Sample records for disc arthroplasty devices

  1. Cervical Total Disc Arthroplasty

    Basho, Rahul; Hood, Kenneth A.


    Symptomatic adjacent segment degeneration of the cervical spine remains problematic for patients and surgeons alike. Despite advances in surgical techniques and instrumentation, the solution remains elusive. Spurred by the success of total joint arthroplasty in hips and knees, surgeons and industry have turned to motion preservation devices in the cervical spine. By preserving motion at the diseased level, the hope is that adjacent segment degeneration can be prevented. Multiple cervical disc...

  2. Lubrication regimes in lumbar total disc arthroplasty.

    Shaheen, A; Shepherd, D E T


    A number of total disc arthroplasty devices have been developed. Some concern has been expressed that wear may be a potential failure mode for these devices, as has been seen with hip arthroplasty. The aim of this paper was to investigate the lubrication regimes that occur in lumbar total disc arthroplasty devices. The disc arthroplasty was modelled as a ball-and-socket joint. Elastohydrodynamic lubrication theory was used to calculate the minimum film thickness of the fluid between the bearing surfaces. The lubrication regime was then determined for different material combinations, size of implant, and trunk velocity. Disc arthroplasties with a metal-polymer or metal-metal material combination operate with a boundary lubrication regime. A ceramic-ceramic material combination has the potential to operate with fluid-film lubrication. Disc arthroplasties with a metal-polymer or metal-metal material combination are likely to generate wear debris. In future, it is worth considering a ceramic-ceramic material combination as this is likely to reduce wear.

  3. Lumbar disc arthroplasty with Maverick disc versus stand-alone interbody fusion: a prospective, randomized, controlled, multicenter investigational device exemption trial.

    Gornet, Matthew F; Burkus, J Kenneth; Dryer, Randall F; Peloza, John H


    Randomized, controlled, multicenter, investigational device exemption trial. To investigate the safety and effectiveness of the first two-piece, metal-on-metal lumbar disc prosthesis for treating patients with single-level degenerative disc disease. For patients with degenerative disc disease unresponsive to conservative measures, lumbar disc arthroplasty provides an alternative to fusion designed to relieve persistent discogenic pain and maintain motion. After 2:1 randomization, 577 patients were treated in either the investigational group (405), receiving lumbar disc arthroplasty, or the control group (172), receiving anterior lumbar interbody fusion. Patients were evaluated preoperatively, at surgery/discharge, and at 1.5, 3, 6, 12, and 24 months after surgery. The primary study endpoint was overall success, a composite measure of safety and effectiveness as recommended by the Food and Drug Administration and defined in the protocol. Both treatment groups demonstrated significant improvements compared with preoperative status. The investigational group had statistically superior outcomes (P < 0.05) at all postoperative evaluations in Oswestry Disability Index, back pain, and Short Form-36 Physical Component Summary scores as well as patient satisfaction. Investigational patients had longer surgical times (P < 0.001) and greater blood loss (P < 0.001) than did control patients; however, hospitalization stays were similar for both groups. Investigational patients had fewer implant or implant/surgical procedure-related adverse events (P < 0.001). Return-to-work intervals were reduced for investigational patients. Disc height and segmental angular motion were maintained throughout the study in the investigational group. In the investigational group, overall success superiority was found when compared to the control group as defined by the Food and Drug Administration Investigational Device Exemption protocol. The investigational group consistently demonstrated

  4. Durability of cervical disc arthroplasties and its influence factors

    Chen, Chao; Zhang, Xiaolin; Ma, Xinlong


    Abstract Background: The durability of cervical disc arthroplasties (CDA) may vary significantly because of different designs and implanting techniques of the devices. Nevertheless, the comparative durability remains unknown. Objectives: We aimed to assess the durability of CDAs in at least 2-year follow-up. We analyzed the classifications and causes of secondary surgical procedures, as well as the structural designs of the devices that might influence the durability. Methods: PubMed, Medline, Embase, and Cochrane Central Register of Controlled Trials were searched from the inception of each database to September 2015 using the following Keywords: “cervical disc replacement” OR “cervical disc arthroplasty” AND “randomized controlled trial (RCT).” Publication language was restricted to English. The primary outcome was the rate of secondary surgical procedures following CDA or anterior cervical decompression and fusion (ACDF). Pairwise meta-analysis and a Bayesian network meta-analysis were carried out using Review Manager v5.3.5 and WinBUGS version 1.4.3, respectively. Quality of evidence was appraised by Grading of Recommendations Assessment, Development and Evaluation methodology. Results: Twelve RCTs that met the eligibility criteria were included. Follow-up ranged from 2 years to 7 years. A total of 103 secondary surgical procedures were performed. The most frequent classification of secondary surgical procedures was reoperation (48/103) and removal (47/103). Revision (3/103) and supplementary fixation (2/103) were rare. Adjacent-level diseases were the most common cause of reoperations. The rates of secondary surgical procedures were significantly lower in Mobi-C, Prestige, Prodisc-C, Secure-C group than in ACDF group. No significant difference was detected between Bryan, PCM, Kineflex-C, Discover, and ACDF. Mobi-C, Secure-C, and Prodisc-C ranked the best, the second best, the third best, respectively. Conclusions: We concluded that Mobi-C, Secure

  5. Cervical disc arthroplasty with ProDisc-C artificial disc: 5-year radiographic follow-up results

    ZHAO Yan-bin; SUN Yu; ZHOU Fei-fei; LIU ZHONG-jun


    Background Cervical disc arthroplasty is an alternative surgery to standard cervical decompression and fusion for disc degeneration.Different types of cervical disc prosthesis are used in China.The aim of this study was to evaluate the radiographic outcomes of cervical arthroplasty using the ProDisc-C prosthesis.Methods Radiographic evaluation,including static and dynamic flexion-extension lateral images,was performed at baseline and at final follow-up.Results Twenty six patients who had single-level ProDisc-C arthroplasty were followed up for a mean period of 63 months (56-76 months).The range of motion at the operated level was 9.3°±3.7° at baseline and 7.3°±3.5° at final follow-up,with a significant difference (P <0.05).Seventeen of 26 levels (65.4%) developed heterotopic ossification:three were classified as grade Ⅱ,13 were classified as grade Ⅲ,and 1 as grade Ⅳ,according to McAfee's classification.Forty nine adjacent segments were evaluated by lateral Ⅹ-ray and 18 (36.7%) segments developed adjacent segment degenerations.Conclusions ProDisc-C arthroplasty had acceptable radiographic results at 5-year follow-up.The range of motion was preserved.However,more than 60% of the patients developed heterotopic ossification.

  6. Artificial Cervical Disc Arthroplasty (ACDA): tips and tricks

    Khadivi, Masoud; Rahimi Movaghar, Vafa; Abdollahzade, Sina


    Abstract: Background: Anterior cervical discectomy and fusion (ACDF) is currently treatment of choice for managing medical therapy refractory cervical degenerative disc disease. Numerous studies have demonstrated the effectiveness of ACDF; patients generally experience rapid recoveries, and dramatic improvement in their pain and quality of life. However, as several studies reported symptomatic adjacent segment disease attributed to fusions’ altered kinematics, cervical disc arthroplasty emerged as a new motion-sparing alternative to fusion. Fusion at one level increases motion at adjacent levels along with increased intradiscal pressures. This phenomenon can result in symptomatic adjacent level degeneration, which can necessitate reoperation at these levels. The era of cervical arthroplasty began in Europe in the late 1990s. In recent years, artificial cervical disc arthroplasty (ACDA) has been increasingly used by spine surgeons for degenerative cervical disc disease. There have been several reports of safety, efficacy and indications of ACDA. Cervical arthroplasty offers several theoretical advantages over anterior cervical discectomy and fusion (ACDF) in the treatment of selected patients with medically refractory cervical radiculopathy. Preserving motion at the operated level, cervical TDR has the potential to decrease the occurrence of adjacent segment degeneration. There are a few studies on the efficacy and effectiveness of ACDA compared to cervical fusion. However, the true scenery of cervical arthroplasty yet to be identified. Objective: This study is intended to define patients' characteristics and outcomes of ACDA by a single surgeon in Iran. Methods: This retrospective study was performed in two general Hospitals in Tehran, Iran from 2005 To 2010. All patients were operated by one senior neurospine surgeon. One hundred fifty three patients were operated in this period. All patients signed the informed consent form prior to surgery. All patients

  7. Subsidence and malplacement with the Oblique Maverick Lumbar Disc Arthroplasty: technical note.

    Marshman, Laurence A G; Friesem, Tai; Rampersaud, Y Raja; Le Huec, Jean-Charles; Krishna, Manoj


    The A-Mav (Medtronic, Sofamor Danek, Memphis, TN) is a well-established lumbar total disc arthroplasty device. The O-Mav (Medtronic) is a more recent innovation designed to minimize the potential vascular complications associated with A-Mav insertion at L4/5. No study has hitherto studied the relative accuracy or safety of the two techniques. To compare the accuracy of lumbar disc arthroplasty placement by using the anterior technique (A-Mav) with the oblique (O-Mav) technique. Technical report. Fourteen patients. Implant placement accuracy on high-resolution computed tomography scan. Comparative morbidity, mortality, blood loss, and operating time were also assessed. Patients were considered for lumbar disc arthroplasty who had suffered chronic discogenic low back pain unresponsive to nonoperative management for at least 6 months. All patients were operated on at the L4/5 level. A-Mavs were inserted in 7 patients and O-Mavs in 7. Implant placement was analyzed postoperatively by using computer software on high-resolution computed tomography scan with respect to four parameters: (1) off-center malplacement, (2) axial rotational malplacement, (3) coronal tilt, and (4) vertebral body susbsidence. Comparative morbidity, mortality, blood loss, and operating time were also assessed. Subsidence, off-center malplacement, and rotational malplacement were significantly increased in O-Mavs compared with A-Mavs (4.3+/-0.6 mm vs. 1.6+/-0.6 mm, p=.008; 3.1+/-0.4 mm vs. 1.3+/-0.4 mm, p=.006; 6.5 degrees +/-1.2 degrees vs. 3.8 degrees +/-0.4 degrees , p=.046). No significant differences were found between O-Mavs and A-Mavs in tilt, operating time, blood loss, or morbidity and mortality. O-Mav insertion appears to be complicated by significantly greater vertebral body subsidence and malplacement than A-Mav insertion. A-Mav insertion therefore appears to be more accurate and less complicated yet equally as safe as O-Mav insertion.

  8. Removal versus preservation of the posterior longitudinal ligament in Bryan cervical disc arthroplasty

    YANG Da-long; DING Wen-yuan; ZHANG Ying-ze; ZHANG Wei; XU Jia-xin; SHEN Yong


    Background Bryan cervical disc arthroplasty can be used to restore and maintain the mobility and function of the involved cervical spinal segments.The efficiency of posterior longitudinal ligament (PLL) resection in anterior cervical decompression and fusion has been demonstrated.However,no clinical reports have compared PLL removal with preservation in Bryan cervical disc arthroplasty.This study aimed to assess the role of removal of PLL in Bryan cervical disc arthroplasty at an 18-month follow-up.Methods We performed a prospective investigation of clinical and radiological outcomes in patients after Bryan cervical disc arthroplasty.Sixty patients who underwent Bryan cervical disc arthroplasty were included.The PLL was removed in 35 patients (investigational group) and preserved in 25 patients (control group).All of the patients were followed up for more than 18 months.Clinical (Japanese Orthopedic Association score and Visual Analogue Scale pain score) and radiological (functional spinal unit (FSU) angle,range of movement (ROM),and diameter of the spinal cord) parameters were compared between the two groups before and after surgery (18 months).Results Clinical outcomes in the investigational group were significantly superior to those in the control group.There were no significant differences in the FSU angle and ROM (P=-0.41 and 0.16,respectively) between the two groups.However,the increase in diameter of the spinal cord in the investigational group was significantly greater than that in the control group (P <0.01).Conclusions Removal of the PLL can improve the clinical outcomes of Bryan cervical disc arthroplasty.This procedure does not have a large effect on imbalance and motion of the cervical spine.

  9. Scaling from discs to pleated devices.

    Giglia, Sal; Yavorsky, David


    Membrane discs offer a convenient format for evaluating membrane performance in normal flow filtration. However, while pleated devices of different sizes tend to scale in close proportion to their contained areas, they do not necessarily scale in direct proportion from flat discs. The objectives of this study are to quantify differences in performance among sterilizing-grade membrane devices as a function of device type and size, to develop an understanding of the factors that affect device scalability, and to develop a mathematical model to predict a cartridge-to-disc scalability factor based on membrane properties and porous support properties and dimensions. Measured and predicted normalized water permeability scalability factors for seven types of pleated cartridges, including 0.1-micro and 0.2-micro rated PES, and 0.2-micro rated polyvinylidene fluoride (PVDF) sterilizing-grade filters in nominal 1-inch to 5-inch lengths, were determined. The results of this study indicate that pleated cartridge performance can be closely predicted based on 47-mm disc performance provided that a number of measured device parameters are properly accounted for, most importantly parasitic pressure losses in the filter device and plumbing connections, intrinsic membrane variability, true effective device filtration area, and the hydraulic properties of all porous support materials. Throughput scalability factors (discs to devices) tend to converge towards unity, especially for highly plugging streams. As the membrane fouls, the resistance through the membrane dominates other resistances, so the flux scales more linearly with membrane area and the overall scaling factor becomes close to one. The results of throughput tests on seven different cartridge types and five different challenge streams (with widely varying fouling characteristics) show that most of the throughput scaling factors were within +/-10% of 1.0. As part of this study, the effects of pressure and temperature were

  10. Cervical Disc Arthroplasty with Prestige LP Disc Versus Anterior Cervical Discectomy and Fusion: Seven-Year Outcomes.

    Gornet, Matthew F; Burkus, J Kenneth; Shaffrey, Mark E; Nian, Hui; Harrell, Frank E


    Cervical disc arthroplasty (CDA) has emerged as an alternative to anterior cervical discectomy and fusion (ACDF) for the treatment of cervical pathologies. Studies are on-going to assess the long term outcomes of CDA. This study assessed the safety and efficacy of the Prestige(®) LP Disc at 84-months follow up. Prospective data from 280 CDA patients with single-level cervical disc disease with radiculopathy or myelopathy were compared with 265 historical control ACDF patients. Clinical and radiographic follow up was completed pre-operatively, intraoperatively, and at intervals up to 84 months. Follow-up rate was 75.9% for CDA and 70.0% for ACDF patients. Statistical improvements (p Medtronic Spinal and Biologics, Memphis, TN. Study approved by the Hughston Sports Medicine Center Institutional Review Board on January 7, 2005. Clinical trial registered at NCT00667459. All participants signed an informed consent.

  11. The effect of single-level, total disc arthroplasty on sagittal balance parameters: a prospective study.

    Le Huec, Jc; Basso, Y; Mathews, H; Mehbod, A; Aunoble, S; Friesem, T; Zdeblick, T


    A prospective radiographic study of the influence of total disc replacement on spinal sagittal balance. The goal of this study was to prospectively determine the effect of a single-level, total disc replacement on the sagittal balance of the spine, especially on sacral tilt (ST), pelvic tilt (PT), and lumbar lordosis. It has been shown that lumbar fusion may deleteriously alter the sagittal balance of the spine, including a decrease in the ST and lumbar lordosis. Clinically, postfusion pain has been shown to be significantly related to a decreased ST, increased PT, and decreased lumbar lordosis, independent of other factors such as pseudoarthrosis. To our knowledge, the influence of total disc replacement on spinal sagittal balance has not yet been reported in the literature. This is a prospective study of 35 patients who received a single level disc replacement using the Maverick Total Disc Arthroplasty system (Medtronic Sofamor Danek, Memphis, Tennessee) by a single surgeon at one institution from March 2002 to September 2003. The preoperative and postoperative radiographic evaluation included standing anteroposterior and lateral full spine films that included the femoral heads. The parameters studied were ST, PT, global and segmental lordosis, and global kyphosis. The average age of the 35 patients studied was 44.3 years (range 35-57). There were 18 females and 17 males. The disc arthroplasty was performed at the L4-L5 level in 19 patients and at the L5-S1 level in 16 patients. The average follow-up was 14 months (range 6-22 months). The preoperative values of global lordosis, ST, and PT were 51.5 degrees , 37.8 degrees , 16.9 degrees and, at last follow-up, they were 51.4 degrees , 37.4 degrees , and 17.5 degrees , respectively. These changes were not significantly different. When the groups were separated according to the level operated, there was still no statistical difference with regard to the overall lordosis, ST, PT or kyphosis from pre- to postoperative

  12. Discover cervical disc arthroplasty versus anterior cervical discectomy and fusion in symptomatic cervical disc diseases: A meta-analysis

    Shangguan, Lei; Ning, Guang-Zhi; Tang, Yu; Wang, Zhe; Luo, Zhuo-Jing; Zhou, Yue


    Objective Symptomatic cervical disc disease (SCDD) is a common degenerative disease, and Discover artificial cervical disc, a new-generation nonconstrained artificial disk, has been developed and performed gradually to treat it. We performed this meta-analysis to compare the efficacy and safety between Discover cervical disc arthroplasty (DCDA) and anterior cervical discectomy and fusion (ACDF) for SCDD. Methods An exhaustive literature search of PubMed, EMBASE, and the Cochrane Library was conducted to identify randomized controlled trials that compared DCDA with ACDF for patients suffering SCDD. A random-effect model was used. Results were reported as standardized mean difference or risk ratio with 95% confidence interval. Results Of 33 articles identified, six studies were included. Compared with ACDF, DCDA demonstrated shorter operation time (P 0.05). Subgroup analyses did not demonstrated significant differences. Conclusion In conclusion, DCDA presented shorter operation time, and better ROM at the operative level. However, no significant differences were observed in blood loss, NDI scores, neck and arm pain scores, JOA scores, secondary surgery procedures and adverse events between the two groups. Additionally, more studies of high quality with mid- to long-term follow-up are required in future. PMID:28358860

  13. Lumbar total disc arthroplasty: coronal midline definition and optimal TDA placement.

    Marshman, Laurence A G; Friesem, Tai; Rampersaud, Y Raja; Le Huec, Jean-Charles; Krishna, Manoj; Reddy, Guru R


    It is a general principle with arthroplasty insertion that precise implant centering is critical for long term function and outcome. Whilst some authors have proclaimed that lumbar total disc arthroplasty (TDA) may be different, and that off -centre placement may be functionally well tolerated, these claims are premature: significantly worse clinical results have already been reported with poorly placed TDA at 2 years. Accurate TDA placement requires a precise and consistent definition of the desired coronal midline target (which is currently lacking), as well as a procedural mechanism to optimize placement at that target. We summarize our experience, as well as others', in achieving these two requirements. Long-term outcomes after lumbar TDA insertion should only be compared with results from fusion where TDAs have been implanted accurately.

  14. The Incidence of Adjacent Segment Degeneration after Cervical Disc Arthroplasty (CDA): A Meta Analysis of Randomized Controlled Trials

    Baohui Yang; Haopeng Li; Ting Zhang; Xijing He; Siyue Xu


    BACKGROUND: Cervical disc arthroplasty is being used as an alternative degenerative disc disease treatment with fusion of the cervical spine in order to preserve motion. However, whether replacement arthoplasty in the spine achieves its primary patient centered objective of lowering the frequency of adjacent segment degeneration is not verified yet. METHODOLOGY: We conducted a meta-analysis according to the guidelines of the Cochrane Collaboration using databases including PubMed, Cochrane Ce...

  15. Kinematics of cervical segments C5/C6 in axial rotation before and after total disc arthroplasty.

    Wachowski, Martin Michael; Weiland, Jan; Wagner, Markus; Gezzi, Riccardo; Kubein-Meesenburg, Dietmar; Nägerl, Hans


    The kinematical properties of C5/C6 segments in axial rotation are evaluated before and after total disc arthroplasty (TDA) with PRESTIGE(®)-and BRYAN(®) Cervical Disc (Medtronic) under flexion/extension as parameters and compared with those of C3/C4. Eight human segments were stimulated by triangularly varying, axially directed torque (T z(t)) under compressing static axial preloads. Using a 6D-measuring device with high resolution, the response of segmental motion was characterized by the instantaneous helical axis (IHA). The position, direction, and migration path length of the IHA were measured before and after TDA (parameter: position of the axially directed preload). The periodic torque T z(t) generated IHA migrations whereupon the IHA direction was constantly rotated to the dorsal by ≈15.5°. After TDA, the IHA0 (neutral positions) were significantly shifted to the dorsal (PRESTIGE(®): 4.3 mm, BRYAN(®): 7.0 mm) just as the points of balance of the entire IHA migration paths. Due to the configuration of the vertebral joints and their interaction with the intervertebral disc, the IHA migrates during the axial rotation within a distinct domain of each C5/C6-segment. Implantation of the PRESTIGE(®) and BRYAN(®) prostheses significantly alters these kinematical properties by dorsal displacements of the domains. Statistically TDA of C3/C4 and of C5/C6 are not correlated. Under axial rotation of the cervical spine, additional lateral and/or ventral/dorsal displacements are produced by TDA. Consequently, adjacent level disease (ALD) may be mechanically stimulated.

  16. Friction in metal-on-metal total disc arthroplasty: effect of ball radius.

    Moghadas, Parshia; Mahomed, Aziza; Hukins, David W L; Shepherd, Duncan E T


    Total disc arthroplasty (TDA) can be used to replace a degenerated intervertebral disc in the spine. There are different designs of prosthetic discs, but one of the most common is a ball-and-socket combination. Contact between the bearing surfaces can result in high frictional torque, which can then result in wear and implant loosening. This study was designed to determine the effects of ball radius on friction. Generic models of metal-on-metal TDA were manufactured with ball radii of 10, 12, 14 and 16 mm, with a radial clearance of 0.015 mm. A simulator was used to test each sample in flexion-extension, lateral bending and axial rotation at frequencies of 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75 and 2 Hz under loads of 50, 600, 1200 and 2000 N, in new born calf serum. Frictional torque was measured and Stribeck curves were plotted to illustrate the lubrication regime in each case. It was observed that implants with a smaller ball radius showed lower friction and showed boundary and mixed lubrication regimes, whereas implants with larger ball radius showed boundary lubrication only. This study suggests designing metal-on-metal TDAs with ball radius of 10 or 12 mm, in order to reduce wear and implant loosening. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Clinical and radiographic results of cervical artificial disc arthroplasty: over three years follow-up cohort study

    TIAN Wei; HAN Xiao; LIU Bo; LI Qin; HU Lin; LI Zhi-yu; YUAN Qiang; HE Da; XING Yong-gang


    Background Theoretic advantages of cervical disc arthroplasty include preservation of normal motion and biomechanics in the cervical spine, and reduction of adjacent-segment degeneration. The clinical and radiographic effects of cervical disc arthroplasty in short term have been ascertained. The aim of this study is to research the data of mid-term results.Methods In this prospective cohort study, 50 patients who underwent cervical disc arthroplasty from December 2003 to January 2006 were enrolled. There were 39 patients who received 1-level disc arthroplasty, and 11 patients received 2-level disc arthroplasty, with an average age of 50.9 years (range from 29 to 73). The median follow-up was 41.85months (range from 36.00-55.63 months). Patients were followed prospectively with respect to their symptoms,neurologic signs, and radiographic results.Results The median value of Japanese Orthopaedic Association (JOA) score was 14.0 before surgery, and 16.5 at the most recent follow-up (P <0.01). The median value of the recovery rate of the JOA score was 92.2%. The preoperative range of motion (ROM) at the indexed level was (10.40±4.97)°, which has significantly correlated with the most recent follow-up ROM which was (8.56±4.76)° (P <0.05, r=0.33). The ROM at the operative level at the most recent follow-upwas greater than the value at the 3-month follow-up of (7.52±3.37)° (P <0.05). The preoperative functional spinal unit (FSU) angulation was (-0.96±6.52)°, which was not significantly correlated with that of the most recent follow-up value of (-2.65±7.95)° (P <0.01, r=0.53). The preoperative endplate angulation was (2.61±4.85)°, which had no significant correlation with that of the most recent follow-up value of (0.71±6.41)° (p >0.05).Conclusions The clinical and radiographic results of cervical disc arthroplasty are good in mid-term follow-up. The normal range of motion of the operated level and the biomechanics in the cervical spine are well

  18. Comparison of single-level cervical fusion and a metal-on-metal cervical disc replacement device.

    Riina, Joseph; Patel, Amisha; Dietz, John W; Hoskins, Jeffery S; Trammell, Terry R; Schwartz, David D


    Cervical fusion is the common treatment for cervical disc disease but can cause secondary disorders. The Prestige ST cervical disc prosthesis (Medtronic Sofamor Danek, Memphis, TN) was designed to preserve spinal motion to potentially limit the secondary disorders. In this article, we report 2-year results from a single-center study comparing use of this device with use of anterior cervical discectomy and fusion (ACDF). Nineteen patients were prospectively randomized to receive the device or to undergo ACDF. Twenty-four months after surgery, patients who received the device demonstrated improvement in neck pain, arm pain, and neurologic function. In our cohort, patients who underwent arthroplasty demonstrated greater improvement in neurologic function and neck pain than patients who underwent cervical discectomy and fusion.

  19. Are PEEK-on-Ceramic Bearings an Option for Total Disc Arthroplasty? An In Vitro Tribology Study.

    Siskey, Ryan; Ciccarelli, Lauren; Lui, Melissa K C; Kurtz, Steven M


    endplates were the primary sources of wear and demonstrated an abrasive wear mechanism. Under idealized and impingement conditions, the ceramic core also demonstrated slight polishing of the articulating surface but the change in mass was unmeasurable. During abrasive testing, the titanium transfer on the core was shown to polish over 5 MC of testing. In all cases and consistent with previous studies of other PEEK bearing couples, the particle size was primarily ceramic wear rate (0.7 ± 0.1 mm(3)/MC) appears comparable to the published wear rates for other polymer-on-hard bearing couples (0.3-6.7 mm(3)/MC) and within the range of 0.2 to 1.9 mm(3)/MC reported for PEEK-on-PEEK cervical disc designs. The particles, based on size and morphology, also suggest the wear mechanism is comparable between the PEEK-on-ceramic couple and other polymer-on-ceramic orthopaedic couples. The PEEK-on-ceramic bearing considered in this study is a novel bearing couple for use in total disc arthroplasty devices and will require clinical evaluation to fully assess the bearing couple and total disc design. However, the wear rates under idealized and adverse conditions, and particle size and morphology, suggest that PEEK-on-ceramic bearings may be a reasonable alternative to polyethylene-on-CoCr and metal-on-metal bearings currently used in cervical TDRs.

  20. Impact of T1 slope on surgical and adjacent segment degeneration after Bryan cervical disc arthroplasty.

    Yang, Peng; Li, Yongqian; Li, Jia; Shen, Yong


    This retrospective study investigated an association between preoperative T1 slope and surgical and adjacent segment degeneration (SASD) after Bryan cervical disc arthroplasty (BCDA) in patients with cervical degenerative disc disease. Based on preoperative standing lateral radiographs, 90 patients were classified according to T1 slope that was higher or lower than the 50th percentile (high T1 or low T1, 28 and 62 patients, respectively). Patients were also classified as SASD or non-SASD (38 and 52 patients, respectively) determined by radiographs at final follow-up. Visual analog scale (VAS) and Neck Disability Index (NDI) scores for neck and arm pain were noted, and changes in the sagittal alignment of the cervical spine (SACS), functional spinal unit (FSU) angle, and FSU range of motion (ROM) were also noted. Univariate and multivariate logistic regression analyses were performed to determine the risk factors for SASD. The overall rate of SASD was 42.2% (38/90). The SACS, FSU angle, FSU ROM, and SASD rates of the high T1 and low T1 slope groups were significantly different at the last follow-up. The NDI and VAS scores of the high T1 slope group were significantly greater than those of the low T1 slope. The multivariate logistic regression analysis showed that high T1 slope and endplate coverage discrepancy (ie, residual space behind the prosthesis) were significant risk factors for SASD after BCDA. High T1 slope and endplate coverage discrepancy were associated with SASD after BCDA. Patients with a high preoperative T1 slope have a smaller FSU angle and more neck pain after BCDA.

  1. Clinical and radiographic analysis of cervical disc arthroplasty compared with allograft fusion: a randomized controlled clinical trial.

    Mummaneni, Praveen V; Burkus, J Kenneth; Haid, Regis W; Traynelis, Vincent C; Zdeblick, Thomas A


    The authors report the results of a prospective randomized multicenter study in which the results of cervical disc arthroplasty were compared with anterior cervical discectomy and fusion (ACDF) in patients treated for symptomatic single-level cervical degenerative disc disease (DDD). Five hundred forty-one patients with single-level cervical DDD and radiculopathy were enrolled at 32 sites and randomly assigned to one of two treatment groups: 276 patients in the investigational group underwent anterior cervical discectomy and decompression and arthroplasty with the PRESTIGE ST Cervical Disc System (Medtronic Sofamor Danek); 265 patients in the control group underwent decompressive ACDF. Eighty percent of the arthroplasty-treated patients (223 of 276) and 75% of the control patients (198 of 265) completed clinical and radiographic follow-up examinations at routine intervals for 2 years after surgery. Analysis of all currently available postoperative 12- and 24-month data indicated a two-point greater improvement in the neck disability index score in the investigational group than the control group. The arthroplasty group also had a statistically significant higher rate of neurological success (p = 0.005) as well as a lower rate of secondary revision surgeries (p = 0.0277) and supplemental fixation (p = 0.0031). The mean improvement in the 36-Item Short Form Health Survey Physical Component Summary scores was greater in the investigational group at 12 and 24 months, as was relief of neck pain. The patients in the investigational group returned to work 16 days sooner than those in the control group, and the rate of adjacent-segment reoperation was significantly lower in the investigational group as well (p = 0.0492, log-rank test). The cervical disc implant maintained segmental sagittal angular motion averaging more than 7 degrees. In the investigational group, there were no cases of implant failure or migration. The PRESTIGE ST Cervical Disc System maintained

  2. The incidence of adjacent segment degeneration after cervical disc arthroplasty (CDA: a meta analysis of randomized controlled trials.

    Baohui Yang

    Full Text Available BACKGROUND: Cervical disc arthroplasty is being used as an alternative degenerative disc disease treatment with fusion of the cervical spine in order to preserve motion. However, whether replacement arthoplasty in the spine achieves its primary patient centered objective of lowering the frequency of adjacent segment degeneration is not verified yet. METHODOLOGY: We conducted a meta-analysis according to the guidelines of the Cochrane Collaboration using databases including PubMed, Cochrane Central Register of Controlled Trials and Embase. The inclusion criteria were: 1 Randomized, controlled study of degenerative disc disease of the cervical spine involving single segment or double segments using Cervical disc arthroplasty (CDA with anterior cervical discectomy and fusion (ACDF as controls; 2 A minimum of two-year follow-up using imaging and clinical analyses; 3 Definite diagnostic evidences for "adjacent segment degeneration" and "adjacent segment disease"; 4 At least a minimum of 30 patients per population. Two authors independently selected trials; assessed methodological quality, extracted data and the results were pooled. RESULTS: No study has specifically compared the results of adjacent segment degenerative; Two papers describing 140 patients with 162 symptomatic cervical segment disorders and compared the rate of postoperative adjacent segment disease development between CDA and ACDF treatments, three publications describing the rate of adjacent-segment surgery including 1273 patients with symptomatic cervical segments. The result of the meta-analysis indicates that there were fewer the rate of adjacent segment disease and the rate for adjacent-segment surgery comparing CDA with ACDF, but the difference was not statistically significant. CONCLUSIONS: Based on available evidence, it cannot be concluded, that CDA can significantly reduce the postoperative rate of the adjacent segment degenerative and adjacent segment disease. However, due

  3. Cervical disc arthroplasty: do conflicts of interest influence the outcome of clinical studies?

    Narain, Ankur S; Hijji, Fady Y; Yom, Kelly H; Kudaravalli, Krishna T; Singh, Kern


    Cervical disc arthroplasty (CDA) is an emerging technique for the treatment of cervical degenerative disease. Multiple studies have investigated the outcomes of CDA, particularly in comparison with cervical arthrodesis techniques such as anterior cervical discectomy and fusion (ACDF). As many entities have financial interests in CDA implants, it is imperative to consider the influence of conflicts of interest on the results of studies investigating the efficacy of CDA. This study aimed to determine if there is an association between the presence of conflicts of interest among study authors and the reported outcome of studies involving CDA. This is a systematic review of clinical CDA publications until October 2016. The outcome measures are presence of conflicts of interest, level of evidence, and outcome for all included studies. PubMed and MEDLINE databases were searched for articles presenting clinical, radiographic, and cost outcomes of CDA. Data extracted from each article included title, authors, publication year, level of evidence, prosthesis type, number of operative levels, presence of conflicts of interest, and outcome. Conflicts of interest were determined by the presence of any conflicts for any author within manuscript disclosure sections or through Open Payments reporting. Outcomes of each study were graded as either favorable, unfavorable, or equivocal. The presence of conflicts of interest was tested for an association with the level of evidence and study outcome using Pearson chi-square analysis, Fisher exact test, or logistic regression for categorical variables. The authors report no conflicts of interest directly related to this work, and have not received any funds in support of this work. A total of 98 articles were included in this analysis. In total, 44.9% (44) of articles had the presence of a conflict of interest, whereas 55.1% (54) of articles did not. Conflicted studies were more likely to present level I evidence and less likely to

  4. Cervical disc arthroplasty compared with fusion in a workers' compensation population.

    Steinmetz, Michael P; Patel, Rakesh; Traynelis, Vincent; Resnick, Daniel K; Anderson, Paul A


    Patients with cervical radiculopathy and/or myelopathy are often treated with anterior cervical discectomy and fusion. Cervical arthroplasty has recently been advocated as an alternative treatment. Theoretically, arthroplasty should permit early return to activity and protect against adjacent segment disease. Early mobilization and return to activity may, theoretically, reduce cost to the workers' compensation program. A subgroup analysis of workers' compensation patients from the randomized controlled trials comparing Prestige ST and Bryan (Medtronic Sofamor Danek, Memphis, TN) cervical arthroplasty to fusion was performed. Primary outcome measures were work status, time to return to work, and neck disability. Secondary outcome measures were neck and arm pain and Medical Outcomes Study Short-Form 36-Item Health Survey score. One thousand four patients were enrolled in the studies, 93 of whom were workers' compensation patients. At 6 weeks and 3 months, significantly more patients in the arthroplasty group were working compared with the fusion group. At 6 months and later, there was no significant difference in return-to-work rates. Overall, patients returned to work at a median of 101 days after arthroplasty, compared with 222 days after anterior cervical discectomy and fusion. This difference was not significant when controlling for sex, study, and preoperative work status. At all time points, the Neck Disability Index was consistently lower in the arthroplasty group compared with the fusion group; however, the difference was not significant at 24 months. There was no statistically significant difference in secondary outcomes, neurological events, or pain-related events. In this workers' compensation cohort, it was observed that a greater number of patients in the arthroplasty group returned to work at 6 weeks and 3 months after surgery. A trend toward an earlier return to work was also seen, although this was not statistically significant when controlling for

  5. Application of cervical arthroplasty with Bryan cervical disc:long-term X-ray and magnetic resonance imaging follow-up results

    ZHAO Yan-bin; SUN Yu; CHEN Zhong-qiang; LIU Zhong-jun


    Background Cervical disc arthroplasty is a new technique for treating degenerative cervical disease. Its goal is to avoid the degeneration of adjacent levels by preserving motion at the treated level. The aims of this study were to evaluate the radiologic outcomes of Bryan cervical disc replacement and the degenerative status of adjacent segments.Methods Twenty-two patients at a single center underwent discectomy and implantation of Bryan cervical disc. The mean follow-up period was 60 months (57-69 months). Twenty patients underwent single-level arthroplasty and two underwent arthroplasty at two levels. The levels of surgery included C3/4 (3 levels), C4/5 (2 levels), C5/6 (18 levels) and C6/7 (1 level). Radiographic evaluation included dynamic X-ray examination and magnetic resonance imaging (MRI) at baseline and at final follow-up.Results On X-ray examination, the range of motion (ROM) at the operated level was 7.2° (2.5°-13.0°) at baseline and 7.8° (1.0°-15.0°) at final follow-up (P >0.05). Heterotopic ossification around the prosthesis was observed in eight levels,and two levels showed loss of motion (ROM <2°). MRI showed worsening by a grade at the upper level in 2/22 patients,and worsening by a grade at the lower level in 3/22, according to Miyazaki's classification. No further impingement of the ligamentum flavum into the spinal canal was observed at adjacent levels, though the disc bulge was slightly increased at both the adjacent upper and lower levels at final follow-up.Conclusions Arthroplasty using Bryan cervical disc prosthesis resulted in favorable radiologic outcomes in this study.Disc degeneration at adjacent levels may be postponed by this technique.

  6. Does total disc arthroplasty in C3/C4-segments change the kinematic features of axial rotation?

    Wachowski, Martin Michael; Wagner, Markus; Weiland, Jan; Dörner, Jochen; Raab, Björn Werner; Dathe, Henning; Gezzi, Riccardo; Kubein-Meesenburg, Dietmar; Nägerl, Hans


    We analyze how kinematic properties of C3/C4-segments are modified after total disc arthroplasty (TDA) with PRESTIGE(®) and BRYAN(®) Cervical Discs. The measurements were focused on small ranges of axial rotation (TDA. External parameters: constant axially directed pre-load, constant flexional/extensional and lateral-flexional pre-torque. The applied axial torque and IHA-direction did not run parallel. The IHA-direction was found to be rotated backwards and largely independent of the rotational angle, amount of axial pre-load, size of pre-torque, and TDA. In the intact segments pre-flexion/extension hardly influenced IHA-positions. After TDA, IHA-position was shifted backwards significantly (BRYAN-TDA: ≈8mm; PRESTIGE-TDA: ≈6mm) and in some segments laterally as well. Furthermore it was significantly shifted ventrally by pre-flexion and dorsally by pre-extension. The rate of lateral IHA-migration increased significantly after BRYAN-TDA during rightward or leftward rotations. In conclusion after the TDA the IHA-positions shifted backwards with significant increase in variability of the IHA-positions after the BRYAN-TDA more than in PRESTIGE-TDA. The TDA-procedure altered the segment kinematics considerably. TDA causes additional translations of the vertebrae, which superimpose the kinematics of the adjacent levels. The occurrence of adjacent level disease (ALD) is not excluded after the TDA for kinematical reasons.

  7. 78 FR 36573 - Certain Digital Media Devices, Including Televisions, Blu-Ray Disc Players, Home Theater Systems...


    ... COMMISSION Certain Digital Media Devices, Including Televisions, Blu-Ray Disc Players, Home Theater Systems... importation of certain digital media devices, including televisions, blu-ray disc players, home theater... after importation of certain digital media devices, including televisions, blu-ray disc players,...

  8. 78 FR 29156 - Certain Digital Media Devices, Including Televisions, Blu-Ray Disc Players, Home Theater Systems...


    ... COMMISSION Certain Digital Media Devices, Including Televisions, Blu-Ray Disc Players, Home Theater Systems... complaint entitled Certain Digital Media Devices, Including Televisions, Blu-Ray Disc Players, Home Theater... importation of certain digital media devices, including televisions, blu-ray disc players, home...

  9. Chiropractic management of patients post-disc arthroplasty: eight case reports

    Descarreaux Martin


    Full Text Available Abstract Background When conservative therapies for low back pain (LBP are not effective, elective surgery may be proposed to these patients. Over the last 20 years, a new technology, disc replacement, has become increasingly popular because it is believed to maintain or restore the integrity of spinal movement and minimize the side-effects compared to fusion. Although disc replacement may relieve a patient from pain and related disability, soreness and stiffness of the lumbopelvic region seem to be common aftermaths of the surgery. This prospective case series was undertaken to identify and describe potential adverse events of lumbar spinal manipulation, a common therapy for low back pain, in a group of patients with symptoms after disc prostheses. Cases presentation Eight patients who underwent lumbar spine total disc replacement were referred by an orthopaedic surgeon for chiropractic treatments. These patients had 1 or 2 total lumbar disc replacements and were considered stable according to the surgical protocol but presented persistent, post-surgical, non-specific LBP or pelvic pain. They were treated with lumbar spine side posture manipulations only and received 8 to 10 chiropractic treatments based on the clinical evolution and the chiropractor's judgment. Outcome measures included benign, self-limiting, and serious adverse events after low back spinal manipulative therapy. The Oswestry Disability Index, a pain scale and the fear avoidance belief questionnaire were administered to respectively assess disability, pain and fear avoidance belief about work and physical activity. This prospective case series comprised 8 patients who all had at least 1 total disc replacement at the L4/L5 or L5/S1 level and described persistent post-surgical LBP interfering with their daily activities. Commonly-reported side-effects of a benign nature included increased pain and/or stiffness of short duration in nearly half of the chiropractic treatment period

  10. Effect of prosthesis endplate lordosis angles on L5-S1 kinematics after disc arthroplasty.

    Tsitsopoulos, Parmenion P; Wojewnik, Bartosz; Voronov, Leonard I; Havey, Robert M; Renner, Susan M; Zelenakova, Julia; McIntosh, Braden; Carandang, Gerard; Abjornson, Celeste; Patwardhan, Avinash G


    We hypothesized that L5-S1 kinematics will not be affected by the lordosis distribution between the prosthesis endplates. Twelve cadaveric lumbosacral spines (51.3 ± 9.8 years) were implanted with 6° or 11° prostheses (ProDisc-L) with four combinations of superior/inferior lordosis (6°/0°, 3°/3°, 11°/0°, 3°/8°). Specimens were tested intact and after prostheses implantation with different lordosis distributions. Center of rotation (COR) and range of motion (ROM) were quantified. Six-degree lordosis prostheses (n = 7) showed no difference in flexion-extension ROM, regardless of design (6°/0° or 3°/3°) (p > 0.05). In lateral bending (LB), both designs reduced ROM (p lordosis prostheses (n = 5) showed no difference in flexion-extension ROM for either design (p > 0.05). LB ROM decreased with distributed lordosis prostheses (3°/8°) (p lordosis distribution among the two prosthesis endplates. The ProDisc-L prosthesis design where all lordosis is concentrated in the superior endplate yielded COR locations that were anterior and caudal to intact controls. The prosthesis with lordosis distributed between the two endplates yielded a COR that tended to be closer to intact. Further clinical and biomechanical studies are needed to assess the long-term impact of lordosis angle distribution on the fate of the facet joints.

  11. Mid- to Long-Term Outcomes of Cervical Disc Arthroplasty versus Anterior Cervical Discectomy and Fusion for Treatment of Symptomatic Cervical Disc Disease: A Systematic Review and Meta-Analysis of Eight Prospective Randomized Controlled Trials.

    Yan Hu

    Full Text Available This study aimed to investigate the mid- to long-term outcomes of cervical disc arthroplasty (CDA versus anterior cervical discectomy and fusion (ACDF for the treatment of 1-level or 2-level symptomatic cervical disc disease.Medline, Embase, and the Cochrane Central Register of Controlled Trials databases were searched to identify relevant randomized controlled trials that reported mid- to long-term outcomes (at least 48 months of CDA versus ACDF. All data were analyzed by Review Manager 5.3 software. The relative risk (RR and 95% confidence intervals (CIs were calculated for dichotomous variables. The weighted mean difference (WMD and 95%CIs were calculated for continuous variables. A random effect model was used for heterogeneous data; otherwise, a fixed effect model was used.Eight prospective randomized controlled trials (RCTs were retrieved in this meta-analysis, including 1317 and 1051 patients in CDA and ACDF groups, respectively. Patients after an ACDF had a significantly lower rate of follow-up than that after CDA. Pooled analysis showed patients in CDA group achieved significantly higher rates of overall success, Neck Disability Index (NDI success, neurological success and significantly lower rates of implant/surgery-related serious adverse events and secondary procedure compared with that in ACDF group. The long-term functional outcomes (NDI, Visual Analog Scale (VAS neck and arm pain scores, the Short Form 36 Health Survey physical component score (SF-36 PCS, patient satisfaction and recommendation, and the incidence of superior adjacent segment degeneration also favored patients in CDA group with statistical difference. Regarding inferior adjacent segment degeneration, patients in CDA group had a lower rate without statistical significance.This meta-analysis showed that cervical disc arthroplasty was superior over anterior discectomy and fusion for the treatment of symptomatic cervical disc disease in terms of overall success, NDI

  12. Prosthetic Lumbar disc replacement for degenerative disc disease

    Kulkarni Arvind


    Full Text Available Mechanical articulated device to replace intervertebral disc as a treatment for low back pain secondary to disc degeneration has emerged as a promising tool for selected patients. The potential advantages are prevention of adjacent segment degeneration, maintenance of mobility as well as avoidance of all the complications associated with fusion. The short-term results have been comparable to that of fusion, a few mid-term results have shown mixed outcome, but information on long-term results and performance are not available at present. The rationale for lumbar disc arthroplasty, indications, contraindications, the various artificial devices in the market and the concepts intrinsic to each of them, basic technique of insertion, complications are discussed and a brief summary of our experience with one of the devices is presented.

  13. 78 FR 56736 - Certain Digital Media Devices, Including Televisions, Blu-Ray Disc Players, Home Theater Systems...


    ... COMMISSION Certain Digital Media Devices, Including Televisions, Blu-Ray Disc Players, Home Theater Systems... digital media devices, including televisions, blu-ray disc players, home theater systems, tablets and... Hills Media, LLC (``BHM''). 78 FR 29156-57. The complaint alleges violations of section 337 of...

  14. Effect of lubricants on friction in laboratory tests of a total disc replacement device.

    Moghadas, Parshia; Mahomed, Aziza; Hukins, David W L; Shepherd, Duncan E T


    Some designs of total disc replacement devices have articulating bearing surfaces, and these devices are tested in vitro with a lubricant of diluted calf serum. It is believed that the lubricant found in total disc replacement devices in vivo is interstitial fluid that may have properties between that in Ringer's solution and diluted calf serum. To investigate the effect of lubricants, a set of friction tests were performed on a generic model of a metal against metal ball-and-socket total disc replacement device. Two devices were tested: one with a ball radius of 10 mm and other with a ball radius of 16 mm; each device had a radial clearance of 0.015 mm. A spine simulator was used to measure frictional torque for each device in axial rotation, flexion-extension and lateral bending at frequencies of 0.25-2 Hz, under 1200 N axial load. Each device was tested with two different lubricants: a solution of new born calf serum diluted with deionised water and Ringer's solution. The results showed that the frictional torque generated between the bearing surfaces was significantly higher in Ringer's solution than in diluted calf serum. The use of Ringer's solution as a lubricant provides a stringent test condition to detect possible problems. Diluted calf serum is more likely to provide an environment closer to that in vivo. However, the precise properties of the fluid lubricating a total disc replacement device are not known; hence, tests using diluted calf serum may not necessarily give the same results as those obtained in vivo.

  15. Maverick total disc arthroplasty performs well at 10 years follow-up: a prospective study with HRQL and balance analysis.

    Plais, N; Thevenot, X; Cogniet, A; Rigal, J; Le Huec, J C


    The treatment of low back pain associated to Disc Degenerative Disease (DDD) is still controversial. Segmental Fusion is the gold standard, but many studies have reported that motion-preserving devices bring substantial clinical benefits to patients. Concerns on the associated complications and on the long-term clinical effectiveness of such instrumentations are still present and have led recently to a decrease of the number of Lumbar Total Disk Replacements (TDR). The objective of this prospective study is to present the clinical and radiographic outcomes of the Maverick Lumbar disk prostheses (Medtronic, TE, Memphis, USA) at long-term follow-up. Prospective, single center study of clinical outcome of the treatment with Maverick lumbar Prosthesis of patients with low back pain from DDD resistant to conservative treatment. Patients were examined preoperatively and at 3 months, 2 and 10 years post-operatively. Patients were examined preoperatively and at 3 months, 2 and 10 years post-operatively. Visual analog scale (VAS), Oswestry disability index (ODI) and 36-Item Short Form Health Survey questionnaire were assessed to study clinical outcomes. Radiographic studies allowed measurements of range of motion, adjacent segment disease and pelvic and lumbar parameters. From an initial cohort of 87 patients who underwent TDR between 2003 and 2007 with the Maverick prosthesis, 61 were available at Final follow-up (70%). The clinical outcomes measured by VAS and ODI showed a significant improvement in all the postoperative stages of the follow-up (FU). At 10 years-FU, ODI experienced a mean decrease of 21.1 points, VAS for back pain decreased up to 3.85 and substantial clinical benefit was reached for 55.6% of the patients. Although Mobility of the prosthesis was preserved in 76.8% of the cases, TDR was not clearly protective against ALD. A significant, clinically relevant, and lasting reduction of back pain has been achieved in patients who underwent a total disk

  16. A new device used in the restoration of kinematics after total facet arthroplasty

    Vermesan D


    Full Text Available D Vermesan,1 R Prejbeanu,1 C Vlad Daliborca,1 H Haragus,1 M Magureanu,2 M Marrelli,3–5 L Promenzio,4 M Caprio,6 R Cagiano,6,* M Tatullo3,5,* 1Victor Babes University of Medicine and Pharmacy, Timisoara, 2Carol Davila University of Medicine and Pharmacy, Bucharest, Romania; 3Maxillofacial Unit, Dental Center Calabrodental, 4Orthopedics and Traumatology Unit, Marrelli Hospital, 5Biomedical Section, Tecnologica Research Institute, Crotone, 6Department of Biomedical Sciences and Human Oncology, Medical Faculty, Aldo Moro University of Bari, Bari, Italy *These authors contributed equally to this work Abstract: Facet degeneration can lead to spinal stenosis and instability, and often requires stabilization. Interbody fusion is commonly performed, but it can lead to adjacent-segment disease. Dynamic posterior stabilization was performed using a total facet arthroplasty system. The total facet arthroplasty system was originally intended to restore the natural motion of the posterior stabilizers, but follow-up studies are lacking due to limited clinical use. We studied the first 14 cases (long-term follow-up treated with this new device in our clinic. All patients were diagnosed with lumbar stenosis due to hypertrophy of the articular facets on one to three levels (maximum. Disk space was of normal height. The design of this implant allows its use only at levels L3–L4 and L4–L5. We implanted nine patients at the L4–L5 level and four patients at level L3–L4. Postoperative follow-up of the patients was obtained for an average of 3.7 years. All patients reported persistent improvement of symptoms, visual analog scale score, and Oswestry Disability Index score. Functional scores and dynamic radiographic imaging demonstrated the functional efficacy of this new implant, which represents an alternative technique and a new approach to dynamic stabilization of the vertebral column after interventions for spine decompression. The total facet arthroplasty

  17. Mobile compression devices and aspirin for VTE prophylaxis following simultaneous bilateral total knee arthroplasty.

    Nam, Denis; Nunley, Ryan M; Johnson, Staci R; Keeney, James A; Barrack, Robert L


    Recently, Levy et al questioned the effectiveness of mobile compression devices (MCDs) as the sole method of thromboprophylaxis following simultaneous bilateral total knee arthroplasty (TKA). This study's purpose was to assess if the addition of aspirin to MCDs improves venous thromboembolism (VTE) prevention following simultaneous bilateral TKA. Ninety-six patients (192 TKAs) were retrospectively reviewed: 47 patients received MCDs for 10 days and aspirin for 6 weeks postoperatively based on a risk stratification protocol, while 49 patients received warfarin for 4 weeks postoperatively. One symptomatic VTE was noted in the warfarin cohort, while one patient in the MCD/aspirin cohort and three patients in the warfarin cohort were readmitted within 3 months of surgery. In appropriately selected patients, MCDs with aspirin shows promise in VTE prevention following simultaneous bilateral TKA.

  18. The Research of Artificial Cervical Disc Replacement

    Zhao Zhua; Qiang Shenb


    Cervical arthroplasty after anterior decompression with insertion of a prosthetic total disc replacement has been suggested as an alternate to anterior cervical fusion. It develops quickly during recent years. Currently there are several cervical arthroplasty devices. Each device varies in terms of materials, range of motion and constraint. Early studies suggest that in the short term, the complication rate and efficacy is no worse than fusion surgery. Long-term results have not yet been reported. This review examines the current prostheses as well as discussing issues regarding indications and technique. It is hoped that an improvement of cervical arthroplasty occurs in terms of materials and design as spinal surgeons enter a new dines of the management of cervical spine disease.

  19. Application of a vibrating device for the prevention of flexion contracture after total knee arthroplasty.

    Manó, Sándor; Pálinkás, Judit; Szabó, János; Nagy, Judit T; Bakó, Katalin; Csernátony, Zoltán


    Our research team developed a new, heel support-based static and vibrating complementary treatment method for the prevention of flexion contractures often arising after total knee arthroplasty. We examined the efficiency of the method performing a randomized clinical trial with 144 patients undergoing total knee replacement. Seventy-nine patients were treated for 1 week with a generally used continuous passive motion (CPM) device complemented with our new method, which was based on the application of a static and an alternating heel support. The 65 patients in the control group were treated with only a CPM device as in usual clinical practice. The femoro-tibial angle was measured immediately following surgery, and after 1 week of treatment. At the end of the 1 week treatment, the target extension angle (0° ± 5°) was achieved by significantly more patients with the new combined method. This way the elevated heel rest and the vibrating device proved to be a good adjunct treatment along with the CPM used in routine clinical practice in the first place for the prevention of flexion contractures.

  20. [Experience with prosthetic disc nucleus device in Mexico. Final report of a 4-year follow-up].

    Rosales-Olivares, Luis Miguel; Pérez-Víquez, Ariel; Miramontes-Martínez, Víctor; Alpízar-Aguirre, Armando; Reyes-Sánchez, Alejandro Antonio


    Discal hernia is generally treated by discectomies that are mutilating and cause instability and low back pain in 50% of the patients. Partial arthroplasty is used in an attempt to avoid degeneration after a discectomy. Nineteen patients from the INR (National Institute of Rehabilitation) were selected with extruded discal hernia. All inclusion criteria were met, with a minimal follow-up of 4 years. Evolution was evaluated with the Oswestry scale (OS) and x-ray studies. Statistical analysis was done with Student's t-test. Sixteen men and three women were included in the study, with an average age of 35.4 years. OS before surgery was 57.37% and improved to 22% (p < 0.001). The results obtained in the Prolo scale 4 years later were for the economy scale, p < 0.001 (Wilcoxon Z = 3.87) and for the functional scale, p < 0.001 (Wilcoxon Z = -3.94). The intervertebral space height (IS) before surgery was 6 and 8 mm, and 4 years later, in 12 patients it remained between 8 and 10 mm. The prosthesis had variations according to its initial placement in seven patients, and in all there was subsidence. In two cases migration surpassed the limits of the vertebral body without clinical repercussion. None of the patients required re-operation. Prosthetic disc nucleus device improved clinical conditions and x-rays of the patients using Oswestry, Prolo and intersomatic space height enhancement after 4 years of follow-up in 12/19 patients.

  1. Comparison of 2 Zero-Profile Implants in the Treatment of Single-Level Cervical Spondylotic Myelopathy: A Preliminary Clinical Study of Cervical Disc Arthroplasty versus Fusion.

    Sheng Shi

    Full Text Available Cervical disc arthroplasty (CDA with Discover prosthesis or anterior cervical discectomy and fusion (ACDF with Zero-P cage has been widely used in the treatment of cervical spondylotic myelopathy (CSM. However, little is known about the comparison of the 2 zero-profile implants in the treatment of single-level CSM. The aim was to compare the clinical outcomes and radiographic parameters of CDA with Discover prosthesis and ACDF with Zero-P cage for the treatment of single-level CSM.A total of 128 consecutive patients who underwent 1-level CDA with Discover prosthesis or ACDF with Zero-P cage for single-level CSM between September 2009 and December 2012 were included in this study. Clinical outcomes were evaluated using the Japanese Orthopaedic Association (JOA score and Neck Disability Index (NDI. For radiographic assessment, the overall sagittal alignment (OSA, functional spinal unit (FSU angle, and range of motion (ROM at the index and adjacent levels were measured before and after surgery. Additionally, the complications were also recorded.Both treatments significantly improved all clinical parameters (P 0.05. Besides, no significant differences existed in dysphagia, subsidence, or adjacent disc degeneration between the 2 groups (P > 0.05. However, significant differences occurred in prosthesis migration in CDA group.The results of this study showed that clinical outcomes and radiographic parameters were satisfactory and comparable with the 2 techniques. However, more attention to prosthesis migration of artificial cervical disc should be paid in the postoperative early-term follow-up.

  2. The NEtherlands Cervical Kinematics (NECK Trial. Cost-effectiveness of anterior cervical discectomy with or without interbody fusion and arthroplasty in the treatment of cervical disc herniation; a double-blind randomised multicenter study

    van den Akker Elske


    Full Text Available Abstract Background Patients with cervical radicular syndrome due to disc herniation refractory to conservative treatment are offered surgical treatment. Anterior cervical discectomy is the standard procedure, often in combination with interbody fusion. Accelerated adjacent disc degeneration is a known entity on the long term. Recently, cervical disc prostheses are developed to maintain motion and possibly reduce the incidence of adjacent disc degeneration. A comparative cost-effectiveness study focused on adjacent segment degeneration and functional outcome has not been performed yet. We present the design of the NECK trial, a randomised study on cost-effectiveness of anterior cervical discectomy with or without interbody fusion and arthroplasty in patients with cervical disc herniation. Methods/Design Patients (age 18-65 years presenting with radicular signs due to single level cervical disc herniation lasting more than 8 weeks are included. Patients will be randomised into 3 groups: anterior discectomy only, anterior discectomy with interbody fusion, and anterior discectomy with disc prosthesis. The primary outcome measure is symptomatic adjacent disc degeneration at 2 and 5 years after surgery. Other outcome parameters will be the Neck Disability Index, perceived recovery, arm and neck pain, complications, re-operations, quality of life, job satisfaction, anxiety and depression assessment, medical consumption, absenteeism, and costs. The study is a randomised prospective multicenter trial, in which 3 surgical techniques are compared in a parallel group design. Patients and research nurses will be kept blinded of the allocated treatment for 2 years. The follow-up period is 5 years. Discussion Currently, anterior cervical discectomy with fusion is the golden standard in the surgical treatment of cervical disc herniation. Whether additional interbody fusion or disc prothesis is necessary and cost-effective will be determined by this trial

  3. Adjacent-level arthroplasty following cervical fusion.

    Rajakumar, Deshpande V; Hari, Akshay; Krishna, Murali; Konar, Subhas; Sharma, Ankit


    OBJECTIVE Adjacent-level disc degeneration following cervical fusion has been well reported. This condition poses a major treatment dilemma when it becomes symptomatic. The potential application of cervical arthroplasty to preserve motion in the affected segment is not well documented, with few studies in the literature. The authors present their initial experience of analyzing clinical and radiological results in such patients who were treated with arthroplasty for new or persistent arm and/or neck symptoms related to neural compression due to adjacent-segment disease after anterior cervical discectomy and fusion (ACDF). METHODS During a 5-year period, 11 patients who had undergone ACDF anterior cervical discectomy and fusion (ACDF) and subsequently developed recurrent neck or arm pain related to adjacent-level cervical disc disease were treated with cervical arthroplasty at the authors' institution. A total of 15 devices were implanted (range of treated levels per patient: 1-3). Clinical evaluation was performed both before and after surgery, using a visual analog scale (VAS) for pain and the Neck Disability Index (NDI). Radiological outcomes were analyzed using pre- and postoperative flexion/extension lateral radiographs measuring Cobb angle (overall C2-7 sagittal alignment), functional spinal unit (FSU) angle, and range of motion (ROM). RESULTS There were no major perioperative complications or device-related failures. Statistically significant results, obtained in all cases, were reflected by an improvement in VAS scores for neck/arm pain and NDI scores for neck pain. Radiologically, statistically significant increases in the overall lordosis (as measured by Cobb angle) and ROM at the treated disc level were observed. Three patients were lost to follow-up within the first year after arthroplasty. In the remaining 8 cases, the duration of follow-up ranged from 1 to 3 years. None of these 8 patients required surgery for the same vertebral level during the follow

  4. Comparability of modern recording devices for speech analysis: smartphone, landline, laptop, and hard disc recorder.

    Vogel, Adam P; Rosen, Kristin M; Morgan, Angela T; Reilly, Sheena


    Large-scale multi-site experimental and clinical speech protocols require high-fidelity, easy-to-use speech recording technologies. However, little is known about the reliability and comparability of affordable, portable and commonly used technologies with traditional well-validated devices (e.g., a hard disc recorder with a high-quality microphone). To examine the comparability of speech and voice samples acquired from protocols involving high- and low-quality devices. Speech samples were acquired simultaneously from 15 healthy adults using four devices and analyzed acoustically for measures of timing and voice quality. For the purpose of making initial comparisons, methods were deemed comparable if the resultant acoustic data yielded root mean squared error values ≤10% and statistically significant Spearman's correlation coefficients. The data suggest that there is significant and widespread variability in the quality and reliability between different acquisition methods for voice and speech recording. Not one method provided statistically similar data to the protocol using the benchmark device (i.e., a high-quality recorder coupled with a condenser microphone). Acoustic analysis cannot be assumed to be comparable if different recording methods are used to record speech. Findings have implications for researchers and clinicians hoping to make comparisons between labs or, where lower-quality devices are suggested, to offer equal fidelity. © 2015 S. Karger AG, Basel.

