone. Results showed that (1H NMR signals were better predictors of yield stress, peak stress, and pre-yield toughness than were the X-ray derived signals. These (1H NMR signals can, in principle, be extracted from clinical MRI, thus offering the potential for improved clinical assessment of fracture risk.

  12. Irradiation conditions for fiber laser bonding of HAp-glass ceramics with bovine cortical bone.

    Science.gov (United States)

    Tadano, Shigeru; Yamada, Satoshi; Kanaoka, Masaru

    2014-01-01

    Orthopedic implants are widely used to repair bones and to replace articulating joint surfaces. It is important to develop an instantaneous technique for the direct bonding of bone and implant materials. The aim of this study was to develop a technique for the laser bonding of bone with an implant material like ceramics. Ceramic specimens (10 mm diameter and 1 mm thickness) were sintered with hydroxyapatite and MgO-Al2O3-SiO2 glass powders mixed in 40:60 wt% proportions. A small hole was bored at the center of a ceramic specimen. The ceramic specimen was positioned onto a bovine bone specimen and a 5 mm diameter area of the ceramic specimen was irradiated using a fiber laser beam (1070-1080 nm wavelength). As a result, the bone and the ceramic specimens bonded strongly under the irradiation conditions of a 400 W laser power and a 1.0 s exposure time. The maximum shear strength was 5.3 ± 2.3 N. A bonding substance that penetrated deeply into the bone specimen was generated around the hole in the ceramic specimen. On using the fiber laser, the ceramic specimen instantaneously bonded to the bone specimen. Further, the irradiation conditions required for the bonding were investigated.

  13. Three-Dimensional Analysis of the Contact Pattern between the Cortical Bone and Femoral Prosthesis after Cementless Total Hip Arthroplasty

    Directory of Open Access Journals (Sweden)

    Hiroshi Wada

    2016-01-01

    Full Text Available The cementless stem Excia (B. Braun, Melsungen, Germany implant has a rectangular cross-sectional shape with back-and-forth flanges and a plasma-sprayed, dicalcium phosphate dihydrate coating from the middle to proximal portion to increase initial fixation and early bone formation. Here, the conformity of the Excia stem to the femoral canal morphology was three-dimensionally assessed using computed tomography. Forty-three patients (45 hips were examined after primary total hip arthroplasty with a mean follow-up of 27 ± 3 months (range: 24–36 months. Spot welds occurred at zone 2 in 16 hips and at zone 6 in 24 hips, with 83% (20/24 hips of those occurring within 3 months after surgery. First- (n=12 hips, second- (n=32, and third- (n=1 degree stress shielding were observed. The stem was typically in contact with the cortical bone in the anterolateral mid-portion (100% and posteromedial distal portions (85%. Stress shielding did not progress, even in cases where the stems were in contact with the distal portions. The anterior flange was in contact with the bone in all cases. The stability of the mid-lateral portion with the dicalcium phosphate dihydrate coating and the anterior flange may have inhibited the progression of stress shielding beyond the second degree.

  14. Evaluation of an intramedullary bone stabilization system using a light-curable monomer in sheep.

    Science.gov (United States)

    Zani, Brett G; Baird, Rose; Stanley, James R L; Markham, Peter M; Wilke, Markus; Zeiter, Stephan; Beck, Aswin; Nehrbass, Dirk; Kopia, Gregory A; Edelman, Elazer R; Rabiner, Robert

    2016-02-01

    Percutaneous intramedullary fixation may provide an ideal method for stabilization of bone fractures, while avoiding the need for large tissue dissections. Tibiae in 18 sheep were treated with an intramedullary photodynamic bone stabilization system (PBSS) that comprised a polyethylene terephthalate (Dacron) balloon filled with a monomer, cured with visible light in situ, and then harvested at 30, 90, or 180 days. In additional 40 sheep, a midshaft tibial osteotomy was performed and stabilized with external fixators or external fixators combined with the PBSS and evaluated at 8, 12, and 26 weeks. Healing and biocompatibility were evaluated by radiographic analysis, micro-computed tomography, and histopathology. In nonfractured sheep tibiae, PBSS implants conformably filled the medullary canal, while active cortical bone remodeling and apposition of new periosteal and/or endosteal bone was observed with no significant macroscopic or microscopic observations. Fractured sheep tibiae exhibited increased bone formation inside the osteotomy gap, with no significant difference when fixation was augmented by PBSS implants. Periosteal callus size gradually decreased over time and was similar in both treatment groups. No inhibition of endosteal bone remodeling or vascularization was observed with PBSS implants. Intramedullary application of a light-curable PBSS is a biocompatible, feasible method for fracture fixation.

  15. Segmentation of nanotomographic cortical bone images for quantitative characterization of the osteoctyte lacuno-canalicular network

    Energy Technology Data Exchange (ETDEWEB)

    Ciani, A.; Kewish, C. M. [Synchrotron Soleil, L’Orme des Merisiers, 91192 Saint-Aubin (France); Guizar-Sicairos, M.; Diaz, A.; Holler, M. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Pallu, S.; Achiou, Z.; Jennane, R.; Toumi, H.; Lespessailles, E. [Univ Orléans, I3MTO, Ea 4708, 45000 Orléans (France)

    2016-01-28

    A newly developed data processing method able to characterize the osteocytes lacuno-canalicular network (LCN) is presented. Osteocytes are the most abundant cells in the bone, living in spaces called lacunae embedded inside the bone matrix and connected to each other with an extensive network of canals that allows for the exchange of nutrients and for mechanotransduction functions. The geometrical three-dimensional (3D) architecture is increasingly thought to be related to the macroscopic strength or failure of the bone and it is becoming the focus for investigating widely spread diseases such as osteoporosis. To obtain 3D LCN images non-destructively has been out of reach until recently, since tens-of-nanometers scale resolution is required. Ptychographic tomography was validated for bone imaging in [1], showing clearly the LCN. The method presented here was applied to 3D ptychographic tomographic images in order to extract morphological and geometrical parameters of the lacuno-canalicular structures.

  16. Cortical bone growth and maturational changes in dwarf rats induced by recombinant human growth hormone

    Science.gov (United States)

    Martinez, D. A.; Orth, M. W.; Carr, K. E.; Vanderby, R. Jr; Vailas, A. C.

    1996-01-01

    The growth hormone (GH)-deficient dwarf rat was used to investigate recombinant human (rh) GH-induced bone formation and to determine whether rhGH facilitates simultaneous increases in bone formation and bone maturation during rapid growth. Twenty dwarf rats, 37 days of age, were randomly assigned to dwarf plus rhGH (GH; n = 10) and dwarf plus vehicle (n = 10) groups. The GH group received 1.25 mg rhGH/kg body wt two times daily for 14 days. Biochemical, morphological, and X-ray diffraction measurements were performed on the femur middiaphysis. rhGH stimulated new bone growth in the GH group, as demonstrated by significant increases (P growth.

  17. Optimization of process parameters for drilled hole quality characteristics during cortical bone drilling using Taguchi method.

    Science.gov (United States)

    Singh, Gurmeet; Jain, Vivek; Gupta, Dheeraj; Ghai, Aman

    2016-09-01

    Orthopaedic surgery involves drilling of bones to get them fixed at their original position. The drilling process used in orthopaedic surgery is most likely to the mechanical drilling process and there is all likelihood that it may harm the already damaged bone, the surrounding bone tissue and nerves, and the peril is not limited at that. It is very much feared that the recovery of that part may be impeded so that it may not be able to sustain life long. To achieve sustainable orthopaedic surgery, a surgeon must try to control the drilling damage at the time of bone drilling. The area around the holes decides the life of bone joint and so, the contiguous area of drilled hole must be intact and retain its properties even after drilling. This study mainly focuses on optimization of drilling parameters like rotational speed, feed rate and the type of tool at three levels each used by Taguchi optimization for surface roughness and material removal rate. The confirmation experiments were also carried out and results found with the confidence interval. Scanning electrode microscopy (SEM) images assisted in getting the micro level information of bone damage.

  18. Early cellular responses in cortical bone healing around unloaded titanium implants: an animal study.

    Science.gov (United States)

    Slaets, Elke; Carmeliet, Geert; Naert, Ignace; Duyck, Joke

    2006-06-01

    A clear understanding of the early cellular events leading to osseointegration of implants is currently lacking. To gain better insight, titanium implants were inserted in a rabbit model and histologic and histomorphometric analyses were performed at early time points after insertion. Thirty-six cylindrical implants were inserted in the tibial diaphysis of six rabbits and left to heal for 1 to 42 days. Samples were processed into paraffin or methylmethacrylate sections, on which the surface of new bone, region of altered nuclear morphology, relative surface of basic multicellular units (BMUs) and blood vessels, and bone-to-implant contact were measured. After coagulum formation, osteoclasts and osteoblasts were observed at the bone surface 1 week after healing. In the preexisting bone, osteocytic lacunae appeared to be devoid of cells. This region of altered nuclear morphology continued to extend for 28 days (P osteocytes surrounding the implantation site, intensive bone remodeling, and the formation of new bone, eventually leading to the osseointegration of the implant.

  19. Understanding site-specific residual strain and architecture in bovine cortical bone.

    Science.gov (United States)

    Giri, Bijay; Tadano, Shigeru; Fujisaki, Kazuhiro; Todoh, Masahiro

    2008-11-14

    Living bone is considered as adaptive material to the mechanical functions, which continually undergoes change in its histological arrangement with respect to external prolonged loading. Such remodeling phenomena within bone depend on the degree of stimuli caused by the mechanical loading being experienced, and therefore, are specific to the sites. In the attempts of understanding strain adaptive phenomena within bones, different theoretical models have been proposed. Also, the existing literatures mostly follow the measurement of surface strains using strain gauges to experimentally quantify the strains experienced in the functional environment. In this work, we propose a novel idea of understanding site-specific functional adaptation to the prolonged load in bone on the basis of inherited residual strains and structural organization. We quantified the residual strains and amount of apatite crystals distribution, i.e., the degree of orientation, using X-ray diffraction procedures. The sites of naturally existing hole in bone, called foramen, are considered from bovine femur and metacarpal samples. Significant values of residual strains are found to exist in the specimens. Trends of residual strains noted in the specimens are mostly consistent with the degree of orientation of the crystallites. These features explain the response behavior of bone to the mechanical loading history near the foramen sites. Preferential orientation of crystals mapped around a femoral foramen specimen showed furnished tailored arrangement of the crystals around the hole. Effect of external loading at the femoral foramen site is also explained by the tensile loading experiment.

  20. Effects of Habitual Physical Activity and Fitness on Tibial Cortical Bone Mass, Structure and Mass Distribution in Pre-pubertal Boys and Girls: The Look Study.

    Science.gov (United States)

    Duckham, Rachel L; Rantalainen, Timo; Ducher, Gaele; Hill, Briony; Telford, Richard D; Telford, Rohan M; Daly, Robin M

    2016-07-01

    Targeted weight-bearing activities during the pre-pubertal years can improve cortical bone mass, structure and distribution, but less is known about the influence of habitual physical activity (PA) and fitness. This study examined the effects of contrasting habitual PA and fitness levels on cortical bone density, geometry and mass distribution in pre-pubertal children. Boys (n = 241) and girls (n = 245) aged 7-9 years had a pQCT scan to measure tibial mid-shaft total, cortical and medullary area, cortical thickness, density, polar strength strain index (SSIpolar) and the mass/density distribution through the bone cortex (radial distribution divided into endo-, mid- and pericortical regions) and around the centre of mass (polar distribution). Four contrasting PA and fitness groups (inactive-unfit, inactive-fit, active-unfit, active-fit) were generated based on daily step counts (pedometer, 7-days) and fitness levels (20-m shuttle test and vertical jump) for boys and girls separately. Active-fit boys had 7.3-7.7 % greater cortical area and thickness compared to inactive-unfit boys (P < 0.05), which was largely due to a 6.4-7.8 % (P < 0.05) greater cortical mass in the posterior-lateral, medial and posterior-medial 66 % tibial regions. Cortical area was not significantly different across PA-fitness categories in girls, but active-fit girls had 6.1 % (P < 0.05) greater SSIpolar compared to inactive-fit girls, which was likely due to their 6.7 % (P < 0.05) greater total bone area. There was also a small region-specific cortical mass benefit in the posterior-medial 66 % tibia cortex in active-fit girls. Higher levels of habitual PA-fitness were associated with small regional-specific gains in 66 % tibial cortical bone mass in pre-pubertal children, particularly boys.

  1. A new implementation of digital X-ray radiogrammetry and reference curves of four indices of cortical bone for healthy European adults

    DEFF Research Database (Denmark)

    Thodberg, Hans Henrik; Böttcher, Joachim; Lomholt, Jens

    2016-01-01

    . PURPOSE: The digital X-ray radiogrammetry (DXR) method has been shown to be efficient for diagnosis of osteoporosis and for assessment of progression of rheumatoid arthritis. The aim of this work is to present a new DXR implementation and reference curves of four indices of cortical bone and to compare...

  2. Finite element analysis of dental implant loading on atrophic and non-atrophic cancellous and cortical mandibular bone - a feasibility study

    NARCIS (Netherlands)

    Marcián, P.; Borák, L.; Valášek, J.; Kaiser, J.; Florian, Z.; Wolff, J.

    2014-01-01

    The first aim of this study was to assess displacements and micro-strain induced on different grades of atrophic cortical and trabecular mandibular bone by axially loaded dental implants using finite element analysis (FEA). The second aim was to assess the micro-strain induced by different implant g

  3. Investigation of the effect of movement and irrigation systems on temperature in the conventional drilling of cortical bone.

    Science.gov (United States)

    Gehrke, Sergio Alexandre; Loffredo Neto, Henrique; Mardegan, Fábio E C

    2013-12-01

    We have compared the results of the external irrigation technique with those of a double irrigation technique with continuous intermittent movement. Maximum thermal measurements were made in the cortical part of 10 samples of bovine ribs during osteotomy to simulate the preparation of a surgical bed for the installation of dental implants at a depth of 10 mm. Twenty specimens were drilled for each group: external irrigation and continuous movement (control group 1, CG1); external irrigation and intermittent movement (control group 2, CG2); double irrigation and continuous movement (test group 1, TG1); and double irrigation and intermittent movement (test group 2, TG2). The double irrigation technique gave significantly better results regardless of the drilling movement used. Thermal increases between samples was 19.2% in group CG1, 10.4% in CG2, 5.4% in TG1, and 3.4% in TG2. The double irrigation technique produced a significantly smaller increase in temperature in the cortical bone during both types of drilling (p=0.001), which illustrated its greater efficiency compared with that of the external irrigation technique.

  4. Short-term and long-term site-specific effects of tennis playing on trabecular and cortical bone at the distal radius.

    Science.gov (United States)

    Ducher, Gaële; Tournaire, Nicolas; Meddahi-Pellé, Anne; Benhamou, Claude-Laurent; Courteix, Daniel

    2006-01-01

    Mechanical loading during growth magnifies the normal increase in bone diameter occurring in long bone shafts, but the response to loading in long bone ends remains unclear. The aim of the study was to investigate the effects of tennis playing during growth at the distal radius, comparing the bone response at trabecular and cortical skeletal sites. The influence of training duration was examined by studying bone response in short-term (children) and long-term (young adults) perspectives. Bone area, bone mineral content (BMC), and bone mineral density (BMD) of the radius were measured by DXA in 28 young (11.6 +/- 1.4 years old) and 47 adult tennis players (22.3 +/- 2.7 years old), and 70 age-matched controls (12 children, 58 adults) at three sites: the ultradistal region (trabecular), the mid-distal region, and the third-distal region (cortical). At the ultradistal radius, young and adult tennis players displayed similar side-to-side differences, the asymmetry in BMC reaching 16.3% and 13.8%, respectively (P < 0.0001). At the mid- and third-distal radius, the asymmetry was much greater in adults than in children (P < 0.0001) for all the bone parameters (mid-distal radius, +6.6% versus +15.6%; third-distal radius, +6.9% versus +13.3%, for BMC). Epiphyseal bone enduring longitudinal growth showed a great capacity to respond to mechanical loading in children. Prolonging tennis playing into adulthood was associated with further increase in bone mineralization at diaphyseal skeletal sites. These findings illustrate the benefits of practicing impact-loading sports during growth and maintaining physical activity into adulthood to enhance bone mass accrual and prevent fractures later in life.

  5. Evaluation of tibolone administration in bone architectural by MicroCT

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, A. C. B.; Henriques, H. N. [Patology Dept., Fluminense Federal Univ., Niteroi (Brazil); Granjeiro, J. M. [Molecular and Cell Biology Dept., Fluminense Federal Univ., Niteroi, Rio de Janeiro (Brazil); Guzman-Silva, M. A. [Patology Dept., Fluminense Federal Univ., Niteroi (Brazil); Lopes, R. T.; Lima, I. [Nuclear Engineering Laboratory, Federal Univ. of Rio de Janeiro (Brazil)

    2011-07-01

    Elderly women are at higher risk for hip fracture because of additional and relatively rapid bone loss due to estrogen deficiency by loss of the ovarian function and a longer average life span than men. The early application of agents that suppress the increase in bone turnover due to estrogen deficiency is essential to prevent bone loss and reduce the risk of osteoporosis. Some advanced imaging techniques may be required to investigate osteoporosis. X-ray micro-computed tomography has been used to generate high-resolution 3D images of cancellous and cortical bone morphology from normal and pathologic human and animal specimens. The aim of this study is to verify the effects of tibolone administration by evaluating the trabecular bone region. The experiment was performed on two groups of rats previously ovariectomized in which one received tibolone while the other did not. Tibolone administration (1 mg/day) began thirty days after the ovariectomy and the treatment remained for five months. At last, the animals were euthanized and femurs were collected. The scan was obtained using a Hamamatsu 10 Mp camera with a pixel size of 11.59 {mu}m and trabecular region in the right femoral head were quantified. All results were statistically evaluated with significance set at P<0.05%. Tibolone administration was shown to be beneficial in some analysis of the femoral head, performing higher bone volume and reducing the porosity when compared to ovariectomized. It can be concluded that tibolone administered to ovariectomized rats significantly preserved bone mass in the femoral head and microtomography was an efficient method to identify bone loss process and to evaluate potential therapies, as tibolone administration. (authors)

  6. Ratio between mature and immature enzymatic cross-links correlates with post-yield cortical bone behavior: An insight into greenstick fractures of the child fibula.

    Science.gov (United States)

    Berteau, Jean-Philippe; Gineyts, Evelyne; Pithioux, Martine; Baron, Cécile; Boivin, Georges; Lasaygues, Philippe; Chabrand, Patrick; Follet, Hélène

    2015-10-01

    As a determinant of skeletal fragility, the organic matrix is responsible for the post-yield and creep behavior of bone and for its toughness, while the mineral apatite acts on stiffness. Specific to the fibula and ulna in children, greenstick fractures show a plastic in vivo mechanical behavior before bone fracture. During growth, the immature form of collagen enzymatic cross-links gradually decreases, to be replaced by the mature form until adolescence, subsequently remaining constant throughout adult life. However, the link between the cortical bone organic matrix and greenstick fractures in children remains to be explored. Here, we sought to determine: 1) whether plastic bending fractures can occur in vitro, by testing cortical bone samples from children's fibula and 2) whether the post-yield behavior (ωp plastic energy) of cortical bone before fracture is related to total quantity of the collagen matrix, or to the quantity of mature and immature enzymatic cross-links and the quantity of non-enzymatic cross-links. We used a two-step approach; first, a 3-point microbending device tested 22 fibula machined bone samples from 7 children and 3 elderly adults until fracture. Second, biochemical analysis by HPLC was performed on the sample fragments. When pooling two groups of donors, children and elderly adults, results show a rank correlation between total energy dissipated before fracture and age and a linear correlation between plastic energy dissipated before fracture and ratio of immature/mature cross-links. A collagen matrix with more immature cross-links (i.e. a higher immature/mature cross-link ratio) is more likely to plastically deform before fracture. We conclude that this ratio in the sub-nanostructure of the organic matrix in cortical bone from the fibula may go some way towards explaining the variance in post-yield behavior. From a clinical point of view, therefore, our results provide a potential explanation of the presence of greenstick fractures in

  7. Evaluation of the bone healing process in an experimental tibial bone defect model in ovariectomized rats.

    Science.gov (United States)

    Kido, Hueliton Wilian; Bossini, Paulo Sérgio; Tim, Carla Roberta; Parizotto, Nivaldo Antônio; da Cunha, Anderson Ferreira; Malavazi, Iran; Renno, Ana Claudia Muniz

    2014-10-01

    The aim of this study was to evaluate the influence of postmenopausal bone loss (induced by ovariectomy) in the process of bone healing in a tibial bone defect model in rats by means of histological evaluation of bone defects and the analysis of the expression of genes and proteins involved in bone consolidation. Twenty female Wistar rats (12 weeks old, weighing ±250 g) were randomly divided into two groups: control group (CG) and ovariectomized group (OG). Rats of OG were submitted to ovariectomy and after 8 weeks post-surgery, all animals were submitted to the tibial bone defect model. The main histological finding analysis revealed that ovariectomized animals showed a higher amount of granulation tissue and immature newly formed bone compared to CG. Furthermore, quantitative histological analysis showed that OG presented a significant decrease in the amount of newly formed bone (p = 0.0351). RT-PCR analysis showed no difference in Runx2, ALP, RANK, RANKL and Osterix gene expression 14-day post-surgery. Interestingly, immunohistochemical evaluation showed that Runx2 was down expressed (p = 0.0001) and RANKL was up expressed (p = 0.0022) in the OG. In conclusion, these data highlight that bone loss induced by ovariectomy causes an impairment in the capacity of bone to heal mainly probably because of alterations in the imbalance of osteoblasts and osteoclasts activities.

  8. Mecânica e microbiologia de placas produzidas a partir de osso cortical bovino, conservadas em diferentes meios Mechanic and microbiology of plates produced from bovine cortical bone, conserved in several means

    Directory of Open Access Journals (Sweden)

    Edson Vilela de Melo Filho

    2011-04-01

    Full Text Available Objetivou-se com este trabalho avaliar a resistência mecânica de placas ósseas produzidas a partir de osso cortical bovino, conservadas em diferentes meios, e a eficiência desses meios em inibir o crescimento de microrganismos. Foram utilizadas 168 placas confeccionadas a partir de tíbia bovina e conservadas em glicerina a 98%, solução salina a 150%, solução de açúcar a 300%, líquido de Dakin, congeladas em N2L a -196°C, ou esterilizadas em óxido de etileno. Após reidratação em solução de cloreto de sódio a 0,9% por seis horas, elas foram submetidas a ensaios mecânicos de tração, compressão, flexão e torção. Foi realizada avaliação microbiológica das placas anterior e imediatamente após a reidratação, com ou sem adição de enrofloxacina a 0,5%. Não se observou diferença significativa (PThe objective of this study was to evaluate the mechanical strength of bone plates yielded from bovine cortical bone, conserved in different solutions, and the efficiency of these solutions in the inhibition of microorganism's growth. A hundred and sixty eight plates yielded from bovine tibiae were conserved in 98% glycerin, 150% saline solution, 300% sugar solution, Dakin solution, frozen in N2L at - 196°C, or sterilized in ethylene oxide gas. After rehydration in NaCl 0.9% solution for six hours, plates were subjected to tensile, compression, bending and twisting testing. The microbiological evaluation of bone plates was s carried out before and immediately after rehydration, with or without enrofloxacin 0.5% addition. There was no significant difference (P<0.01% on resistance to the rupture point in plates conserved in different solutions, frozen-thawed or sterilized. Microorganisms were isolated from plates conserved in satured salt solution, sugar satured solution, Dakin solution or frozen in N2L, before and after rehydraion However, after the use of NaCl 0.9% solution added of enrofloxacin 0.5%, microorganisms were not

  9. Evaluation of different rotary devices on bone repair in rabbits

    OpenAIRE

    Ribeiro Junior, Paulo Domingos; Barleto, Christiane Vespasiano; Ribeiro,Daniel Araki; Matsumoto,Mariza Akemi

    2007-01-01

    In oral surgery, the quality of bone repair may be influenced by several factors that can increase the morbidity of the procedure. The type of equipment used for ostectomy can directly affect bone healing. The aim of this study was to evaluate bone repair of mandible bone defects prepared in rabbits using three different rotary devices. Fifteen New Zealand rabbits were randomly assigned to 3 groups (n=5) according to type of rotary device used to create bone defects: I - pneumatic low-speed r...

  10. Scanning transmission electron microscopic tomography of cortical bone using Z-contrast imaging.

    Science.gov (United States)

    McNally, Elizabeth; Nan, Feihong; Botton, Gianluigi A; Schwarcz, Henry P

    2013-06-01

    Previously we presented (McNally et al., 2012) a model for the ultrastructure of bone showing that the mineral resides principally outside collagen fibrils in the form of 5 nm thick mineral structures hundreds of nanometers long oriented parallel to the fibrils. Here we use high-angle annular dark-field electron tomography in the scanning transmission electron microscope to confirm this model and further elucidate the composite structure. Views of a section cut parallel to the fibril axes show bundles of mineral structures extending parallel to the fibrils and encircling them. The mineral density inside the fibrils is too low to be visualized in these tomographic images. A section cut perpendicular to the fibril axes, shows quasi-circular walls composed of mineral structures, wrapping around apparently empty holes marking the sites of fibrils. These images confirm our original model that the majority of mineral in bone resides outside the collagen fibrils.

  11. Small body size and extreme cortical bone remodeling indicate phyletic dwarfism in Magyarosaurus dacus (Sauropoda: Titanosauria).

    Science.gov (United States)

    Stein, Koen; Csiki, Zoltan; Rogers, Kristina Curry; Weishampel, David B; Redelstorff, Ragna; Carballido, Jose L; Sander, P Martin

    2010-05-18

    Sauropods were the largest terrestrial tetrapods (>10(5) kg) in Earth's history and grew at rates that rival those of extant mammals. Magyarosaurus dacus, a titanosaurian sauropod from the Upper Cretaceous (Maastrichtian) of Romania, is known exclusively from small individuals (dwarfism (phyletic nanism) in dinosaurs, but a recent study suggested that the small Romanian titanosaurs actually represent juveniles of a larger-bodied taxon. Here we present strong histological evidence that M. dacus was indeed a dwarf (phyletic nanoid). Bone histological analysis of an ontogenetic series of Magyarosaurus limb bones indicates that even the smallest Magyarosaurus specimens exhibit a bone microstructure identical to fully mature or old individuals of other sauropod taxa. Comparison of histologies with large-bodied sauropods suggests that Magyarosaurus had an extremely reduced growth rate, but had retained high basal metabolic rates typical for sauropods. The uniquely decreased growth rate and diminutive body size in Magyarosaurus were adaptations to life on a Cretaceous island and show that sauropod dinosaurs were not exempt from general ecological principles limiting body size.