  5. Lumbar disc arthroplasty: indications, biomechanics, types, and radiological criteria; Lumbale Bandscheibenendoprothesen: Indikationen, Biomechanik, Typen und radiologische Kriterien

    Baur-Melnyk, A.; Reiser, M.F. [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet, Orthopaedische Klinik und Poliklinik, Muenchen (Germany); Birkenmaier, C. [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet, Institut fuer Klinische Radiologie, Muenchen (Germany)


    Lumbar total disc replacement (TDR) was developed to treat a painful degenerative lumbar motion segment while avoiding the disadvantages of fusion surgery, such as adjacent segment instabilities. Early clinical results with TDR have shown a significant reduction in low back pain and a significant improvement in disability scores. When compared to fusion, the results with TDR tend to be superior in the short-term follow-up and initial rehabilitation is faster. The radiological assessment is an integral part of the preoperative work-up. Plain X-rays of the lumbar spine should be complemented by flexion - extension views in order to assess residual segmental mobility. Computed tomography is used to exclude osteoarthritis of the zygapophyseal joints, Baastrup's disease (kissing spines) and other sources of low back pain. Magnetic resonance imaging is useful to exclude substantial disc protrusions; it allows for the detection of disc dehydration and bone marrow edema in the case of activated spondylochondrosis. If osteoporosis is suspected, an osteodensitometry of the lumbar spine should be performed. Postoperative plain X-rays should include antero-posterior and lateral views as well as flexion - extension views in the later postoperative course. Measurements should determine the disc space height in the lateral view, the segmental and total lumbar lordosis as well as the segmental mobility in the flexion - extension views. The ideal position of a TDR is exactly central in the ap-view and close to the dorsal border of the vertebral endplates in the lateral view. Malpositioning may cause segmental hyperlordosis and unbalanced loading of the endplates with the risk of implant subsidence and migration. (orig.) [German] Die lumbale Bandscheibenendoprothese (LBEP) wurde entwickelt, um ein schmerzhaftes lumbales Bewegungssegment unter Vermeidung der Nachteile einer Fusionsoperation zu behandeln. Erste klinische Ergebnisse der LBEP zeigen eine signifikante Reduktion der

  6. Placing a price on medical device innovation: the example of total knee arthroplasty.

    Lisa G Suter

    Full Text Available BACKGROUND: Total knee arthroplasty (TKA is common, effective, and cost-effective. Innovative implants promising reduced long-term failure at increased cost are under continual development. We sought to define the implant cost and performance thresholds under which innovative TKA implants are cost-effective. METHODS: We performed a cost-effectiveness analysis using a validated, published computer simulation model of knee osteoarthritis. Model inputs were derived using published literature, Medicare claims, and National Health and Nutrition Examination Survey data. We compared projected TKA implant survival, quality-adjusted life expectancy (QALE, lifetime costs, and cost-effectiveness (incremental cost-effectiveness ratios or ICERs of standard versus innovative TKA implants. We assumed innovative implants offered 5-70% decreased long-term TKA failure rates at costs 20-400% increased above standard implants. We examined the impact of patient age, comorbidity, and potential increases in short-term failure on innovative implant cost-effectiveness. RESULTS: Implants offering ≥50% decrease in long-term TKA failure at ≤50% increased cost offered ICERs <$100,000 regardless of age or baseline comorbidity. An implant offering a 20% decrease in long-term failure at 50% increased cost provided ICERs <$150,000 per QALY gained only among healthy 50-59-year-olds. Increasing short-term failure, consistent with recent device failures, reduced cost-effectiveness across all groups. Increasing the baseline likelihood of long-term TKA failure among younger, healthier and more active individuals further enhanced innovative implant cost-effectiveness among younger patients. CONCLUSIONS: Innovative implants must decrease actual TKA failure, not just radiographic wear, by 50-55% or more over standard implants to be broadly cost-effective. Comorbidity and remaining life span significantly affect innovative implant cost-effectiveness and should be considered in the

  7. Tulip malformation of the left atrial disc in the Lifetech Cera ASD device: a novel complication of percutaneous ASD closure.

    Hayes, Nicholas; Rosenthal, Eric


    A previously unreported tulip-like malformation of the left atrial disc was encountered during percutaneous closure of an atrial septal defect (ASD) using the LifeTech Cera ASD device, requiring snare assistance to permit recapture into the delivery sheath. This was likely to be as a result of attempting to recapture the left atrial disc whilst it remained in contact with some part of the atrial septum or left atrial wall. To help avoid this, it is recommended to ensure complete intracavity positioning of the Cera device prior to retrieval into the sheath. Copyright © 2011 Wiley Periodicals, Inc.

  8. Biomechanics of a posture-controlling cervical artificial disc: mechanical, in vitro, and finite-element analysis.

    Crawford, Neil R; Arnett, Jeffery D; Butters, Joshua A; Ferrara, Lisa A; Kulkarni, Nikhil; Goel, Vijay K; Duggal, Neil


    Different methods have been described by numerous investigators for experimentally assessing the kinematics of cervical artificial discs. However, in addition to understanding how artificial discs affect range of motion, it is also clinically relevant to understand how artificial discs affect segmental posture. The purpose of this paper is to describe novel considerations and methods for experimentally assessing cervical spine postural control in the laboratory. These methods, which include mechanical testing, cadaveric testing, and computer modeling studies, are applied in comparing postural biomechanics of a novel postural control arthroplasty (PCA) device versus standard ball-and-socket (BS) and ball-in-trough (BT) arthroplasty devices. The overall body of evidence from this group of tests supports the conclusion that the PCA device does control posture to a particular lordotic position, whereas BS and BT devices move freely through their ranges of motion.

  9. Revision total hip and knee arthroplasty implant identification: implications for use of Unique Device Identification 2012 AAHKS member survey results.

    Wilson, Natalia A; Jehn, Megan; York, Sally; Davis, Charles M


    FDA's Unique Device Identification (UDI) Rule will mandate manufacturers to assign unique identifiers to their marketed devices. UDI use is expected to improve implant documentation and identification. A 2012 American Association of Hip and Knee Surgeons membership survey explored revision total hip and knee arthroplasty implant identification processes. 87% of surgeons reported regularly using at least 3 methods to identify failed implants pre-operatively. Median surgeon identification time was 20 min; median staff time was 30 min. 10% of implants could not be identified pre-operatively. 2% could not be identified intra-operatively. UDI in TJA registry and UDI in EMR were indicated practices to best support implant identification and save time. FDA's UDI rule sets the foundation for UDI use in patient care settings as standard practice for implant documentation. © 2013.

  10. Rapid Detection of Salmonella enterica in Food Using a Compact Disc-Shaped Device

    Shunsuke Furutani


    Full Text Available Rapid detection of food-borne pathogens is essential to public health and the food industry. Although the conventional culture method is highly sensitive, it takes at least a few days to detect food-borne pathogens. Even though polymerase chain reaction (PCR can detect food-borne pathogens in a few hours, it is more expensive and unsatisfactorily sensitive relative to the culture method. We have developed a method to rapidly detect Salmonella enterica by using a compact disc (CD-shaped device that can reduce reagent consumption in conventional PCR. The detection method, which combines culture and PCR, is more rapid than the conventional culture method and is more sensitive and cheaper than PCR. In this study, we also examined a sample preparation method that involved collecting bacterial cells from food. The bacteria collected from chicken meat spiked with S. enterica were mixed with PCR reagents, and PCR was performed on the device. At a low concentration of S. enterica, the collected S. enterica was cultured before PCR for sensitive detection. After cultivation for 4 h, S. enterica at 1.7 × 104 colony-forming units (CFUs·g−1 was detected within 8 h, which included the time needed for sample preparation and detection. Furthermore, the detection of 30 CFUs·g−1 of S. enterica was possible within 12 h including 8 h for cultivation.

  11. 颈椎人工椎间盘置换后对相邻节段退变的影响%Effect of cervical disc arthroplasty on adjacent segment degeneration

    孙宇; 赵衍斌; 周非非; 张凤山; 潘胜发; 周方; 刘忠军


    Objective:To investigate the adjacent segment degeneration after single level cervical disc arthroplasty. Method : Patients received single level cervical arthroplasty in our institute were reviewed retrospectively. Up to October 2010,a total of 80 patients gained at least 20 months' follow-up.There were 8 cases of C3/4,15 C4/5,49 C5/6 and 8 C6/7.41 patents received Bryan Disc cervical prosthesis and 39 received ProDisc-C prosthesis. Adjacent segment degeneration was evaluated on X-ray and magnetic resonance imaging (MRI) at preoperative and final follow-up.X-ray based adjacent segment degeneration included the presence of aoy of the following parameters:narrowing of disc space>10%,new anterior or/and extended osteophyte formation,calcification of anterior longitudinal ligament. Cervical disc degeneration was evaluated according to Miyazaki's grading system based on T2-weighted MRI.Result:The mean follow-up period was 38 months (range,20-64 months).Of 160 segments at final follow-up,8 distal adjacent segments were excluded due to unavailability of X-ray,adjacent segment degeneration was observed in 21 of 152 segments(13.8%) based on X-ray findings.The rate of adjacent segment degeneration for Bryan disc group was 10.0%,which was lower than that of ProDisc-C group (18.1%).47 patients gained MRI follow-up,and adjacent segment degeneration was observed in 14 of 94 segments (14.9%).The rate of MRI-based adjacent segment degeneration for Bryan Disc group was 12.5%,which was also lower than that of ProDisc-C group (22.7%).No adjacent segment disease developed at final follow-up. Conclusion:Less than 15% cases develop adjacent segment degeneration 38 months after cervical disc arthroplasty,and the effect may vary between different prosthesis.%目的:观察单节段颈椎人工椎间盘置换术后相邻节段退变情况.方法:截止到2010年10月在我院行单节段颈椎人工椎间盘置换术后随访20个月以上且资料完整、既

  12. Rabbit model of intervertebral disc degeneration by external compression device characterized by X-ray, MRI, histology, and cell viability

    Ismail Ismail


    Full Text Available Appropriate experimental animal models, which mimic the degenerative process occurring in human intervertebral disc (IVD breakdown and can be used for new treatment studies such as tissue engineering or disc distraction are lacking. We studied the external compression device that used by Kroeber et al to create intervertebral disc degeneration in rabbit model characterized by X-ray, MRI, Histology, and Cell Viability. Ten NZW rabbit were randomly assigned to one of five groups. Intervertebral disc VL4-L5 are compressed using an external loading device, 1.9 MPa. First group rabbit are loaded for 14 days, second loaded for 28 days, thirth group are loaded for 14 days, and unloaded for 14 days, fourth group loaded for 28 days and unloaded for 28 days. The fifth group, rabbits underwent a sham operation. Additional, rabbits were used as sample for cell viability study. In disc height : sample in group one have biggest decreasing of disc height, that is 23.9 unit. In MRI assessment, the worst grade is grade 3. In histological score, the worst group is group three (58.69, and the best is group 4 (45.69. Group one have the largest dead cell, that are 403.5, and the smallest is group four (124.75. Trypan blue staining showed that group four have better viable cell (91.1 compare than group three (86.4. The study conclude disc degeneration can be created by external axial loading for 14 days in rabbit intervertebral disc. Duration of 28 days unloading gave better result for cells to recover. (Med J Indones 2006; 15:199-207  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Keywords: Rabbit model –intervertebral disc degeneration- external compression device-X-ray, MRI, Histology, and Cell viabilty /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso

  13. Implant survival of the most common cemented total hip devices from the Nordic Arthroplasty Register Association database

    Junnila, Mika; Laaksonen, Inari; Eskelinen, Antti


    Background and purpose - According to previous Nordic Arthroplasty Register Association (NARA) data, the 10-year implant survival of cemented total hip arthroplasties (THAs) is 94% in patients aged 65-74 and 96% in patients aged 75 or more. Here we report a brand-level comparison of cemented THA...

  14. Position controlled Knee Rehabilitation Orthotic Device for Patients after Total Knee Replacement Arthroplasty

    Wannaphan, Patsiri; Chanthasopeephan, Teeranoot


    Knee rehabilitation after total knee replacement arthroplasty is essential for patients during their post-surgery recovery period. This study is about designing one degree of freedom knee rehabilitation equipment to assist patients for their post-surgery exercise. The equipment is designed to be used in sitting position with flexion/extension of knee in sagittal plane. The range of knee joint motion is starting from 0 to 90 degrees angle for knee rehabilitation motion. The feature includes adjustable link for different human proportions and the torque feedback control at knee joint during rehabilitation and the control of flexion/extension speed. The motion of the rehabilitation equipment was set to move at low speed (18 degrees/sec) for knee rehabilitation. The rehabilitation link without additional load took one second to move from vertical hanging up to 90° while the corresponding torque increased from 0 Nm to 2 Nm at 90°. When extra load is added, the link took 1.5 seconds to move to 90° The torque is then increased from 0 Nm to 4 Nm. After a period of time, the speed of the motion can be varied. User can adjust the motion to 40 degrees/sec during recovery activity of the knee and users can increase the level of exercise or motion up to 60 degrees/sec to strengthen the muscles during throughout their rehabilitation program depends on each patient. Torque control is included to prevent injury. Patients can use the equipment for home exercise to help reduce the number of hospital visit while the patients can receive an appropriate therapy for their knee recovery program.

  15. Instrumented posterior lumbar interbody fusion (PLIF) with interbody fusion device (Cage) in degenerative disc disease (DDD): 3 years outcome.

    Ahsan, M K; Hossain, M A; Sakeb, N; Khan, S I; Zaman, N


    This prospective interventional study carried out at Bangabandhu Sheikh Mujib Medical University and a private hospital in Dhaka, Bangladesh during the period from October 2003 to September 2011. Surgical treatment of degenerative disc disease (DDD) should aim to re-expand the interbody space and stabilize until fusion is complete. The present study conducted to find out the efficacy of using interbody fusion device (Cage) to achieve interbody space re-expansion and fusion in surgical management of DDD. We have performed the interventional study on 53 patients, 42 female and 11 male, with age between 40 to 67 years. All the patients were followed up for 36 to 60 months (average 48 months). Forty seven patients were with spondylolisthesis and 06 with desiccated disc. All subjects were evaluated with regard to immediate and long term complications, radiological fusion and interbody space re-expansion and maintenance. The clinical outcome (pain and disability) was scored by standard pre and postoperative questionnaires. Intrusion, extrusion and migration of the interbody fusion cage were also assessed. Forty seven patients were considered to have satisfactory outcome in at least 36 months follow up. Pseudoarthrosis developed in 04 cases and 06 patients developed complications. In this series posterior lumbar interbody fusion (PLIF) with interbody cage and instrumentation in DDD showed significant fusion rate and maintenance of interbody space. Satisfactory outcome observed in 88.68% cases.

  16. Implant survival of the most common cemented total hip devices from the Nordic Arthroplasty Register Association database

    Junnila, Mika; Laaksonen, Inari; Eskelinen, Antti


    Background and purpose - According to previous Nordic Arthroplasty Register Association (NARA) data, the 10-year implant survival of cemented total hip arthroplasties (THAs) is 94% in patients aged 65-74 and 96% in patients aged 75 or more. Here we report a brand-level comparison of cemented THA...... based on the NARA database, which has not been done previously. Patients and methods - We determined the rate of implant survival of the 9 most common cemented THAs in the NARA database. We used Kaplan-Meier analysis with 95% CI to study implant survival at 10 and 15 years, and Cox multiple regression...

  17. Current research status of the prosthesis-related complication after cervical disc arthroplasty%颈椎间盘置换术后假体相关并发症的研究现状

    赵郭盛; 张圆; 权正学


    近年来,为避免颈椎融合术治疗颈椎退行性疾病所带来的假关节形成及邻近节段退变加速等问题,颈椎间盘置换术作为一种非融合技术广泛应用于临床,其疗效确切,已逐渐成为治疗颈椎退行性疾病的常规手术方式。但随着该技术应用的深入,随访年限的增加,颈椎间盘置换术后与假体相关的一系列特殊并发症逐渐被学者报道。本文就颈椎间盘置换术后假体相关并发症的研究现状作一综述。%Recently,to avoid the adverse effect such as pseudoarthrosis and accelerated degeneration of ad-jacent segments resulting from cervical fusion, cervical disc arthroplasty ( CDA) has been widely used in clinical practice as a procedure in the treatment of cervical degeneration disease.With satisfactory outcomes,CDA has been gradually accepted as a conventional procedure in treating cervical spondylosis.However,with the increased number of the total operations and the accumulation of follow-up information,some complications due to the prosthesis were revealed.Thus,we collect the related references and conduct this study to review the current status of prosthesis-re-lated complications after cervical disc arthoplasty.

  18. 单节段人工椎间盘置换治疗颈椎病的中长期疗效%Medium and long term result of the single level cervical disc arthroplasty for cervical spondylosis meylopathy

    张雪松; 王岩; 张永刚; 肖嵩华; 王征; 陆宁; 毛克亚; 崔庚; 徐辉; 齐登彬


    目的:评价单节段颈椎人工椎间盘置换(cervical disc arthroplasty,CDA)对颈椎病的中长期治疗效果.方法:2003年12月~2005年12月采用前瞻、随机、对照研究单节段Bryan假体CDA与传统前路颈椎减压融合(ACDF)手术治疗颈椎病的疗效,所有患者均按统一的纳入、排除标准进入临床研究,共80例,随机分为两组,并进行均衡性检验,一组进行CDA手术,另一组进行ACDF手术,术后经1d、3个月、6个月、1年、2年、5年及2012年6月的末次随访.其中CDA组32例、ACDF组35例完成了随访,应用动力位X线片观察置换间隙活动度,采用McAfee异位骨化分级方法评定颈椎间盘置换术后异位骨化情况,在MRI T2加权像上采用Miyazaki颈椎间盘退变分级方法评定两组相邻节段椎间盘退变情况,采用颈椎活动障碍指数(NDI)和疼痛视觉模拟评分(VAS)评价术后症状改善程度.结果:本组病例随访7.2~9.6年,平均8.8年.CDA组假体位置良好,无塌陷或移位发生,末次随访时矢状面假体置换间隙活动度1.20°~8.20°,平均6.35°±1.45°;32例患者中8例(25%)置换间隙发生异位骨化,其中2例(6.25%)置换节段丧失活动度;翻修3例,1例因头侧邻近间隙退变、颈椎间盘突出压迫脊髓;2例因头侧跳跃间隙后方骨赘压迫脊髓;末次随访时置换间隙相邻的其他63个节段中22个椎间盘退变分级加重1级,8个加重2级,但无相关临床症状出现.ACDF组融合率100%,翻修3例,2例因头侧邻近间隙退变、存在神经症状;1例因尾侧邻近间隙退变,压迫脊髓;其余67个相邻节段中34个椎间盘退变分级加重1级,15个加重2级,但均无相关临床症状出现.末次随访时CDA组的NDI、颈部VAS及上肢VAS评分分别为16.83±3.12、1.17±0.41及1.96±0.51分,ACDF组分别为17.21±3.53、1.23±0.35及1.86±0.62分,较术前均显著改善,但两组间比较无显著性差异(P>0.05).结论:颈椎人工椎间盘置换术

  19. Artificial cervical disc replacement: Principles, types and techniques

    Sekhon L


    Full Text Available Cervical arthroplasty after anterior decompression with insertion of a prosthetic total disc replacement has been suggested as an alternate to anterior cervical fusion. Currently there are four cervical arthroplasty devices available on the market whose results in clinical use have been reported. Each device varies in terms of materials, range of motion, insertion technique and constraint. It is not known which device is ideal. Early studies suggest that in the short term, the complication rate and efficacy is no worse than fusion surgery. Long-term results have not yet been reported. This review examines the current prostheses available on the market as well as discussing issues regarding indications and technique. Pitfalls are discussed and early experiences reviewed. In time, it is hoped that a refinement of cervical arthroplasty occurs in terms of both materials and design as well as in terms of indications and clinical outcomes as spinal surgeons enter a new era of the management of cervical spine disease.

  20. Venous Hemodynamics After Total Hip Arthroplasty: A Comparison Between Portable vs Stationary Pneumatic Compression Devices and the Effect of Body Position.

    Berliner, Jonathan L; Ortiz, Philippe A; Lee, Yuo-Yu; Miller, Theodore T; Westrich, Geoffrey H


    Improvements in device design have allowed for portable pneumatic compression devices (PPCDs). However, portability results in smaller pumps that move less blood. Additionally, although patients often stand when wearing PPCDs, few studies have evaluated the hemodynamic effects of PCDs while standing. A crossover study was performed to compare a PPCD (ActiveCare+S.F.T.; Medical Compression Systems, Or Akiva, Israel) to a stationary pneumatic compression device (SPCD) (VenaFlow; DJO Global, Carlsbad, CA) on hemodynamics in supine and standing positions among 2 cohorts composed of 10 controls and 10 total hip arthroplasty patients. Differences in baseline peak venous velocity (PVV), PVV with each PCD, and delta PVV with each PCD were assessed. A multivariate analysis was performed to examine differences between cohorts, devices, and position. In both positions, the SPCD demonstrated a larger change in PVV when compared to the PPCD (P < .001). The total hip arthroplasty group had a greater delta PVV while standing when considering both PCDs together (P < .001). When considering both cohorts, delta PVV was greater while standing, only when the SPCD was used (P < .001). There was no difference between standing and supine positions when the PPCD was used. The SPCD demonstrated a greater capacity to increase PPV in the supine and standing positions. The SPCD generated greater values of PVV and delta PVV in the standing position. Although these results demonstrate a difference between devices, it is important to establish the PVV necessary to prevent VTE before one is considered more effective. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Does core mobility of lumbar total disc arthroplasty influence sagittal and frontal intervertebral displacement? Radiologic comparison with fixed-core prosthesis

    Delécrin, Joël; Allain, Jérôme; Beaurain, Jacques; Steib, Jean-Paul; Chataigner, Hervé; Aubourg, Lucie; Huppert, Jean; Ameil, Marc; Nguyen, Jean-Michel


    Background An artificial disc prosthesis is thought to restore segmental motion in the lumbar spine. However, it is reported that disc prosthesis can increase the intervertebral translation (VT). The concept of the mobile-core prosthesis is to mimic the kinematic effects of the migration of the natural nucleus and therefore core mobility should minimize the VT. This study explored the hypothesis that core translation should influence VT and that a mobile core prosthesis may facilitate physiological motion. Methods Vertebral translation (measured with a new method presented here), core translation, range of motion (ROM), and distribution of flexion-extension were measured on flexion-extension, neutral standing, and lateral bending films in 89 patients (63 mobile-core [M]; 33 fixed-core [F]). Results At L4-5 levels the VT with M was lower than with F and similar to the VT of untreated levels. At L5-S1 levels the VT with M was lower than with F but was significantly different compared to untreated levels. At M levels a strong correlation was found between VT and core translation; the VT decreases as the core translation increases. At F levels the VT increases as the ROM increases. No significant difference was found between the ROM of untreated levels and levels implanted with either M or F. Regarding the mobility distribution with M and F we observed a deficit in extension at L5-S1 levels and a similar distribution at L4-5 levels compared to untreated levels. Conclusion The intervertebral mobility was different between M and F. The M at L4-5 levels succeeded to replicate mobility similar to L4-5 untreated levels. The M at L5-S1 succeeded in ROM, but failed regarding VT and mobility distribution. Nevertheless M minimized VT at L5-S1 levels. The F increased VT at both L4-5 and L5-S1. Clinical Relevance This study validates the concept that the core translation of an artificial lumbar disc prosthesis minimizes the VT. PMID:25802632

  2. A Meta-analysis of Cervical Disc Arthroplasty Compared to Anterior Cervical Discectomy and Fu-sion for Degenerative Cervical Disc Disease%颈椎间盘置换与融合治疗退变性颈椎间盘疾病的 Meta 分析

    石青鹏; 朱永林


    Objective To systematically compare the outcomes of cervical disc arthroplasty with anterior cervical discecto-my and fusion in the treatment of single-level degenerative cervical disc disease. Methods The references concerning cervical disc arthroplasty and anterior cervical discectomy and fusion for the singel-level degenerative cervical disc disease were re-trieved through PubMed,Cochrane Library,Ovid,SpringerLink,the China Biological Medicine Database,Wafang Database and Weipu Database,as well as by manually searching the related journals and literature. The eligible trials were extracted accord-ing to the inclusion and exclusion criteria. The methodological quality of the included trials were evaluated. RevMan5. 1 soft-ware was used for data analysis. Results Eight randomized controlled trials were included in the final Meta-analysis. The re-sults of Meta-analysis showed that statistically difference between these procedures in the SF-36(MD = 0. 98,95% CI:- 0. 33~ - 2. 29,Z = 1. 46,P = 0. 14),complications(OR = 0. 60,95% CI:0. 34 ~ 1. 04,P = 0. 07),reoperation rate(OR = 0. 52, 95% CI:0. 26 ~ 1. 05,Z = 1. 83,P = 0. 07). There were no statistically difference in the neck disability index(MD = - 2. 74, 95% CI:- 4. 57 ~ - 0. 91,Z = 2. 93,P = 0. 003),neck VAS(MD = - 2. 84,95% CI:- 4. 85 ~ - 0. 84,Z = 2. 78,P = 0. 005) and arm pain VAS(MD = - 1. 84,95% CI:- 3. 07 ~ - 0. 61,Z = 2. 92,P = 0. 003). Conclusion In treatment of single-level degenerative cervical disc disease,cervical disc arthroplasty has better outcomes in the improvement of pain symptom and neck function,but no superiority in complications,reoperation rate and SF-36 scores.%目的:系统性评价颈椎间盘置换与颈椎间盘摘除和融合治疗单节段退变性颈椎间盘疾病的效果。方法计算机检索 PubMed、Cochrane Library、Ovid、SpringerLink、中国生物医学文献数据库、万方、维普等数据库,手工检索相关杂志及纳入研究的参考文献,制

  3. 单节段半限制型Activ-C人工椎间盘置换术的早期疗效观察%Observation of early results after single-level semi-constrained Activ-C cervical disc arthroplasty

    李洪珂; 张长江; 王明君; 杨贤玉; 李来好


    目的:观察半限制型Activ-C人工椎间盘置换术治疗单节段颈椎病的早期临床疗效。方法2009年7月至2012年9月,在我院接受Activ-C人工椎间盘置换术并获得随访的单节段颈椎病患者共28例,男18例,女10例,年龄32~62岁,平均45.2岁。采用日本骨科协会(Japaneseorthopedicassociation,JOA)评分、颈椎活动障碍指数(neckdisabilityindex,NDI)和疼痛视觉模拟评分(visualanaloguescale,VAS)评价术后症状改善程度,比较手术前后的颈椎曲度、手术节段活动度变化,观察统计手术并发症情况。结果随访时间12~36个月,平均17.8个月,JOA脊髓功能评分从(8.5±2.5)分增加至(14.8±1.5)分,NDI评分从(24.8±6.9)分下降至(7.3±4.8)分,颈部VAS评分从(6.8±1.3)分下降至(1.2±0.4)分,上肢VAS评分从(7.4±1.2)分下降至(1.1±0.4)分,均有明显改善(P<0.05)。置换节段活动度从术前平均(9.6±4.3)°增加至末次随访时平均(10.8±3.5)°,差异无统计学意义(P>0.05);颈椎整体曲度术前为(12.9±10.5)°,末次随访时为(15.4±9.1)°,但差异无统计学意义(P>0.05)。结论单节段半限制型Activ-C人工椎间盘置换术可有效改善颈椎病患者的临床症状,维持颈椎的生理曲度和活动度,早期临床疗效满意。%Objective To evaluate the early clinical results of semi-constrained Activ-C cervical disc arthroplasty for single-level cervical spondylosis. Methods From July 2009 to September 2012, 28 patients with single-level cervical spondylosis underwent Activ-C cervical disc arthroplasty and were followed up. There were 18 males and 10 females, whose mean age was 45.2 years old ( range: 32-62 years ). The Japanese Orthopedic Association ( JOA ) scores, Neck Disability Index ( NDI ) and Visual Analogue Scale ( VAS ) were used to evaluate the postoperative improvement of symptoms, compare the preoperative and postoperative cervical curvature and segmental

  4. Distraction Arthroplasty

    ... arthroplasty? The major goal of this treatment is healing of damaged tissue that occurs from arthritis. Unloading the ankle, along with the use of range of motion activity, is believed to help restore some of the ...

  5. Intermittent pneumatic compression devices combined with anticoagulants for prevention of symptomatic deep vein thrombosis after total knee arthroplasty: a pilot study

    Liu, Pengcheng; Liu, Junfeng; Chen, Liyang; Xia, Kuo; Wu, Xing


    Objectives To investigate the effectiveness of intermittent pneumatic compression (IPC) devices combined with anticoagulants for the prevention of deep vein thrombosis (DVT) after total knee arthroplasty (TKA). Patients and methods In total 120 patients were involved in this pilot study. Patients in the control group received 10 mg of rivaroxaban per day after surgery. In addition to the prescription of rivaroxaban, IPC devices were used in the experimental group. The diagnosis of DVT was made by compression duplex ultrasound on postoperative day 9. Results The incidence rates of overall, proximal, distal, and intermuscular DVT were 8.3%, 0%, 1.67%, and 6.67% in the experimental group; and 18.3%, 0%, 5%, and 13.33% in the control group, respectively. The incidence rates of total, distal, and intermuscular DVT in TKA patients was significantly lower in the experimental group than in the control group. For patients with DVT, enoxaparin was used instead of rivaroxaban, and DVT was found to have disappeared 10–14 days postoperatively. Conclusion Compared with the use of rivaroxaban alone, IPC devices combined with anticoagulants can significantly reduce the incidence rate of distal DVT and intermuscular DVT in the early postoperative period after TKA. PMID:28243107


    Krasin P. S.


    Full Text Available In the materials of the article we mention the regularities of changes in the volume and surface solid temperature gradients and self-ventilated brake discs and illustrate their impact on the main operating parameters of the friction pairs of disk-to-pad brakes of the A 172 bus; the relationship between thermo-physical parameters of polished and matte surfaces with areas of brake discs of various types. The influence of the type of tests on the pairs of loaded with energy friction disk and pad brakes of the vehicle. We have set the intensity of heat exchange processes from the surfaces of the brake discs of various types. It is shown that this leads to increased surface temperature gradient. The volume and the surface temperature gradients of the brake discs were determined with the involvement of the hypothesis of summation of temperatures on the surface when you post the generated electric currents. It was found that in the surface layer of the working surface of a solid brake disc at its pulse heating under the influence of the temperature of the flash nucleate cracks due to the thermal fatigue of the material of the disk. The features of the design of the brake discs were considered as well. On the basis of the calculation and the experimental data we have shown a correlation between the emissivity of brushed and polished surfaces and their areas in the disk-to-pad brakes when using solid and self-ventilated discs

  7. 人工颈椎间盘置换术治疗脊髓型颈椎病的近期疗效%Short-term efficacy of Bryan cervical disc arthroplasty in patients with cervical spondylotic myelopathy

    梁英杰; 钟润泉; 郭东明; 温世锋


    目的:探讨Bryan人工颈椎间盘置换术治疗脊髓型颈椎病的近期疗效。方法应用Bryan人工颈椎间盘置换术治疗26例脊髓型颈椎病患者,在术前及末次随访时的颈椎X线片上测量置换节段矢状位、冠状位活动度。应用JOA评分评价术后神经功能。结果术后患者症状均明显缓解。26例均获随访,时间29~48个月。末次随访JOA评分由术前平均8.3分±4.6分增加到16.1分±5.3分,置换节段矢状位活动范围4.3°~7.2°(5.6°±2.4°);冠状位左右侧屈活动范围分别为3.1°~4.3°(3.8°±1.1°)和3.1°~4.6°(3.9°±0.9°)。随访期间假体无偏移松动或下沉,无置换节段假体周围异位骨化。结论 Bryan人工颈椎间盘置换术治疗脊髓型颈椎病近期临床效果较好,维持颈椎正常的活动范围、生理曲度和较好的生物力学稳定性。%Objective To discuss the short-term clinical and radiographic outcome of Bryan cervical disc arthroplas-ty.Methods Radiographic and clinical outcomes in 26 patients who received the Bryan cervical disc prosthesis were retrospectively reviewed.Static and dynamic X-ray was taken for measuring the range of motion.Clinical outcomes were assessed using Japanese Orthopedics Academy (JOA)scale.Results The average follow-up time was 29~48 months,and all patients were satisfied with the relief of symptoms.In the last follow-up,the average JOA scale was 16.1 ±5.3 ,while it was 8.3 ±4.6 pre-operation.The sagittal range of motion was 4.3°~7.2°(5.6°±2.4°),and the coronal range of motion was 3.1°~4.3°(3.8°±1.1°)and 3.1°~4.6°(3.9°±0.9°).No heterotopic ossifica-tion,prosthesis loosening,prosthesis migration or other complications occured.Conclusions Arthroplasty using the Bryan disc for cervical spondylotic myelopathy patients seems to be safe and provids encouraging clinical and radiolog-ic outcome in our short-term study.

  8. Design and Development of Micro-Power Generating Device for Biomedical Applications of Lab-on-a-Disc.

    Karunan Joseph

    Full Text Available The development of micro-power generators for centrifugal microfluidic discs enhances the platform as a green point-of-care diagnostic system and eliminates the need for attaching external peripherals to the disc. In this work, we present micro-power generators that harvest energy from the disc's rotational movement to power biomedical applications on the disc. To implement these ideas, we developed two types of micro-power generators using piezoelectric films and an electromagnetic induction system. The piezoelectric-based generator takes advantage of the film's vibration during the disc's rotational motion, whereas the electromagnetic induction-based generator operates on the principle of current generation in stacks of coil exposed to varying magnetic flux. We have successfully demonstrated that at the spinning speed of 800 revolutions per minute (RPM the piezoelectric film-based generator is able to produce up to 24 microwatts using 6 sets of films and the magnetic induction-based generator is capable of producing up to 125 milliwatts using 6 stacks of coil. As a proof of concept, a custom made localized heating system was constructed to test the capability of the magnetic induction-based generator. The heating system was able to achieve a temperature of 58.62 °C at 2200 RPM. This development of lab-on-a-disc micro power generators preserves the portability standards and enhances the future biomedical applications of centrifugal microfluidic platforms.

  9. 弹性盘型制动闸片装置振动特性研究%On Vibration Characteristics of Elastic Disc Brake Pad Device

    杨宽; 张济民


    设计了一种新型的具有弹性的盘型制动闸片装置,建立了低速的轨道车辆弹性盘型制动的数学模型,与无弹性的制动闸片进行了单轴制动特性的动态仿真比较.仿真结果表明,具有弹性的闸片制动时同样能够保证车辆的制动性能;在制动盘或闸片摩擦面有缺陷时,弹性闸片能有效降低闸片与制动盘间摩擦力引起的振动.该设计为盘型制动系统的设计及分析提供了新的思路.%A new elastic disc brake pad device is designed, and a mathematical model on low speed railway vehicle e-lastic disc brake is established to compare with the non-elastic brake pad by single wheel-set braking simulation. The result shows that the elastic brake pad can guarantee the vehicle braking performance as same as the non-elastic brake pad. When the disc or the friction surface of brake pad has some defects, elastic brake pad can effectively reduce the friction and the vibration between the brake pad and the brake disc. The design has been proved to be correct and rational, it will provide new ideas for the design and analysis of the disc brake system.

  10. The Use of Electronic Sensor Device to Augment Ligament Balancing Leads to a Lower Rate of Arthrofibrosis After Total Knee Arthroplasty.

    Geller, Jeffrey A; Lakra, Akshay; Murtaugh, Taylor


    Total knee arthroplasty (TKA) is a highly successful surgery shown to improve quality of life. One of the more common known complications of TKA is early arthrofibrosis requiring manipulation under anesthesia (MUA). This investigation evaluates the incidence of arthrofibrosis before and after the implementation of an electronic sensor device used to assist with ligament balancing. Six hundred ninety TKAs performed without sensor use were compared to a cohort of 252 TKAs performed with sensor usage. Prior to usage, there was a 5% rate of MUA after TKA, while after implementation, the MUA rate went down to 1.6% (P = .004). Ligament balancing using sensor assistance led to a statistically significant decrease in MUA in this cohort of patients. An odds ratio analysis also demonstrated that non-sensor patients had a 3.2× higher likelihood of requiring MUA than the sensor patients. The use of an electronic sensor device during trialing of TKA with resultant improved ligamentous balancing led to a statistically significant reduction in the rate of MUA in this cohort of patients. This type of approach to ligamentous balancing may continue to show evidence of improved clinical outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. The NEtherlands Cervical Kinematics (NECK) Trial. Cost-effectiveness of anterior cervical discectomy with or without interbody fusion and arthroplasty in the treatment of cervical disc herniation; A double-blind randomised multicenter study

    M.P. Arts (Mark); R. Brand (René); B.W. Koes (Bart); W.C. Peul (Wilco); M.E. van den Akker (Elske)


    textabstractBackground. Patients with cervical radicular syndrome due to disc herniation refractory to conservative treatment are offered surgical treatment. Anterior cervical discectomy is the standard procedure, often in combination with interbody fusion. Accelerated adjacent disc degeneration is

  12. Postero-Lateral Disc Prosthesis Combined With a Unilateral Facet Replacement Device Maintains Quantity and Quality of Motion at a Single Lumbar Level

    Nayak, Aniruddh N.; Doarn, Michael C.; Gaskins, Roger B.; James, Chris R.; Cabezas, Andres F.; Castellvi, Antonio E.


    Background Mechanically replacing one or more pain generating articulations in the functional spinal unit (FSU) may be a motion preservation alternative to arthrodesis at the affected level. Baseline biomechanical data elucidating the quantity and quality of motion in such arthroplasty constructs is non-existent. Purpose The purpose of the study was to quantify the motion-preserving effect of a posterior total disc replacement (PDR) combined with a unilateral facet replacement (FR) system at a single lumbar level (L4-L5). We hypothesized that reinforcement of the FSU with unilateral FR to replace the resected, native facet joint following PDR implantation would restore quality and quantity of motion and additionally not change biomechanics at the adjacent levels. Study Design In-vitro study using human cadaveric lumbar spines. Methods Six (n = 6) cadaveric lumbar spines (L1-S1) were evaluated using a pure-moment stability testing protocol (±7.5 Nm) in flexion-extension (F/E), lateral bending (LB) and axial rotation (AR). Each specimen was tested in: (1) intact; (2) unilateral FR; and (3) unilateral FR + PDR conditions. Index and adjacent level ROM (using hybrid protocol) were determined opto-electronically. Interpedicular travel (IPT) and instantaneous center of rotation (ICR) at the index level were radiographically determined for each condition. ROM, ICR, and IPT measurements were compared (repeated measures ANOVA) between the three conditions. Results Compared to the intact spine, no significant changes in F/E, LB or AR ROM were identified as a result of unilateral FR or unilateral FR + PDR. No significant changes in adjacent L3-L4 or L5-S1 ROM were identified in any loading mode. No significant differences in IPT were identified between the three test conditions in F/E, LB or AR at the L4-L5 level. The ICRs qualitatively were similar for the intact and unilateral FR conditions and appeared to follow placement (along the anterior-posterior (AP) direction) of

  13. Artroplastia total de disco cervical com prótese de Bryan: resultados clínicos e funcionais Artroplastía cervical total con prótesis de Bryan: resultados clínicos y funcionales Cervical total disc arthroplasty with Bryan disc: clinical and functional outcomes

    Eduardo Machado de Menezes


    resultados buenos y excelentes, 10% satisfactorios y el 7% malos. Hubo sólo una complicación (3%, que se revirtió con artrodesis anterior. CONCLUSIONES: La artroplastia discal cervical ha demostrado ser un método seguro y eficaz para el tratamiento de casos seleccionados de hernia de disco cervical asociada a la radiculopatía y/o a compresión de la médula espinal en el corto y mediano plazo.OBJECTIVE: To evaluate results of cervical disc arthroplasty with the Bryan prosthesis for treatment of cervicobrachial pain (radiculopathy and spinal cord compression (myelopathy. METHODS: From 2002 to 2007, the CECOL surgical staff has operated 65 patients. Only 28 patients were found in 2010 to a new data collection. The pre- and post-operative evaluation was conducted using the CSOQ questionnaire (Cervical Spine Outcomes Questionnaire. Odom criteria were used only in the postoperative evaluation. Both were translated and adapted to local culture. RESULTS: There was a significant symptomatic and functional improvement in most patients. The reduction of neck pain (axial and brachial pain (radicular was similar. Odom criteria showed 82.1% good and excellent results, 10% satisfactory and 7% poor. There was only one complication (3% which was reversed with anterior arthrodesis. CONCLUSIONS: The total cervical disc arthroplasty has proved to be a safe and effective method to treat selected cases of cervical disc herniation with radiculopathy and/or myelopathy in the short and medium term.

  14. Artificial disc and vertebra system: a novel motion preservation device for cervical spinal disease after vertebral corpectomy

    Dong, Jun; Lu, Meng; Lu, Teng; Liang, Baobao; Xu, Junkui; Qin, Jie; Cai, Xuan; Huang, Sihua; Wang, Dong; Li, Haopeng; He, Xijing


    OBJECTIVE: To determine the range of motion and stability of the human cadaveric cervical spine after the implantation of a novel artificial disc and vertebra system by comparing an intact group and a fusion group. METHODS: Biomechanical tests were conducted on 18 human cadaveric cervical specimens. The range of motion and the stability index range of motion were measured to study the function and stability of the artificial disc and vertebra system of the intact group compared with the fusion group. RESULTS: In all cases, the artificial disc and vertebra system maintained intervertebral motion and reestablished vertebral height at the operative level. After its implantation, there was no significant difference in the range of motion (ROM) of C3–7 in all directions in the non-fusion group compared with the intact group (p>0.05), but significant differences were detected in flexion, extension and axial rotation compared with the fusion group (pvertebra system could restore vertebral height and preserve the dynamic function of the surgical area and could theoretically reduce the risk of adjacent segment degeneration compared with the anterior fusion procedure. However, our results should be considered with caution because of the low power of the study. The use of a larger sample should be considered in future studies. PMID:26222819

  15. Frisbee - the first artificial cervical disc of 3RD generation

    Karin Büttner-Janz


    Full Text Available OBJECTIVE: The current cervical disc arthroplasty is limited by postoperative facet joint arthritis, heterotopic ossification and segmental kyphosis. The total Frisbee disc, which has an upper convex/concave non-spherical surface and a lower flat sliding surface, is a new approach for improved outcomes. Prior to clinical application, safety and suitability tests are required. METHODS: The Frisbee is the first 3rd generation disc according to a new classification of total disc because it can precisely mimic the segmental ROM, including the soft limitation of axial rotation. The ISO 18192-1 test was carried out to determine the rate of wear debris. A FE model was used to assess the safety of prosthetic components. In the sagittal plane several variables to determine the most favorable lordotic angle were evaluated. RESULTS: Two angled prosthetic plates are safer than one sliding angled core to prevent the displacement. The lordosis of 7° of the Frisbee leads to kyphosis of no more than 2° without reduction of the ROM. The wear rate of the Frisbee is five times smaller compared to an FDA-approved disc with a spherical sliding surface. CONCLUSIONS: Based on the test results, the clinical application of Frisbee can now be studied. The postoperative kyphosis observed with other devices is not an issue with the Frisbee design. Physiological ROM is combined with the significant reduction of wear debris. For these reasons the Frisbee has the potential to provide a better balanced segmental loading reducing the degeneration of the joint surface and heterotopic ossification.

  16. Total ankle arthroplasty: An imaging overview

    Kim, Da Rae; Choi, Yun Sun; Chun, Ka Young; Jung, Yoon Young; Kim, Jin Su; Young, Ki Won [Eulji Hospital, Eulji University, Seoul (Korea, Republic of); Potter, Hollis G.; Li, Angela E. [Dept. of Radiology and Imaging, Hospital for Special Surgery, New York (United States)


    With advances in implant technology, total ankle arthroplasty (TAA) has become an increasingly popular alternative to arthrodesis for the management of end-stage ankle arthritis. However, reports in the literature do not focus on the imaging features of TAA. Through a literature review, we demonstrate basic design features of the current ankle arthroplasty system, and the normal and abnormal postoperative imaging features associated with such devices. Pre- and postoperative evaluations of ankle arthroplasty mainly include radiography; in addition, computed tomography and magnetic resonance imaging provide further characterization of imaging abnormalities. Familiarization with multimodal imaging features of frequent procedural complications at various postoperative intervals is important in radiological practice.

  17. Total Ankle Arthroplasty: An Imaging Overview.

    Kim, Da-Rae; Choi, Yun Sun; Potter, Hollis G; Li, Angela E; Chun, Ka-Young; Jung, Yoon Young; Kim, Jin-Su; Young, Ki-Won


    With advances in implant technology, total ankle arthroplasty (TAA) has become an increasingly popular alternative to arthrodesis for the management of end-stage ankle arthritis. However, reports in the literature do not focus on the imaging features of TAA. Through a literature review, we demonstrate basic design features of the current ankle arthroplasty system, and the normal and abnormal postoperative imaging features associated with such devices. Pre- and postoperative evaluations of ankle arthroplasty mainly include radiography; in addition, computed tomography and magnetic resonance imaging provide further characterization of imaging abnormalities. Familiarization with multimodal imaging features of frequent procedural complications at various postoperative intervals is important in radiological practice.

  18. Lumbar spine disc height and curvature responses to an axial load generated by a compression device compatible with magnetic resonance imaging

    Kimura, S.; Steinbach, G. C.; Watenpaugh, D. E.; Hargens, A. R.


    STUDY DESIGN: Axial load-dependent changes in the lumbar spine of supine healthy volunteers were examined using a compression device compatible with magnetic resonance imaging. OBJECTIVE: To test two hypotheses: Axial loading of 50% body weight from shoulder to feet in supine posture 1) simulates the upright lumbar spine alignment and 2) decreases disc height significantly. SUMMARY OF BACKGROUND DATA: Axial compression on the lumbar spine has significantly narrowed the lumbar dural sac in patients with sciatica, neurogenic claudication or both. METHODS: Using a device compatible with magnetic resonance imaging, the lumbar spine of eight young volunteers, ages 22 to 36 years, was axially compressed with a force equivalent to 50% of body weight, approximating the normal load on the lumbar spine in upright posture. Sagittal lumbar magnetic resonance imaging was performed to measure intervertebral angle and disc height before and during compression. RESULTS: Each intervertebral angle before and during compression was as follows: T12-L1 (-0.8 degrees +/- 2.5 degrees and -1.5 degrees +/- 2.6 degrees ), L1-L2 (0.7 degrees +/- 1.4 degrees and 3.3 degrees +/- 2.9 degrees ), L2-L3 (4.7 degrees +/- 3.5 degrees and 7.3 degrees +/- 6 degrees ), L3-L4 (7.9 degrees +/- 2.4 degrees and 11.1 degrees +/- 4.6 degrees ), L4-L5 (14.3 degrees +/- 3.3 degrees and 14.9 degrees +/- 1.7 degrees ), L5-S1 (25.8 degrees +/- 5.2 degrees and 20.8 degrees +/- 6 degrees ), and L1-S1 (53.4 degrees +/- 11.9 degrees and 57.3 degrees +/- 16.7 degrees ). Negative values reflect kyphosis, and positive values reflect lordosis. A significant difference between values before and during compression was obtained at L3-L4 and L5-S1. There was a significant decrease in disc height only at L4-L5 during compression. CONCLUSIONS: The axial force of 50% body weight in supine posture simulates the upright lumbar spine morphologically. No change in intervertebral angle occurred at L4-L5. However, disc height at L4-L

  19. Artificial disc and vertebra system: a novel motion preservation device for cervical spinal disease after vertebral corpectomy

    Jun Dong


    Full Text Available OBJECTIVE: To determine the range of motion and stability of the human cadaveric cervical spine after the implantation of a novel artificial disc and vertebra system by comparing an intact group and a fusion group. METHODS: Biomechanical tests were conducted on 18 human cadaveric cervical specimens. The range of motion and the stability index range of motion were measured to study the function and stability of the artificial disc and vertebra system of the intact group compared with the fusion group. RESULTS: In all cases, the artificial disc and vertebra system maintained intervertebral motion and reestablished vertebral height at the operative level. After its implantation, there was no significant difference in the range of motion (ROM of C3-7 in all directions in the non-fusion group compared with the intact group (p>0.05, but significant differences were detected in flexion, extension and axial rotation compared with the fusion group (p<0.05. The ROM of adjacent segments (C3-4, C6-7 of the non-fusion group decreased significantly in some directions compared with the fusion group (p<0.05. Significant differences in the C4-6 ROM in some directions were detected between the non-fusion group and the intact group. In the fusion group, the C4-6 ROM in all directions decreased significantly compared with the intact and non-fusion groups (p<0.01. The stability index ROM (SI-ROM of some directions was negative in the non-fusion group, and a significant difference in SI-ROM was only found in the C4-6 segment of the non-fusion group compared with the fusion group. CONCLUSION: An artificial disc and vertebra system could restore vertebral height and preserve the dynamic function of the surgical area and could theoretically reduce the risk of adjacent segment degeneration compared with the anterior fusion procedure. However, our results should be considered with caution because of the low power of the study. The use of a larger sample should be

  20. The Mobi-C cervical disc for one-level and two-level cervical disc replacement: a review of the literature

    Alvin MD


    Full Text Available Matthew D Alvin,1,2 Thomas E Mroz1,3,41Cleveland Clinic Center for Spine Health, Cleveland Clinic, Cleveland, OH, USA; 2Case Western Reserve University School of Medicine, Cleveland, OH, USA; 3Cleveland Clinic Lerner College of Medicine, Cleveland, OH, USA; 4Department of Neurological Surgery, Cleveland Clinic, Cleveland, OH, USABackground: Cervical disc arthroplasty (CDA is a novel motion-preserving procedure that is an alternative to fusion. The Mobi-C disc prosthesis, one of many Food and Drug Administration (FDA-approved devices for CDA, is the only FDA-approved prosthesis for two-level CDA. Hence, it may allow for improved outcomes compared with multilevel fusion procedures.Purpose: To critically assess the available literature on CDA with the Mobi-C prosthesis, with a focus on two-level CDA.Methods: All clinical articles involving the Mobi-C disc prosthesis for CDA through September 1, 2014 were identified on Medline. Any paper that presented Mobi-C CDA clinical results was included. Study design, sample size, length of follow-up, use of statistical analysis, quality of life outcome scores, conflict of interest, and complications were recorded.Results: Fifteen studies were included that investigated Mobi-C CDA, only one of which was a level Ib randomized control trial. All studies included showed non-inferiority of one-level Mobi-C CDA to one-level anterior cervical discectomy and fusion (ACDF. Only one study analyzed outcomes of one-level versus two-level Mobi-C CDA, and only one study analyzed two-level Mobi-C CDA versus two-level ACDF. In comparison with other cervical disc prostheses, the Mobi-C prosthesis is associated with higher rates of heterotopic ossification (HO. Studies with conflicts of interest reported lower rates of HO. Adjacent segment degeneration or disease, along with other complications, were not assessed in most studies.Conclusion: One-level Mobi-C CDA is non-inferior, but not superior, to one-level ACDF for patients

  1. Current concepts in elbow arthroplasty.

    Bachman, Daniel; Cil, Akin


    Distal humeral replacement and the total elbow are two commonly-used arthroplastiesEach prosthesis has evolving indications and surgical techniquesRecent changes in device design and implantation methods are due to biomechanical and clinical outcome-based researchNew prostheses and methods provide: better elbow kinematics, more durable bearings and longer-lasting joint replacement potential Cite this article: EFORT Open Rev 2017;2:83-88. DOI: 10.1302/2058-5241.2.160064.

  2. Local and global subaxial cervical spine biomechanics after single-level fusion or cervical arthroplasty.

    Finn, Michael A; Brodke, Darrel S; Daubs, Michael; Patel, Alpesh; Bachus, Kent N


    An experimental in vitro biomechanical study was conducted on human cadaveric spines to evaluate the motion segment (C4-C5) and global subaxial cervical spine motion after placement of a cervical arthroplasty device (Altia TDI,Amedica, Salt Lake City, UT) as compared to both the intact spine and a single-level fusion. Six specimens (C2-C7) were tested in flexion/extension, lateral bending, and axial rotation under a +/- 1.5 Nm moment with a 100 N axial follower load. Following the intact spine was tested; the cervical arthroplasty device was implanted at C4-C5 and tested. Then, a fusion using lateral mass fixation and an anterior plate was simulated and tested. Stiffness and range of motion (ROM) data were calculated. The ROM of the C4-C5 motion segment with the arthroplasty device was similar to that of the intact spine in flexion/extension and slightly less in lateral bending and rotation, while the fusion construct allowed significantly less motion in all directions. The fusion construct caused broader effects of increasing motion in the remaining segments of the subaxial cervical spine, whereas the TDI did not alter the adjacent and remote motion segments. The fusion construct was also far stiffer in all motion planes than the intact motion segment and the TDI, while the artificial disc treated level was slightly stiffer than the intact segment. The Altia TDI allows for a magnitude of motion similar to that of the intact spine at the treated and adjacent levels in the in vitro setting.

  3. The effect of different design concepts in lumbar total disc arthroplasty on the range of motion, facet joint forces and instantaneous center of rotation of a L4-5 segment.

    Schmidt, Hendrik; Midderhoff, Stefan; Adkins, Kyle; Wilke, Hans-Joachim


    Although both unconstrained and constrained core lumbar artificial disc designs are in clinical use, the effect of their design on the range of motion, center of rotations, and facet joint forces is not well understood. It is assumed that the constrained configuration causes a fixed center of rotation with high facet forces, while the unconstrained configuration leads to a moving center of rotation with lower loaded facets. The authors disagree with both assumptions and hypothesized that the two different designs do not lead to substantial differences in the results. For the different implant designs, a three-dimensional finite element model was created and subsequently inserted into a validated model of a L4-5 lumbar spinal segment. The unconstrained design was represented by two implants, the Charité disc and a newly developed disc prosthesis: Slide-Disc. The constrained design was obtained by a modification of the Slide-Disc whereby the inner core was rigidly connected to the lower metallic endplate. The models were exposed to an axial compression preload of 1,000 N. Pure unconstrained moments of 7.5 Nm were subsequently applied to the three anatomical main planes. Except for extension, the models predicted only small and moderate inter-implant differences. The calculated values were close to those of the intact segment. For extension, a large difference of about 45% was calculated between both Slide-Disc designs and the Charité disc. The models predicted higher facet forces for the implants with an unconstrained core compared to an implant with a constrained core. All implants caused a moving center of rotation. Except for axial rotation, the unconstrained and constrained configurations mimicked the intact situation. In axial rotation, only the Slide- Disc with mobile core reproduced the intact behavior. Results partially support our hypothesis and imply that different implant designs do not lead to strong differences in the range of motion and the location

  4. Factors affecting reoperations after anterior cervical discectomy and fusion within and outside of a Federal Drug Administration investigational device exemption cervical disc replacement trial.

    Singh, Kern; Phillips, Frank M; Park, Dan K; Pelton, Miguel A; An, Howard S; Goldberg, Edward J


    The excellent clinical results of five US Federal Drug Administration (FDA) trials approved for cervical total disc replacement (TDR) (Prestige [Medtronic Sofamor Danek, Memphis, TN, USA], Bryan [Medtronic Sofamor Danek], ProDisc-C [Synthes, West Chester, PA, USA], Kineflex|C [SpinalMotion, Mountain View, CA, USA], and Mobi-C [LDR Spine, Austin, TX, USA]) have recently been published. In these prospective randomized studies, superiority or equivalency of TDR was claimed, citing an 8.7% (23/265), 9.5% (21/221), 8.5% (9/106), 12.2% (14/115), and 6.2% (5/81) (mean = 9.02%) rate of additional related cervical surgical procedures within 2 years in control anterior cervical discectomy and fusion (ACDF) patients, respectively, compared with 1.8% (5/276), 5.8% (14/242), 1.9% (2/103), 11% (15/136), and 1.2% (2/164) (mean = 4.34%) in patients receiving the cervical TDR. The rate of reoperation within 2 years after ACDF seems unusually high. To assess the rate of and specific indications for early reoperation after ACDF in a cohort of patients receiving the ACDF as part of their customary care. These results are contrasted with similar patients receiving ACDF as the control arm of five FDA investigational device exemption (IDE) studies. Multisurgeon retrospective clinical series from a single institution. One hundred seventy-six patients with spondylotic radiculopathy or myelopathy underwent ACDF by three surgeons between 2001 and 2005 as part of their clinical practices. All patients had at least 2 years of follow-up with final follow-up within 6 months of completion of this study. Cervical reoperation rates at 2-year follow-up and at 3.5-year follow-up. Review of medical records and telephone conversations were completed to determine the number of patients who had undergone a revision cervical procedure. At final follow-up, complete data were available for 159 ACDF patients. Of the 48 patients who underwent single-level ACDF and met criteria for inclusion in the IDE studies

  5. Revision rate of Birmingham Hip Resurfacing arthroplasty: comparison of published literature and arthroplasty register data.

    Schuh, Reinhard; Neumann, Daniel; Rauf, Rauend; Hofstaetter, Jochen; Boehler, Nikolaus; Labek, Gerold


    Hip resurfacing arthroplasty has gained popularity for treating young and active patients who have arthritis. There are two major data sources for assessing outcome and revision rate after total joint arthroplasty: sample-based clinical trials and national arthroplasty registers. The purpose of this study was to evaluate the outcome of the Birmingham Hip Resurfacing (BHR) arthroplasty in terms of revision rate as reported in clinical studies and recorded by national arthroplasty registers. A comprehensive literature research was performed from English-language, peer-reviewed journals and annual reports from national joint arthroplasty registers worldwide. Only publications from MEDLINE-listed journals were included. The revision rate was used as the primary outcome parameter. In order to allow for direct comparison of different data sets, calculation was based on revisions per 100 observed component years. For statistical analysis, confidence intervals (CI) were calculated. A total of 18,708 implants, equivalent to 106,565 observed component years, were analysed in the follow-up studies. The register reports contained 9,806 primary cases corresponding to 44,294 observed component years. Statistical analysis revealed a significant difference in revisions per 100 observed component years between the development team (0.27; CI: 0.14-0.40) and register data (0.74; CI: 0.72-0.76). The BHR arthroplasty device shows good results in terms of revision rate in register data as well as in clinical studies. However, the excellent results reported by the development team are not reproducible by other surgeons. Based on the results of our study, we believe that comprehensive national arthroplasty registers are the most suitable tool for assessing hip arthroplasty revision rate.