  12. A novel underuse model shows that inactivity but not ovariectomy determines the deteriorated material properties and geometry of cortical bone in the tibia of adult rats.

    Science.gov (United States)

    Miyagawa, Kazuaki; Kozai, Yusuke; Ito, Yumi; Furuhama, Takami; Naruse, Kouji; Nonaka, Kiichi; Nagai, Yumiko; Yamato, Hideyuki; Kashima, Isamu; Ohya, Keiichi; Aoki, Kazuhiro; Mikuni-Takagaki, Yuko

    2011-07-01

    Our goal in this study was to determine to what extent the physiologic consequences of ovariectomy (OVX) in bones are exacerbated by a lack of daily activity such as walking. We forced 14-week-old female rats to be inactive for 15 weeks with a unique experimental system that prevents standing and walking while allowing other movements. Tibiae, femora, and 4th lumbar vertebrae were analyzed by peripheral quantitative computed tomography (pQCT), microfocused X-ray computed tomography (micro-CT), histology, histomorphometry, Raman spectroscopy, and the three-point bending test. Contrary to our expectation, the exacerbation was very much limited to the cancellous bone parameters. Parameters of femur and tibia cortical bone were affected by the forced inactivity but not by OVX: (1) cross-sectional moment of inertia was significantly smaller in Sham-Inactive rat bones than that of their walking counterparts; (2) the number of sclerostin-positive osteocytes per unit cross-sectional area was larger in Sham-Inactive rat bones than in Sham-Walking rat bones; and (3) material properties such as ultimate stress of inactive rat tibia was lower than that of their walking counterparts. Of note, the additive effect of inactivity and OVX was seen only in a few parameters, such as the cancellous bone mineral density of the lumbar vertebrae and the structural parameters of cancellous bone in the lumbar vertebrae/tibiae. It is concluded that the lack of daily activity is detrimental to the strength and quality of cortical bone in the femur and tibia of rats, while lack of estrogen is not. Our inactive rat model, with the older rats, will aid the study of postmenopausal osteoporosis, the etiology of which may be both hormonal and mechanical.

  13. Evaluating interhemispheric cortical responses to transcranial magnetic stimulation in chronic stroke: A TMS-EEG investigation.

    Science.gov (United States)

    Borich, Michael R; Wheaton, Lewis A; Brodie, Sonia M; Lakhani, Bimal; Boyd, Lara A

    2016-04-01

    TMS-evoked cortical responses can be measured using simultaneous electroencephalography (TMS-EEG) to directly quantify cortical connectivity in the human brain. The purpose of this study was to evaluate interhemispheric cortical connectivity between the primary motor cortices (M1s) in participants with chronic stroke and controls using TMS-EEG. Ten participants with chronic stroke and four controls were tested. TMS-evoked responses were recorded at rest and during a typical TMS assessment of transcallosal inhibition (TCI). EEG recordings from peri-central gyral electrodes (C3 and C4) were evaluated using imaginary phase coherence (IPC) analyses to quantify levels of effective interhemispheric connectivity. Significantly increased TMS-evoked beta (15-30Hz frequency range) IPC was observed in the stroke group during ipsilesional M1 stimulation compared to controls during TCI assessment but not at rest. TMS-evoked beta IPC values were associated with TMS measures of transcallosal inhibition across groups. These results suggest TMS-evoked EEG responses can index abnormal effective interhemispheric connectivity in chronic stroke.

  14. Microradiography to evaluate bone growth into a rat mandibular defect

    NARCIS (Netherlands)

    Schortinghuis, J; Ruben, JL; Meijer, HJA; Bronckers, ALJJ; Raghoebar, GM; Stegenga, B; Schortinghuisa, Jurjen; Rubenb, Jan L.; Meijera, Henny J.A.; Bronckersc, Antonius L.J.J.; Raghoebara, Gerry M.

    Microradiography has been evaluated to measure bone heating into a 5.0 mm outer diameter mandibular defect in the rat. This method provides high-resolution radiographs of the defects that can be used for an accurate measurement of bone defect heating. In 12 rats, the defect widths of 42-day-old

  15. Estimation of femoral bone density from trabecular direct wave and cortical guided wave ultrasound velocities measured at the proximal femur in vivo

    DEFF Research Database (Denmark)

    Barkmann, Reinhard; Dencks, Stefanie; Bremer, Alexander

    2008-01-01

    Bone mineral density (BMD) of the proximal femur is a predictor of hip fracture risk. We developed a Quantitative Ultrasound (QUS) scanner for measurements at this site with similar performance (FemUS). In this study we tested if ultrasound velocities of direct waves through trabecular bone...... echoes reflected from the skin of the leg to yield speed-of-sound (SOS) of different wave components. Data were cross-calibrated and pooled (62 women). Bivariate correlations and a multivariate model were calculated for the estimation of femur BMD. BMD correlated both with trabecular and cortical SOS...

  16. Evaluation of the motor cortical excitability changes after ischemic stroke

    Directory of Open Access Journals (Sweden)

    D K Prashantha

    2013-01-01

    Full Text Available Background: We evaluated progressive changes in excitability of motor cortex following ischemic stroke using Transcranial Magnetic Stimulation (TMS. Materials and Methods: Thirty-one patients (24 men, 7 women; age 37.3 ± 8.2 years were recruited and TMS was performed using Magstim 200 stimulator and a figure-of-eight coil. Resting motor threshold (RMT was recorded from affected and unaffected hemispheres and motor evoked potential (MEP was recorded from contralateral FDI muscle. Central motor conduction time (CMCT was calculated using F wave method. All measurements were done at baseline (2 nd , 4 th , and 6 th week of stroke. Results: Affected hemisphere: MEP was recordable in 3 patients at baseline (all had prolonged CMCT. At 4 weeks, MEP was recordable in one additional patient and CMCT remained prolonged. At 6 weeks, CMCT normalized in one patient. RMT was recordable (increased in 3 patients at baseline, in one additional patient at 4 weeks, and reduced marginally in these patients at 6 weeks. Unaffected hemisphere: MEP was recordable in all patients at baseline, and reduced significantly over time (2 nd week 43.52 ± 9.60, 4 th week 38.84 ± 7.83, and 6 th week 36.85 ± 7.27; P < 0.001. The CMCT was normal and remained unchanged over time. Conclusion: The increase in excitability of the unaffected motor cortex suggests plasticity in the post-stroke phase.

  17. Evaluation of the Cortical Silent Period of the Laryngeal Motor Cortex in Healthy Individuals

    Science.gov (United States)

    Chen, Mo; Summers, Rebekah L. S.; Goding, George S.; Samargia, Sharyl; Ludlow, Christy L.; Prudente, Cecília N.; Kimberley, Teresa J.

    2017-01-01

    Objective: This work aimed to evaluate the cortical silent period (cSP) of the laryngeal motor cortex (LMC) using the bilateral thyroarytenoid (TA) muscles with transcranial magnetic stimulation (TMS). Methods: In 11 healthy participants, fine-wire electromyography (EMG) was used to record bilateral TA muscle responses to single pulse TMS delivered to the LMC in both hemispheres. Peripheral responses to stimulation over the mastoid, where the vagus nerve exits the skull, were collected to verify the central origin of the cortical stimulation responses by comparing the latencies. Results: The cSP duration ranged from 41.7 to 66.4 ms. The peripherally evoked motor-evoked potential (MEP) peak occurred 5–9 ms earlier than the cortical responses (for both sides of TAs: p < 0.0001) with no silent period. The right TA MEP latencies were earlier than the left TA responses for both peripheral and cortical measures (p ≤ 0.0001). Conclusion: These findings demonstrate the feasibility of measuring cSP of LMC based on intrinsic laryngeal muscles responses during vocalization in healthy volunteers. Significance: The technique could be used to study the pathophysiology of neurological disorders that affect TA muscles, such as spasmodic dysphonia. Further, the methodology has application to other muscles of the head and neck not accessible using surface electrodes. PMID:28326007

  18. Effect of accelerated electron beam on mechanical properties of human cortical bone: influence of different processing methods.

    Science.gov (United States)

    Kaminski, Artur; Grazka, Ewelina; Jastrzebska, Anna; Marowska, Joanna; Gut, Grzegorz; Wojciechowski, Artur; Uhrynowska-Tyszkiewicz, Izabela

    2012-08-01

    Accelerated electron beam (EB) irradiation has been a sufficient method used for sterilisation of human tissue grafts for many years in a number of tissue banks. Accelerated EB, in contrast to more often used gamma photons, is a form of ionizing radiation that is characterized by lower penetration, however it is more effective in producing ionisation and to reach the same level of sterility, the exposition time of irradiated product is shorter. There are several factors, including dose and temperature of irradiation, processing conditions, as well as source of irradiation that may influence mechanical properties of a bone graft. The purpose of this study was to evaluate the effect e-beam irradiation with doses of 25 or 35 kGy, performed on dry ice or at ambient temperature, on mechanical properties of non-defatted or defatted compact bone grafts. Left and right femurs from six male cadaveric donors, aged from 46 to 54 years, were transversely cut into slices of 10 mm height, parallel to the longitudinal axis of the bone. Compact bone rings were assigned to the eight experimental groups according to the different processing method (defatted or non-defatted), as well as e-beam irradiation dose (25 or 35 kGy) and temperature conditions of irradiation (ambient temperature or dry ice). Axial compression testing was performed with a material testing machine. Results obtained for elastic and plastic regions of stress-strain curves examined by univariate analysis are described. Based on multivariate analysis, including all groups, it was found that temperature of e-beam irradiation and defatting had no consistent significant effect on evaluated mechanical parameters of compact bone rings. In contrast, irradiation with both doses significantly decreased the ultimate strain and its derivative toughness, while not affecting the ultimate stress (bone strength). As no deterioration of mechanical properties was observed in the elastic region, the reduction of the energy

  19. Computer modelling integrated with micro-CT and material testing provides additional insight to evaluate bone treatments: Application to a beta-glycan derived whey protein mice model.

    Science.gov (United States)

    Sreenivasan, D; Tu, P T; Dickinson, M; Watson, M; Blais, A; Das, R; Cornish, J; Fernandez, J

    2016-01-01

    The primary aim of this study was to evaluate the influence of a whey protein diet on computationally predicted mechanical strength of murine bones in both trabecular and cortical regions of the femur. There was no significant influence on mechanical strength in cortical bone observed with increasing whey protein treatment, consistent with cortical tissue mineral density (TMD) and bone volume changes observed. Trabecular bone showed a significant decline in strength with increasing whey protein treatment when nanoindentation derived Young׳s moduli were used in the model. When microindentation, micro-CT phantom density or normalised Young׳s moduli were included in the model a non-significant decline in strength was exhibited. These results for trabecular bone were consistent with both trabecular bone mineral density (BMD) and micro-CT indices obtained independently. The secondary aim of this study was to characterise the influence of different sources of Young׳s moduli on computational prediction. This study aimed to quantify the predicted mechanical strength in 3D from these sources and evaluate if trends and conclusions remained consistent. For cortical bone, predicted mechanical strength behaviour was consistent across all sources of Young׳s moduli. There was no difference in treatment trend observed when Young׳s moduli were normalised. In contrast, trabecular strength due to whey protein treatment significantly reduced when material properties from nanoindentation were introduced. Other material property sources were not significant but emphasised the strength trend over normalised material properties. This shows strength at the trabecular level was attributed to both changes in bone architecture and material properties.

  20. Histomorphometric evaluation of bone regeneration using autogenous bone and beta-tricalcium phosphate in diabetic rabbits

    Directory of Open Access Journals (Sweden)

    Živadinović Milka

    2016-01-01

    Full Text Available Background/Aim. The mechanism of impaired bone healing in diabetes mellitus includes different tissue and cellular level activities due to micro- and macrovascular changes. As a chronic metabolic disease with vascular complications, diabetes affects a process of bone regeneration as well. The therapeutic approach in bone regeneration is based on the use of osteoinductive autogenous grafts as well as osteoconductive synthetic material, like a β-tricalcium phosphate. The aim of the study was to determine the quality and quantity of new bone formation after the use of autogenous bone and β-tricalcium phosphate in the model of calvarial critical-sized defect in rabbits with induced diabetes mellitus type I. Methods. The study included eight 4-month-old Chincilla rabbits with alloxan-induced diabetes mellitus type I. In all animals, there were surgically created two calvarial bilateral defects (diameter 12 mm, which were grafted with autogenous bone and β-tricalcium phosphate (n = 4 or served as unfilled controls (n = 4. After 4 weeks of healing, animals were sacrificed and calvarial bone blocks were taken for histologic and histomorphometric analysis. Beside descriptive histologic evaluation, the percentage of new bone formation, connective tissue and residual graft were calculated. All parameters were statistically evaluated by Friedman Test and post hock Wilcoxon Singed Ranks Test with a significance of p < 0.05. Results. Histology revealed active new bone formation peripherally with centrally located connective tissue, newly formed woven bone and well incorporated residual grafts in all treated defects. Control samples showed no bone bridging of defects. There was a significantly more new bone in autogeonous graft (53% compared with β-tricalcium phosphate (30%, (p < 0.030 and control (7%, (p < 0.000 groups. A significant difference was also recorded between β-tricalcium phosphate and control groups (p < 0.008. Conclusion. In the present

  1. The effect of excitation and preparation pulses on nonslice selective 2D UTE bicomponent analysis of bound and free water in cortical bone at 3T

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shihong [Department of Radiology, University of California, San Diego, California 92103-8226 (United States); Department of Radiology, Hua Dong Hospital, Fudan University, Shanghai 200040 (China); Yancheng Medical College, Jiangsu (China); The First People' s Hospital of Yancheng City, Jiangsu 224005 (China); Chang, Eric Y.; Chung, Christine B. [VA San Diego Healthcare System, San Diego, California 92161 and Department of Radiology, University of California, San Diego, California 92103-8226 (United States); Bae, Won C.; Du, Jiang, E-mail: jiangdu@ucsd.edu [Department of Radiology, University of California, San Diego, California 92103-8226 (United States); Hua, Yanqing [Department of Radiology, Hua Dong Hospital, Fudan University, Shanghai 200040 (China); Zhou, Yi [The First People' s Hospital of Yancheng City, Jiangsu 224005 (China)

    2014-02-15

    Purpose: The purpose of this study was to investigate the effect of excitation, fat saturation, long T2 saturation, and adiabatic inversion pulses on ultrashort echo time (UTE) imaging with bicomponent analysis of bound and free water in cortical bone for potential applications in osteoporosis. Methods: Six bovine cortical bones and six human tibial midshaft samples were harvested for this study. Each bone sample was imaged with eight sequences using 2D UTE imaging at 3T with half and hard excitation pulses, without and with fat saturation, long T2 saturation, and adiabatic inversion recovery (IR) preparation pulses. Single- and bicomponent signal models were utilized to calculate the T2{sup *}s and/or relative fractions of short and long T2{sup *}s. Results: For all bone samples UTE T2{sup *} signal decay showed bicomponent behavior. A higher short T2{sup *} fraction was observed on UTE images with hard pulse excitation compared with half pulse excitation (75.6% vs 68.8% in bovine bone, 79.9% vs 73.2% in human bone). Fat saturation pulses slightly reduced the short T2{sup *} fraction relative to regular UTE sequences (5.0% and 2.0% reduction, respectively, with half and hard excitation pulses for bovine bone, 6.3% and 8.2% reduction, respectively, with half and hard excitation pulses for human bone). Long T2 saturation pulses significantly reduced the long T2{sup *} fraction relative to regular UTE sequence (18.9% and 17.2% reduction, respectively, with half and hard excitation pulses for bovine bone, 26.4% and 27.7% reduction, respectively, with half and hard excitation pulses for human bone). With IR-UTE preparation the long T2{sup *} components were significantly reduced relative to regular UTE sequence (75.3% and 66.4% reduction, respectively, with half and hard excitation pulses for bovine bone, 87.7% and 90.3% reduction, respectively, with half and hard excitation pulses for human bone). Conclusions: Bound and free water T2{sup *}s and relative fractions can

  2. Effect of ovariectomy on BMD, micro-architecture and biomechanics of cortical and cancellous bones in a sheep model.

    Science.gov (United States)

    Wu, Zi-xiang; Lei, Wei; Hu, Yun-yu; Wang, Hai-qiang; Wan, Shi-yong; Ma, Zhen-sheng; Sang, Hong-xun; Fu, Suo-chao; Han, Yi-sheng

    2008-11-01

    Osteoporotic/osteopenia fractures occur most frequently in trabeculae-rich skeletal sites. The purpose of this study was to use a high-resolution micro-computed tomography (micro-CT) and dual energy X-ray absorptionmeter (DEXA) to investigate the changes in micro-architecture and bone mineral density (BMD) in a sheep model resulted from ovariectomy (OVX). Biomechanical tests were performed to evaluate the strength of the trabecular bone. Twenty adult sheeps were randomly divided into three groups: sham group (n=8), group 1 (n=4) and group 2 (n=8). In groups 1 and 2, all sheep were ovariectomized (OVX); in the sham group, the ovaries were located and the oviducts were ligated. In all animals, BMD for lumbar spine was obtained during the surgical procedure. BMD at the spine, femoral neck and femoral condyle was determined 6 months (group 1) and 12 months (group 2) post-OVX. Lumbar spines and femora were obtained and underwent BMD scan, micro-CT analysis. Compressive mechanical properties were determined from biopsies of vertebral bodies and femoral condyles. BMD, micro-architectural parameters and mechanical properties of cancellous bone did not decrease significantly at 6 months post-OVX. Twelve months after OVX, BMD, micro-architectural parameters and mechanical properties decreased significantly. The results of linear regression analyses showed that trabecular thickness (Tb.Th) (r=0.945, R2=0.886) and bone volume fraction (BV/TV) (r=0.783, R2=0.586) had strong (R2>0.5) correlation to compression stress. In OVX sheep, changes in the structural parameters of trabecular bone are comparable to the human situation during osteoporosis was induced. The sheep model presented seems to meet the criteria for an osteopenia model for fracture treatment with respect to morphometric and mechanical properties. But the duration of OVX must be longer than 12 months to ensure the animal model can be established successfully.

  3. Fetal and neonatal exposure to the endocrine disruptor, methoxychlor, reduces lean body mass and bone mineral density and increases cortical porosity.

    Science.gov (United States)

    Fagnant, Heather S; Uzumcu, Mehmet; Buckendahl, Patricia; Dunn, Michael G; Shupper, Peter; Shapses, Sue A

    2014-12-01

    Endogenous estrogen has beneficial effects on mature bone and negatively affects the developing skeleton, whereas the effect of environmental estrogens is not known. Methoxychlor (MXC) is a synthetic estrogen known as a persistent organochlorine and used as a pesticide. Methoxychlor and its metabolites display estrogenic, anti-estrogenic and anti-androgenic activity and may therefore influence bone. Fifty-eight male fetal and neonatal rats were exposed to either: a negative control (DMSO), 0.020, 100 mg/kg MXC, or 1 mg/kg β-estradiol-3-benzoate (EB; positive control). Rats were treated daily for 11 days, from embryonic day 19 to postnatal day (PND) 7 or for 4 days during the postnatal period (PND 0-7). All rats were analyzed at PND-84. Total body, femur, spine, and tibia areal bone mineral density (BMD) and content (BMC), lean body mass (LBM) and fat were measured by dual energy X-ray absorptiometry. Bone geometry and volumetric (v) BMD were measured using micro-computed tomography and biomechanical properties using three-point bending were assessed. Rats exposed to EB or MXC (at either the high and/or low dose), independent of exposure interval showed lower body weight, LBM, tibia and femur BMD and length, and total body BMD and BMC than DMSO control group (p ≤ 0.05). Methoxychlor and EB exposure increased cortical porosity compared to DMSO controls. Trabecular vBMD, number and separation, and cortical polar moment of inertia and cross-sectional area were lower due to EB exposure compared to control (p < 0.05). Early MXC exposure compromises cortical porosity and bone size at maturity, and could ultimately increase the risk of fracture with aging.

  4. Keel bone condition in laying hens: a histological evaluation of macroscopically assessed keel bones.

    Science.gov (United States)

    Scholz, Britta; Rönchen, Swaantje; Hamann, Henning; Hewicker-Trautwein, Marion; Distl, Ottmar

    2008-01-01

    The objective of the present study was to conduct a corresponding histological analysis of 162 macroscopically assessed keel bones (1: severe, 2: moderate, 3: slight, 4: no deformity). Four layer lines were used and hens were kept in furnished cages, small group systems (both allowing more activities due to the provision of perches) and an aviary system, which fully conformed to the EU standards. Investigations were carried out in the 3rd, 6th, 9th and 12th laying month of two experimental trials. In 97.9% of grade 4 keel bones, no histological deviations were found, whereas in keel bones manifesting deformities of grade 1 and 2, the predominant histological observation was the incidence of fracture callus material (FCM) and new bone in the form of woven bone. FCM was also detected in 50.9% of grade 3 keel bones, whereas in 40.7%, only s-shaped deviations of keel bones were found, which were related to extended pressure loading while perching activities rather than short-duration trauma. Histological analysis showed that keel bones of grade 1 and 2 were mainly attributed to traumatic origin and therefore associated with pain experience in layers. Grade 3 keel bones manifested either FCM as a result of trauma or adaptational deformities without any evidence of a preceding fracture in response to mechanical pressure loading and were most likely not associated with pain. Therefore, histological analysis was found to be a mandatory tool when evaluating grade 3 keel bones with respect to layers'welfare. Furthermore, this analysis corroborates the findings that in aviary systems deformities of keel bones are predominantly caused by painful fractures.

  5. Strength prediction of the distal radius by bone densitometry--evaluation using biomechanical tests.

    Science.gov (United States)

    Eckstein, Felix; Kuhn, Volker; Lochmüller, Eva-Maria

    2004-03-01

    Osteoporotic fractures represent an important medical problem as they are often early predictors of future fractures at other skeletal sites. The distal radius is one such fracture site. To determine the individual's risk of fracture, different measurement techniques have been developed. These methods differ in physical background, measurement site, output parameters, and cost. If correctly applied, biomechanical testing can be an efficient tool for the preclinical evaluation of these techniques. With biomechanical testing it is possible to determine the structural strength of bone which can then be correlated with various densitometric parameters. Here we will review experimental work performed in this context. Biomechanical testing conditions vary considerably from study to study with 3-point bending (shaft), axial compression (metaphysis), and fall simulations being some of the techniques used. Experimental evidence suggests that site-specific osteodensitometric measurements can predict the mechanical strength of the distal radius with moderate to high accuracy, but that measurements at remote sites display considerably lower predictive value. Geometry-based parameters of cortical bone are also good predictors, but have not been shown to offer significant advantage over measurement of bone mass. Some (but not all) studies have found that quantitative ultrasound and microstructural parameters contribute significant additional information to bone mass measurement. The most accurate prediction of distal radius fractures, however, appears to be (patient-specific) microstructural finite element modeling.

  6. Influence of PRF in the healing of bone and gingival tissues. Clinical and histological evaluations.

    Science.gov (United States)

    Marrelli, M; Tatullo, M

    2013-07-01

    The healing of bone tissues around dental implants is based primarily on a correct osseointegration. Typically, implants stability and peri-implant tissues health are anticipated to decrease during the early weeks of healing; this is followed by an increase in stability. The aim of the present study is to assess a predictable protocol in order to increase the peri-implant tissues maintenance around post-extractive dental implants, thanks to the use of Platelet-Rich Fibrin (PRF) membrane. This is a retrospective observational study of 127 tapered dental implants placed in the immediate post-extraction sites of maxillary bone of 59 patients. Atraumatic dental extraction and flapless implant surgery was performed in all reported cases. The cortical bone position relative to the implant reference point was evaluated at implant placement and 10 to 24 months following implantology. The gap between bone tissue and the implant surface was measured up to a maximum of 3 mm. After placing implants we have filled the surgical site with a PRF gel, so as to fill the gap between bone tissue and the implant surface, and then we have covered the surgical site with a PRF membrane, so as to coat the gap between the alveolar crest and the implant. In all cases, we observed the complete covering of the dental implants, with newly formed soft tissue of variable thickness between 1 and 3 mm. Cortical bone adaptation from the time of implant placement up to 30 months following prosthetic restoration ranged from 0.4 mm to 1.7 mm. Our study showed a series of successful rehabilitations, with post-extraction implantology technique, in 99.8 percent of cases, despite the success rates in the medium and long-term post-extraction implantology reported in the literature range between 92.7 percent and 98.0 percent. Long-term maintenance of crestal bone and the rapid healing of soft tissue dimension with maintenance of peri-implant papilla were observed as outcomes after post-extractive implants

  7. Quantifying the Effects of Formalin Fixation on the Mechanical Properties of Cortical Bone Using Beam Theory and Optimization Methodology With Specimen-Specific Finite Element Models.

    Science.gov (United States)

    Zhang, Guan-Jun; Yang, Jie; Guan, Feng-Jiao; Chen, Dan; Li, Na; Cao, Libo; Mao, Haojie

    2016-09-01

    The effects of formalin fixation on bone material properties remain debatable. In this study, we collected 36 fresh-frozen cuboid-shaped cortical specimens from five male bovine femurs and immersed half of the specimens into 4% formalin fixation liquid for 30 days. We then conducted three-point bending tests and used both beam theory method and an optimization method combined with specimen-specific finite element (FE) models to identify material parameters. Through the optimization FE method, the formalin-fixed bones showed a significantly lower Young's modulus (-12%) compared to the fresh-frozen specimens, while no difference was observed using the beam theory method. Meanwhile, both the optimization FE and beam theory methods revealed higher effective failure strains for formalin-fixed bones compared to fresh-frozen ones (52% higher through the optimization FE method and 84% higher through the beam theory method). Hence, we conclude that the formalin fixation has a significant effect on bovine cortical bones at small, elastic, as well as large, plastic deformations.