  6. 人工颈椎间盘与颈椎动态稳定器治疗颈椎病的早中期临床疗效和影像学分析%A comparison of cervical disc arthroplasty versus dynamic cervial implant in the treatment of cervical spondylopathy:a clinical and radiological study

    关立; 陈小龙; 海涌; 刘玉增; 汪文龙; 于志毅


    ;两组患者术后6个月和末次随访与术前比较,差异均有统计学意义(P<0.01),但两组间术前及术后末次随访时差异无统计学意义(P>0.05);两组患者术前、术后6个月及末次随访时对比,手术节段椎间隙高度、手术节段和相邻节段椎间活动度差异无统计学意义(P>0.05)。Prodisc-C 组术后末次随访发现3例异位骨化,2例假体前移1 mm,DCI 组未出现异位骨化和假体移动。结论 Prodisc-C 人工颈椎间盘与 DCI 治疗颈椎病均能保留颈椎活动度,恢复和维持椎间隙高度和颈椎生理弧度,早中期疗效满意。%Objective To evaluate the clinical and radiological outcomes of cervical disc arthroplasty by Prodisc-C versus dynamic cervial implant ( DCI ) in the treatment of cervical spondylopathy.Methods All cervical spondylopathy cases undergoing cervical disc arthroplasty by Prodisc-C or dynamic cervial implant between February 2011 and February 2013 were analyzed retrospectively. There were 16 patients in anterior cervical disc arthroplasty group ( male 8, female 8 ). Age averaged 44 years ( range: 32-54 years ). There were 10 cases with cervical spondylotic myelopathy, and 6 cases with radicular spondylosis. In dynamic cervical implant group were 10 cases ( male 6, female 4 ). Age averaged 44.5 years ( range: 33-55 years ). There were 7 cases of cervical spondylotic myelopathy, and 3 cases of radicular spondylosis. Parameters as gender, age, operation time and blood loss of all the patients were analyzed. The patients were followed 1 month, 3 months, 6 months, 12 months and 24 months postoperatively. Neck disability index ( NDI ), Japanese Orthopaedic Association ( JOA ) Score and Visual Analogue Scale ( VAS ) were used to evaluate the clinical outcomes of the two groups. Anterioposterior and lateral X-ray, hyperextension and hyperflexion X-ray films before and after surgery were analyzed and cervical lordosis, the height of disc, range of motion


    Filho, Geraldo Motta; Galvão, Marcus Vinicius; Monteiro, Martim; Cohen, Marcio; Brandão, Bruno


    The study's objective is to evaluate the characteristics and problems of patients who underwent shoulder arthroplasties between July 2004 and November 2006. Methodology: During the period of the study, 145 shoulder arthroplasties were performed. A prospective protocol was used for every patient; demographic, clinical and surgical procedure data were collected. All gathered data were included in the data base. The patients were divided in three major groups: fractures, degenerative diseases and trauma sequels. Information obtained from the data base was correlated in order to determine patients' epidemiologic, injuries, and surgical procedure profiles. Results: Of the 145 shoulder arthroplasties performed, 37% presented trauma sequels, 30% degenerative diseases, and 33% proximal humerus fracture. 12% of the cases required total arthroplasties and 88% partial arthroplasties. Five major complications were observed on early postoperative period. Conclusion: Shoulder arthroplasties have become a common procedure in orthopaedic practice. Surgical records are important in evidencing progressive evolution and in enabling future clinical outcomes evaluation. PMID:26998463

  8. Hip resurfacing arthroplasty


    Background and purpose Hip resurfacing arthroplasty is claimed to allow higher activity levels and to give better quality of life than total hip arthroplasty. In this literature review, we assessed the therapeutic value of hip resurfacing arthroplasty as measured by functional outcome. Methods An extensive literature search was performed using the PubMed, Embase, and Cochrane databases. Results 9 patient series, 1 case-control study, and 1 randomized controlled trial (RCT) were included. Clin...

  9. Revision Total Elbow Arthroplasty.

    Ramirez, Miguel A; Cheung, Emilie V; Murthi, Anand M


    Despite recent technologic advances, total elbow arthroplasty has complication rates higher than that of total joint arthroplasty in other joints. With new antirheumatic treatments, the population receiving total elbow arthroplasty has shifted from patients with rheumatoid arthritis to those with posttraumatic arthritis, further compounding the high complication rate. The most common reasons for revision include infection, aseptic loosening, fracture, and component failure. Common mechanisms of total elbow arthroplasty failure include infection, aseptic loosening, fracture, component failure, and instability. Tension band fixation, allograft struts with cerclage wire, and/or plate and screw constructs can be used for fracture stabilization.

  10. Cross-shear implementation in sliding-distance-coupled finite element analysis of wear in metal-on-polyethylene total joint arthroplasty: intervertebral total disc replacement as an illustrative application.

    Goreham-Voss, Curtis M; Hyde, Philip J; Hall, Richard M; Fisher, John; Brown, Thomas D


    Computational simulations of wear of orthopaedic total joint replacement implants have proven to valuably complement laboratory physical simulators, for pre-clinical estimation of abrasive/adhesive wear propensity. This class of numerical formulations has primarily involved implementation of the Archard/Lancaster relationship, with local wear computed as the product of (finite element) contact stress, sliding speed, and a bearing-couple-dependent wear factor. The present study introduces an augmentation, whereby the influence of interface cross-shearing motion transverse to the prevailing molecular orientation of the polyethylene articular surface is taken into account in assigning the instantaneous local wear factor. The formulation augment is implemented within a widely utilized commercial finite element software environment (ABAQUS). Using a contemporary metal-on-polyethylene total disc replacement (ProDisc-L) as an illustrative implant, physically validated computational results are presented to document the role of cross-shearing effects in alternative laboratory consensus testing protocols. Going forward, this formulation permits systematically accounting for cross-shear effects in parametric computational wear studies of metal-on-polyethylene joint replacements, heretofore a substantial limitation of such analyses.

  11. Unicompartmental knee arthroplasty

    Kort, Nanne Pieter


    This thesis concerns technical aspects of unicompartmental knee arthroplasty. Recent years have witnessed a resurgence of interest in unicompartmental arthroplasty, particularly with the introduction of the minimally invasive technique. In the light of the excellent long-term results of the total kn

  12. Effects of controlled dynamic disc distraction on degenerated intervertebral discs: an in vivo study on the rabbit lumbar spine model.

    Kroeber, Markus; Unglaub, Frank; Guehring, Thorsten; Guegring, Thorsten; Nerlich, Andreas; Hadi, Tamer; Lotz, Jeffrey; Carstens, Claus


    An in vivo study on the rabbit lumbar spine model. Effects of temporary dynamic distraction on intervertebral discs were studied on the lumbar spine rabbit model to characterize the changes associated with disc distraction and to evaluate feasibility of temporary disc distraction to previously compressed discs in order to stimulate disc regeneration. Studies have shown that accelerated degeneration of the intervertebral disc results from altered mechanical loading conditions. The development of methods for the prevention of disc degeneration and the restoration of disc tissue that has already degenerated are needed. New Zealand white rabbits (n = 32) were used for this study. The rabbits were randomly assigned to one of five groups. In 12 animals, the discs were first loaded for 28 days using a custom-made external loading device to stimulate disc degeneration. After 28 days loading time, the discs in six animals were distracted for 7 days and in six animals for 28 days using the same external device, however, modified as dynamic distraction device. In six animals, the discs were distracted for 28 days without previous loading; and in six animals, the discs were loaded for 28 days and afterwards the loading device removed for 28 days for recovery without distraction. Six animals were sham operated. The external device was situated; however, the discs remained undistracted and they also served as controls. After 28 to 56 days loading and distraction time, the animals were killed and the lumbar spine was harvested for examination. Disc height, disc morphology, cell viability, relative neutral zone, and tangent modulus were measured. After 28 days of loading, the discs demonstrated a significant decrease in disc space. Histologically, disorganization of the architecture of the anulus occurred. The number of dead cells increased significantly in the anulus and cartilage endplate. These changes were reversible after 28 days of distraction. The disc thickness increased

  13. 颈椎人工椎间盘置换术与颈前路减压融合内固定术手术疗效比较%Comparing the effects of Bryan cervical Disc arthroplasty with anterior cervical decompres-sion and fusion

    张涛; 王弘; 徐宏光; 李从明


    目的:比较颈椎人工椎间盘置换术( cervical disc arthroplasty ,CDA)与颈前路减压融合内固定术( anterior cervical de-compression and fusion ,ACDF)的手术疗效。方法:回顾分析2012年8月~2015年1月收治的退变性颈椎病50例,随机给予CDA(n=23),或者ACDF(n=27)治疗,术后12个月门诊随访。结果:两组术前性别、年龄、手术节段活动度(range of motion, ROM)、VAS( visual analogue scale )及JOA( Japanese orthopaedic association )无统计学差异,CDA组比ACDF组手术时间短,出血量少,具有明显统计学差异( P<0.01),两组住院时间无明显统计学差异。术后12个月,两组手术节段ROM差异具有统计学意义( P<0.01),CDA组ROM较术前得以维持,ACDF组降低。两组JOA及VAS无统计学差异。结论:CDA较ACDF能维持手术节段的活动度,CDA有望取代ACDF。%Objective:To compare curative effects of Bryan cervical disc arthroplasty ( CDA) with those of anterior cervical decompression and fusion ( AC-DF).Methods:A total of 50 patients with cervical spondylotic myelopathy treated in our hospital between August 2012 and January 2015 were randomly as-signed to two groups.One group were treated with CDA (n=23) and another with ACDF(n=27).Two groups of patients were postoperatively followed on outpatient basis for 12 months.Results:The two groups were not significantly different regarding the gender,ages,range of cervical motion(ROM) and sco-ring on visual analogue scale(VAS) and Japanese Orthopedic Association(JOA).CDA group had shorter operative time and intraoperative blood loss than ACDF group,the difference was significant( P<0.01) .The length of hospital stay remained similar for the two groups ,yet the two groups were different con-cerning the ROM 12 month after operation(P<0.01).Postoperative ROM was maintained in patients in CDA group,whereas was decreased in ACDF group. There was no

  14. 盘式封堵器在管道抢险作业中的故障处理%Troubleshooting of disc plugging device in rush repair of pipeline

    陈瑞; 杨令彪; 徐晓刚; 霍帅军


    Disc plugging technology has been widely used in rush repairs of pipelines, however, faults may occur in disc plugging device due to some objective or subjective factors in actual application, which will result in a poor plugging. This paper introduces the equipment composition, technical principles and plugging process. Taking the rush repair of pipeline as an example, it proposes corresponding solutions to the faults due to non-feeding when opening hole of cutter, cutter sticking, fail to reach at position for the plug and that of plug at T-joint, etc., and analyzes the shortcomings of disc plugging device, and proposes improvement methods accordingly. It is considered that increasing the applicable pressure and pipe size of disc plugging device, and enlarging the applicable range of on-line plugging to allow the technology to be applicable in renovation, update and rush repair on the pipelines with different pressure are future development trend of disc plugging technology.%盘式封堵技术广泛应用于管道抢修,但在实际应用中,盘式封堵器会因一些客观或主观因素出现故障,影响封堵效果.介绍了盘式封堵器的设备组成、技术原理、施工工艺.以管道换管抢修为例,针对盘式封堵技术应用过程中可能出现的故障,如开孔时筒刀无法进给、卡刀、封堵头未送到位,封堵三通时塞堵无法入位等,给出了相应的解决方法.分析了盘式封堵器设备本身存在的缺陷,提出了改进方法.提升盘式封堵的适用压力和适用管径,扩展不停输封堵技术的应用范围,使之能够应用于中、高压管道的更新、改造、抢修等方面是盘式封堵技术今后的发展趋势.

  15. Bryan人工椎间盘置换术对颈椎曲度影响的研究%Effect of cervical arthroplasty with Bryan disc prosthesis on post-operative cervical curvature

    孙宇; 赵衍斌; 周非非; 张凤山; 潘胜发; 刘忠军


    Objective To investigate the angle changes of functional spine unit ( FSU) at operated segment after single-level Bryan disc replacement at different time points after operation. Methods A total of 60 patients receiving single-level Bryan disc replacement between December 2003 and December 2007 were enrolled in this study. The changes of FSU angle were measured and compared on lateral X-ray films. Results All 60 patients were followed up for an average of 32 months ( ranging 3-69 months). The levels of surgery included C3/C4 (2 cases), C4/C3 (14 cases) , C5/C6 (41 cases) and C6/C,7(3 cases). The mean FSU angle was 0. 3° before the surgery, and -0. 5° at the final follow-up, with statistically significant difference found between them ( P < 0.05 ). The patients were divided into three groups according the operation period: early stage group (2003-2004), middle stage group (2005) and late stage group (2006-2007). The average FSU kyphosis was increased by 1.6° after the operation in early stage group, but only by 0.1° in late stage group,and the difference had statistical significance ( P < 0.05 ). Conclusion FSU kyphosis mainly occurs in early stage after Bryan disc replacement. This complication could be avoided with surgical experience accumulation and surgical technique improvement.%目的 观察不同手术时期Bryan人工椎间盘置换术后置换节段脊柱功能单位(functional spine unit,FSU)曲度变化情况.方法 随访2003年12月~2007年12月接受单节段Bryan人工椎间盘置换术的患者,在侧位X线片上测量FSU角度变化.结果 60例患者获得随访,随访3~ 69个月,平均32个月,手术节段包括C3/C4节段2例,C4/C5节段14例,C5/C6节段41例,C6/C7节段3例.术前FSU平均曲度为0.3°,末次随访时为-0.5°(P<0.05).根据手术日期将全部病例分成早期(2003~ 2004年)、中期(2005年)和后期(2006 ~ 2007年)3维,统计分析发现早期病例随访时FSU后凸平均增加1.6°,后

  16. 21 CFR 872.3970 - Interarticular disc prosthesis (interpositional implant).


    ... implant). 872.3970 Section 872.3970 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3970 Interarticular disc prosthesis (interpositional implant). (a) Identification. An interarticular disc...

  17. Imaging of knee arthroplasty

    Miller, Theodore T. [Department of Radiology, North Shore University Hospital, 825 Northern Blvd., Great Neck, NY 11021 (United States)]. E-mail:


    Knee replacement surgery, either with unicompartmental or total systems, is common. The purpose of this manuscript is to review the appearance of normal knee arthroplasty and the appearances of complications such as infection, polyethylene wear, aseptic loosening and particle-induced osteolysis, patellofemoral abnormalities, axial instability, and periprosthetic and component fracture. Knowledge of the potential complications and their imaging appearances will help the radiologist in the diagnostic evaluation of the patient with a painful knee arthroplasty.

  18. Imaging of hip arthroplasty

    Miller, Theodore T., E-mail: [Department of Radiology and Imaging, Hospital for Special Surgery, 535 E. 70th Street, New York, NY 10021 (United States)


    The imaging evaluation of the prosthetic hip begins with radiography, but arthrography, aspiration, scintigraphy, sonography, CT and MR imaging all have roles in the evaluation of the painful prosthesis. This article will review the appearance of normal hip arthroplasty including hemiarthroplasty, total arthroplasty, and hip resurfacing, as well as the appearances of potential complications such as aseptic loosening and osteolysis, dislocation, infection, periprosthetic fracture, hardware failure, and soft tissue abnormalities.

  19. Broken discs: warp propagation in accretion discs

    Nixon, Chris; King, Andrew


    We simulate the viscous evolution of an accretion disc around a spinning black hole. In general any such disc is misaligned, and warped by the Lense-Thirring effect. Unlike previous studies we use effective viscosities constrained to be consistent with the internal fluid dynamics of the disc. We find that nonlinear fluid effects, which reduce the effective viscosities in warped regions, can promote the breaking of the disc into two distinct planes. This occurs when the Shakura & Sunyaev dimen...

  20. Failure of cervical arthroplasty in a patient with adjacent segment disease associated with Klippel-Feil syndrome

    Ioannis D Papanastassiou


    Full Text Available Cervical arthroplasty may be justified in patients with Klippel-Feil syndrome (KFS in order to preserve cervical motion. The aim of this paper is to report an arthroplasty failure in a patient with KFS. A 36-year-old woman with KFS underwent two-level arthroplasty for adjacent segment disc degeneration. Anterior migration of the cranial prosthesis was encountered 5 months postoperatively and was successfully revised with anterior cervical fusion. Cervical arthroplasty in an extensively stiff and fused neck is challenging and may lead to catastrophic failure. Although motion preservation is desirable in KFS, the special biomechanical features may hinder arthroplasty. Fusion or hybrid constructs may represent more reasonable options, especially when multiple fused segments are present.

  1. Arthroplasty register for Germany

    Hagen, Anja


    Full Text Available Scientific background: The annual number of joint replacement operations in Germany is high. The introduction of an arthroplasty register promises an important contribution to the improvement of the quality of patient’s care. Research questions: The presented report addresses the questions on organization and functioning, benefits and cost-benefits as well as on legal, ethical and social aspects of the arthroplasty registers. Methods: A systematic literature search was conducted in September 2008 in the medical databases MEDLINE, EMBASE etc. and was complemented with a hand search. Documents describing arthroplasty registers and/or their relevance as well as papers on legal, ethical and social aspects of such registers were included in the evaluation. The most important information was extracted and analysed. Results: Data concerning 30 arthroplasty registers in 19 countries as well as one international arthroplasty register were identified. Most of the arthroplasty registers are maintained by national orthopedic societies, others by health authorities or by their cooperation. Mostly, registries are financially supported by governments and rarely by other sources.The participation of the orthopedists in the data collection process of the arthroplasty registry is voluntary in most countries. The consent of the patients is usually required. The unique patient identification is ensured in nearly all registers.Each data set consists of patient and clinic identification numbers, data on diagnosis, the performed intervention, the operation date and implanted prostheses. The use of clinical scores, patient-reported questionnaires and radiological documentation is rare. Methods for data documentation and transfer are paper form, electronic entry as well as scanning of the data using bar codes. The data are mostly being checked for their completeness and validity. Most registers offer results of the data evaluation to the treating orthopedists and

  2. Dynamic, six-axis stiffness matrix characteristics of the intact intervertebral disc and a disc replacement.

    Holsgrove, Timothy P; Gill, Harinderjit S; Miles, Anthony W; Gheduzzi, Sabina


    Thorough pre-testing is critical in assessing the likely in vivo performance of spinal devices prior to clinical use. However, there is a lack of data available concerning the dynamic testing of lumbar (porcine model) total disc replacements in all six axes under preload conditions. The aim of this study was to provide new data comparing porcine lumbar spinal specimen stiffness between the intact state and after the implantation of an unconstrained total disc replacement, in 6 degrees of freedom. The dynamic, stiffness matrix testing of six porcine lumbar isolated disc specimens was completed using triangle waves at a test frequency of 0.1 Hz. An axial preload of 500 N was applied during all testing. Specimens were tested both in the intact condition and after the implantation of the total disc replacement. Sixteen key stiffness terms were identified for the comparison of the intact and total disc replacement specimens, comprising the 6 principal stiffness terms and 10 key off-axis stiffness terms. The total disc replacement specimens were significantly different to the intact specimens in 12 of these key terms including all six principal stiffness terms. The implantation of the total disc replacement resulted in a mean reduction in the principal stiffness terms of 100%, 91%, and 98% in lateral bending, flexion-extension, and axial rotation, respectively. The novel findings of this study have demonstrated that the unconstrained, low-friction total disc replacement does not replicate the stiffness of the intact specimens. It is likely that other low-friction total disc replacements would produce similar results due to stiffness being actively minimised as part of the design of low-friction devices, without the introduction of stiffening elements or mechanisms to more accurately replicate the mechanical properties of the natural intervertebral disc. This study has demonstrated, for the first time, a method for the quantitative comparative mechanical function

  3. Modeling and Thermal Analysis of Disc

    Brake Praveena S; Lava Kumar M


    The disc brake is a device used for slowing or stopping the rotation of the vehicle. Number of times using the brake for vehicle leads to heat generation during braking event, such that disc brake undergoes breakage due to high Temperature. Disc brake model is done by CATIA and analysis is done by using ANSYS workbench. The main purpose of this project is to study the Thermal analysis of the Materials for the Aluminum, Grey Cast Iron, HSS M42, and HSS M2. A comparison between ...

  4. Total hip arthroplasty

    Slavković Nemanja


    Full Text Available Total hip arthroplasty is most common reconstructive hip procedure in adults. In this surgery we replace some parts of the upper femur and acetabulum with biocompatible materials. The main goal of this surgery is to eliminate pain and regain full extent of joint motion, maintaining hip stability. Surgical technique, biomaterials, design of the prosthesis and fixation techniques have evolved with time adjusting to each other. After total hip arthroplasty patients’ quality of life should be improved. There are many various postoperative complications. Some of them are fatal, and some are minor, which may become manifested years after surgery. Each next surgical procedure following previous hip surgery is associated with considerably lower chances to be successful. Therefore, in primary total hip arthroplasty, preoperative evaluation and preparation of patients are essential. Every orthopaedic surgeon needs to improve already adopted surgical skills applying them with precision and without compromise, with the main goal to achieve long-term durability of the selected implant. The number of total hip arthroplasties will also increase in future, and newer and higher quality materials will be used.

  5. Total knee arthroplasty

    Schrøder, Henrik M.; Petersen, Michael M.


    Total knee arthroplasty (TKA) is a successful treatment of the osteoarthritic knee, which has increased dramatically over the last 30 years. The indication is a painful osteoarthritic knee with relevant radiographic findings and failure of conservative measures like painkillers and exercise. Trea...

  6. Effects of unisegmental disc compression on adjacent segments: an in vivo animal model.

    Unglaub, Frank; Guehring, Thorsten; Lorenz, Helga; Carstens, Claus; Kroeber, Markus W


    It is controversial whether fusion of discs in the spine leads to increased degeneration on the remaining discs or whether the degenerative changes are merely a part of the inevitable natural history process. To determine the effects of unisegmental compression and subsequent recovery on adjacent segments, we studied histology, radiology and intradiscal pressure using an in vivo rabbit model. Fifteen New Zealand rabbits were divided in to three groups of five. In the first group, the intervertebral disc L4-L5 of the lumbar spine was axially loaded for 28 days with an external loading device. In the second group, the intervertebral disc was compressed for 28 days and allowed to recover for an equal amount of time, with the loading device removed. Five animals underwent a sham operation, in which the external loading device was situated, but their discs remained unloaded for 28 days. The intradiscal pressure was determined in the loaded discs as well as in the cranial and caudal adjacent discs. Lateral radiographs were taken from each subjected intervertebral disc with adjacent vertebral bodies and the cranial and caudal adjacent segments. The compressed discs showed lower intradiscal pressure in comparison with the control group, which remained unloaded. In the cranial and caudal discs adjacent to the loaded discs the average intradiscal pressure was similar to the unloaded controls. The loaded discs demonstrated a significant decrease in disc space. No discs adjacent to the loaded discs changed in height. The lamellar architecture of the inner, middle, and outer annulus became more disorganized in the loaded discs. The nucleus pulposus showed increase of mucoid degeneration and increased cell death. Intervertebral discs from the control group and the adjacent discs to the compressed discs maintained their normal morphology. This study shows that mechanical loading of discs in the spine can cause rapid degeneration. Adjacent discs, however, did not change in terms

  7. Dynamos in accretion discs

    Brandenburg, A.; von Rekowski, B.


    It is argued that accretion discs in young stellar objects may have hot coronae that are heated by magnetic reconnection. This is a consequence of the magneto-rotational instability driving turbulence in the disc. Magnetic reconnection away from the midplane leads to heating of the corona which, in turn, contributes to driving disc winds.

  8. Primary total elbow arthroplasty

    Suresh Kumar


    Full Text Available Background: Primary total elbow arthroplasty (TEA is a challenging procedure for orthopedic surgeons. It is not performed as frequently as compared to hip or knee arthroplasty. The elbow is a nonweight-bearing joint; however, static loading can create forces up to three times the body weight and dynamic loading up to six times. For elderly patients with deformity and ankylosis of the elbow due to posttraumatic arthritis or rheumatoid arthritis or comminuted fracture distal humerus, arthroplasty is one of the option. The aim of this study is to analyze the role of primary total elbow arthroplasty in cases of crippling deformity of elbow. Materials and Methods: We analyzed 11 cases of TEA, between December 2002 and September 2012. There were 8 females and 3 males. The average age was 40 years (range 30-69 years. The indications for TEA were rheumatoid arthritis, comminuted fracture distal humerus with intraarticular extension, and posttraumatic bony ankylosis of elbow joint. The Baksi sloppy (semi constrained hinge elbow prosthesis was used. Clinico-radiological followup was done at 1 month, 3 months, 6 months, 1 year, and then yearly basis. Results: In the present study, average supination was 70° (range 60-80° and average pronation was 70° (range 60-80°. Average flexion was 135° (range 130-135°. However, in 5 cases, there was loss of 15 to 35° (average 25° of extension (45° out of 11 cases. The mean Mayo elbow performance score was 95.4 points (range 70-100. Arm length discrepancy was only in four patients which was 36% out of 11 cases. Clinico-radiologically all the elbows were stable except in one case and no immediate postoperative complication was noted. Radiolucency or loosening of ulnar stem was seen in 2 cases (18% out of 11 cases, in 1 case it was noted after 5 years and in another after 10 years. In second case, revision arthroplasty was done, in which only ulnar hinge section, hinge screw and lock screw with hexagonal head

  9. Comparison of adjacent segment degeneration five years after single level cervical fusion and cervical arthroplasty:a retrospective controlled study

    SUN Yu; ZHAO Yan-bin; PAN Sheng-fa; ZHOU Fei-fei; CHEN Zhong-qiang; LIU Zhong-jun


    Background Cervical arthroplasty is indicated to preserve cervical motion and prevent accelerated adjacent segment degeneration.Whether accelerated adjacent segment degeneration is prevented in the long term is unclear.This trial compared adjacent segment degeneration in Bryan disc arthroplasty with that in anterior cervical decompression and fusion five years after the surgery.Methods We studied patients with single level degenerative cervical disc disease.The extent of adjacent segment degeneration was estimated from lateral X-rays.Results Twenty-six patients underwent single level Bryan disc arthroplasty and twenty-four patients underwent single level anterior cervical decompression and fusion.All patients were followed up for an average of sixty months.In the Bryan arthroplasty group,nine(17.6%)segments developed adjacent segment degeneration,which was significantly lower than that(60.4%)in the anterior cervical decompression and fusion group.Eleven segments in the Bryan arthroplasty group developed heterotopic ossification according to McAfee's classification and two segments had range of motion less than 2°.In the heterotopic ossification group,four(19.5%)segments developed adjacent segment degeneration,similar to the number in the non-heterotopic ossification group(16.7%).Adjacent segment degeneration rate was 50% in gradeⅣ?group but 11.8% in gradeⅡ?to Ⅲ.Conclusions Adjacent segment degeneration was accelerated after anterior cervical decompression and fusion.However,Bryan disc arthroplasty avoided accelerated adjacent segment degeneration by preserving motion.Patients with gradeⅣ?heterotopic ossification lost motion,and the rate of adjacent segment degeneration was higher than that in patients without heterotopic ossification.

  10. Disc degeneration: current surgical options

    C Schizas


    Full Text Available Chronic low back pain attributed to lumbar disc degeneration poses a serious challenge to physicians. Surgery may be indicated in selected cases following failure of appropriate conservative treatment. For decades, the only surgical option has been spinal fusion, but its results have been inconsistent. Some prospective trials show superiority over usual conservative measures while others fail to demonstrate its advantages. In an effort to improve results of fusion and to decrease the incidence of adjacent segment degeneration, total disc replacement techniques have been introduced and studied extensively. Short-term results have shown superiority over some fusion techniques. Mid-term results however tend to show that this approach yields results equivalent to those of spinal fusion. Nucleus replacement has gained some popularity initially, but evidence on its efficacy is scarce. Dynamic stabilisation, a technique involving less rigid implants than in spinal fusion and performed without the need for bone grafting, represents another surgical option. Evidence again is lacking on its superiority over other surgical strategies and conservative measures. Insertion of interspinous devices posteriorly, aiming at redistributing loads and relieving pain, has been used as an adjunct to disc removal surgery for disc herniation. To date however, there is no clear evidence on their efficacy. Minimally invasive intradiscal thermocoagulation techniques have also been tried, but evidence of their effectiveness is questioned. Surgery using novel biological solutions may be the future of discogenic pain treatment. Collaboration between clinicians and basic scientists in this multidisciplinary field will undoubtedly shape the future of treating symptomatic disc degeneration.

  11. The Danish Shoulder Arthroplasty Registry

    Rasmussen, Jeppe; Jakobsen, John; Brorson, Stig


    The Danish Shoulder Arthroplasty Registry (DSR) was established in 2004. Data are reported electronically by the surgeons. Patient-reported outcome is collected 10-14 months postoperatively using the Western Ontario osteoarthritis of the shoulder index (WOOS). 2,137 primary shoulder arthroplastie...

  12. Modeling and Thermal Analysis of Disc

    Brake Praveena S


    Full Text Available The disc brake is a device used for slowing or stopping the rotation of the vehicle. Number of times using the brake for vehicle leads to heat generation during braking event, such that disc brake undergoes breakage due to high Temperature. Disc brake model is done by CATIA and analysis is done by using ANSYS workbench. The main purpose of this project is to study the Thermal analysis of the Materials for the Aluminum, Grey Cast Iron, HSS M42, and HSS M2. A comparison between the four materials for the Thermal values and material properties obtained from the Thermal analysis low thermal gradient material is preferred. Hence best suitable design, low thermal gradient material Grey cast iron is preferred for the Disc Brakes for better performance.

  13. Eclipse Mapping: Astrotomography of Accretion Discs

    Baptista, Raymundo


    The Eclipse Mapping Method is an indirect imaging technique that transforms the shape of the eclipse light curve into a map of the surface brightness distribution of the occulted regions. Three decades of application of this technique to the investigation of the structure, the spectrum and the time evolution of accretion discs around white dwarfs in cataclysmic variables have enriched our understanding of these accretion devices with a wealth of details such as (but not limited to) moving heating/cooling waves during outbursts in dwarf novae, tidally-induced spiral shocks of emitting gas with sub-Keplerian velocities, elliptical precessing discs associated to superhumps, and measurements of the radial run of the disc viscosity through the mapping of the disc flickering sources. This chapter reviews the principles of the method, discusses its performance, limitations, useful error propagation procedures, as well as highlights a selection of applications aimed at showing the possible scientific problems that ha...

  14. Laser Discs, Barcodes, and Books--a Great Combination.

    Peto, Erica


    Describes the use of barcodes to link laser discs with books in school libraries. Highlights include use of a barcode reader as a remote control device as well as a scanner, guidelines for making laser disc books, and a sidebar that explains how to make barcodes and describes software. (LRW)

  15. Black hole accretion discs

    Lasota, Jean-Pierre


    This is an introduction to models of accretion discs around black holes. After a presentation of the non-relativistic equations describing the structure and evolution of geometrically thin accretion discs we discuss their steady-state solutions and compare them to observation. Next we describe in detail the thermal-viscous disc instability model and its application to dwarf novae for which it was designed and its X-ray irradiated-disc version which explains the soft X--ray transients, i.e. outbursting black-hole low-mass X-ray binaries. We then turn to the role of advection in accretion flow onto black holes illustrating its action and importance with a toy model describing both ADAFs and slim discs. We conclude with a presentation of the general-relativistic formalism describing accretion discs in the Kerr space-time.

  16. MHD disc winds

    Ferreira, J


    This is a doctorate level lecture on the physics of accretion discs driving magnetically self-confined jets, usually referred to in the literature as disc winds. I will first review the governing magnetohydrodynamic equations and then discuss their physical content. At that level, necessary conditions to drive jets from keplerian accretion discs can already be derived. These conditions are validated with self-similar calculations of accretion-ejection structures. In a second part, I will critically discuss the biases introduced when using self-similarity as well as some other questions such as: Are these systems really unstable? Can a standard accretion disc provide the conditions to launch jets in its innermost parts? What is the difference between X-winds and disc-winds? Finally, the magnetic interaction between a protostar and its circumstellar disc will be discussed with a focus on stellar spin down.

  17. Black hole accretion discs

    Lasota, Jean-Pierre


    This is an introduction to models of accretion discs around black holes. After a presentation of the non-relativistic equations describing the structure and evolution of geometrically thin accretion discs we discuss their steady-state solutions and compare them to observation. Next we describe in detail the thermal-viscous disc instability model and its application to dwarf novae for which it was designed and its X-ray irradiated-disc version which explains the soft X--ray transients, i.e. ou...

  18. Mortality after shoulder arthroplasty

    Amundsen, Alexander; Rasmussen, Jeppe Vejlgaard; Olsen, Bo Sanderhoff


    BACKGROUND: The primary aim was to quantify the 30-day, 90-day, and 1-year mortality rates after primary shoulder replacement. The secondary aims were to assess the association between mortality and diagnoses and to compare the mortality rate with that of the general population. METHODS: The study...... included 5853 primary operations reported to the Danish Shoulder Arthroplasty Registry between 2006 and 2012. Information about deaths was obtained from the Danish Cause of Death Register and the Danish Civil Registration System. Age- and sex-adjusted control groups were retrieved from Statistics Denmark...

  19. Crova's Disc: A Way to Make Sound Waves "Visible."

    Hastings, R. B.


    Explained are the differences between and offered are examples of longitudinal and transverse sound waves. Described is the construction of the Crova's Disc, a device used in the teaching of the propagation and properties of sound waves. (DS)


    Sporer, Scott M.; Bernard R. Bach, Jr


    DESCRIPTION A user friendly reference for decision making in hip arthroplasty designed in a question formed clinical problem scenarios and answers format .The articles composed of the answers, containing current concepts and preferences of experts in primary and revision hip surgery are enhanced by several images, diagrams and references and written in the form of a curbside consultation by Scott M. Sporer, MD. and his collaborators. PURPOSE By this practical reference of hip arthroplasty, Sc...

  1. Stemless shoulder arthroplasty: current status.

    Churchill, R Sean


    Since the original Neer humeral replacement in the 1950s, the standard primary anatomic total shoulder arthroplasty design has slowly evolved. Most recently, the humeral stem has become progressively shorter to help combat stem-related complications. Currently, there are several companies who have developed and marketed a stemless humeral arthroplasty component. Manufacturers' data for 5 stemless shoulder arthroplasty components currently on the market were analyzed and reviewed. A literature review of short-term results for stemless shoulder arthroplasty was completed. Of the stemless shoulder arthroplasty systems available on the market, 3 are currently undergoing clinical trials in the United States. The Tornier Simpliciti (Tornier, Edina, MN, USA) clinical trial began in 2011. The study with 2-year minimum follow-up results is scheduled for completion in November 2014. The Arthrex Eclipse (Arthrex, Naples, FL, USA) clinical trial was started in January 2013. The tentative study completion date is 2017. The Biomet Nano (Biomet, Warsaw, IN, USA) clinical trial began in October 2013 and also has a tentative completion date of 2017. No other clinical trial is currently under way in the United States. Early results for stemless shoulder arthroplasty indicate clinical results similar to standard stemmed shoulder arthroplasty. Radiographic analysis indicates implant stability without migration or subsidence at 2- to 3-year minimum follow-up.. Several stemless shoulder arthroplasty implants are available outside the United States. Early clinical and radiographic results are promising, but well-designed clinical studies and midterm results are lacking. Three clinical trials are currently under way in the United States with initial availability for use anticipated in 2015. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

  2. New in vivo animal model to create intervertebral disc degeneration and to investigate the effects of therapeutic strategies to stimulate disc regeneration.

    Kroeber, Markus W; Unglaub, Frank; Wang, Haili; Schmid, Carsten; Thomsen, Marc; Nerlich, Andreas; Richter, Wiltrud


    A new rabbit model was developed that produces disc degeneration through the application of controlled and quantified axial mechanical load. To characterize the changes associated with disc degeneration, and to evaluate the feasibility of local transfer of agents to the compressed discs to stimulate disc regeneration. Studies have shown that accelerated degeneration of the intervertebral disc results from altered mechanical loading conditions. The development of methods for the prevention of disc degeneration and the restoration of disc tissue that has already degenerated is needed. New Zealand white rabbits (n = 33) were used for this study. The discs in five animals remained unloaded and served as controls, whereas in 28 animals the discs were axially compressed using a custom-made external loading device. After 1 (n = 7), 14 (n = 7), and 28 (n = 7) days of dynamic loading, or 28 (n = 7) days of loading followed by 28 days of unloaded recovery time, the animals were killed and the lumbar spine was harvested for tissue preparation. Disc height, disc morphology, cell viability, disc stiffness, and load to failure were measured. Recombinant adenovirus encoding for two different marker genes (Ad-Luciferase and Ad-LacZ) was injected into the discs in loaded specimens and the gene expression was measured. The unloaded intervertebral discs of the rabbits consisted of a layered anulus fibrosus, a cartilaginous endplate, and a nucleus pulposus comparable with those of humans. After 14 and 28 days of loading, the discs demonstrated a significant decrease in disc space. Histologically, disorganization of the architecture of the anulus occurred. The number of dead cells increased significantly in the anulus and cartilage endplate. These changes were not reversible after 28 days of unloading. The stiffness and the load to failure did not change significantly in the discs after 28 days of loading, as compared with the unloaded control discs. Adenovirus-mediated gene transfer

  3. Optic disc oedema

    Nielsen, Marianne Kromann; Hamann, Steffen


    Optic disc oedema describes the nonspecific, localized swelling of the optic nerve head regardless of aetiology. Therefore, differentiating among the various aetiologies depends on a thorough history and knowledge of the clinical characteristics of the underlying conditions. Papilloedema strictly...... refers to optic disc oedema as a consequence of elevated intracranial pressure. It is usually a bilateral condition and visual function is preserved until late. Optic disc oedema caused by an anterior optic neuropathy is usually unilateral and accompanied by the loss of visual function....

  4. Artificial Disc Replacement

    ... Strengthening Strengthen Your Core! Stretching/Flexibility Aerobic Exercise Cervical ... disc is the soft cushioning structure located between the individual bones of the spine, called “vertebra.” It is made of cartilage-like tissue and ...

  5. A rolling-gliding wear simulator for the investigation of tribological material pairings for application in total knee arthroplasty

    Denkena Berend


    Full Text Available Abstract Background Material wear testing is an important technique in the development and evaluation of materials for use in implant for total knee arthroplasty. Since a knee joint induces a complex rolling-gliding movement, standardised material wear testing devices such as Pin-on-Disc or Ring-on-Disc testers are suitable to only a limited extent because they generate pure gliding motion only. Methods A rolling-gliding wear simulator was thus designed, constructed and implemented, which simulates and reproduces the rolling-gliding movement and loading of the knee joint on specimens of simplified geometry. The technical concept was to run a base-plate, representing the tibia plateau, against a pivoted cylindrical counter-body, representing one femur condyle under an axial load. A rolling movement occurs as a result of the friction and pure gliding is induced by limiting the rotation of the cylindrical counter-body. The set up also enables simplified specimens handling and removal for gravimetrical wear measurements. Long-term wear tests and gravimetrical wear measurements were carried out on the well known material pairings: cobalt chrome-polyethylene, ceramic-polyethylene and ceramic-ceramic, over three million motion cycles to allow material comparisons to be made. Results The observed differences in wear rates between cobalt-chrome on polyethylene and ceramic on polyethylene pairings were similar to the differences of published data for existing material-pairings. Test results on ceramic-ceramic pairings of different frontal-plane geometry and surface roughness displayed low wear rates and no fracture failures. Conclusions The presented set up is able to simulate the rolling-gliding movement of the knee joint, is easy to use, and requires a minimum of user intervention or monitoring. It is suitable for long-term testing, and therefore a useful tool for the investigation of new and promising materials which are of interest for application in

  6. Cervical arthroplasty: a critical review of the literature.

    Alvin, Matthew D; Abbott, E Emily; Lubelski, Daniel; Kuhns, Benjamin; Nowacki, Amy S; Steinmetz, Michael P; Benzel, Edward C; Mroz, Thomas E


    Cervical disc arthroplasty (CDA) is a motion-preserving procedure that is an alternative to fusion. Proponents of arthroplasty assert that it will maintain cervical motion and prevent or reduce adjacent segment degeneration. Accordingly, CDA, compared with fusion, would have the potential to improve clinical outcomes. Published studies have varying conclusions on whether CDA reduces complications and/or improves outcomes. As many of these previous studies have been funded by CDA manufacturers, we wanted to ascertain whether there was a greater likelihood for these studies to report positive results. To critically assess the available literature on cervical arthroplasty with a focus on the time of publication and conflict of interest (COI). Review of the literature. All clinical articles about CDA published in English through August 1, 2013 were identified on Medline. Any article that presented CDA clinical results was included. Study design, sample size, type of disc, length of follow-up, use of statistical analysis, quality-of-life (QOL) outcome scores, COI, and complications were recorded. A meta-analysis was conducted stratifying studies by COI and publication date to identify differences in complication rates reported. Seventy-four studies were included that investigated 8 types of disc prosthesis and 22 met the criteria for a randomized controlled trial (RCT). All Level Ib RCTs reported superior quality-of-life outcomes for CDA versus anterior cervical discectomy and fusion (ACDF) at 24 months. Fifty of the 74 articles (68%) had a disclosure section, including all Level Ib RCTs, which had significant COIs related to the respective studies. Those studies without a COI reported mean weighted average adjacent segment disease rates of 6.3% with CDA and 6.2% with ACDF. In contrast, the reverse was reported by studies with a COI, for which the averages were 2.5% with CDA and 6.3% with ACDF. Those studies with a COI (n=31) had an overall weighted average heterotopic

  7. 圆盘式甜菜收获机自动导向装置的参数优化与试验%Parameter optimization and test on auto guide device for disc type sugar beet harvester

    王方艳; 张东兴


    为了提高圆盘式甜菜收获机的对行收获质量,该文结合导向装置的结构及工作特点,分析了导向机构的受载及运动特性,得到了导向机构在运动过程中的加速度方程,并确定了影响导向对行效果的关键参数。采用响应面优化设计方法,建立了关键参数与导向损失率之间的数学模型,确定了较优的参数组合(弯角为145°,安装角为8°,水平长度为240 mm)。田间试验表明:导向装置可实现甜菜收获机的自动导向对行收获,收获损失率为5.12%,且满足甜菜收获机收获质量的行业标准(NY/T 1412-2007)。研究结果可为同类甜菜收获机的研发和单株块根作物的导向对行收获研究提供参考。%Sugar beet is one of the most important sugar crops in China, which ranked second in terms of acreage, only after sugarcane. As a kind of seasonal operation, sugar beet harvesting in China is still mainly manual work, which constrains the further development of the sugar beet industry. Mechanized combine harvesting is the inevitable development trend of sugar beet harvesting. Guidance system is the major part of harvest machine, which can reduce the driver’s labor intensity and beet’s harvest damage in the harvest process. With the development of the technology of electronics, sensor and GPS guidance, the guide technology has been commercialized and applied to the field of agricultural equipment widely in the developed countries. The combine harvesting with the guide device is characterized by high automation and intelligence and advanced performance. However, the guide device is still in the stage of prototype development in China, and there is a great gap between domestic and advanced foreign technology. The research on beet’s guiding harvest is scarce, and this restricts the quality of beet digging and mechanization. To solve the problem of the guide on-row harvest of disc type sugar beet harvester, the

  8. Transfemoral amputation after failed knee arthroplasty

    Gottfriedsen, Tinne B; Morville Schrøder, Henrik; Odgaard, Anders


    BACKGROUND: Transfemoral amputation is considered the last treatment option for failed knee arthroplasty. The extent to which this procedure is performed is not well known. The purpose of this study was to identify the incidence and causes of amputation following failure of knee arthroplasty...... in a nationwide population. METHODS: Data were extracted from the Danish Civil Registration System, the Danish National Patient Register, and the Danish Knee Arthroplasty Register. With use of individual data linkage, 92,785 primary knee arthroplasties performed from 1997 to 2013 were identified. Of these, 258...... for causes related to failed knee arthroplasty. The 15-year cumulative incidence of amputation was 0.32% (95% confidence interval [CI], 0.23% to 0.48%). The annual incidence of amputation following arthroplasties performed from 1997 to 2002 was 0.025% compared with 0.018% following arthroplasties performed...

  9. Optimization of Valve Disc Using Orthogonal Array and Kriging Model

    Song, Xueguan; Wang, Lin; Kang, Jungho; Kim, Seung Gyu; Jo, Young Jik; Park, Youngchul


    A butterfly valve is a type of flow control device, typically used to regulate a fluid flowing. Currently, FEA is often used to predict the safety in the design of valve disc. Also, the study about the affection of butterfly valve's disc to the valve flow characteristics by using CFD has been done by many researchers. Along with the development of computer technique, design and analysis of computer experiments has becoming more and more important in engineering design and optimization. Hereinto Kriging model is one popular analysis approach for the purpose of creating a cheap "meta-model" as a surrogate to a computationally expensive simulation model. In this paper, the numerical analysis considered the strength, pressure loss coefficient and weight of valve disc simultaneously is investigated to improve the shape of a traditional butterfly valve disc. Firstly, an initial model of butterfly valve is made to evaluate the performance of the valve disc by using CFD and FEM. Then several experiments with different variables combination of the valve disc are conducted by mean of orthogonal array. Finally, the Kriging model is used to find the optimum variables combination of valve disc based on the result of computer experiments. In addition, the optimum result is verified by FEA and CFD simulation again. The result shows that compared with traditional computer experiments, optimization by using Kriging model can improve the weight of the valve disc very effectively in a short time.

  10. Microendoscopic discectomy for treatment of lumbar disc herniation

    ARJUN Sinkemani; WU Xiao-tao


    A lumbar microendoscopic discectomy ( MED ) is a minimally invasive surgical technique performed through a tubular device which is designed for the pain relieve caused by herniated discs pressing the nerve roots . In 1997, a new minimally invasive surgical approach for the management of symptomatic lumbar disc herniation , MED was introduced .This technique uses a tubular retractor system and a microendoscope for visualization rather than the operating microscope .However , recent literature suggests that MED is an effective microendoscopic system which has a fine long-term outcome in treating lumbar disc herniation .This article describes the operative tech-niques and outcomes reported in the literature for MED .

  11. Innervation of ''painful'' lumbar discs

    Coppes, MH; Marani, E; Thomeer, RTWM; Groen, GJ


    Study Design. The authors investigated the innervation of discographically confirmed degenerated and ''painful'' human intervertebral discs. Objective. To determine the type and distribution patterns of nerve fibers present in degenerated human intervertebral discs. Summary of Background Data. The i

  12. How do accretion discs break?

    Dogan, Suzan


    Accretion discs are common in binary systems, and they are often found to be misaligned with respect to the binary orbit. The gravitational torque from a companion induces nodal precession in misaligned disc orbits. In this study, we first calculate whether this precession is strong enough to overcome the internal disc torques communicating angular momentum. We compare the disc precession torque with the disc viscous torque to determine whether the disc should warp or break. For typical parameters precession wins: the disc breaks into distinct planes that precess effectively independently. To check our analytical findings, we perform 3D hydrodynamical numerical simulations using the PHANTOM smoothed particle hydrodynamics code, and confirm that disc breaking is widespread and enhances accretion on to the central object. For some inclinations, the disc goes through strong Kozai cycles. Disc breaking promotes markedly enhanced and variable accretion and potentially produces high-energy particles or radiation through shocks. This would have significant implications for all binary systems: e.g. accretion outbursts in X-ray binaries and fuelling supermassive black hole (SMBH) binaries. The behaviour we have discussed in this work is relevant to a variety of astrophysical systems, for example X-ray binaries, where the disc plane may be tilted by radiation warping, SMBH binaries, where accretion of misaligned gas can create effectively random inclinations and protostellar binaries, where a disc may be misaligned by a variety of effects such as binary capture/exchange, accretion after binary formation.

  13. Eclipse Mapping: Astrotomography of Accretion Discs

    Baptista, Raymundo

    The Eclipse Mapping Method is an indirect imaging technique that transforms the shape of the eclipse light curve into a map of the surface brightness distribution of the occulted regions. Three decades of application of this technique to the investigation of the structure, the spectrum and the time evolution of accretion discs around white dwarfs in cataclysmic variables have enriched our understanding of these accretion devices with a wealth of details such as (but not limited to) moving heating/cooling waves during outbursts in dwarf novae, tidally-induced spiral shocks of emitting gas with sub-Keplerian velocities, elliptical precessing discs associated to superhumps, and measurements of the radial run of the disc viscosity through the mapping of the disc flickering sources. This chapter reviews the principles of the method, discusses its performance, limitations, useful error propagation procedures, as well as highlights a selection of applications aimed at showing the possible scientific problems that have been and may be addresses with it.

  14. Tracing Planets in Circumstellar Discs

    Uribe Ana L.


    Full Text Available Planets are assumed to form in circumstellar discs around young stellar objects. The additional gravitational potential of a planet perturbs the disc and leads to characteristic structures, i.e. spiral waves and gaps, in the disc density profile. We perform a large-scale parameter study on the observability of these planet-induced structures in circumstellar discs in the (submm wavelength range for the Atacama Large (SubMillimeter Array (ALMA. On the basis of hydrodynamical and magneto-hydrodynamical simulations of star-disc-planet models we calculate the disc temperature structure and (submm images of these systems. These are used to derive simulated ALMA maps. Because appropriate objects are frequent in the Taurus-Auriga region, we focus on a distance of 140 pc and a declination of ≈ 20°. The explored range of star-disc-planet configurations consists of six hydrodynamical simulations (including magnetic fields and different planet masses, nine disc sizes with outer radii ranging from 9 AU to 225 AU, 15 total disc masses in the range between 2.67·10-7 M⊙ and 4.10·10-2 M⊙, six different central stars and two different grain size distributions, resulting in 10 000 disc models. At almost all scales and in particular down to a scale of a few AU, ALMA is able to trace disc structures induced by planet-disc interaction or the influence of magnetic fields in the wavelength range between 0.4...2.0 mm. In most cases, the optimum angular resolution is limited by the sensitivity of ALMA. However, within the range of typical masses of protoplane tary discs (0.1 M⊙...0.001 M⊙ the disc mass has a minor impact on the observability. At the distance of 140 pc it is possible to resolve discs down to 2.67·10-6 M⊙ and trace gaps in discs with 2.67·10-4 M⊙ with a signal-to-noise ratio greater than three. In general, it is more likely to trace planet-induced gaps in magneto-hydrodynamical disc models, because gaps are wider in the presence of

  15. Rare complications of osteolysis and periprosthetic tissue reactions after hybrid and non-hybrid total disc replacement.

    Veruva, Sai Y; Lanman, Todd H; Hanzlik, Josa A; Kurtz, Steven M; Steinbeck, Marla J


    Few complications have been reported for lumbar total disc replacement (TDR) and hybrid TDR fixations. This study evaluated retrieved implants and periprosthetic tissue reactions for two cases of osteolysis following disc arthroplasty with ProDisc-L prostheses. Implants were examined for wear and surface damage, and tissues for inflammation, polyethylene wear debris (polarized light microscopy) and metal debris (energy-dispersive X-ray spectroscopy). Despite initial good surgical outcomes, osteolytic cysts were noted in both patients at vertebrae adjacent to the implants. For the hybrid TDR case, heterotopic ossification and tissue necrosis due to wear-induced inflammation were observed. In contrast, the non-hybrid implant showed signs of abrasion and impingement, and inflammation was observed in tissue regions with metal and polyethylene wear debris. In both cases, wear debris and inflammation may have contributed to osteolysis. Surgeons using ProDisc prostheses should be aware of these rare complications.

  16. Evolution of Protoplanetary Discs with Magnetically Driven Disc Winds

    Suzuki, Takeru K; Morbidelli, Alessandro; Crida, Aurélien; Guillot, Tristan


    Aims: We investigate the evolution of protoplanetary discs (PPDs hereafter) with magnetically driven disc winds and viscous heating. Methods: We consider an initially massive disc with ~0.1 Msun to track the evolution from the early stage of PPDs. We solve the time evolution of surface density and temperature by taking into account viscous heating and the loss of the mass and the angular momentum by the disc winds within the framework of a standard alpha model for accretion discs. Our model parameters, turbulent viscosity, disc wind mass loss, and disc wind torque, which are adopted from local magnetohydrodynamical simulations and constrained by the global energetics of the gravitational accretion, largely depends on the physical condition of PPDs, particularly on the evolution of the vertical magnetic flux in weakly ionized PPDs. Results: Although there are still uncertainties concerning the evolution of the vertical magnetic flux remaining, surface densities show a large variety, depending on the combinatio...

  17. Counter-Rotating Accretion Discs

    Dyda, Sergei; Lovelace, Richard V. E.; Ustyugova, Galina V.; Romanova, Marina M.; Koldoba, Alexander V.


    Counter-rotating discs can arise from the accretion of a counter-rotating gas cloud onto the surface of an existing co-rotating disc or from the counter-rotating gas moving radially inward to the outer edge of an existing disc. At the interface, the two components mix to produce gas or plasma with zero net angular momentum which tends to free-fall towards the disc center. We discuss high-resolution axisymmetric hydrodynamic simulations of a viscous counter-rotating disc for cases where the tw...

  18. Cervicothoracic junction arthroplasty after previous fusion surgery for adjacent segment degeneration: case report.

    Sekhon, Lali


    This is the first reported case of cervical arthroplasty using the Bryan Cervical Disc Prosthesis System (Medtronic Sofamor Danek, Inc., Memphis, TN) in the management of adjacent segment degeneration associated with previous fusion surgery and surgery at the cervicothoracic junction. This case report describes a 25-year-old woman who initially underwent a two-level anterior cervical fusion in 1998, 2 years after being involved in a motor vehicle accident. She was well until 18 months before presentation, when she developed bilateral shoulder pain, mechanical neck pain worse on flexion, and bilateral C8 distribution arm pain and paresthesia. On clinical examination, no focal deficits were found, although the range of motion was reduced. Preoperative cervical spine x-rays and magnetic resonance scanning confirmed accelerated degeneration of the C4-C5 and C7-T1 disc spaces, with evidence of neural compression at those levels. After careful consideration of various treatment options and failure of all conservative measures, the patient underwent an anterior C4-C5 and C7-T1 decompression with removal of the anterior cervical plate and placement of two artificial disc prostheses. After surgery, her course was uncomplicated and she was discharged from hospital well. There was complete resolution of the arm symptoms and reduction of the neck pain, with a reduction in the amount of analgesia she was taking. Seven months after surgery, she remains well with repeat x-rays confirming motion at the operated levels. This case demonstrates that cervical arthroplasty is a reasonable treatment option for patients who have had previous surgery in which interbody fusion has been performed and who have developed degeneration of adjacent levels. Despite the altered biomechanics at the cervicothoracic junction, no adverse features were noted with arthroplasty at this level.

  19. Vibration analysis of atomising discs

    Deng, H; Ouyang, H, E-mail: [Department of Engineering, University of Liverpool, Liverpool L69 3GH (United Kingdom)


    The centrifugal atomisation of metallic melts using a spinning disc is an important process for powder production and spray deposition. In the manufacturing process the high-temperature melt flows down to the surface of the atomising disc spinning at very high speed. It is observed that there is a hydraulic jump of the melt flow prior to atomisation. In this paper, the dynamic model of the atomising disc as a spinning Kirchhoff plate with this hydraulic jump is established. The flowing melt is modelled as moving mass and weight force in the radial direction. Using a Galerkin method, it is found that the vibration properties of the atomising disc vary with the disc clamping ratio. The amplitude of the vibration is largely raised when the clamping ratio is smaller than the critical jump radius ratio. It is also found that the disc vibration is non-stationary before becoming steady and the amplitude decreases with increasing disc speed.

  20. Discs in misaligned binary systems

    Rawiraswattana, Krisada; Goodwin, Simon P


    We perform SPH simulations to study precession and changes in alignment between the circumprimary disc and the binary orbit in misaligned binary systems. We find that the precession process can be described by the rigid-disc approximation, where the disc is considered as a rigid body interacting with the binary companion only gravitationally. Precession also causes change in alignment between the rotational axis of the disc and the spin axis of the primary star. This type of alignment is of great important for explaining the origin of spin-orbit misaligned planetary systems. However, we find that the rigid-disc approximation fails to describe changes in alignment between the disc and the binary orbit. This is because the alignment process is a consequence of interactions that involve the fluidity of the disc, such as the tidal interaction and the encounter interaction. Furthermore, simulation results show that there are not only alignment processes, which bring the components towards alignment, but also anti-...


    Scott M. Sporer


    Full Text Available DESCRIPTION A user friendly reference for decision making in hip arthroplasty designed in a question formed clinical problem scenarios and answers format .The articles composed of the answers, containing current concepts and preferences of experts in primary and revision hip surgery are enhanced by several images, diagrams and references and written in the form of a curbside consultation by Scott M. Sporer, MD. and his collaborators. PURPOSE By this practical reference of hip arthroplasty, Scott M. Sporer, MD. and the contributors have aimed providing the reader practical and clinically relevant information, evidence-based advices, their preferences and opinions containing current concepts for difficult and controversial clinical situations in total hip replacement surgery which are often not addressed clearly in traditional references. FEATURES The book is composed of 9 sections and 49 articles each written by a different expert designed in a question and answers format including several images and diagrams and also essential references at the end of each article. In the first section preoperative questions is subjected. Second section is about preoperative acetabulum questions. Third section is about preoperative femur questions. Fourth section is about intraoperative questions. Intraoperative acetabulum question is subjected in the fifth section and the intraoperative femur questions in the sixth section. The seventh section is about postoperative questions. Eighth and ninth sections are about general questions about failure and failure of acetabulum in turn. AUDIENCE Mainly practicing orthopedic surgeons, fellows and residents who are interested in hip arthroplasty have been targeted but several carefully designed scenarios of controversial and difficult situations surrounding total hip replacement surgery and the current information will also be welcomed by experienced clinicians practicing in hip arthroplasty. ASSESSMENT Scott M. Sporer

  2. Human and bovine spinal disc mechanics subsequent to trypsin injection

    Jeremy Alsup


    The Translational Potential of this Article: Preclinical testing of novel spinal devices is essential to the design validation and regulatory processes, but current testing techniques rely on cadaveric testing of primarily older spines with essentially random amounts of disc degeneration. The present work investigates the viability of using trypsin injections to create a more uniform preclinical model of disc degeneration from a mechanics perspective, for the purpose of testing spinal devices. Such a model would facilitate translation of new spinal technologies to clinical practice.

  3. Semiconductor-based, large-area, flexible, electronic devices

    Goyal, Amit


    Novel articles and methods to fabricate the same resulting in flexible, large-area, triaxially textured, single-crystal or single-crystal-like, semiconductor-based, electronic devices are disclosed. Potential applications of resulting articles are in areas of photovoltaic devices, flat-panel displays, thermophotovoltaic devices, ferroelectric devices, light emitting diode devices, computer hard disc drive devices, magnetoresistance based devices, photoluminescence based devices, non-volatile memory devices, dielectric devices, thermoelectric devices and quantum dot laser devices.

  4. Accretion Discs in Blazars

    Jolley, E. J. D.; Kuncic, Z.; Bicknell, G. V.; Wagner, S.(Max-Planck-Institut für Kernphysik, 69117, Heidelberg, Germany)


    The characteristic properties of blazars (rapid variability, strong polarization, high brightness) are widely attributed to a powerful relativistic jet oriented close to our line of sight. Despite the spectral energy distributions (SEDs) being strongly jet-dominated, a "big blue bump" has been recently detected in sources known as flat spectrum radio quasars (FSRQs). These new data provide a unique opportunity to observationally test coupled jet-disc accretion models in these extreme sources....