  8. MRI of the temporo-mandibular joint: which sequence is best suited to assess the cortical bone of the mandibular condyle? A cadaveric study using micro-CT as the standard of reference

    Energy Technology Data Exchange (ETDEWEB)

    Karlo, Christoph A. [University Hospital Zurich, Department of Diagnostic and Interventional Radiology, Zurich (Switzerland); University Children' s Hospital Zurich, Department of Diagnostic Imaging, Zurich (Switzerland); Patcas, Raphael; Signorelli, Luca; Mueller, Lukas [University of Zurich, Clinic for Orthodontics and Pediatric Dentistry, Center of Dental Medicine, Zurich (Switzerland); Kau, Thomas; Watzal, Helmut; Kellenberger, Christian J. [University Children' s Hospital Zurich, Department of Diagnostic Imaging, Zurich (Switzerland); Ullrich, Oliver [University of Zurich, Institute of Anatomy, Faculty of Medicine, Zurich (Switzerland); Luder, Hans-Ulrich [University of Zurich, Section of Orofacial Structures and Development, Center of Dental Medicine, Zurich (Switzerland)

    2012-07-15

    To determine the best suited sagittal MRI sequence out of a standard temporo-mandibular joint (TMJ) imaging protocol for the assessment of the cortical bone of the mandibular condyles of cadaveric specimens using micro-CT as the standard of reference. Sixteen TMJs in 8 human cadaveric heads (mean age, 81 years) were examined by MRI. Upon all sagittal sequences, two observers measured the cortical bone thickness (CBT) of the anterior, superior and posterior portions of the mandibular condyles (i.e. objective analysis), and assessed for the presence of cortical bone thinning, erosions or surface irregularities as well as subcortical bone cysts and anterior osteophytes (i.e. subjective analysis). Micro-CT of the condyles was performed to serve as the standard of reference for statistical analysis. Inter-observer agreements for objective (r = 0.83-0.99, P < 0.01) and subjective ({kappa} = 0.67-0.88) analyses were very good. Mean CBT measurements were most accurate, and cortical bone thinning, erosions, surface irregularities and subcortical bone cysts were best depicted on the 3D fast spoiled gradient echo recalled sequence (3D FSPGR). The most reliable MRI sequence to assess the cortical bone of the mandibular condyles on sagittal imaging planes is the 3D FSPGR sequence. (orig.)

  9. 皮质骨块加松质骨治疗牙槽嵴裂的临床研究%Clinical study on the treatment of alveolar cleft with cortical bone block affiliate with cancellous bone

    Institute of Scientific and Technical Information of China (English)

    陈恒丕; 王涛

    2013-01-01

    目的:牙槽嵴裂常与唇腭裂伴发,表现为牙槽嵴的骨质缺损。目前,自体髂骨移植治疗牙槽嵴裂是目前的最广泛治疗方式。但髂骨松质骨移植吸收率高,移植的最终治疗效果并不能完全满足临床要求。本研究采用皮质骨块加松质骨移植治疗牙槽嵴裂,了解是否能提高治疗效果。材料和方法:牙槽嵴裂患者21例,采用髂骨植骨,包括髂骨皮质骨块加骨松质移植和单纯松质骨移植两种方式。术后6个月,采用锥形束CT复查获取影像学资料,对比两种治疗方式的影像学资料中的牙槽骨的剩余量,确定治疗效果。结果:通过髂骨皮质骨块加松质骨移植后的牙槽骨的剩余量大于单纯松质骨移植的牙槽骨的剩余量。结论:对于治疗牙槽嵴裂,皮质骨块加松质骨移植作为一种治疗方法能够提高治疗效果。%Objective :Autologous bone grafts are widely used to treat alveolar cleft associated with cleft lip and palate , showing alveolar bone defects . However ,due to the high absorption rate of iliac cancellous bone grafts ,the clinical requirements are not fully satisfied .In this study ,cortical bone block affiliate with cancellous bone were used to treat alveolar cleft to determine whether there could be any improvement on therapeutic results .Materials and Methods :21 patients with alveolar cleft were treated with cortical bone block affiliate with cancellous bone grafts and cancellous bone grafts from iliac .Six months after the surgical procedures ,Cone-beam CT scanning were executed and the volume of bone of each type of the two treatment methods was calculated to find out the therapeutic results .Results :The volume of alveolar bone formed from cortical bone block affiliate with cancellous bone grafts is greater than cancellous bone grafts alone .Conclusions :For treatment of alveolar cleft ,cortical bone block affiliate with cancellous bone grafts is one method

  10. An Ultrasonic Backscatter Instrument for Cancellous Bone Evaluation in Neonates

    Directory of Open Access Journals (Sweden)

    Chengcheng Liu

    2015-09-01

    Full Text Available Ultrasonic backscatter technique has shown promise as a noninvasive cancellous bone assessment tool. A novel ultrasonic backscatter bone diagnostic (UBBD instrument and an in vivo application for neonatal bone evaluation are introduced in this study. The UBBD provides several advantages, including noninvasiveness, non-ionizing radiation, portability, and simplicity. In this study, the backscatter signal could be measured within 5 s using the UBBD. Ultrasonic backscatter measurements were performed on 467 neonates (268 males and 199 females at the left calcaneus. The backscatter signal was measured at a central frequency of 3.5 MHz. The delay (T1 and duration (T2 of the backscatter signal of interest (SOI were varied, and the apparent integrated backscatter (AIB, frequency slope of apparent backscatter (FSAB, zero frequency intercept of apparent backscatter (FIAB, and spectral centroid shift (SCS were calculated. The results showed that the SOI selection had a direct influence on cancellous bone evaluation. The AIB and FIAB were positively correlated with the gestational age (|R| up to 0.45, P10 µs. Moderate positive correlations (|R| up to 0.45, P10 µs. The T2 mainly introduced fluctuations in the observed correlation coefficients. The moderate correlations observed with UBBD demonstrate the feasibility of using the backscatter signal to evaluate neonatal bone status. This study also proposes an explicit standard for in vivo SOI selection and neonatal cancellous bone assessment.

  11. Effect of weight-bearing exercise and calcium supplement on cortical and trabecular bone in the proximal tibia metaphyseal- an experimental protocol in ovariectomized rats

    Directory of Open Access Journals (Sweden)

    Valliollah Dabidy Roshan1

    2009-01-01

    Full Text Available (Received 4 April, 2009; Accepted 17 June, 2009AbstractBackground and purpose: Osteoporotic fractures are much more common in older post-menopausal women and account for significant morbidity and mortality. Although age is an independent risk factor for fractures, bone micro-architecture is the predictor of subsequent fractures. Adequate calcium and Weight-bearing exercise are known to affect skeletal development, however, the effects of calcium supplement and treadmill endurance running on bone micro-architecture are not well known. The objective of this study was to determine the effects of treadmill endurance running training and calcium supplement, on micro-architectures of cortical and trabecular bone in the proximal tibia metaphyseal in ovariectomized Sprague Dawley rats.Materials and methods: Forty-three rats were randomly divided into endurance running training, calcium supplement, control, pre-test and base groups. The rats in the treadmill running group performed the progressive running exercise in 12 to 20 m/minutes for a total of 10 to 60 minutes, 5 times a week. Calcium group received ca supplement using Gavage (35 mg/kg/day for 8 weeks. After 8 weeks, micro-architecture parameters in the proximal tibia metaphyseal were measured by using a semi-automated image analysis system.Results: The ovariectomay was associated with a significant decrease in the trabecular volume and thickness, while separation insignificantly decreased in the cortical volume and thickness in the proximal tibia metaphyseal. The treadmill running exercise and calcium supplement significantly increased cortical or trabecular volume and also thickness and the trabecular separation compared with age-matched controls. Furthermore, the micro-architectures of cortical and trabecular bone in the proximal tibia metaphyseal was insignificant between the treadmill endurance running and calcium supplement groups.Conclusion: Skeletal benefits can be obtained by changes in

  12. A procedure for the evaluation of 2D radiographic texture analysis to assess 3D bone micro-architecture

    Science.gov (United States)

    Apostol, Lian; Peyrin, Francoise; Yot, Sophie; Basset, Olivier; Odet, Christophe; Tabary, Joachim; Dinten, Jean-Marc; Boller, Elodie; Boudousq, Vincent; Kotzki, Pierre-Olivier

    2004-05-01

    Although the diagnosis of osteoporosis is mainly based on Dual X-ray Absorptiometry, it has been shown that trabecular bone micro-architecture is also an important factor in regards of fracture risk, which can be efficiently assessed in vitro using three-dimensional x-ray microtomography (μCT). In vivo, techniques based on high-resolution s-ray radiography associated to texture analysis have been proposed to investigate bone micro-architecture, but their relevance for giving pertinent 3D information is unclear. The purpose of this work was to develop a method for evaluating the relationships betweeen 3D micro-architecture and 2D texture parameters, and optimizing the conditions for radiographic imaging. Bone sample images taken from cortical to cortical were acquired using 3D-synchrotron x-ray μCT at the ESRF. The 3D digital imagees were further used for two purposes: 1) quantification of three-dimensional bone micro-architecture, 2) simulation of realistic x-ray radiographs under different acquisition conditions. Texture analysis was then applied to these 2D radiographs using a large variety of methods (co-occurence, spectrum, fractal...). First results of the statistical analysis between 2D and 3D parameters allowed identfying the most relevant 2D texture parameters.

  13. Compressive mechanical compatibility of anisotropic porous Ti6Al4V alloys in the range of physiological strain rate for cortical bone implant applications.

    Science.gov (United States)

    Li, Fuping; Li, Jinshan; Kou, Hongchao; Huang, Tingting; Zhou, Lian

    2015-09-01

    Porous titanium and its alloys are believed to be promising materials for bone implant applications, since they can reduce the "stress shielding" effect by tailoring porosity and improve fixation of implant through bone ingrowth. In the present work, porous Ti6Al4V alloys for biomedical application were fabricated by diffusion bonding of alloy meshes. Compressive mechanical behavior and compatibility in the range of physiological strain rate were studied under quasi-static and dynamic conditions. The results show that porous Ti6Al4V alloys possess anisotropic structure with elongated pores in the out-of-plane direction. For porous Ti6Al4V alloys with 60-70 % porosity, more than 40 % pores are in the range of 200-500 μm which is the optimum pore size suited for bone ingrowth. Quasi-static Young's modulus and yield stress of porous Ti6Al4V alloys with 30-70 % relative density are in the range of 6-40 GPa and 100-500 MPa, respectively. Quasi-static compressive properties can be quantitatively tailored by porosity to match those of cortical bone. Strain rate sensitivity of porous Ti6Al4V alloys is related to porosity. Porous Ti6Al4V alloys with porosity higher than 50 % show enhanced strain rate sensitivity, which is originated from that of base materials and micro-inertia effect. Porous Ti6Al4V alloys with 60-70 % porosity show superior compressive mechanical compatibility in the range of physiological strain rate for cortical bone implant applications.

  14. Microcomputed tomographic analysis of human condyles in unilateral condylar hyperplasia: increased cortical porosity and trabecular bone volume fraction with reduced mineralisation.

    Science.gov (United States)

    Karssemakers, L H E; Nolte, J W; Tuinzing, D B; Langenbach, G E J; Raijmakers, P G; Becking, A G

    2014-12-01

    Unilateral condylar hyperplasia or hyperactivity is a disorder of growth that affects the mandible, and our aim was to visualise the 3-dimensional bony microstructure of resected mandibular condyles of affected patients. We prospectively studied 17 patients with a clinical presentation of progressive mandibular asymmetry and an abnormal single-photon emission computed tomographic (SPECT) scan. All patients were treated by condylectomy to arrest progression. The resected condyles were scanned with micro-CT (18 μm resolution). Rectangular volumes of interest were selected in 4 quadrants (lateromedial and superoinferior) of the trabecular bone of each condyle. Variables of bone architecture (volume fraction, trabecular number, thickness, and separation, degree of mineralisation, and degree of structural anisotrophy) were calculated with routine morphometric software. Eight of the 17 resected condyles showed clear destruction of the subchondral layer of cortical bone. There was a significant superoinferior gradient for all trabecular variables. Mean (SD) bone volume fraction (25.1 (6) %), trabecular number (1.69 (0.26) mm(-1)), trabecular thickness (0.17 (0.03) mm), and degree of mineralisation (695.39 (39.83) mg HA/cm(3)) were higher in the superior region. Trabecular separation (0.6 (0.16) mm) and structural anisotropy (1.84 (0.28)) were higher in the inferior region. The micro-CT analysis showed increased cortical porosity in many of the condyles studied. It also showed a higher bone volume fraction, greater trabecular thickness and trabecular separation, greater trabecular number, and less mineralisation in the condyles of the 17 patients compared with the known architecture of unaffected mandibular condyles.

  15. Efeitos do processamento químico e da esterilização em Óxido de etileno em osso cortical e esponjoso de ratas: estudo com microscopia de luz e eletrônica de varredura Effects of chemical processing and oxide ethylene sterilization on cortical and cancellous rat bone: a light and electron scanning microscopy study

    Directory of Open Access Journals (Sweden)

    Marcello Teixeira Castiglia

    2009-02-01

    Full Text Available OBJETIVO: Avaliar, sob o ponto de vista microscópico, modificações estruturais do osso esponjoso e cortical, após serem submetidos a processamento químico e esterilização em óxido de etileno. MÉTODOS: Amostras de osso esponjoso e cortical foram obtidas de fêmures de ratas albinas jovens (Wistare separadas em quatro grupos contendo osso cortical e esponjoso: I- Fragmentos secos em estufa; II- Fragmentos secos em estufa e esterilizados em óxido de etileno; III- Fragmentos processados quimicamente; IV- Fragmentos processados quimicamente e esterilizados em óxido de etileno. Metade desse material foi analisada em microscópio eletrônico de varredura e, a outra metade, em microscopia de luz convencional. RESULTADOS: Houve preservação da morfologia geral das amostras em todos os grupos. Nos grupos submetidos ao processamento químico houve melhor preservação do conteúdo celular, enquanto que naqueles submetido ao óxido de etileno houve amalgamação fibrilar. CONCLUSÃO: O tratamento com óxido de etileno causou amalgamação das fibrilas possivelmente em decorrência do efeito do calor e o tratamento químico contribuiu para melhor preservação da estrutura óssea.OBJECTIVE: To evaluate, under microscopic examination, the structural changes displayed by the trabecular and cortical bones after being processed chemically and sterilized by ethylene oxide. METHODS: Samples of cancellous and cortical bones obtained from young female albinus rats (Wistar were assigned to four groups according to the type of treatment: Group I-drying; Group II-drying and ethylene oxide sterilization; III-chemical treatment; IV-chemical treatment and ethylene oxide sterilization. Half of this material was analyzed under ordinary light microscope and the other half using scanning electron microscopy. RESULTS: In all the samples, regardless the group, there was good preservation of the general morphology. For samples submitted to the chemical processing

  16. Analysis of bone mineral density of human bones for strength evaluation

    Indian Academy of Sciences (India)

    S N Khan; R M Warkhedkar; A K Shyam

    2015-08-01

    The bone density (BMD) is a medical term normally referring to the amount of mineral matter per square centimetre of bones. Twenty-five patients (18 female and 7 male patients with a mean age of 71.3 years) undergoing both lumbar spine DXA scans and computed tomography imaging were evaluated to determine if HU correlates with BMD and T-scores. BMD is used in clinical medicine as an indirect indicator of osteoporosis and fracture risk. This medical bone density is not the true physical ``density'' of the bone, which would be computed as mass per volume. Dual-energy X-ray absorptiometry (DXA, previously DEXA), a means of measuring BMD, is the most widely used and most thoroughly studied bone density measurement technologies. Different types of bone strength are required for various applications, but this strength calculation requires different machines for each strength property or it is done by different software like X-ray, CT scan, DEXA and BIA. The paper includes the design of an experimental setup which performs different types of test like tension, compression, three point bending, four point bending and torsion. The modified correlation between BMD and HU for various strength calculations is found out and validated with the experimental results.

  17. Preclinical evaluation of strontium-containing bioactive bone cement

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhaoyang, E-mail: lizy@hku.hk [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Department of Orthopaedics and Traumatology, The University of Hong Kong, Hong Kong (China); Yuan, Ning [Department of Laboratory Medicine, Tianjin Chest Hospital, Tianjin 300051 (China); Lam, Raymond Wing Moon [Department of Orthopaedics and Traumatology, The University of Hong Kong, Hong Kong (China); Cui, Zhenduo; Yang, Xianjin [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Lu, William Weijia, E-mail: wwlu@hku.hk [Department of Orthopaedics and Traumatology, The University of Hong Kong, Hong Kong (China)

    2013-12-01

    Strontium (Sr) has become more attractive for orthopaedic applications as they can simultaneously stimulate bone formation and prevent bone loss. A Sr-containing bioactive bone cement (Sr-BC) has been designed to fix osteoporotic bone fracture. Sr is a trace element, so the safety of containing Sr is concerned when Sr-BC is implanted in human body. The preclinical assessment of biocompatibility of Sr-BC was conducted according to ISO 10993 standards. MTT assay showed that this bioactive bone cement was non-toxic to mouse fibroblasts, and it met the basic requirement for the orthopaedic implant. The three independent genetic toxicity studies including Ames, chromosome aberration and bone marrow micronucleus assays demonstrated absence of genotoxic components in Sr-BC, which reassured the safety concerns of this novel bone cement. The muscle implantation results in present study were also encouraging. The acute inflammation around the cement was observed at 1 week post-implantation; however, no significant difference was observed between control and Sr-BC groups. These responses may be attributed to the presence of the foreign body, but the tissue healed after 12 weeks implantation. In summary, the above preclinical results provide additional assurance for the safety of this implant. Sr-BC can be used as a potential alternative to the traditional bone cement. - Highlights: • Strontium-containing bioactive bone cement (Sr-BC) was designed. • The biocompatibility of Sr-BC was evaluated according ISO 10993 standards. • Preclinical results provide additional assurance for the safety of Sr-BC.

  18. CBCT-based evaluation of integrity of cortical sinus close to periapical lesions

    Directory of Open Access Journals (Sweden)

    Oséas SANTOS Junior

    2015-01-01

    Full Text Available The purpose of the present study was to test the applicability of cone beam computed tomography (CBCT to evaluate the integrity of the cortical sinus close to periapical lesions. Two observers analyzed samples of 64 alveoli of first molar roots in macerated swine maxillas prepared with perchloric acid to simulate periapical lesions. The specimens were evaluated using CBCT (55-mm high and 100-mm diameter cylinder at 0.2-mm voxel resolution for the presence of oroantral communication (OAC caused by the simulated lesions. Sensitivity, specificity, and accuracy were calculated. Fair values were obtained for accuracy (66%-78% and good values for specificity (70%-98%, whereas the values for sensibility showed relevant variation (41%-78%. For this reason, the interobserver agreement score was weak. CBCT proved capable of evaluating the integrity of the cortical sinus (absence of oroantral communication when it lies close to an apical periodontitis lesion. However, the low interobserver agreement reflects the difficulty in performing diagnoses when OAC is adjacent to a periapical lesion, using the acquisition protocol adopted in this research. This could be attributed to the high level of image noise.

  19. Stereomicroscopic evaluation of the joint cartilage and bone tissue in osteoporosis

    Science.gov (United States)

    Vasile, Liliana; Torok, Rodica; Deleanu, Bogdan; Marchese, Cristian; Valeanu, Adina; Bodea, Rodica

    2012-06-01

    Aim of the study. Assessment by stereomicroscopy of the severity of lesions in osteoporotic bone at both sexes and to correlate micro-and macro-bone fracture due to low bone density values with the disease evolution. Material and method: The study material consists of fragments of bone from the femoral head, vertebral bone, costal and iliac crest biopsy obtained from patients aged over 70 years, female and male, treated in the County Hospital of Timisoara, Department of Orthopedics. For the purpose of studying the samples in stereomicroscopy and trough polarized light it has been used the Olympus Microscope SZ ×7 and an Olympus camera with 2,5 × digital zoom and a 3× optical zoom in the Vest Politechnic Univesity. Results and discussions: Subchondral bone presents osteolysis associated with a osteoporotic bone transformation. Pseudocystic chondrolisis was noted in the osteoarticular cartilage, in addition with areas of hemorrhagic postfractural necrosis. The osteoporotic bone exhibits ischemic necrosis and focal hemorrhagic necrosis adjacent fracture. Microporosity pattern of the bone observed by stereomicroscopy correspond to the spongy bone osteoporosis images. Morphometry of the bone spiculi reveals length of 154.88 and 498.32 μ. In men we found a greater thickness of bone trabeculi compared with bone texture porosity in women. The subchondral bone supports and fulfills an important role in transmitting forces from the overlying articular cartilage inducing the bone resorbtion. The femoral head fracture may be the final event of many accumulated bone microcracks. Conclusions: Bone fragility depends not only of the spongy bone but also of the cortical bone properties. Osteolysis produced by loss of balance in the process of remodeling in favor of bone resorption leads to the thinning of the subchondral bone at both sexes.

  20. Mechanochemical synthesis evaluation of nanocrystalline bone-derived bioceramic powder using for bone tissue engineering

    Directory of Open Access Journals (Sweden)

    Amirsalar Khandan

    2014-01-01

    Full Text Available Introduction: Bone tissue engineering proposes a suitable way to regenerate lost bones. Different materials have been considered for use in bone tissue engineering. Hydroxyapatite (HA is a significant success of bioceramics as a bone tissue repairing biomaterial. Among different bioceramic materials, recent interest has been risen on fluorinated hydroxyapatites, (FHA, Ca 10 (PO 4 6 F x (OH 2−x . Fluorine ions can promote apatite formation and improve the stability of HA in the biological environments. Therefore, they have been developed for bone tissue engineering. The aim of this study was to synthesize and characterize the FHA nanopowder via mechanochemical (MC methods. Materials and Methods: Natural hydroxyapatite (NHA 95.7 wt.% and calcium fluoride (CaF 2 powder 4.3 wt.% were used for synthesis of FHA. MC reaction was performed in the planetary milling balls using a porcelain cup and alumina balls. Ratio of balls to reactant materials was 15:1 at 400 rpm rotation speed. The structures of the powdered particles formed at different milling times were evaluated by X-ray diffraction (XRD, scanning electron microscopy (SEM and transmission electron microscopy (TEM. Results: Fabrication of FHA from natural sources like bovine bone achieved after 8 h ball milling with pure nanopowder. Conclusion: F− ion enhances the crystallization and mechanical properties of HA in formation of bone. The produced FHA was in nano-scale, and its crystal size was about 80-90 nm with sphere distribution in shape and size. FHA powder is a suitable biomaterial for bone tissue engineering.

  1. Posterior lumbar interbody fusion with cortical bone trajectory screw fixation versus posterior lumbar interbody fusion using traditional pedicle screw fixation for degenerative lumbar spondylolisthesis: a comparative study.

    Science.gov (United States)

    Sakaura, Hironobu; Miwa, Toshitada; Yamashita, Tomoya; Kuroda, Yusuke; Ohwada, Tetsuo

    2016-11-01

    OBJECTIVE Several biomechanical studies have demonstrated the favorable mechanical properties of the cortical bone trajectory (CBT) screw. However, no reports have examined surgical outcomes of posterior lumbar interbody fusion (PLIF) with CBT screw fixation for degenerative spondylolisthesis (DS) compared with those after PLIF using traditional pedicle screw (PS) fixation. The purposes of this study were thus to elucidate surgical outcomes after PLIF with CBT screw fixation for DS and to compare these results with those after PLIF using traditional PS fixation. METHODS Ninety-five consecutive patients underwent PLIF with CBT screw fixation for DS (CBT group; mean followup 35 months). A historical control group consisted of 82 consecutive patients who underwent PLIF with traditional PS fixation (PS group; mean follow-up 40 months). Clinical status was assessed using the Japanese Orthopaedic Association (JOA) scale score. Fusion status was assessed by dynamic plain radiographs and CT. The need for additional surgery and surgery-related complications was also evaluated. RESULTS The mean JOA score improved significantly from 13.7 points before surgery to 23.3 points at the latest follow-up in the CBT group (mean recovery rate 64.4%), compared with 14.4 points preoperatively to 22.7 points at final follow-up in the PS group (mean recovery rate 55.8%; p fusion was achieved in 84 patients from the CBT group (88.4%) and in 79 patients from the PS group (96.3%, p > 0.05). Symptomatic adjacent-segment disease developed in 3 patients from the CBT group (3.2%) compared with 9 patients from the PS group (11.0%, p fusion rate tended to be lower in the CBT group than in the PS group, although the difference was not statistically significant between the 2 groups.

  2. Distribution of bone density and cortical thickness in the proximal femur and their association with hip fracture in postmenopausal women: a quantitative computed tomography study.

    Science.gov (United States)

    Yang, L; Udall, W J M; McCloskey, E V; Eastell, R

    2014-01-01

    The quantitative computed tomography (QCT) scans in an individually matched case-control study of women with hip fracture were analysed. There were widespread deficits in the femoral volumetric bone mineral density (vBMD) and cortical thickness of cases, and cortical vBMD and thickness discriminated hip fracture independently of BMD by dual-energy X-ray absorptiometry (DXA). Acknowledging the limitations of QCT associated with partial volume effects, we used QCT in an individually matched case-control study of women with hip fracture to better understand its structural basis. Fifty postmenopausal women (55-89 years) who had sustained hip fractures due to low-energy trauma underwent QCT scans of the contralateral hip within 3 months of the fracture. For each case, postmenopausal women, matched by age (±5 years), weight (±5 kg) and height (±5 cm), were recruited as controls. We quantified cortical, trabecular and integral vBMD and apparent cortical thickness (AppCtTh) in four quadrants of cross-sections along the length of the femoral head (FH), femoral neck (FN), intertrochanter and trochanter and examined their association with hip fracture. Women with hip or intracapsular (IC) fracture had significantly (p hip and IC fractures independent of hip areal BMD (aBMD). The combination of AppCtTh and trabecular or integral vBMD discriminated hip fracture, whereas the combination of FH and FN AppCtTh discriminated IC fracture significantly (p hip aBMD. Deficits in vBMD and AppCtTh in cases were widespread in the proximal femur, and cortical vBMD and AppCtTh discriminated hip fracture independently of aBMD by DXA.