  5. Factors Affecting the Oxygenation Capacity of Disc Aerators in an Oxidation Ditch System

    Abdel E. Ghaly


    Full Text Available Problem statement: The use of aerobic biological methods for the treatment of livestock wastes has resulted in a proliferation of mechanical aeration devices to accomplish the desired treatment. The oxidation ditch system with disc aerators is among the aerobic systems that have been used to treat livestock waste. The main objectives of this study were to investigate the effects of various disc design parameters and system operational parameters on the oxygen transfer coefficient and to study the physical phenomenon of oxygen transfer using high speed movie techniques. Approach: A bench-scale oxidation ditch with a disc aerator was used to conduct a series of experiments to determine the effects of immersion depth (2.5-7.5 cm, disc speed (50-250 rpm, disc thickness (0.32-2.55 cm, hole diameter (0.00-1.92 cm and number of rotating discs (1-2 on the oxygen transfer coefficient. The unsteady state method with sodium sulfite oxidation was used to deoxygenate the water and the dissolved oxygen concentration was measured with time. Results: The disc speed had the most significant effect on KLa with the immersion depth and hole diameter both showing strong effects and the disc thickness showing less effect. The effect of adding a second disc was comparable to using a single disc of double the thickness at lower speeds while at speeds higher than 200 rpm doubling the thickness of a single disc had less effect than a second disc. Conclusion: The highest oxygen transfer (1.526 min-1 was achieved using two coaxial discs with a disc speed of 250 rpm, a disc thickness of 0.64 cm, a hole diameter of 1.92 cm and an immersion depth of 7.5 cm. Bubble aeration and eddy aeration were the most prevalent mechanisms of oxygen transfer in the oxidation ditch while surface aeration played a relatively small role in oxygen transfer.

  6. [Uncemented arthroplasty of the hip].

    von Schulze Pellengahr, C; Fottner, A; Utzschneider, S; Schmitt-Sody, M; Teske, W; Lichtinger, T; Esenwein, S A


    Prognosis of cemented total hip replacement seems to be excellent for elderly patients. In younger age the outcome is less favourable and early revision is more common. Thus, different concepts with better prognosis and preservation of bone stock for possible revisions were needed. After more than 30 years of application with excellent short-term and long-term results, uncemented total hip arthroplasty is nowadays generally regarded as the standard procedure for younger patients. New bone-preserving implants, such as surface replacement or short-stemmed femoral shaft prostheses, have been introduced especially for younger patients. Some of these new procedures are still under development, and the long-term results of new implant concepts have to be evaluated over the next decades. Regarding recently published scientific studies an overview about non-cemented total hip arthroplasty is given and current concepts and developments are presented.

  7. Total disc replacement.

    Vital, J-M; Boissière, L


    Total disc replacement (TDR) (partial disc replacement will not be described) has been used in the lumbar spine since the 1980s, and more recently in the cervical spine. Although the biomechanical concepts are the same and both are inserted through an anterior approach, lumbar TDR is conventionally indicated for chronic low back pain, whereas cervical TDR is used for soft discal hernia resulting in cervicobrachial neuralgia. The insertion technique must be rigorous, with precise centering in the disc space, taking account of vascular anatomy, which is more complex in the lumbar region, particularly proximally to L5-S1. All of the numerous studies, including prospective randomized comparative trials, have demonstrated non-inferiority to fusion, or even short-term superiority regarding speed of improvement. The main implant-related complication is bridging heterotopic ossification with resulting loss of range of motion and increased rates of adjacent segment degeneration, although with an incidence lower than after arthrodesis. A sufficiently long follow-up, which has not yet been reached, will be necessary to establish definitively an advantage for TDR, particularly in the cervical spine. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  8. Apsidal precession, disc breaking and viscosity in warped discs

    Nealon, Rebecca; Price, Daniel J; King, Andrew


    We demonstrate the importance of general relativistic apsidal precession in warped black hole accretion discs by comparing three - dimensional smoothed particle hydrodynamic simulations in which this effect is first neglected, and then included. If apsidal precession is neglected, we confirm the results of an earlier magnetohydrodynamic simulation which made this assumption, showing that at least in this case the $\\alpha$ viscosity model produces very similar results to those of simulations where angular momentum transport is due to the magnetorotational instability. Including apsidal precession significantly changes the predicted disc evolution. For moderately inclined discs thick enough that tilt is transported by bending waves, we find a disc tilt which is nonzero at the inner disc edge and oscillates with radius, consistent with published analytic results. For larger inclinations we find disc breaking.

  9. Mechanics of Actuated Disc Cutting

    Dehkhoda, Sevda; Detournay, Emmanuel


    This paper investigates the mechanics of an actuated disc cutter with the objective of determining the average forces acting on the disc as a function of the parameters characterizing its motion. The specific problem considered is that of a disc cutter revolving off-centrically at constant angular velocity around a secondary axis rigidly attached to a cartridge, which is moving at constant velocity and undercutting rock at a constant depth. This model represents an idealization of a technology that has been implemented in a number of hard rock mechanical excavators with the goal of reducing the average thrust force to be provided by the excavation equipment. By assuming perfect conformance of the rock with the actuated disc as well as a prescribed motion of the disc (perfectly rigid machine), the evolution of the contact surface between the disc and the rock during one actuation of the disc can be computed. Coupled with simple cutter/rock interaction models that embody either a ductile or a brittle mode of fragmentation, these kinematical considerations lead to an estimate of the average force on the cartridge and of the partitioning of the energy imparted by the disc to the rock between the actuation mechanism of the disc and the translation of the cartridge on which the actuated disc is attached.

  10. Estrogens and the intervertebral disc.

    Calleja-Agius, J; Muscat-Baron, Y; Brincat, M P


    Intervertebral discs are an integral part of the vertebral column. It has been shown that menopause has a negative effect on bone and on intervertebral discs. Estrogen has a beneficial effect of preserving the health of collagen-containing tissues, including the intervertebral disc. The intervertebral disc allows for mobility of the spine, and maintains a uniform stress distribution of the area of the vertebral endplates. Also, the disc influences spinal height. The disc tissue is adapted for this biomechanical function. The function of the spine is impaired if there is a loss of disc tissue. Narrowing of the disc space due to degeneration of intervertebral discs is associated with a significantly increased risk of vertebral fractures. Estrogen should be seen as the first-choice therapy for bones and other collagen-rich tissues, such as intervertebral discs, because it maintains homeostasis of the bone-remodelling unit. Unlike bisphosphonates, estrogen is unique in its ability to regenerate bone collagen after its disintegration, apart from suppressing osteoclastic activity. Besides, there is insufficient data on deterioration in bone qualities and micro-cracks in patients on long-term bisphosphonates.

  11. Revision of hip resurfacing arthroplasty.

    Wera, Glenn D; Gillespie, Robert J; Petty, Carter; Petersilge, William J; Kraay, Matthew J; Goldberg, Victor M


    Metal-on-metal (MOM) hip resurfacing has become an increasingly popular treatment for young, active patients with degenerative disease of the hip, as bearing surfaces with better wear properties are now available. One proposed advantage of resurfacing is its ability to be successfully revised to total hip arthroplasty (THA). In addition, radiographic parameters that may predict failure in hip resurfacing have yet to be clearly defined. Seven MOM resurfacing arthroplasties were converted to conventional THAs because of aseptic failure. Using Harris Hip Scores (HHS) and Short Form 12 (SF-12) questionnaire scores, we compared the clinical outcomes of these patients with those of patients who underwent uncomplicated MOM hip resurfacing. In addition, all revisions were radiographically evaluated. Mean follow-up periods were 51 months (revision group) and 43 months (control group). There was no significant difference between the 2 groups' HHS or SF-12 scores. There was no dislocation or aseptic loosening after conversion of any resurfacing arthroplasty. Valgus neck-shaft angle (P hip resurfacing. Conversion of aseptic failure of hip resurfacing to conventional THA leads to clinical outcomes similar to those of patients who undergo uncomplicated hip resurfacing. The orientation of the femur and the components placed play a large role in implant survival in hip resurfacing. More work needs to be done to further elucidate these radiographic parameters.

  12. Humeral windows in revision total elbow arthroplasty

    Salama, Amir; Stanley, David


    The use of cortical windows for revision elbow arthroplasty has not previously been widely reported. Their use aids safe revision of a well fixed humeral prosthesis and can be used in the setting of dislocation, periprosthetic fracture or aseptic loosening of the ulnar component. We describe our technique and results of cortical windows in the distal humerus for revision elbow arthroplasty surgery. PMID:27583011

  13. Clinical study to evaluate the safety and effectiveness of the Aesculap Activ-L™ artificial disc in the treatment of degenerative disc disease

    Mo Fred F


    Full Text Available Abstract Background The objective of this clinical study is to evaluate the safety and effectiveness of the Activ-L Artificial Disc for treatment of single-level degenerative disc disease of the lumbar spine in patients who have been unresponsive to at least six months of prior conservative care. The hypothesis of the study is that the Activ-L Disc is non-inferior to the control (the Charité® Artificial Disc [DePuy Spine] or ProDisc-L® Total Disc Replacement [Synthes Spine] with respect to the rate of individual subject success at 24 months. Individual subject success is a composite of effectiveness and safety. Methods/Design The study proposed is a prospective, randomized, single-masked, controlled, multi-center clinical trial consisting of an estimated 414 subjects with single-level DDD of the lumbar spine (L4/L5, or L5/S1 who have failed to improve with conservative treatment for at least six months prior to enrollment. After enrollment, subjects will be randomized in a 2:1 ratio to either the Activ-L Disc (investigational device or the control (Charité or ProDisc-L. Radiographic endpoints will be evaluated by an independent reviewer at an imaging core laboratory. Each subject will be followed for 5 years post-treatment. Discussion The safety and effectiveness of the Activ-L Artificial Disc for treatment of single-level degenerative disc disease of the lumbar spine will be equivalent to Charité® Artificial Disc [DePuy Spine] or ProDisc-L® Total Disc Replacement [Synthes Spine] at 24 months. Trial Registration Current Controlled Trials NCT00589797.

  14. Hip Resurfacing Arthroplasty and Perioperative Blood Testing

    Andrew Cook


    Full Text Available It is standard practice in many institutions to routinely perform preoperative and postoperative haemoglobin level testing in association with hip joint arthroplasty procedures. It is our observation, however, that blood transfusion after uncomplicated primary hip arthroplasty in healthy patients is uncommon and that the decision to proceed with blood transfusion is typically made on clinical grounds. We therefore question the necessity and clinical value of routine perioperative blood testing about the time of hip resurfacing arthroplasty. We present analysis of perioperative blood tests and transfusion rates in 107 patients undertaking unilateral hybrid hip resurfacing arthroplasty by the senior author at a single institution over a three-year period. We conclude that routine perioperative testing of haemoglobin levels for hip resurfacing arthroplasty procedures does not assist in clinical management. We recommend that postoperative blood testing only be considered should the patient demonstrate clinical signs of symptomatic anaemia or if particular clinical circumstances necessitate.

  15. Knee Arthrodesis after failure of Knee Arthroplasty

    Gottfriedsen, Tinne B; Morville Schrøder, Henrik; Odgaard, Anders


    BACKGROUND: Arthrodesis is considered a salvage procedure after failure of a knee arthroplasty. Data on the use of this procedure are limited. The purpose of this study was to identify the incidence, causes, surgical techniques, and outcomes of arthrodesis after failed knee arthroplasty...... in a nationwide population. METHODS: Data were extracted from the Danish Civil Registration System, the Danish National Patient Register, and the Danish Knee Arthroplasty Register. A total of 92,785 primary knee arthroplasties performed in Denmark from 1997 to 2013 were identified by linking the data using....... Differences in cumulative incidence were compared with the Gray test. RESULTS: A total of 164 of the 165 arthrodeses were performed for causes related to failed knee arthroplasty. The 15-year cumulative incidence of arthrodesis was 0.26% (95% confidence interval, 0.21% to 0.31%). The 5-year cumulative...

  16. Heat distribution in disc brake

    Klimenda, Frantisek; Soukup, Josef; Kampo, Jan


    This article is deals by the thermal analysis of the disc brake with floating caliper. The issue is solved by numerically. The half 2D model is used for solution in program ADINA 8.8. Two brake discs without the ventilation are solved. One disc is made from cast iron and the second is made from stainless steel. Both materials are an isotropic. By acting the pressure force on the brake pads will be pressing the pads to the brake disc. Speed will be reduced (slowing down). On the contact surface generates the heat, which the disc and pads heats. In the next part of article is comparison the maximum temperature at the time of braking. The temperatures of both materials for brake disc (gray cast iron, stainless steel) are compares. The heat flux during braking for the both materials is shown.

  17. Dynamics of warped accretion discs

    Tremaine, Scott; Davis, Shane W.


    Accretion discs are present around both stellar-mass black holes in X-ray binaries and supermassive black holes in active galactic nuclei. A wide variety of circumstantial evidence implies that many of these discs are warped. The standard Bardeen--Petterson model attributes the shape of the warp to the competition between Lense--Thirring torque from the central black hole and viscous angular-momentum transport within the disc. We show that this description is incomplete, and that torques from...

  18. Intratracheal Seal Disc

    Christiansen, Karen Juelsgaard; Moeslund, Niels; Lauridsen, Henrik


    patient. The biosafety and feasibility of the device were evaluated in an animal model. METHODS: Five Danish Landrace pigs were subjected to tracheostomy followed by decannulation and insertion of the tracheostoma closure device. Correct placement of the device was ensured by flexible tracheoscopy...

  19. Cryotherapy Treatment After Unicompartmental and Total Knee Arthroplasty: A Review.

    Chughtai, Morad; Sodhi, Nipun; Jawad, Michael; Newman, Jared M; Khlopas, Anton; Bhave, Anil; Mont, Michael A


    Cryotherapy is widely utilized to enhance recovery after knee surgeries. However, the outcome parameters often vary between studies. Therefore, the purpose of this review is to compare (1) no cryotherapy vs cryotherapy; (2) cold pack cryotherapy vs continuous flow device cryotherapy; (3) various protocols of application of these cryotherapy methods; and (4) cost-benefit analysis in patients who had unicompartmental knee arthroplasty (UKA) or total knee arthroplasty (TKA). A search for "knee" and "cryotherapy" using PubMed, EBSCO Host, and SCOPUS was performed, yielding 187 initial reports. After selecting for RCTs relevant to our study, 16 studies were included. Of the 8 studies that compared the immediate postoperative outcomes between patients who did and did not receive cryotherapy, 5 studies favored cryotherapy (2 cold packs and 3 continuous cold flow devices). Of the 6 studies comparing the use of cold packs and continuous cold flow devices in patients who underwent UKA or TKA, 3 favor the use of continuous flow devices. There was no difference in pain, postoperative opioid consumption, or drain output between 2 different temperature settings of continuous cold flow device. The optimal device to use may be one that offers continuous circulating cold flow, as there were more studies demonstrating better outcomes. In addition, the pain relieving effects of cryotherapy may help minimize pain medication use, such as with opioids, which are associated with numerous potential side effects as well as dependence and addiction. Meta-analysis on the most recent RCTs should be performed next. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Numbered nasal discs for waterfowl

    Bartonek, J.C.; Dane, C.W.


    Numbered nasal discs were successfully used in studies requiring large numbers of individually marked waterfowl. The procedure for constructing these discs is outlined. Blue-winged teal (Anas discors) with 5/8-inch discs, and canvasback (Aythya valisineria) and redhead (A. americana) with 3/4-inch discs can be individually identified up to 50 and 80 yards, respectively, with a gunstock-mounted, 20-power spotting scope. The particular value of these markers is their durability, the number of combinations possible, and the apparent absence of behavioral or mortality influence among such species as the blue-winged teal.

  1. Optic disc drusen

    Fledelius, Hans C


    PURPOSE: To examine long-term data on optic disc drusen (ODD) from an outpatient hospital series that indicated more cases with advanced visual field constriction than is apparent from other clinical reports. The underlying pathophysiology is discussed, also with regard to enlarged blind spot...... neurosurgery for an arachnoid cyst. CONCLUSIONS: We found more cases of marked visual field constriction than reported in other clinical series. A few such cases appeared acute and vascular, but the main trend was clinically quiet over time. All 49 patients could manage visually in daily life....

  2. [Temporomandibular joint disc surgery].

    Potier, J; Maes, J-M; Nicot, R; Dumousseau, T; Cotelle, M; Ferri, J


    Temporomandibular joint (TMJ) disorders are a common disease and may be responsible for major functional and painful repercussions. Treatment is not consensual. The literature highlights the role of conservative treatments (physiotherapy, analgesics, splints) in a first attempt. Minimally invasive surgical techniques (arthroscopy, arthrocentesis) have developed rapidly in recent decades. They have proven effective and reliable, especially in patients suffering from irreducible or reducible anterior disc dislocation or presenting with arthopathies. The goal of our work was to make an update about disk surgery. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  3. Relativistic Disc lines

    Fabian, A C; Parker, M L


    Broad emission lines, particularly broad iron-K lines, are now commonly seen in the X-ray spectra of luminous AGN and Galactic black hole binaries. Sensitive NuSTAR spectra over the energy range of 3-78 keV and high frequency reverberation spectra now confirm that these are relativistic disc lines produced by coronal irradiation of the innermost accretion flow around rapidly spinning black holes. General relativistic effects are essential in explaining the observations. Recent results are briefly reviewed here.

  4. Treating the LDH(lumbar disc herniation )combined lumbar instability with half screw-stick haling device and a single cage for inter-vertebra union%单侧钉棒固定单枚Cage融合治疗腰椎间盘突出合并腰椎不稳症

    王亮; 朱冬承; 戈兵; 冯国新; 王晓民


    Objective To review the clinical curative effect of treating the lumbar disc hernia-tion combined lumbar instability through the operation which included enlarged laminactomy, double segment nerve canal decompression, fixation with half screw-stick device and single cage for inter vertebra union. Methods From Sept 2007 to Sept 2009,46 cases of lumbar disc herniation combined with lumbar instability were performed enlarged laminactomy and double segment nerve canal decompression,while these cases were fixed with half screw-stick device and single cage for inter vertebra union. Results All the cases were followed up for one to three years,averagely 2 years, according to the standard of Macnab's criteria,excellent 25 cases,good 8 cases,fair 3 cases and no bad cases,as the finess rate was 93.5%. Conclusion The operation by performing enlarged laminectomy and double segment nerve canal decompression, fixation with half screw-stick device and single cage for inter vertebra union,was an effective method for treatment of the lumbar disc herniation combined lumbar instability.%目的 观察扩大开窗两节段神经根管减压髓核摘除术加单侧钉棒系统固定单枚Cage椎间融合治疗腰椎间盘突出症合并腰椎不稳的临床疗效.方法 自2007-09-2009-09,对46例腰椎间盘突出症合并腰椎不稳患者采用扩大开窗两节段神经根管减压髓核摘除同时结合单侧椎弓根钉棒系统固定,单枚Cage椎间植骨融合.结果 本组随访观察1~3年,平均2年,根据Macnab疗效评定标准:优25例,良18例,可3例,差0例,优良率93.5%,结论采用扩大开窗两节段神经根管减压髓核摘除术加单侧钉棒系统固定单枚Cage椎间融合是治疗腰椎间盘突出症合并腰椎不稳的有效方法.

  5. Design of the PROCON trial: a prospective, randomized multi – center study comparing cervical anterior discectomy without fusion, with fusion or with arthroplasty

    Grotenhuis J André


    Full Text Available Abstract Background PROCON was designed to assess the clinical outcome, development of adjacent disc disease and costs of cervical anterior discectomy without fusion, with fusion using a stand alone cage and implantation of a Bryan's disc prosthesis. Description of rationale and design of PROCON trial and discussion of its strengths and limitations. Methods/Design Since proof justifying the use of implants or arthroplasty after cervical anterior discectomy is lacking, PROCON was designed. PROCON is a multicenter, randomized controlled trial comparing cervical anterior discectomy without fusion, with fusion with a stand alone cage or with implantation of a disc. The study population will be enrolled from patients with a single level cervical disc disease without myelopathic signs. Each treatment arm will need 90 patients. The patients will be followed for a minimum of five years, with visits scheduled at 6 weeks, 3 months, 12 months, and then yearly. At one year postoperatively, clinical outcome and self reported outcomes will be evaluated. At five years, the development of adjacent disc disease will be investigated. Discussion The results of this study will contribute to the discussion whether additional fusion or arthroplasty is needed and cost effective. Trial registration Current Controlled Trials ISRCTN41681847

  6. Centrifugally driven microfluidic disc for detection of chromosomal translocations

    Brøgger, Anna Line; Kwasny, Dorota; Bosco, Filippo G.


    and prognosis of patients. In this work we demonstrate a novel, centrifugally-driven microfluidic system for controlled manipulation of oligonucleotides and subsequent detection of chromosomal translocations. The device is fabricated in the form of a disc with capillary burst microvalves employed to control...

  7. Comparative experiments on the technological performance of disc filters

    Liu, Guangrong; Jiang, Hua; Liao, Dongmei; Deng, Yingchun


    The filtration performance of JY disc filters was compared with that of Arkal disc filters when a parallel filtration system was designed under lab-scale devices. The comparisons of working and backwash performance were made for different filtration level. The experimental results showed that the two kinds of filters had similar process performance and effluent water quality under the same experimental condition. JY filter has higher filter performance index (FPI) than Arkal disc filters with the micron rating from 20 to 55μm discs, on the other hand, FPI value of JY filter has lower FPI than Arkal disc filters with the micron rating from 100 to 200μm discs. The removal rates of suspended solid(SS) for both filters vary in the range from 64% to 91.5%, moreover, the mean removal rate of SS for JY and Arkal filter was 78.2% and 79% respectively. The removal rates of turbidity were lower than 13% and the mean removal rate of turbidity was 7% for both filters. The critical backwash time and the critical backwash water loss for both filters were 5 seconds and 15 litres respectively.

  8. Accretion discs trapped near corotation

    D'Angelo, C.R.; Spruit, H.C.


    We show that discs accreting on to the magnetosphere of a rotating star can end up in a trapped state, in which the inner edge of the disc stays near the corotation radius, even at low and varying accretion rates. The accretion in these trapped states can be steady or cyclic; we explore these states

  9. Dislocation following revision total hip arthroplasty.

    Gioe, Terence J


    Dislocation is a relatively common complication following revision total hip arthroplasty. Risk factors include surgical approach, gender, underlying diagnosis, comorbidities, surgical experience, and previous surgery; for later dislocations, risk factors include wear/deformation of polyethylene, trauma, and decreased muscle strength. Prevention and precaution are the watchwords for dislocations following revision total hip arthroplasty. For dislocations that do occur, treatment rests first on identifying the source of instability. Most dislocations can be managed by closed reduction. Constrained components may increase success rates, but only for appropriate indications. Prevention and treatment of dislocations following revision total hip arthroplasty are discussed in this article.

  10. Intraoral micro-identification discs.

    Hansen, R W


    Intraoral micro-identification discs have recently been utilized to provide a more permanent method of personal identification. A wafer of plastic or metal with a surface area of 2.5 to 5 mm2 and carrying identifying numbers and/or letters (indicia) is bonded to the buccal enamel surface of the posterior teeth. Personal identification can occur after the I.D. disc is identified and the indicia is read. Reading of photoreduced indicia requires the aid of a microscope subsequent to the removal of the microdisc. In situ reading of disc indicia is possible using low power handheld magnifiers if the size of the indicia approximates 0.3 mm. Computerization is an integral part of non-custom alpha/numeric type designs, but a custom disc carries a name, address, and other specific information unique to the manufacturer. The use of a computer improves access to the database and it decreases the amount of data placed on the disc. Microdisc bases may be fabricated using a mylar type plastic or they may be manufactured from a stainless steel blank. Plastic discs are constructed with an internal sandwich containing the photo-reduced indicia. Metal discs are marked with a photochemical etch or engraved with a computer driven YAG laser. Attachment of the disc to the enamel surface is accomplished by conventional etching and bonding techniques and are typically bonded to the buccal surface of the maxillary first permanent molar or the second primary molar. Clear composite bonding material covers the disc so that salivary contamination does not result in degradation of the indicia. Orthodontic style discs with a mesh back carry laser written information that may be cemented with conventional orthodontic bonding cement. Standardization of the indicia and overall design is considered to be an important aspect of patient and professional acceptance.

  11. Evolution of protoplanetary discs with magnetically driven disc winds

    Suzuki, Takeru K.; Ogihara, Masahiro; Morbidelli, Alessandro; Crida, Aurélien; Guillot, Tristan


    Aims: We investigate the evolution of protoplanetary discs (PPDs) with magnetically driven disc winds and viscous heating. Methods: We considered an initially massive disc with 0.1 M⊙ to track the evolution from the early stage of PPDs. We solved the time evolution of surface density and temperature by taking into account viscous heating and the loss of mass and angular momentum by the disc winds within the framework of a standard α model for accretion discs. Our model parameters, turbulent viscosity, disc wind mass-loss, and disc wind torque, which were adopted from local magnetohydrodynamical simulations and constrained by the global energetics of the gravitational accretion, largely depends on the physical condition of PPDs, particularly on the evolution of the vertical magnetic flux in weakly ionized PPDs. Results: Although there are still uncertainties concerning the evolution of the vertical magnetic flux that remains, the surface densities show a large variety, depending on the combination of these three parameters, some of which are very different from the surface density expected from the standard accretion. When a PPD is in a wind-driven accretion state with the preserved vertical magnetic field, the radial dependence of the surface density can be positive in the inner region migration of protoplanets. Conclusions: The variety of our calculated PPDs should yield a wide variety of exoplanet systems.

  12. Comparison of in vivo and simulator-retrieved metal-on-metal cervical disc replacements

    Kurtz, Steven M.; Ciccarelli, Lauren; Harper, Megan L.; Siskey, Ryan; Shorez, Jacob; Chan, Frank W.


    Background Cervical disc arthroplasty is regarded as a promising treatment for myelopathy and radiculopathy as an alternative to cervical spine fusion. On the basis of 2-year clinical data for the PRESTIGE® Cervical Disc (Medtronic, Memphis, Tennessee), the Food and Drug Administration recommended conditional approval in September 2006 and final approval in July 2007; however, relatively little is known about its wear and damage modes in vivo. The main objective was to analyze the tribological findings of the PRESTIGE® Cervical Disc. This study characterized the in vivo wear patterns of retrieved cervical discs and tested the hypothesis that the total disc replacements exhibited similar surface morphology and wear patterns in vitro as in vivo. Methods Ten explanted total disc replacements (PRESTIGE®, PRESTIGE® I, and PRESTIGE® II) from 10 patients retrieved after a mean of 1.8 years (range, 0.3–4.1 years) were analyzed. Wear testing included coupled lateral bending ( ±4.7°) and axial rotation ( ±3.8°) with a 49 N axial load for 5 million cycles followed by 10 million cycles of flexion-extension ( ±9.7°) with 148 N. Implant surfaces were characterized by the use of white-light interferometry, scanning electron microscopy, and energy dispersive spectroscopy. Results The explants generally exhibited a slightly discolored, elliptic wear region of varying dimension centered in the bearing center, with the long axis oriented in the medial-lateral direction. Abrasive wear was the dominant in vivo wear mechanism, with microscopic scratches generally oriented in the medial-lateral direction. Wear testing resulted in severe abrasive wear in a curvilinear fashion oriented primarily in the medial-lateral direction. All retrievals showed evidence of an abrasive wear mechanism. Conclusions This study documented important similarity between the wear mechanisms of components tested in vitro and explanted PRESTIGE® Cervical Discs; however, the severity of wear was

  13. Continuous-flow cold therapy after total knee arthroplasty.

    Morsi, Elsayed


    Cryotherapy is widely used as an emergency treatment of sports trauma and postoperatively especially after anterior cruciate ligament reconstruction. Studies in the literature on the effect of cryotherapy after total knee arthroplasty (TKA) have been limited and controversial. In this prospective study, 60 primary TKAs were done on 30 patients (all staged bilateral TKAs). For every patient, 1 TKA had a continuous-flow cooling device applied over the surgical dressing immediately postoperatively. The other TKA in the same patient (control TKA) was done 6 weeks later and had no cooling device. The study compared the range of motion, the volume of hemovac output and blood loss, visual analog pain score, analgesic consumption, and wound healing in the 2 limbs of the same patient. This study showed that continuous-flow cold therapy is advantageous after TKA because it provides better results in all the areas compared.


    Lou, Jigang; Liu, Hao; Rong, Xin; Gong, Quan; Song, Yueming; Li, Tao


    To evaluate the effectiveness of the single segmental cervical disc replacement with ProDisc-C, and to explore the location change of the flexion/extension center of rotation (COR) of the target level as well as its clinical significance. Between June 2010 and February 2012, 23 patients underwent single segmental cervical disc replacement with ProDisc-C, and the clinical data were retrospectively analyzed. Of 23 patients, 9 were male, and 14 were female with the age range from 27 to 65 years (mean, 45 years), and the disease duration ranged from 10 to 84 months (mean, 25 months). There were 15 patients with radiculopathy, 5 patients with myelopathy, and 3 patients with mixed cervical spondylosis. The involved segments were C4,5 in 5 cases, C5,6 in 14 cases, and C6,7 in 4 cases. Japanese Orthopaedic Association (JOA) score and neck disability index (NDI) were adopted to evaluate the effectiveness. Preoperative and Postoperative radiographic parameters, such as cervical overall range of motion (ROM), target segmental ROM, the adjacent segmental ROM, and intervertebral height were compared. Besides, the location changes of the COR of the target level were further analyzed by the alteration of its coordinates (COR-X, COR-Y), and the relationships between the location changes of the COR and the effectiveness or the radiographic results were analyzed. All the operations were completed successfully; 1 case had hoarseness after operation, which disappeared at 3 months after operation. All cases were followed up 18.3 months on average (range, 6-36 months). There was no device migration, loosening, subsidence, or fracture at last follow-up. The JOA score increased significantly and the NDI score decreased significantly at last follow-up when compared with preoperative scores (P 0.05); while the intervertebral height and the COR-X increased significantly (P 0.05). According to whether the difference of the COR-X between pre- and post-operation was less than the average value

  15. Heterotopic ossification associated with myelopathy following cervical disc prosthesis implantation.

    Wenger, Markus; Markwalder, Thomas-Marc


    This case report presents a 37-year-old man with clinical signs of myelopathy almost 9 years after implantation of a Bryan disc prosthesis (Medtronic Sofamor Danek, Memphis, TN, USA) for C5/C6 soft disc herniation. As demonstrated on MRI and CT scan, spinal cord compression was caused by bony spurs due to heterotopic ossification posterior to the still moving prosthesis. The device, as well as the ectopic bone deposits, had to be removed because of myelopathy and its imminent aggravation. Conversion to anterior spondylodesis was performed.

  16. Coevolution of Binaries and Gaseous Discs

    Fleming, David P


    The recent discoveries of circumbinary planets by $\\it Kepler$ raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary protoplanetary disc, and how the disc and binary interact and change as a result. The central binary excites resonances in the surrounding protoplanetary disc that drive evolution in both the binary orbital elements and in the disc. To probe how these interactions impact binary eccentricity and disc structure evolution, N-body smooth particle hydrodynamics (SPH) simulations of gaseous protoplanetary discs surrounding binaries based on Kepler 38 were run for $10^4$ binary periods for several initial binary eccentricities. We find that nearly circular binaries weakly couple to the disc via a parametric instability and excite disc eccentricity growth. Eccentric binaries strongly couple to the disc causing eccentricity growth for both the disc and binary. Discs around sufficiently eccentri...

  17. Revision of failed humeral head resurfacing arthroplasty

    Philipp N Streubel


    Conclusion: Outcomes of revision of HHR arthroplasty in this cohort did not improve upon those reported for revision of stemmed humeral implants. A comparative study would be required to allow for definitive conclusions to be made.

  18. Wear debris in cemented total hip arthroplasty.

    Huo, M H; Salvati, E A; Buly, R L


    One of the most prevalent clinical problems in long-term follow up of total hip arthroplasty patients is loosening of prosthetic fixation. Factors contributing to mechanical failure of total hip reconstruction are complex and multiple. It has become increasingly apparent that wear debris from the prosthetic components may contribute significantly to this process. The authors summarize some of the current concepts concerning the detrimental effects of metallic debris in total hip arthroplasty.

  19. Total Ankle Arthroplasty: A Brief Review

    Mann, Roger A.; Harrison, Matthew J.


    Ankle fusion has long been the standard of treatment for end-stage ankle arthritis, and a successful arthroplasty has been a long sought alternative. It is a motion sparing procedure and may greatly reduce the potential for adjacent level degeneration as seen with arthrodesis. The typical candidate for arthroplasty is a healthy low demand patient, although the indications are widening as the success of the procedure has increased. Nevertheless, it is not fail-safe, technical expertise and exp...

  20. Accretion discs trapped near corotation

    D'Angelo, C.R.; Spruit, H.C.


    We show that discs accreting on to the magnetosphere of a rotating star can end up in a trapped state, in which the inner edge of the disc stays near the corotation radius, even at low and varying accretion rates. The accretion in these trapped states can be steady or cyclic; we explore these states over a wide range of parameter space. We find two distinct regions of instability: one related to the buildup and release of mass in the disc outside corotation, and the other to mass storage with...

  1. MR Imaging of Knee Arthroplasty Implants

    Fritz, Jan; Lurie, Brett


    Primary total knee arthroplasty is a highly effective treatment that relieves pain and improves joint function in a large percentage of patients. Despite an initially satisfactory surgical outcome, pain, dysfunction, and implant failure can occur over time. Identifying the etiology of complications is vital for appropriate management and proper timing of revision. Due to the increasing number of knee arthroplasties performed and decreasing patient age at implantation, there is a demand for accurate diagnosis to determine appropriate treatment of symptomatic joints following knee arthroplasty, and for monitoring of patients at risk. Magnetic resonance (MR) imaging allows for comprehensive imaging evaluation of the tissues surrounding knee arthroplasty implants with metallic components, including the polyethylene components. Optimized conventional and advanced pulse sequences can result in substantial metallic artifact reduction and afford improved visualization of bone, implant-tissue interfaces, and periprosthetic soft tissue for the diagnosis of arthroplasty-related complications. In this review article, we discuss strategies for MR imaging around knee arthroplasty implants and illustrate the imaging appearances of common modes of failure, including aseptic loosening, polyethylene wear–induced synovitis and osteolysis, periprosthetic joint infections, fracture, patellar clunk syndrome, recurrent hemarthrosis, arthrofibrosis, component malalignment, extensor mechanism injury, and instability. A systematic approach is provided for evaluation of MR imaging of knee implants. MR imaging with optimized conventional pulse sequences and advanced metal artifact reduction techniques can contribute important information for diagnosis, prognosis, risk stratification, and surgical planning. ©RSNA, 2015 PMID:26295591

  2. Shock absorption in lumbar disc prosthesis: a preliminary mechanical study.

    LeHuec, J C; Kiaer, T; Friesem, T; Mathews, H; Liu, M; Eisermann, L


    Lumbar disc prostheses have been used in treating symptomatic degenerative disc diseases. A few prostheses of the ball-socket design are currently available for clinical use, the joint mechanism being materialized either with a hard polymer core or a metal-to-metal couple. Other prostheses of "shock absorber" design were not available at the time of the study. The objective of this work was to establish whether there was a difference in the shock absorption capacity between a device having an ultra-high-molecular-weight polyethylene center core and a device having a metal-on-metal bearing. Vibration and shock loading were applied to two lumbar total disc prostheses: PRODISC, manufactured by Spine Solutions, and MAVERICK Total Disc Replacement, manufactured by Medtronic Sofamor Danek. The shock absorption capacity of the device was evaluated by comparing the input and the output force measurements. The disc prosthesis was mounted onto a test apparatus. Each side of the device was equipped with a force sensor. The input shock load and the output resulting forces were simultaneously measured and recorded. The loading force pattern included 1). a static preload of 350 N plus an oscillating vibration of 100 N with frequency sweeping from 0 to 100 Hz and 2). a sudden shock load of 250 N applied over a 0.1-second interval. Both input and output signal data were processed and were transformed into their frequency spectrums. The vibration and shock transmissibility of the device, defined as the ratio of the output spectrum over the input spectrum, were calculated in sweeping the frequency from 0 to 100 Hz. The phase deviation was calculated to characterize the shock absorber effects. For both tested devices under vibration and shock loading, the phase angle displacement between the input and the output signals was 10 degrees. Under oscillating vibration loading, both tested devices had a transmission ratio higher than 99.8%. Over the frequency interval 1-100 Hz, the

  3. Revision total elbow arthroplasty with the linked Coonrad-Morrey total elbow arthroplasty

    Plaschke, Hans Christian; Thillemann, Theis; Belling-Sørensen, Anne Kathrine;


    In this retrospective study we evaluated the short- to medium-term results after 20 Coonrad-Morrey revision total elbow arthroplasties (TEAs).......In this retrospective study we evaluated the short- to medium-term results after 20 Coonrad-Morrey revision total elbow arthroplasties (TEAs)....

  4. Clinical outcome after treatment of infected primary total knee arthroplasty

    Husted, Henrik; Jensen, Tim Toftgaard


    Twenty-six consecutive cases of infected primary total knee arthroplasties were treated at our institution from 1989 through 2000. Eleven patients had debridement and irrigation performed within 2 months of index arthroplasty or hematogenous spread; only one infection was eradicated. Twenty......-five patients had their prostheses removed; 17 had two-stage revision arthroplasty, following which infection was eradicated in 15; one had a permanent spacer, 7 had arthrodesis (following failed revision arthroplasty in one) and 2 had a femur amputation (following failed revision arthroplasty in one) at follow......-up of mean 24 months. Infections were cured equally well with revision arthroplasty and arthrodesis. Among the 15 patients who ended up with revision arthroplasty, 11 had a better range of motion compared to the index arthroplasty, but 8 had daily pain. We present our treatment protocol, which eradicated 15...

  5. Joint Line Reconstruction in Navigated Total Knee Arthroplasty Revision


    Revision Total Knee Arthroplasty Because of; Loosening; Instability; Impingement; or Other Reasons Accepted as Indications for TKA Exchange.; The Focus is to Determine the Precision of Joint Line Restoration in Navigated vs. Conventional Revision Total Knee Arthroplasty

  6. Multivariate Analysis of Blood Transfusion Rates After Shoulder Arthroplasty.

    King, Joseph J; Patrick, Matthew R; Schnetzer, Ryan E; Farmer, Kevin W; Struk, Aimee M; Garvan, Cyndi; Wright, Thomas W

    A retrospective review was performed of all shoulder arthroplasties with patients grouped on the basis of transfusion protocol time period. Group 1 had transfusions if postoperative hematocrit was multivariate analysis of significant bivariate factors were performed. Protocol change decreased transfusion rates from 16% (group 1, 153 arthroplasties) to 8% (group 2, 149 arthroplasties). Reverse shoulder arthroplasty (RTSA) transfusion rate decreased dramatically (from 24% to 5%). Transfusion rates after total shoulder arthroplasty (TSA) were low (4%) and after revision arthroplasty were high (21% + 27%) in both groups. Age, gender, heart disease, preoperative hematocrit, diagnosis, and estimated blood loss (EBL) were risk factors on bivariate analysis. Failed arthroplasty and fracture diagnoses carried high transfusion rates (25% + 28%). Logistic regression showed that low preoperative hematocrit, increased EBL, revision arthroplasty, and heart disease were transfusion risk factors. Protocol based on symptomatic anemia results in low transfusion rates after primary TSA and RTSA.

  7. Eclipse mapping of accretion discs

    Baptista, R


    The eclipse mapping method is an inversion technique that makes use of the information contained in eclipse light curves to probe the structure, the spectrum and the time evolution of accretion discs. In this review I present the basics of the method and discuss its different implementations. I summarize the most important results obtained to date and discuss how they have helped to improve our understanding of accretion physics, from testing the theoretical radial brightness temperature distribution and measuring mass accretion rates to showing the evolution of the structure of a dwarf novae disc through its outburst cycle, from isolating the spectrum of a disc wind to revealing the geometry of disc spiral shocks. I end with an outline of the future prospects.

  8. Vortex migration in protoplanetary discs

    Papaloizou John C. B.


    Full Text Available Vortices embedded in protoplanetary discs can act as obstacles to the unperturbed disc flow. The resulting velocity perturbations propagate away from the vortex in the form of density waves that transport angular momentum. Any asymmetry between the inner and the outer density wave means that the region around the vortex has to change its angular momentum. We find that this leads to orbital migration of the vortex. Asymmetric waves always arise except in the case of a disc with constant pressure, for isothermal as well as non-isothermal discs. Depending on the size and strength of the vortex, the resulting migration time scales can be as short as a few thousand orbits.

  9. Modelling Neutral Hydrogen Discs of Spiral Galaxies

    林伟鹏; 洪碧海


    We present an analytical model of a neutral hydrogen disc in a spiral galaxy. The gas disc of the spiral galaxy isassumed to have an exponential surface density profile and to be ionized by the cosmic ultraviolet background.To compare with observations, we consider the disc position angle and inclination angle for a line of sight goingthrough the galaxy disc. The HI column densities depend on the strength of ionizing field and disc position andinclination. The model was applied to NGC 3198 and the results were compared with observational data. TheHI disc profile at large disc radii can be tested by further HI observations using radio telescopes with a largeraperture than the present facilities. This HI disc model can be used to predict quasar absorption line systems bygalaxy discs if quasar lines of sight go through the discs.

  10. Debris disc formation induced by planetary growth

    Kobayashi, Hiroshi


    Several hundred stars older than 10 million years have been observed to have infrared excesses. These observations are explained by dust grains formed by the collisional fragmentation of hidden planetesimals. Such dusty planetesimal discs are known as debris discs. In a dynamically cold planetesimal disc, collisional coagulation of planetesimals produces planetary embryos which then stir the surrounding leftover planetesimals. Thus, the collisional fragmentation of planetesimals that results from planet formation forms a debris disc. We aim to determine the properties of the underlying planetesimals in debris discs by numerically modelling the coagulation and fragmentation of planetesimal populations. The brightness and temporal evolution of debris discs depend on the radial distribution of planetesimal discs, the location of their inner and outer edges, their total mass, and the size of planetesimals in the disc. We find that a radially narrow planetesimal disc is most likely to result in a debris disc that ...

  11. Health-related quality of life in veterans with prevalent total knee arthroplasty and total hip arthroplasty

    Singh, J.A.; Sloan, J.A.


    Objective. To study the HRQOL in veterans with prevalent total knee arthroplasty (TKA) or total hip arthroplasty (THA) and compare them with age- and gender-matched US population and control veteran population without these procedures.

  12. Photon Bubbles in Accretion Discs

    Gammie, Charles F.


    We show that radiation dominated accretion discs are likely to suffer from a ``photon bubble'' instability similar to that described by Arons in the context of accretion onto neutron star polar caps. The instability requires a magnetic field for its existence. In an asymptotic regime appropriate to accretion discs, we find that the overstable modes obey the remarkably simple dispersion relation \\omega^2 = -i g k F(B,k). Here g is the vertical gravitational acceleration, B the magnetic field, ...

  13. Self-gravitating accretion discs

    Lodato, G.


    I review recent progresses in the dynamics and the evolution of self-gravitating accretion discs. Accretion discs are a fundamental component of several astrophysical systems on very diverse scales, and can be found around supermassive black holes in Active Galactic Nuclei (AGN), and also in our Galaxy around stellar mass compact objects and around young stars. Notwithstanding the specific differences arising from such diversity in physical extent, all these systems share a common feature whe...

  14. Static progressive stretch improves range of motion in arthrofibrosis following total knee arthroplasty.

    Bonutti, Peter M; Marulanda, German A; McGrath, Mike S; Mont, Michael A; Zywiel, Michael G


    Arthrofibrosis is a relatively common complication after total knee arthroplasty that negatively affects function and quality of life. Static progressive stretching is a technique that has shown promising results in the treatment of contractures of the elbow, ankle, wrist and knee. This study evaluated a static progressive stretching device as a treatment method for patients who had refractory knee stiffness after total knee arthroplasty. Twenty-five patients who had knee stiffness and no improvement with conventional physical therapy modalities were treated with the device. After a median of 7 weeks (range, 3-16 weeks), the median increase in range of motion was 25 degrees (range, 8-82 degrees). The median gain in knee active flexion was 19 degrees (range, 5-80 degrees). Ninety-two percent of patients were satisfied with the results. The authors believe static progressive stretching devices may be an effective method for increasing the ranges of motion and satisfaction levels of patients who develop arthrofibrosis after total knee arthroplasty.


    Ravi B. Solanki


    Full Text Available Arthrofibrosis following total knee arthroplasty is an uncommon complication defined as less than 80 degrees of knee flexion 6-8 weeks post operatively. It is characterized by abnormal scarring of the joint in which the formation of dense fibrous tissue and tissue metaplasia prevent normal range of motion. Clinical features include limited knee Range of motion with extension deficit, pain with activities of daily living and unusual amount of pain and swelling post operatively in the absence of infection, bleeding or mechanical complications. We present case of 55 years old female who undergone for total knee replacement before 3 months and presented to our department with complain of knee pain and swelling with activities of daily living. She was diagnosed on the basis of clinical examination. Her detailed evaluation was carried out and Physiotherapy treatment was started.

  16. 曲度邦腰椎牵引仪配合活血中药外敷治疗腰椎间盘突出症的疗效研究%Efficacy of Posture Pump Lumbar Traction Device Cooperated with Huoxue Traditional Chinese Medicine for External Use in Treating Lumbar Disc Herniation

    郭瑞清; 刘玉耆; 高磊; 周斌; 苏广志


    目的 研究曲度邦腰椎牵引仪配合活血中药外敷治疗腰椎间盘突出症的疗效. 方法 将随机选取2012年5月—2014年6月期间该院接受保守治疗的120例腰椎间盘突出症患者随机分为两组, 干预组接受曲度邦腰椎牵引仪配合活血中药外敷治疗、对照组仅接受曲度邦腰椎牵引仪治疗. 治疗后,测定两组患者的腰椎疼痛程度、活动程度和功能情况. 结果 干预组患者的JOA评分(16.69±2.14),高于对照组的(11.47±1.57);ODI评分(16.87±2.06),低于对照组的(23.45±4.29);腰椎活动角度均高于对照组. 结论 曲度邦腰椎牵引仪配合活血中药外敷治疗能够缓解腰痛程度、增强腰椎功能和活动度,是腰椎间盘突出症相对更为理想的保守治疗方法.%Objective To study the curvature efficacy of Posture Pump lumbar traction device cooperated with Huoxue traditional Chinese medicine (TCM) for exteranal use in treating lumbar disc herniation. Methods 120 patients with lumbar disc herniation who received conservative treatment in our hospital from May 2012 to June 2014 were randomly divided into two groups. The in-tervention group was treated with Posture Pump lumbar traction device cooperated with Huoxue TCM for external use, while the control group only underwent treatment with Posture Pump lumbar traction device. After treatment, lumbar's pain, activities and functions were compared. Results JOA score (16.69±2.14) of the intervention group was higher than (11.47±1.57) of the control group, ODI score (16.87±2.06) of the intervention group was lower than (23.45±4.29) of the control group; lumbar spine angles of the in-tervation group were higher than those of the control group. Conclusion Posture Pump lumbar traction device cooperated with Huoxue TCM for external use can alleviate back pain level, enhance lumbar function and activity, and it is relatively more desir-able conservative treatment for lumbar disc herniation.

  17. Disc piezoelectric ceramic transformers.

    Erhart, Jirií; Půlpán, Petr; Doleček, Roman; Psota, Pavel; Lédl, Vít


    In this contribution, we present our study on disc-shaped and homogeneously poled piezoelectric ceramic transformers working in planar-extensional vibration modes. Transformers are designed with electrodes divided into wedge, axisymmetrical ring-dot, moonie, smile, or yin-yang segments. Transformation ratio, efficiency, and input and output impedances were measured for low-power signals. Transformer efficiency and transformation ratio were measured as a function of frequency and impedance load in the secondary circuit. Optimum impedance for the maximum efficiency has been found. Maximum efficiency and no-load transformation ratio can reach almost 100% and 52 for the fundamental resonance of ring-dot transformers and 98% and 67 for the second resonance of 2-segment wedge transformers. Maximum efficiency was reached at optimum impedance, which is in the range from 500 Ω to 10 kΩ, depending on the electrode pattern and size. Fundamental vibration mode and its overtones were further studied using frequency-modulated digital holographic interferometry and by the finite element method. Complementary information has been obtained by the infrared camera visualization of surface temperature profiles at higher driving power.

  18. Resonances in retrograde circumbinary discs

    Nixon, Chris


    We analyse the interaction of an eccentric binary with a circular coplanar circumbinary disc that rotates in a retrograde sense with respect to the binary. In the circular binary case, no Lindblad resonances lie within the disc and no Lindblad resonant torques are produced, as was previously known. By analytic means, we show that when the binary orbit is eccentric, there exist components of the gravitational potential of the binary which rotate in a retrograde sense to the binary orbit and so rotate progradely with respect to this disc, allowing a resonant interaction to occur between the binary and the disc. The resulting resonant torques distinctly alter the disc response from the circular binary case. We describe results of three-dimensional hydrodynamic simulations to explore this effect and categorise the response of the disc in terms of modes whose strengths vary as a function of binary mass ratio and eccentricity. These mode strengths are weak compared to the largest mode strengths expected in the prog...

  19. Lumbar disc excision through fenestration

    Sangwan S


    Full Text Available Background : Lumbar disc herniation often causes sciatica. Many different techniques have been advocated with the aim of least possible damage to other structures while dealing with prolapsed disc surgically in the properly selected and indicated cases. Methods : Twenty six patients with clinical symptoms and signs of prolapsed lumbar intervertebral disc having radiological correlation by MRI study were subjected to disc excision by interlaminar fenestration method. Results : The assessment at follow-up showed excellent results in 17 patients, good in 6 patients, fair in 2 patients and poor in 1 patient. The mean preoperative and postoperative Visual Analogue Scores were 9.34 ±0.84 and 2.19 ±0.84 on scale of 0-10 respectively. These were statistically significant (p value< 0.001, paired t test. No significant complications were recorded. Conclusion : Procedures of interlaminar fenestration and open disc excision under direct vision offers sufficient adequate exposure for lumbar disc excision with a smaller incision, lesser morbidity, shorter convalescence, early return to work and comparable overall results in the centers where recent laser and endoscopy facilities are not available.

  20. Counter-Rotating Accretion Discs

    Dyda, Sergei; Ustyugova, Galina V; Romanova, Marina M; Koldoba, Alexander V


    Counter-rotating discs can arise from the accretion of a counter-rotating gas cloud onto the surface of an existing co-rotating disc or from the counter-rotating gas moving radially inward to the outer edge of an existing disc. At the interface, the two components mix to produce gas or plasma with zero net angular momentum which tends to free-fall towards the disc center. We discuss high-resolution axisymmetric hydrodynamic simulations of a viscous counter-rotating disc for cases where the two components are vertically separated and radially separated. The viscosity is described by an isotropic $\\alpha-$viscosity including all terms in the viscous stress tensor. For the vertically separated components a shear layer forms between them. The middle of this layer free-falls to the disk center. The accretion rates are increased by factors $\\sim 10^2-10^4$ over that of a conventional disc rotating in one direction with the same viscosity. The vertical width of the shear layer and the accretion rate are strongly dep...

  1. Instability following total knee arthroplasty.

    Rodriguez-Merchan, E Carlos


    Background Knee prosthesis instability (KPI) is a frequent cause of failure of total knee arthroplasty. Moreover, the degree of constraint required to achieve immediate and long-term stability in total knee arthroplasty (TKA) is frequently debated. Questions This review aims to define the problem, analyze risk factors, and review strategies for prevention and treatment of KPI. Methods A PubMed (MEDLINE) search of the years 2000 to 2010 was performed using two key words: TKA and instability. One hundred and sixty-five initial articles were identified. The most important (17) articles as judged by the author were selected for this review. The main criteria for selection were that the articles addressed and provided solutions to the diagnosis and treatment of KPI. Results Patient-related risk factors predisposing to post-operative instability include deformity requiring a large surgical correction and aggressive ligament release, general or regional neuromuscular pathology, and hip or foot deformities. KPI can be prevented in most cases with appropriate selection of implants and good surgical technique. When ligament instability is anticipated post-operatively, the need for implants with a greater degree of constraint should be anticipated. In patients without significant varus or valgus malalignment and without significant flexion contracture, the posterior cruciate ligament (PCL) can be retained. However, the PCL should be sacrificed when deformity exists particularly in patients with rheumatoid arthritis, previous patellectomy, previous high tibial osteotomy or distal femoral osteotomy, and posttraumatic osteoarthritis with disruption of the PCL. In most cases, KPI requires revision surgery. Successful outcomes can only be obtained if the cause of KPI is identified and addressed. Conclusions Instability following TKA is a common cause of the need for revision. Typically, knees with deformity, rheumatoid arthritis, previous patellectomy or high tibial osteotomy, and

  2. The innovation trap: modular neck in total hip arthroplasty

    Samo Karel Fokter


    Full Text Available Background: Innovations play the key role in the success of orthopaedic surgery. However, even minor modifications in the established concepts and proven designs may result in disasters. The endemic of modular femoral neck fracture (24 cases of about 4000 implanted in fully modular total hip arthroplasty, popular in our country for the last 20 years, seems to challenge us with such an unfortunate consequences. The aim of this report was to analyze the extent and the causes of the problem on the one hand and to propose possible solutions on the other.Methods: Literature search for problems associated with Profemur Z (or earlier versions with the same taper-cone design fully-modular femoral stem made of titanium alloy (Ti6Al4V was performed, and hip arthroplasty registries were searched to evaluate the failure rates of the mentioned design. Mechanisms of failure were studied to get in-depth understanding of this particular hip reconstruction device.Results: Since 2010 onwards, several case reports on catastrophic modular femoral neck fractures of Profemur Z were published. Te frst Slovenian case was described in 2012. The first two larger series with modular femoral neck fractures were published in 2016. Te Australian Joint Replacement Registry was the first to discover increased revision rates due to fractures of this hip reconstruction system. Public Agency of the Republic of Slovenia for Medicinal Products and Medical Devices (JAZMP received frst two reports regarding Profemur Z modular neck complication from abroad in 2010, the first Slovenian report was received in 2012, and altogether 7 reports from Slovenian hospitals were received until December 2016. Corrosion at the neck-taper interface, where two equal or different materials are subject to constant wear in the presence of body fluids, is assumed to be responsible for the unacceptable high failure rate.Conclusions: Manufacturers are responsible to produce and market only safe devices

  3. Analyses of the temporomandibular disc.

    Jirman, R; Fricová, M; Horák, Z; Krystůfek, J; Konvicková, S; Mazánek, J


    This project is the beginning of a large research work with a goal to develop a new total replacement of temporomandibular (TM) joint. First aim of this work was to determine the relative displacement of the TM disc and the mandible during mouth opening. The movement of the TM disc was studied using a magnetic resonance imaging. Sagittal static images in revolved sections of the TM joint were obtained in various positions of jaw opening from 0 to 50 mm. The results provided a description of the TM disc displacements as a function of jaw opening. The displacements of the mandible and TM disc were about 16 mm and 10 mm respectively at mouth opening of 50 mm, maximum rotation of the mandible was 34s. The results of these measurements can be used for clinical diagnostics and also they were used as inputs for the follows finite element analysis (FEA). Second aim of this work was to create stress and strain analysis of TM joint using non-linear FEA. Complex of TM joint consists of mandibular disc, half skull and half mandible during normal jaw opening. The results illustrate the stress distributions in the TMJ during a normal jaw opening.

  4. Imaging patellar complications after knee arthroplasty

    Melloni, Pietro [Unitat de Imatge d' Alta Tecnologia, Centre Diagnostic, Corporacio Parc Tauli, Universitat Autonoma de Barcelona, Sabadell (Barcelona) (Spain)], E-mail:; Valls, Rafael; Veintemillas, Maite [Unitat de Imatge d' Alta Tecnologia, Centre Diagnostic, Corporacio Parc Tauli, Universitat Autonoma de Barcelona, Sabadell (Barcelona) (Spain)


    The purpose of this study is to describe complications affecting the patella in patients with total or partial knee arthroplasty. We respectively analysed plain-film radiographs, as well as ultrasound images when acquired, in a consecutive series of 1272 patients. The mean interval from knee replacement to patellar complications was 5 years and 7 months (range, 5 months to 14 years). The complications described include fracture, instability, dislocation or luxation, necrosis of the patella, infection of the patella, erosion of the patella, patellar impingement on the prosthesis and patellar or quadricipital tendon tear. We discuss the pathological imaging findings in the patella and their differential diagnosis after knee arthroplasty. Patellar complications after knee arthroplasty are uncommon but often potentially serious.

  5. Total Ankle Arthroplasty: A Brief Review

    Roger A. Mann


    Full Text Available Ankle fusion has long been the standard of treatment for end-stage ankle arthritis, and a successful arthroplasty has been a long sought alternative. It is a motion sparing procedure and may greatly reduce the potential for adjacent level degeneration as seen with arthrodesis. The typical candidate for arthroplasty is a healthy low demand patient, although the indications are widening as the success of the procedure has increased. Nevertheless, it is not fail-safe, technical expertise and experience are necessary to achieve a successful result. We have been treating ankle arthritis with the Scandinavian Total Ankle Replacement (STAR ankle replacement prosthesis for over ten years. We believe that arthroplasty will surpass arthrodesis as the standard of care for severe ankle arthritis.

  6. Primary total hip arthroplasty for acetabular fracture

    WANG Zi-ming; SUN Hong-zhen; WANG Ai-min; DU Quan-yin; WU Siyu; ZHAO Yu-feng; TANG Ying


    Objective: To explore the operative indications and operative methods of primary total hip arthroplasty for acetabular fracture and to observe the clinical curative effect.Methods: We retrospectively summarized and analyzed the traumatic conditions, fracture types, complications,operative time, operative techniques, and short-term curative effect of 11 patients( 10 males and 1 female, with a mean age of 42. 4 years ) with acetabular fracture who underwent primary total hip arthroplasty.Results: The patients were followed up for 6-45 months ( mean = 28 months). Their average Harris score of postoperative hip joint was 78.Conclusion: Under strict mastery of indications,patients with acetabular fracture may undergo primary total hip arthroplasty, but stable acetabular components should be made.

  7. Serum Metal Ion Concentrations in Paediatric Patients following Total Knee Arthroplasty Using Megaprostheses

    Jörg Friesenbichler


    Full Text Available The purpose of this study was to determine the concentrations of cobalt, chromium, and molybdenum in the serum of paediatric tumour patients after fixed hinge total knee arthroplasty. Further, these metal ion levels were compared with serum metal ion levels of patients with other orthopaedic devices such as hip and knee prostheses with metal-on-metal or metal-on-polyethylene articulation to find differences between anatomical locations, abrasion characteristics, and bearing surfaces. After an average follow-up of 108 months (range: 67 to 163 of 11 paediatric patients with fixed hinge total knee arthroplasty, the mean concentrations for Co and Cr were significantly increased while Mo was within the limits compared to the upper values from the reference laboratory. Furthermore, these serum concentrations were significantly higher compared to patients with a standard rotating hinge device (P=0.002 and P<0.001 and preoperative controls (P<0.001. On the other hand, the serum levels of patients following MoM THA or rotating hinge arthroplasty using megaprostheses were higher. Therefore, periodic long-term follow-ups are recommended due to the rising concerns about systemic metal ion exposure in the literature. Upon the occurrence of adverse reactions to metal debris the revision of the fixed hinge implant should be considered.

  8. Black hole accretion disc impacts

    Pihajoki, Pauli


    We present an analytic model for computing the luminosity and spectral evolution of flares caused by a supermassive black hole impacting the accretion disc of another supermassive black hole. Our model includes photon diffusion, emission from optically thin regions and relativistic corrections to the observed spectrum and time-scales. We test the observability of the impact scenario with a simulated population of quasars hosting supermassive black hole binaries. The results indicate that for a moderate binary mass ratio of 0.3, and impact distances of 100 primary Schwarzschild radii, the accretion disc impacts can be expected to equal or exceed the host quasar in brightness at observed wavelength {\\lambda} = 510 nm up to z = 0.6. We conclude that accretion disc impacts may function as an independent probe for supermassive black hole binaries. We release the code used for computing the model light curves to the community.

  9. Atomic gas in debris discs

    Hales, Antonio S.; Barlow, M. J.; Crawford, I. A.; Casassus, S.


    We have conducted a search for optical circumstellar absorption lines in the spectra of 16 debris disc host stars. None of the stars in our sample showed signs of emission line activity in either Hα, Ca II or Na I, confirming their more evolved nature. Four stars were found to exhibit narrow absorption features near the cores of the photospheric Ca II and Na I D lines (when Na I D data were available). We analyse the characteristics of these spectral features to determine whether they are of circumstellar or interstellar origins. The strongest evidence for circumstellar gas is seen in the spectrum of HD 110058, which is known to host a debris disc observed close to edge-on. This is consistent with a recent ALMA detection of molecular gas in this debris disc, which shows many similarities to the β Pictoris system.

  10. Coevolution of binaries and circumbinary gaseous discs

    Fleming, David P.; Quinn, Thomas R.


    The recent discoveries of circumbinary planets by Kepler raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary protoplanetary disc and how the disc and binary interact and change as a result. The central binary excites resonances in the surrounding protoplanetary disc which drive evolution in both the binary orbital elements and in the disc. To probe how these interactions impact binary eccentricity and disc structure evolution, N-body smooth particle hydrodynamics simulations of gaseous protoplanetary discs surrounding binaries based on Kepler 38 were run for 104 binary periods for several initial binary eccentricities. We find that nearly circular binaries weakly couple to the disc via a parametric instability and excite disc eccentricity growth. Eccentric binaries strongly couple to the disc causing eccentricity growth for both the disc and binary. Discs around sufficiently eccentric binaries which strongly couple to the disc develop an m = 1 spiral wave launched from the 1:3 eccentric outer Lindblad resonance which corresponds to an alignment of gas particle longitude of periastrons. All systems display binary semimajor axis decay due to dissipation from the viscous disc.

  11. Proprioception and Knee Arthroplasty: A Literature Review.

    Wodowski, Andrew J; Swigler, Colin W; Liu, Hongchao; Nord, Keith M; Toy, Patrick C; Mihalko, William M


    Proprioceptive mechanoreceptors provide neural feedback for position in space and are critical for three-dimensional interaction. Proprioception is decreased with osteoarthritis of the knees, which leads to increased risk of falling. As the prevalence of osteoarthritis increases so does the need for total knee arthroplasty (TKA), and knowing the effect of TKA on proprioception is essential. This article reviews the literature regarding proprioception and its relationship to balance, aging, osteoarthritis, and the effect of TKA on proprioception. Knee arthroplasty involving retention of the cruciate ligaments is also reviewed, as well the evidence of proprioception in the posterior cruciate ligament after TKA.

  12. Total hip arthroplasty after previous fracture surgery.

    Krause, Peter C; Braud, Jared L; Whatley, John M


    Total hip arthroplasty can be a very effective salvage treatment for both failed fracture surgery and hip arthritis that may occur after prior fracture surgery. The rate of complications is significantly increased including especially infection, dislocation, and loosening. Complications are more likely to occur after failed open reduction and internal fixation than after posttraumatic arthritis. Adequately ruling out infection before hip arthroplasty can be difficult. The best predictor of infection is a prior infection. Long-term outcomes can be comparable to outcomes in other conditions if complications are avoided.

  13. Vertebral osteomyelitis without disc involvement

    Kamani, I.; Syed, I.; Saifuddin, A. E-mail:; Green, R.; MacSweeney, F


    Vertebral osteomyelitis is most commonly due to pyogenic or granulomatous infection and typically results in the combined involvement of the intervertebral disc and adjacent vertebral bodies. Non-infective causes include the related conditions of chronic recurrent multifocal osteomyelitis (CRMO) and SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) syndrome. Occasionally, these conditions may present purely within the vertebral body, resulting in various combinations of vertebral marrow oedema and sclerosis, destructive lesions of the vertebral body and pathological vertebral collapse, thus mimicking neoplastic disease. This review illustrates the imaging features of vertebral osteomyelitis without disc involvement, with emphasis on magnetic resonance imaging (MRI) findings.

  14. The Nordic Arthroplasty Register Association

    Havelin, Leif I; Fenstad, Anne M; Salomonsson, Roger


    Background and purpose The possibility of comparing results and of pooling the data has been limited for the Nordic arthroplasty registries, because of different registration systems and questionnaires. We have established a common Nordic database, in order to compare demographics and the results...... collaboration has shown differences between the countries concerning demographics, prosthesis fixation, and survival. The large number of patients in this database significantly widens our horizons for future research....... of total hip replacement surgery between countries. In addition, we plan to study results in patient groups in which the numbers are too small to be studied in the individual countries. Material and methods Primary total hip replacements (THRs) from 1995-2006 were selected for the study. Denmark, Sweden......, and Norway contributed data. A common code set was made and Cox multiple regression, with adjustment for age, sex, and diagnosis was used to calculate prosthesis survival with any revision as endpoint. Results 280,201 operations were included (69,242 from Denmark, 140,821 from Sweden, and 70,138 from Norway...

  15. Dead discs, unstable discs and the stars they surround

    D’Angelo Caroline


    Full Text Available Strong stellar magnetic fields significantly alter the behaviour of surrounding accretion discs. Recent work has demonstrated that at low accretion rates a large amount of mass can remain confined in the disc, contrary to the standard assumption that the magnetic field will expel the disc in an outflow (the “propeller regime”. These “dead discs” often become unstable, causing cycles of accretion onto the central star. Here I present the main predictions of this model, and argue that it provides a good explanation for the peculiar behaviour seen in several accreting sources with strong magnetic fields. I will focus in particular on three accreting millisecond X-ray pulsars: SAX J1808.4-3658, NGC 6440 X-2 and IGR J00291+5934. These sources all show low-frequency quasi-periodic oscillations consistent with a variable accretion rate, as well as unusual outburst patterns that suggest gas is confined in the inner disc regions during quiescence.

  16. Cervical disc prosthesis: 2-year follow-up

    Romero Pinto de Oliveira Bilhar


    Full Text Available OBJECTIVE: To review the medical records of patients who underwent surgery for placement of cervical disc prosthesis after two years of postoperative follow-up, showing the basic epidemiological data, the technical aspects and the incidence of complications.METHODS: Medical records of seven patients who underwent surgery for placement of cervical disc prosthesis were reviewed after two years of follow-up, at the Institute of Orthopedics and Traumatology, Faculty of Medicine, University of São Paulo.RESULTS: The average age of patients participating in this study was 43.86 years. Six patients (85.7% had one level approached while one patient (14.3% had two levels addressed. The level C5-C6 has been approached in one patient (14.3% while the C6-C7 level was addressed in five patients (71.4%. One patient (14.3% had these two levels being addressed, C5-C6 and C6-C7. The mean operative time was 164.29±40 minutes. Three patients were hospitalized for 2 days and four for 3 days making an average of 2.57±0.535 days. Two patients (28.6% underwent a new surgical intervention due to loosening of the prosthesis. The mean follow-up was 28.14±5.178 months (23-35 months.CONCLUSIONS: Although cervical arthroplasty appears to be a safe procedure and present promising results in our study as well as in many other studies, it requires long-term studies.

  17. Photoevaporating transitional discs and molecular cloud cores

    Li, Min; Sui, Ning


    We investigate the evolution of photoevaporating protoplanetary discs including mass influx from molecular cloud cores. We examine the influence of cloud core properties on the formation and evolution of transitional discs. We use one-dimensional thin disc assumption and calculate the evolution of the protoplanetary disc. The effects of X-ray photoevaporation are also included. Our calculations suggest that most discs should experience the transitional disc phase within 10 Myr. The formation time of a gap and its initial location are functions of the properties of the cloud cores. In some circumstances, discs can open two gaps by photoevaporation alone. The two gaps form when the gas in the disc can expand to large radius and if the mass at large radius is sufficiently small. The surface density profile of the disc determines whether the two gaps can form. Since the structure of a disc is determined by the properties of a molecular cloud core, the core properties determine the formation of two gaps in the disc. We further find that even when the photoevaporation rate is reduced to 10 per cent of the standard value, two gaps can still form in the disc. The only difference is that the formation time is delayed.

  18. Radiation of accretion discs: the eclipses

    Schwarzenberg-Czerny, A.


    Light curves have been calculated for eclipses of the accretion disc in a cataclysmic binary. The Roche geometry of the cool component was taken into account and the stellar atmospheres were interpolated to provide the local spectrum of the radiation from the disc. The dependence of the light curve on the parameters of the disc is discussed.

  19. Headache relief after anterior cervical discectomy: post hoc analysis of a randomized investigational device exemption trial: clinical article.

    Schrot, Rudolph J; Mathew, Jesna S; Li, Yueju; Beckett, Laurel; Bae, Hyun W; Kim, Kee D


    The authors analyzed headache relief after anterior cervical discectomy. Headache may be relieved after anterior cervical discectomy, but the mechanism is unknown. If headaches were directly referred from upper cervical pathology, more headache relief would be expected from surgery performed at higher cervical levels. If spinal kinesthetics were the mechanism, then headache relief may differ between arthroplasty and fusion. Headache relief after anterior cervical discectomy was quantified by the operated disc level and by the method of operation (arthroplasty vs arthrodesis). The authors performed a post hoc analysis of an artificial disc trial. Data on headache pain were extracted from the Neck Disability Index (NDI) questionnaire. A total of 260 patients underwent single-level arthroplasty or arthodesis. Preoperatively, 52% reported NDI headache scores of 3 or greater, compared with only 13%-17% postoperatively. The model-based mean NDI headache score at baseline was 2.5 (95% CI 2.3-2.7) and was reduced by 1.3 points after surgery (95% CI 1.2-1.4, p relief. There was no significant difference in headache relief between arthroplasty and arthrodesis. Most patients with symptomatic cervical spondylosis have headache as a preoperative symptom (88%). Anterior cervical discectomy with both arthroplasty and arthrodesis is associated with a durable decrease in headache. Headache relief is not related to the level of operation. The mechanism for headache reduction remains unclear.

  20. Intervertebral disc degeneration in dogs

    Bergknut, Niklas


    Back pain is common in both dogs and humans, and is often associated with intervertebral disc (IVD) degeneration. The IVDs are essential structures of the spine and degeneration can ultimately result in diseases such as IVD herniation or spinal instability. In order to design new treatments halting

  1. Electromagnetic Levitation of a Disc

    Valle, R.; Neves, F.; de Andrade, R., Jr.; Stephan, R. M.


    This paper presents a teaching experiment that explores the levitation of a disc of ferromagnetic material in the presence of the magnetic field produced by a single electromagnet. In comparison to the classical experiment of the levitation of a sphere, the main advantage of the proposed laboratory bench is that the uniform magnetic field…

  2. Optical Disc Applications in Libraries.

    Andre, Pamela Q. J.


    Discusses a variety of library applications of optical disc storage technology, including CD-ROM, digital videodisc, and WORM. Research and development projects at the Library of Congress, National Library of Medicine, and National Agricultural Library are described, products offered by library networks are reviewed, and activities in academic and…

  3. Electromagnetic Levitation of a Disc

    Valle, R.; Neves, F.; de Andrade, R., Jr.; Stephan, R. M.


    This paper presents a teaching experiment that explores the levitation of a disc of ferromagnetic material in the presence of the magnetic field produced by a single electromagnet. In comparison to the classical experiment of the levitation of a sphere, the main advantage of the proposed laboratory bench is that the uniform magnetic field…

  4. Constraints on Slim Accretion Discs

    CAI Zhen-Yi; GU Wei-Min; LU Ju-Fu


    @@ We show that when the gravitational force in the vertical direction is correctly calculated, the well-known Sshaped sequence of thermal equilibrium solutions can be constructed only for small radii of black hole accretion flows, such that slim accretion discs can possibly exist only in the inner regions of these flows.

  5. Magnetorotational instability in protoplanetary discs

    Salmeron, Roberto Aureliano; Salmeron, Raquel; Wardle, Mark


    We investigate the linear growth and vertical structure of the magnetorotational instability (MRI) in weakly ionised, stratified accretion discs. The magnetic field is initially vertical and dust grains are assumed to have settled towards the midplane, so charges are carried by electrons and ions only. Solutions are obtained at representative radial locations from the central protostar for different choices of the initial magnetic field strength, sources of ionisation, and disc surface density. The MRI is active over a wide range of magnetic field strengths and fluid conditions in low conductivity discs. For the minimum-mass solar nebula model, incorporating cosmic ray ionisation, perturbations grow at 1 AU for B < 8 G. For a significant subset of these strengths (0.2 - 5 G), the growth rate is of order the ideal MHD rate (0.75 Omega). Similarly, when cosmic rays are assumed to be excluded from the disc by the winds emitted by the magnetically active protostar, unstable modes grow at this radius for B less...

  6. Recurrent hemarthrosis after total knee arthroplasty.

    Rukavina, Alexander; Kerkhoffs, Gino M M J; Schneider, Philipp; Kuster, Markus S


    This report describes a case of spontaneous recurrent hemarthrosis of the knee that presented 4 weeks after total knee arthroplasty. Femoral arteriography showed a false aneurysm of a branch of the inferior lateral geniculate artery. Therapeutic embolization of the arterial branch was performed using three platinum coils with good clinical result and good knee joint function. Hemarthrosis has not recurred since embolization.

  7. Recurrent hemarthrosis after total knee arthroplasty

    Rukavina, A.; Kerkhoffs, G. M. M. J.; Schneider, P.; Kuster, M S


    This report describes a case of spontaneous recurrent hemarthrosis of the knee that presented 4 weeks after total knee arthroplasty. Femoral arteriography showed a false aneurysm of a branch of the inferior lateral geniculate artery. Therapeutic embolization of the arterial branch was performed using three platinum coils with good clinical result and good knee joint function. Hemarthrosis has not recurred since embolization.

  8. Recurrent hemarthrosis after total knee arthroplasty

    Rukavina, A.; Kerkhoffs, G.M.M.J.; Schneider, P.; Kuster, M.S.


    This report describes a case of spontaneous recurrent hemarthrosis of the knee that presented 4 weeks after total knee arthroplasty. Femoral arteriography showed a false aneurysm of a branch of the inferior lateral geniculate artery. Therapeutic embolization of the arterial branch was performed usin


    Pencho Kosev


    Full Text Available We present our experience with the soft tissue balancing in total hip arthroplasty. Detailed indications, planning and surgical technique are presented. The described procedures are performed on 278 hips for a period of 6 years (2008-2014. We conclude that the outcome of a THA can be improved by balancing the stability, ROM, muscle strength and limb length equality.

  10. Hip and knee arthroplasty: quo vadis?

    Ho, J.; Meis, J.F.G.M.; Nabuurs-Franssen, M.H.; Voss, A.


    Despite of the steady decrease of surgical site infection (SSI) over the last two decades, the incidence of SSI after hip and knee arthroplasty has recently surged. This may be explained by technical changes that may result in an increased risk of SSI, such as the broad implementation of fast track

  11. [Therapy of arthrofibrosis after total knee arthroplasty].

    Gollwitzer, H; Burgkart, R; Diehl, P; Gradinger, R; Bühren, V


    Arthrofibrosis is one of the most common complications after total knee arthroplasty with an overall incidence of approximately 10%. Nevertheless, published data are rare and clinical trials mostly include small and heterogeneous patient series resulting in controversial conclusions. Clinically, arthrofibrosis after knee arthroplasty is defined as (painful) stiffness with scarring and soft tissue proliferation. Differentiation between local (peripatellar) and generalized fibrosis is therapeutically relevant. Histopathology typically shows subsynovial fibrosis with synovial hyperplasia, chronic inflammatory infiltration, and excessive and unregulated proliferation of collagen and fibroblasts. Diagnostic strategies are based on the exclusion of differential causes for painful knee stiffness, and especially the exclusion of low-grade infections represents a diagnostic challenge. Early and intensive physiotherapy combined with sufficient analgesia should be initiated as a basic therapy. The next therapeutic steps for persisting arthrofibrosis include closed manipulation and open arthrolysis. Arthroscopic interventions should be limited to local fibrosis. Revision arthroplasty represents a rescue surgery, often associated with recurrence of fibrosis. Prevention of arthrofibrosis by sufficient analgesia and early physiotherapy remains the best treatment option for painful stiffness after knee arthroplasty.

  12. Dilemmas in Uncemented Total Hip Arthroplasty

    Goosen, J.H.M.


    In this thesis, different aspects that are related to the survivorship and clinical outcome in uncemented total hip arthroplasty are analysed. In Chapter 2, the survival rate, Harris Hip score and radiographic features of a proximally hydroxyapatite coated titanium alloy femoral stem (Bi-Metric, Bio

  13. Fast-track revision knee arthroplasty

    Husted, Henrik; Otte, Niels Kristian Stahl; Kristensen, Billy B;


    Abstract Background and purpose Fast-track surgery has reduced the length of hospital stay (LOS), morbidity, and convalescence in primary hip and knee arthroplasty (TKA). We assessed whether patients undergoing revision TKA for non-septic indications might also benefit from fast-track surgery...

  14. Gait Analysis of Conventional Total Knee Arthroplasty and Bicruciate Stabilized Total Knee Arthroplasty Using a Triaxial Accelerometer

    Saito, Hidetomo; Aizawa, Toshiaki; Miyakoshi, Naohisa; Shimada, Yoichi


    One component of conventional total knee arthroplasty is removal of the anterior cruciate ligament, and the knee after total knee arthroplasty has been said to be a knee with anterior cruciate ligament dysfunction. Bicruciate stabilized total knee arthroplasty is believed to reproduce anterior cruciate ligament function in the implant and provide anterior stability. Conventional total knee arthroplasty was performed on the right knee and bicruciate stabilized total knee arthroplasty was performed on the left knee in the same patient, and a triaxial accelerometer was fitted to both knees after surgery. Gait analysis was then performed and is reported here. The subject was a 78-year-old woman who underwent conventional total knee arthroplasty on her right knee and bicruciate stabilized total knee arthroplasty on her left knee. On the femoral side with bicruciate stabilized total knee arthroplasty, compared to conventional total knee arthroplasty, there was little acceleration in the x-axis direction (anteroposterior direction) in the early swing phase. Bicruciate stabilized total knee arthroplasty may be able to replace anterior cruciate ligament function due to the structure of the implant and proper anteroposterior positioning. PMID:27648328

  15. Medium-term outcomes of artificial disc replacement for severe cervical disc narrowing

    Chao-Hung Yeh


    Conclusions: Acceptable clinical outcome for treatment of severe cervical disc narrowing with cervical disc replacement technique has been performed in current study. Most patients maintained good postoperative mobility and no significant adjacent level degeneration were found. Cervical disc replacement may be applicable in treatment of severe cervical disc narrowing; however, longer follow-ups are required for ensuring the long-term efficacy of cervical disc replacement.

  16. Intervertebral disc calcifications in children.

    Beluffi, G; Fiori, P; Sileo, C


    This study was done to assess the presence of both asymptomatic and symptomatic intervertebral disc calcifications in a large paediatric population. We retrospectively reviewed the radiographs taken during the past 26 years in children (age 0-18 years) undergoing imaging of the spine or of other body segments in which the spine was adequately depicted, to determine possible intervertebral disc calcifications. The following clinical evaluation was extrapolated from the patients' charts: presence of spinal symptoms, history of trauma, suspected or clinically evident scoliosis, suspected or clinically evident syndromes, bone dysplasias, and pre- or postoperative chest or abdominal X-rays. We detected intervertebral disc calcifications in six patients only. Five calcifications were asymptomatic (one newborn baby with Patau syndrome; three patients studied to rule out scoliosis, hypochondroplasia and syndromic traits; one for dyspnoea due to sunflower seeds inhalation). Only one was symptomatic, with acute neck pain. Calcifications varied in number from one in one patient to two to five in the others. Apart from the calcification in the patient with cervical pain, all calcifications were asymptomatic and constituted an incidental finding (particularly those detected at the thoracic level in the patient studied for sunflower-seed inhalation). Calcification shapes were either linear or round. Our series confirms that intervertebral disc calcifications are a rare finding in childhood and should not be a source of concern: symptomatic calcifications tend to regress spontaneously within a short time with or without therapy and immobilisation, whereas asymptomatic calcifications may last for years but disappear before the age of 20 years. Only very few cases, such as those of medullary compression or severe dysphagia due to anterior herniation of cervical discs, may require surgical procedures.

  17. Knee arthroplasty in Denmark, Norway and Sweden

    Bizjajeva, Svetlana; Fenstad, Anne Marie; Furnes, Ove; Lidgren, Lars; Mehnert, Frank; Odgaard, Anders; Pedersen, Alma Becic; Havelin, Leif Ivar


    Background and purpose The number of national arthroplasty registries is increasing. However, the methods of registration, classification, and analysis often differ. Methods We combined data from 3 Nordic knee arthroplasty registers, comparing demographics, methods, and overall results. Primary arthroplasties during the period 1997–2007 were included. Each register produced a dataset of predefined variables, after which the data were combined and descriptive and survival statistics produced. Results The incidence of knee arthroplasty increased in all 3 countries, but most in Denmark. Norway had the lowest number of procedures per hospital—less than half that of Sweden and Denmark. The preference for implant brands varied and only 3 total brands and 1 unicompartmental brand were common in all 3 countries. Use of patellar button for total knee arthroplasty was popular in Denmark (76%) but not in Norway (11%) or Sweden (14%). Uncemented or hybrid fixation of components was also more frequent in Denmark (22%) than in Norway (14%) and Sweden (2%). After total knee arthroplasty for osteoarthritis, the cumulative revision rate (CRR) was lowest in Sweden, with Denmark and Norway having a relative risk (RR) of 1.4 (95% CI: 1.3–1.6) and 1.6 (CI: 1.4–1.7) times higher. The result was similar when only including brands used in more than 200 cases in all 3 countries (AGC, Duracon, and NexGen). After unicompartmental arthroplasty for osteoarthritis, the CRR for all models was also lowest in Sweden, with Denmark and Norway having RRs of 1.7 (CI: 1.4–2.0) and 1.5 (CI: 1.3–1.8), respectively. When only the Oxford implant was analyzed, however, the CRRs were similar and the RRs were 1.2 (CI: 0.9–1.7) and 1.3 (CI: 1.0–1.7). Interpretation We found considerable differences between the 3 countries, with Sweden having a lower revision rate than Denmark and Norway. Further classification and standardization work is needed to permit more elaborate studies. PMID:20180723

  18. Poor 10-year survivorship of hip resurfacing arthroplasty

    Seppänen, Matti; Karvonen, Mikko; Virolainen, Petri; Remes, Ville; Pulkkinen, Pekka; Eskelinen, Antti; Liukas, Antti; Mäkelä, Keijo T


    Background and purpose In a previous registry report, short-term implant survival of hip resurfacing arthroplasty (HRA) in Finland was found to be comparable to that of total hip arthroplasty (THA). Since then, it has become evident that adverse reactions to metal debris (ARMDs) may also be associated with HRA, not only with large-diameter head metal-on-metal THA. The aim of the study was to assess medium- to long-term survivorship of HRA based on the Finnish Arthroplasty Register (FAR). Patients and methods 5,068 HRAs performed during the period 2001–2013 in Finland were included. Kaplan-Meier survival analysis was used to calculate survival probabilities and their 95% confidence intervals (CIs). Cox multiple regression, with adjustment for age, sex, diagnosis, femoral head size, and hospital volume was used to analyze implant survival of HRA devices with revision for any reason as endpoint. The reference group consisted of 6,485 uncemented Vision/Bimetric and ABG II THAs performed in Finland over the same time period. Results The 8-year survival, with any revision as an endpoint, was 93% (CI: 92–94) for Birmingham Hip Resurfacing (BHR), 86% (CI: 78–94) for Corin, 91% (CI: 89–94) for ReCap, 92% (CI: 89–96) for Durom, and was 72% (CI: 69–76) for the Articular Surface Replacement (ASR). The 10-year survival, with any revision as an endpoint, for reference THAs was 92% (CI: 91–92) and for all HRAs it was 86% (CI: 84–87%). Female HRA patients had about twice the revision risk of male patients. ASR had an inferior outcome: the revision risk was 4-fold higher than for BHR, the reference implant. Interpretation The 10-year implant survival of HRAs is 86% in Finland. According to new recommendations from NICE (The National Institute for Health and Care Excellence), an HRA/THA should have a revision rate of 5% or less at 10 years. None of the HRAs studied achieved this goal. PMID:27759474

  19. Planetary migration in weakly magnetized turbulent discs

    Baruteau, C.; Fromang, S.; Nelson, R. P.; Masset, F.


    In laminar viscous disc models, the migration of protoplanets embedded in their nascent protoplanetary discs may be directed inwards or outwards, depending on the relative magnitude of the Lindblad and corotation torques. The long-term evolution of the corotation torque is intimately related to diffusion processes inside the planet's horseshoe region. This communication examines the properties of the corotation torque in discs where magnetohydrodynamic (MHD) turbulence develops as a result of the magnetorotational instability (MRI), considering a weak initial toroidal magnetic field. We show that the differential Lindblad torque takes very similar values in MHD turbulent and laminar viscous discs, and there exists an unsaturated corotation torque in MHD turbulent discs.

  20. Radiation from optically thin accretion discs

    Tylenda, R. (Polska Akademia Nauk, Torun. Pracownia Astrofizyki)


    Accretion discs in cataclysmic variables with low rates of mass transfer, M < or approx. 10/sup 16/g s/sup -1/, have outer regions optically thin in continuum. A simple approach that allows one to calculate the radiation spectra from such discs is presented. A great number of disc models has been obtained in order to study the influence of various parameters (accretion rate, outer radius of the disc, inclination angle, mass of the accreting degenerate dwarf, viscosity parameter) of discs on the outgoing continuous spectra, emission lines and the UBV colours.

  1. Computer-assisted navigation in knee arthroplasty: a critical appraisal.

    Venkatesan, Muralidharan; Mahadevan, Devendra; Ashford, Robert U


    The purpose of this review was to appraise the use of computer-assisted navigation in total knee arthroplasty and to assess whether this technology has improved clinical outcomes. Studies were identified through searches in MEDLINE, Embase, and PubMed. Numerous studies have shown improved leg and component alignment using navigation systems. However, the better alignment achieved in navigated knee arthroplasty has not been shown to lead to better clinical outcomes. Navigated knee arthroplasty had lower calculated blood loss and lower incidence of fat embolism compared with conventional knee arthroplasty using intramedullary jigs. It may be most valued when dealing with complex knee deformities, revision surgery, or minimally invasive surgery. Navigated knee arthroplasty, however, is only cost-effective in centers with a high volume of joint replacements. Overall, computer-assisted navigated knee arthroplasty provides some advantages over conventional surgery, but its clinical benefits to date are unclear and remain to be defined on a larger scale.

  2. The artificial disc: theory, design and materials.

    Bao, Q B; McCullen, G M; Higham, P A; Dumbleton, J H; Yuan, H A


    Low back pain is one of the most common medical conditions in the Western world. Disc degeneration, an inevitable process of aging, of variable rate and degree, is one of the major causes of low back pain. Currently, there are two major surgical interventions for treating conditions related to the degenerative disc: discectomy and fusion. Although discectomy and fusion produce a relatively good short-term clinical result in relieving pain, both these surgical treatments alter the biomechanics of the spine, possibly leading to further degeneration of the surrounding tissues and the discs at adjacent levels. Over the past 35 years, a tremendous effort has been made to develop an artificial disc to replace the degenerated disc. The goal is the restoration of the natural biomechanics of the segment after disc excision, thus relieving pain and preventing further degeneration at adjacent segments. However, the artificial disc faces a complex biomechanical environment which makes replication of the biomechanics difficult and long-term survival challenging to designs and materials. The purpose of this article is to examine the factors of importance in designing a disc replacement. Topics covered include the structure and function of the natural disc, the changes that occur with disc degeneration and existing methods of treatment for the degenerative spine. The progress in achieving a functional, long-lasting disc replacement is outlined.

  3. Design rationale and biomechanics of Maverick Total Disc arthroplasty with early clinical results.

    Mathews, Hallett H; Lehuec, Jean-Charles; Friesem, Tai; Zdeblick, Thomas; Eisermann, Lukas


    This paper reviews the design criteria, biomechanical and biological (wear and safety) testing of this chrome cobalt metal-on-metal, ball and socket design prosthesis. The surgical technique and early clinical results of the initial implantations are also reviewed. Initial results of 7 Maverick implantations showed all 7 patients attaining a 15 point Oswestry improvement within 3 months after implantation. This early result in a small sample is significantly quicker in recovery and improvement when compared to the historical control of the LT cage with Infuse IDE study. Longer term results and more careful study are needed of this interesting and optimistic finding.

  4. The properties of external accretion discs

    Pringle, J.E. (Space Telescope Science Inst., Baltimore, MD (USA))


    The properties of external accretion discs (discs with a central source of angular momentum) are explored both analytically and numerically. An illustrative example of the effect of a disc of material around a binary star on the stellar separation is considered. We consider a Greens-function-type solution in which an initial ring of matter is put in orbit around the central binary. We find that the solution splits temporally into three parts. First, the disc evolves as a standard accretion disc unaware of the inner boundary condition. Secondly, the disc interacts with the inner boundary and changes its character to become, thirdly, an outflowing disc which is propelled outwards by the source of angular momentum at the centre. (author).

  5. Twisted accretion discs: Pt. 5; Viscous evolution

    Kumar, S. (Max-Planck-Institut fuer Physik und Astrophysik, Garching (Germany, F.R.). Inst. fuer Astrophysik)


    The time-dependence of accretion discs with orbits tilted out of the symmetry plane is studied. The effects of mass inflow modulation, and tilt variation at the disc outer edge, are examined for both circumbinary discs and for discs around compact objects. The appendices extend the numerical work to some analytic examples of tilt diffusion and external forcing effects. It is also shown that the disc must not be treated as a rigid tilted object if global angular momentum is to be conserved. These results are relevant to the problem of long-term periodicities of the light curves in Her X1 and {epsilon} Aur, the S-type symmetry of radio jets, warped gas discs in galaxies and polar rings in Neptune. Twisted discs may also arise in star-forming regions. (author).

  6. Three-level cervical disc herniation

    St. Iencean Andrei


    Full Text Available Multilevel cervical degenerative disc disease is well known in the cervical spine pathology, with radicular syndromes or cervical myelopathy. One or two level cervical herniated disc is common in adult and multilevel cervical degenerative disc herniation is common in the elderly, with spinal stenosis, and have the same cause: the gradual degeneration of the disc. We report the case of a patient with two level cervical disc herniation (C4 – C5 and C5 – C6 treated by anterior cervical microdiscectomy both levels and fusion at C5 – C6; after five years the patient returned with left C7 radiculopathy and MRI provided the image of a left C6 – C7 disc herniation, he underwent an anterior microsurgical discectomy with rapid relief of symptoms. Three-level cervical herniated disc are rare in adults, and the anterior microdiscectomy with or without fusion solve this pathology.

  7. Two-level total disc replacement with Mobi-C(r over 3-years

    Reginald Davis


    Full Text Available Objective: To evaluate the safety and effectiveness of two-level total disc replacement (TDR using a Mobi-C(r Cervical Artificial Disc at the 36 month follow-up. Methods: a Prospective, randomized, controlled, multicenter clinical trial of an artificial cervical disc (Mobi-C(r Cervical Artificial Disc was conducted under the Investigational Device Exemptions (IDE and the U.S. Food & Drug Administration (FDA regulations. A total of 339 patients with degenerative disc disease were enrolled to receive either two-level treatment with TDR, or a two-level anterior cervical discectomy and fusion (ACDF as control. The 234 TDR patients and 105 ACDF patients were followed up at regular time points for three years after surgery. Results: At 36 months, both groups demonstrated an improvement in clinical outcome measures and a comparable safety profile. NDI scores, SF-12 PCS scores, patient satisfaction, and overall success indicated greater statistically significant improvement from baseline for the TDR group, in comparison to the ACDF group. The TDR patients experienced lower subsequent surgery rates and a lower rate of adjacent segment degeneration. On average, the TDR patients maintained segmental range of motion through 36 months with no device failure. Conclusion: Results at three-years support TDR as a safe, effective and statistically superior alternative to ACDF for the treatment of degenerative disc disease at two contiguous cervical levels.

  8. Enhancing Postoperative Rehabilitation Following Knee Arthroplasty Using a New Cryotherapy Product

    Pavlou, Paul; Barrett, Matthew; Thurston, Benjamin; Garrett, Simon


    To compare a novel cooling product, Physicool (P, Physicool Ltd, London, England, UK) with a well-established cryotherapy system, Cryocuff (C, Aircast, DJO Global, Vista, California, USA) using pain scores, range of movement (ROM), and cost as outcome measures in the early phase following total knee arthroplasty. We prospectively studied 90 consecutive patients undergoing unilateral total knee arthroplasty by a single surgeon. Following exclusions, 40 patients were recruited to each group. Visual analogue scale (VAS) for pain and ROM before and after application of cooling device was recorded at 24 and 48 hours after surgery. The cost of treatment per patient was also calculated. The VAS were significantly reduced in P on day 1 postsurgery (p = 0.013) and day 2 (p = 0.001) compared to C. A significant increase in ROM was recorded in P at 24 hours (p = 0.004) and at 48 hours (p = 0.009) postsurgery compared to C. The cost benefit of using P over C was approximately £25 per patient. The Physicool system is a safe and effective cooling method for improving pain and ROM in the early postoperative phase following total knee arthroplasty. Furthermore, it offers substantial cost savings. PMID:26623168

  9. Anteroposterior glide versus rotating platform low contact stress (LCS knee arthroplasty: a randomised controlled trial

    Wynn-Jones Charles


    Full Text Available Abstract Background Fifty thousand knee replacements are performed annually in the UK at an estimated cost of £150 million. Post-operative improvement depends on a number of factors including implant design and patient associated factors. To our knowledge there are no published study's comparing the results of AP glide and rotating platform designs of LCS knee arthroplasty. Therefore we feel that a study is required to investigate and compare the effects of two types of LCS total knee arthroplasty on joint proprioception and range of motion. Methods/Design Patients will be randomised to receive either a LCS AP glide or Rotating platform prosthesis. Clinical scores (Oxford knee score, American knee society score, EuroQol, range of motion and proprioception will be assessed prior to and at 3,6, 12 and 24 months after the operation. Proprioception will be assessed in terms of absolute error angle (mean difference between the target angle and the response angle. Knee angles will be measured in degrees using an electromagnetic tracking device, Polhemus 3Space Fastrak that detects positions of sensors placed on the test limb. Student's t-test will be used to compare the mean of two groups. Discussion Evidence is lacking concerning the best prosthesis to use for patients undergoing total knee replacement. This pragmatic randomised trial will test the null hypothesis that anteroposterior glide LCS knee arthroplasty does not result in better post operative knee motion and proprioception as compared to rotating platform LCS knee. Trial Registration ISRCTN52943804

  10. Total hip arthroplasty using TRI-LOCK® DePuy bone preservation femoral stem: our experience.

    Sperati, G; Ceri, L


    In this study we report our 3-years experience (from January 2010 to December 2013) of 101 total hip arthroplasties using Tri-Lock® DePuy bone preservation femoral stem, all performed in our clinic. 101 patients (F54-M47; median age around 69 yrs, range 42-84 yrs). 51 arthroplasties were implanted on the right side whereas 50 on the left side. The average follow-up was 27,3 months. All the arthroplasties were coupled with Pinnacle® polyethylene acetabular cup system; 98 prostheses were implanted cementless whereas cement was used in 3 cases. The Tri-Lock® femoral stem allows both soft tissues and bone stock preservation, leading to greater trochanter maintenance, less spongy bone removal and distal cavity bone tissue conservation. In our experience, we were able to implant the Tri-Lock® femoral stem even in osteoporotic and overweight patients using Gription® porous coating. This allowed for commencing an intensive rehabilitation program with stable load from the following day, without observing any early complications or loosening. According to us, this device is solid and safe, providing remarkable sparing of both soft tissues and bone stock.

  11. Unexpected wear of an unicompartimental knee arthroplasty in oxidized zirconium.

    Luyet, Anais; Fischer, Jean-François; Jolles, Brigitte M; Lunebourg, Alexandre


    Unicompartimental knee arthroplasty is a successful procedure for the treatment of localized osteoarthritis to one compartment of the knee with good long-term results. However, several modes of failure of unicompartimental knee arthroplasty have been described, namely aseptic or septic loosening, progression of disease, wear, and instability. Metallosis after unicompartimental knee arthroplasty is rarely reported and is most often related with polyethylene wear or break. We report on a case of rapid failure of unicompartimental knee arthroplasty in oxidized zirconium associated with metallosis secondary to the dislocation of the polyethylene.

  12. Total joint arthroplasties: current concepts of patient outcomes after surgery.

    Jones, C Allyson; Beaupre, Lauren A; Johnston, D W C; Suarez-Almazor, Maria E


    Total hip and knee arthroplasties are effective surgical interventions for relieving hip pain and improving physical function caused by arthritis. Although the majority of patients substantially improve, not all report gains or are satisfied after receiving total joint arthroplasty. This article reviews the literature on patient outcomes after total hip and knee arthroplasties for osteoarthritis, and the evidence pertaining to factors that affect these patient-centered outcomes. Mounting evidence suggests that no single patient-related or perioperative factor clearly predicts the amount of pain relief or functional improvement that will occur following total hip or knee arthroplasty.

  13. Enlarged transacromial superior approach with reverse shoulder arthroplasty for fractures

    Alexandre Poignard


    Full Text Available The authors describe a step-by-step technique for reverse total shoulder arthroplasty using arthrotomy via the enlarged transacromial superior approach. This technique seems ideal for reinsertion of the tuberosities and to ensure adequate postoperative tensional balance of the infraspinatus and the subscapularis, which is critical for the rotator cuffs to function properly and to achieve optimal arthroplasty stability. Reviewing these different steps helps understanding each rotator cuff individual component's contribution to achieve optimal arthroplasty stability and external rotation with a reverse shoulder arthroplasty.

  14. Centrifugally exhausting discs: an inverse process of disc-like accretion

    Kaburaki, O.


    A disc-like mass-loss process from rapidly rotating, highly magnetized objects is investigated. Such a disc may be considered as an inverse-type of magnetized accretion discs. The disc plasma flows out radially with the Alfven velocity while it rotates, in the main part of the disc, with Keplerian velocity. The magnetic stress transfers angular momentum from the central spinner to the disc. A considerable fraction of the rotational energy extracted in association with the angular momentum is liberated in the disc through the (effective) Joule dissipation. An almost self-consistent set of analytic expressions is proposed as a solution to the steady-state, resistive MHD equations which are fairly simplified by the assumption of thin disc. The possibility of finding such discs around young neutron stars is briefly discussed with reference to SN 1987A.

  15. Parameters that effect spine biomechanics following cervical disc replacement.

    Goel, Vijay K; Faizan, Ahmad; Palepu, Vivek; Bhattacharya, Sanghita


    Total disc replacement (TDR) is expected to provide a more physiologic alternative to fusion. However, long-term clinical data proving the efficacy of the implants is lacking. Limited clinical data suggest somewhat of a disagreement between the in vitro biomechanical studies and in vivo assessments. This conceptual paper presents the potential biomechanical challenges affecting the TDR that should be addressed with a hope to improve the clinical outcomes and our understanding of the devices. Appropriate literature and our own research findings comparing the biomechanics of different disc designs are presented to highlight the need for additional investigations. The biomechanical effects of various surgical procedures are analyzed, reiterating the importance of parameters like preserving uncinate processes, disc placement and its orientation within the cervical spine. Moreover, the need for a 360° dynamic system for disc recipients who may experience whiplash injuries is explored. Probabilistic studies as performed already in the lumbar spine may explore high risk combinations of different parameters and explain the differences between "standard" biomechanical investigations and clinical studies. Development of a patient specific optimized finite element model that takes muscle forces into consideration may help resolve the discrepancies between biomechanics of TDR and the clinical studies. Factors affecting long-term performance such as bone remodeling, subsidence, and wear are elaborated. In vivo assessment of segmental spine motion has been, and continues to be, a challenge. In general, clinical studies while reporting the data have placed lesser emphasis on kinematics following intervertebral disc replacements. Evaluation of in vivo kinematics following TDR to analyze the quality and quantity of motion using stereoradiogrammetric technique may be needed.

  16. Grain charging in protoplanetary discs

    Ilgner, Martin


    Recent work identified a growth barrier for dust coagulation that originates in the electric repulsion between colliding particles. Depending on its charge state, dust material may have the potential to control key processes towards planet formation such as MHD (magnetohydrodynamic) turbulence and grain growth which are coupled in a two-way process. We quantify the grain charging at different stages of disc evolution and differentiate between two very extreme cases: compact spherical grains and aggregates with fractal dimension D_f = 2. Applying a simple chemical network that accounts for collisional charging of grains, we provide a semi-analytical solution. This allowed us to calculate the equilibrium population of grain charges and the ionisation fraction efficiently. The grain charging was evaluated for different dynamical environments ranging from static to non-stationary disc configurations. The results show that the adsorption/desorption of neutral gas-phase heavy metals, such as magnesium, effects the ...

  17. Superhumps, resonances and accretion discs

    Whitehurst, R.; King, A. (Leicester Univ. (UK). Dept. of Astronomy)


    The structure of accretion discs within binary systems is shown to be influenced by the excitation of resonances within the disc. Of particular importance is that near the 3:1 commensurability with the stars' orbit. This can be used to explain the superhump phenomenon of SU Ursae Majoris dwarf novae in superoutburst. This resonance can only appear for mass ratios which satisfy M{sub 2}/M{sub 1} < {approx equal} 0.25-0.33: for larger mass ratios the available resonances are weaker and of the wrong form to produce the superhump phenomenon. The mass-transfer stream is shown to be an important contributor to the growth rate of the resonance. (author).

  18. Insertion of PCB to treat traumatic cervical intervertebral disc herniation

    马远征; 隰建成; 陈兴; 关长勇; 全长彬


    Objective: To evaluate the clinical effect of PCB (a new anterior cervical instrumental system combining an intradiscal cage with an integrated plate) in treating traumatic cervical intervertebral disc herniation. Methods: Anterior decompression and PCB internal fixation were used in 22 patients with traumatic cervical intervertebral disc herniation. They were followed up from 3 to 16 months and analyzed by symptom and image data. Among them, 16 patients underwent fixation at one level and 6 patients at two levels. Results: This technique did not cause intraoperative complications. After surgery no screw backout or device failure was found. Based on the JOA grade, 20 patients improved clinically and 2 gently because of serious cervical stenosis. The general excellent rate was 90.9%. Conclusions: PCB internal fixation is stable. Morbidity of donor and acceptor sites is less. No collars are needed after surgery.

  19. Insertion of PCBto treat traumatic cervical intervertebral disc herniation

    马远征; 陈兴; 等


    Objective:To evaluate the clinical effect of PCB(a new anterior cervical instrumental system combining an intradiscal cage with an integrated plate)in treating taunatic cervical intervertebral disc herniation.Methods:Anterior decompression and PCB internal fixation were used in 22patients with traumatic cervical intervertebral disc herniation.They were followed up from3to16months and analyzed by symptom and imape data.Among them,16 patients underwent fixation at one level and 6patients at two levels.Results:This technique did not cause intraoperative complications.After surgery on screw backout or device failure was found.Based on the JOAgrade,20 patients improved clinically and 2gently because of serious cervical stenosis.The general excellent rate was90.9%.Conclusions:PCB internal fixation is stable.Morbidity of donor and acceptor sites is less.No collars are needed after surgery.

  20. Eclipse mapping of accretion discs

    Baptista, Raymundo


    The eclipse mapping method is an inversion technique that makes use of the information contained in eclipse light curves to probe the structure, the spectrum and the time evolution of accretion discs. In this review I present the basics of the method and discuss its different implementations. I summarize the most important results obtained to date and discuss how they have helped to improve our understanding of accretion physics, from testing the theoretical radial brightness temperature dist...

  1. Disc distraction shows evidence of regenerative potential in degenerated intervertebral discs as evaluated by protein expression, magnetic resonance imaging, and messenger ribonucleic acid expression analysis.

    Guehring, Thorsten; Omlor, Georg W; Lorenz, Helga; Engelleiter, Karl; Richter, Wiltrud; Carstens, Claus; Kroeber, Markus


    An animal model of degeneration was used to determine the effects of disc distraction, and was evaluated with magnetic resonance imaging (MRI) as well as gene and protein expression levels. To investigate gene expression and MRI effects of distraction. Disc degeneration can result from hyper-physiologic loading. Distracted discs with degeneration showed histologic signs of tissue recovery. There were 18 rabbits that underwent 28 days of compression (200 N) to induce moderate disc degeneration followed by 28 days of distraction (120 N; attached and loaded distraction device) or sham distraction (attached but unloaded distraction device). Comparison was performed with 56 days of compressed discs without distraction. Quantitative outcome measures were MRI signal intensity and gene expression analysis to determine: messenger ribonucleic acid levels for extracellular matrix genes, including collagen 1, collagen 2, biglycan, decorin, aggrecan, fibromodulin, and osteonectin; and matrix-regulative genes, including matrix metalloproteinase-13, tissue-inhibitor of matrix metalloproteinase-1, and bone morphogenetic protein (BMP)-2. Immunohistology was performed for collagen 2 and BMP-2 to label cells semiquantitatively by staining of the cell-surrounding matrix. A total of 28 days of compression decreased signal intensity. Distraction over the same period reestablished physiologic signal intensity, however, a persistent reduction was found in sham distraction. Distraction resulted in gene expression up-regulation of collagen 1 (5.4-fold), collagen 2 (5.5-fold), biglycan (7.7-fold), and decorin (3.4-fold), while expression of fibromodulin (0.16-fold), tissue-inhibitor of matrix metalloproteinase-1 (0.05-fold), and BMP-2 (0.15-fold) was decreased, as compared with 56 days compression. Distracted discs showed more BMP-2 (19.67 vs. 3.67 in 56 days compression) and collagen 2 (18.67 vs. 11.33 in 56 days compression) positive cells per field. Distraction results in disc rehydration

  2. The dispersal of protoplanetary discs

    Ercolano Barbara


    Full Text Available Protoplanetary discs are a natural consequence of the star formation process and as such are ubiquitous around low-mass stars. They are fundamental to planet formation as they hold the reservoir of material from which planets form. Their evolution and final dispersal and the timescales that regulate these process are therefore of particular interest. In this contribution I will review the observational evidence for the dispersal of discs being dominated by two timescales and for the final dispersal to occur quickly and from the inside out. I will discuss the current theoretical models, including X-ray photoevaporation, showing that the latter provides a natural explanation to the observed behaviour and review supporting and contrasting evidence. I will finally introduce a new mechanism based on the interaction between planet formation and photoevaporation that may explain a particular class of transition discs with large inner holes and high accretion rates that are problematic for photoevaporation models and planet formation models alone.

  3. Utilization rates of knee-arthroplasty in OECD countries.

    Pabinger, C; Lothaller, H; Geissler, A


    The number of knee arthroplasties and the prevalence of obesity are increasing exponentially. To date there have been no published reviews on utilization rates of knee arthroplasty in OECD countries. We analysed economic, medical and population data relating to knee arthroplasty surgeries performed in OECD countries. Gross domestic product (GDP), health expenditures, obesity prevalence, knee arthroplasty utilization rates and growth in knee arthroplasty rates per 100,000 population were assessed for total population, for patients aged 65 years and over, and patients aged 64 years and younger. Obesity prevalence and utilization of knee arthroplasty have increased significantly in the past. The mean utilization rate of knee arthroplasty was 150 (22-235) cases per 100,000 total population in 2011. The strongest annual increase (7%) occurred in patients 64 years and under. Differences between individual countries can be explained by economic and medical patterns, with countries with higher medical expenditures and obesity prevalence having significantly higher utilization rates. Countries with lower utilization rates have significantly higher growth in utilization rates. The future demand for knee prostheses will increase x-fold by 2030, with exact rates dependant upon economic, social and medical factors. We observed a 10-fold variation in the utilization of knee arthroplasty among OECD countries. A significant and strong correlation of GDP, health expenditures and obesity prevalence with utilization of knee arthroplasty was found. Patients aged 64 years and younger show a two-fold higher growth rate in knee arthroplasty compared to the older population. This trend could result in a four-fold demand for knee arthroplasty in OECD countries by 2030. Copyright © 2015 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  4. Cementless two-stage exchange arthroplasty for infection after total hip arthroplasty.

    Masri, Bassam A; Panagiotopoulos, Kostas P; Greidanus, Nelson V; Garbuz, Donald S; Duncan, Clive P


    We retrospectively reviewed all patients at one center with an infected total hip arthroplasty treated with 2-stage revision using cementless components for the second stage and the PROSTALAC articulated spacer at the first stage. Twenty-nine patients were reviewed and followed for at least 2 years postoperatively. An isolated Staphylococcus species was cultured in 76% (22/29) of patients. Three (10.3%) of 29 patients had recurrent infection at the site of the prosthesis. One of the 3 patients ultimately underwent a Girdlestone arthroplasty. Another patient was managed with irrigation and debridement, whereas the final patient was treated with intravenous antibiotics alone. Treatment of infection at the site of a hip arthroplasty with 2-stage revision using cementless components and an articulated spacer yields recurrence rates similar to revisions where at least one of the components at the second stage is fixed with antibiotic-loaded cement.

  5. Thromboembolism prophylaxis practices in orthopaedic arthroplasty patients.

    Cawley, D


    Thromboembolic events are a post-operative complication of arthroplasty surgery for up to 3 months. The incidence however, is not fully known. Some form of prophylaxis should be provided to all arthroplasty patients. Clinicians are wary of side effects, compliance profile and the associated cost. The objective of this study is to investigate practice patterns and their relevance to 3 risk groups. Ninety questionnaires were sent to orthopaedic surgeons with 3 hypothetical clinical scenarios and 10 prophylaxis regimes for thromboembolism across different risk groups. The response rate was 81\\/90 (90%). The most popular options in all 3 cases were early mobilisation, thrombo-embolism deterrant (TED) stockings and low molecular weight heparin (LMWH) (51\\/81, 62% of all cases). An inconsistent relationship exists between preferred practice and relevant guidelines. Preferred practice does not correlate with each level of risk.

  6. Cost Analysis in Shoulder Arthroplasty Surgery

    Matthew J. Teusink


    Full Text Available Cost in shoulder surgery has taken on a new focus with passage of the Patient Protection and Affordable Care Act. As part of this law, there is a provision for Accountable Care Organizations (ACOs and the bundled payment initiative. In this model, one entity would receive a single payment for an episode of care and distribute funds to all other parties involved. Given its reproducible nature, shoulder arthroplasty is ideally situated to become a model for an episode of care. Currently, there is little research into cost in shoulder arthroplasty surgery. The current analyses do not provide surgeons with a method for determining the cost and outcomes of their interventions, which is necessary to the success of bundled payment. Surgeons are ideally positioned to become leaders in ACOs, but in order for them to do so a methodology must be developed where accurate costs and outcomes can be determined for the episode of care.

  7. Heterotopic bone formation following total shoulder arthroplasty

    Kjaersgaard-Andersen, P.; Frich, Lars Henrik; Sjøbjerg, J.O.


    The incidence and location of heterotopic bone formation following total shoulder arthroplasty were evaluated in 58 Neer Mark-II total shoulder replacements. One year after surgery, 45% had developed some ectopic ossification. In six shoulders (10%) the ossifications roentgenographically bridged...... the glenohumeral and/or the glenoacromial space. There was no correlation between shoulder pain and the development of ossification. Shoulders with grade III heterotopic bone formation had a limited range of active elevation compared with shoulders without or with only a milder lesion. Men and patients...... with osteoarthritis of the shoulder joint were significantly disposed to the development of heterotopic bone. Heterotopic bone formation following total shoulder arthroplasty is frequent, but disabling heterotopic ossifications seem to be rare....

  8. Principles of management and results of treating the fractured femur during and after total hip arthroplasty.

    Greidanus, Nelson V; Mitchell, Philip A; Masri, Bassam A; Garbuz, Donald S; Duncan, Clive P


    The management of fractures of the femur during and after total hip arthroplasty can be difficult, and treatment can be fraught with complications. The ideal scenario would be one in which these fractures are prevented. It is important that the surgeon has a through understanding of the principles of managing these fractures and has access to a variety of fixation and prosthetic devices and allograft bone when necessary in order to provide the best treatment. Because periprosthetic fractures range from the very simple (requiring no surgical intervention) to the complex (requiring major revision), a classification system of these fractures aids in understanding both the principles of management and results of treatment.

  9. New concepts in revision total knee arthroplasty.

    Vince, Kelly G; Droll, Kurt; Chivas, Dan


    Revision knee arthroplasty should be regarded as a discipline separate from primary surgery. A disciplined approach to diagnosis is mandatory in which the following categories for failure are useful: (a) sepsis, (b) extensor mechanism rupture, (c) stiffness, (d) instability, (e) periprosthetic fracture, (f) aseptic loosening and osteolysis, (g) patellar complications and malrotation, (h) component breakage, and (i) no diagnosis. In the event of no coherent explanation for pain and disability, the possibilities of chronic regional pain syndrome, hip or spine pathology, and inability of current technology to meet patient expectations should be considered and revision surgery should be avoided. Revision arthroplasty cannot be performed as if it were a primary procedure and indeed will be eight (or more) different surgeries depending on the cause of failure. Though perhaps counterintuitive, there is a logical rationale and empirical evidence to support complete revision in virtually every case. In general, revision implant systems are required. The early dependence on the "joint line" is inadequate, failing as it does to recognize that the level of the articulation is a three-dimensional concept and not simply a "line." The key to revision surgery technique is that the flexion gap is determined by femoral component size and the extension gap by proximal distal component position. Accordingly, a general technical pathway of three steps can be recommended: 1) tibial platform; 2) stabilization of the knee in flexion with (a) femoral component rotation and (b) size selected with evaluation of (c) patellar height as an indication of "joint line" in flexion only; and 3) stabilization of the knee in extension, an automatic step. Stem extensions improve fixation and, if they engage the diaphysis, may be used as a guide for positioning. Porous metals designed as augments for bone defects may prove more important as "modular fixation interfaces." It is postulated that with the

  10. Postoperative pyrexia after arthroplasty - when to panic ?

    Agarwala Sanjay; Jain Deepak; Bhagwat Abhijit


    Background: Success of arthroplasty is contingent on a clear understanding of the potential complications. Today with improved methods of sepsis control, incidence of joint sepsis has dropped to less than 2%. Despite this fever is still common in the early post-operative period. Methods: We reviewed 184 consecutive hip and knee replacement surgeries for incidence and clinical significance of post-operative fever. The cases were followed up for a period of over 3 to 5 years. Temperat...

  11. Proximal humeral fractures treated with arthroplasty

    QIAN Qi-rong; WU Hai-shan; ZHOU Wei-jiang; LI Xiao-hua; WU Yu-li


    Objective: To explore arthroplasty in treating 3- and 4-part fractures of the proximal humerus.Methods: A total of 132 patients with proximal humeral fractures were treated in our hospital from July 1997 to February 2003. According to Neer's classification, the fractures of 45 patients (14 males and 31 females, aged 31-78 years, 56.1 years±7.8 years on an average) belonged to 3- or 4-part fractures (10 patients with 4-part fracture and 35 with 3-part comminuted fracture) and they were treated with shoulder joint arthroplasty. Unipolar prosthesis replacement of the head of humerus was made in 28 cases, while bipolar prosthesis replacement in 2 cases and total shoulder joint replacement in 15 cases. Results: During the follow-up period (range: 12-72 months, mean: 37.3 months±4.1 months), among the 45 patients who suffered from fractures of the proximal humerus and underwent arthroplasty surgery, 44 patients (97.8%) had no postoperative pain and were satisfied with the active range of motion and with the whole treatment results. And radiography showed that the prostheses were at their good position. One patient had postoperative pain because he had so narrow medullary cavity that the humeral prosthesis could not be put deeply enough and the prosthesis head was a little higher over the anatomic level. He did not have good postoperative active range of motion, either. Then he received a review surgery and got satisfied results. Temporary shoulder stiffness was observed in one patient. Manual release of these adhesions improved the shoulder function. No evidence of nonunion of the fracture segments around the humeral prosthesis stem was found. Conclusions: Shoulder arthroplasty is a dependable method to restore the comfort and function of the should joints of the patients with 3- or 4-part fractures of the proximal humerus.

  12. Dilemmas in Uncemented Total Hip Arthroplasty

    Goosen, J. H. M.


    In this thesis, different aspects that are related to the survivorship and clinical outcome in uncemented total hip arthroplasty are analysed. In Chapter 2, the survival rate, Harris Hip score and radiographic features of a proximally hydroxyapatite coated titanium alloy femoral stem (Bi-Metric, Biomet) was evaluated. In conclusion, at an average follow-up of 8 years, this proximally HA-coated femoral component showed favorable clinical and radiological outcome and excellent survivorship. In ...

  13. Imaging of hip arthroplasty; Bildgebung bei Hueftprothesen

    Breitenseher, M.J. [Abteilung fuer Osteologie, Universitaetsklinik fuer Radiodiagnostik, Wien (Austria); Klinische Abteilung fuer Radiodiagnostik chirurgischer Faecher, Universitaetsklinik fuer Radiodiagnostik, Wien (Austria); Ludwig-Boltzmann-Institut fuer Radiologische Tumordiagnostik, Wien (Austria); Mayerhoefer, M. [Klinische Abteilung fuer Radiodiagnostik chirurgischer Faecher, Universitaetsklinik fuer Radiodiagnostik, Wien (Austria); Gottsauner-Wolf, F. [Universitaetsklinik fuer Orthopaedie, Wien (Austria); Abteilung fuer Orthopaedie, Allgemeines oeffentliches KH, Krems (Austria); Krestan, C.; Imhof, H. [Abteilung fuer Osteologie, Universitaetsklinik fuer Radiodiagnostik, Wien (Austria); Toma, C.D. [Universitaetsklinik fuer Orthopaedie, Wien (Austria)


    Hip arthroplasty has become a common and still increasing procedure for the treatment of osteoarthritis, advanced head necrosis, post-inflammatory arthritis or rheumatoid arthritis.Radiography is the most important imaging modality for monitoring the normal, asymptomatic hip arthroplasty. Radiographs are obtained at the end of a surgical treatment, to exclude complications like fracture or component misplacement. In the follow-up radiographs are used for the diagnosis of loosening and infection of the hip arthroplasty as well as soft tissue ossification. Together with the history and clinical information, the analysis of morphological findings allows to find the grade of loosening. MRI has been advocated in the diagnosis of infection, in particular in the localisation of soft tissue involvement.Imaging, especially by radiographs, is used for the evaluation of the normal and complicated follow-up of hip arthroplasty. (orig.) [German] Die Implantation einer Hueftgelenkprothese ist eine immer haeufiger verwendete medizinische Massnahme bei Erkrankungen des Hueftgelenks wie Koxarthrose, Hueftkopfnekrose, postentzuendliche Arthrose oder rheumatoide Arthritis.Von den bildgebenden Methoden ist das konventionelle Roentgen die wichtigste Untersuchung, um den normalen Behandlungsverlauf einer Hueftprothese zu monitieren. Das Roentgen kann fruehzeitige Komplikationen wie Fraktur oder Fehlposition intraoperativ oder eine Luxation postoperativ erfassen. Im laengerfristigen Verlauf ist das Roentgen zur Diagnose von Infektion, Prothesenlockerung und Weichteilverknoecherung geeignet. In Zusammenschau mit der Klinik ermoeglicht die Analyse morphologisch-radiologischer Details, die Wahrscheinlichkeit einer Lockerung abzuschaetzen. Bei Protheseninfektionen ermoeglicht die MRT die Lokalisation von Weichteilentzuendungen.Die Methoden der Bildgebung, besonders das Roentgen, haben in der Beurteilung des normalen und in der Diagnose des komplizierten Verlaufes einen hohen Stellenwert

  14. Stemless shoulder arthroplasty: a literature review



    The design of humeral implants for shoulder arthroplasty has evolved over the years. The new-generation modular shoulder prostheses have an anatomical humeral stem that replicates the three-dimensional parameters of the proximal humerus. An anatomical reconstruction is the best way to restore stability and mobility of the prosthetic shoulder and improve implant durability. However, a perfect anatomical match is not always possible in, for example, patients with post-traumatic osteoarthritis o...