  3. Influence of Parathyroidectomy on Bone Calcium Concentration: Evaluation with Spectral CT in Patients with Secondary Hyperparathyroidism Undergoing Hemodialysis-A Prospective Feasibility Study.

    Science.gov (United States)

    Ma, Qiang; Yang, Zhenghan; Han, Xue; Liu, Fen; Su, Dechun; Xing, Haidong

    2017-02-07

    Purpose To use spectral computed tomography (CT) to evaluate the influence of parathyroidectomy (PTX) on calcium concentration in trabecular bone and cortical bone in patients undergoing hemodialysis with secondary hyperparathyroidism. Materials and Methods This study was performed with institutional review board approval. Written consent was obtained from each patient. Thirty-eight men (mean age ± standard deviation, 55.69 years ± 8.05; range, 42-72 years) undergoing maintenance hemodialysis who underwent PTX and 40 patients (mean age, 56.71 years ± 9.53; range, 45-74 years) who did not undergo PTX received prospective follow-up for 2 years. Bone calcium concentration was measured in the cortical compartment of the bilateral proximal femur and the medullary compartment of the lumbar vertebral bodies (L1 through L3) on the basis of calcium-based material decomposition images of a spectral CT examination. The differences between baseline and end-of-study PTX parameters were analyzed with the paired Student t test. Results For patients who underwent PTX, mean cortical bone calcium concentration increased from 220.69 mg/cm(3) ± 25.79 to 257.43 mg/cm(3) ± 25.46 (t = 8.546, P < .001), whereas medullary bone calcium concentration decreased from 64.75 mg/cm(3) ± 15.07 to 61.42 mg/cm(3) ± 15.77 (t = 22.293, P < .001) from baseline to follow-up. In patients who did not undergo PTX, mean cortical bone calcium concentration decreased from 296.08 mg/cm(3) ± 36.35 to 258.35 mg/cm(3) ± 31.46 (t = 7.420, P < .001), but medullary bone calcium concentration increased from 61.13 mg/cm(3) ± 13.85 to 62.94 mg/cm(3) ± 14.80 (t = 2.370, P = .023) from baseline to follow-up. Conclusion During the course of chronic renal failure, different bone elements involve various pathologic changes. PTX could reverse long-term cortical bone loss reflected in calcium concentration measured with spectral CT; however, it could induce medullary bone loss. (©) RSNA, 2017 Online supplemental

  4. High-fat Diet Decreases Cancellous Bone Mass But Has No Effect on Cortical Bone Mass in the Tibia in Mice

    Science.gov (United States)

    Introduction: Body mass has a positive effect on bone mineral density and the strength. Whether mass derived from an obesity condition is beneficial to bone has not been established; neither have the mechanism by which obesity affects bone metabolism. The aim of this study was to examine the effects...

  5. Evaluation of laser photobiomodulation on healing of bone defects grafted with bovine bone in diabetic rats

    Science.gov (United States)

    Paraguassú, Gardênia Matos; da Costa Lino, Maíra Doria Martinez; de Carvalho, Fabíola Bastos; Cangussu, Maria Cristina; Pinheiro, Antônio Luiz Barbosa; Ramalho, Luciana Maria Pedreira

    2012-09-01

    Previous studies have shown positive effects of Low Level Laser Therapy (LLLT) on the repair of bone defects, but there is a few that associates bone healing in the presence of a metabolic disorder such as Diabetes Mellitus, a systemic disorder associated to impair of the repair of different tissues. The aim of this study was to assess, histologically, the repair of surgical defects created in the femur of diabetic and non-diabetic rats treated or not with LLLT (λ780nm, 70mW, CW, o/˜0.4mm, 16J/cm2 per session) associated or not to the use of a biomaterial. Surgical tibial bone defects were created in 60 animals that were divided into 4 groups: Group B (non-diabetic + biomaterial); Group BL (non-diabetic + biomaterial + LLLT); Group BD (diabetic + biomaterial); Group BDL (diabetic + biomaterial + LLLT). The irradiated group received 16 J/cm2 per session divided into 4 points around the defect, being the first irradiation carried out immediately after surgery and repeated every 48h for 14 days. The animals were killed 15, 21 and 30 days after surgery. The specimens underwent a semi-quantitative analysis. The results showed inflammation more intense in the BD and BDL groups than in the B and BL groups in the period of 15 days (p = 0.02), however the cortical repair in the BDL group was below 25% in more than half of the specimens, while in the BD group, the repair was more than to 25% in all specimens. At 30 days, both osteoblastic activity and collagen deposition were significantly higher in the B group when compared to the BD group (p=0.04). Bone deposition was significantly higher in the BL group (p=0.023) than in BDL group. It is concluded that LLLT has a positive biomodulative effect in the early stages of the healing process of bone defects grafted with biomaterial in diabetic and non-diabetic rats.

  6. Efeito do enxerto ósseo corticoesponjoso na osteogênese em falha cortical ulnar de galinhas domésticas (Gallus domesticus Effect of cortico-cancellous bone grafting in osteogenisis of cortical ulnar failure of domestic chickens (Gallus domesticus

    Directory of Open Access Journals (Sweden)

    D.A. Balthazar

    2013-02-01

    Full Text Available O objetivo do estudo foi avaliar o efeito do enxerto ósseo corticoesponjoso na osteogênese em falha cortical ulnar de galinhas domésticas. Foram utilizadas 18 galinhas, com aproximadamente 70 semanas de idade e peso corpóreo médio de 2,5kg. Criou-se uma falha óssea na porção diafisária média da ulna em ambas as asas, sendo a direita utilizada como grupo-controle (grupo I e a esquerda como grupo-tratado (grupo II. As aves foram subdivididas aleatoriamente em quatro subgrupos de acordo com o período de observação (14, 35, 60 e 90 dias. No grupo II, dois fragmentos ósseos da carena do esterno foram retirados, seccionados e implantados na falha óssea. Ao término do período de observação de cada subgrupo, as aves foram abatidas com tiopental sódico para realização dos exames histopatológico e radiográfico post-mortem, com classificação dos resultados em escala semiquantitativa (escore. O grupo II demonstrou osteogênese mais evidente aos 35 e 90 dias de pós-cirúrgico (PThe aim of this survey was to evaluate the effect of cortico-cancellous bone grafting in osteogenesis in cortical ulnar failure in domestic chickens. Eighteen chickens weighing 2.5kg with approximately 70 weeks of age were used. A bone defect in the middle portion of the ulna shaft was created in both wings; the right wing in the control group (Group I and the left in the treated group (Group II. The birds were randomly divided into four subgroups according to the observation period (14, 35, 60 and 90 days. In group II, two bone fragments of the keel of the sternum were removed, sectioned and implanted in the bone defects. At the end of the observation period for each subgroup, the birds were euthanaized with sodium thiopental to perform the histopathological and radiographic postmortem, with ranking of results in a semi-quantitative scale (score. Group II showed a more evident osteogenisis at 35 and 90 days after surgery (P<0.05. In comparing both groups

  7. Autologous grafts of double-strut fibular cortical bone plate to treat the fractures and defects of distal femur: a case report and review of literature

    Directory of Open Access Journals (Sweden)

    CHEN Xu

    2012-02-01

    Full Text Available 【Abstract】We reported a 23-year-old man who was involved in a high-speed motorcycle accident. He sustained a closed fracture at the right distal femur. The primary fracture happened on February 2008. He underwent open reduction and internal fixation with cloverleaf plate. And one hundred days after the surgery, the proximal screws were pulled-out, but the bone union was not achieved. Treatment consisted of exchanging the cloverleaf plate with a locking compression plate and using an auto-iliac bone graft to fill the nonunion gap. In July 2009, the patient had a sharp pain in the right lower limb. The X-ray revealed that the plate implanted last year was broken, causing a nonunion at the fracture site. Immediately the plate and screws were removed and an intramedullary nail was inserted reversely from the distal femur as well as a 7 cm long bone from the right fibula was extracted and longitudinally split into two pieces to construct cortical bone plates. Then we placed them laterally and medially to fracture site, drilled two holes respectively, and fastened them with suture. We carried on auto-iliac bone grafting with the nonunion bone grafts. The follow-up at 15 months after operation showed that the treatment was successful, X-ray confirmed that there was no rotation and no angular or short deformity. We briefly reviewed the literature regarding such an unusual presentation and discussed in details the possible etiology and the advantages of autologous double-strut fibular grafts to cope with such an intractable situation. Key words: Femur; Transplantation, autologous; Bone screws

  8. Age-related changes in collagen properties and mineralization in cancellous and cortical bone in the porcine mandibular condyle

    NARCIS (Netherlands)

    Willems, N.M.B.K.; Langenbach, G.E.J.; Everts, V.; Mulder, L.; Grünheid, T.; Bank, R.A.; Zentner, A.; Eijden, T.M.G.J. van

    2010-01-01

    Collagen is an important constituent of bone, and it has been suggested that changes in collagen and mineral properties of bone are interrelated during growth. The aim of this study was to quantify age-related changes in collagen properties and the degree of mineralization of bone (DMB). The DMB in

  9. Evaluation of bone tissue reaction in laser beamed implants

    Energy Technology Data Exchange (ETDEWEB)

    Allegrini, Sergio, E-mail: sergiojr@usp.br [Graduate Program in Biodentistry, Ibirapuera University (UNIB), São Paulo, SP, 04661 100 (Brazil); Yoshimoto, Marcelo [Graduate Program in Biodentistry, Ibirapuera University (UNIB), São Paulo, SP, 04661 100 (Brazil); Salles, Marcos Barbosa [Department of Oral and Maxillofacial Surgery, Nove de Julho University (UNINOVE), São Paulo, SP, 02117 010 (Brazil); Allegrini, Marcia Rivellino Facci [São Paulo Fire Department (SPFD) of the Militar Police, Dentistry Section, São Paulo, SP, 01018 001 (Brazil); Pistarini, Luciana Crepaldi Yazawa; Braga, Francisco Jose Correa; Bressiani, Ana Helena de Almeida [Nuclear and Energy Research Institute – IPEN/USP, São Paulo, SP, 05508 900 (Brazil)

    2014-07-01

    The purpose of this study was to evaluate alterations and bone tissue response on laser treated implant surfaces (Nd:YAG – 100 W). Sixty grade II titanium (ASTM F67) mini-implants (1.5 mm × 4.0 mm) were installed in femurs of 30 Wistar rats. The animals were divided into two groups: thirty mini-implants were machined elements (Machined Group) and the other thirty had laser beamed surfaces (Laser Group). The animals were subdivided into three groups, according to bone healing periods of 15, 30 and 60 days. The samples were analyzed under light, scanning electron and confocal 3D microscopy as well as by EDS (energy dispersive spectroscopy) and Student's t test was used for statistical analyses. Light microscopy results showed new bone trabeculae formation toward laser-treated implants at 15 days’ bone repair as well as thin layers of osteoid matrix, indicating high biocompatibility. Similar features were observed in the Machined Group but only after 30 days. Bone/implant contact was better evidenced on laser-treated surfaces compared to that on simply machined implants. The only group that demonstrated change in level of significance was the laser-treated group at the 15-day-healing period (p < 0.05). Higher oxygen concentration possibly provides more efficient response of osteoblasts during new bone tissue deposition. Implant treated surfaces altered by laser beaming, their composition, surface topography and surface energy may be the future scene in implant dentistry.

  10. Stress Distribution on Short Implants at Maxillary Posterior Alveolar Bone Model With Different Bone-to-Implant Contact Ratio: Finite Element Analysis.

    Science.gov (United States)

    Yazicioglu, Duygu; Bayram, Burak; Oguz, Yener; Cinar, Duygu; Uckan, Sina

    2016-02-01

    The aim of this study was to evaluate the stress distribution of the short dental implants and bone-to-implant contact ratios in the posterior maxilla using 3-dimensional (3D) finite element models. Two different 3D maxillary posterior bone segments were modeled. Group 1 was composed of a bone segment consisting of cortical bone and type IV cancellous bone with 100% bone-to-implant contact. Group 2 was composed of a bone segment consisting of cortical bone and type IV cancellous bone including spherical bone design and homogenous tubular hollow spaced structures with 30% spherical porosities and 70% bone-to-implant contact ratio. Four-millimeter-diameter and 5-mm-height dental implants were assumed to be osseointegrated and placed at the center of the segments. Lateral occlusal bite force (300 N) was applied at a 25° inclination to the implants long axis. The maximum von Mises stresses in cortical and cancellous bones and implant-abutment complex were calculated. The von Mises stress values on the implants and the cancellous bone around the implants of the 70% bone-to-implant contact group were almost 3 times higher compared with the values of the 100% bone-to-implant contact group. For clinical reality, use of the 70% model for finite element analysis simulation of the posterior maxilla region better represents real alveolar bone and the increased stress and strain distributions evaluated on the cortical and cancellous bone around the dental implants.

  11. Is the panoramic mandibular index useful for bone quality evaluation?

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Ah Young; Huh, Kyung Hoe; Yi, Won Jin; Lee, Sam Sun; Choi, Soon Chul; Heo, Min Suk [Dept. of Oral and Maxillofacial Radiology and Dental Research Institute, School of Dentistry, Seoul National University, Seoul (United States)

    2017-06-15

    The aim of this study was to determine whether the panoramic mandibular index (PMI) is useful for assessing bone mineral density. We also analyzed the potential correlations between PMI parameters and patient age. Four observers measured the PMI of both sides of the mental foramen using a picture archiving and communication system and images in the Digital Imaging and Communications in Medicine format. They studied 300 panoramic radiographic images of patients belonging to the following age groups: 40–49 years, 50–59 years, 60–69 years, 70–79 years, and 80–89 years. The observers were allowed to zoom in or out and to adjust the contrast of the images. Further, they were instructed to record the reasons for any measurements that could not be made. Then, we conducted a reliability analysis of the measured PMI and assessed the correlations between different patient age groups and the 3 parameters used for determining the PMI from the available data. Among the 600 data items collected, 23 items were considered unmeasurable by at least 1 observer for the following 4 reasons: postoperative state, lesion, unidentified mental foramen, and alveolar bone loss. The intraobserver reproducibility of the measurable data was 0.611-0.752. The mandibular cortical width (MCW) decreased significantly as patient age increased. PMI had limited usability when the margin of the mental foramen was not clear. In contrast, MCW, a parameter used for determining the PMI, had fewer drawbacks than the PMI with respect to bone mineral density measurements and exhibited a significant correlation with patient age.

  12. Audiometric evaluation of bilaterally fitted bone-anchored hearing aids.

    NARCIS (Netherlands)

    Bosman, A.J.; Snik, A.F.M.; Pouw, C.T.M. van der; Mylanus, E.A.M.; Cremers, C.W.R.J.

    2001-01-01

    Bilateral fittings of bone-anchored hearing aids (BAHA) were evaluated in 25 patients with at least 3 months experience with using two BAHAs. For all patients, air conduction hearing aids were contraindicated due to either recurrent otorrhoea or otitis externa (19 cases) or to congenital aural atres

  13. Intrinsic mechanical behavior of femoral cortical bone in young, osteoporotic and bisphosphonate-treated individuals in low- and high energy fracture conditions

    Science.gov (United States)

    Zimmermann, Elizabeth A.; Schaible, Eric; Gludovatz, Bernd; Schmidt, Felix N.; Riedel, Christoph; Krause, Matthias; Vettorazzi, Eik; Acevedo, Claire; Hahn, Michael; Püschel, Klaus; Tang, Simon; Amling, Michael; Ritchie, Robert O.; Busse, Björn

    2016-02-01

    Bisphosphonates are a common treatment to reduce osteoporotic fractures. This treatment induces osseous structural and compositional changes accompanied by positive effects on osteoblasts and osteocytes. Here, we test the hypothesis that restored osseous cell behavior, which resembles characteristics of younger, healthy cortical bone, leads to improved bone quality. Microarchitecture and mechanical properties of young, treatment-naïve osteoporosis, and bisphosphonate-treated cases were investigated in femoral cortices. Tissue strength was measured using three-point bending. Collagen fibril-level deformation was assessed in non-traumatic and traumatic fracture states using synchrotron small-angle x-ray scattering (SAXS) at low and high strain rates. The lower modulus, strength and fibril deformation measured at low strain rates reflects susceptibility for osteoporotic low-energy fragility fractures. Independent of age, disease and treatment status, SAXS revealed reduced fibril plasticity at high strain rates, characteristic of traumatic fracture. The significantly reduced mechanical integrity in osteoporosis may originate from porosity and alterations to the intra/extrafibrillar structure, while the fibril deformation under treatment indicates improved nano-scale characteristics. In conclusion, losses in strength and fibril deformation at low strain rates correlate with the occurrence of fragility fractures in osteoporosis, while improvements in structural and mechanical properties following bisphosphonate treatment may foster resistance to fracture during physiological strain rates.

  14. Mid-thigh cortical bone structural parameters, muscle mass and strength, and association with lower limb fractures in older men and women (AGES-Reykjavik Study).

    Science.gov (United States)

    Johannesdottir, Fjola; Aspelund, Thor; Siggeirsdottir, Kristin; Jonsson, Brynjolfur Y; Mogensen, Brynjolfur; Sigurdsson, Sigurdur; Harris, Tamara B; Gudnason, Vilmundur G; Lang, Thomas F; Sigurdsson, Gunnar

    2012-05-01

    In a cross-sectional study we investigated the relationship between muscle and bone parameters in the mid-thigh in older people using data from a single axial computed tomographic section through the mid-thigh. Additionally, we studied the association of these variables with incident low-trauma lower limb fractures. A total of 3,762 older individuals (1,838 men and 1,924 women), aged 66-96 years, participants in the AGES-Reykjavik study, were studied. The total cross-sectional muscular area and knee extensor strength declined with age similarly in both sexes. Muscle parameters correlated most strongly with cortical area and total shaft area (adjusted for age, height, and weight) but explained lower limb fractures. Small muscular area, low knee extensor strength, large MA, low cortical thickness, and high BR were significantly associated with fractures in both sexes. Our results show that bone and muscle loss proceed at different rates and with different gender patterns.

  15. Autologous grafts of double-strut fibular cortical bone plate to treat the fractures and defects of distal femur: a case report and review of literature

    Institute of Scientific and Technical Information of China (English)

    CHEN Xu; LI Jian-jun; KONG Zhan; YANG Dong-xiang; YUAN Xiang-nan

    2011-01-01

    We reported a 23-year-old man who was involved in a high-speed motorcycle accident. He sustained a closed fracture at the right distal femur. The primary fracture happened on February 2008. He underwent open reduction and internal fixation with cloverleaf plate. And one hundred days after the surgery, the proximal screws were pulled-out, but the bone union was not achieved. Treat ment consisted of exchanging the cloverleaf plate with a locking compression plate and using an auto-iliac bone graft to fill the nonunion gap. In July 2009, the patient had a sharp pain in the right lower limb. The X-ray revealed that the plate implanted last year was broken, causing a nonunion at the fracture site. Immediately the plate and screws were removed and an intramedullary nail was inserted reversely from the distal femur as well as a 7 cm long bone from the right fibula was extracted and longitudinally split into two pieces to construct cortical bone plates. Then we placed them laterally and medially to fracture site, drilled two holes respectively, and fastened them with suture. We carried on auto-iliac bone grafting with the nonunion bone grafts. The follow-up at 15 months after operation showed that the treatment was successful, X-ray confirmed that there was no rotation and no angular or short deformity. We briefly reviewed the literature regarding such an unusual presentation and discussed in details the possible etiology and the advantages of autologous double-strut fibular grafts to cope with such an intractable situation.

  16. Biomechanical evaluation of implant-supported prosthesis with various tilting implant angles and bone types in atrophic maxilla: A finite element study.

    Science.gov (United States)

    Gümrükçü, Zeynep; Korkmaz, Yavuz Tolga; Korkmaz, Fatih Mehmet

    2017-07-01

    The purpose of this study is to evaluate and compare bone stress that occurs as a result of using vertical implants with simultaneous sinus augmentation with bone stress generated from oblique implants without sinus augmentation in atrophic maxilla. Six, three-dimensional (3D) finite element (FE) models of atrophic maxilla were generated with SolidWorks software. The maxilla models were varied for two different bone types. Models 2a, 2b and 2c represent maxilla models with D2 bone type. Models 3a, 3b and 3c represent maxilla models with D3 bone type. Five implants were embedded in each model with different configurations for vertical implant insertion with sinus augmentation: Model 2a/Model 3a, 30° tilted insertion; Model 2b/Model 3b and 45° tilted insertion; Model 2c/Model 3c. A 150 N load was applied obliquely on the hybrid prosthesis. The maximum von Mises stress values were comparatively evaluated using color scales. The von Mises stress values predicted by the FE models were higher for all D3 bone models in both cortical and cancellous bone. For the vertical implant models, lower stress values were found in cortical bone. Tilting of the distal implants by 30° increased the stress in the cortical layer compared to vertical implant models. Tilting of the distal implant by 45° decreased the stress in the cortical bone compared to the 30° models, but higher stress values were detected in the 45° models compared to the vertical implant models. Augmentation should be the first treatment option in atrophic maxilla in terms of biomechanics. Tilted posterior implants can create higher stress values than vertical posterior implants. During tilting implant planning, the use of a 45° tilted implant results in better biomechanical performance in peri-implant bone than 30° tilted implant due to the decrease in cantilever length. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Inter-observer agreement for the evaluation of bone involvement on Whole Body Low Dose Computed Tomography (WBLDCT) in Multiple Myeloma (MM)

    Energy Technology Data Exchange (ETDEWEB)

    Zacchino, M.; Minetti, V.; Dore, R.; Calliada, F. [University of Pavia, Fondazione IRCCS Policlinico San Matteo, Institute of Radiology, Pavia (Italy); Bonaffini, P.A.; Nasatti, A.; Sironi, S. [University of Milano Bicocca, San Gerardo Hospital, Department of Diagnostic Radiology, Monza (Italy); Corso, A. [University of Pavia, Fondazione IRCCS Policlinico San Matteo, Division of Hematology, Pavia (Italy); Tinelli, C. [University of Pavia, Fondazione IRCCS Policlinico San Matteo, Service of Biometry and Statistics, Pavia (Italy)

    2015-11-15

    We aimed to assess inter-observer agreement in bone involvement evaluation and define accuracy and reproducibility of MDCT images analysis in Multiple Myeloma (MM), by comparing two acquisition protocols at two different institutions. A total of 100 MM patients underwent whole body low-dose computed tomography (WB-LDCT), with two protocols: Group I (50 patients), 80 kV and 200-230 mAs; Group II, 120 kV-40 mAs. Four readers (two experts) retrospectively reviewed 22 anatomical districts, reporting the following for each patient: 1) osteolytic lesions; 2) cortical bone integrity; 3) fractures; 4) risk of vertebral collapse; 5) hyperattenuating bone lesions; and 6) extraosseous extension. Inter-observer agreement (by all readers, expert and young observers and comparison of the two protocols) was then statistically analyzed. According to Cohen's criteria, inter-observer agreement among the four readers and between experts and residents was good for the detection of bone lesions and extra-medullary extension, and for the evaluation of risk of collapse and cortical integrity. There was good agreement when comparing the two protocols. A greater variability was found for the evaluation of hyperattenuating lesions and the presence of fractures. WB-LDCT represents a reproducible and reliable technique that is helpful for defining bone disease in MM patients, with partial influence of readers' experience. (orig.)

  18. Non-invasive evaluation of facial crestal bone with ultrasonography

    Science.gov (United States)

    Sinjab, Khaled; Chung, Ming-Pang; Chiang, Yi-Chen; Wang, Hom-Lay; Giannobile, William V.; Kripfgans, Oliver D.

    2017-01-01

    Purpose Facial crestal bone level and dimension determine function and esthetics of dentition and dental implants. We have previously demonstrated that ultrasound can identify bony and soft tissue structures in the oral cavity. The aim of this study is to evaluate the accuracy of using ultrasound to measure facial crestal bone level and thickness. Materials and methods A commercially available medical ultrasound scanner, paired with a 14 MHz imaging probe was used to scan dental and periodontal tissues at the mid-facial site of each tooth on 6 fresh cadavers. The alveolar crest level in relation to the cemento-enamel junction and its thickness on ultrasound images were measured and compared to those on cone-beam computed tomography (CBCT) scans and/or direct measurements on a total of 144 teeth. Results The mean crestal bone level measured by means of ultrasound, CBCT and direct measures was 2.66 ± 0.86 mm, 2.51 ± 0.82 mm, and 2.71 ± 1.04 mm, respectively. The mean crestal bone thickness was 0.71 ± 0.44 mm and 0.74 ± 0.34 mm, measured by means of ultrasound and CBCT, respectively. The correlations of the ultrasound readings to the other two methods were between 0.78 and 0.88. The mean absolute differences in crestal bone height and thickness between ultrasound and CBCT were 0.09 mm (-1.20 to 1.00 mm, p = 0.06) and 0.03 mm (-0.48 to 0.54 mm, p = 0.03), respectively. Conclusion Ultrasound was as accurate in determining alveolar bone level and its thickness as CBCT and direct measurements. Clinical trials will be required to further validate this non-ionizing and non-invasive method for determining facial crestal bone position and dimension. PMID:28178323

  19. Fast volumetric imaging of bound and pore water in cortical bone using three-dimensional ultrashort-TE (UTE) and inversion recovery UTE sequences.