  15. Analysis of the unicompartmental knee arthroplasty results

    S. A. Firsov


    Full Text Available In 2012-2014 total 67 unicompartmental arthroplasty surgeries with use of Oxford knee meniscal bearing were performed. The surgeries were performed by a single surgeon. Minimally invasive approach was used. All patients were evaluated clinically, radiographically and with Oxford Knee score scale, Knee Society score scale and functional scale. Obtained data was processed with nonparametric Mann-Whitney-Wilcoxon test. Results were processed using the statistical analysis application package SPSS, version 10.07. Analysis of of mid-term results showed that the average for Oxford Knee score increased from 16.4 (95% CI 9-23 to 41.3 (95% CI 29-47. Average for Knee Society score scale increased from 42.7 (95% CI 31-55 to 88.6 (95% CI 73-100. No occurrence of early postoperative complications have been reported. Statistically significant improvements of knee function in patients after unicompartmental arthroplasty have been observed. Unicompartmental arthroplasty currently can be considered as an advanced treatment option for medial knee joint pathology. Meniscal bearing cemented prostheses such as Oxford III are preferable.

  16. Recurrent hemarthrosis after unicompartmental knee arthroplasty.

    Asanuma, Kunihiro; Ito, Haruo; Ogawa, Akito; Asanuma, Yumiko; Yoshikawa, Tomoaki; Hasegawa, Masahiro; Sudo, Akihiro


    Recurrent hemarthrosis after knee arthroplasty can be disabling, requiring adequate and immediate diagnosis and treatment for recovery of symptoms and joint function. The most commonly reported cause is impingement of proliferative synovium between prosthetic components. Although various procedures for hemarthrosis have been reported after knee arthroplasty for patients who do not respond to conservative treatment, the recommended first-line therapy is open surgery or embolization. Although hyperplastic synovium was observed during the first and second arthrotomy, in our case, tissue impingement was not detected. We describe a rare case of recurrent hemarthrosis after unicompartmental knee arthroplasty (UKA) and successful treatment by open synovectomy. A 66-year-old woman presented with spontaneous osteonecrosis of the medial femoral condyle in the right leg. She underwent UKA of the right knee of the medial condyle. Eighteen months after UKA, the patient developed recurrent hemarthrosis. Open arthrotomy was performed 22 months after UKA, revealing only hematoma with no obvious hemorrhage or loosening of the prosthesis. No history of trauma or use of anticoagulant medications was present. After a symptom-free period of 8 months, another 2 episodes of hemarthrosis occurred over the course of 8 months. A second open arthrotomy was performed. Hyperplastic synovium with fibrin and hemosiderin pigmentation was observed, again without hemorrhage or loosening. There were no pathological features of pigmented villonodular synovitis. Synovectomy was performed, and no hemarthrosis has recurred for 2 years.

  17. Biomechanical study of intervertebral disc degeneration

    González Guitiérrez, Ramiro Arturo


    Degeneration and age affect the biomechanics of the intervertebral disc, by reducing its stiffness, flexibility and shock absorption capacities against daily movement and spinal load. The biomechanical characterization of intervertebral discs is achieved by conducting mechanical testing to vertebra-disc-vertebra segments and applying axial, shear, bend and torsion loads, statically or dynamically, with load magnitudes corresponding to the physiological range. However, traditional testing does...

  18. DSC Study of Collagen in Disc Disease

    S. Skrzyński; Sionkowska, A.; Marciniak, A.


    Differential scanning calorimetry (DSC) has been used to estimate the effect of disc disease on the collagen helix-coil transition and morphology for tissue extracted from patients during surgical operation. Forty discs were obtained from patients with degenerative disc disease undergoing surgery for low back pain. The patients were in the age between 20 and 70 years old. The specimens were kept wet during DSC experiment. The data allow the comparison between thermal stability of collagen ti...

  19. Biomechanical study of intervertebral disc degeneration

    González Guitiérrez, Ramiro Arturo


    Degeneration and age affect the biomechanics of the intervertebral disc, by reducing its stiffness, flexibility and shock absorption capacities against daily movement and spinal load. The biomechanical characterization of intervertebral discs is achieved by conducting mechanical testing to vertebra-disc-vertebra segments and applying axial, shear, bend and torsion loads, statically or dynamically, with load magnitudes corresponding to the physiological range. However, traditional testing does...

  20. The Roles of Discs for Planetary Systems

    Yeh, L C; Yeh, Li-Chin; Jiang, Ing-Guey


    It is known that the discs are detected for some of the extra-solar planetary systems. It is also likely that there was a disc mixing with planets and small bodies while our Solar System was forming. From our recent results, we conclude that the discs play two roles: the gravity makes planetary systems more chaotic and the drag makes planetary systems more resonant.

  1. DISC1 genetics, biology and psychiatric illness


    Psychiatric disorders are highly heritable, and in many individuals likely arise from the combined effects of genes and the environment. A substantial body of evidence points towards DISC1 being one of the genes that influence risk of schizophrenia, bipolar disorder and depression, and functional studies of DISC1 consequently have the potential to reveal much about the pathways that lead to major mental illness. Here, we review the evidence that DISC1 influences disease risk through effects u...

  2. Perioperative blood saving measures in total hip and knee arthroplasty

    Horstmann, W.G.


    This dissertation explores and discusses different aspects of blood loss and blood-saving measures in total hip and knee arthroplasty. Background: Worldwide, approximately 1 million total hip and 1 million total knee prostheses are implanted each year. Total hip arthroplasty and total knee art

  3. Bicompartmental knee arthroplasty of the patellofemoral and medial compartments.

    Thienpont, Emmanuel; Price, Andrew


    Studies have shown that after total knee arthroplasty neither normal biomechanics nor function is obtained. Selective resurfacing of diseased compartments could be a solution. A narrative review of the available literature on bicompartmental arthroplasty is presented. A literature review of all peer reviewed published articles on bicompartmental arthroplasty of the knee was performed. Bicompartmental arthroplasty is by definition the replacement of the tibiofemoral and the patellofemoral joint. It can be performed with a modular unlinked or a monolithic femoral component. Bicompartmental arthroplasty performed with modular components obtains good to excellent results at ± 10 years follow-up. Function and biomechanics are superior to total knee arthroplasty. Modern monolithic femoral components are reported to give early failure and high revision rates and should be avoided. Modular bicompartmental arthroplasty is an excellent alternative to treat bicompartmental arthritis of the knee leading to good functional results and superior biomechanics in well-selected patients. Caution is needed since only a few peer reviewed articles with small series and old implant designs are available on this type of arthritis treatment. Survivorship in these studies is inferior to total knee arthroplasty.

  4. Patient-reported outcome after fast-track knee arthroplasty

    Larsen, Kristian; Hansen, Torben B; Søballe, Kjeld;


    PURPOSE: The purpose of this study was to describe patient-related functional outcomes after fast-track total knee arthroplasty and unicompartmental knee arthroplasty. Furthermore, we wanted to assess physical areas where an additional need for rehabilitation could be identified, and finally, we...

  5. The quiescent phase of galactic disc growth

    Aumer, Michael; Binney, James; Schönrich, Ralph


    We perform a series of controlled N-body simulations of growing disc galaxies within non-growing, live dark matter haloes of varying mass and concentration. Our initial conditions include either a low-mass disc or a compact bulge. New stellar particles are continuously added on near-circular orbits to the existing disc, so spiral structure is continuously excited. To study the effect of combined spiral and giant molecular cloud (GMC) heating on the discs, we introduce massive, short-lived particles that sample a GMC mass function. An isothermal gas component is introduced for a subset of the models. We perform a resolution study and vary parameters governing the GMC population, the histories of star formation and radial scale growth. Models with GMCs and standard values for the disc mass and halo density provide the right level of self-gravity to explain the age-velocity dispersion relation of the solar neighbourhood (Snhd). GMC heating generates remarkably exponential vertical profiles with scaleheights that are radially constant and agree with observations of galactic thin discs. GMCs are also capable of significantly delaying bar formation. The amount of spiral-induced radial migration agrees with what is required for the metallicity distribution of the Snhd. However, in our standard models, the outward-migrating populations are not hot enough vertically to create thick discs. Thick discs can form in models with high baryon fractions, but the corresponding bars are too long, the young stellar populations too hot and the discs flare considerably.

  6. Accretion Discs Show Their True Colours


    Quasars are the brilliant cores of remote galaxies, at the hearts of which lie supermassive black holes that can generate enough power to outshine the Sun a trillion times. These mighty power sources are fuelled by interstellar gas, thought to be sucked into the hole from a surrounding 'accretion disc'. A paper in this week's issue of the journal Nature, partly based on observations collected with ESO's Very Large Telescope, verifies a long-standing prediction about the intensely luminous radiation emitted by these accretion discs. Uncovering the disc ESO PR Photo 21/08 Uncovering the inner disc "Astronomers were puzzled by the fact that the best models of these discs couldn't quite be reconciled with some of the observations, in particular, with the fact that these discs did not appear as blue as they should be," explains lead-author Makoto Kishimoto. Such a discrepancy could be the signal that there was something very wrong with the models. With his colleagues, he investigated this discrepancy by studying the polarised light from six quasars. This enabled them to demonstrate that the disc spectrum is as blue as predicted. "The crucial observational difficulty here has been that the disc is surrounded by a much larger torus containing hot dust, whose light partly outshines that of the disc," says Kishimoto. "Because the light coming from the disc is scattered in the disc vicinity and thus polarised, by observing only polarised light from the quasars, one can uncover the buried light from the disc." In a similar way that a fisherman would wear polarised sunglasses to help get rid of the glare from the water surface and allow him to see more clearly under the water, the filter on the telescope allowed the astronomers to see beyond surrounding clouds of dust and gas to the blue colour of the disc in infrared light. The observations were done with the FORS and ISAAC instruments on one of the 8.2-m Unit Telescopes of ESO's Very Large Telescope, located in the Atacama

  7. DSC Study of Collagen in Disc Disease

    S. Skrzyński


    Full Text Available Differential scanning calorimetry (DSC has been used to estimate the effect of disc disease on the collagen helix-coil transition and morphology for tissue extracted from patients during surgical operation. Forty discs were obtained from patients with degenerative disc disease undergoing surgery for low back pain. The patients were in the age between 20 and 70 years old. The specimens were kept wet during DSC experiment. The data allow the comparison between thermal stability of collagen tissue from healthy patients and from patients suffering from disc disease. In the paper the comparison between thermal helix-coil transition for collagen fibers from patients suffering from disc disease and collagen fibers from healthy organisms has been discussed. The heating rate has an influence on the position on denaturation temperatures of collagen in disc tissues. Higher helix-coil transition temperature of collagen in degenerated disc suggests that additional intermolecular cross linking of collagen fibers occurs. Denaturation temperatures of collagen in degenerated male disc possess smaller values than in female ones. Disc disease induces changes in collagen structure and leads to formation of additional crosslinks between collagen fibers.

  8. Computing Decoupled Residuals for Compact Disc Players

    Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle


    In order to improve Compact Disc Players playability regarding playing Compact Discs with surface faults, like scratches and fingerprints etc, the attention has been put on fault tolerant control schemes. Almost every of those methods are based on fault detection. The standard approach is to use...... a pair of residuals generated by Compact Disc Player. However, these residuals depend on the performance of position servos in the Compact Disc Player. In other publications of the same authors a pair of decoupled residuals is derived. However, the computation of these alternative residuals has been...

  9. [Controlled distraction as a therapeutic option in moderate degeneration of the intervertebral disc -- an in vivo study in the rabbit-spine model].

    Unglaub, F; Guehring, T; Omlor, G; Lorenz, H; Carstens, C; Kroeber, M W


    The aim of this study was to investigate the effects of temporary distraction on a degenerated intervertebral disc to characterize regenerative changes associated with disc distraction. New Zealand white rabbits (n = 32) were used for this experimental animal study. The rabbits were randomly assigned to one of five groups. 6 animals were loaded for 28 days using a custom-made external loading device to stimulate disc degeneration (G2). In 6 animals the discs were first loaded for 28 days and after 28 days loading time the discs in six animals were treated as dynamic distraction with an external distraction device (G1). In six animals the discs were distracted for 28 days without previous loading (G5) and in six animals the discs were loaded for 28 days and afterwards the loading device was removed for 28 days for recovery without distraction (G3). Six animals were sham operated (G4) without application of axial load. After 28 to 56 days loading and distraction time, the animals were sacrificed and the lumbar spine was harvested for histological and radiographic analysis. Histology was performed according to a degeneration score and disc height was calculated radiographically. For the cell viability examination, the number of apoptotic cells was determined. After 28 days of loading (G2), the discs showed a significant decrease in disc space of the treated segment. Histologically, a disorganization of the architecture of the annulus occurred. The number of dead cells increased significantly in the annulus and cartilage endplate. These changes were reversible after 28 days of distraction (G1). The disc thickness increased significantly to physiological levels as compared to the specimens from the 28 days loading group without distraction. Histologically, the discs showed signs of tissue regeneration after 28 days of distraction (G1). The number of apoptotic cells decreased significantly in comparison to the loaded discs without distraction (G2). The results of this

  10. Evolution of linear warps in accretion discs and applications to protoplanetary discs in binaries

    Foucart, Francois


    The existence of warped accretion discs is expected in a wide variety of astrophysical systems, including circumstellar discs in binaries and discs around binary protostars. A common feature of these discs is that they are perturbed by a misaligned external potential. In this paper, we study the long-term evolution of the disc warp and precession in the case of thick discs (with the dimensionless thickness $H/r$ larger than the viscosity parameter $\\alpha$) in which bending waves can propagate. For small warps, such discs undergo approximately rigid-body precession with a coherent global frequency. We derive the analytical expressions for the warp/twist profiles of the disc and the alignment timescale for a variety of disc models/parameters. Applying our results to circumbinary discs, we find that these discs align with the orbital plane of the binary on a timescale comparable to the global precession time of the disc, and typically much smaller than its viscous timescale. The development of parametric instab...

  11. Circumplanetary discs around young giant planets: a comparison between core-accretion and disc instability

    Szulágyi, J.; Mayer, L.; Quinn, T.


    Circumplanetary discs can be found around forming giant planets, regardless of whether core accretion or gravitational instability built the planet. We carried out state-of-the-art hydrodynamical simulations of the circumplanetary discs for both formation scenarios, using as similar initial conditions as possible to unveil possible intrinsic differences in the circumplanetary disc mass and temperature between the two formation mechanisms. We found that the circumplanetary discs' mass linearly scales with the circumstellar disc mass. Therefore, in an equally massive protoplanetary disc, the circumplanetary discs formed in the disc instability model can be only a factor of 8 more massive than their core-accretion counterparts. On the other hand, the bulk circumplanetary disc temperature differs by more than an order of magnitude between the two cases. The subdiscs around planets formed by gravitational instability have a characteristic temperature below 100 K, while the core-accretion circumplanetary discs are hot, with temperatures even greater than 1000 K when embedded in massive, optically thick protoplanetary discs. We explain how this difference can be understood as the natural result of the different formation mechanisms. We argue that the different temperatures should persist up to the point when a full-fledged gas giant forms via disc instability; hence, our result provides a convenient criterion for observations to distinguish between the two main formation scenarios by measuring the bulk temperature in the planet vicinity.

  12. [Revision arthroplasty of the ankle joint].

    Hintermann, B; Barg, A; Knupp, M


    In the last 20 years total ankle replacement has become a viable alternative to arthrodesis for end-stage osteoarthritis of the ankle. Numerous ankle prosthesis designs have appeared on the market in the past and attracted by the encouraging intermediate results reported in the literature, many surgeons have started to perform this procedure. With increased availability on the market the indications for total ankle replacement have also increased in recent years. In particular, total ankle replacement may now be considered even in younger patients. Therefore, despite progress in total ankle arthroplasty the number of failures may increase. Up to now, arthrodesis was considered to be the gold standard for salvage of failed ankle prostheses. Because of extensive bone loss on the talar side, in most instances tibiocalcaneal fusion is the only reliable solution. An alternative to such extended hindfoot fusions would be revision arthroplasty. To date, however, there are no reported results of revision arthroplasty for salvage of a failed ankle replacement.Based on our experience prosthetic components with a flat undersurface are most likely to be able to find solid support on remaining bone stock. The first 83 cases (79 patients, 46 males, 33 females, average age 58.9 years, range 30.6-80.7 years) with a average follow-up of 5.4 years (range 2-11 years) showed excellent to good results in 69 cases (83%), a satisfactory result in 12 cases (15%) and a fair result in 2 cases (2%) and 47 patients (56%) were pain free. Primary loosening was noted in three cases and of these two cases were successfully revised by another total ankle replacement and in one case with arthrodesis. Another case with hematogenous infection was also revised by arthrodesis. At the last follow-up control two components were considered to be loose and the overall loosening rate was thus 6%.This series has proven that revision arthroplasty can be a promising option for patients with failed total

  13. [Standardized terminology for disc disease].

    Sánchez Pérez, M; Gil Sierra, A; Sánchez Martín, A; Gallego Gómez, P; Pereira Boo, D


    This article reviews the terminology used to describe morphological alterations in the intervertebral discs. Radiologists must be able to communicate information about the type, location, and severity of these alterations to medical and surgical clinicians. It is crucial to use simple, standard, and unified terminology to ensure comprehension not only among radiologists but also with professionals from the different specialties for whom the radiology reports are written (fundamentally traumatologists and neurosurgeons). This terminology will help ensure a more accurate diagnosis and better patient management.

  14. Digital versus analogue preoperative planning of total hip arthroplasties - A randomized clinical trial of 210 total hip arthroplasties

    The, Bertram; Verdonschot, Nico; van Horn, Jim R.; van Ooijen, Peter M. A.; Diercks, Ron L.


    The objective of this randomized clinical trial was to compare the clinical and technical results of digital preoperative planning for primary total hip arthroplasties with analogue planning. Two hundred and ten total hip arthroplasties were randomized. All plans were constructed on standardized rad

  15. Reverse-total shoulder arthroplasty cost-effectiveness: A quality-adjusted life years comparison with total hip arthroplasty.

    Bachman, Daniel; Nyland, John; Krupp, Ryan


    To compare reverse-total shoulder arthroplasty (RSA) cost-effectiveness with total hip arthroplasty cost-effectiveness. This study used a stochastic model and decision-making algorithm to compare the cost-effectiveness of RSA and total hip arthroplasty. Fifteen patients underwent pre-operative, and 3, 6, and 12 mo post-operative clinical examinations and Short Form-36 Health Survey completion. Short form-36 Health Survey subscale scores were converted to EuroQual Group Five Dimension Health Outcome scores and compared with historical data from age-matched patients who had undergone total hip arthroplasty. Quality-adjusted life year (QALY) improvements based on life expectancies were calculated. The cost/QALY was $3900 for total hip arthroplasty and $11100 for RSA. After adjusting the model to only include shoulder-specific physical function subscale items, the RSA QALY improved to 2.8 years, and its cost/QALY decreased to $8100. Based on industry accepted standards, cost/QALY estimates supported both RSA and total hip arthroplasty cost-effectiveness. Although total hip arthroplasty remains the quality of life improvement "gold standard" among arthroplasty procedures, cost/QALY estimates identified in this study support the growing use of RSA to improve patient quality of life.

  16. Transabdominal sonography of lumbar intervertebral discs and intraspinal structures

    Toelly, E.


    This paper reports a prospective study on 64 patients in whom sonography was used to diagnose pathological changes in lumbar discs and intraspinal space occupying lesions; the results were compared with myelography and computer assisted tomography (CAT). The sonography device used was a mechanical sector scanner with a medium focused transducer with a frequency of 3.5 MHz. The normal and pathological anatomy as shown by ultrasound was correlated to the known anatomy of CAT-scanning; the nerve roots, the dural sac and the intervertebral disc were recognizable in sonography and in CAT. The extent of an intraspinal lesion beyond the upper and lower limiting planes of the intervertebral discs were not demonstrable by ultrasound. The sonographic study was at least partially successful in 55 of 64 patients (86%). It failed in 14% (9 cases) because of obesity or because of diminution of the intervertebral space. The study revealed a specifity and sensitivity of transabdominal spinal sonography of 0.86 respectively 0.84.

  17. Minimum weight design of inhomogeneous rotating discs

    Jahed, Hamid [Department of Mechanical Engineering, Iran University of Science and Technology, Tehran 16844 (Iran, Islamic Republic of); Farshi, Behrooz [Department of Mechanical Engineering, Iran University of Science and Technology, Tehran 16844 (Iran, Islamic Republic of)]. E-mail:; Bidabadi, Jalal [Department of Mechanical Engineering, Iran University of Science and Technology, Tehran 16844 (Iran, Islamic Republic of)


    There are numerous applications for gas turbine discs in the aerospace industry such as in turbojet engines. These discs normally work under high temperatures while subjected to high angular velocities. Minimizing the weight of such items in aerospace applications results in benefits such as low dead weights and lower costs. High speed of rotation causes large centrifugal forces in a disc and simultaneous application of high temperatures reduces disc material strength. Thus, the latter effects tend to increase deformations of the disc under the applied loads. In order to obtain a reliable disc analysis and arrive at the corresponding correct stress distribution, solutions should consider changes in material properties due to the temperature field throughout the disc. To achieve this goal, an inhomogeneous disc model with variable thickness is considered. Using the variable material properties method, stresses are obtained for the disc under rotation and a steady temperature field. In this paper this is done by modelling the rotating disc as a series of rings of different but constant properties. The optimum disc profile is arrived at by sequentially proportioning the thicknesses of each ring to satisfy the stress requirements. This method vis-a-vis a mathematical programming procedure for optimization shows several advantages. Firstly, it is simple iterative proportioning in each design cycle not requiring involved mathematical operations. Secondly, due to its simplicity it alleviates the necessity of certain simplifications that are common in so-called rigorous mathematical procedures. The results obtained, compared to those published in the literature show agreement and superiority. A further advantage of the proposed method is the independence of the end results from the initially assumed point in the iterative design routine, unlike most methods published so far.

  18. The use of a constrained acetabular component to treat instability after total hip arthroplasty.

    Shrader, M Wade; Parvizi, Javad; Lewallen, David G


    Recurrent dislocation after total hip arthroplasty is a disabling complication that can be difficult to treat and may not be amenable to nonoperative management. The purpose of the present study was to evaluate the clinical and radiographic outcome associated with the use of a constrained acetabular component as a salvage treatment for instability after hip arthroplasty. We retrospectively reviewed the clinical and radiographic outcome of 110 arthroplasties, in 109 patients, that had been performed with use of a single design of constrained acetabular component. In seventy-nine hips the constrained component was implanted for the treatment of recurrent instability, and in thirty-one hips it was implanted because of absent or grossly deficient soft-tissue attachments that were believed to be associated with a high risk for subsequent instability. The constrained acetabular device eliminated or prevented hip instability in all patients except two, who continued to have sensations of subluxation. The mean Harris hip score improved significantly, from 62.7 points preoperatively to 76.4 points at the time of the latest follow-up (p acetabular component loosening, and one for a periprosthetic fracture of the femur. A constrained acetabular component reliably restores and maintains hip stability in patients with recalcitrant recurrent instability and can dependably prevent dislocation in those who are at high risk because of absent or deficient soft tissues about the hip. However, because of the early appearance of radiolucent lines around some components and concerns about long-term fixation, the use of these devices should be reserved for situations in which other methods are inadequate or have already failed.

  19. Methodology for optic disc localization

    Marcos A. Leiva-Vasconcellos


    Full Text Available The use of digital images in many areas of society is an activity that has reached a remarkable growth in recent years mainly due to the great development that has occurred in technology around the world. These images have a great use in many branches of medicine because they facilitate the diagnosis by specialists and thus help patients to be diagnosed long before symptoms of the disease begin to manifest. For Ophthalmology, one of the most used images are the digital retinography, If it is used properly will allow the occurrence of eye diseases such as glaucoma and diabetic retinopathy. One of the main elements shown on retinal images are the optic disc, the location and detection is of vital importance for working with different parts of the structure o f the eye. This paper proposes two techniques for locating the optic disc in retinal images based on the combination of multiple filters and applying logical operators. To test the algorithms diaretDB0v11 and DRIVE database were used , as a result of the tests are correctly located the 99.091 % of the images from both repo sitories, and were successfully detected 85 % and 87.143 % of images of DRIVE database and diaretDB0v11 respectively.

  20. Biomechanical comparison of a two-level Maverick disc replacement with a hybrid one-level disc replacement and one-level anterior lumbar interbody fusion.

    Erkan, Serkan; Rivera, Yamil; Wu, Chunhui; Mehbod, Amir A; Transfeldt, Ensor E


    preserved total motion but altered the motion pattern of the intact condition. This result is similar to unconstrained devices such as Charité. The motion at L4-L5 of the hybrid model is similar to that of two-level Maverick disc replacement. The fusion procedure using an anterior plate significantly reduced intact motion. Clinical studies are recommended to validate the efficacy of the hybrid model.


    Vladimir E. Baskov


    Full Text Available Introduction. Treating children with degenerative dystrophic diseases of the hip joint has become one of the most acute problems in contemporary orthopedics. Until recently, we performed arthroplasty by demineralized bone-cartilage allocups (DBCA in the Clinic of the Hip Joint Pathology of the Turner Scientific and Research Institute for Children’s Orthopedics for patients showing clinical and radiological signs of irreversible destruction of the hip joint; we carried out this procedure to preserve the function of the lower limb. However, over the last 8 years, we have changed our protocol for children older than 12 years of age and have replaced DBCA with total hip replacement. In a number of cases, total hip replacement was performed after a previous intervention involving arthroplasty with DBCA. Objective. To determine the technical peculiarities of total hip replacement after a previous intervention involving arthroplasty with DBCA. Material and methods. We analyzed the results of treatment involving various types of hip pathology in 13 children (100% aged between 15 and 16 years [8 girls (61.5% and 5 boys (38.5%]. The medical histories of all 13 children (100% showed repeated operations on the hip joint, ultimately resulting in arthroplasty with DBCA. All 13 children (100% underwent a total hip replacement. Upon hip replacement, all 13 patients (100% showed a pronounced thinning and hardening of the edges and the bottom of the acetabulum, which created some difficulties in the process of acetabular component implantation. The transformation of DBCA was not evident in any of the 13 cases (100%. Results. During the observation period of 3–5 years following total hip arthroplasty, all 13 cases (100% showed recovery in the range of motion and absence of pain. An important criterion for evaluating the quality of care was the complete social and domestic adaptation of all 13 children (100% during the period from 6 to 9 months following total

  2. A Simulation Model of Focus and Radial Servos in Compact Disc Players with Disc Surface Defects

    Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle


    Compact Disc players have been on the market in more than two decades.As a consequence most of the control servo problems have been solved. A large remaining problem to solve is the handling of Compact Discs with severe surface defects like scratches and fingerprints. This paper introduces a method...... for making the design of controllers handling surface defects easier. A simulation model of Compact Disc players playing discs with surface defects is presented. The main novel element in the model is a model of the surface defects. That model is based on data from discs with surface defects. This model...

  3. The physics of pressure variation in microchannels within corotating or static discs

    Guha, Abhijit; Sengupta, Sayantan


    We formulate a comprehensive analysis for the radial pressure variation in flow through microchannels within corotating (or static) discs, which is important for its fundamental value and application potential in macrofluidic and microfluidic devices. The uniqueness and utility of the present approach emanate from our ability to describe the physics completely in terms of non-dimensional numbers and to determine quantitatively the separate roles of inertia, centrifugal force, Coriolis force, and viscous effects in the overall radial pressure difference (Δpio). It is established here that the aspect ratio (ratio of inter-disc spacing and disc radius) plays only a secondary role as an independent parameter, its major role being contained within a newly identified dynamic similarity number (Ds). For radial inflow, it is shown that the magnitude of Δpio decreases monotonically as the tangential speed ratio (γ) increases but exhibits a minima when Ds is varied. For radial outflow, it is shown that Δpio increases monotonically as the flow coefficient (ϕ) decreases but evinces a maxima when Ds is varied. It is further shown that for the radial inflow case, the minima in the magnitude of Δpio exist even when the rotational speed of the discs is reduced to zero (static discs). The demonstrated existence of these extrema (i.e., minima for radial inflow and maxima for radial outflow) creates the scope for device optimization.

  4. Electromagnetic fields in the treatment of chronic lower back pain in patients with degenerative disc disease

    Arneja, Amarjit S; Kotowich, Alan; Staley, Doug; Summers, Randy; Tappia, Paramjit S


    Aim: To examine the effects of low-amplitude, low frequency electromagnetic field therapy (EMF) therapy in patients with persistent chronic lower back pain associated with degenerative disc disease. Design: Double-blind, randomized and placebo controlled. Intervention: EMF using a medical device resonator; control group underwent same procedures, except the device was turned off. Outcome measures: Pain reduction and mobility. Results: Improvements in overall physical health, social functionin...

  5. Post-Main Sequence Evolution of Debris Discs

    Bonsor, Amy; Wyatt, Mark


    The population of debris discs on the main sequence is well constrained, however very little is known about debris discs around evolved stars. In this work we provide a theoretical framework that considers the effects of stellar evolution on debris discs; firstly considering the evolution of an individual disc from the main sequence through to the white dwarf phase, then extending this to the known population of debris discs around main sequence A stars. It is found that discs around evolved ...

  6. Thin, thick and dark discs in LCDM

    Read, J I; Agertz, O; Debattista, Victor P


    In a LCDM cosmology, the Milky Way accretes satellites into the stellar disc. We use cosmological simulations to assess the frequency of near disc plane and higher inclination accretion events, and collisionless simulations of satellite mergers to quantify the final state of the accreted material and the effect on the thin disc. On average, a Milky Way-sized galaxy has 1.5 subhalos with vmax>80km/s; 5 with vmax>60km/s; and 13 with vmax>40km/s merge at redshift z>1. A third of these merge at an impact angle 20 degrees) are twice as likely as low inclination ones. These lead to structures that closely resemble the recently discovered inner/outer stellar halos. They also do more damage to the Milky Way stellar disc creating a more pronounced flare, and warp; both long-lived and consistent with current observations. The most massive mergers (vmax > 80km/s) heat t he thin disc enough to produce a thick disc. These heated thin disc stars are essential for obtaining a thick disc as massive as that seen in the Milky ...

  7. Hygroviscoelasticity of the Human Intervertebral Disc.


    hernia - tion with age depends on the biochemical changes that occur in the material of the disc during its maturation process. However, a careful machanics...EFFORT One of the recurring pieces of information required in disc response is the intra- discal pressure when the spine is loaded axially. This

  8. Hydromagnetic Flow between Two Rotating Coaxial Discs

    Abdul Aleem Khan


    Full Text Available This paper relates to the steady flow of an electrically incompressible viscous fluid between two parallel coaxial rotating discs with a transverse magnetic field when the discs are rotating in the same direction with the same velocity and there is a source at the centre.

  9. Genetic association studies in lumbar disc degeneration

    Eskola, Pasi J; Lemmelä, Susanna; Kjaer, Per


    Low back pain is associated with lumbar disc degeneration, which is mainly due to genetic predisposition. The objective of this study was to perform a systematic review to evaluate genetic association studies in lumbar disc degeneration as defined on magnetic resonance imaging (MRI) in humans....

  10. Requirements for an artificial intervertebral disc

    Eijkelkamp, MF; van Donkelaar, CC; Veldhuizen, AG; van Horn, [No Value; Huyghe, JM; Verkerke, GJ

    Intervertebral disc degeneration is an important social and economic problem. Presently available artificial intervertebral discs (AIDs) are insufficient and the main surgical intervention is still spinal fusion. The objective of the present study is to present a list of requirements for the

  11. Feature Based Control of Compact Disc Players

    Odgaard, Peter Fogh

    Two servo control loops are used to keep the Optical Pick-up Unit focused and radially on the information track of the Compact Disc. These control servos have problems handling surface faults on the Compact Disc. In this Ph.D thesis a method is proposed to improve the handling of these surface...

  12. The inner cavity of the circumnuclear disc

    Blank, M.; Morris, M. R.; Frank, A.; Carroll-Nellenback, J. J.; Duschl, W. J.


    The circumnuclear disc (CND) orbiting the Galaxy's central black hole is a reservoir of material that can ultimately provide energy through accretion, or form stars in the presence of the black hole, as evidenced by the stellar cluster that is presently located at the CND's centre. In this paper, we report the results of a computational study of the dynamics of the CND. The results lead us to question two paradigms that are prevalent in previous research on the Galactic Centre. The first is that the disc's inner cavity is maintained by the interaction of the central stellar cluster's strong winds with the disc's inner rim, and secondly, that the presence of unstable clumps in the disc implies that the CND is a transient feature. Our simulations show that, in the absence of a magnetic field, the interaction of the wind with the inner disc rim actually leads to a filling of the inner cavity within a few orbital time-scales, contrary to previous expectations. However, including the effects of magnetic fields stabilizes the inner disc rim against rapid inward migration. Furthermore, this interaction causes instabilities that continuously create clumps that are individually unstable against tidal shearing. Thus the occurrence of such unstable clumps does not necessarily mean that the disc is itself a transient phenomenon. The next steps in this investigation are to explore the effect of the magnetorotational instability on the disc evolution and to test whether the results presented here persist for longer time-scales than those considered here.

  13. The maximum rotation of a galactic disc

    Bottema, R


    The observed stellar velocity dispersions of galactic discs show that the maximum rotation of a disc is on average 63% of the observed maximum rotation. This criterion can, however, not be applied to small or low surface brightness (LSB) galaxies because such systems show, in general, a continuously

  14. 46 CFR 154.912 - Inerted spaces: Relief devices.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Inerted spaces: Relief devices. 154.912 Section 154.912... Atmospheric Control in Cargo Containment Systems § 154.912 Inerted spaces: Relief devices. Inerted spaces must be fitted with relief valves, rupture discs, or other devices specially approved by the...

  15. On the reliability of protostellar disc mass measurements and the existence of fragmenting discs

    Dunham, Michael M; Arce, Héctor G


    We couple non-magnetic, hydrodynamical simulations of collapsing protostellar cores with radiative transfer evolutionary models to generate synthetic observations. We then use these synthetic observations to investigate the extent to which a simple method for measuring protostellar disc masses used in the literature recovers the intrinsic masses of the discs formed in the simulations. We evaluate the effects of contamination from the surrounding core, partially resolving out the disc, optical depth, fixed assumed dust temperatures, inclination, and the dust opacity law. We show that the combination of these effects can lead to disc mass underestimates by up to factors of 2-3 at millimeter wavelengths and up to an order of magnitude or larger at submillimeter wavelengths. The optically thin portions of protostellar discs are generally cooler in the Class I stage than the Class 0 stage since Class I discs are typically larger and more optically thick, and thus more shielded. The observed disc mass distribution ...

  16. Twisted accretion discs: Pt. 4. Alignment in polytropic discs and low. cap alpha. limit

    Kumar, S.


    Twisted thin accretion discs are of interest in explaining long-term periodicities in X-ray binaries, the eclipse in Epsilon Aurigae, and perhaps precessing radio jets and possible warped molecular outflows in star-forming regions. Earlier results used isothermal discs to determine the alignment radius, Rsub(a). Now we see how polytropic discs effect earlier results for discs around compact objects and around close binaries. We find that Rsub(a) for polytropic discs can be up to an order of magnitude larger, depending on the polytropic index, the viscosity parameter and the precession mechanism. There is little change in the earlier conclusion that the case for alignment in Her X-1 is marginal, while there is substantial alignment in epsilon Aur. A lower limit is put on ..cap alpha.. for isothermal discs, which is expected to hold for polytropic discs as well. A bound is put on the energy of the perturbed flows.

  17. About detection of precessing circumpulsar discs

    Grimani, Catia


    Detections of circumpulsar discs and planetary systems through electromagnetic observations appear quite rare. In the case of PSR 1931+24 and B0656+14, the hypothesis of a precessing disc penetrating the pulsar light cylinder is found consistent with radio and gamma observations from these stars. Disc self-occultation and precession may affect electromagnetic measurements. We investigate here under which conditions gravitational waves generated by circumpulsar disc precession may be detected by the proposed second-generation space interferometers DECI-hertz Interferometer Gravitational Wave Observatory and Big Bang Observer. The characteristics of circumpulsar detectable precessing discs are estimated as a function of distance from the Solar system. Speculations on detection rates are presented.

  18. The formation of planets by disc fragmentation

    Stamatellos Dimitris


    Full Text Available I discuss the role that disc fragmentation plays in the formation of gas giant and terrestrial planets, and how this relates to the formation of brown dwarfs and low-mass stars, and ultimately to the process of star formation. Protostellar discs may fragment, if they are massive enough and can cool fast enough, but most of the objects that form by fragmentation are brown dwarfs. It may be possible that planets also form, if the mass growth of a proto-fragment is stopped (e.g. if this fragment is ejected from the disc, or suppressed and even reversed (e.g by tidal stripping. I will discuss if it is possible to distinguish whether a planet has formed by disc fragmentation or core accretion, and mention of a few examples of observed exoplanets that are suggestive of formation by disc fragmentation.

  19. Lumbar disc cyst with contralateral radiculopathy

    Kishore Tourani


    Full Text Available Disc cysts are uncommon intraspinal cystic lesions located in the ventrolateral epidural space. They communicate with the nucleus pulposus of the intervertebral disc and cause symptoms by radicular compression. We report a unique case of lumbar disc cyst that was associated with disc herniation and contralateral radiculopathy. A 22 year old male presented with one month history of back-ache radiating to the left leg. Magnetic Resonance Imaging (MRI showed L3-L4 disc herniation with annular tear and cystic lesion in the extradural space anterior to the thecal sac on right side, which increased in size over a period of 3 weeks. L3 laminectomy and bilateral discectomy and cyst excision was done with partial improvement of patients symptoms.

  20. Strongly magnetized accretion discs require poloidal flux

    Salvesen, Greg; Armitage, Philip J.; Simon, Jacob B.; Begelman, Mitchell C.


    Motivated by indirect observational evidence for strongly magnetized accretion discs around black holes, and the novel theoretical properties of such solutions, we investigate how a strong magnetization state can develop and persist. To this end, we perform local simulations of accretion discs with an initially purely toroidal magnetic field of equipartition strength. We demonstrate that discs with zero net vertical magnetic flux and realistic boundary conditions cannot sustain a strong toroidal field. However, a magnetic pressure-dominated disc can form from an initial configuration with a sufficient amount of net vertical flux and realistic boundary conditions. Our results suggest that poloidal flux is a necessary prerequisite for the sustainability of strongly magnetized accretion discs.

  1. Strongly magnetized accretion discs require poloidal flux

    Salvesen, Greg; Simon, Jacob B; Begelman, Mitchell C


    Motivated by indirect observational evidence for strongly magnetized accretion discs around black holes, and the novel theoretical properties of such solutions, we investigate how a strong magnetization state can develop and persist. To this end, we perform local simulations of accretion discs with an initially purely toroidal magnetic field of equipartition strength. We demonstrate that discs with zero net vertical magnetic flux and realistic boundary conditions cannot sustain a strong toroidal field. However, a magnetic pressure-dominated disc can form from an initial configuration with a sufficient amount of net vertical flux and realistic boundary conditions. Our results suggest that poloidal flux is a necessary prerequisite for the sustainability of strongly magnetized accretion discs.

  2. Magnetic resonance imaging of intervertebral disc degeneration

    Maeda, Hiroshi; Noguchi, Masao (Kitakyushu City Yahata Hospital, Fukuoka (Japan)); Kira, Hideaki; Fujiki, Hiroshi; Shimokawa, Isao; Hinoue, Kaichi


    The aim of this study was to correlate the degree of lumbar intervertebral disc degeneration with findings of magnetic resonance imaging (MRI). Seventeen autopsied (from 7 patients) and 21 surgical (from 20 patients) intervertebral discs were used as specimens for histopathological examination. In addition, 21 intervertebral discs were examined on T2-weighted images. Histopathological findings from both autopsied and surgical specimens were well correlated with MRI findings. In particular, T2-weighted images reflected increased collagen fibers and rupture within the fibrous ring accurately. However, when severely degenerated intervertebral discs and hernia protruding the posterior longitudinal ligament existed, histological findings were not concordant well with T2-weighted images. Morphological appearances of autopsy specimens, divided into four on T2-weighted images, were well consistent with histological degeneration. This morphological classification, as shown on T2-weighted images, could also be used in the evaluation of intervertebral disc degeneration. (N.K.).

  3. Lumbar Epidural Varix Mimicking Disc Herniation.

    Bursalı, Adem; Akyoldas, Goktug; Guvenal, Ahmet Burak; Yaman, Onur


    Lumbar radiculopathy is generally caused by such well-recognized entity as lumbar disc herniation in neurosurgical practice; however rare pathologies such as thrombosed epidural varix may mimic them by causing radicular symptoms. In this case report, we present a 26-year-old man with the complaint of back and right leg pain who was operated for right L4-5 disc herniation. The lesion interpreted as an extruded disc herniation preoperatively was found to be a thrombosed epidural varix compressing the nerve root preoperatively. The nerve root was decompressed by shrinking the lesion with bipolar thermocoagulation and excision. The patient's complaints disappeared in the postoperative period. Thrombosed lumbar epidural varices may mimic lumbar disc herniations both radiologically and clinically. Therefore, must be kept in mind in the differential diagnosis of lumbar disc herniations. Microsurgical techniques are mandatory for the treatment of these pathologies and decompression with thermocoagulation and excision is an efficient method.

  4. Angular momentum transport in protostellar discs

    Salmeron, Roberto Aureliano; Wardle, M; Salmeron, Raquel; Konigl, Arieh; Wardle, Mark


    Angular momentum transport in protostellar discs can take place either radially, through turbulence induced by the magnetorotational instability (MRI), or vertically, through the torque exerted by a large-scale magnetic field that threads the disc. Using semi-analytic and numerical results, we construct a model of steady-state discs that includes vertical transport by a centrifugally driven wind as well as MRI-induced turbulence. We present approximate criteria for the occurrence of either one of these mechanisms in an ambipolar diffusion-dominated disc. We derive ``strong field'' solutions in which the angular momentum transport is purely vertical and ``weak field'' solutions that are the stratified-disc analogues of the previously studied MRI channel modes; the latter are transformed into accretion solutions with predominantly radial angular-momentum transport when we implement a turbulent-stress prescription based on published results of numerical simulations. We also analyze ``intermediate field strength'...

  5. Unusual cases of pigmented villonodular synovitis after arthroplasty.

    Ma, Xiao-Mei; Xia, Chun-Yan; Fu, Pei-Liang; Liu, Hui-Min; Yu, Hong-Yu; He, Jin


    Pigmented Villonodular Synovitis (PVNS) is a relatively rare, benign proliferation lesion of the synovium of large joints. The etiology is varied and unclear. We had report a 79-year-old woman had PVNS after 14 years right hip arthroplasty with metal prosthesis. Here we report another 4 patients had PVNS after arthroplasty. The second one had PVNS in the 2(th) year after hip arthroplasty with bone cement prosthesis. The specimen was brown and like usual PVNS in tissue. The third case had PVNS in the 8(th) after arthroplasty with human bone prosthesis because of the recurrence of PVNS. The proliferated synovium became black from brown. There was brown and many groups black pigment in the tissue. The fourth one had PVNS in the 4(th) year after knee arthroplasty with polyethylene prosthesis. The specimen was yellow. There was no pigment in the tissue but multinucleated giant cells with unstained foreign body. The fifth patient had PVNS in the 10(th) month after the left hip arthroplasty with metal prosthesis. The macroscopy was yellow. There were hemosiderin particles in the tissue but black metal particles. This indicates that arthroplasty with prosthesis could cause some new disease or PVNS had new etiology with different pathological show.

  6. People who undergo revision arthroplasty report more limitations but no decrease in physical activity compared with primary total hip arthroplasty : an observational study

    Stevens, Martin; Hoekstra, Tsjerk; Wagenmakers, Robert; Bulstra, Sjoerd K.; van den Akker-Scheek, Inge


    Question: Do people who have had revision arthroplasty report more limitations and less physical activity than those after primary total hip arthroplasty? Can degree of limitation and physical activity be predicted by revision arthroplasty, after adjustment for age, gender, and Charnley classificati

  7. Total elbow arthroplasty: a radiographic outcome study

    Bai, Xue Susan [University of Washington, Department of Radiology, Box 357115, Seattle, WA (United States); Petscavage-Thomas, Jonelle M. [Penn State Hershey Medical Center, Department of Radiology, Hershey, PA (United States); Ha, Alice S. [University of Washington, Department of Radiology, Box 354755, Seattle, WA (United States)


    Total elbow arthroplasty (TEA) is becoming a popular alternative to arthrodesis for patients with end-stage elbow arthrosis and comminuted distal humeral fractures. Prior outcome studies have primarily focused on surgical findings. Our purpose is to determine the radiographic outcome of TEA and to correlate with clinical symptoms such as pain. This is an IRB-approved retrospective review from 2005 to 2015 of all patients with semiconstrained TEA. All available elbow radiographs and clinical data were reviewed. Data analysis included descriptive statistics and Kaplan-Meier survival curves for radiographic and clinical survival. A total of 104 total elbow arthroplasties in 102 patients were reviewed; 75 % were in women and the mean patient age was 63.1 years. Mean radiographic follow-up was 826 days with average of four radiographs per patient. Seventy TEAs (67 %) developed radiographic complications, including heterotopic ossification (48 %), perihardware lucency (27 %), periprosthetic fracture (23 %), hardware subluxation/dislocation (7 %), polyethylene wear (3 %), and hardware fracture/dislodgement (3 %); 56 patients (55 %) developed symptoms of elbow pain or instability and 30 patients (30 %) underwent at least one reoperation. In patients with radiographic complications, 66 % developed elbow pain, compared to 19 % of patients with no radiologic complications (p = 0.001). Of the patients with radiographic complications, 39 % had at least one additional surgery compared to 0 % of patients without radiographic complications (p = 0.056). Radiographic complications are common in patients after total elbow arthroplasty. There is a strong positive association between post-operative radiographic findings and clinical outcome. Knowledge of common postoperative radiographic findings is important for the practicing radiologist. (orig.)

  8. Current trends in total hip arthroplasty.

    Eingartner, Christoph


    After 20 years of application, with excellent short-term and long-term results, uncemented total hip arthroplasty (THA) is now generally regarded as the standard procedure for younger patients undergoing THA. However, expectations regarding hip replacement are continuously rising, along with the increasing number of young and active patients undergoing hip arthroplasty: a complication rate, including postoperative dislocation, close to zero, faster postoperative rehabilitation, low wear even in active patients, high durability and long term survival, etc. Demographic changes in aging societies are also leading to an increased need for cost-effective THA for the low-demand trauma patient. For high-demand patients, modern THA bearings, such as ceramic-ceramic articulations and other improved PE and metal materials, provide high durability and low wear, if the components are properly aligned. Navigation technology has been introduced in THA to ensure perfect component positioning without outliers and concomitant risk of increased wear and implant failure. Minimally and less invasive approaches are becoming increasingly popular in order to facilitate rehabilitation and fast-track surgery in younger patients. Navigation provides assistance for implant positioning in procedures with limited surgical exposure and visibility. New bone-preserving implants, such as surface replacement or short-stemmed femoral shaft prostheses, have been introduced especially for younger patients. Some of these new procedures are still under development,and the long-term results of new implant concepts have to be evaluated over the next decades. Not every modern concept will likely stand the test of time, but some will be beneficial for patients undergoing total hip arthroplasty in the future.

  9. Lower Limb Ischaemia Complicating Total Hip Arthroplasty

    Shiu-Wai Chan


    Full Text Available This article is about two patients having vascular injuries complicating total hip arthroplasty because of intraoperative indirect injuries. One patient had a delayed presentation of acute lower limb ischaemia, in which he required amputation of his left second toe because of ischaemic gangrene. The other patient had acute lower limb ischaemia leading to permanent muscle and nerve damage because of delayed recognition. Both patients had vascular interventions for the indirect vascular injuries. Preoperative workup for suspicious underlying peripheral vascular disease, intraoperative precautions, and perioperative period of vascular status monitoring are essential for prevention and early detection of such sinister events.

  10. Periprosthetic osteolysis after total wrist arthroplasty

    Boeckstyns, Michel E H; Herzberg, Guillaume


    Background and Literature Review Periprosthetic osteolysis (PPO) after second- or third-generation total wrist arthroplasty (TWA), with or without evident loosening of the implant components, has previously been reported in the literature, but rarely in a systematic way. Purpose The purpose....... Conclusion Periprosthetic loosening is frequent following a TWA. In our series it was not necessarily associated with implant loosening and seemed to stabilize within 3 years. Close and continued observation is, however, recommended. Level of Evidence Therapeutic IV....

  11. Anterior iliopsoas impingement after total hip arthroplasty.

    Trousdale, R T; Cabanela, M E; Berry, D J


    Pain after total hip arthroplasty (THA) can be caused by a multitude of conditions, including infection, aseptic loosening, heterotopic ossification, and referred pain. It is also recognized that soft tissue inflammation about the hip, such as trochanteric bursitis, can lead to hip pain after THA. Two cases of persistent iliopsoas tendinitis following THA are reported, which are believed to be caused by psoas tendon impingement against a malpositioned, uncemented, metal-backed acetabular component. The authors are unaware of previous reports of this problem, and suggest that the problem be considered in the differential diagnosis of groin pain following THA.

  12. Total Hip Arthroplasty in Mucopolysaccharidosis Type IH

    S. O'hEireamhoin


    Full Text Available Children affected by mucopolysaccharidosis (MPS type IH (Hurler Syndrome, an autosomal recessive metabolic disorder, are known to experience a range of musculoskeletal manifestations including spinal abnormalities, hand abnormalities, generalised joint stiffness, genu valgum, and hip dysplasia and avascular necrosis. Enzyme therapy, in the form of bone marrow transplantation, significantly increases life expectancy but does not prevent the development of the associated musculoskeletal disorders. We present the case of a 23-year-old woman with a diagnosis of Hurler syndrome with a satisfactory result following uncemented total hip arthroplasty.

  13. Postoperative pain treatment after total hip arthroplasty

    Højer Karlsen, Anders Peder; Geisler, Anja; Petersen, Pernille Lykke


    of this systematic review was to document the procedure-specific evidence for analgesic interventions after total hip arthroplasty (THA). This PRISMA-compliant and PROSPERO-registered review includes randomized placebo-controlled trials (RCTs) of medication-based analgesic interventions after THA. Endpoints were......, and lumbar plexus block reduced nausea and pruritus. The GRADE-rated quality of evidence ranged from low to very low throughout the analyses. This review demonstrated, that some analgesic interventions may have the capacity to reduce mean opioid requirements and/or mean pain intensity compared with controls...

  14. Gravitoturbulence in magnetised protostellar discs

    Riols, A


    Gravitational instability (GI) features in several aspects of protostellar disk evolution, most notably in angular momentum transport, fragmentation, and the outbursts exemplified by FU Ori and EX Lupi systems. The outer regions of protostellar discs may also be coupled to magnetic fields, which could then modify the development of GI. To understand the basic elements of their interaction, we perform local 2D ideal and resistive MHD simulations with an imposed toroidal field. In the regime of moderate plasma beta, we find that the system supports a hot gravito-turbulent state, characterised by considerable magnetic energy and stress and a surprisingly large Toomre parameter $Q~10$. This result has potential implications for disk structure, vertical thickness, ionisation, etc. Our simulations also reveal the existence of long-lived and dense `magnetic islands' or plasmoids. Lastly, we find that the presence of a magnetic field has little impact on the fragmentation criterion of the disk. Though our focus is on...

  15. Lumbar herniated disc: spontaneous regression

    Yüksel, Kasım Zafer


    Background Low back pain is a frequent condition that results in substantial disability and causes admission of patients to neurosurgery clinics. To evaluate and present the therapeutic outcomes in lumbar disc hernia (LDH) patients treated by means of a conservative approach, consisting of bed rest and medical therapy. Methods This retrospective cohort was carried out in the neurosurgery departments of hospitals in Kahramanmaraş city and 23 patients diagnosed with LDH at the levels of L3−L4, L4−L5 or L5−S1 were enrolled. Results The average age was 38.4 ± 8.0 and the chief complaint was low back pain and sciatica radiating to one or both lower extremities. Conservative treatment was administered. Neurological examination findings, durations of treatment and intervals until symptomatic recovery were recorded. Laségue tests and neurosensory examination revealed that mild neurological deficits existed in 16 of our patients. Previously, 5 patients had received physiotherapy and 7 patients had been on medical treatment. The number of patients with LDH at the level of L3−L4, L4−L5, and L5−S1 were 1, 13, and 9, respectively. All patients reported that they had benefit from medical treatment and bed rest, and radiologic improvement was observed simultaneously on MRI scans. The average duration until symptomatic recovery and/or regression of LDH symptoms was 13.6 ± 5.4 months (range: 5−22). Conclusions It should be kept in mind that lumbar disc hernias could regress with medical treatment and rest without surgery, and there should be an awareness that these patients could recover radiologically. This condition must be taken into account during decision making for surgical intervention in LDH patients devoid of indications for emergent surgery. PMID:28119770

  16. An Auto-Focusing Method in a Microscopic Testbed for Optical Discs.

    Tang, X; L'Hostis, P; Xiao, Y


    An auto-focusing method in a digital image system is demonstrated that uses a standard deviation of pixel gray levels as a feedback signal. In this system, an optical microscope and a charge coupled device (CCD) camera are used to create clear pit images of optical discs. A dynamic focusing scheme is designed in the system-control software, which is able to eliminate environmental disturbances and other noises so that a fast and stable focus can be achieved. The method shows an excellent focusing accuracy. The performance and possible applications of this method are discussed. The test results for optical discs are given in this paper.

  17. An improved rotating disc cathode cell for electrodeposition of actinides. The case of plutonium

    Becerril, V.A.; Tejera, R.A. (Inst. Nacional de Investigaciones Nucleares, Mexico City (Mexico)); Meas, V.Y. (Univ. Autonoma Metropolitana Iztapalapa, Area de Electroquimica, Mexico City (Mexico) CIDETEQ, Queretaro (Mexico)); Ozil, P. (CREMGP, ENSEEG, 38 - Saint Martin d' Heres (France))


    An electrolytic rotating disc electrode cell for electrodeposition of very thin and uniform plutonium (Pu) films with consistently high recoveries, was designed. It was made emphasizing the hydrodynamic conditions to be fulfilled by the device in agreement with the rotating disc electrode (RDE) model. The system was characterized by hydrodynamical parameters. The electrodeposition technique will be discussed elsewhere. The deposition yield was 97.5[+-]2.5%. The high quality of the very thin and uniform Pu deposits allowed one to obtain very suitable Pu sources (FWHM=10.8 keV, LM=100 and uniformity =10%) for alpha spectroscopy and for alpha emission probabilities and isotopic ratios studies. (orig.).

  18. Generation of highly inclined protoplanetary discs through single stellar flybys

    Xiang-Gruess, Meng


    We study the three-dimensional evolution of a viscous protoplanetary disc which is perturbed by a passing star on a parabolic orbit. The aim is to test whether a single stellar flyby is capable to excite significant disc inclinations which would favour the formation of so-called misaligned planets. We use smoothed particle hydrodynamics to study inclination, disc mass and angular momentum changes of the disc for passing stars with different masses. We explore different orbital configurations for the perturber's orbit to find the parameter spaces which allow significant disc inclination generation. Prograde inclined parabolic orbits are most destructive leading to significant disc mass and angular momentum loss. In the remaining disc, the final disc inclination is only below $20^\\circ$. This is due to the removal of disc particles which have experienced the strongest perturbing effects. Retrograde inclined parabolic orbits are less destructive and can generate disc inclinations up to $60^\\circ$. The final disc...

  19. Stellar irradiated discs and implications on migration of embedded planets II: accreting-discs

    Bitsch, Bertram; Lega, Elena; Crida, Aurélien


    The strength and direction of migration of embedded low mass planets depends on the disc's structure. It has been shown that, in discs with viscous heating and radiative transport, the migration can be directed outwards. In this paper we investigate the influence of a constant dM/dt-flux through the disc, as well as the influence of the disc's metallicity on the disc's thermodynamics. We focus on dM/dt discs, which have a net mass flux through them. Utilizing the resulting disc structure, we determine the regions of outward migration in the disc. We perform numerical hydrosimulations of dM/dt discs with viscous heating, radiative cooling and stellar irradiation in 2D in the r-z-plane. We use the explicit/implicit hydrodynamical code FARGOCA that includes a full tensor viscosity and stellar irradiation, as well as a two temperature solver that includes radiation transport in the flux-limited diffusion approximation. The migration of embedded planets is studied by using torque formulae. For a disc of gas surfac...

  20. Autologous adipose stem cells and polylactide discs in the replacement of the rabbit temporomandibular joint disc

    Ahtiainen, Katja; Mauno, Jari; Ellä, Ville; Hagström, Jaana; Lindqvist, Christian; Miettinen, Susanna; Ylikomi, Timo; Kellomäki, Minna; Seppänen, Riitta


    The temporomandibular joint (TMJ) disc lacks functional replacement after discectomy. We investigated tissue-engineered bilayer polylactide (PLA) discs and autologous adipose stem cells (ASCs) as a potential replacement for the TMJ disc. These ASC discs were pre-cultured either in control or in differentiation medium, including transforming growth factor (TGF)-β1 for one week. Prior to implantation, expression of fibrocartilaginous genes was measured by qRT-PCR. The control and differentiated ASC discs were implanted, respectively, in the right and left TMJs of rabbits for six (n = 5) and 12 months (n = 5). Thereafter, the excised TMJ areas were examined with cone beam computed tomography (CBCT) and histology. No signs of infection, inflammation or foreign body reactions were detected at histology, whereas chronic arthrosis and considerable condylar hypertrophy were observed in all operated joints at CBCT. The left condyle treated with the differentiated ASC discs appeared consistently smoother and more sclerotic than the right condyle. The ASC disc replacement resulted in dislocation and morphological changes in the rabbit TMJ. The ASC discs pre-treated with TGF-β1 enhanced the condylar integrity. While adverse tissue reactions were not shown, the authors suggest that with improved attachment and design, the PLA disc and biomaterial itself would hold potential for TMJ disc replacement. PMID:23720535

  1. The properties of discs around planets and brown dwarfs as evidence for disc fragmentation

    Stamatellos, Dimitris


    Direct imaging searches have revealed many very low-mass objects, including a small number of planetary mass objects, as wide-orbit companions to young stars. The formation mechanism of these objects remains uncertain. In this paper we present the predictions of the disc fragmentation model regarding the properties of the discs around such low-mass objects. We find that the discs around objects that have formed by fragmentation in discs hosted by Sun-like stars (referred to as 'parent' discs and 'parent' stars) are more massive than expected from the ${M}_{\\rm disc}-M_*$ relation (which is derived for stars with masses $M_*>0.2 {\\rm M}_{\\odot}$). Accordingly, the accretion rates onto these objects are also higher than expected from the $\\dot{M}_*-M_*$ relation. Moreover there is no significant correlation between the mass of the brown dwarf or planet with the mass of its disc nor with the accretion rate from the disc onto it. The discs around objects that form by disc fragmentation have larger than expected m...

  2. Autologous adipose stem cells and polylactide discs in the replacement of the rabbit temporomandibular joint disc.

    Ahtiainen, Katja; Mauno, Jari; Ellä, Ville; Hagström, Jaana; Lindqvist, Christian; Miettinen, Susanna; Ylikomi, Timo; Kellomäki, Minna; Seppänen, Riitta


    The temporomandibular joint (TMJ) disc lacks functional replacement after discectomy. We investigated tissue-engineered bilayer polylactide (PLA) discs and autologous adipose stem cells (ASCs) as a potential replacement for the TMJ disc. These ASC discs were pre-cultured either in control or in differentiation medium, including transforming growth factor (TGF)-β1 for one week. Prior to implantation, expression of fibrocartilaginous genes was measured by qRT-PCR. The control and differentiated ASC discs were implanted, respectively, in the right and left TMJs of rabbits for six (n = 5) and 12 months (n = 5). Thereafter, the excised TMJ areas were examined with cone beam computed tomography (CBCT) and histology. No signs of infection, inflammation or foreign body reactions were detected at histology, whereas chronic arthrosis and considerable condylar hypertrophy were observed in all operated joints at CBCT. The left condyle treated with the differentiated ASC discs appeared consistently smoother and more sclerotic than the right condyle. The ASC disc replacement resulted in dislocation and morphological changes in the rabbit TMJ. The ASC discs pre-treated with TGF-β1 enhanced the condylar integrity. While adverse tissue reactions were not shown, the authors suggest that with improved attachment and design, the PLA disc and biomaterial itself would hold potential for TMJ disc replacement.