    Science.gov (United States)

    Chen, Jun; Carl, Michael; Ma, Yajun; Shao, Hongda; Lu, Xing; Chen, Bimin; Chang, Eric Y; Wu, Zhihong; Du, Jiang

    2016-10-01

    We report the three-dimensional ultrashort-TE (3D UTE) and adiabatic inversion recovery UTE (IR-UTE) sequences employing a radial trajectory with conical view ordering for bi-component T2 * analysis of bound water (T2 *(BW) ) and pore water (T2 *(PW) ) in cortical bone. An interleaved dual-echo 3D UTE acquisition scheme was developed for fast bi-component analysis of bound and pore water in cortical bone. A 3D IR-UTE acquisition scheme employing multiple spokes per IR was developed for bound water imaging. Two-dimensional UTE (2D UTE) and IR-UTE sequences were employed for comparison. The sequences were applied to bovine bone samples (n = 6) and volunteers (n = 6) using a 3-T scanner. Bi-component fitting of 3D UTE images of bovine samples showed a mean T2 *(BW) of 0.26 ± 0.04 ms and T2 *(PW) of 4.16 ± 0.35 ms, with fractions of 21.5 ± 3.6% and 78.5 ± 3.6%, respectively. The 3D IR-UTE signal showed a single-component decay with a mean T2 *(BW) of 0.29 ± 0.05 ms, suggesting selective imaging of bound water. Similar results were achieved with the 2D UTE and IR-UTE sequences. Bi-component fitting of 3D UTE images of the tibial midshafts of healthy volunteers showed a mean T2 *(BW) of 0.32 ± 0.08 ms and T2 *(PW) of 5.78 ± 1.24 ms, with fractions of 34.2 ± 7.4% and 65.8 ± 7.4%, respectively. Single-component fitting of 3D IR-UTE images showed a mean T2 *(BW) of 0.35 ± 0.09 ms. The 3D UTE and 3D IR-UTE techniques allow fast volumetric mapping of bound and pore water in cortical bone. Copyright © 2016 John Wiley & Sons, Ltd.

  20. 人工耳蜗植入术中自体乳突皮质骨重建乳突腔骨质缺损%Using Autologous Mastoid Cortical Bone during Cochlear Implantation

    Institute of Scientific and Technical Information of China (English)

    刘丛利; 孙家强; 侯晓燕; 陈建文; 孙敬武

    2015-01-01

    目的:探讨在成人人工耳蜗植入术中,应用自体乳突区皮质骨回放覆盖乳突切开后骨质缺损的临床效果。方法以58例行人工耳蜗植入的成人极重度感音神经性聋患者为研究对象(修复组),术中均采用切除的自体乳突区皮质骨片回放重建乳突切开后骨缺损的手术方式,术后观察患者耳后伤口痊愈情况、有无并发症;于术后1月开机时及术后3、6月检测助听听阈,并与同期未行自体乳突皮质骨重建乳突腔骨质缺损的同类患者(对照组)比较。结果修复组术后无一例出现耳后皮肤凹陷,均没有发生创面感染、急慢性中耳炎及颅内并发症,回放的皮质骨片愈合良好;术后复查所有患者耳蜗植入体无移位,术后1月开机时患者的平均助听听阈较术前提高约70 dB(P<0.05),术后1、3、6月平均助听听阈与对照组差异无统计学意义(均为 P>0.05),效果良好。结论在成人人工耳蜗植入手术中,应用自体乳突区皮质骨重建乳突腔皮质骨缺损能够避免耳后的凹陷,保证乳突的通气,有利于植入体的稳定性,且术后助听效果良好。%Objective To assessment the effect of autologous mastoid cortical bone to cover the mastoidetomy defect via transmastoid and posterior tympanotomy approach surgical technique during cochlear implantation in a ‐dults .Methods A total of 58 adults patients with profound sensorineural hearing loss accepted cochlear implantation from January 2010 and June 2014 ,which were using autologous mastoid cortical bone to cover the mastoidetomy de‐fect via transmastoid and posterior tympanotomy approach surgical technique .By observing postoperation complica‐tion the effect of surgery was evaluated .ABR were obtained for each patients at first ,third and sixth month after op‐eration .The patients which were not using autologous mastoid cortical bone to cover the mastoidetomy

  1. Axial-Plane Biomechanical Evaluation of 2 Suspensory Cortical Button Fixation Constructs for Acromioclavicular Joint Reconstruction

    Science.gov (United States)

    Struhl, Steven; Wolfson, Theodore S.; Kummer, Frederick

    2016-01-01

    Background: Although numerous suture-button fixation techniques for acromioclavicular (AC) joint reconstruction have been validated with biomechanical testing in the superior direction, clinical reports continue to demonstrate high rates of construct slippage and breakage. Purpose: To compare the stability of a novel closed-loop double Endobutton construct with a commercially available cortical button system in both the axial and superior directions. Study Design: Controlled laboratory study. Methods: Six matched pairs of fresh-frozen cadaveric upper extremities were anatomically dissected and prepared to simulate a complete AC joint dislocation. One side of each pair was reconstructed with the double Endobutton (DE) construct and other side with the dog bone button (DB) construct. The specimens were then tested using a materials testing machine, determining initial superior and axial displacements with a preload, and then cyclically loaded in the axial direction with 70 N for 5000 cycles. Displacement was again measured with the same preloads at fixed cycle intervals. The specimens were then loaded superiorly to failure. Results: At 5000 cycles, the mean axial displacement was 1.7 mm for the DB group and 1.2 mm for the DE group (P = .19), and the mean superior displacement was 1.1 mm for the DB group and 0.7 mm for the DE group (P = .32). Load at failure was similar (558 N for DE, 552 N for DB; P = .96). There was no statistically significant difference in the modes of failure. Conclusion: Biomechanical testing of both constructs showed similar fixation stability after cyclical axial loading and similar loads to failure. Clinical Relevance: The strength of both constructs after cyclical loading in the axial plane and load-to-failure testing in the superior plane validate their continued clinical use for achieving stability in AC joint reconstruction procedures. PMID:28210644

  2. A longitudinal HR‐pQCT study of alendronate treatment in postmenopausal women with low bone density: Relations among density, cortical and trabecular microarchitecture, biomechanics, and bone turnover

    National Research Council Canada - National Science Library

    Burghardt, Andrew J; Kazakia, Galateia J; Sode, Miki; de Papp, Anne E; Link, Thomas M; Majumdar, Sharmila

    2010-01-01

    The goal of this study was to characterize longitudinal changes in bone microarchitecture and function in women treated with an established antifracture therapeutic. In this double‐blind, placebo...

  3. Evaluation of the Neuroactivity of ToxCast Compounds Using Multi-well Microelectrode Array Recordings in Primary Cortical Neurons

    Science.gov (United States)

    Evaluation of the Neuroactivity of ToxCast Compounds Using Multi-well Microelectrode Array Recordings in Primary Cortical Neurons P Valdivia1, M Martin2, WR LeFew3, D Hall3, J Ross1, K Houck2 and TJ Shafer3 1Axion Biosystems, Atlanta GA and 2NCCT, 3ISTD, NHEERL, ORD, US EPA, RT...

  4. Bone dynamic study. Evaluation for factor analysis of hip joint

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Kotaro; Toyama, Hinako; Ishikawa, Nobuyoshi; Hatakeyama, Rokuro; Akisada, Masayoshi; Miyagawa, Shunpei

    1989-02-01

    Factor analysis was applied to dynamic study of Tc-99m MDP for the evaluation of hip joint disorders. Fifteen patients were examined; eight were normal, six was osteoarthritis in which one accompanied synovitis was included, and one was aseptic necrosis on the head of the femur. In normals, according to the Tc-99m MDP kinetics, three factor images and time-activity curves were obtained which were named as blood vessel, soft tissue, and bone factor images and curves. In the patient with osteoarthritis, increased accumulation of the hip joint was shown in bone factor image only. But in one patient, who took osteoarthritis with synovitis, marked accumulations of the Tc-99m MDP appeared not only on the bone factor image but also on the soft tissue. Operation revealed thickening synovial tissue around the hip joint, caused by inflammatory process. In follow-up studies of the patient with aseptic necrosis on the head of the left femur, exessive accumulations, which were seemed in his left hip joint on both bone and soft tissue factor images at first, were decreased respondently to the treatment of this lesion. In conclusion, the factor analysis was useful for differential diagnosis of the hip joint disorders and observation of the clinical course of the hip joint disorders.

  5. Influence of short-term fixation with mixed formalin or ethanol solution on the mechanical properties of human cortical bone

    OpenAIRE

    Mick E.; Steinke H.; Wolfskämpf T.; Wieding J.; Hammer N.; Schulze M.; Souffrant R.; Bader R.

    2015-01-01

    Bone specimens obtained for biomechanical experiments are fresh-frozen for storage to slow down tissue degradation and autolysis in long-term storage. Alternatively, due to infectious risks related to the fresh tissues, fixative agents are commonly used. However, fixatives will likely change the mechanical properties of bone. Existing studies on this issue gave controversial results that are hardly comparable due to a variety of measurement approaches. For this reason, the influence of ethano...

  6. Controlled evaluation of a neurofeedback training of slow cortical potentials in children with Attention Deficit/Hyperactivity Disorder (ADHD

    Directory of Open Access Journals (Sweden)

    Heinrich Hartmut

    2007-07-01

    Full Text Available Abstract Background Although several promising studies on neurofeedback training in Attention Deficit/Hyperactivity Disorder (ADHD have been performed in recent years, the specificity of positive treatment effects continues to be challenged. Methods To evaluate the specificity of a neurofeedback training of slow cortical potentials, a twofold strategy was pursued: First, the efficacy of neurofeedback training was compared to a group training program for children with ADHD. Secondly, the extent of improvements observed in the neurofeedback group in relation to successful regulation of cortical activation was examined. Parents and teachers rated children's behaviour and executive functions before and after treatment. In addition, children underwent neuropsychological testing before and after training. Results According to parents' and teachers' ratings, children of the neurofeedback training group improved more than children who had participated in a group therapy program, particularly in attention and cognition related domains. On neuropsychological measures children of both groups showed similar improvements. However, only about half of the neurofeedback group learned to regulate cortical activation during a transfer condition without direct feedback. Behavioural improvements of this subgroup were moderately related to neurofeedback training performance, whereas effective parental support accounted better for some advantages of neurofeedback training compared to group therapy according to parents' and teachers' ratings. Conclusion There is a specific training effect of neurofeedback of slow cortical potentials due to enhanced cortical control. However, non-specific factors, such as parental support, may also contribute to the positive behavioural effects induced by the neurofeedback training.

  7. Probing physical and chemical changes in cortical bone due to osteoporosis and type 2 diabetes by solid-state NMR

    Science.gov (United States)

    Zhou, Donghua; Taylor, Amanda; Rendina, Beth; Smith, Brenda; Department of Physics Collaboration; Department of Nutritional Sciences Collaboration

    2013-03-01

    Approximately 1.5 million fractures occur each year in the U.S. due to osteoporosis, which is characterized by decreased bone mineral density and deterioration of bone micro-architecture. On the other hand, type 2 diabetes also significantly increases fracture risks, despite having a normal or even higher bone mineral density. Solid-state NMR has been applied to bone tissues from normal and disease-inflicted mouse models to study structural and chemical dynamics as the disease progresses. Proton relaxation experiments were performed to measure water populations in the bone matrix and pores. Collagen-bound water has strong influence on bone resilience, while water content in the pores reveals amount and size of pores from micro- to millimeter range. Other biochemical and atomic-scale structural alterations in the mineral and organic phases and their interface were investigated by proton, phosphorus, and carbon NMR spectroscopy. Experiments were designed to individually detect different types of phosphorus environments: near the mineral surface, similar to hydroxyapatite, and deficient of hydrogens due to substitution of the hydroxyl group by other ions. A new method was also developed for accurate quantification of each phosphorus species. The authors appreciate financial support for this project from the College of Human Sciences and the College of Arts and Sciences, Oklahoma State University.

  8. Evaluation of the innate and adaptive immunity in type I and type II focal cortical dysplasias

    NARCIS (Netherlands)

    Lyer, A.; Zurolo, E.; Spliet, W.G.M.; van Rijen, P.C.; Baayen, J.C.; Gorter, J.A.; Aronica, E.

    2010-01-01

    Purpose:  Induction of inflammatory pathways has been reported in epileptic patients with focal malformations of cortical development. In the present study we examined the innate and adaptive immune responses in focal cortical dysplasia (FCD) with different histopathologic and pathogenetic features.

  9. Orchidectomy-induced alterations in volumetric bone density, cortical porosity and strength of femur are attenuated by dietary conjugated linoleic acid in aged guinea pigs.

    Science.gov (United States)

    DeGuire, Jason R; Mak, Ivy L; Lavery, Paula; Agellon, Sherry; Wykes, Linda J; Weiler, Hope A

    2015-04-01

    Age-related osteoporosis and sarcopenia are ascribed in part to reductions in anabolic hormones. Dietary conjugated linoleic acid (CLA) improves lean and bone mass, but its impact during androgen deficiency is not known. This study tested if CLA would attenuate the effects of orchidectomy (ORX)-induced losses of bone and lean tissue. Male guinea pigs (n=40; 70-72 weeks), were randomized into four groups: (1) SHAM+Control diet, (2) SHAM+CLA diet, (3) ORX+Control diet, (4) ORX+CLA diet. Baseline blood sampling and dual-energy X-ray absorptiometry (DXA) scans were conducted, followed by surgery 4 days later with the test diets started 7 days after baseline sampling. Serial blood sampling and DXA scans were repeated 2, 4, 8 and 16 weeks on the test diets. Body composition and areal BMD (aBMD) of whole body, lumbar spine, femur and tibia were measured using DXA. At week 16, muscle protein fractional synthesis rate (FSR), volumetric BMD (vBMD), microarchitecture and bone strength were assessed. Body weight declined after SHAM and ORX surgery, with slower recovery in the ORX group. Dietary CLA did not affect weight or lean mass, but attenuated gains in fat mass. Lean mass was stable in SHAM and reduced in ORX by 2 weeks with whole body and femur bone mineral content (BMC) reduced by 4 weeks; CLA did not alter BMC. By week 16 ORX groups had lower free testosterone and myofibrillar FSR, yet higher cortisol, osteocalcin and ionized calcium with no alterations due to CLA. ORX+Control had higher prostaglandin E2 (PGE2) and total alkaline phosphatase compared to SHAM+Control whereas ORX+CLA were not different from SHAM groups. Femur metaphyseal vBMD was reduced in ORX+CTRL with the reduction attenuated by CLA. Femur cortical thickness (Ct.Th.) and biomechanical strength were reduced and cortical porosity (Ct.Po.) elevated by ORX and attenuated by CLA. This androgen deficient model with a sarcopenic-osteoporotic phenotype similar to aging men responded to dietary CLA with

  10. Deciphering seasonal variations in the diet and drinking water of modern White-Tailed deer by in situ analysis of osteons in cortical bone

    Science.gov (United States)

    Larson, T. E.; Longstaffe, F. J.

    2007-12-01

    In situ carbon and oxygen isotope values for bioapatite were obtained from longitudinal slices of cortical bone from modern domesticated sheep and free-range White-Tailed deer. The analyses were obtained using an IR-laser coupled to a GC-IRMS interface. Ablation pits averaged 200 × 50 μm, making it possible to sample individual or small bundles of osteons. Cortical bone is remodeled along osteons throughout a mammal's life. Therefore, data at this scale can record seasonal variations in diet and drinking water during the adult stages of a mammal, whereas teeth provide may provide information about the juvenile years of a mammal. Average δ18O and δ13C values for the sheep from southwestern Ontario, Canada, were 14.0 and -16.1‰, respectively. No trend was observed in the isotopic composition of the sheep's osteons, consistent with its constant diet and water supply. The δ18O (14.2 to 16.6‰) and δ13C (-19.2 to -15.6‰) values of osteons from White-Tailed deer from nearby Pinery Provincial Park, however, varied systematically and were negatively correlated. Oxygen isotope values of the osteons correlated well with changes in the δ18O values of the main water source for these deer: winter average, -10.7‰; summer average, -8.6‰. The variation in δ13C values of the osteons reflects changes in diet; summer diet consisted mainly of leafy C3 vegetation (-28.4‰), whereas winter diet comprised bark (-25.6‰), C4 grasses (δ13C, -12.7‰), and corn stalks and husks (-11.3‰).

  11. Effects of repetitive loading on the growth-induced changes in bone mass and cortical bone geometry: a 12-month study in pre/peri- and postmenarcheal tennis players.

    Science.gov (United States)

    Ducher, Gaele; Bass, Shona L; Saxon, Leanne; Daly, Robin M

    2011-06-01

    Pre- and early puberty may be the most opportune time to strengthen the female skeleton, but there are few longitudinal data to support this claim. Competitive female premenarcheal (pre/peri, n = 13) and postmenarcheal (post, n = 32) tennis players aged 10 to 17 years were followed over 12 months. The osteogenic response to loading was studied by comparing the playing and nonplaying humeri for dual-energy X-ray absorptiometry (DXA) bone mineral content (BMC) and magnetic resonance imaging (MRI) total bone area (ToA), medullary area (MedA), cortical area (CoA), and muscle area (MCSA) at the humerus. Over 12 months, growth-induced gains (nonplaying arm) in BMC, ToA, and CoA were greater in pre/peri (10% to 19%, p < .001) than in post (3% to 5%, p < .05 to .001) players. At baseline, BMC, ToA, CoA, and MCSA were 8% to 18% greater in the playing versus nonplaying arms in pre/peri and post players (all p < .001); MedA was smaller in the playing versus nonplaying arms in post only players (p < .05). When comparing the annual gains in the playing arm relative to changes in the nonplaying arm, the increases in ToA and CoA were greater in pre/peri than post players (all p < .05). The smaller the side-to-side differences in BMC and CoA at baseline, the larger the exercise benefits at 12 months (r = -0.39 to -0.48, p < .01). The exercise-induced change in MCSA was predictive of the exercise benefits in BMC in pre/peri players only (p < .05). In conclusion, both pre/peri- and postmenarcheal tennis players showed significant exercise-induced skeletal benefits within a year, with greater benefits in cortical bone geometry in pre/perimenarcheal girls.

  12. Histological evaluation of the influence of magnetic field application in autogenous bone grafts in rats

    Directory of Open Access Journals (Sweden)

    Ponzoni Deise

    2009-01-01

    Full Text Available Abstract Background Bone grafts are widely used in oral and maxillofacial reconstruction. The influence of electromagnetic fields and magnets on the endogenous stimulation of target tissues has been investigated. This work aimed to assess the quality of bone healing in surgical cavities filled with autogenous bone grafts, under the influence of a permanent magnetic field produced by in vivo buried devices. Methods Metal devices consisting of commercially pure martensitic stainless steel washers and titanium screws were employed. Thirty male Wistar rats were divided into 3 experimental and 3 control groups. A surgical bone cavity was produced on the right femur, and a bone graft was collected and placed in each hole. Two metallic washers, magnetized in the experimental group but not in the control group, were attached on the borders of the cavity. Results The animals were sacrificed on postoperative days 15, 45 and 60. The histological analysis of control and experimental samples showed adequate integration of the bone grafts, with intense bone neoformation. On days 45 and 60, a continued influence of the magnetic field on the surgical cavity and on the bone graft was observed in samples from the experimental group. Conclusion The results showed intense bone neoformation in the experimental group as compared to control animals. The intense extra-cortical bone neoformation observed suggests that the osteoconductor condition of the graft may be more susceptible to stimulation, when submitted to a magnetic field.

  13. Toxicity evaluation of new agricultural fungicides in primary cultured cortical neurons.

    Science.gov (United States)

    Regueiro, Jorge; Olguín, Nair; Simal-Gándara, Jesús; Suñol, Cristina

    2015-07-01

    Fungicides are crucial for food protection as well as for the production of crops of suitable quality and quantity to provide a viable economic return. Like other pesticides, fungicides are widely sprayed on agricultural land, especially in wine-growing areas, from where they can move-off after application. Furthermore, residues of these agrochemicals can remain on crops after harvest and even after some food processing operations, being a major exposure pathway. Although a relatively low toxicity has been claimed for this kind of compounds, information about their neurotoxicity is still scarce. In the present study, nine fungicides recently approved for agricultural uses in the EU - ametoctradin, boscalid, cyazofamid, dimethomorph, fenhexamid, kresoxim-methyl, mepanipyrim, metrafenone and pyraclostrobin - have been evaluated for their toxicity in primary cultured mouse cortical neurons. Exposure to 0.1-100µM for 7 days in vitro resulted in a dose-dependent toxicity in the MTT cell viability assay. Strobilurin fungicides kresoxim-methyl (KR) and pyraclostrobin (PY) were the most neurotoxic compounds (lethal concentration 50 were in the low micromolar and nanomolar levels, respectively) causing a rapid raise in intracellular calcium [Ca(2+)]i and strong depolarization of mitochondrial membrane potential. KR- and PY-induced cell death was reversed by the calcium channels blockers MK-801 and verapamil, suggesting that calcium entry through NMDA receptors and voltage-operated calcium channels are involved in KR- and PY-induced neurotoxicity. These results highlight the need for further evaluation of their neurotoxic effects in vivo.

  14. Bone structural changes after gastric bypass surgery evaluated by HR-pQCT

    DEFF Research Database (Denmark)

    Shanbhogue, Vikram Vinod; Støving, René Klinkby; Frederiksen, Katrine Diemer

    2017-01-01

    maximal at month 12 and stabilized from month 12 to 24. CONCLUSIONS: Despite weight stabilization and maintenance of metabolic parameters, bone loss and deterioration in bone strength continued and were substantial in the second year. The clinical importance of these changes in terms of increased risk......Objective, design and methods: Roux-en-Y gastric bypass (RYGB) has proved successful in attaining sustained weight loss but may lead to metabolic bone disease. To assess impact on bone mass and structure, we measured areal bone mineral density at the hip and spine by dual-energy x...... measured at the same time points. RESULTS: After a 24.1% mean weight loss from baseline to month 12 (pweight plateaued from month 12 to 24 (-0.9%, p=0.50). However, cortical and trabecular vBMD and microarchitecture deteriorated through the 24 months, such that there was a 5% and 7% reduction...

  15. Mechanically-induced osteogenesis in the cortical bone of pre- to peripubertal stage and peri- to postpubertal stage mice

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    Plochocki Jeffrey H

    2009-06-01

    Full Text Available Abstract Background Exercise during postnatal development plays a key role in determining adult bone mass and reducing the risk of fracture and osteoporosis later in life. However, the relationship between mechanically-induced osteogenesis and age is unclear. Elevated levels of estrogen during puberty may inhibit periosteal bone formation. Thus, magnitudes of mechanically-induced osteogenesis may be vary with pubertal state. Methods The present study uses a murine model to examine age-related changes in bone formation at the femoral midshaft with voluntary exercise. Pre- to peripubertal mice aged 3 weeks and peri- to postpubertal mice aged 7 weeks were randomly divided into sedentary and exercised groups and subjected to histomorphometric comparison after 4 weeks of treatment. Results Results of the experiment indicate that exercise significantly increased osteogenesis on the periosteal and endocortical surface of the mice in the older age group (P P Conclusion These findings suggest that the amount and location of mechanically-induced osteogenesis differs by age during skeletal development. Late adolescence may be the optimal time to accrue bone mass and maximize bone strength.

  16. Evaluation of injectable silica-embedded nanohydroxyapatite bone substitute in a rat tibia defect model

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    Xu W

    2011-08-01

    Full Text Available Weiguo Xu1, Cornelia Ganz2, Ulf Weber2, Martin Adam2, Gerd Holzhüter2, Daniel Wolter3, Bernhard Frerich3, Brigitte Vollmar1, Thomas Gerber21Institute for Experimental Surgery, 2Institute of Physics, 3Department of Oral, Maxillofacial and Plastic Surgery, University of Rostock, Rostock, GermanyAbstract: In clinical practice, vertebral compression fractures occur after trauma and osteoporosis. Kyphoplasty is a minimally invasive procedure using bone filler material for the treatment of such fractures. A full synthetic injectable bone substitute (SIBS was manufactured by means of spray drying. The aim of this study was to characterize the SIBS and to analyze the remodelling process during degradation of the biomaterial and new bone formation after implantation. SIBS is an aqueous suspension of donut-like microparticles. These microparticles consist of nanocrystallites of synthetic hydroxyapatite embedded in amorphous silica gel. After implantation of SIBS in a proximal tibial diaphyseal defect in 52 rats, grafts were harvested for subsequent analysis on different days. Newly formed bone originating from endosteum was observed on day 6. Hematomas in the medullary space and cortical wounds disappeared on day 12. The wound region was completely replaced by a composite of newly formed cancellous bone, extracellular matrix, and SIBS. At day 63 the cortical defect was fully healed by bone, while newly formed bone in the medullary space almost disappeared and was replaced with bone marrow. In conclusion, SIBS demonstrated a unique structure with osteoinductive and bioresorbable properties, which induced fast bone regeneration. Therefore, a clinical application of SIBS for kyphoplasty is promising.Keywords: bone remodelling, electron microscopy, histomorphometry, nanotechnology, tissue engineering

  17. Effect of rotopositioning on the growth and maturation of mandibular bone in immobilized Rhesus monkeys

    Science.gov (United States)

    Simmons, D. J.; Parvin, C.; Smith, K. C.; France, P.; Kazarian, L.

    1986-01-01

    The rates of bone formation and mineralization in the mandibular cortex of juvenile Rhesus monkeys exposed to immobilization/rotopositioning are evaluated. The monkeys were restrained in a supine position and rotated 90 deg every 30 minutes through a full 360 deg for 14 days. The microscopic distribution of mineral densities in osteonal bone and the porosity of cortical bone are studied using microradiographs, and osteon closure rates are assessed using tetracycline labeling; normal distributions of osteons of different mineral density and cortical bone porosity values are observed. It is concluded that 14 days of immobilization/rotopositioning did not cause abnormal changes in osteon mineralization, cortical porosity, and osteon closure rates.

  18. EVALUATION OF RADIONUCLIDE BONE IMAGING FOR SKELETAL DISEASE

    Institute of Scientific and Technical Information of China (English)

    林奋; 袁济民

    1993-01-01

    Whole body bone scan imaging of 99mTc-MDP was performed in 80 casesfrom Sept 1991 to Feb 1992. Among them 20 patients showed negtive bone imaging and56 patients showed positive bone imaging. There were false-positive bone imaging in 4 pa-tients. Bone scan imaging has been regarded as a useful method in the early diagnosis ofshelatal disease, especially in old patients with bone metastasis. But the final confirmationof malignancy should be still cautious.

  19. Early postoperative bone scintigraphy in the evaluation of microvascular bone grafts in head and neck reconstruction

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    Poissonnet Gilles

    2007-04-01

    Full Text Available Abstract Background Bone scintigraphy was performed to monitor anastomotic patency and bone viability. Methods In this retrospective study, bone scans were carried out during the first three postoperative days in a series of 60 patients who underwent microvascular bone grafting for reconstruction of the mandible or maxilla. Results In our series, early bone scans detected a compromised vascular supply to the bone with high accuracy (p Conclusion When performing bone scintigraphy during the first three postoperative days, it not only helps to detect complications with high accuracy, as described in earlier studies, but it is also an additional reliable monitoring tool to decide whether or not microvascular revision surgery should be performed. Bone scans were especially useful in buried free flaps where early postoperative monitoring depended exclusively on scans. According to our experience, we recommend bone scans as soon as possible after surgery and immediately in cases suspicious of vascularized bone graft failure.

  20. The effect of muscle contusion on cortical bone and muscle perfusion following reamed, intramedullary nailing: a novel canine tibia fracture model

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    Zdero Rad

    2010-11-01

    Full Text Available Abstract Background Management of tibial fractures associated with soft tissue injury remains controversial. Previous studies have assessed perfusion of the fractured tibia and surrounding soft tissues in the setting of a normal soft tissue envelope. The purpose of this study was to determine the effects of muscle contusion on blood flow to the tibial cortex and muscle during reamed, intramedullary nailing of a tibial fracture. Methods Eleven adult canines were distributed into two groups, Contusion or No-Contusion. The left tibia of each canine underwent segmental osteotomy followed by limited reaming and locked intramedullary nailing. Six of the 11 canines had the anterior muscle compartment contused in a standardized fashion. Laser doppler flowmetry was used to measure cortical bone and muscle perfusion during the index procedure and at 11 weeks post-operatively. Results Following a standardized contusion, muscle perfusion in the Contusion group was higher compared to the No-Contusion group at post-osteotomy and post-reaming (p 0.05. There was a sustained decrease in overall bone perfusion in the Contusion group at 11 weeks, compared to the No-Contusion group (p Conclusions Injury to the soft tissue envelope may have some deleterious effects on intraosseous circulation. This could have some influence on the fixation method for tibia fractures linked with significant soft tissue injury.

  1. [Advancement in methods of evaluation on bone fracture healing and its application in forensic medicine].

    Science.gov (United States)

    Li, Yu-fei

    2011-02-01

    It is frequently encountered to identify the time of bone fracture in forensic medicine. Hence it is important to develop the methods for evaluating the time of bone fracture. This article reviews the applications and values of the methods such as ultrasonic evaluation, impulse measurement, digital imaging technology and bone mineral density testing technology, etc. It is proposed that to use these methods jointly may provide more scientific evidence in determine the time of bone fracture.

  2. [Development of a Novel Body Phantom with Bone Equivalent Density for Evaluation of Bone SPECT].

    Science.gov (United States)

    Ichikawa, Hajime; Miwa, Kenta; Matsutomo, Norikazu; Watanabe, Yoichi; Kato, Toyohiro; Shimada, Hideki

    2015-12-01

    We developed a custom-designed phantom for bone single photon emission computed tomography (SPECT)-specific radioactivity distribution and linear attenuation coefficient. The aim of this study was to evaluate the accuracy of the phantom. The lumbar phantom consisted of the trunk of a body phantom (background) containing a cylinder (vertebral body), a sphere (tumor), and a T-shaped container (processus). The vertebral body, tumor, and processus phantoms contained a K(2)HPO(4) solution of bone equivalent density and 50, 300 and 50 kBq/mL of (99m)Tc, respectively. The body phantom contained 8 kBq/mL of (99m)Tc solution. SPECT images were acquired using low-energy high-resolution collimation, a 128 × 128 matrix and 120 projections over 360° with a dwell time of 15 sec/view × 4 times. Thereafter, CT images were acquired at 130 kV and 70 ref mAs using adaptive dose modulation. The SPECT data were reconstructed with ordered subset expectation maximization with three-dimensional, scatter, and CT-based attenuation correction. Count ratio, linear attenuation coefficient (LAC), and full-width at half-maximum (FWHM) were measured. Count ratios between the background, the vertebral body, and the tumor in SPECT images were 463.8: 2888.0: 15150.3 (1: 6.23: 32.7). The LAC of the background and vertebral body in the CT-derived attenuation map were 0.155 cm⁻¹ and 0.284 cm⁻¹, respectively, and the FWHM measured from the processus was 15.27 mm. The precise counts and LAC indicated that the phantom was accurate and could serve as a tool for evaluating acquisition, reconstruction parameters, and quantitation in bone SPECT images.

  3. Evaluation of bone surrogates for indirect and direct ballistic fractures.

    Science.gov (United States)

    Bir, Cynthia; Andrecovich, Chris; DeMaio, Marlene; Dougherty, Paul J

    2016-04-01

    The mechanism of injury for fractures to long bones has been studied for both direct ballistic loading as well as indirect. However, the majority of these studies have been conducted on both post-mortem human subjects (PMHS) and animal surrogates which have constraints in terms of storage, preparation and testing. The identification of a validated bone surrogate for use in forensic, medical and engineering testing would provide the ability to investigate ballistic loading without these constraints. Two specific bone surrogates, Sawbones and Synbone, were evaluated in comparison to PMHS for both direct and indirect ballistic loading. For the direct loading, the mean velocity to produce fracture was 121 ± 19 m/s for the PMHS, which was statistically different from the Sawbones (140 ± 7 m/s) and Synbone (146 ± 3 m/s). The average distance to fracture in the indirect loading was .70 cm for the PMHS. The Synbone had a statistically similar average distance to fracture (.61 cm, p=0.54) however the Sawbones average distance to fracture was statistically different (.41 cm, pballistic testing was not identified and future work is warranted.

  4. Anterior Reduction, Discectomy, and Three Cortical Iliac Bone Grafting With Instrumentation to Treat A Huge Tear Drop Fracture of the Axis: A Case Report and Literature Review.

    Science.gov (United States)

    Ma, Litai; Yang, Yi; Gong, Quan; Ding, Chen; Liu, Hao; Hong, Ying

    2016-04-01

    Fractures of the axis body have been little reported and treatment strategies remain controversial and individualized. Not more than 10 cases of huge tear drop fracture of the axis (HTDFA) have been reported in previous studies and the treatment method varies from conservative treatment to an anterior, or posterior, approach surgery. Considering the sparse knowledge of HTDFA, we present a special case report to share our experience and to explore the safety and effectiveness of anterior reduction and fusion to treat HTDFA. A 24-year-old man was referred to our department; he presented with neck pain lasting for 12 h since being involved in a roll-over motor vehicle accident. His neck movement was limited but there was no neurological compromise. Physical examination of the patient showed myodynamia of four limbs Grade 5, Hoffmann sign (-), and Babinski sign (-). Three-dimensional reconstruction computed tomography (CT) confirmed a huge tear drop fracture of the anterior-inferior corner of the axis and discontinuity of the cortex of the axis. After discussion with the spinal surgeon team in the department and an effective conversation with the patient, surgery involving anterior reduction, discectomy, and three cortical iliac bone grafts with instrumentation after transnasal induction of general anesthesia was performed. The patient was instructed to wear a cervical collar until he returned to our department for a follow-up examination some 3 months after surgery. The 3-month postoperative x-ray and CT scan showed a good position of the implant and bony fusion at the C2/3 segment. Anterior reduction, discectomy, and three cortical iliac bone grafts with instrumentation to treat HTDFA are effective, safe, and simple. Of course, longer follow-up duration and more cases are warranted to verify this procedure. Anterior reduction, discectomy, and bone grafting with instrumentation are warranted for most HTDFA cases. However, if HTDFA incorporates other complex

  5. Anterior Reduction, Discectomy, and Three Cortical Iliac Bone Grafting With Instrumentation to Treat A Huge Tear Drop Fracture of the Axis

    Science.gov (United States)

    Ma, Litai; Yang, Yi; Gong, Quan; Ding, Chen; Liu, Hao; Hong, Ying

    2016-01-01

    Abstract Fractures of the axis body have been little reported and treatment strategies remain controversial and individualized. Not more than 10 cases of huge tear drop fracture of the axis (HTDFA) have been reported in previous studies and the treatment method varies from conservative treatment to an anterior, or posterior, approach surgery. Considering the sparse knowledge of HTDFA, we present a special case report to share our experience and to explore the safety and effectiveness of anterior reduction and fusion to treat HTDFA. A 24-year-old man was referred to our department; he presented with neck pain lasting for 12 h since being involved in a roll-over motor vehicle accident. His neck movement was limited but there was no neurological compromise. Physical examination of the patient showed myodynamia of four limbs Grade 5, Hoffmann sign (–), and Babinski sign (–). Three-dimensional reconstruction computed tomography (CT) confirmed a huge tear drop fracture of the anterior–inferior corner of the axis and discontinuity of the cortex of the axis. After discussion with the spinal surgeon team in the department and an effective conversation with the patient, surgery involving anterior reduction, discectomy, and three cortical iliac bone grafts with instrumentation after transnasal induction of general anesthesia was performed. The patient was instructed to wear a cervical collar until he returned to our department for a follow-up examination some 3 months after surgery. The 3-month postoperative x-ray and CT scan showed a good position of the implant and bony fusion at the C2/3 segment. Anterior reduction, discectomy, and three cortical iliac bone grafts with instrumentation to treat HTDFA are effective, safe, and simple. Of course, longer follow-up duration and more cases are warranted to verify this procedure. Anterior reduction, discectomy, and bone grafting with instrumentation are warranted for most HTDFA cases. However, if HTDFA incorporates other

  6. Magnification bone scan of knees for knee pain evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Myoung Hoon; Park, Chan H.; Yoon, Seok Nam; Hwang, Kyung Hoon [College of Medicine, Ajou Univ., Suwon (Korea, Republic of)

    2001-07-01

    Knee pain is one of the common complaints of patients seen in our orthopedic clinic. Routine anterior and posterior views of whole body bone scan (WBBS) is often not sufficient in the evaluation of these patients. An ideal bone scan using pinhole collimator or single photon emission tomography (SPECT), however, is impractical and time consuming in busy nuclear medicine department with limited resources. Therefore, the aim of the study is to assess limited bone scan of knees with magnification (LNSKM) for knee pain evaluation. Technical aspect of LBSKM and diagnostic efficacy are discussed on this poster. Adult patients with knee pain were reffered for LBSKM from an orthopedic surgen specializing knees. Four hundred fifteen LBSKMs were performed since 1999. patients were given 740 MBq (20mCi) Tc-99m MDP intravenously and 3 hours later LBSKM was performed using a low energy high resolution parallel hole collimator and Siemens Orbitor camera. (Simens medical systems. Inc., Hoffman Estates, III., USA). Anterior view of the knees was taken for 5 min, without magnification and both lateral views of symptomatic knees were obtained with electronic magnification (1.25, upto 2.0) for 8 min each. Disease processes such as DJD, traumatic arthritis, P-F tendonitis, SONK, meniscus tear are detected and illustrated along with normal knee scan finding. We believe LBSKM may not be as good as SPECT or pinhole imaging of the knees in the evaluation of knee pain but superior to routine WBBS in the nuclear medicine department with limited resources of instrumentation and manpower.

  7. MRI Evaluation of Resection Margins in Bone Tumour Surgery

    Directory of Open Access Journals (Sweden)

    Simon Vandergugten

    2014-01-01

    Full Text Available In 12 patients operated on for bone sarcoma resection, a postoperative magnetic resonance imaging of the resection specimens was obtained in order to assess the surgical margins. Margins were classified according to MRI in R0, R1, and R2 by three independent observers: a radiologist and two orthopaedic surgeons. Final margin evaluation (R0, R1, and R2 was assessed by a confirmed pathologist. Agreement for margin evaluation between the pathologist and the radiologist was perfect (κ=1. Agreement between the pathologist and an experienced orthopaedic surgeon was very good while it was fair between the pathologist and a junior orthopaedic surgeon. MRI should be considered as a tool to give quick information about the adequacy of margins and to help the pathologist to focus on doubtful areas and to spare time in specimen analysis. But it may not replace the pathological evaluation that gives additional information about tumor necrosis. This study shows that MRI extemporaneous analysis of a resection specimen may be efficient in bone tumor oncologic surgery, if made by an experienced radiologist with perfect agreement with the pathologist.

  8. Bone

    Science.gov (United States)

    Helmberger, Thomas K.; Hoffmann, Ralf-Thorsten

    The typical clinical signs in bone tumours are pain, destruction and destabilization, immobilization, neurologic deficits, and finally functional impairment. Primary malignant bone tumours are a rare entity, accounting for about 0.2% of all malignancies. Also benign primary bone tumours are in total rare and mostly asymptomatic. The most common symptomatic benign bone tumour is osteoid osteoma with an incidence of 1:2000.

  9. Human bone hardness seems to depend on tissue type but not on anatomical site in the long bones of an old subject.

    Science.gov (United States)

    Ohman, Caroline; Zwierzak, Iwona; Baleani, Massimiliano; Viceconti, Marco

    2013-02-01

    It has been hypothesised that among different human subjects, the bone tissue quality varies as a function of the bone segment morphology. The aim of this study was to assess and compare the quality, evaluated in terms of hardness of packages of lamellae, of cortical and trabecular bones, at different anatomical sites within the human skeleton. The contralateral six long bones of an old human subject were indented at different levels along the diaphysis and at both epiphyses of each bone. Hardness value, which is correlated to the degree of mineralisation, of both cortical and trabecular bone tissues was calculated for each indentation location. It was found that the cortical bone tissue was harder (+18%) than the trabecular one. In general, the bone hardness was found to be locally highly heterogeneous. In fact, considering one single slice obtained for a bone segment, the coefficient of variation of the hardness values was up to 12% for cortical bone and up to 17% for trabecular bone. However, the tissue hardness was on average quite homogeneous within and among the long bones of the studied donor, although differences up to 9% among levels and up to 7% among bone segments were found. These findings seem not to support the mentioned hypothesis, at least not for the long bones of an old subject.

  10. Evaluation of bone-mineral density by digital X-ray radiogrammetry (DXR) in pediatric renal transplant recipients

    Energy Technology Data Exchange (ETDEWEB)

    Mentzel, Hans-J.; Boettcher, Joachim; Malich, Ansgar; Pfeil, Alexander; Kaiser, Werner A. [Friedrich-Schiller-University Jena, Department of Pediatric Radiology, Jena (Germany); John, Ulrike; Misselwitz, Joachim [Friedrich-Schiller-University Jena, Department of Pediatric Nephrology, Jena (Germany); Vollandt, Ruediger [Friedrich-Schiller-University Jena, Institute of Medical Statistics, Computer Sciences and Documentation, Jena (Germany)

    2005-05-01

    Loss of bone mass and increased fracture risk are known complications after renal transplantation in adults. Risk factors include donor source, dialysis status prior to transplantation, aetiology of renal disease, transplant rejection and drug therapy, particularly steroids. In this preliminary study of quantification of bone loss in children after renal transplantation, we evaluated the applicability of digital X-ray radiogrammetry (DXR) of hand radiographs to estimate cortical bone mineral density (DXR-BMD). A total of 23 renal transplant recipients (9 girls, 14 boys; age 6.5-20 years, median 16.3 years) underwent DXR measurements for calculation of DXR-BMD and metacarpal index (DXR-MCI) using radiographs of the non-dominant left hand. The duration between transplantation and the DXR evaluation, the duration of dialysis and medication were considered. The results were compared to a local age-matched and gender-matched reference data base. Our study revealed a significant decrease in bone mineral density compared to an age-matched and sex-matched normal population (P<0.05). In three patients the DXR-BMD was reduced more than -2.5 SD. In 12 patients the DXR-BMD was between -1 and -2.5 SD, and in 7 patients the DXR-BMD was in the normal range. In one patient, evaluation was not possible. Fractures were documented in three patients following transplantation. Reduced DXR-BMD was not significantly associated with immunosuppressive therapy or the duration of dialysis, and there was no significant correlation between DXR-BMD and the time between transplantation and DXR evaluation. (orig.)

  11. 2D FEA of evaluation of micromovements and stresses at bone-implant interface in immediately loaded tapered implants in the posterior maxilla

    Directory of Open Access Journals (Sweden)

    Shrikar R Desai

    2013-01-01

    Full Text Available Aim: The aim of the study is to evaluate the influence implant length on stress distribution at bone implant interface in single immediately loaded implants when placed in D4 bone quality. Materials and Methods: A 2-dimensional finite element models were developed to simulate two types of implant designs, standard 3.75 mm-diameter tapered body implants of 6 and 10 mm lengths. The implants were placed in D4 bone quality with a cortical bone thickness of 0.5 mm. The implant design incorporated microthreads at the crestal part and the rest of the implant body incorporated Acme threads. The Acme thread form has a 29° thread angle with a thread height half of the pitch; the apex and valley are flat. A 100 N of force was applied vertically and in the oblique direction (at an angle of 45° to the long axis of the implants. The respective material properties were assigned. Micro-movements and stresses at the bone implant interface were evaluated. Results: The results of total deformation (micro-movement and Von mises stress were found to be lower for tapered long implant (10 mm than short implant (6 mm while using both vertical as well as oblique loading. Conclusion: Short implants can be successfully placed in poor bone quality under immediate loading protocol. The novel approach of the combination of microthreads at the crestal portion and acme threads for body portion of implant fixture gave promising results.

  12. The collective dose equivalent in evaluated region of bone-coal power stations and bone-coal shafts

    Institute of Scientific and Technical Information of China (English)

    ZHANG Liang; JIANG Shan; KONG Ling-Li; LI Ying; YE Ji-Da; SHI Jin-Hua; WU Zong-Mei

    2005-01-01

    During 1991-1993, the radioactivity levels of the bone-coal mines were investigated in Hubei, Hunan, Jiangxi, Zhejiang and Anhui Provinces, respectively, where the reserve of bone-coal is about 90% of our country's total reserve. The annual additional collective dose equivalent within 80km evaluated region of bone-coal power stations in Nijiangkou and Anren is 1.7 and 1.9 man .mSv,respectively,and that of Zhuantanyan bone-coal shaft is 1.4 man.mSv.The collective dose equivalent caused by bone-coal cinder brick produced for 25 years in the provinces is 1.6×105 man.Sv.

  13. Evaluation of heterotopic bone formation induced by squalane and bone morphogenetic protein composite.

    Science.gov (United States)

    Kawakami, T; Kawai, T; Takei, N; Kise, T; Eda, S; Urist, M R

    1997-04-01

    Bone morphogenetic protein is an important molecule whose bioactivity depends on the carrier. Squalane is used in the formulation of various kinds of cosmetics because it is easily emulsified and has the property of spreading well. Thus, squalane might be effective as a bone morphogenetic protein delivery system. As a test for this possibility, gelatin capsules containing squalane and bone morphogenetic protein (bovine derived partially purified) composite were implanted under the hind-quarter perimuscular membrane of ddY mice. Control capsules containing only bone morphogenetic protein were used for controls. The implants were radiographically and histologically examined at 1 to 4 weeks after the operation. According to the radiographic analysis, squalane and bone morphogenetic protein composite and bone morphogenetic protein only control specimens formed widespread heterotopic bone tissues. The amount of heterotopic bone formation in the composite experimental specimens was approximately 40% greater than that in the controls. Histologic examination of experimental and control specimens revealed varying amounts of perichondral ossification by 2 weeks. By 3 and 4 weeks, the bone deposits were colonized by hematopoietic bone marrow. Squalane was effective for the slow local release of bone morphogenetic protein. Furthermore, the squalane and bone morphogenetic protein composite was a reliable osteoinductive biomaterial.

  14. Clinical application of canal wall reconstruction with homograft cortical bone plate in canal wall down tympanoplasty%自体皮质骨外耳道重建在开放式鼓室成形术中的应用

    Institute of Scientific and Technical Information of China (English)

    马喆; 习国平; 张社江; 蔡爱军; 郝艳芳; 梁宝莲

    2012-01-01

    目的 对开放式鼓室成形术中利用自体皮质骨行外耳道重建的方法及疗效进行评价.方法 将接受手术治疗的胆脂瘤型中耳炎患者49例(49耳)分为两组.实验组,行开放式鼓室成形术+自体皮质骨外耳道重建术25例(耳);对照组,行常规开放式鼓室成形术+耳甲腔成形术24例(耳).术后随访6 ~ 36个月,观察两组患者术后听力结果、干耳率情况.结果 以术后语言频率气骨导差缩小>15 dB或气导听阈<40 dB为有效标准,实验组有效率68% (17/25),对照组有效率62.5% (15/24),组间比较无统计学意义(x2=0.1635,P>0.05).实验组干耳率为92.5%(23/25),明显高于对照组58.33%(14/24),差异有统计学意义(x2=4.363 6,P <0.05).实验组重建后的外耳道结构正常,无闭锁或狭窄情况发生.中耳乳突腔均接近正常.全部病例均无胆脂瘤复发.结论 开放式鼓室成形术加自体皮质骨外耳道重建术,能有效清除中耳病灶组织、恢复外耳道和中耳的结构,术后听力结果满意,干耳率高,是较为理想的手术方式.%Objective To evaluate the therapy of canal wall down tympanoplasty and canal reconstruction with homo-graft cortical bone plate. Methods Retrospective case review. 49 patients were divided into 2 groups. The experimental group that included 25 ears underwent canal wall down tympanoplasty and canal reconstruction with homograft cortical bone plate, while the control group that included 24 ears underwent regular canal wall down tympanoplasty with canal reconstruction. Follow up lasted 6-36 months and postoperative hearing and dry ear rate were evaluated. Results The criteria for success were defined as AB gap closure over 15 dB HL or air conduction threshold less than 40 dB HL (using the mean of 0. 5-, 1-, and 2-KHz threshold values). The experimental group's effective rate was 68% (17/25) and the control group's was 62. 5% (15/24). No significant difference was found between the

  15. Evaluation of Bone Mineral Density in Children with Thalassemia Major

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    Betül Bakan

    2012-12-01

    Full Text Available Aim: Fragile bones develop due to various factors in thalassemic patients. Even with optimum management, osteoporosis occurs, contributing to morbidity in majority of patients with thalassemia major (TM. Our aim was to evaluate bone health of thalassemic children using biochemical parameters and bone mineral density (BMD, and to emphasize the precautionary measures and early diagnosis of osteoporosis. Material and Methods: Thirteen children (5 females, 8 males, age <18 years with TM were included in the study. Age, duration, weight, height, transfusion frequency, medication use were recorded. Following laboratory analysis were obtained: Whole blood count, fasting blood glucose, ferritin, alanine aminotransferase, aspartate aminotransferase, calcium, phosphorus, alkaline phosphatase, thyroid stimulating hormone, free thyroxin, and intact parathyroid hormone (iPTH. BMD was determined using dual energy X-ray absorptiometry (DXA from femur and lumbar vertebrae. Patients with DXA Z-score <-2 was defined as osteoporotic. Results: The mean age was 7.85±3.17 years and body mass index (BMI was 14.68±1.93 kg/m2. The rest of the results were as follows: Lumbar BMD 0.464±0.108 g/cm2; total femur BMD 0.581± 0.114 g/cm2; lumbar DEXA Z-score 2.44±1.60; total femur DEXA -0.93±1.19. Osteoporosis ratio was determined as 69% in the lumbar vertebrae and 10% in the femur. A significant positive correlation was found between lumbar-femoral BMD and BMI, and a significant negative correlation was observed between femoral BMD and iPTH. Conclusion: BMD is low in thalassemic children. Despite regular transfusions and chelation therapy, osteoporosis starts early in life. (Turkish Journal of Osteoporosis 2012;18: 72-7

  16. A re-evaluation of the premaxillary bone in humans.

    Science.gov (United States)

    Barteczko, K; Jacob, M

    2004-03-01

    The discovery of the premaxillary bone (os incisivum, os intermaxillare or premaxilla) in humans has been attributed to Goethe, and it has also been named os Goethei. However, Broussonet (1779) and Vicq d'Azyr (1780) came to the same result with different methods. The first anatomists described this medial part of the upper jaw as a separate bone in the vertebrate skull, and, as we know, Coiter (1573) was the first to present an illustration of the sutura incisiva in the human. This fact, and furthermore its development from three parts:-(1) the alveolar part with the facial process, (2) the palatine process, and (3) the processus Stenonianus-can no longer be found in modern textbooks of developmental biology. At the end of the nineteenth and in the early twentieth century a vehement discussion focused on the number and position of its ossification centers and its sutures. Therefore, it is hard to believe that the elaborate work of the old embryologists is ignored and that the existence of a premaxillary bone in humans is even denied by many authors. Therefore this re-evaluation was done to demonstrate the early development of the premaxillary bone using the reconstructions of Felber (1919), Jarmer (1922) and data from our own observations on SEM micrographs and serial sections from 16 mm embryo to 68 mm fetus. Ossification of a separate premaxilla was first observed in a 16 mm embryo. We agree with Jarmer (1922), Peter (1924), and Shepherd and McCarthy (1955) that it develops from three anlagen, which are, however, not fully separated. The predominant sutura incisiva (rudimentarily seen on the facial side in a prematurely born child) and a shorter sutura intraincisiva argue in this sense. The later growth of this bone and its processes establish an important structure in the middle of the facial skull. Its architecture fits well with the functional test of others. We also focused on the relation of the developing premaxilla to the forming nasal septum moving from

  17. Comparison of bone scan with carbohydrate antigen 15-3 for evaluation of bone metastasis of brest cancer.

    Science.gov (United States)

    Mohammadzadeh, M; Alikhah, H; Zareh, A G A

    2010-02-15

    This study aimed at comparing the bone scan and CA15-3 titer in patients with breast cancer for evaluation of bone metastasis. Thirty five patients with definite diagnosis of breast cancer were evaluated in Tabriz Imam Khomeini Hospital from 2007 to 2008. Bone scan (99 mTc-MDP) performed in all patients. The serum CA15-3 was measured by ECLIA method. The increased level was considered as >30 U mL(-1). The serum level of CA15-3 was compared between the patients with and without bone metastasis, as well as its correlation with the extent of bone involvement. Thirty five patients with the mean age of 51.69 +/- 10.77 (34-81) years were enrolled in the study. According to bone scan results, 24 (68.8%) patients revealed bone metastasis. The mean level of serum CA15-3 was significantly higher in patents with bone metastasis than patients without metastasis (26.37 +/- 4.74 U mL(-1) vs. 19.09 +/- 1.99 U mL(-1); p 21.8 U mL(-1) for the serum level of CA15-3 in our patients, with a sensitivity and specificity of 91.7 and 91%, respectively. Serum level of CA15-3 is higher in the patients with bone metastatic breast cancer; however, the recommended cut-off point might not be suitable for Iranian patients. Further studies with large sample sizes are recommended.