  3. Minimizing cryopreservation-induced loss of disc cell activity for storage of whole intervertebral discs

    SCW Chan


    Full Text Available Severe intervertebral disc (IVD degeneration often requires disc excision and spinal fusion, which leads to loss of spinal segment mobility. Implantation of an allograft disc or tissue engineered disc construct emerges as an alternative to artificial disc replacement for preserving the motion of the degenerated level. Establishment of a bank of cadaveric or engineered cryopreserved discs enables size matching, and facilitates clinical management. However, there is a lack of understanding of the behaviour of disc cells during cryopreservation, as well as how to maximize their survival, such that disc graft properties can be preserved. Here, we report on the effect of alterations in cooling rates, cryoprotective agents (CPAs, and duration of pre-cryopreservation incubation in CPA on cellular activity in whole porcine lumbar discs. Our results indicated that cooling rates of -0.3°C/min and -0.5°C /min resulted in the least loss of metabolic activity in nucleus pulposus (NP and annulus fibrosus (AF respectively, while metabolic activity is best maintained by using a combination of 10% dimethylsulphoxide (DMSO and 10% propylene-glycol (PG as CPA. By the use of such parameters, metabolic activity of the NP and the AF cells could be maintained at 70% and 45%, respectively, of that of the fresh tissue. Mechanical testing and histological evaluation showed no significant differences in mechanical properties or alterations in disc structure compared to fresh discs. Despite the limitations of the animal model, our findings provide a framework for establishing an applicable cryopreservation protocol for human disc allografts or tissue-engineered disc constructs.

  4. Migration and kinematics in growing disc galaxies with thin and thick discs

    Aumer, Michael; Binney, James; Schönrich, Ralph


    We analyse disc heating and radial migration in N-body models of growing disc galaxies with thick and thin discs. Similar to thin-disc-only models, galaxies with appropriate non-axisymmetric structures reproduce observational constraints on radial disc heating in and migration to the Solar Neighbourhood (Snhd). The presence of thick discs can suppress non-axisymmetries and thus higher baryonic-to-dark matter fractions are required than in models that only have a thin disc. Models that are baryon dominated to roughly the Solar radius R0 are favoured, in agreement with data for the Milky Way. For inside-out growing discs, today's thick-disc stars at R0 are dominated by outwards migrators. Whether outwards migrators are vertically hotter than non-migrators depends on the radial gradient of the thick-disc vertical velocity dispersion. There is an effective upper boundary in angular momentum that thick-disc stars born in the centre of a galaxy can reach by migration, which explains the fading of the high [α/Fe] sequence outside R0. Our models compare well to Snhd kinematics from Radial Velocity Survey and Tycho-Gaia Astrometric Solution data. For such comparisons, it is important to take into account the azimuthal variation of kinematics at R ∼ R0 and biases from survey selection functions. The vertical heating of thin-disc stars by giant molecular clouds is only mildly affected by the presence of thick discs. Our models predict higher vertical velocity dispersions for the oldest stars than found in the Snhd age velocity dispersion relation, possibly because of measurement uncertainties or an underestimation of the number of old cold stars in our models.

  5. Structure of radiation dominated gravitoturbulent quasar discs

    Shadmehri, Mohsen; Dib, Sami


    Self-gravitating accretion discs in a gravitoturbulent state, including radiation and gas pressures, are studied using a set of new analytical solutions. While the Toomre parameter of the disc remains close to its critical value for the onset of gravitational instability, the dimensionless stress parameter is uniquely determined from the thermal energy reservoir of the disc and its cooling rate. Our solutions are applicable to the accretion discs with dynamically important radiation pressure like in the quasars discs. We show that physical quantities of a gravitoturbulent disc in the presence of radiation are significantly modified compared to solutions with only gas pressure. We show that the dimensionless stress parameter is an increasing function of the radial distance so that its steepness strongly depends on the accretion rate. In a disc without radiation its slope is 4.5, however, we show that in the presence of radiation, it varies between 2 and 4.5 depending on the accretion rate and the central mass....

  6. Chemical separation of disc components using RAVE

    Wojno, Jennifer; Steinmetz, Matthias; McMillan, Paul J; Matijevič, Gal; Binney, James; Wyse, Rosemary F G; Boeche, Corrado; Just, Andreas; Grebel, Eva K; Siebert, Arnaud; Bienaymé, Olivier; Gibson, Brad K; Zwitter, Tomaž; Bland-Hawthorn, Joss; Navarro, Julio F; Parker, Quentin A; Reid, Warren; Seabroke, George; Watson, Fred


    We present evidence from the RAdial Velocity Experiment (RAVE) survey of chemically separated, kinematically distinct disc components in the solar neighbourhood. We apply probabilistic chemical selection criteria to separate our sample into $\\alpha$-low (`thin disc') and $\\alpha$-high (`thick disc') components. Using newly derived distances, which will be utilized in the upcoming RAVE DR5, we explore the kinematic trends as a function of metallicity for each of the disc components. For our thin disc stars, we find a negative trend in the mean rotational velocity ($V_{\\mathrm{\\phi}}$) as a function of iron abundance ([Fe/H]). We measure a positive trend in $\\partial V_{\\mathrm{\\phi}}$/$\\partial$[Fe/H] for the thick disc, consistent with results from high-resolution surveys. We also find differences between the chemical thin and thick discs in all three components of velocity dispersion. We discuss the implications of an $\\alpha$-low, metal-rich population originating from the inner Galaxy, where the orbits of ...

  7. Have proto-planetary discs formed planets?

    Greaves, J S


    It has recently been noted that many discs around T Tauri stars appear to comprise only a few Jupiter-masses of gas and dust. Using millimetre surveys of discs within six local star-formation regions, we confirm this result, and find that only a few percent of young stars have enough circumstellar material to build gas giant planets, in standard core accretion models. Since the frequency of observed exo-planets is greater than this, there is a `missing mass' problem. As alternatives to simply adjusting the conversion of dust-flux to disc mass, we investigate three other classes of solution. Migration of planets could hypothetically sweep up the disc mass reservoir more efficiently, but trends in multi-planet systems do not support such a model, and theoretical models suggest that the gas accretion timescale is too short for migration to sweep the disc. Enhanced inner-disc mass reservoirs are possible, agreeing with predictions of disc evolution through self-gravity, but not adding to millimetre dust-flux as t...

  8. Stem cells sources for intervertebral disc regeneration

    Gianluca; Vadalà; Fabrizio; Russo; Luca; Ambrosio; Mattia; Loppini; Vincenzo; Denaro


    Intervertebral disc regeneration field is rapidly growing since disc disorders represent a major health problem in industrialized countries with very few possible treatments.Indeed, current available therapies are symptomatic, and surgical procedures consist in disc removal and spinal fusion, which is not immune to regardable concerns about possible comorbidities, cost-effectiveness, secondary risks and long-lasting outcomes. This review paper aims to share recent advances in stem cell therapy for the treatment of intervertebral disc degeneration. In literature the potential use of different adult stem cells for intervertebral disc regeneration has already been reported. Bone marrow mesenchymal stromal/stem cells, adipose tissue derived stem cells, synovial stem cells, muscle-derived stem cells, olfactory neural stem cells, induced pluripotent stem cells, hematopoietic stem cells, disc stem cells, and embryonic stem cells have been studied for this purpose either in vitro or in vivo. Moreover, several engineered carriers(e.g., hydrogels), characterized by full biocompatibility and prompt biodegradation, have been designed and combined with different stem cell types in order to optimize the local and controlled delivery of cellular substrates in situ. The paper overviews the literature discussing the current status of our knowledge of the different stem cells types used as a cell-based therapy for disc regeneration.

  9. Optically-thick accretion discs with advection

    陈林红; 吴枚; 尚仁成


    The structures of optically-thick accretion discs with radial advection have been investigated by the iteration and integration algorithms. The advective cooling term changes mostly the inner part of disc solution, and even results in an optically-thick advection-dominated accretion flow (ADAF). Three distinct branches-the outer Shakura-Sunyaev disc (SSD), the inner ADAF and the middle transition layer-are found for a super-Eddington disc. The SSD-ADAF transition radius can be estimated as 18(M/ME)RG where RG is the Schwarzschild radius, M is the mass accretion rate and ME is the Eddington accretion rate. SSD solutions calculated with the iteration and integration methods are identical, while ADAF solutions obtained by these two methods differ greatly. Detailed algorithms and their differences have been analysed. The iteration algorithm is not self-consistent, since it implies that the dimensionless advection factor ξ is invariant, but in the inner ADAF region the variation of ξ is not negligible. The integration algorithm is always effective for the whole region of an optically-thick disc if the accretion rate is no smaller than 10-4ME. For optically-thin discs, the validity of these two algorithms is different. We suggest that the integration method be employed to calculate the global solution of a disc model without assuming ξ to be a constant. We also discuss its application to the emergent continuum spectrum in order to explain observational facts.

  10. The tidal disruption of protoplanetary accretion discs

    Larwood, J D


    In this paper we revisit the problem of the tidal interaction occuring between a protostellar accretion disc and a secondary point mass following a parabolic trajectory. We model the disc response analytically and we compare our results with three-dimensional SPH simulations. Inviscid as well as viscous hydrodynamics is considered. We show that in a viscous system the response derived from inviscid considerations is predominant even for the highest estimates of an anomalous disc shear viscosity. The angular momentum lost from the disc during the encounter is derived from linear theory, for distant fly-bys, as well as the changes to the disc orientation expected in non-coplanar encounters. It is shown that the target discs can become warped and precess by a small amount during non-coplanar encounters. This small precession is shown to give rise to a relative tilt of the disc which is always more important for determining its final orientation than is the change to the orbital inclination. We discuss the implic...

  11. Intradiscal pressure measurements in normal discs, compressed discs and compressed discs treated with axial posterior disc distraction: an experimental study on the rabbit lumbar spine model.

    Guehring, Thorsten; Unglaub, Frank; Lorenz, Helga; Omlor, Georg; Wilke, Hans-Joachim; Kroeber, Markus W


    Intervertebral disc (IVD) pressure measurement is an appropriate method for characterizing spinal loading conditions. However, there is no human or animal model that provides sufficient IVD pressure data. The aim of our study was to establish physiological pressure values in the rabbit lumbar spine and to determine whether temporary external disc compression and distraction were associated with pressure changes. Measurements were done using a microstructure-based fibreoptic sensor. Data were collected in five control rabbits (N, measurement lying prone at segment L3/4 at day 28), five rabbits with 28 days of axial compression (C, measurement at day 28) and three rabbits with 28 days of axial compression and following 28 days of axial distraction (D, measurement at day 56). Disc compression and distraction was verified by disc height in lateral radiographs. The controls (N) showed a level-related range between 0.25 MPa-0.45 MPa. The IVD pressure was highest at level L3/4 (0.42 MPa; range 0.38-0.45) with a decrease in both cranial and caudal adjacent segments. The result for C was a significant decrease in IVD pressure (0.31 MPa) when compared with controls (P=0.009). D showed slightly higher median IVD pressure (0.32 MPa) compared to C, but significantly lower levels when compared with N (P=0.037). Our results indicate a high range of physiological IVD pressure at different levels of the lumbar rabbit spine. Temporary disc compression reduces pressure when compared with controls. These data support the hypothesis that temporary external compression leads to moderate disc degeneration as a result of degradation of water-binding disc matrix or affected active pumping mechanisms of nutrients into the disc. A stabilization of IVD pressure in discs treated with temporary distraction was observed.

  12. Endoscopic anterior decompression in cervical disc disease

    Yad Ram Yadav


    Full Text Available Background: Although microscopic anterior cervical discectomy with or without fusion are common surgical procedures for treatment of cervical herniated discs, loss of disc height, pseudarthrosis, and adjacent disc degeneration are some of the problems associated with it. This study is aimed to evaluate results of endoscopic microforaminotomy in cervical disc diseases. Materials and Methods: A prospective study of 50 patients of mono segmental soft or hard disc causing myeloradiculopathy was undertaken. A visual analogue scale (VAS for neck and arm pain and functional outcomes using the Nurick grading system were assessed. There were 28, 12, 8, and 2 patients at C5-6, C6-7, C4-5, and C3-4 levels disc diseases, respectively. Patients with two or more level disc, instabilities, disc extending more than half vertebral body height, and previous operation at the same segment were excluded. Results: Age ranged from 21 to 67 years. Average postoperative reduction in disc height, operating time, and blood loss was 1.1 mm, 110 minutes, and 30 ml, respectively. Average pre-operative VAS score for arm pain and Nurick grading was 7.6 and 2.7, which improved to 1.9 and 0.82, respectively. All patients improved; 1, 2, 3 grade improvement was seen in 10, 27, and 10 patients, respectively. There was no significant complication or any mortality. Conclusion: Although longer follow up of large number of patients is required, endoscopic microforaminotomy is a safe and an effective alternative to microscopic anterior discectomy with or without fusion.

  13. The efficacy of continuous passive motion after total knee arthroplasty: a comparison of three protocols.

    Boese, C Kent; Weis, Marcia; Phillips, Tamra; Lawton-Peters, Sheila; Gallo, Theresa; Centeno, Leslie


    We conducted a randomized, controlled trial to determine the efficacy of CPM following total knee arthroplasty (TKA). Postoperative outcomes of interest were: swelling, drop in hemoglobin, self-reported pain scores, range of motion, and hospital length of stay. A total of 160 subjects were randomized into one of three treatment groups: CPM device on and moving from the immediate post-operative period, CPM device on and stationary at 90 degree flexion for the first night and then moving throughout the rest of their stay, and no CPM (N = 55, 51, and 54, respectfully). Subjects were followed during the first and second postoperative day until their first follow-up appointment approximately 3-4 weeks post-operatively. Cost of CPM was further evaluated. CPM provided no benefit to patients recovering from TKA. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. [Computer-assisted total knee arthroplasty: 12 years experience in Grenoble].

    Saragaglia, Dominique


    Computer-assisted total knee arthroplasty was developed in Grenoble in the mid-1990s. The first human implantation was performed on 21 January 1997, with no particular problems. Since this date more than 200,000 patients have been implanted with our device all over the world. The device is passive (not active like a robot), and requires no pre- or perioperative imaging. It is based on kinematics and palpation, the surgeon remaining in charge at all times. The computer helps to identify the lower leg axis, to accurately fix the bone cutting guides, and to check the ligament balance. These steps are not easy to perform with conventional ancillaries. The effectiveness of computer-assisted total knee replacement is well documented, although it is too early to claim that a "well-aligned" prothesis will have a better survival rate. Long-term follow-up studies are needed, with modern prostheses, to confirm the results of historical studies.

  15. Spectroscopic Parameters of Lumbar Intervertebral Disc Material

    Terbetas, G.; Kozlovskaja, A.; Varanius, D.; Graziene, V.; Vaitkus, J.; Vaitkuviene, A.


    There are numerous methods of investigating intervertebral disc. Visualization methods are widely used in clinical practice. Histological, imunohistochemical and biochemical methods are more used in scientific research. We propose that a new spectroscopic investigation would be useful in determining intervertebral disc material, especially when no histological specimens are available. Purpose: to determine spectroscopic parameters of intervertebral disc material; to determine emission spectra common for all intervertebral discs; to create a background for further spectroscopic investigation where no histological specimen will be available. Material and Methods: 20 patients, 68 frozen sections of 20 μm thickness from operatively removed intervertebral disc hernia were excited by Nd:YAG microlaser STA-01-TH third harmonic 355 nm light throw 0, 1 mm fiber. Spectrophotometer OceanOptics USB2000 was used for spectra collection. Mathematical analysis of spectra was performed by ORIGIN multiple Gaussian peaks analysis. Results: In each specimen of disc hernia were found distinct maximal spectral peaks of 4 types supporting the histological evaluation of mixture content of the hernia. Fluorescence in the spectral regions 370-700 nm was detected in the disc hernias. The main spectral component was at 494 nm and the contribution of the components with the peak wavelength values at 388 nm, 412 nm and 435±5 nm were varying in the different groups of samples. In comparison to average spectrum of all cases, there are 4 groups of different spectral signatures in the region 400-500 nm in the patient groups, supporting a clinical data on different clinical features of the patients. Discussion and Conclusion: besides the classical open discectomy, new minimally invasive techniques of treating intervertebral disc emerge (PLDD). Intervertebral disc in these techniques is assessed by needle, no histological specimen is taken. Spectroscopic investigation via fiber optics through the

  16. Groups, cacti and framed little discs

    Hepworth, Richard


    Let G be a topological group. Then the based loopspace of G is an algebra over the cacti operad, while the double loopspace of the classifying space of G is an algebra over the framed little discs operad. This paper shows that these two algebras are equivalent, in the sense that they are weakly equivalent E-algebras, where E is an operad weakly equivalent to both framed little discs and cacti. We recover the equivalence between cacti and framed little discs, and Menichi's isomorphism between the BV-algebras obtained by taking the homology of the loopspace of G and of the double loopspace of BG.

  17. A lumbar disc surgery predictive score card.

    Finneson, B E


    A lumbar disc surgery predictive score card or questionnaire has been developed to assess potential candidates for excision of a herniated lumbar disc who have not previously undergone lumbar spine surgery. It is not designed to encompass patients who are being considered for other types of lumbar spine surgery, such as decompressive laminectomy or fusion. In an effort to make the "score card" usable by almost all physicians who are involved in lumbar disc surgery, only studies which have broad acceptance and are generally employed are included. Studies which have less widespread use such as electromyogram, discogram, venogram, special psychologic studies (MMPI, pain drawings) have been purposely excluded.

  18. Extensor mechanism allograft in total knee arthroplasty

    Helito, Camilo Partezani; Gobbi, Riccardo Gomes; Tozi, Mateus Ramos; Félix, Alessandro Monterroso; Angelini, Fábio Janson; Pécora, José Ricardo


    Objective To analyze the experience with allograft transplantation of the extensor mechanism in total knee arthroplasty and compare results with the international experience. Methods We retrospectively evaluated three cases of extensor mechanism allograft after total knee arthroplasty performed in our hospital with the aid of one of the few tissue banks in Brazil and attempt to establish whether our experiences were similar to others reported in the world literature regarding patient indication, techniques, and outcomes. Results Two cases went well with the adopted procedure, and one case showed bad results and progressed to amputation. As shown in the literature, the adequate tension of the graft, appropriate tibial fixation and especially the adequate patient selection are the better predictors of good outcomes. Previous chronic infection can be an unfavorable predictor. Conclusion This surgical procedure has precise indication, albeit uncommon, either because of the rarity of the problem or because of the low availability of allografts, due to the scarcity of tissue banks in Brazil. Level of Evidence IV, Case Series. PMID:24453688

  19. UnconStrained ShoUlder arthroplasty


    Objective: To evaluate the results of 36unconstrained shoulder arthroplasties. Methods: In the series, 24 total and 12 hemiarthroplasties of the shoulders were performed with unconstrained shoulder prostheses in 29 patients who suffered from glenohumeral degenerative arthritis, rheumatoid arthritis, avascular necrosis and proximal fracture of humerus, respectively. Follow-up averaged 6.2years. All patients were evaluated pre- and post-operatively using the rating system of the Society of American Shoulder and Elbow Surgeons which assesses the severity of pain,strength of muscles around shoulder, stability, range of motion and functional activities of daily living. Radiolucent line and migration of prostheses were observed postoperatively on X-rays. Results: Postoperatively, the rate of pain relief was 91.3%, and active range of motion increased by 47° inforward flexion, 43° in abduction , 30° in external rotation,and 4 segments in internal rotation. Preoperatively the average points of 6 functional activities patients could perform was 0.8, and postoperatively 3.1. On postoperative X-ray, proximal migration of the humerus was seen in 8 shoulders, 6 of which had either a torn or absent rotator cuff. Radiolucent lines were seen around 1humeral component and 9 glenoid components. Onehumeral and 2 glenoid components loosened. Conclusions: These results suggest that unconstrained shoulder arthroplasty is a satisfactory and safe technique.

  20. Wedged tibial components for total knee arthroplasty.

    Jeffery, R S; Orton, M A; Denham, R A


    Severe coronal deformity of the knee is frequently associated with erosion of one tibial condyle. This can cause problems with fixation and alignment during total knee arthroplasty. If the tibia is cut to the level of the more worn side, valuable bone is sacrificed; if the less worn side is chosen, the deficiency must be filled with bone--graft, cement, or a prosthesis. Tibial components with an integral polyethylene wedge on the undersurface were introduced in 1980 for use in patients with a bony deficit on one tibial condyle. The authors believe that the Denham prosthesis (Biomet, Wales, U.K.) was the first knee arthroplasty to offer such spacers. Twenty-six patients with preoperative varus deformity in whom a wedged component was used were compared with 29 historic control subjects. None of the wedged components loosened after a median follow-up period of 8 years compared with loosening in five of the control subjects (P = .01). In three of the control subjects a fractured triangle of cement was present on the radiographs. Use of the wedges was not accompanied by an improvement in postoperative alignment. The authors conclude that the wedges resulted in improved fixation that was independent of postoperative alignment.

  1. Radiographic analysis of shoulder anatomical arthroplasty

    Merolla, Giovanni [Unit of Shoulder and Elbow Surgery, ' D. Cervesi' Hospital, L. Van Beethoven 46 Street, 47841 Cattolica (Italy)], E-mail:; Di Pietto, Francesco; Romano, Stefania [Department of Diagnostic Imaging, ' A. Cardarelli' Hospital, Naples (Italy); Paladini, Paolo; Campi, Fabrizio; Porcellini, Giuseppe [Unit of Shoulder and Elbow Surgery, ' D. Cervesi' Hospital, L. Van Beethoven 46 Street, 47841 Cattolica (Italy)


    Arthroplasty is the standard treatment for advanced shoulder osteoarthritis. Modern prostheses designs have modular features whose size, shaft/head and body morphology can be adjusted. Total Shoulder Arthroplasty (TSA) provides better results. A complete X-ray follow-up is essential to assess the results and evaluate the survival rates of a shoulder prosthesis. Antero-posterior at 40 deg. in both internal and external rotation (true AP view) and axillary view are recommended to assess the following parameters: orientation and translation of the humeral component, offset, size and height of the humeral head, acromio-humeral distance, distribution and fixation of the cement, stress shielding and cortical resorption, radiolucent lines, subsidence and tilt, glenoid wear and 'bone stock', prostheses instability, glenoid component shift. Shoulder hemiarthroplasty can lead to glenoid wear; the true AP film at 40 deg. of internal rotation provides the best profile of gleno-humeral joint to depict glenoid erosion. Shift of the glenoid component in TSA is identified as tilting or medial migration on true AP and axillary views in the early postoperative period (1-2 months) and at minimum of 2 years. An exhaustive radiographic analysis remains essential to monitor the prosthetic implant and detect early and late complications or risk factors of prosthetic loosening.

  2. Arthrofibrosis Associated With Total Knee Arthroplasty.

    Cheuy, Victor A; Foran, Jared R H; Paxton, Roger J; Bade, Michael J; Zeni, Joseph A; Stevens-Lapsley, Jennifer E


    Arthrofibrosis is a debilitating postoperative complication of total knee arthroplasty (TKA). It is one of the leading causes of hospital readmission and a predominant reason for TKA failure. The prevalence of arthrofibrosis will increase as the annual incidence of TKA in the United States rises into the millions. In a narrative review of the literature, the etiology, economic burden, treatment strategies, and future research directions of arthrofibrosis after TKA are examined. Characterized by excessive proliferation of scar tissue during an impaired wound healing response, arthrofibrotic stiffness causes functional deficits in activities of daily living. Postoperative, supervised physiotherapy remains the first line of defense against the development of arthrofibrosis. Also, adjuncts to traditional physiotherapy such as splinting and augmented soft tissue mobilization can be beneficial. The effectiveness of rehabilitation on functional outcomes depends on the appropriate timing, intensity, and progression of the program, accounting for the patient's ability and level of pain. Invasive treatments such as manipulation under anesthesia, debridement, and revision arthroplasty improve range of motion, but can be traumatic and costly. Future studies investigating novel treatments, early diagnosis, and potential preoperative screening for risk of arthrofibrosis will help target those patients who will need additional attention and tailored rehabilitation to improve TKA outcomes. Arthrofibrosis is a multi-faceted complication of TKA, and is difficult to treat without an early, tailored, comprehensive rehabilitation program. Understanding the risk factors for its development and the benefits and shortcomings of various interventions are essential to best restore mobility and function. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Stellar irradiated discs and implications on migration of embedded planets I: equilibrium discs

    Bitsch, Bertram; Morbidelli, Alessandro; Kley, Willy; Dobbs-Dixon, Ian


    The strength and direction of migration of low mass planets depends on the disc's thermodynamics. In discs where the viscous heating is balanced by radiative transport, the migration can be directed outwards, a process which extends the lifetime of growing planetary embryos. We investigate the influence of opacity and stellar irradiation on the disc thermodynamics. Utilizing the resulting disc structure, we determine the regions of outward migration. We perform two-dimensional numerical simulations of equilibrium discs with viscous heating, radiative cooling and stellar irradiation. We use the hydrodynamical code NIRVANA that includes a full tensor viscosity and stellar irradiation, as well as a two temperature solver that includes radiation transport in the flux-limited diffusion approximation. The migration is studied by using torque formulae. In the constant opacity case, we reproduce the analytical results of a black-body disc: the stellar irradiation dominates in the outer regions -- leading to flaring -...

  4. Investigation of the coatings applied onto brake discs on disc-brake pad pair

    I. Kiliçaslan


    Full Text Available While braking, according to the severity of it, thermal, metallurgical, constructive and tribological occurrences emerge on the brake disc-pad interface. In this study, NiCr was sprayed as bonding layer onto the discs, one ofwhich was coated with Al2O3-TiO2 by plasma spray and the other was coated with NiCr-Cr3C2 by High Velocity Oxygen Fuel (HVOF. In addition, the discs were tested with inertia dynamometer according to SAE’s J2522 testing procedure. The measurements showed that although the pads of the coated discs were exposed to higher braking temperatures, friction coefficient of the disc coated with NiCr- Cr3C2 was obtained 6 % higher compared to the original disc.

  5. Total knee arthroplasty in patients with a previous patellectomy.

    Maslow, Jed; Zuckerman, Joseph D; Immerman, Igor


    Post-patellectomy patients represent a specific subgroup of patients that may develop arthritis and persistent knee pain and potentially require treatment with total knee arthroplasty. This article reviews the treatment and functional outcomes following total knee arthroplasty in patients with prior patellectomy. A case report is presented as an example of the clinical management of a post-patellectomy patient with significant knee pain and disability treated with total knee arthroplasty. Emphasis will be placed in decision- making, specifically with the use of a posterior stabilized implant. In addition, postoperative strengthening of the quadriceps is essential to compensate for the lack of the patella and increase the success of total knee arthroplasty in this subgroup of patients.

  6. Recurrent Hemarthrosis Following Knee Arthroplasty Treated with Arterial Embolization.

    Weidner, Zachary D; Hamilton, William G; Smirniotopoulos, John; Bagla, Sandeep


    Recurrent hemarthrosis is an uncommon but troublesome complication following knee arthroplasty. This study reports the results for 13 patients with spontaneous recurrent hemarthrosis after knee arthroplasty treated with arterial embolization. The average interval between arthroplasty and embolization was 47 months (range, 2-103 months), and the average time from onset of hemarthrosis to embolization was 4.1 months (range, 1-11 months). Geniculate arterial embolization lead to resolution of hemarthrosis in 12 of 13 patients (92.3%). The one clinical failure likely represented a case of misdiagnosed periprosthetic joint infection. Two patients experienced transient cutaneous ischemia related to distal particulate embolization that resolved spontaneously. Selective geniculate arterial embolization is an effective and safe treatment modality for recurrent hemarthrosis after knee arthroplasty.

  7. Reverse Shoulder Arthroplasty for Trauma: When, Where, and How.

    Szerlip, Benjamin W; Morris, Brent J; Edwards, T Bradley


    Reverse shoulder arthroplasty has become increasingly popular for the treatment of complex shoulder injuries, including proximal humerus fractures and fixed glenohumeral dislocation, in the elderly population. The early to midterm results of reverse shoulder arthroplasty for the treatment of proximal humerus fractures are promising compared with the results of unconstrained humeral head replacement, and patients may have more predictable improvement with less dependence on bone healing and rehabilitation. However, long-term follow-up is needed, and surgeons must be familiar with various complications that are specific to reverse shoulder arthroplasty. To achieve optimal patient outcomes for the management of traumatic shoulder injuries, surgeons must have a comprehensive understanding of the current implant options, indications, and surgical techniques for reverse shoulder arthroplasty.

  8. Alpine Skiing With total knee ArthroPlasty (ASWAP)

    Narici, Marco; Conte, M; Salvioli, Stefano


    This study investigated features of skeletal muscle ageing in elderly individuals having previously undergone unilateral total knee arthroplasty (TKA) and whether markers of sarcopenia could be mitigated by a 12-week alpine skiing intervention. Novel biomarkers agrin, indicative of neuromuscular ...

  9. The Optimal Analgesic Block for Total Knee Arthroplasty

    Bendtsen, Thomas Fichtner; Moriggl, Bernhard; Chan, Vincent W


    Peripheral nerve block for total knee arthroplasty is ideally motor sparing while providing effective postoperative analgesia. To achieve these goals, one must understand surgical dissection techniques, distribution of nociceptive generators, sensory innervation of the knee, and nerve topography ...

  10. Myofascial Pain in Patients Waitlisted for Total Knee Arthroplasty

    Richard Henry


    Full Text Available BACKGROUND: Knee pain is one of the major sources of pain and disability in developed countries, particularly in aging populations, and is the primary indication for total knee arthroplasty (TKA in patients with osteoarthritis (OA.

  11. Is cold therapy really efficient after knee arthroplasty?

    Ersin Kuyucu


    Conclusion: After knee arthroplasty, the preoperative and postoperative use of cryotherapy is effective in terms of the pain control and functional knee scores without a significant change in surgical blood loss.

  12. Primary versus secondary distal femoral arthroplasty for treatment of total knee arthroplasty periprosthetic femur fractures.

    Chen, Antonia F; Choi, Lisa E; Colman, Matthew W; Goodman, Mark A; Crossett, Lawrence S; Tarkin, Ivan S; McGough, Richard L


    Current methods of fixing periprosthetic fractures after total knee arthroplasty (TKA) are variable, and include open reduction and internal fixation (ORIF) via plating, retrograde nailing, or revision using standard revision TKA components or a distal femoral arthroplasty (DFA). The purpose of this study is to compare patients who failed plating techniques requiring subsequent revision to DFA to patients who underwent primary DFA. Of the 13 patients (9.2%) who failed primary ORIF, causes included nonunion (53.8%), infection (30.8%), loosening (7.7%), and refracture (7.7%). There were significantly more surgical procedures for ORIF revision to DFA compared to primary DFA. Complications for patients who underwent primary reconstruction with DFAs included extensor mechanism disruption (8.3%), infection (5.6%), and dislocation (2.8%). Primary reconstruction via ORIF is beneficial for preserving bone stock, but primary DFA may be preferred in osteopenic patients, or those at high risk for nonunion.

  13. Burned-out discs stop hurting: fact or fiction?

    Bendix, Tom; Kjaer, Per; Korsholm, Lars


    ). The risk for LBP during the past year attributed to black discs was 11%. CONCLUSION: The data could not support the hypothesis that severely degenerated discs are "burned out" and become less painful. People with black discs had a higher prevalence of LBP compared to those with grey or normal discs...

  14. Medium-term outcomes of artificial disc replacement for severe cervical disc narrowing

    Chao-Hung Yeh; Che-Wei Hung; Cheng-Hsing Kao; Chien-Ming Chao


    Objective:To determine if theBryan cervical disc prosthesis could relieve objective neurological symptoms, signs, and restore mobility in patients with severe cervical disc narrowing. Methods:Clinical data of thirty-two patients underwentBryan cervical disc replacement has been collected fromApril2006 toFebruary2010.Severe cervical disc narrowing with gradeV disc degeneration were included in this study.Bryan cervical disc prostheses have been implanted through anterior approach.JapaneseOrthopedicsAssociation(JOA) score, visual analog scale, Odom’s scale, and flexion-extension radiological follow-ups were applied for evaluations. Results:A total of41Bryan disc prostheses from32 patients with an average follow-up duration of33.5 months(range23 to44 months) were evaluated.Clinical functions of patients were significantly improved.Preoperative averaged visual analog scale score of6.3±2.2 was decreased to1.3±1.2(at36 months,P<0.001), while preoperative averagedJOA score of14.4±1.2 was increased to16.3±0.9(at36 months,P<0.001).Thirty of32 patients received excellent to good outcomes inOdom’s scale.Averaged mobility was restored to(9.9±3.2)°at the last follow-up evaluation of36 months.No subsidence or migration of implant was identified. Conclusions:Acceptable clinical outcome for treatment of severe cervical disc narrowing with cervical disc replacement technique has been performed in current study.Most patients maintained good postoperative mobility and no significant adjacent level degeneration were found.Cervical disc replacement may be applicable in treatment of severe cervical disc narrowing; however, longer follow-ups are required for ensuring the long-term efficacy of cervical disc replacement.

  15. Preoperative Patient Education for Hip and Knee Arthroplasty: Financial Benefit?

    Tait, Mark A; Dredge, Carter; Barnes, C Lowry


    Of 904 patients who underwent primary total knee arthroplasty (TKA) and total hip arthroplasty (THA) at the same hospital, 802 participated in a preoperative education day called "Joint Academy" (JA). The length of stay of JA participants was 2.12 days (49.5%) less than patients who did not attend a JA (p education program may significantly reduce overall costs for primary TKA and THA procedures.

  16. Association between trochanteric bursitis, osteoarthrosis and total hip arthroplasty,

    Carlos Roberto Schwartsmann; Felipe Loss; Leandro de Freitas Spinelli; Roque Furian; Marcelo Faria Silva; Júlia Mazzuchello Zanatta; Leonardo Carbonera Boschin; Ramiro Zilles Gonçalves; Anthony Kerbes Yépez


    OBJECTIVE: this was an epidemiological study on trochanteric bursitis at the time of performing total hip arthroplasty.METHODS: sixty-two sequential patients who underwent total hip arthroplasty due to osteoarthrosis, without any previous history of trochanteric bursitis, were evaluated. The bursas were collected and evaluated histologically.RESULTS: there were 35 female patients (56.5%) and 27 male patients (43.5%), with a mean age of 65 years (±11). Trochanteric bursitis was conformed histo...

  17. Readmissions after fast-track hip and knee arthroplasty

    Husted, Henrik; Otte, Niels Kristian Stahl; Kristensen, Billy B


    With the implementation of fast-track surgery with optimization of both logistical and clinical features, the postoperative convalescence has been reduced as functional milestones have been achieved earlier and consequently length of stay (LOS) in hospital has been reduced. However, it has been s...... speculated that a decrease in LOS may be associated with an increase in readmissions in general, including risk of dislocation after total hip arthroplasty (THA) or manipulation after total knee arthroplasty (TKA)....

  18. Axial T2* mapping in intervertebral discs: a new technique for assessment of intervertebral disc degeneration

    Hoppe, Sven; Quirbach, Sebastian; Krause, Fabian G.; Benneker, Lorin M. [Inselspital, Berne University Hospital, Department of Orthopaedic Surgery, Berne (Switzerland); Mamisch, Tallal C. [Inselspital, Berne University Hospital, Department of Radiology, Berne (Switzerland); Werlen, Stefan [Clinic Sonnenhof, Department of Radiology, Berne (Switzerland)


    To demonstrate the potential benefits of biochemical axial T2* mapping of intervertebral discs (IVDs) regarding the detection and grading of early stages of degenerative disc disease using 1.5-Tesla magnetic resonance imaging (MRI) in a clinical setting. Ninety-three patients suffering from lumbar spine problems were examined using standard MRI protocols including an axial T2* mapping protocol. All discs were classified morphologically and grouped as ''healthy'' or ''abnormal''. Differences between groups were analysed regarding to the specific T2* pattern at different regions of interest (ROIs). Healthy intervertebral discs revealed a distinct cross-sectional T2* value profile: T2* values were significantly lower in the annulus fibrosus compared with the nucleus pulposus (P = 0.01). In abnormal IVDs, T2* values were significantly lower, especially towards the centre of the disc representing the expected decreased water content of the nucleus (P = 0.01). In herniated discs, ROIs within the nucleus pulposus and ROIs covering the annulus fibrosus showed decreased T2* values. Axial T2* mapping is effective to detect early stages of degenerative disc disease. There is a potential benefit of axial T2* mapping as a diagnostic tool, allowing the quantitative assessment of intervertebral disc degeneration. circle Axial T2* mapping effective in detecting early degenerative disc disease. (orig.)

  19. Treatment of lumbar disc herniation by percutaneous laser disc decompression (PLDD) and modified PLDD

    Chi, Xiao fei; Li, Hong zhi; Wu, Ru zhou; Sui, Yun xian


    Objective: To study the micro-invasive operative method and to compare the effect of treatment of PLDD and modified PLDD for Lumbar Disc Herniation. Method: Vaporized part of the nucleus pulposus in single or multiple point after acupuncture into lumbar disc, to reach the purpose of the decompression of the lumbar disc. Result: Among the 19 cases of the regular PLDD group, the excellent and good rate was 63.2%, and among the 40 cases of the modified PLDD group, the excellent and good rate was 82.5%. Conclusion: The modified PLDD has good effect on the treatment for lumbar disc herniation.

  20. Transradicular lumbar disc herniation: An extreme variant of intraradicular disc herniation.

    Kasliwal, Manish K; Shimer, Adam L


    Intradural or intraradicular lumbar disc herniation (IDH) is a relatively rare condition often diagnosed intraoperatively. We encountered an extreme variant of IDH - a transradicular herniation as the disc material extruded through the lumbar nerve root through a split essentially transecting the nerve root. While failure to recognize intradural and intraradicular disc herniation can lead to failed back surgery, the variant described in the present case could lead to iatrogenic injury and complication if not recognized. A unique case of transradicular lumbar disc herniation in a 25-year-old patient is presented with the depiction of intraoperative images supplementing the text.

  1. CFD Analysis Of Straight Ventilated Disc Brake

    Nikhil K


    Full Text Available Brakes are the key pieces of a vehicle that plays an active role in safety and performance of the system. The study of aerodynamic cooling of a disc brake in real working condition of vehicle is important in present situations. Brake discs get very hot quickly, so it should be dissipated properly through different modes of heat transfer. Contributions of these heat transfer modes are different in different type of problems. The cooling transfer rates are different in vane surface and frictional surface of a disc brake. Also the temperature varies in each small interval of braking time. So a transient problem simulation is important to study the cooling of a disc brake when a vehicle decelerates from a particular speed. ANSYS CFX tool is used for the simulation of this transient problem.

  2. Magnetic Field Amplification via Protostellar Disc Dynamos

    Dyda, Sergei; Ustyugova, Galina V; Koldoba, Alexander V; Wasserman, Ira


    We model the generation of a magnetic field in a protostellar disc using an \\alpha-dynamo and perform axisymmetric magnetohydrodynamics (MHD) simulations of a T Tauri star. We find that for small values of the dimensionless dynamo parameter $\\alpha_d$ the poloidal field grows exponentially at a rate ${\\sigma} \\propto {\\Omega}_K \\sqrt{\\alpha_d}$ , before saturating to a value $\\propto \\sqrt{\\alpha_d}$ . The dynamo excites dipole and octupole modes, but quadrupole modes are suppressed, because of the symmetries of the seed field. Initial seed fields too weak to launch MHD outflows are found to grow sufficiently to launch winds with observationally relevant mass fluxes of order $10^{-9} M_{\\odot}/\\rm{yr}$ for T Tauri stars. For large values of $\\alpha_d$ magnetic loops are generated over the entire disc. These quickly come to dominate the disc dynamics and cause the disc to break up due to the magnetic pressure.

  3. Thermal analysis on motorcycle disc brake geometry

    W. M. Zurin W., S.; Talib, R. J.; Ismail, N. I.


    Braking is a phase of slowing and stop the movement of motorcycle. During braking, the frictional heat was generated and the energy was ideally should be faster dissipated to surrounding to prevent the built up of the excessive temperature which may lead to brake fluid vaporization, thermoelastic deformation at the contact surface, material degradation and failure. In this paper, solid and ventilated type of motorcycle disc brake are being analyse using Computational Fluid Dynamic (CFD) software. The main focus of the analysis is the thermal behaviour during braking for solid and ventilated disc brake. A comparison between both geometries is being discussed to determine the better braking performance in term of temperature distribution. It is found that ventilated disc brake is having better braking performance in terms of heat transfer compare to solid disc.

  4. Stellar Wind Erosion of Protoplanetary Discs

    Schnepf, Neesha R; Romanova, Marina


    An analytic model is developed for the erosion of protoplanetary gas discs by high velocity magnetized stellar winds. The winds are centrifugally driven from the surface of rapidly rotating, strongly magnetized young stars. The presence of the magnetic field in the wind leads to Reynolds numbers sufficiently large to cause a strongly turbulent wind/disk boundary layer which entrains and carries away the disc gas. The model uses the conservation of mass and momentum in the turbulent boundary layer. The time-scale for significant erosion depends on the disc accretion speed, accretion rate and on the wind mass loss rate. The time-scale is estimated to be ~2E6 yr. The stellar wind erosion may act in conjunction with photo-evaporation of the discs.

  5. Spiral shocks and accretion in discs

    Spruit, H.C.; Matsuda, T.; Inoue, M.; Sawada, K.


    Recent numerical and analytical results on disc-like accretion with shock waves as the only dissipation mechanism are compared. The global properties of the process are similar to those of the viscous (..cap alpha..) disc model, but precise values of the effective ..cap alpha.. value as a function of the accretion rate can be calculated. At low values of the ratio of specific heats (..gamma.. < 1.45) accretion is possible without radiative losses. Such adiabatic accretion can occur in practice at high accretion rates on to low mass objects and may be important in the formation of planets. Following previous authors, it is pointed out that non-axisymmetric perturbations in the outer parts of a disc increase in amplitude as they propagate in and cause spiral shocks more easily in a disc than perturbations originating in the inner parts.

  6. [Disc electrophoresis of collagen protein (author's transl)].

    Reitmayr, P; Verzár, F


    The composition of proteins extracted from tendon collagen is investigated by disc electrophoresis. No qualitative differences can be demonstrated between young and old collagen. The action of formaldehyde and methionine on the tendons has no effect on the electrophoretic picture.

  7. Clumps and Axisymmetric Features in Debris Discs

    Jiang, Ing-Guey


    This paper studied the structures of debris discs, focusing on the conditions that can form an axisymmetric-looking outer disc from systems with inner clumps. The main conclusion was that as long as the dominated dust grains are smaller than the blowout size, it is easy to form an axisymmetric-looking outer debris disc, which is part of a quasi-steady state of the whole system. This quasi-steady state is established through the balance between grain generations and a continuous out-going grain flow. Assuming there is an event that starts planetesimal collisions and the corresponding grain generations, this balance can be approached in a few thousand years. This result suggested that a quasi-steady-state picture could solve the possible mass budget problem of Vega's outer debris disc.

  8. Utility of polymer cerclage cables in revision shoulder arthroplasty.

    Edwards, T Bradley; Stuart, Kyle D; Trappey, George J; O'Connor, Daniel P; Sarin, Vineet K


    Revision shoulder arthroplasty often requires humeral osteotomy for stem extraction or is complicated by periprosthetic fracture. In these situations, various modes of fixation are used, including cerclage wires, cable plates, and allograft strut augmentation. The use of metal wires and cables, however, has been associated with soft tissue irritation, sharps injuries, and accelerated wear of joint arthroplasty bearing surfaces. As an alternative to traditional metal cables, the SuperCable (Kinamed Inc, Camarillo, California) contains braided ultra-high molecular-weight polyethylene fibers surrounding a nylon core. To date, no studies have examined the use of nonmetallic cerclage cables in shoulder arthroplasty.A retrospective review was performed of 11 patients who underwent shoulder arthroplasty for which nonmetallic cerclage cables were used. Clinical and radiographic data were examined regarding patient age, procedure performed, indication for cerclage cabling, time to healing of osteotomy or fracture, and any complications associated with the use of these cerclage cables. Minimum follow-up was 1 year. Ten patients underwent reverse total shoulder arthroplasty, and 1 patient underwent revision unconstrained total shoulder arthroplasty. Mean follow-up was 20.5 months. Ten patients required humeral osteotomy for stem or cement removal. Allograft augmentation was performed in 7 patients. Mean time to healing was 3.2 months. No patients experienced loosening or migration of hardware or allograft, and no complications directly related to the use of nonmetallic cerclage cables were identified. Copyright 2011, SLACK Incorporated.

  9. Massive thin accretion discs. Pt. 2; Polarization

    Laor, A.; Netzer, H. (Tel Aviv Univ. (Israel)); Piran, T. (Hebrew Univ., Jerusalem (Israel). Racah Inst. of Physics)


    Thin accretion discs around massive black holes are believed to produce much of the observed optical-UV emission from AGN. Classical calculations predict that this radiation is highly polarized at large inclination angles, in contrast to observations of quasars and Seyfert galaxies. We have calculated the spectrum and polarization of such discs using an improved radiative transfer method with all the relevant opacity sources, and a full general relativistic treatment of the radiation propagation. (author).

  10. Lyman edges in AGN accretion discs

    Czerny, B. (Copernicus Astronomical Center, Warsaw (Poland)); Pojmanski, G. (Warsaw Univ. (Poland). Obserwatorium Astronomiczne)


    We show that the basic difference in the two principal approaches to predictions of the Lyman edge in an accretion disc lies in the implicit assumption about the density of the radiating gas. Independent from the details, models predict a broad range of the edge sizes, both in absorption and in emission. Observed spectra do not exhibit any strong feature at 912 A but may still be consistent with an accretion disc mechanism if more advanced theory is developed. (author).

  11. The Annulus Property of Simple Holomorphic Discs

    Zehmisch, Kai


    We show that any simple holomorphic disc admits the annulus property, i.e., each interior point is surrounded by an arbitrary small annulus consisting entirely of injective points. As an application we show that interior singularities of holomorphic discs can be resolved after slight perturbation of the involved almost complex structure. Moreover, for boundary points the analogue notion, the half-annulus property, is introduced and studied in detail.

  12. The annulus property of simple holomorphic discs

    Zehmisch, Kai


    We show that any simple holomorphic disc admits the annulus property, i.e., each interior point is surrounded by an arbitrary small annulus consisting entirely of injective points. As an application we show that interior singularities of holomorphic discs can be resolved after slight perturbation of the almost complex structure. Moreover, for boundary points the analogue notion, the half-annulus property, is introduced and studied in detail.

  13. Three-dimensional finite element analysis of the human temporomandibular joint disc.

    Beek, M; Koolstra, J H; van Ruijven, L J; van Eijden, T M


    A three-dimensional finite element model of the articular disc of the human temporomandibular joint has been developed. The geometry of the articular cartilage and articular disc surfaces in the joint was measured using a magnetic tracking device. First, polynomial functions were fitted through the coordinates of these scattered measurements. Next, the polynomial description was transformed into a triangulated description to allow application of an automatic mesher. Finally, a finite element mesh of the articular disc was created by filling the geometry with tetrahedral elements. The articulating surfaces of the mandible and skull were modeled by quadrilateral patches. The finite element mesh and the patches were combined to create a three-dimensional model in which unrestricted sliding of the disc between the articulating surfaces was allowed. Simulation of statical joint loading at the closed jaw position predicted that the stress and strain distributions were located primarily in the intermediate zone of the articular disc with the highest values in the lateral part. Furthermore, it was predicted that considerable deformations occurred for relatively small joint loads and that relatively large variations in the direction of joint loading had little influence on the distribution of the deformations.

  14. Gene expression profile analysis of human intervertebral disc degeneration

    Kai Chen; Dajiang Wu; Xiaodong Zhu; Haijian Ni; Xianzhao Wei; Ningfang Mao; Yang Xie; Yunfei Niu; Ming Li


    In this study, we used microarray analysis to investigate the biogenesis and progression of intervertebral disc degeneration. The gene expression profiles of 37 disc tissue samples obtained from patients with herniated discs and degenerative disc disease collected by the National Cancer Institute Cooperative Tissue Network were analyzed. Differentially expressed genes between more and less degenerated discs were identified by significant analysis of microarray. A total of 555 genes were signi...

  15. Clumpy Disc and Bulge Formation

    Perez, J; Tissera, P; Michel-Dansac, L


    We present a set of hydrodynamical/Nbody controlled simulations of isolated gas rich galaxies that self-consistently include SN feedback and a detailed chemical evolution model, both tested in cosmological simulations. The initial conditions are motivated by the observed star forming galaxies at z ~ 2-3. We find that the presence of a multiphase interstellar media in our models promotes the growth of disc instability favouring the formation of clumps which in general, are not easily disrupted on timescales compared to the migration time. We show that stellar clumps migrate towards the central region and contribute to form a classical-like bulge with a Sersic index, n > 2. Our physically-motivated Supernova feedback has a mild influence on clump survival and evolution, partially limiting the mass growth of clumps as the energy released per Supernova event is increased, with the consequent flattening of the bulge profile. This regulation does not prevent the building of a classical-like bulge even for the most ...

  16. Radio Monitoring of Protoplanetary Discs

    Ubach, C.; Maddison, S. T.; Wright, C. M.; Wilner, D. J.; Lommen, D. J. P.; Koribalski, B.


    Protoplanetary disc systems observed at radio wavelengths often show excess emission above that expected from a simple extrapolation of thermal dust emission observed at short millimetre wavelengths. Monitoring the emission at radio wavelengths can be used to help disentangle the physical mechanisms responsible for this excess, including free-free emission from a wind or jet, and chromospheric emission associated with stellar activity. We present new results from a radio monitoring survey conducted with Australia Telescope Compact Array over the course of several years with observation intervals spanning days, months and years, where the flux variability of 11 T Tauri stars in the Chamaeleon and Lupus star forming regions was measured at 7 and 15 mm and 3 and 6 cm. Results show that for most sources are variable to some degree at 7 mm, indicating the presence of emission mechanisms other than thermal dust in some sources. Additionally, evidence of grain growth to cm-sized pebbles was found for some sources that also have signs of variable flux at 7 mm. We conclude that multiple processes contributing to the emission are common in T Tauri stars at 7 mm and beyond, and that a detection at a single epoch at radio wavelengths should not be used to determine all processes contributing to the emission.

  17. The maximum rotation of a galactic disc

    Bottema, R


    The observed stellar velocity dispersions of galactic discs show that the maximum rotation of a disc is on average 63% of the observed maximum rotation. This criterion can, however, not be applied to small or low surface brightness (LSB) galaxies because such systems show, in general, a continuously rising rotation curve until the outermost measured radial position. That is why a general relation has been derived, giving the maximum rotation for a disc depending on the luminosity, surface brightness, and colour of the disc. As a physical basis of this relation serves an adopted fixed mass-to-light ratio as a function of colour. That functionality is consistent with results from population synthesis models and its absolute value is determined from the observed stellar velocity dispersions. The derived maximum disc rotation is compared with a number of observed maximum rotations, clearly demonstrating the need for appreciable amounts of dark matter in the disc region and even more so for LSB galaxies. Matters h...

  18. Magnetic white dwarfs with debris discs

    Külebi, Baybars; Lorén-Aguilar, Pablo; Isern, Jordi; García-Berro, Enrique


    It has long been accepted that a possible mechanism for explaining the existence of magnetic white dwarfs is the merger of a binary white dwarf system, as there are viable mechanisms for producing sustainable magnetic fields within the merger product. However, the lack of rapid rotators in the magnetic white dwarf population has been always considered a problematic issue of this scenario. Smoothed Particle Hydrodynamics simulations show that in mergers in which the two white dwarfs have different masses a disc around the central compact object is formed. If the central object is magnetized it can interact with the disc through its magnetosphere. The torque applied by the disc changes the spin of the star, whereas the transferred angular momentum from the star to the disc determines the properties of the disc. In this work we build a model for the disc evolution under the effect of magnetic accretion, and for the angular momentum evolution of the star, which can be compared with the observations. Our model pre...

  19. Turbulent drag reduction through oscillating discs

    Wise, Daniel J


    The changes of a turbulent channel flow subjected to oscillations of wall flush-mounted rigid discs are studied by means of direct numerical simulations. The Reynolds number is $R_\\tau$=$180$, based on the friction velocity of the stationary-wall case and the half channel height. The primary effect of the wall forcing is the sustained reduction of wall-shear stress, which reaches a maximum of 20%. A parametric study on the disc diameter, maximum tip velocity, and oscillation period is presented, with the aim to identify the optimal parameters which guarantee maximum drag reduction and maximum net energy saving, computed by taking into account the power spent to actuate the discs. This may be positive and reaches 6%. The Rosenblat viscous pump flow is used to predict the power spent for disc motion in the turbulent channel flow and to estimate localized and transient regions over the disc surface subjected to the turbulent regenerative braking effect, for which the wall turbulence exerts work on the discs. The...

  20. The Diversity of Thick Galactic Discs

    Kasparova, Anastasia V; Chilingarian, Igor V; Silchenko, Olga K; Moiseev, Alexey V; Borisov, Svyatoslav B


    Although thick stellar discs are detected in nearly all edge-on disc galaxies, their formation scenarios still remain a matter of debate. Due to observational difficulties, there is a lack of information about their stellar populations. Using the Russian 6-m telescope BTA we collected deep spectra of thick discs in three edge-on S0-a disc galaxies located in different environments: NGC4111 in a dense group, NGC4710 in the Virgo cluster, and NGC5422 in a sparse group. We see intermediate age (4-5 Gyr) metal rich ([Fe/H] $\\sim$ -0.2 - 0.0 dex) stellar populations in NGC4111 and NGC4710. On the other hand, NGC5422 does not harbour young stars, its disc is thick and old (10 Gyr), without evidence for a second component, and its $\\alpha$-element abundance suggests a 1.5-2 Gyr long formation epoch implying its formation at high redshift. Our results suggest the diversity of thick disc formation scenarios.

  1. The role of disc self-gravity in circumbinary planet systems - I. Disc structure and evolution

    Mutter, Matthew M.; Pierens, Arnaud; Nelson, Richard P.


    We present the results of two-dimensional hydrodynamic simulations of self-gravitating circumbinary discs around binaries whose parameters match those of the circumbinary planet-hosting systems Kepler-16, Kepler-34 and Kepler-35. Previous work has shown that non-self-gravitating discs in these systems form an eccentric precessing inner cavity due to tidal truncation by the binary, and planets which form at large radii migrate until stalling at this cavity. Whilst this scenario appears to provide a natural explanation for the observed orbital locations of the circumbinary planets, previous simulations have failed to match the observed planet orbital parameters. The aim of this work is to examine the role of self-gravity in modifying circumbinary disc structure as a function of disc mass, prior to considering the evolution of embedded circumbinary planets. In agreement with previous work, we find that for disc masses between one and five times the minimum mass solar nebula (MMSN), disc self-gravity affects modest changes in the structure and evolution of circumbinary discs. Increasing the disc mass to 10 or 20 MMSN leads to two dramatic changes in disc structure. First, the scale of the inner cavity shrinks substantially, bringing its outer edge closer to the binary. Secondly, in addition to the eccentric inner cavity, additional precessing eccentric ring-like features develop in the outer regions of the discs. If planet formation starts early in the disc lifetime, these changes will have a significant impact on the formation and evolution of planets and precursor material.

  2. Fatal cobalt toxicity after total hip arthroplasty revision for fractured ceramic components.

    Fox, Kimberly A; Phillips, Todd M; Yanta, Joseph H; Abesamis, Michael G


    obtained two days before she expired was 641.6 mcg/L. This is a case of fatal cobalt-induced cardiomyopathy in a patient whose ceramic components of a total hip arthroplasty fractured causing metallosis with worsening cobalt toxicity. We recommend that when a fractured device is revised with a prosthesis with cobalt-chromium components, whole blood and urine cobalt measurements should be obtained and periodically monitored to evaluate for rising concentrations. Providers should be aware of clinical signs and symptoms of cobalt toxicity in patients who have prostheses with cobalt-chromium components. If suspected, toxicology and orthopedics should be involved for possible chelation and removal of the prosthesis.

  3. Prevalence of adjacent segment disc degeneration in patients undergoing anterior cervical discectomy and fusion based on pre-operative MRI findings.

    Lundine, Kristopher M; Davis, Gavin; Rogers, Myron; Staples, Margaret; Quan, Gerald


    Anterior cervical discectomy and fusion (ACDF) is a widely accepted surgical treatment for symptomatic cervical spondylosis. Some patients develop symptomatic adjacent segment degeneration, occasionally requiring further treatment. The cause and prevalence of adjacent segment degeneration and disease is unclear at present. Proponents for motion preserving surgery such as disc arthroplasty argue that this technique may decrease the "strain" on adjacent discs and thus decrease the incidence of symptomatic adjacent segment degeneration. The purpose of this study was to assess the pre-operative prevalence of adjacent segment degeneration in patients undergoing ACDF. A database review of three surgeons' practice was carried out to identify patients who had undergone a one- or two-level ACDF for degenerative disc disease. Patients were excluded if they were operated on for recent trauma, had an inflammatory arthropathy (for example, rheumatoid arthritis), or had previous spine surgery. The pre-operative MRI of each patient was reviewed and graded using a standardised methodology. One hundred and six patient MRI studies were reviewed. All patients showed some evidence of intervertebral disc degeneration adjacent to the planned operative segment(s). Increased severity of disc degeneration was associated with increased age and operative level, but was not associated with sagittal alignment. Disc degeneration was more common at levels adjacent to the surgical level than at non-adjacent segments, and was more severe at the superior adjacent level compared with the inferior adjacent level. These findings support the theory that adjacent segment degeneration following ACDF is due in part to the natural history of cervical spondylosis.

  4. Outcomes of Varus Valgus Constrained Versus Rotating-Hinge Implants in Total Knee Arthroplasty.

    Malcolm, Tennison L; Bederman, S Samuel; Schwarzkopf, Ran


    The stability of a total knee arthroplasty is determined by the ability of the prosthesis components in concert with supportive bone and soft tissue structures to sufficiently resist deforming forces transmitted across the knee joint. Constrained prostheses are used in unstable knees due to their ability to resist varus and valgus transformative forces across the knee. Constraint requires inherent rigidity, which can facilitate early implant failure. The purpose of this study was to describe the comparative indications for surgery and postoperative outcomes of varus valgus constrained knee (VVK) and rotating-hinge knee (RHK) total knee arthroplasty prostheses. Seven retrospective observational studies describing 544 VVK and 254 RHK patients with an average follow-up of 66 months (range, 7-197 months) were evaluated. Patients in both groups experienced similar failure rates (P=.74), ranges of motion (P=.81), and Knee Society function scores (P=.29). Average Knee Society knee scores were 4.2 points higher in VVK patients compared with RHK patients, indicating minimal mid-term clinical differences may exist (P<.0001). Absent collateral ligament support is an almost universal indication for RHK implantation vs VVK. Constrained device implantation is routinely guided by inherent stability of the knee, and, when performed, similar postoperative outcomes can be achieved with VVK and RHK prostheses.

  5. Isolated patellofemoral arthroplasty reproduces natural patellofemoral joint kinematics when the patella is resurfaced.