  18. Neuropsychological Evaluation and Follow-Up of Children with Cerebellar Cortical Dysplasia

    Science.gov (United States)

    Jissendi-Tchofo, Patrice; Pandit, Florence; Soto-Ares, Gustavo; Vallee, Louis

    2011-01-01

    Aim: To describe neuropsychological disturbances and the developmental course associated with cerebellar cortical dysplasia (CCD). Method: The neuroimaging findings from 10 children (five males, five females; aged 3-10y) with CCD were reviewed and classified. These children all underwent clinical neurological examination and neuropsychological…

  19. EVALUATION OF TECHNIQUES FOR CLEANING EMBALMED CADAVER BONES

    Directory of Open Access Journals (Sweden)

    Bhawani Shankar Modi

    2014-12-01

    Full Text Available Objective: The present study was conducted to find new technique for development of bone specimens from cadavers. Material and methods: Long bones, skull and other bones from embalmed cadaver were taken and cleansed by various methods. Four methods were employed for preparing specimens. In 1st method bones were boiled in tap water for 7-8 hours on gas stove. In 2nd method bones were immersed in water with addition of detergent at constant temperature. In 3rd method bones were kept at constant temperature in water without addition of detergent. In 4th method bones were buried for one month under superficial surface of soil during rainy season after boiling the bones for 7-8 hours Observations: Use of detergent in warm water (65o C was good for cleaning long bones while best result for long bones as well as skull was seen with boiling followed by burial of embalmed specimens. Results were found as expected. Time consumed in the present study was less than old classical methods. Bones specimens formed were of high quality. Conclusions: Preparation of bone specimen by embalmed cadaver can be of immense value and time saver for many research institutes to get their self-prepared specimens. There are many more ways which has to be modified or rediscovered in this area of research, which has been neglected so far.

  20. Evaluation of femur of orchiectomized Guinea pigs by bone densitometry using dual-energy X-ray absorptiometry (DXA) and mechanical testing

    Energy Technology Data Exchange (ETDEWEB)

    Estanislau, Cristiane de Abreu; Rahal, Sheila Canavese; Araujo, Fabio Andre Pinheiro de, E-mail: crisestanislau@hotmail.co, E-mail: sheilacr@fmvz.unesp.b, E-mail: fabioandre@fmvz.unesp.b [Universidade Estadual Paulista (UNESP), Botucatu, SP (Brazil). Faculdade de Medicina, Veterinaria e Zootecnia. Dept. de Cirurgia e Anestesiologia Veterinaria; Sergio Swain Muller, E-mail: diretoria@fmb.unesp.b [Universidade Estadual Paulista (UNESP), Botucatu, SP (Brazil). Faculdade de Medicina, Veterinaria e Zootecnia. Dept. de Cirurgia e Ortopedia; Louzada, Mario Jefferson Quirino, E-mail: louzada@fmva.unesp.b [Universidade Estadual Paulista (UNESP), Aracatuba, SP (Brazil). Faculdade de Medicina Veterinaria; Estanislau, Caroline de Abreu, E-mail: caestanis@hotmail.co

    2010-03-15

    The aim of this study was to evaluate the effects of castration on bones in the male guinea pigs and to observe whether mechanical testing correlates with dual-energy X-ray absorptiometry (DXA). Twelve male guinea pigs (Cavia porcellus), aged 21-27 days, and with average initial weight of 279 grams were used. The animals were equally allocated to two groups: GI - orchiectomized animals and GII - intact control animals. They underwent euthanasia at seven months following surgery. DXA measurement was performed at the mid third of the right femoral diaphysis in the cortical region and at the left femoral neck in order to verify its correlation with results of mechanical testing. Three-point bending test of right femur and axial compression test of left femur were performed. Bone mineral density of GI was significantly lower only at femoral neck. No differences were observed in the maximum load values between GI and GII for both bending and axial compression tests. The bending test revealed lower bone stiffness in GI compared to GII, but in the axial compression test no differences between groups were observed. Only left femur showed positive correlation coefficient between maximum load and bone mineral density according to Pearson's correlation coefficient. The results suggest that hormonal deprivation in guinea pigs induces reduction of bone mineral density, especially in the femoral neck area and reduction of bone stiffness in the mid-femoral diaphysis. (author)

  1. Rapid evaluation of the durability of cortical neural implants using accelerated aging with reactive oxygen species

    Science.gov (United States)

    Takmakov, Pavel; Ruda, Kiersten; Phillips, K Scott; Isayeva, Irada S; Krauthamer, Victor; Welle, Cristin G

    2017-01-01

    Objective A challenge for implementing high bandwidth cortical brain–machine interface devices in patients is the limited functional lifespan of implanted recording electrodes. Development of implant technology currently requires extensive non-clinical testing to demonstrate device performance. However, testing the durability of the implants in vivo is time-consuming and expensive. Validated in vitro methodologies may reduce the need for extensive testing in animal models. Approach Here we describe an in vitro platform for rapid evaluation of implant stability. We designed a reactive accelerated aging (RAA) protocol that employs elevated temperature and reactive oxygen species (ROS) to create a harsh aging environment. Commercially available microelectrode arrays (MEAs) were placed in a solution of hydrogen peroxide at 87 °C for a period of 7 days. We monitored changes to the implants with scanning electron microscopy and broad spectrum electrochemical impedance spectroscopy (1 Hz–1 MHz) and correlated the physical changes with impedance data to identify markers associated with implant failure. Main results RAA produced a diverse range of effects on the structural integrity and electrochemical properties of electrodes. Temperature and ROS appeared to have different effects on structural elements, with increased temperature causing insulation loss from the electrode microwires, and ROS concentration correlating with tungsten metal dissolution. All array types experienced impedance declines, consistent with published literature showing chronic (>30 days) declines in array impedance in vivo. Impedance change was greatest at frequencies <10 Hz, and smallest at frequencies 1 kHz and above. Though electrode performance is traditionally characterized by impedance at 1 kHz, our results indicate that an impedance change at 1 kHz is not a reliable predictive marker of implant degradation or failure. Significance ROS, which are known to be present in vivo, can create

  2. Quantitative evaluation of regularized phase retrieval algorithms on bone scaffolds seeded with bone cells

    Science.gov (United States)

    Weber, L.; Langer, M.; Tavella, S.; Ruggiu, A.; Peyrin, F.

    2016-05-01

    In the field of regenerative medicine, there has been a growing interest in studying the combination of bone scaffolds and cells that can maximize newly formed bone. In-line phase-contrast x-ray tomography was used to image porous bone scaffolds (Skelite©), seeded with bone forming cells. This technique allows the quantification of both mineralized and soft tissue, unlike with classical x-ray micro-computed tomography. Phase contrast images were acquired at four distances. The reconstruction is typically performed in two successive steps: phase retrieval and tomographic reconstruction. In this work, different regularization methods were applied to the phase retrieval process. The application of a priori terms for heterogeneous objects enables quantitative 3D imaging of not only bone morphology, mineralization, and soft tissue formation, but also cells trapped in the pre-bone matrix. A statistical study was performed to derive statistically significant information on the different culture conditions.

  3. Tunes stuck in your brain: The frequency and affective evaluation of involuntary musical imagery correlate with cortical structure.

    Science.gov (United States)

    Farrugia, Nicolas; Jakubowski, Kelly; Cusack, Rhodri; Stewart, Lauren

    2015-09-01

    Recent years have seen a growing interest in the neuroscience of spontaneous cognition. One form of such cognition is involuntary musical imagery (INMI), the non-pathological and everyday experience of having music in one's head, in the absence of an external stimulus. In this study, aspects of INMI, including frequency and affective evaluation, were measured by self-report in 44 subjects and related to variation in brain structure in these individuals. Frequency of INMI was related to cortical thickness in regions of right frontal and temporal cortices as well as the anterior cingulate and left angular gyrus. Affective aspects of INMI, namely the extent to which subjects wished to suppress INMI or considered them helpful, were related to gray matter volume in right temporopolar and parahippocampal cortices respectively. These results provide the first evidence that INMI is a common internal experience recruiting brain networks involved in perception, emotions, memory and spontaneous thoughts. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  4. [Evaluation of bone mineral density using digital image processing in children receiving anticonvulsants].

    Science.gov (United States)

    Suzuki, Keiko; Ueda, Satoru; Umezu, Ryouji; Matsuoka, Hisafumi; Sugihara, Shigetaka

    2007-09-01

    Bone mineral density (BMD) increases rapidly in a biphasic manner in childhood. During and after adolescence, BMD correlates more closely with bone age than chronological age. Digital image processing (DIP) allows the rapid assessment of BMD and bone age on one X-ray film. Herein, using DIP methods, the effects of various anticonvulsants on chronological and bone age were evaluated in 98 epilepsy patients (age range, 3-15 years) with no intellectual or motor disorders or diseases affecting bone metabolism. All patients were taking one or a combination of the following anticonvulsants: valproate sodium (VPA); carbamazepine (CBZ); and phenobarbital (PB). Bone maturation scores for radius-ulnar-short bones (RUS) were calculated using Tanner-Whitehouse 2 methods. Bone age was determined based on standard Japanese bone-maturation scores. In each patient, Z-scores for chronological and bone ages were calculated by subtracting standard BMD for gender and age from each BMD, then dividing the result by the standard deviation. The Z-score for each drug in relation to the administration period was analyzed using the Mann-Whitney test. For chronological age, significant differences in BMD were observed regarding the administration periods in children taking multiple drugs, but not in children on VPA, CBZ, or PB monotherapy. For bone age, no significant differences in BMD were observed regarding the administration periods for all drugs. Children taking multiple drugs showed a significant negative correlation between administration period and Z-scores for BMD calculated based on chronological age (Spearman rank correlation: - 0.457, p = 0.008), but not bone age. Among children receiving long-term VPA administration, bone age was delayed approximately 1 year, and bone maturation may have been delayed. No delay in bone age was noted among children receiving long-term administration of multiple drugs, suggesting that these anticonvulsants do not influence bone maturity. These

  5. Secondary alveolar bone grafting in combination with autologous iliac crest cortical plate and concellous bone for 19 adult cleft patients%自体髂骨皮质骨块与松质骨联合移植修复成人牙槽突裂19例分析

    Institute of Scientific and Technical Information of China (English)

    李增健; 卢利; 金山; 任媛媛; 刘强; 张斌; 张蕾; 吴楠; 杨鸣良; 王绪凯

    2012-01-01

    Objective To retrospectively study secondary alveolar bone grafting in combination with autologous iliac crest cortical bone and concellous bone for adult cleft patients. Methods Analveolar bone grafting procedure in combination with autologous illiac crest cortical bone and concellous bone has been applied in 19 adult cleft patients since 2008. A water-tight mucocusperiosteum pocket was formed around the alveolar cleft. The iliac concellous bone was put into the alveolar cleft with tender pressing. The carved iliac crest cortical bone was then covered on to the labial surface of alveolar cleft and pyriform aperture with titanium screws. Results Based on Bergland's criterion, the overall survival rate of bone grafting was 84.2% , clinical success rate was 73.7% , clinical failure rate was 26. 3%. Oral-nasal fistular recurred in 2 patients. Conclusion Secondary alveolar bone grafting in combination with autologous iliac crest cortical bone and concellous bone can effectively improve the grafting survival rate and keep a sufficient volume in regions of cleft and the pyriform aperture of adult cleft patients.%目的 观察自体髂骨块和松质骨联合移植修复成人牙槽突裂的效果.方法 对2008年以来在我院就诊的成人牙槽突裂患者19例采用自体髂骨块和松质骨联合移植修复.将髂松质骨填充牙槽突裂间隙内,用骨块恢复梨状孔边缘形态和鼻翼基底部高度后,采用微型钛板和单皮质钛钉固定.术后1年复查进行Bergland 分级评价.结果 植入骨成活率(Ⅰ~Ⅲ级)为84.2%,临床成功率(Ⅰ、Ⅱ级)为73.7%,临床失败率(Ⅲ、Ⅳ级)为26.3%.2例患者再次出现口鼻瘘孔.结论 自体髂骨块和松质骨联合移植修复成人牙槽突裂可以有效恢复牙槽突高度,增加患侧梨状孔周围骨量.

  6. Quantitative assessment of interradicular bone density in the maxilla and mandible: implications in clinical orthodontics

    Science.gov (United States)

    2013-01-01

    Background Bone density at the interradicular area plays an important role during orthodontic treatment. In view of this fact, the study was designed to quantitatively evaluate the bone density at the interradicular areas of the alveolar and basal bones of maxilla and mandible by computed tomography. Methods One hundred and nine computed tomographic images were randomly selected, and bone density was measured in Hounsfield units (HU) with bone mineral density software (Siemens VA20A_SP3A). The sample consisted of 78 males (mean age 29.5 years, range 20 to 40 years) and 31 females (mean age 27.6 years, range 20 to 40 years). Cortical and cancellous bone density was measured at the interradicular areas at the alveolar and basal bone levels of the maxilla and mandible, and the data was subjected to statistical analysis for comparisons. Results The highest cortical bone density was observed between the second premolar and first molar at the alveolar bone level and between the first and second molars at the basal bone level in the maxilla. Maxillary tuberosity showed the least bone density. The density of the cortical bone was greater in the mandible than in the maxilla and showed a progressive increase from the incisor to the retromolar area. The basal bone showed a higher density thanthe alveolar bone. Conclusion Different qualities of the bone were found in the anatomic regions studied, which confirms the importance of knowledge of site-specific bone tissue density to correlate with various clinical findings. PMID:24325883

  7. [Evaluation of reparative regeneration of the jaw bone by microfocus roentgenography in an experiment].

    Science.gov (United States)

    Vasil'ev, A Iu; Bulanova, I M; Mal'ginov, N N; Tarasenko, I V; Tarasenko, S V; Kiseleva, E V; Drobyshev, A Iu; Volozhin, A I

    2009-01-01

    In experiment on 16 grown-up chinchilla rabbits the dynamic of reparative regeneration was evaluated by digital microfocal rontgenography in the terms of 1, 2 and 4 months. Bone defect of the 8capital CHE, Cyrillic8 mm size in the region of mandible angle was caused by surgical laser Smart 2940 D+ on the right side and by physiodespenser Surgec XT on the left side. Surgical laser use let to reduce intact mother bone traumatisation and to improve remote results of bone tissue regeneration. After bone defect creation bone tissue regeneration was put into effect by all 3 callus types - endosteal, periosteal and intermediary.

  8. Histologic and morphologic evaluation of explanted bone anchors from bone-anchored hearing aids.

    Science.gov (United States)

    Mlynski, Robert; Goldberg, Eva; Ebmeyer, Joerg; Scheich, Matthias; Gattenlöhner, Stefan; Schwager, Konrad; Hagen, Rudolf; Shehata-Dieler, Wafaa

    2009-05-01

    Bone-anchored hearing aids are a standard option in rehabilitation of patients with conductive or mixed hearing loss, and also CROS fitting. However, the skin-penetrating bone anchor repeatedly gives reason for discussion about the risk of infection of surrounding tissues as a major cause of malfunction. In the present study, explanted bone anchors with surrounding bone and soft tissue were examined and compared with the morphology of lost implants. The anchors originated from five patients. Two needed explantation due to deafness with the need of cochlea implantation. A third patient underwent explantation due to meningeal irritation by the bone anchor. Another patient lost the implant due to mechanical stress shortly after implantation. The last implant was lost in a child without apparent reason. All implants were clinically free of infection and had been stable for a median implantation period of 12 months. During the explantation procedure, the fixtures were recovered together with the attached soft tissue and bone. The specimens were examined by light microscopy or scanning electron microscopy (SEM). Sectioning for light microscopy was performed with a diamond-coated saw microtome. Histopathologic examination of the surrounding skin and subcutaneous soft tissue showed slight inflammation in one case only. The bone was regularly vital, presenting no signs of inflammation. The threads of the fixtures were filled with bone, with particularly strong attachment to the flank of traction. The SEM investigation exposed the ultrastructural interaction of bone with the implant surface. Filiform- and podocyte-like processes of osteocytes attach to the implant; lost implants did not reflect these features. Implant integration involves both osseointegration as well as soft tissue integration. Titanium oxide as the active implant surface promotes this integration even in unstable implants. The morphologic analysis exposed structural areas of the implant with weak bone

  9. Radiogrammetric analysis of upper limb long bones

    Directory of Open Access Journals (Sweden)

    Stojanović Zlatan

    2011-01-01

    Full Text Available Radiogrammetry is radiological method of bone mineral density quantification. Besides giving an insight in diagnostics and evolution of metabolic bone disorders (osteoporosis, osteomalacia, osteitis deformans- Paget's disease, it can also explain some specific biomechanical characteristics of bone structures. The aim of this study is to evaluate the significance and perspectives of radiogrammetry as a scientific model for further inquiry of skeletal system. The work demonstrates mathematical parameters (Ca-Cortical area, CI- Cortical index, GI- Garn's index, ESI- Exton Smith's index of upper limb long bones (humerus, radius, ulna. Two standard radiological projections of bones were taken: antero-posterior (AP and latero-lateral (LL. Correlation with metacarpal and lower limb bones was also performed. The value of the cortical area of humerus is significantly higher comparing with the two other examined bones (Xmean 2,2443 cm2, p < 0.01. Radial bone has the highest values of the relational mathematical parameters, which implicates its higher strength by volumetric unit concerning humerus and ulna. Despite the development of contemporary osteometric procedures (ultrasound densitometry, dual X-ray absorptiometry, digital X-ray radiogrammetry, the classical radiogrammetry sustains its important role in diagnostics of metabolic bone disorders and it can be successfully used for biomechanical inquiry of skeletal system.

  10. Estimation of In vivo Cancellous Bone Elasticity

    Science.gov (United States)

    Otani, Takahiko; Mano, Isao; Tsujimoto, Toshiyuki; Yamamoto, Tadahito; Teshima, Ryota; Naka, Hiroshi

    2009-07-01

    The effect of decreasing bone density (a symptom of osteoporosis) is greater for cancellous bone than for dense cortical bone, because cancellous bone is metabolically more active. Therefore, the bone density or bone mineral density of cancellous bone is generally used to estimate the onset of osteoporosis. Elasticity or elastic constant is a fundamental mechanical parameter and is directly related to the mechanical strength of bone. Accordingly, elasticity is a preferable parameter for assessing fracture risk. A novel ultrasonic bone densitometer LD-100 has been developed to determine the mass density and elasticity of cancellous bone with a spatial resolution comparable to that of peripheral quantitative computed tomography. Bone density and bone elasticity are evaluated using ultrasonic parameters based on fast and slow waves in cancellous bone by modeling the ultrasonic wave propagation path. Elasticity is deduced from the measured bone density and the propagation speed of the fast wave. Thus, the elasticity of cancellous bone is approximately expressed by a cubic equation of bone density.

  11. Evaluation of the efficacy of zoledronic acid and amifostine on radiation induced bone loss in mice

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Wook; Lee, Sueum; Kang, Sohi; Moon, Cahng Jong; Kim, Jong Choon; Kim, Sung Ho [College of Veterinary Medicine, Chonnam National University, Gwangju (Korea, Republic of); Jung, Uhee; Jo, Sung Kee [Advanced Radiation Technology Institute, Jeungeup (Korea, Republic of); Jang, Jong Sik [College of Ecology and Environmental Science, Kyungpook National University, Sangju (Korea, Republic of)

    2016-09-15

    This study investigated the effects of zoledronic acid (ZA) on radiation-induced bone loss in C3H/HeN mice. C3H/HeN mice were divided into sham control and three irradiated groups (3 Gy, gamma ray). The irradiated mice were treated for 12 weeks with vehicle, amifostine (intraperitoneal injection), or ZA (subcutaneous injection). Grip strength, uterus weight, and serum alkaline phosphatase (ALP), and tartrate-resistant acid phosphatase (TRAP) levels were measured. Tibiae were analyzed using micro-computed tomography. Treatment of ZA (100 μg·kg{sup -1}·week{sup -1}) significantly preserved trabecular bone volume, trabecular thickness, trabecular number, trabecular separation, bone mineral density of proximal tibia metaphysic, and cortical bone volume, but did not alter the uterus weight of the mice. The administration of ZA for 12 weeks lowered serum ALP and TRAP levels in irradiated mice, suggesting that ZA can reduce the bone turnover rate in mice. No differences were apparent between the amifostine-treated group and the irradiation control group. The results indicate that ZA can prevent radiation-induced bone loss in mice.

  12. 3D computed tomographic evaluation of secondary alveolar bone grafts in cleft lip and palate patients

    Energy Technology Data Exchange (ETDEWEB)

    Ohkubo, Fumio; Akai, Hidemi; Hosaka, Yoshiaki [Showa Univ., Tokyo (Japan). School of Medicine

    2001-04-01

    Alveolar bone grafting in patients with cleft lip and palate has becomes a routine part of most treatment regimes. This study was undertaken to estimate how much bone needs to be grafted into the cleft cavity and to evaluate the grafted bone using 3-DCT over a period from the early postoperative stage to after one year. Seventy-five patients divided into four groups according to the type of cleft were studied. All patients underwent secondary alveolar bone grafting using particulate cancellous bone from the anterior iliac crest. The bone graft areas were divided into two regions: the extra-cleft region and the intra-cleft region. The weight and the volume of the grafted bone were correlated and the average density was 1.5 g/ml regardless of the cleft type. The bone in the extra-cleft region could be seen in almost all slices of the CT scans, from the lower alveolar process to the piriform aperture. The extra-cleft graft ratio of unilateral and bilateral cleft lip and palate is higher than that of cleft lip and alveolus. The extra-cleft grafting is necessary to restore facial symmetry. The grafted bone was decreased in both height and volume following three months and adequate bone bridging was maintained for one year. We concluded that 3-DCT findings are one of the most valuable methods to evaluate postoperative conditions after alveolar bone grafting. (author)

  13. Incorporación de aloinjertos óseos intercalares corticales: Estudio experimental en conejos Incorporation of cortical intercalary bone allografts: Experimental study on rabbits

    Directory of Open Access Journals (Sweden)

    S. Amillo

    2003-12-01

    Full Text Available Se realiza un estudio experimental en 40 conejos para valorar la incorporación de grandes aloinjertos óseos intercalares y la influencia de la congelación en el injerto óseo. En 36 conejos adultos se procedió a resecar 3 centímetros diafisarios de tibia y el defecto se reconstruyó con diferente tipo de injerto óseo: autoinjerto fresco y autoinjerto congelado, aloinjerto fresco y aloinjerto congelado; la osteosíntesis se realizó con dos agujas de Kirschner intramedulares. Se hicieron estudios radiológicos mensuales hasta el sacrificio, a los 2, 4 y 8 meses. Se hizo un estudio densitométrico, histológico y de diafanización con técnica de Spalteholz de las tibias. En 24 animales se administraron 25 mg/kg de oxytetraciclina al 3º y 6º días antes del sacrificio para estudiar la velocidad de aposición ósea en el injerto. Observamos una consolidación radiológica buena y excelente en el 80% de los injertos (99% en los autoinjertos y 66% en los aloinjertos. La densidad ósea mostraba un descenso hasta el 4º mes debido a la reabsorción ósea excepto en el grupo de los aloinjertos frescos. La revascularización de los aloinjertos fue más lenta y pobre que en los autoinjertos, pero con el mismo patrón vascular. La incorporación y neoformación ósea fueron mayores en los autoinjertos sin diferencias significativas con los aloinjertos congelados. La velocidad de aposición ósea no se modificó con los diferentes tipos de injertos óseos utilizados. La congelación facilita y acelera la incorporación y cantidad de neoformación ósea de los aloinjertos.An experimental study was carried out on 40 rabbits in order to evaluate the incorporation of large intercalary bone allografts and the influence of freezing on the bone graft. In 36 rabbits resection of 3 centimetres of diaphysis of the tibia was carried out and the defect was rebuilt with different types of bone graft: fresh autograft and frozen autograft, fresh allograft and

  14. Bone Mineral Density Evaluation in Four Different Occupational Groups

    Directory of Open Access Journals (Sweden)

    Mustafa Turgut Yıldızgören

    2015-04-01

    Full Text Available Objective: The aim of this study was to evaluate bone mineral density (BMD and to discuss the potential risk factors for osteoporosis in four different occupational groups. Materials and Methods: In this study, 100 males who were admitted to our clinics for their periodic occupational controls and 40 healthy subjects were included. Demographic features of the participants were recorded. BMD was evaluated by Dual-energy x-ray absorptiometry (DXA from lumbar vertebrae and proximal femur. Results: Participants were mainly from the following four occupational groups; accumulator manufacturers (n=30, 21.4%, painting workers (n=30, 21.4%, welders (n=15, 10.7%, and quartz miners (n=25, 17.9% sectors. In addition, there were 40 healthy subjects (28.6%. Compared with the control group, femoral neck T-scores (p=0.023 and Z-scores (p=0.031 were significantly lower in miners. L2-L4 BMD values were significantly lower in accumulator manufacturers (p=0.041 and quartz miners (p=0.022 as compared with the control group. Conclusion: Workers in the accumulator and mining sectors had lower BMD than control subjects. Clinicians should keep in mind occupational risk factors related with chemical exposure for osteoporosis while questioning osteoporosis risk factors. (Turkish Journal of Osteoporosis 2015;21: 19-22

  15. EVALUATION OF NECK SHAFT ANGLE OF FEMUR ON DRY BONES

    Directory of Open Access Journals (Sweden)

    Radha

    2015-04-01

    Full Text Available BACKGROUND: Evaluation of the neck shaft angle of femur helps to understand clinical relevance in bio mechanics of the hip joint. It helps for the better treatment of different pathological conditions of hip and femur and also to design prosthesis. Femoral neck shaft angle is important to convey the information regarding the race to which they belong. Hence the present study was under taken to determine the neck shaft angle of femur in humans. OBJECTIVE: 1. To correct the different types of deformity and to have a normal good walking Mechanism. 2. To know the recent methodology and attempt to evaluate the range of normal Angles of femora and their sex differences. METHODS: ANTHROPOMETRIC: 100 Adult dry bones were studied and analyzed . The neck shaft angle of femur was measured by tracing outlines of contours of all femora. RESULTS: The neck shaft angle of the femur have revealed that there is no much difference in between males and females. There was slightly higher 0.2° in females. INTERPRETATION & CONCLUSION: There was no significant gender difference in neck shaft angle. The Knowledge of knowing the neck shaft angle helps to understand the Biomechanics of the hip joint and also for better treatment of pathological condition of hip and femur.

  16. Evaluation of bone response to synthetic bone grafting material treated with argon-based atmospheric pressure plasma

    Energy Technology Data Exchange (ETDEWEB)

    Beutel, Bryan G., E-mail: bryanbeutel@gmail.com; Danna, Natalie R.; Gangolli, Riddhi; Granato, Rodrigo; Manne, Lakshmiprada; Tovar, Nick; Coelho, Paulo G.

    2014-12-01

    Bone graft materials are utilized to stimulate healing of bone defects or enhance osseointegration of implants. In order to augment these capabilities, various surface modification techniques, including atmospheric pressure plasma (APP) surface treatment, have been developed. This in vivo study sought to assess the effect of APP surface treatment on degradation and osseointegration of Synthograft™, a beta-tricalcium phosphate (β-TCP) synthetic bone graft. The experimental (APP-treated) grafts were subjected to APP treatment with argon for a period of 60 s. Physicochemical characterization was performed by environmental scanning electron microscopy, surface energy (SE), and x-ray photoelectron spectroscopy analyses both before and after APP treatment. Two APP-treated and two untreated grafts were surgically implanted into four critical-size calvarial defects in each of ten New Zealand white rabbits. The defect samples were explanted after four weeks, underwent histological analysis, and the percentages of bone, soft tissue, and remaining graft material were quantified by image thresholding. Material characterization showed no differences in particle surface morphology and that the APP-treated group presented significantly higher SE along with higher amounts of the base material chemical elements on it surface. Review of defect composition showed that APP treatment did not increase bone formation or reduce the amount of soft tissue filling the defect when compared to untreated material. Histologic cross-sections demonstrated osteoblastic cell lines, osteoid deposition, and neovascularization in both groups. Ultimately, argon-based APP treatment did not enhance the osseointegration or degradation of the β-TCP graft. Future investigations should evaluate the utility of gases other than argon to enhance osseointegration through APP treatment. - Highlights: • Degradation/osseointegration of bone graft treated with argon-based APP is studied. • APP treatment did

  17. High-strength mineralized collagen artificial bone

    Science.gov (United States)

    Qiu, Zhi-Ye; Tao, Chun-Sheng; Cui, Helen; Wang, Chang-Ming; Cui, Fu-Zhai

    2014-03-01

    Mineralized collagen (MC) is a biomimetic material that mimics natural bone matrix in terms of both chemical composition and microstructure. The biomimetic MC possesses good biocompatibility and osteogenic activity, and is capable of guiding bone regeneration as being used for bone defect repair. However, mechanical strength of existing MC artificial bone is too low to provide effective support at human load-bearing sites, so it can only be used for the repair at non-load-bearing sites, such as bone defect filling, bone graft augmentation, and so on. In the present study, a high strength MC artificial bone material was developed by using collagen as the template for the biomimetic mineralization of the calcium phosphate, and then followed by a cold compression molding process with a certain pressure. The appearance and density of the dense MC were similar to those of natural cortical bone, and the phase composition was in conformity with that of animal's cortical bone demonstrated by XRD. Mechanical properties were tested and results showed that the compressive strength was comparable to human cortical bone, while the compressive modulus was as low as human cancellous bone. Such high strength was able to provide effective mechanical support for bone defect repair at human load-bearing sites, and the low compressive modulus can help avoid stress shielding in the application of bone regeneration. Both in vitro cell experiments and in vivo implantation assay demonstrated good biocompatibility of the material, and in vivo stability evaluation indicated that this high-strength MC artificial bone could provide long-term effective mechanical support at human load-bearing sites.

  18. Deciphering Seasonal Variations of Diet and Water in Modern White-Tailed Deer by In Situ Analysis of Osteons in Cortical Bone

    Science.gov (United States)

    Larson, T. E.; Longstaffe, F. J.

    2004-12-01

    In situ stable carbon and oxygen isotope compositions of biogenic apatite were obtained from longitudinally-cut sections of cortical bone from femurs of modern domesticated sheep and free-range White-Tailed deer, using an IR-laser and a GC-continuous flow interface. Ablation pits averaged 200x50 microns, making it possible to analyze individual osteons. Since cortical bone is remodelled along osteons throughout a mammal's lifetime, isotopic data at this resolution provides information about seasonal variations in diet and drinking water. The O-isotope results were calibrated using laser analyses of NBS-18 and NBS-19, which produced a value of 26.39±0.46 permil (n=27) for WS-1 calcite (accepted value, 26.25 permil). C-isotope results were calibrated using a CO2 reference gas, producing a value of 0.76±0.40permil (n=27) for WS-1, also in excellent agreement with its accepted value of 0.74 permil. Average O- and C-isotope values for a local domestic sheep (southwestern Ontario, Canada) were 12.20±0.58 and -15.70±0.35 permil (n=27), respectively. No isotopic trend occurred along or across individual osteons. This pattern is consistent with the sheep's relatively unchanging food and water sources. The free-range White-Tailed deer came from Pinery Provincial Park (PPP), southwestern Ontario. Its O- and C-isotope compositions varied systematically across individual osteons and were negatively correlated (R2=0.56). O-isotope values ranged from 13.4 to 15.5 permil; the highest values correlated with summer and the lowest values, with winter. The O-isotope compositions of the main water source (Old Ausable River Channel) varied similarly during the deer's lifetime: winter average, -10.7±0.5 permil; summer average, -8.6±0.4 permil. The C-isotope results for the deer osteons varied from -19.7 to -15.9 permil. This variation can be explained by changes in food sources. Summer diets of deer in PPP consist mainly of leafy fractions of C3 vegetation, especially sumac, cedar

  19. Evaluation of bone remodeling around single dental implants of different lengths: a mechanobiological numerical simulation and validation using clinical data.

    Science.gov (United States)

    Sotto-Maior, Bruno Salles; Mercuri, Emílio Graciliano Ferreira; Senna, Plinio Mendes; Assis, Neuza Maria Souza Picorelli; Francischone, Carlos Eduardo; Del Bel Cury, Altair Antoninha

    2016-01-01

    Algorithmic models have been proposed to explain adaptive behavior of bone to loading; however, these models have not been applied to explain the biomechanics of short dental implants. Purpose of present study was to simulate bone remodeling around single implants of different lengths using mechanoregulatory tissue differentiation model derived from the Stanford theory, using finite elements analysis (FEA) and to validate the theoretical prediction with the clinical findings of crestal bone loss. Loading cycles were applied on 7-, 10-, or 13-mm-long dental implants to simulate daily mastication and bone remodeling was assessed by changes in the strain energy density of bone after a 3, 6, and 12 months of function. Moreover, clinical findings of marginal bone loss in 45 patients rehabilitated with same implant designs used in the simulation (n = 15) were computed to validate the theoretical results. FEA analysis showed that although the bone density values reduced over time in the cortical bone for all groups, bone remodeling was independent of implant length. Clinical data showed a similar pattern of bone resorption compared with the data generated from mathematical analyses, independent of implant length. The results of this study showed that the mechanoregulatory tissue model could be employed in monitoring the morphological changes in bone that is subjected to biomechanical loads. In addition, the implant length did not influence the bone remodeling around single dental implants during the first year of loading.

  20. Bone Structural Changes and Estimated Strength After Gastric Bypass Surgery Evaluated by HR-pQCT

    DEFF Research Database (Denmark)

    Frederiksen, Katrine Diemer; Hanson, Stine; Hansen, Stinus;

    2016-01-01

    Roux-en-Y gastric bypass surgery (RYGB) is an effective treatment of morbid obesity, with positive effects on obesity-related complications. The treatment is associated with bone loss, which in turn might increase fracture risk. The aim of this study was to evaluate changes in bone mineral densit...... increased risk of fracture in bariatric patients after surgery. We only observed bone structural changes in the weight-bearing bone, which indicates that mechanical un-loading is the primary mediator.......Roux-en-Y gastric bypass surgery (RYGB) is an effective treatment of morbid obesity, with positive effects on obesity-related complications. The treatment is associated with bone loss, which in turn might increase fracture risk. The aim of this study was to evaluate changes in bone mineral density...

  1. Relationship between the CT Value and Cortical Bone Thickness at Implant Recipient Sites and Primary Implant Stability with Comparison of Different Implant Types.

    Science.gov (United States)

    Howashi, Miori; Tsukiyama, Yoshihiro; Ayukawa, Yasunori; Isoda-Akizuki, Kei; Kihara, Masafumi; Imai, Yu; Sogo, Motofumi; Koyano, Kiyoshi

    2016-02-01

    Studies have shown that bone quality at the implant recipient site can influence primary stability. The aims of this study were to explore the quantitative estimation of the primary stability of implants preoperatively using CT values and to examine the effect of different implant designs with recommended socket preparation on primary stability. Forty-four fresh porcine femoral heads were prepared. The bone surrounding implant sockets was preoperatively evaluated by helical CT. Forty-four implants (φ 4.3 × 10 mm), 22 straight and 22 tapered, were placed according to the manufacturer's instructions. The insertion torque value (ITV), implant stability quotient (ISQ), and removal torque value (RTV) were recorded as indicators of primary implant stability. Significant correlations and linear relationships were found between the CT value and ITV, ISQ, and RTV for both straight and tapered implants (Spearman's correlation coefficient, p quantitatively estimated using the CT value preoperatively, indicating the CT value of bone surrounding an implant can contribute considerably to implant planning and design choice in clinical situations. © 2014 Wiley Periodicals, Inc.

  2. Clinical evaluation of ridge augmentation using autogenous tooth bone graft material: case series study.

    Science.gov (United States)

    Lee, Ji-Young; Kim, Young-Kyun; Yi, Yang-Jin; Choi, Joon-Ho

    2013-08-01

    Interest in bone graft material has increased with regard to restoration in cases of bone defect around the implant. Autogenous tooth bone graft material was developed and commercialized in 2008. In this study, we evaluated the results of vertical and horizontal ridge augmentation with autogenous tooth bone graft material. This study targeted patients who had vertical or horizontal ridge augmentation using AutoBT from March 2009 to April 2010. We evaluated the age and gender of the subject patients, implant stability, adjunctive surgery, additional bone graft material and barrier membrane, post-operative complication, implant survival rate, and crestal bone loss. We performed vertical and horizontal ridge augmentation using powder- or block-type autogenous tooth bone graft material, and implant placement was performed on nine patients (male: 7, female: 2). The average age of patients was 49.88±12.98 years, and the post-operative follow-up period was 35±5.31 months. Post-operative complications included wound dehiscence (one case), hematoma (one case), and implant osseointegration failure (one case; survival rate: 96%); however, there were no complications related to bone graft material, such as infection. Average marginal bone loss after one-year loading was 0.12±0.19 mm. Therefore, excellent clinical results can be said to have been obtained. Excellent clinical results can be said to have been obtained with vertical and horizontal ridge augmentation using autogenous tooth bone graft material.

  3. Comparison of bone histomorphometry and μCT for evaluating bone quality in tail-suspended rats

    Science.gov (United States)

    Sun, Lian-Wen; Huang, Yun-Fei; Wang, Ying; Luan, Hui-Qin; Fan, Yu-Bo

    2014-10-01

    Astronauts often suffer from microgravity-induced osteoporosis due to their time in space. Bone histomorphometry, the 'gold standard' technique for detecting bone quality, is widely used in the evaluation of osteoporosis. This study investigates whether μCT has the same application value as histomorphometry in the evaluation of weightlessness-induced bone loss. A total of 24 SD rats were distributed into three groups (n = 8, each): tail-suspension (TS), TS plus active exercise (TSA), and control (CON). After 21 days, bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) and μCT, and microstructure was measured by μCT and histomorphometry. BMD was found to have decreased significantly in TS and TSA compared with the CON group. The results of the μCT measurements showed that a change in BMD mainly occurred in the trabecular bone, and the trabecular BMD increased significantly in the TSA compared with the TS group. The comparison of μCT and histomorphometry showed that TS led to a significant decrease in bone volume (BV/TV), trabecular thickness (Tb.Th) and trabecular number (Tb.N), and it led to an increase in trabecular separation (Tb.Sp). However, active exercise can prevent these changes. Significant differences in most parameters between TSA and CON were found by μCT but not by histomorphometry. Additionally, the parameters of these two methods are highly correlated. Therefore, the application value of μCT is as good as histomorphometry and DXA in the diagnosis of weightlessness-induced osteoporosis and is even better in evaluating the efficacy of exercise.

  4. Developing and Evaluating a Flexible Wireless Microcoil Array Based Integrated Interface for Epidural Cortical Stimulation

    Directory of Open Access Journals (Sweden)

    Xing Wang

    2017-02-01

    Full Text Available Stroke leads to serious long-term disability. Electrical epidural cortical stimulation has made significant improvements in stroke rehabilitation therapy. We developed a preliminary wireless implantable passive interface, which consists of a stimulating surface electrode, receiving coil, and single flexible passive demodulated circuit printed by flexible printed circuit (FPC technique and output pulse voltage stimulus by inductively coupling an external circuit. The wireless implantable board was implanted in cats’ unilateral epidural space for electrical stimulation of the primary visual cortex (V1 while the evoked responses were recorded on the contralateral V1 using a needle electrode. The wireless implantable board output stable monophasic voltage stimuli. The amplitude of the monophasic voltage output could be adjusted by controlling the voltage of the transmitter circuit within a range of 5–20 V. In acute experiment, cortico-cortical evoked potential (CCEP response was recorded on the contralateral V1. The amplitude of N2 in CCEP was modulated by adjusting the stimulation intensity of the wireless interface. These results demonstrated that a wireless interface based on a microcoil array can offer a valuable tool for researchers to explore electrical stimulation in research and the dura mater-electrode interface can effectively transmit electrical stimulation.

  5. Developing and Evaluating a Flexible Wireless Microcoil Array Based Integrated Interface for Epidural Cortical Stimulation

    Science.gov (United States)

    Wang, Xing; Chaudhry, Sharjeel A.; Hou, Wensheng; Jia, Xiaofeng

    2017-01-01

    Stroke leads to serious long-term disability. Electrical epidural cortical stimulation has made significant improvements in stroke rehabilitation therapy. We developed a preliminary wireless implantable passive interface, which consists of a stimulating surface electrode, receiving coil, and single flexible passive demodulated circuit printed by flexible printed circuit (FPC) technique and output pulse voltage stimulus by inductively coupling an external circuit. The wireless implantable board was implanted in cats’ unilateral epidural space for electrical stimulation of the primary visual cortex (V1) while the evoked responses were recorded on the contralateral V1 using a needle electrode. The wireless implantable board output stable monophasic voltage stimuli. The amplitude of the monophasic voltage output could be adjusted by controlling the voltage of the transmitter circuit within a range of 5–20 V. In acute experiment, cortico-cortical evoked potential (CCEP) response was recorded on the contralateral V1. The amplitude of N2 in CCEP was modulated by adjusting the stimulation intensity of the wireless interface. These results demonstrated that a wireless interface based on a microcoil array can offer a valuable tool for researchers to explore electrical stimulation in research and the dura mater-electrode interface can effectively transmit electrical stimulation. PMID:28165427

  6. An automatic early stage alveolar-bone-resorption evaluation method on digital dental panoramic radiographs

    Science.gov (United States)

    Zhang, Min; Katsumata, Akitoshi; Muramatsu, Chisako; Hara, Takeshi; Suzuki, Hiroki; Fujita, Hiroshi

    2014-03-01

    Periodontal disease is a kind of typical dental diseases, which affects many adults. The presence of alveolar bone resorption, which can be observed from dental panoramic radiographs, is one of the most important signs of the progression of periodontal disease. Automatically evaluating alveolar-bone resorption is of important clinic meaning in dental radiology. The purpose of this study was to propose a novel system for automated alveolar-bone-resorption evaluation from digital dental panoramic radiographs for the first time. The proposed system enables visualization and quantitative evaluation of alveolar bone resorption degree surrounding the teeth. It has the following procedures: (1) pre-processing for a test image; (2) detection of tooth root apices with Gabor filter and curve fitting for the root apex line; (3) detection of features related with alveolar bone by using image phase congruency map and template matching and curving fitting for the alveolar line; (4) detection of occlusion line with selected Gabor filter; (5) finally, evaluation of the quantitative alveolar-bone-resorption degree in the area surrounding teeth by simply computing the average ratio of the height of the alveolar bone and the height of the teeth. The proposed scheme was applied to 30 patient cases of digital panoramic radiographs, with alveolar bone resorption of different stages. Our initial trial on these test cases indicates that the quantitative evaluation results are correlated with the alveolar-boneresorption degree, although the performance still needs further improvement. Therefore it has potential clinical practicability.

  7. Bone mineral measurements of subchondral and trabecular bone in healthy and osteoporotic rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Castaneda, S [Universidad Autonoma, Rheumatology Department, Hospital de la Princesa, Madrid (Spain); Largo, R.; Marcos, M.E.; Herrero-Beaumont, G. [Universidad Autonoma, Inflammation Research Unit, Rheumatology Department, Fundacion Jimenez Diaz, Madrid (Spain); Calvo, E. [Universidad Autonoma, Inflammation Research Unit, Rheumatology Department, Fundacion Jimenez Diaz, Madrid (Spain); Universidad Autonoma, Department of Orthopaedic Surgery, Fundacion Jimenez Diaz, Madrid (Spain); Rodriguez-Salvanes, F. [Universidad Autonoma, Clinical Epidemiology Unit, Hospital de la Princesa, Madrid (Spain); Diaz-Curiel, M. [Universidad Autonoma, Department of Internal Medicine, Fundacion Jimenez Diaz, Madrid (Spain)

    2006-01-01

    Experimental models of osteoporosis in rabbits are useful to investigate anabolic agents because this animal has a fast bone turnover with predominant remodelling over the modelling processes. For that purpose, it is necessary to characterize the densitometric values of each type of bony tissue. To determine areal bone mass measurement in the spine and in trabecular, cortical and subchondral bone of the knee in healthy and osteoporotic rabbits. Bone mineral content and bone mineral density were measured in lumbar spine, global knee, and subchondral and cortical bone of the knee with dual energy X-ray absorptiometry using a Hologic QDR-1000/W densitometer in 29 skeletally mature female healthy New Zealand rabbits. Ten rabbits underwent triplicate scans for evaluation of the effect of repositioning. Osteoporosis was experimentally induced in 15 rabbits by bilateral ovariectomy and postoperative corticosteroid treatment for 4 weeks. Identical dual energy X-ray absorptiometry (DXA) studies were performed thereafter. Mean values of bone mineral content at the lumbar spine, global knee, subchondral bone and cortical tibial metaphysis were: 1934{+-}217 mg, 878{+-}83 mg, 149{+-}14 mg and 29{+-}7.0 mg, respectively. The mean values of bone mineral density at the same regions were: 298{+-}24 mg/cm{sup 2}, 455{+-}32 mg/cm{sup 2}, 617{+-}60 mg/cm{sup 2} and 678{+-}163 mg/cm{sup 2}, respectively. (orig.)

  8. Multi-frequency axial transmission bone ultrasonometer.

    Science.gov (United States)

    Tatarinov, Alexey; Egorov, Vladimir; Sarvazyan, Noune; Sarvazyan, Armen

    2014-07-01

    The last decade has seen a surge in the development of axial transmission QUS (Quantitative UltraSound) technologies for the assessment of long bones using various modes of acoustic waves. The condition of cortical bones and the development of osteoporosis are determined by numerous mechanical, micro-structural, and geometrical or macro-structural bone properties like hardness, porosity and cortical thickness. Such complex manifestations of osteoporosis require the evaluation of multiple parameters with different sensitivities to the various properties of bone that are affected by the disease. This objective may be achieved by using a multi-frequency ultrasonic examination The ratio of the acoustic wavelength to the cortical thickness can be changed by varying the frequency of the ultrasonic pulse propagating through the long bone that results in the change in composition of the induced wave comprised of a set of numerous modes of guided, longitudinal, and surface acoustic waves. The multi-frequency axial transmission QUS method developed at Artann Laboratories (Trenton, NJ) is implemented in the Bone Ultrasonic Scanner (BUSS). In the current version of the BUSS, a train of ultrasonic pulses with 60, 100, 400, 800, and 1200 kHz frequencies is used. The developed technology was tested on a variety of bone phantoms simulating normal, osteopenic, and osteoporotic bones. The results of this study confirm the feasibility of the multi-frequency approach for the assessment of the processes leading to osteoporosis.

  9. Bone marrow scan evaluation of arthropathy in sickle cell disorders

    Energy Technology Data Exchange (ETDEWEB)

    Alavi, A.; Schumacher, H.R.; Dorwart, B.; Kuhl, D.E.

    1976-04-01

    Twelve patients with sickle cell hemoglobinopathies and arthropathy were studied, using technetium Tc 99m sulfur colloid bone marrow scans. Eight of 12 had decreased marrow radionuclide activity adjacent to painful joints, suggesting obliteration of vessels supplying bone marrow. Four patients without marrow defects on scanning had causes other than infarction for their joint symptoms, viz, small fractures, postinfectious synovitis, degenerative arthritis, and osteochondromas. Roentgenograms never showed bony abnormalities in five patients with marrow infarctions, and, in three others, showed defects several months later than did the marrow scans. Bone marrow scans offer a sensitive and early diagnostic aid in sickle cell hemoglobinopathies with arthropathy.

  10. Evaluating differential nuclear DNA yield rates and osteocyte numbers among human bone tissue types: A synchrotron radiation micro-CT approach.

    Science.gov (United States)

    Andronowski, Janna M; Mundorff, Amy Z; Pratt, Isaac V; Davoren, Jon M; Cooper, David M L

    2017-05-01

    Molecular human identification has conventionally focused on DNA sampling from dense, weight-bearing cortical bone tissue, typically from femora or tibiae. A comparison of skeletal elements from three contemporary individuals demonstrated that elements with high quantities of cancellous bone yielded nuclear DNA at the highest rates, suggesting that preferentially sampling cortical bone may be suboptimal (Mundorff & Davoren, 2014). Despite these findings, the reason for the differential DNA yields between cortical and cancellous bone tissues remains unknown. The primary goal of this work is to ascertain whether differences in bone microstructure can be used to explain differential nuclear DNA yield among bone tissue types observed by Mundorff and Davoren (2014), with a focus on osteocytes and the three-dimensional (3D) quantification of their associated lacunae. Osteocytes and other bone cells are recognized to house DNA in bone tissue, thus examining the density of their lacunae may explain why nuclear DNA yield rates differ among bone tissue types. Lacunae were visualized and quantified using synchrotron radiation-based micro-Computed Tomographic imaging (SR micro-CT). Volumes of interest (VOIs) from cortical and cancellous bone tissues (n=129) were comparatively analyzed from the three skeletons sampled for Mundorff and Davoren's (2014) study. Analyses tested the primary hypothesis that the abundance and density of osteocytes (inferred from their lacunar spaces) vary between cortical and cancellous bone tissue types. Results demonstrated that osteocyte lacunar abundance and density vary between cortical and cancellous bone tissue types, with cortical bone VOIs containing a higher lacunar abundance and density. We found that the osteocyte lacunar density values are independent of nuclear DNA yield, suggesting an alternative explanation for the higher nuclear DNA yields from bones with greater quantities of cancellous bone tissue. The use of SR micro-CT allowed for

  11. [Evaluation of multiple myeloma with bone scintigraphy using Tc 99 diphosphonate. Review of the literature].

    Science.gov (United States)

    Solis, O J; Gonzales, R; De Luca, S; McKusick, K A; Potsaid, M S

    1977-04-01

    Bone Scanning using 99m Tc-Diphosphonate is another diagnostic modality in the evaluation of multiple mieloma which allows the identification of bone lesions not demonstrable by conventional radiography. The use of 99m Tc-Diphosphonate is more convenient and less harmful than other radioactive isotopes utilized before.

  12. [Encounter of cancer cells with bone. Therapy for bone metastasis from lung cancer].

    Science.gov (United States)

    Sugiura, Hideshi

    2011-03-01

    Bone metastasis from lung cancer requires a thorough examination of bones, including axial bones (e.g., spine, pelvis, and proximal femur) . Most patients have multiple bone metastases by the time they are initially diagnosed. In such patients, radiation therapy is often the first choice of treatment. Surgical treatment is indicated for pathological fracture and impending fracture associated with cortical bone invasion in long bone metastasis. Spinal metastasis requires accurate imaging to evaluate the extent of bone metastasis ; surgical treatment is indicated when the spinal cord is compressed. Given reports that bisphosphonates decrease the incidence of pathological fractures, prescribing bisphosphonates at an early stage is likely to be an effective therapeutic strategy for bone metastasis.

  13. [Cortical blindness].

    Science.gov (United States)

    Chokron, S

    2014-02-01

    Cortical blindness refers to a visual loss induced by a bilateral occipital lesion. The very strong cooperation between psychophysics, cognitive psychology, neurophysiology and neuropsychology these latter twenty years as well as recent progress in cerebral imagery have led to a better understanding of neurovisual deficits, such as cortical blindness. It thus becomes possible now to propose an earlier diagnosis of cortical blindness as well as new perspectives for rehabilitation in children as well as in adults. On the other hand, studying complex neurovisual deficits, such as cortical blindness is a way to infer normal functioning of the visual system.

  14. Evaluation of techniques for human bone decalcification and amplification using sixteen STR markers

    Directory of Open Access Journals (Sweden)

    Ajay Balayan

    2015-03-01

    Full Text Available Efficient DNA extraction procedures, as well as accurate DNA amplification, are critical steps involved in the process of successful DNA analysis of skeletal samples. Unfortunately, at present there is no infallible method to recover DNA from highly degrad