    Vandenneucker, Hilde; Labey, Luc; Vander Sloten, Jos; Desloovere, Kaat; Bellemans, Johan


    The objectives of this in vitro project were to compare the dynamic three-dimensional patellofemoral kinematics, contact forces, contact areas and contact pressures of a contemporary patellofemoral prosthetic implant with those of the native knee and to measure the influence of patellar resurfacing and patellar thickness. The hypothesis was that these designs are capable to reproduce the natural kinematics but result in higher contact pressures. Six fresh-frozen specimens were tested on a custom-made mechanical knee rig before and after prosthetic trochlear resurfacing, without and with patellar resurfacing in three different patellar thicknesses. Full three-dimensional kinematics were analysed during three different motor tasks, using infrared motion capture cameras and retroflective markers. Patellar contact characteristics were registered using a pressure measuring device. The patellofemoral kinematic behaviour of the patellofemoral arthroplasty was similar to that of the normal knee when the patella was resurfaced, showing only significant (p patella was resurfaced. From a kinematic point of view, patellar resurfacing may be advisable. However, the substantially elevated patellar contact pressures remain a point of concern in the decision whether or not to resurface the patella. This study therefore not only adds a new point in the discussion whether or not to resurface the patella, but also supports the claimed advantage that a patellofemoral arthroplasty is capable to reproduce the natural knee kinematics.

  6. Changes in bone mineral density of the acetabulum and proximal femur after total hip resurfacing arthroplasty.

    Huang, Qiang; Shen, Bin; Yang, Jing; Zhou, Zong-ke; Kang, Peng-de; Pei, Fu-xing


    Our aim was to investigate the changes in bone mineral density (BMD) of acetabulum and proximal femur after total hip resurfacing arthroplasty. A comparative study was carried out on 51 hips in 48 patients. Group A consisted of 25 patients (26 hips) who had undergone total hip resurfacing and group B consisted of 23 patients (25 hips) who had had large-diameter metal-on-metal total hip arthroplasty (THA). BMDs around the acetabulum and proximal femur were measured using dual-energy x-ray absorptiometry (DEXA) at 2 weeks, 6 months, 1 year and annually thereafter during the 3 years after surgery. At final follow-up, the acetabular net mean BMD decreased by 11% in group A and 10% in group B with no differences between two groups (P = .35). For the femoral side, in Gruen zone 1, the mean BMD increased by 4% in group A, whereas it decreased by 11% in group B (P = .029). In Gruen zone 7, the mean BMD increased by 8% at the final follow-up in group A, whereas it decreased by 13% in group B (P = .02). In both groups the mean BMD increased by 3% in Gruen zones 3, 4, 5, and 6. Stress-related bone loss of the acetabulum was comparable for MOM THA and resurfacing devices, but proximal femoral bone density increased in the resurfacing group and decreased in the THA group.

  7. Endotoxins in surgical instruments of hip arthroplasty

    Vania Regina Goveia


    Full Text Available Abstract OBJECTIVE To investigate endotoxins in sterilized surgical instruments used in hip arthroplasties. METHOD A descriptive exploratory study conducted in a public teaching hospital. Six types of surgical instruments were selected, namely: acetabulum rasp, femoral rasp, femoral head remover, chisel box, flexible bone reamer and femoral head test. The selection was based on the analysis of the difficulty in removing bone and blood residues during cleaning. The sample was made up of 60 surgical instruments, which were tested for endotoxins in three different stages. The EndosafeTM Gel-Clot LAL (Limulus Amebocyte Lysate method was used. RESULT There was consistent gel formation with positive analysis in eight instruments, corresponding to 13.3%, being four femoral rasps and four bone reamers. CONCLUSION Endotoxins in quantity ≥0.125 UE/mL were detected in 13.3% of the instruments tested.

  8. Noise measurement in total knee arthroplasty

    Lukas A Holzer


    Full Text Available Few studies have been performed to analyze noise levels produced by various surgical instruments in the operating room (OR. The highest levels of noise that have been described were due to instruments used for total knee arthroplasty (TKA. These high levels of noise might be a potential health hazard for patients and medical staff. Therefore, we aimed to measure noise levels of current instruments that are widely used worldwide. During a conventional primary TKA the levels of noise in the OR were measured using a Class 1 integrating-averaging sound level meter. The highest A-weighted equivalent level was produced when using a hammer during the implantation of the femoral and tibial components with 90.2 dBA. In total surgical instruments were used for about 10% of the total time of surgery. Noise exposure due to instrument use during TKA does not seem to be a potential health hazard for medical staff or patients.

  9. Total hip arthroplasty in heart transplant patients.

    León, José Luis; Resines, Carlos; Zafra, Alberto


    Avascular necrosis of the femoral head (AVNFH) is a known complication after heart transplantation. In order to assess the efficacy and complications of cementless total hip arthroplasty (THA) in this population, the authors analysed 24 cementless THAs in 18 patients with advanced AVNFH (stage II affecting more than 15% of the articular surface, stage III and IV according to the Ficat-Arlet classification) after a heart transplant procedure. Average duration of follow-up was 35.4 months (range: 16 to 66). Pain and function scores (Harris Hip Score and WOMAC arthritis index) showed significant improvement from the preoperative levels. There was no evidence of component loosening, heart-related complications or infection following the THA. Cementless THA is a reasonable treatment option for advanced avascular necrosis of the femoral head following heart transplant procedures.

  10. Revision of infected knee arthroplasties in Denmark

    Lindberg-Larsen, Martin; Jørgensen, Christoffer C; Bagger, Jens;


    Background and purpose - The surgical treatment of periprosthetic knee infection is generally either a partial revision procedure (open debridement and exchange of the tibial insert) or a 2-stage exchange arthroplasty procedure. We describe the failure rates of these procedures on a nationwide...... prosthesis with a re-revision rate due to infection of 34%, as compared to 55% in revisions of a revision prosthesis (p = 0.05). The failure rate of the 2-stage revisions was 30%. Median time interval between stages was 84 (9-597) days. 117 (54%) of the 2-stage revisions were revisions of a primary...... prosthesis with a re-revision rate due to infection of 21%, as compared to 29% in revisions of a previously revised prosthesis (p = 0.1). Overall postoperative mortality was 0.6% in high-volume centers (> 30 procedures within 2 years) as opposed to 7% in the remaining centers (p = 0.003). Interpretation...

  11. Fracture Blisters After Primary Total Knee Arthroplasty.

    Halawi, Mohamad J


    Fracture blisters are tense vesicles that arise on markedly swollen skin overlying traumatized soft tissue. While this relatively uncommon complication has been well described in the trauma literature, this article reports for the first time a case of fracture blisters after primary total knee arthroplasty. The fracture blisters developed within 36 hours of surgery and were associated with profound swelling and erythema. There was no evidence of vascular injury, compartment syndrome, iatrogenic fracture, or deep venous thrombosis. The patient was treated with leg elevation, loosely applied nonadhesive dressings, and a short course of oral antibiotics after skin desquamation. Blood-filled blisters required longer time to reepithelialization than fluid-filled blisters. Knee stiffness developed because of pain and fear of participation with physical therapy, but the patient was able to resume intensive rehabilitation after resolution of the blisters. Patient factors, surgical factors, and review of the literature are discussed.

  12. Extensor mechanism disruption after total knee arthroplasty.

    Bates, Michael D; Springer, Bryan D


    Extensor mechanism disruption is a rare and potentially devastating complication associated with total knee arthroplasty. Disruption can occur at the quadriceps or patellar tendons or, in the setting of a fracture, at the patella. Recognition of the risk factors for disruption and prevention via meticulous surgical technique are critical to avoid this complication. Various management techniques and the challenges associated with treatment have been described. Nonsurgical management consists of the use of walking aids and/or knee braces, which may not be acceptable for the active patient. Surgical options include primary repair and reconstructive techniques using allograft, autograft, synthetic material, and gastrocnemius rotational flaps. However, no single method has reliably demonstrated satisfactory outcomes. Although research on reconstructive procedures with synthetic materials has been promising, further study is need to assess the use of these materials.

  13. Favorable results after total wrist arthroplasty

    Boeckstyns, Michel E. H.; Herzberg, G.; Merser, Søren


    Background and purpose During the past 40 years, several attempts have been made with total wrist arthroplasty to avoid fusion in severely destroyed wrists. The results have often been disappointing. There is only modest clinical documentation due to the small number of patients (especially non....... The wrists had been reviewed annually and analysis was done on the latest follow-up data. Results 60 patients had been operated (5 bilaterally), 5 wrists had been revised, and 52 were available for follow-up (with the revised cases excluded). The pain scores, QuickDASH scores, ulnar flexion, and supination...... for the whole group were statistically significantly better at follow-up. There were no statistically significant differences between the rheumatoid and the non-rheumatoid patients except for motion, which was better in the non-rheumatoid group. The motion obtained depended on the preoperative motion. Implant...


    N. N. Kornilov


    Full Text Available In the article recent publications dedicated to unicompartmental knee arthroplasty are analyzed. Evolution of indications and contraindications, mid- and late term results, difference in functional outcomes in comparison with total knee arthroplasty are discussed. Taking into consideration all relevant information unicompartmental knee arthroplasty may be considered as effective and reliable method of treatment of patients with knee osteoarthrosis and osteonecrosis.

  15. Drain tip culture following total knee arthroplasty

    Bahubali Aski


    Full Text Available Background: Placing a suction drain following total knee replacement is usual practice which is been followed by many surgeons. Closed suction drainage following arthroplasty is a routine with the aim of preventing wound hematoma and thereby reducing the risk of infection. Surgical site infections in orthopaedic surgeries are disastrous and often lead to significant morbidity and mortality. Usefulness of drain tip culture in predicting the wound infection is been tested but results are controversial. Methods: It is a prospective study of 546 drains (352 patients who underwent unilateral or bilateral Total Knee Arthroplasty (TKA. The drain tip was sent for culture at the time of removing. Cultures from the SSI (surgical site infection were also collected. Cases that had at least six months of follow up were included in the study. However in one patient with superficial infection, the drain tip culture was negative. Results: Drain tip culture was positive in total of 18 patients. Three patients had developed deep infection and 10 patients had superficial infection. All three patients with deep infection and 9 out of 10 patients of superficial infection were culture positive. Out of 8 culture positive superficial infections, one had different bacteria identified from the site. Drain tip culture was positive in 3.39% of drains and infection rate was positive in 1.88% of wounds. On statistical analysis we found drain tip culture sensitivity of 90%, specificity of 98.46%, positive predictive value of 52.9% and negative predictive value of 99.8%. Conclusion: Drain tip culture positivity helps in predicting the future chance of developing the infection. If drain tip culture is negative, then there is almost near nil chances of infection. [Int J Res Med Sci 2015; 3(2.000: 409-411

  16. Minimally invasive total hip arthroplasty: in opposition.

    Hungerford, David S


    At the Knee Society Winter Meeting in 2003, Seth Greenwald and I debated about whether there should be new standards (ie, regulations) applied to the release of information to the public on "new developments." I argued for the public's "right to know" prior to the publication of peer-reviewed literature. He argued for regulatory constraint or "proving by peer-reviewed publication" before alerting the public. It is not a contradiction for me to currently argue against the public advertising of minimally invasive (MIS) total hip arthroplasty as not yet being in the best interest of the public. It is hard to remember a concept that has so captured both the public's and the surgical community's fancy as MIS. Patients are "demanding" MIS without knowing why. Surgeons are offering it as the next best, greatest thing without having developed the skill and experience to avoid the surgery's risks. If you put "minimally invasive hip replacement" into the Google search engine (, you get 5,170 matches. If you put the same words in PubMed (, referencing the National Library of Medicine database, you get SEVENTEEN; none is really a peer-reviewed article. Most are 1 page papers in orthopedics from medical education meetings. On the other hand, there are over 6,000 peer-reviewed articles on total hip arthroplasty. Dr. Thomas Sculco, my couterpart in this debate, wrote an insightful editorial in the American Journal of Orthopedic Surgery in which he stated: "Although these procedures have generated incredible interest and enthusiasm, I am concerned that they may be performed to the detriment of our patients." I couldn't agree with him more. Smaller is not necessarily better and, when it is worse, it will be the "smaller" that is held accountable.

  17. Evolution from protoplanetary to debris discs: The transition disc around HD 166191

    Kennedy, G M; Lisse, C M; Ménard, F; Sitko, M L; Wyatt, M C; Bayliss, D D R; DeMeo, F E; Crawford, K B; Kim, D L; Rudy, R J; Russell, R W; Sibthorpe, B; Skinner, M A; Zhou, G


    HD 166191 has been identified by several studies as hosting a rare and extremely bright warm debris disc with an additional outer cool disc component. However, an alternative interpretation is that the star hosts a disc that is currently in transition between a full gas disc and a largely gas-free debris disc. With the help of new optical to mid-IR spectra and Herschel imaging, we argue that the latter interpretation is supported in several ways: i) we show that HD 166191 is co-moving with the ~4 Myr-old Herbig Ae star HD 163296, suggesting that the two have the same age, ii) the disc spectrum of HD 166191 is well matched by a standard radiative transfer model of a gaseous protoplanetary disc with an inner hole, and iii) the HD 166191 mid-IR silicate feature is more consistent with similarly primordial objects. We note some potential issues with the debris disc interpretation that should be considered for such extreme objects, whose lifetime at the current brightness is mush shorter than the stellar age, or i...

  18. A Simulation Model of Focus and Radial Servos in Compact Disc Players with Disc Surface Defects

    Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle;


    Compact Disc players have been on the market in more than two decades.As a consequence most of the control servo problems have been solved. A large remaining problem to solve is the handling of Compact Discs with severe surface defects like scratches and fingerprints. This paper introduces a method...

  19. Hybrid Surgery Versus Anterior Cervical Discectomy and Fusion in Multilevel Cervical Disc Diseases: A Meta-Analysis.

    Zhang, Jianfeng; Meng, Fanxin; Ding, Yan; Li, Jie; Han, Jian; Zhang, Xintao; Dong, Wei


    To investigate the outcomes and reliability of hybrid surgery (HS) versus anterior cervical discectomy and fusion (ACDF) for the treatment of multilevel cervical spondylosis and disc diseases.Hybrid surgery, combining cervical disc arthroplasty (CDA) with fusion, is a novel treatment to multilevel cervical degenerated disc disease in recent years. However, the effect and reliability of HS are still unclear compared with ACDF.To investigate the studies of HS versus ACDF in patients with multilevel cervical disease, electronic databases (Medline, Embase, Pubmed, Cochrane library, and Cochrane Central Register of Controlled Trials) were searched. Studies were included when they compared HS with ACDF and reported at least one of the following outcomes: functionality, neck pain, arm pain, cervical range of motion (ROM), quality of life, and incidence of complications. No language restrictions were used. Two authors independently assessed the methodological quality of included studies and extracted the relevant data.Seven clinical controlled trials were included in this study. Two trials were prospective and the other 5 were retrospective. The results of the meta-analysis indicated that HS achieved better recovery of NDI score (P = 0.038) and similar recovery of VAS score (P = 0.058) compared with ACDF at 2 years follow-up. Moreover, the total cervical ROM (C2-C7) after HS was preserved significantly more than the cervical ROM after ACDF (P = 0.000) at 2 years follow-up. Notably, the compensatory increase of the ROM of superior and inferior adjacent segments was significant in ACDF groups at 2-year follow-up (P multilevel cervical spondylosis to preserve cervical ROM and reduce the risk of adjacent disc degeneration. Nonetheless, more well-designed studies with large groups of patients are required to provide further evidence for the benefit and reliability of HS for the treatment of cervical disk diseases.

  20. Stem cell horizons in intervertebral disc degeneration

    Joseph Ciacci


    Full Text Available Joseph Ciacci1, Allen Ho1,2, Christopher P Ames3, Rahul Jandial41Division of Neurosurgery, University of California, San Diego, La Jolla, California, USA; 2Del E Webb Neurosciences, Aging and Stem Cell Research Center, The Burnham Institute for Medical Research, La Jolla, California, USA; 3Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, USA; 4Division of Neurosurgery, Department of Surgery, City of Hope Cancer Center, Duarte, CA, USAAbstract: Intervertebral disc degeneration remains a pervasive and intractable disease arising from a combination of aging and stress on the back and spine. The growing field of regenerative medicine brings the promise of stem cells in the treatment of disc disease. Scientists and physicians hope to employ stem cells not only to stop, but also reverse degeneration. However, there are many important outstanding issues, including the hostile avascular, apoptotic physiological environment of the intervertebral disc, and the difficulty of obtaining mesenchymal stem cells, and directing them towards chondrocytic differentiation and integration within the nucleus pulposus of the disc. Given the recent advances in minimally invasive spine surgery, and developing body of work on stem cell manipulation and transplantation, stem cells are uniquely poised to bring about large-scale improvements in treatment and outcomes for degenerative disc disease. In this review we will first discuss the cellular and molecular factors influencing degeneration, and then examine the efficacy and difficulties of stem cell transplantation.Keywords: intervertebral disc degeneration, stem cells, disc disease, mesenchymal stem cells, stem cell transplantation

  1. Cervical disc hernia operations through posterior laminoforaminotomy

    Coskun Yolas


    Full Text Available Objective: The most common used technique for posterolateral cervical disc herniations is anterior approach. However, posterior cervical laminotoforaminomy can provide excellent results in appropriately selected patients with foraminal stenosis in either soft disc prolapse or cervical spondylosis. The purpose of this study was to present the clinical outcomes following posterior laminoforaminotomy in patients with radiculopathy. Materials and Methods: We retrospectively evaluated 35 patients diagnosed with posterolateral cervical disc herniation and cervical spondylosis with foraminal stenosis causing radiculopathy operated by the posterior cervical keyhole laminoforaminotomy between the years 2010 and 2015. Results: The file records and the radiographic images of the 35 patients were assessed retrospectively. The mean age was 46.4 years (range: 34-66 years. Of the patients, 19 were males and 16 were females. In all of the patients, the neurologic deficit observed was radiculopathy. The posterolaterally localized disc herniations and the osteophytic structures were on the left side in 18 cases and on the right in 17 cases. In 10 of the patients, the disc level was at C5-6, in 18 at C6-7, in 2 at C3-4, in 2 at C4-5, in 1 at C7-T1, in 1 patient at both C5-6 and C6-7, and in 1 at both C4-5 and C5-6. In 14 of these 35 patients, both osteophytic structures and protruded disc herniation were present. Intervertebral foramen stenosis was present in all of the patients with osteophytes. Postoperatively, in 31 patients the complaints were relieved completely and four patients had complaints of neck pain and paresthesia radiating to the arm (the success of operation was 88.5%. On control examinations, there was no finding of instability or cervical kyphosis. Conclusion: Posterior cervical laminoforaminotomy is an alternative appropriate choice in both cervical soft disc herniations and cervical stenosis.

  2. Reconstructing the star formation history of the Milky Way disc(s) from chemical abundances

    Snaith, O.; Haywood, M.; Di Matteo, P.; Lehnert, M. D.; Combes, F.; Katz, D.; Gómez, A.


    We develop a chemical evolution model to study the star formation history of the Milky Way. Our model assumes that the Milky Way has formed from a closed-box-like system in the inner regions, while the outer parts of the disc have experienced some accretion. Unlike the usual procedure, we do not fix the star formation prescription (e.g. Kennicutt law) to reproduce the chemical abundance trends. Instead, we fit the abundance trends with age to recover the star formation history of the Galaxy. Our method enables us to recover the star formation history of the Milky Way in the first Gyrs with unprecedented accuracy in the inner (R 9-10 kpc) discs, as sampled in the solar vicinity. We show that half the stellar mass formed during the thick-disc phase in the inner galaxy during the first 4-5 Gyr. This phase was followed by a significant dip in star formation activity (at 8-9 Gyr) and a period of roughly constant lower-level star formation for the remaining 8 Gyr. The thick-disc phase has produced as many metals in 4 Gyr as the thin-disc phase in the remaining 8 Gyr. Our results suggest that a closed-box model is able to fit all the available constraints in the inner disc. A closed-box system is qualitatively equivalent to a regime where the accretion rate maintains a high gas fraction in the inner disc at high redshift. In these conditions the SFR is mainly governed by the high turbulence of the interstellar medium. By z ~ 1 it is possible that most of the accretion takes place in the outer disc, while the star formation activity in the inner disc is mostly sustained by the gas that is not consumed during the thick-disc phase and the continuous ejecta from earlier generations of stars. The outer disc follows a star formation history very similar to that of the inner disc, although initiated at z ~ 2, about 2 Gyr before the onset of the thin-disc formation in the inner disc.

  3. Meralgia paresthetica-like symptoms following epidural analgesia after total knee arthroplasty.

    Shin, H J; Kim, Y H; Lee, H W


    Meralgia paresthetica (MP) is generally caused by entrapment of the lateral femoral cutaneous nerve (LFCN), and presents with pain and paresthesia in the anterolateral thigh. This paper describes a patient who had MP-like symptoms as a result of continuous epidural analgesia after total knee arthroplasty. The patient with pre-existing left foraminal stenosis at L3-L4 and disc herniations at L4-5 did not complain of paresthesia or pain during the combined spinal-epidural anesthetic procedure. However, during epidural analgesia on the second post-operative day, he complained of paresthesia and pain in the anterolateral thigh of the contralateral leg. Electromyography showed a neurogenic lesion at the level of L3. Although an ultrasound-guided diagnostic block of the LFCN was performed twice post-operatively, the patient's symptoms persisted. The symptoms gradually resolved 12 months after the surgery. In our case, we suggest that the continuous epidural infusate caused neural ischemia of the L3 nerve root by a compressive effect. © 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  4. Conversion paralysis after cervical spine arthroplasty: a case report and literature review.

    Boudissa, M; Castelain, J E; Boissière, L; Mariey, R; Pointillart, V; Vital, J M


    We report a case of conversion paralysis after cervical spine arthroplasty performed in a 45-year-old woman to treat cervico-brachial neuralgia due to a left-sided C6-C7 disc herniation. Upon awakening from the anaesthesia, she had left hemiplegia sparing the face, with normal sensory function. Magnetic resonance imaging (MRI) of the brain ruled out a stroke. MRI of the spinal cord showed artefacts from the cobalt-chrome prosthesis that precluded confident elimination of mechanical spinal cord compression. Surgery performed on the same day to substitute a cage for the prosthesis ruled out spinal cord compression, while eliminating the source of MRI artefacts. Findings were normal from follow-up MRI scans 1 and 15days later, as well as from neurophysiological testing (electromyogram and motor evoked potentials). The deficit resolved fully within the next 4days. A psychological assessment revealed emotional distress related to an ongoing divorce. The most likely diagnosis was conversion paralysis. Surgeons should be aware that conversion disorder might develop after a procedure on the spine, although the risk of litigation requires re-operation. Familiarity with specific MRI sequences that minimise artefacts can be valuable. A preoperative psychological assessment might improve the detection of patients at high risk for conversion disorder.

  5. Revision of Failed Hip Resurfacing and Large Metal-on-Metal Total Hip Arthroplasty Using Dual-Mobility Components.

    Snir, Nimrod; Park, Brian K; Garofolo, Garret; Marwin, Scott E


    Revision of metal-on-metal (MoM) total hip arthroplasty (THA) or hip resurfacing is associated with high complication rates. The authors propose dual-mobility components as a surgical option and present short- to mid-term results of MoM hips revised with dual-mobility components. Eighteen consecutive hips that underwent revision of MoM THA or hip resurfacing using dual-mobility components were identified. At final follow-up (mean, 17.5 months), the visual analog scale, modified Harris Hip Score, and SF-12 scores had all improved (Phip resurfacing using a dual-mobility device is an effective strategy.

  6. In vitro-analysis of kinematics and intradiscal pressures in cervical arthroplasty versus fusion--A biomechanical study in a sheep model with two semi-constrained prosthesis.

    Daentzer, Dorothea; Welke, Bastian; Hurschler, Christof; Husmann, Nathalie; Jansen, Christina; Flamme, Christian Heinrich; Richter, Berna Ida


    As an alternative technique to arthrodesis of the cervical spine, total disc replacement (TDR) has increasingly been used with the aim of restoration of the physiological function of the treated and adjacent motions segments. The purpose of this experimental study was to analyze the kinematics of the target level as well as of the adjacent segments, and to measure the pressures in the proximal and distal disc after arthrodesis as well as after arthroplasty with two different semi-constrained types of prosthesis. Twelve cadaveric ovine cervical spines underwent polysegmental (C2-5) multidirectional flexibility testing with a sensor-guided industrial serial robot. Additionally, pressures were recorded in the proximal and distal disc. The following three conditions were tested: (1) intact specimen, (2) single-level arthrodesis C3/4, (3) single-level TDR C3/4 using the Discover® in the first six specimens and the activ® C in the other six cadavers. Statistical analysis was performed for the total range of motion (ROM), the intervertebral ROM (iROM) and the intradiscal pressures (IDP) to compare both the three different conditions as well as the two disc prosthesis among each other. The relative iROM in the target level was always lowered after fusion in the three directions of motion. In almost all cases, the relative iROM of the adjacent segments was almost always higher compared to the physiologic condition. After arthroplasty, we found increased relative iROM in the treated level in comparison to intact state in almost all cases, with relative iROM in the adjacent segments observed to be lower in almost all situations. The IDP in both adjacent discs always increased in flexion and extension after arthrodesis. In all but five cases, the IDP in each of the adjacent level was decreased below the values of the intact specimens after TDR. Overall, in none of the analyzed parameters were statistically significantly differences between both types of prostheses

  7. Dynamical instabilities in disc-planet interactions

    Lin, Min-Kai


    Protoplanetary discs may become dynamically unstable due to structure induced by an embedded giant planet. In this thesis, I discuss the stability of such systems and explore the consequence of instability on planetary migration. I begin with non-self-gravitating, low viscosity discs and show that giant planets induce shocks inside its co-orbital region, leading to a profile unstable to vortex formation around a potential vorticity minimum. This instability is commonly known as the vortex or Rossby wave instability. Vortex-planet interaction lead to episodic phases of migration, which can be understood in the framework of type III migration. I then examine the effect of disc self-gravity on gap stability. The linear theory of the Rossby wave instability is extended to include disc gravity, which shows that self-gravity is effective at stabilising the vortex instability at small azimuthal wavenumber. This is consistent with the observation that more vortices develop with increasing disc mass in hydrodynamic si...

  8. Debris Discs: Modeling/theory review

    Thébault, P.


    An impressive amount of photometric, spectroscopic and imaging observations of circumstellar debris discs has been accumulated over the past 3 decades, revealing that they come in all shapes and flavours, from young post-planet-formation systems like Beta-Pic to much older ones like Vega. What we see in these systems are small grains, which are probably only the tip of the iceberg of a vast population of larger (undetectable) collisionally-eroding bodies, leftover from the planet-formation process. Understanding the spatial structure, physical properties, origin and evolution of this dust is of crucial importance, as it is our only window into what is going on in these systems. Dust can be used as a tracer of the distribution of their collisional progenitors and of possible hidden massive pertubers, but can also allow to derive valuable information about the disc's total mass, size distribution or chemical composition. I will review the state of the art in numerical models of debris disc, and present some important issues that are explored by current modelling efforts: planet-disc interactions, link between cold (i.e. Herschel-observed) and hot discs, effect of binarity, transient versus continuous processes, etc. I will finally present some possible perspectives for the development of future models.

  9. The inner cavity of the circumnuclear disc

    Blank, Marvin; Frank, Adam; Carroll-Nellenback, Jonathan J; Duschl, Wolfgang J


    The circumnuclear disc (CND) orbiting the Galaxy's central black hole is a reservoir of material that can ultimately provide energy through accretion, or form stars in the presence of the black hole, as evidenced by the stellar cluster that is presently located at the CND's centre. In this paper, we report the results of a computational study of the dynamics of the CND. The results lead us to question two paradigms that are prevalent in previous research on the Galactic Centre. The first is that the disc's inner cavity is maintained by the interaction of the central stellar cluster's strong winds with the disc's inner rim, and second, that the presence of unstable clumps in the disc implies that the CND is a transient feature. Our simulations show that, in the absence of a magnetic field, the interaction of the wind with the inner disc rim actually leads to a filling of the inner cavity within a few orbital time-scales, contrary to previous expectations. However, including the effects of magnetic fields stabi...

  10. Crystallization of Self-Propelled Hard Discs

    Briand, G.; Dauchot, O.


    We experimentally study the crystallization of a monolayer of vibrated discs with a built-in polar asymmetry, a model system of active liquids, and contrast it with that of vibrated isotropic discs. Increasing the packing fraction ϕ , the quasicontinuous crystallization reported for isotropic discs is replaced by a transition, or a crossover, towards a "self-melting" crystal. Starting from the liquid phase and increasing the packing fraction, clusters of dense hexagonal-ordered packed discs spontaneously form, melt, split, and merge, leading to a highly intermittent and heterogeneous dynamics. For a packing fraction larger than ϕ*, a few large clusters span the system size. The cluster size distribution is monotonically decreasing for ϕ ϕ*, and is a power law at the transition. The system is, however, never dynamically arrested. The clusters permanently melt from place to place, forming droplets of an active liquid which rapidly propagate across the system. This self-melting crystalline state subsists up to the highest possible packing fraction, questioning the stability of the crystal for active discs unless it is at ordered close packing.

  11. The quiescent phase of galactic disc growth

    Aumer, Michael; Schönrich, Ralph


    We perform a series of controlled N-body simulations of growing disc galaxies within non-growing, live dark matter haloes of varying mass and concentration. Our initial conditions include either a low-mass disc or a compact bulge. New stellar particles are continuously added on near-circular orbits to the existing disc, so spiral structure is continuously excited. To study the effect of combined spiral and giant molecular cloud (GMC) heating on the discs we introduce massive, short-lived particles that sample a GMC mass function. An isothermal gas component is introduced for a subset of the models. We perform a resolution study and vary parameters governing the GMC population, the histories of star formation and radial scale growth. Models with GMCs and standard values for the disc mass and halo density provide the right level of self-gravity to explain the age velocity dispersion relation of the Solar neighbourhood (Snhd). GMC heating generates remarkably exponential vertical profiles with scaleheights that ...

  12. Structures induced by companions in galactic discs

    Kyziropoulos, P; Gravvanis, G; Patsis, P


    Using N-body simulations we study the structures induced on a galactic disc by repeated flybys of a companion in decaying eccentric orbit around the disc. Our system is composed by a stellar disc, bulge and live dark matter halo, and we study the system's dynamical response to a sequence of a companion's flybys, when we vary i) the disc's temperature (parameterized by Toomre's Q-parameter) and ii) the companion's mass and initial orbit. We use a new 3D Cartesian grid code: MAIN (Mesh-adaptive Approximate Inverse N-body solver). The main features of MAIN are reviewed, with emphasis on the use of a new Symmetric Factored Approximate Sparse Inverse (SFASI) matrix in conjunction with the multigrid method that allows the efficient solution of Poisson's equation in three space variables. We find that: i) companions need to be assigned initial masses in a rather narrow window of values in order to produce significant and more long-standing non-axisymmetric structures (bars and spirals) in the main galaxy's disc by t...

  13. Early removal of a Maverick disc prosthesis: surgical findings and morphological changes.

    François, Jens; Coessens, Ronald; Lauweryns, Philippe


    We report the case of a patient who underwent explantation of a Maverick total disc prosthesis at the L5S1 level because of severe persisting pain one year after initial implantation. Dynamic radiographic imaging studies showed good position and size of the prosthesis and no evidence of loosening. Intraoperatively residual mobility at the proximal bone-prosthesis interface was detected, as well as gross metallosis around the articulation of the total disc prosthesis. A safe and straightforward technique for the extraction of a Maverick prosthesis using a hooked instrument to hook-on the keel of the device is reported. After removal of the device, an anterior lumbar interbody fusion with subsequent posterior pedicle screw fixation and posterior bone grafting with autologous iliac bone was performed (360 degrees fusion). During this posterior procedure, severe L5S1 facet joint arthrosis was observed. Early clinical and radiographic results were good with excellent patient satisfaction.

  14. A preliminary report of patellofemoral arthroplasty in isolated patellofemoral arthritis

    GAO Xiang; XU Zheng-jian; HE Rong-xin; YAN Shi-gui; WU Li-dong


    Background Isolated patellofemoral osteoarthritis is not uncommon. Surgical treatment of isolated patellofemoral arthritis remains controversial and poses a challenging treatment dilemma. The present study aimed to evaluate the short-term results of patellofemoral arthroplasty for patients with isolated patellofemoral osteoarthritis.Methods We analyzed 11 patellofemoral arthroplasties performed from March 2006 to September 2009 in 11 patients with isolated patellofemoral arthritis. The patients comprised 2 males and 9 females with an average age of 53.7 years (range, 46-74 years). Standard weightbearing radiographs were taken in the anteroposterior, lateral, and 45° axial views.The knee pain and functional status were evaluated by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scales and American Knee Society (AKS) scores. For comparison, 23 total knee arthroplasties in 23 patients with primary tibiofemoral osteoarthritis were matched according to age, gender, bilaterality and body mass index.The duration of follow-up was 23.7 months (range, 12-47 months).Results The majority of the 11 patients experienced improvement in their patellofemoral symptoms after patellofemoral arthroplasty. The WOMAC scores improved considerably by 7.4 points with respect to pain and by 5.2 points with respect to function. The AKS scores also improved considerably by 23.9 points with respect to pain and 44.3 points with respect to function. Although the clinical outcomes after patellofemoral arthroplasty were not better than those after total knee arthroplasty, patellofemoral arthroplasty exhibited advantages in the shorter operation time, lower blood loss and increased postoperative range of motion. At the latest follow-up, there was no clinical or radiographic evidence of patellofemoral maltracking, loosening or wear.Conclusions On the basis of our experience in this relatively small series of patients with a short-term follow-up,patellofemoral arthroplasty

  15. Infected primary knee arthroplasty: Risk factors for surgical treatment failure

    Joao Gabriel Duarte Paes Pradella


    Full Text Available OBJECTIVE: To present epidemiological data and risk factors associated with surgical out-comes favorable or unfavorable for the treatment of infection in infected total knee arthroplasty. METHODS: We reviewed medical records of 48 patients who underwent treatment of primary total knee arthroplasty for infection between January 1994 and December 2008, in the Orthopedics and Traumatology Department of the Santa Casa de Misericórdia de São Paulo. The variables associated with favorable outcome of surgical treatment (debridement and retention or exchange arthroplasty in two days or unfavorable (arthrodesis or death infection. RESULTS: A total of 39 cases of infection after primary total knee arthroplasty, 22 progressed to 17 for a favorable outcome and unfavorable outcome. Early infections (OR: 14.0, 95% CI 1.5-133.2, p = 0.016 and diabetes (OR: 11.3, 95% CI 1.4-89.3, p = 0.032 were associated with arthrodesis joint and death respectively. CONCLUSION: Patients with early infection had a higher risk of developing surgical procedure with unfavorable outcome (arthrodesis and diabetics had higher odds of death after infection of primary knee arthroplasties.

  16. A review of ceramic bearing materials in total joint arthroplasty.

    Bal, B S; Garino, J; Ries, M; Rahaman, M N


    Bearings made of ceramics have ultra-low wear properties that make them suitable for total hip arthroplasty (THA) and total knee arthroplasty (TKA). When compared to cobalt chrome (CoCr)-on-polyethylene (PE) articulations, ceramics offer drastic reductions in bearing wear rates. Lower wear rates result in fewer wear particles produced by the articulating surfaces. In theory, this should reduce the risk of periprosthetic osteolysis and premature implant loosening, thereby contributing to the longevity of total joints. In addition to ceramics, other alternative bearing couples, such as highly cross-linked PE (XLPE) and metal-on-metal also offer less wear than CoCr-on-PE articulations in total joint arthroplasty. Alumina and zirconia ceramics are familiar to orthopaedic surgeons since both materials have been used in total joints for several decades. While not new in Europe, alumina-on-alumina ceramic total hips have only recently become available for widespread use in the United States from various orthopaedic implant manufacturers. As the search for the ideal total joint bearing material continues, composite materials of existing ceramics, metal-on-ceramic articulations, and new ceramic technologies will offer more choices to the arthroplasty surgeon. The objective of this paper is to present an overview of material properties, clinical applications, evolution, and limitations of ceramic materials that are of interest to the arthroplasty surgeon.

  17. Cytotoxicity Test of One-Step Self-Etching Bonding Agents by Standardized Dentin Barrier Test Using Polyurethane Discs

    Mi-Joo Kim


    Full Text Available This study was performed to standardize a dentin barrier test with the substitute and evaluate the cytotoxicity of one-step self-etching bonding agents. Each of the natural bovine dentin and polyurethane discs were 500-μm thick and were tested using a perfusion device. Following the treatment with 0.05% phenol on the natural bovine disc or three kinds of polyurethane discs—30, 40, and 50 pcf (pounds per cubic foot—cell viability of L-929 was measured by the 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay and expressed as percentages of non-treated group, respectively. A substitute showing permeability similar to that of bovine dentin was determined based on this result. Cytotoxicity test of bonding agents was performed by the selected substitute, the results of which were expressed as percentages of the control. In addition, SEM images were taken after the tests. The cell viability by 40-pcf polyurethane disc was not statistically different from that by bovine dentin disc (P > 0.05. Futurabond DC resulted in the highest cell viability and Bond force the lowest by the 40-pcf polyurethane disc (P < 0.05. The adhesives on the 40-pcf polyurethane disc changed cellular morphology with different degrees on the SEM images. This standardized test might be useful for assessing the cytotoxicity of dental materials applied to dentin before clinical applications.

  18. Discs of Satellites: the new dwarf spheroidals

    Metz, Manuel; Jerjen, Helmut


    The spatial distributions of the most recently discovered ultra faint dwarf satellites around the Milky Way and the Andromeda galaxy are compared to the previously reported discs-of-satellites (DoS) of their host galaxies. In our investigation we pay special attention to the selection bias introduced due to the limited sky coverage of SDSS. We find that the new Milky Way satellite galaxies follow closely the DoS defined by the more luminous dwarfs, thereby further emphasizing the statistical significance of this feature in the Galactic halo. We also notice a deficit of satellite galaxies with Galactocentric distances larger than 100 kpc that are away from the disc-of-satellites of the Milky Way. In the case of Andromeda, we obtain similar results, naturally complementing our previous finding and strengthening the notion that the discs-of-satellites are optical manifestations of a phase-space correlation of satellite galaxies.


    Sahiba Bedi


    Full Text Available Melanocytoma of the optic disc is a rare ophthalmic tumour that arises from melanocytes and is a variant of the melanocytic nevus. It occurs on the optic disc and often extends into the peripapillary retina and choroid. It appears as a dark brown or black lesion, typically small and is almost always unilateral. Although traditionally believed to be a relatively stationary lesion, it is now known to exhibit minor enlargement in 10–15% of cases and can cause minor visual loss by a variety of mechanisms. 1-2% cases can transform to malignant melanoma. We present a case report of a 65-year-old female whose dilated fundus examination of the right eye revealed a circular, pigmented and elevated lesion about 1.5 mm in size covering almost whole of the optic nerve head except for the superior rim, suggestive of optic disc melanocytoma.

  20. Signatures of massive collisions in debris discs

    Kral, Quentin; Augereau, Jean-Charles; Boccaletti, Anthony; Charnoz, Sebastien


    Violent stochastic collisional events have been invoked as a possible explanation for some debris discs displaying pronounced asymmetries or having a great luminosity excess. So far, no thorough modelling of the consequences of such events has been carried out, mainly because of the extreme numerical challenge of coupling the dynamical and collisional evolution of dust. We perform the first fully self-consistent modelling of the aftermath of massive breakups in debris discs. We follow the collisional and dynamical evolution of dust released after the breakup of a Ceres-sized body at 6 AU from its central star. We investigate the duration, magnitude and spatial structure of the signature left by such a violent event, as well as its observational detectability. We use the recently developed LIDT-DD code (Kral et al., 2013), which handles the coupled collisional and dynamical evolution of debris discs. The main focus is placed on the complex interplay between destructive collisions, Keplerian dynamics and radiat...

  1. Black hole feedback from thick accretion discs

    Sadowski, Aleksander; Abramowicz, Marek A; Narayan, Ramesh


    We study energy flows in geometrically thick accretion discs, both optically thick and thin, using general relativistic, three-dimensional simulations of black hole accretion flows. We find that for non-rotating black holes the efficiency of the total feedback from thick accretion discs is $3\\%$ - roughly half of the thin disc efficiency. This amount of energy is ultimately distributed between outflow and radiation, the latter scaling weakly with the accretion rate for super-critical accretion rates, and returned to the interstellar medium. Accretion on to rotating black holes is more efficient because of the additional extraction of rotational energy. However, the jet component is collimated and likely to interact only weakly with the environment, whereas the outflow and radiation components cover a wide solid angle.

  2. Satellites in discs regulating the accretion luminosity

    Syer, D; Syer, Dave; Clarke, Cathie


    We demonstrate, using a simple analytic model, that the presence of a massive satellite can globally modify the structure and emission properties of an accretion disc to which it is tidally coupled. We show, using two levels of numerical approximation, that the analytic model gives reasonable results. The results are applicable to two astrophysical situations. In the case of an active galactic nucleus, we consider the case of a \\sim 10^3\\Msun compact companion to the central black-hole and show that it could modulate the emitted spectrum on a timescale of \\sim10^5 years. In the case of a T Tauri accretion disc, a satellite such as a sub-dwarf or giant planet could modify the disc spectral energy distribution over a substantial fraction of the T Tauri star lifetime.

  3. The debris disc around HIP 17439

    Schüppler, Christian; Löhne, Torsten; Krivov, Alexander


    In the framework of the Herschel Open Time Key Programme DUNES the debris disc around the K2 V star HIP 17439 was observed. In PACS images the disc emission is spatially clearly extended. A simultaneous analysis of photometric observations and radial brightness profiles from the resolved images provides valuable hints for the disc structure. In an analytical model we adopted power laws for the size and radial distribution of the circumstellar dust and tested two different scenarios: (1) a broad dust ring with a radial extent of about 200AU, (2) two independent dust rings separated by a gap of several tens of AU. Both models fit the spectral energy distribution and the radial profiles quite well. In case (1) the parameters found are consistent with dust stemming from an outer planetesimal belt at ~140AU and strong transport mechanisms that drag the particles inward. Model (2) would imply two planetesimal belts, producing a narrow inner and wider outer distribution of dust.

  4. Inferior outcome after hip resurfacing arthroplasty than after conventional arthroplasty. Evidence from the Nordic Arthroplasty Register Association (NARA) database, 1995 to 2007

    Johanson, Per-Erik; Fenstad, Anne Marie; Furnes, Ove;


    The reported outcomes of hip resurfacing arthroplasty (HRA) vary. The frequency of this procedure in Denmark, Norway, and Sweden is low. We therefore determined the outcome of HRA in the NARA database, which is common to all 3 countries, and compared it to the outcome of conventional total hip...

  5. Effects of disc midplane evolution on CO snowline location

    Panić, O.; Min, M.


    Temperature changes in the planet forming disc midplanes carry important physico-chemical consequences, such as the effect on the locations of the condensation fronts of molecules - the snowlines. Snowlines impose major chemical gradients and possibly foster grain growth. The aim of this paper is to understand how disc midplane temperature changes with gas and dust evolution, and identify trends that may influence planet formation or allow to constrain disc evolution observationally. We calculate disc temperature, hydrostatic equilibrium and dust settling in a mutually consistent way from a grid of disc models at different stages of gas loss, grain growth and hole opening. We find that the CO snowline location depends very strongly on disc properties. The CO snowline location migrates closer to the star for increasing degrees of gas dispersal and dust growth. Around a typical A type star, the snowline can be anywhere between several tens and a few hundred au, depending on the disc properties such as gas mass and grain size. In fact, gas loss is as efficient as dust evolution in settling discs, and flat discs may be gas-poor counterparts of flared discs. Our results, in the context of different pre-main sequence evolution of the luminosity in low- and intermediate-mass stars suggests very different thermal (and hence chemical) histories in these two types of discs. Discs of T Tauri stars settle and cool down while discs of Herbig Ae stars may remain rather warm throughout the pre-main sequence.

  6. Effect of continuous lumbar traction on the size of herniated disc material in lumbar disc herniation.

    Ozturk, Bulent; Gunduz, Osman Hakan; Ozoran, Kursat; Bostanoglu, Sevinc


    We investigated the effects of continuous lumbar traction in patients with lumbar disc herniation on clinical findings, and size of the herniated disc measured by computed tomography (CT). In this prospective, randomized, controlled study, 46 patients with lumbar disc herniation were included, and randomized into two groups as the traction group (24 patients), and the control group (22 patients). The traction group was given a physical therapy program and continuous lumbar traction. The control group was given the same physical therapy program without traction, for the same duration of time. Data for the clinical symptoms and signs were collected before and after the treatment together with calculation of a herniation index, from the CT images that showed the size of the herniated disc material. In the traction group, most of the clinical findings significantly improved with treatment. Size of the herniated disc material in CT decreased significantly only in the traction group. In the traction group the herniation index decreased from 276.6+/-129.6 to 212.5+/-84.3 with treatment (p0.05). Patients with greater herniations tended to respond better to traction. In conclusion, lumbar traction is both effective in improving symptoms and clinical findings in patients with lumbar disc herniation and also in decreasing the size of the herniated disc material as measured by CT.

  7. Cometary ices in forming protoplanetary disc midplanes

    Drozdovskaya, Maria N.; Walsh, Catherine; van Dishoeck, Ewine F.; Furuya, Kenji; Marboeuf, Ulysse; Thiabaud, Amaury; Harsono, Daniel; Visser, Ruud


    Low-mass protostars are the extrasolar analogues of the natal Solar system. Sophisticated physicochemical models are used to simulate the formation of two protoplanetary discs from the initial prestellar phase, one dominated by viscous spreading and the other by pure infall. The results show that the volatile prestellar fingerprint is modified by the chemistry en route into the disc. This holds relatively independent of initial abundances and chemical parameters: physical conditions are more important. The amount of CO2 increases via the grain-surface reaction of OH with CO, which is enhanced by photodissociation of H2O ice. Complex organic molecules are produced during transport through the envelope at the expense of CH3OH ice. Their abundances can be comparable to that of methanol ice (few per cent of water ice) at large disc radii (R > 30 au). Current Class II disc models may be underestimating the complex organic content. Planet population synthesis models may underestimate the amount of CO2 and overestimate CH3OH ices in planetesimals by disregarding chemical processing between the cloud and disc phases. The overall C/O and C/N ratios differ between the gas and solid phases. The two ice ratios show little variation beyond the inner 10 au and both are nearly solar in the case of pure infall, but both are subsolar when viscous spreading dominates. Chemistry in the protostellar envelope en route to the protoplanetary disc sets the initial volatile and prebiotically significant content of icy planetesimals and cometary bodies. Comets are thus potentially reflecting the provenances of the midplane ices in the solar nebula.

  8. Pelvic Discontinuity Caused by Acetabular Overreaming during Primary Total Hip Arthroplasty

    Iori Takigami


    Full Text Available Intraoperative acetabular fracture is a rare complication of primary total hip arthroplasty (THA, typically occurring during impaction of the cementless acetabular component. Here we report an unusual case of pelvic discontinuity caused by overreaming of the acetabulum during primary THA. Restoration of posterior columnar continuity was achieved with an autologous fibular graft and a reconstruction plate. Wall defects and cavitary defects were reconstructed with metal mesh and femoral head allograft, followed by placement and fixation of a Kerboull-type acetabular reinforcement device. Previous reports of acetabular fracture during THA have indicated that it has a relatively good prognosis without extensive treatment. However, to our knowledge, there has been no report of pelvic discontinuity necessitating acetabular reconstruction surgery as an intraoperative complication of primary THA.

  9. Cells and Biomaterials for Intervertebral Disc Regeneration

    Grad, Sibylle


    Disorders related to the intervertebral disc (IVD) are common causes of morbidity and of severe life quality deterioration. IVD degeneration, although in many cases asymptomatic, is often the origin of painful neck and back diseases. In Western societies IVD related pain and disability account for enormous health care costs as a result of work absenteeism and thus lost production, disability benefits, medical and insurance expenses. Although only a small percentage of patients with disc disorders finally will undergo surgery, spinal surgery has been one of the fastest growing disciplines in th

  10. Natural course of lumber disc herniation

    Tokioka, Takamitsu; Shimada, Kimio; Tanaka, Yuzo; Oshige, Toshihisa; Miyakoshi, Koichi [Okayama Rosai Hospital (Japan)


    Thirty-two cases of lumbar disc herniation were sequentially followed by MR imagings in order to ascertain its natural course. Herniation consisted of protrusion in 6 cases, extrusion in 13 cases, and sequestration in 13 cases. We analysed the durations until the herniation regressed more than 50% of its A-P diameter. The mean duration was 8.2 months for extrusion, and 5.3 months for sequestration. Only 2 cases of protrusion regressed within 12 months. Huge disc herniations with central protrusion in particular showed slight spontaneous regression. (author)

  11. Disc-Capped ZnO Nanocombs

    LI Xin; XU chun-xiang; ZHU Guang-Ping; YANG Yi; LIU Jin-Ping; SUN Xiao-Wei; CUI Yi-Ping


    Nanocombs with a disc cap structure of ZnO have been synthesized on si substrates by using pure Zinc powders as the source materials based on a vapour-phase transport process.The morphology and the microstructure are investigated by a scanning electron microscopy and x-ray diffraction.Based on the transmission electron microscopy and selected area electron diffraction analysis,the growth directions of three representative parts,nanoribbon stem,nanorod branch and nanodisc cap of the nanocomb are revealed.The growth mechanism of the disc-capped nanocombs is discussed based on the self-catalyzed vapour-liquid-solid process.

  12. Iliopsoas impingement after revision total hip arthroplasty treated with iliopsoas muscle transection.

    Morohashi, Itaru; Homma, Yasuhiro; Kanda, Akio; Yamamoto, Yasuhiro; Obata, Hiroyuki; Mogami, Atsuhiko; Obayashi, Osamu; Kaneko, Kazuo


    Iliopsoas tendinitis after revision total hip arthroplasty (THA) is rare and its etiology and optimal treatment are still unclear. We report a case of iliopsoas impingement after revision THA with a Kerboull acetabular reinforcement device requiring two-level iliopsoas muscle transection. A 70-year-old woman presented to our hospital complaining of debilitating right groin pain after revision THA with a Kerboull reinforcement device. She had undergone multiple hip operations after experiencing a pelvic fracture in a motor vehicle accident. A lidocaine nerve block at the level of the Kerboull device resulted in temporary but marked reduction in pain and a diagnosis of psoas impingent. We performed surgery via an anterior approach to release the iliopsoas muscle from the lesser trochanter. After iliopsoas tenotomy was performed, the muscle was still under high tension because of dense adhesions. Repeat transection of the iliopsoas muscle at the level of the anterior branch of the Kerboull device resulted in loosening of the iliopsoas muscle and resolution of impingement. Postoperatively, the patient's groin pain completely disappeared, and she can now walk with a single cane and is satisfied with her result. Adhesions around the iliopsoas muscle likely contributed to the patient's groin pain. Open surgery to perform complete release of iliopsoas muscle impingement should be considered in patients with pain after revision THA. We reported a patient with Iliopsoas tendinitis after revision THA requiring two-level iliopsoas muscle transection.

  13. Radiographic and scintigraphic evaluation of total knee arthroplasty

    Schneider, R.; Soudry, M.


    Various radiographic and scintigraphic methods are used to supplement clinical findings in the evaluation of total knee arthroplasty and its complications. Serial roentgenograms offer reliable information for diagnosing mechanical loosening. Wide and extensive radiolucency at the cement-bone interface and shift in position and alignment of prosthetic components can be seen in almost all cases by the time revision is necessary. Radiographic abnormalities are usually not present in acute infection, but are often present in chronic infection. Bone scanning has a high sensitivity for diagnosis of infection or loosening, but is nonspecific because increased uptake is often present around asymptomatic total knee arthroplasties with normal radiographs. Differential bone and Gallium scanning and scanning with Indium 111-labeled leukocytes have a greater specificity for diagnosis of infection than does bone or Gallium scanning alone. Routine radiographic and scintigraphic studies have shown a high incidence of deep vein thrombosis in the calf after total knee arthroplasty. Clinically significant pulmonary embolization is infrequent.

  14. Cobalt toxicity after McKee hip arthroplasty.

    Jones, D A; Lucas, H K; O'Driscoll, M; Price, C H; Wibberley, B


    The significance of cobalt as a cause of symptoms after McKee hip arthroplasty is discussed. Seven patients are described in whom such arthroplasties. became unsatisfactory after periods varying from nine months to four years. Six of these patients were cobalt-positive but nickel- and chrome-negative on patch testing. Macroscopic and histological necrosis of bone, muscle and joint capsule around the prostheses was found in five patients whose hips were explored. The symptoms were progressive pain, a feeling of instability, and in two cases spontaneous dislocation. Radiological features included acetabular fracture, bone resorption, loosening and dislocation of the prosthesis. Increased cobalt concentrations (determined by atomic absorption spectrophotometry) in the urine of four patients and in a variety of tissues in one patient are presented. Patch testing is recommended in the investigation of patients with troublesome McKee hip arthroplasties

  15. Stemless shoulder arthroplasty-current results and designs.

    Churchill, R Sean; Athwal, George S


    Stemless shoulder arthroplasty was originally introduced in 2004 by a single manufacturer. Now, over a decade later, numerous designs are available outside the USA, but as yet, only one implant has been cleared by the Food and Drug Administration (FDA) and is available for use within the USA. Often referred to as "canal sparing," these implants are designed for metaphyseal fixation to minimize humeral bone removal, avoid intraoperative and postoperative humeral fracture complications, and to decrease morbidity associated with revision operations. Recently, the second generation of stemless arthroplasty, a convertible implant allowing use in either anatomic or reverse arthroplasty configuration, was released for use outside the USA. This paper will review the available designs, reported results, and raise potential concerns for this emerging technology.

  16. Shoulder arthroplasty. Part 1: Prosthesis terminology and classification

    Sheridan, B.D., E-mail: [Department of Orthopaedic Surgery, Bristol Royal Infirmary, Bristol (United Kingdom); Ahearn, N.; Tasker, A.; Wakeley, C.; Sarangi, P. [Department of Orthopaedic Surgery, Bristol Royal Infirmary, Bristol (United Kingdom)


    Shoulder arthroplasty is the third most common joint replacement procedure in the UK, and there are a number of different implant options available to surgeons to treat a variety of shoulder disorders. With an increasing burden placed on clinical follow-up, more patients are remaining under the care of their general practitioners and musculoskeletal triage assessment services and are not necessarily being seen by specialists. Referrals to orthopaedic specialists are therefore often prompted by radiological reports describing evidence of implant failure. This article is the first of two reviews on shoulder arthroplasty, concentrating on implant features and the indications for their use. The second article will address the modes of failure of shoulder arthroplasty and describe the relevant associated radiological features.

  17. Cementless revision for infection following total hip arthroplasty.

    Mitchell, Philip A; Masri, Bassam A; Garbuz, Donald S; Greidanus, Nelson V; Duncan, Clive P


    Eradication of chronic infection complicating total hip arthroplasty requires removal of all infected, devitalized and foreign tissue, including the arthroplasty components. Reimplantation into a sterile bed is the goal of treatment in most patients and successful reimplantation yields better functional results than excision arthroplasty. Reimplantation may be performed at the same stage as débridement as part of a single-stage procedure, using cemented components with antibiotic-loaded cement. Alternatively, a two-stage procedure may be performed so that the débridement and reimplantation are separated by a period of antibiotic delivery, both locally and systemically. The results of these treatment regimens and the rationale for cementless reconstruction at the second stage of a two-stage treatment protocol are important considerations in the treatment of periprosthetic infection.

  18. Arthroscopic bursectomy for recalcitrant trochanteric bursitis after hip arthroplasty.

    Van Hofwegen, Christopher; Baker, Champ L; Savory, Carlton G; Baker, Champ L


    This study evaluated the use of arthroscopic bursectomy for pain relief in patients with trochanteric bursitis after hip arthroplasty. In this retrospective case series of 12 patients undergoing arthroscopic treatment of recalcitrant trochanteric bursitis after hip arthroplasty, outcomes were assessed via phone interview with a numeric pain rating scale from 1 to 10 and were compared with preoperative pain ratings. Patients were asked the percentage of time they had painless hip function and whether they would have the surgery again. At an average 36-month follow-up (range, 4-85 months), the average numeric pain scale rating improved from 9.3 to 3.3. At an average of 62% of the time, patients had painless use of the hip. Ten of 12 patients in the study felt the pain relief gained was substantial enough to warrant having procedure again. In these patients, arthroscopic bursectomy was a viable option for patients with recalcitrant bursitis after hip arthroplasty.

  19. Early total hip arthroplasty for severe displaced acetabular fractures

    YANG Shu-hua; ZHANG Yu-kun; XU Wei-hua; LI Jin; LIU Guo-hui; YANG Cao; LIU Yong; TIAN Hong-tao


    Objective : To investigate the effect of early total hip arthroplasty for severe displaced acetabular fractures.Methods: Total hip arthroplasty was performed on 17 cases of severe fracture of the acetabulum from 1997 to 2003. The mean follow-up was 2.1 years (1-6 years) and the average period from fracture to operation was 8 days (5-21 day). The average age of the patients was 53 years (26-69 years).Results: At the final follow-up the Harris hip score averaged 82(69-100) points and 15 cases have got a good outcome. There was one case of heterotopic bone formation. There were no radiographic evidences of late loosening of the prosthesis. One patient had severe central displacement of the cup.Conclusions: In patients with severe displaced acetabular fractures, particularly in elderly patients, early total hip arthroplasty is probably an alternative efficient way to achieve a painless and stable hip.

  20. Association between trochanteric bursitis, osteoarthrosis and total hip arthroplasty,

    Carlos Roberto Schwartsmann


    Full Text Available OBJECTIVE: this was an epidemiological study on trochanteric bursitis at the time of performing total hip arthroplasty.METHODS: sixty-two sequential patients who underwent total hip arthroplasty due to osteoarthrosis, without any previous history of trochanteric bursitis, were evaluated. The bursas were collected and evaluated histologically.RESULTS: there were 35 female patients (56.5% and 27 male patients (43.5%, with a mean age of 65 years (±11. Trochanteric bursitis was conformed histologically in nine patients (14.5%, of whom six were female (66.7% and three were male (33.3%.CONCLUSIONS: 14.5% of the bursas analyzed presented inflammation at the time that the primary total hip arthroplasty due to osteoarthrosis was performed, and the majority of the cases of bursitis were detected in female patients.

  1. Multimedia Archiving: Videotape, Compact Disc (CD), Digital Versatile Disc (DVD), and Blu-Ray Disc (BD) Media


    4 inch U-Matic or Betacam tapes, it is necessary to inventory the archives several times a year to determine which products are no longer worth...Philips, Samsung , Sharp, Sony, TDK and Thomson. The Blu-ray disc is based on an industry standard format supported by 190 companies and is written

  2. Is reverse total shoulder arthroplasty a feasible treatment option for failed shoulder arthroplasty? A retrospective study of 44 cases with special regards to stemless and stemmed primary implants.

    Holschen, M; Franetzki, B; Witt, K-A; Liem, D; Steinbeck, J


    Is reverse total shoulder arthroplasty a feasible treatment option for failed shoulder arthroplasty? A retrospective study of 44 cases with special regards to stemless and stemmed primary implants. Due to humeral or glenoid bone-loss and rotator cuff insufficiency reverse total shoulder arthroplasty often means the only remaining treatment option in revision shoulder arthroplasty. This study investigates the clinical outcome of patients treated with a reverse total shoulder in revision cases with special regard to stemless and stemmed primary implants. From 2010 to 2012 60 failed shoulder arthroplasties were converted to reverse total shoulder arthroplasty. Forty-four patients were available for follow-up after a mean of 24 months. Patients were assessed with X-rays, Constant- and ASES Score and a questionnaire about their subjective satisfaction. The total number of observed complications was seven (16%). Ninety-eight percent of the patients were satisfied with their clinical result. Patients achieved a mean normalized constant score of 70.2% and a mean ASES Score of 65.3. Patients with stemless primary implants achieved a higher normalized constant score than patients with stemmed primary implants (82 vs. 61.8%; p = 0009). Reverse total shoulder arthroplasty provides satisfactory clinical results and a high patient satisfaction in revision shoulder arthroplasty. The complication rate needs to be considered and discussed with the patient prior to surgery. Presence or absence of a stem of revised shoulder arthroplasties interferes with the outcome. LEVEL OF EVIDENCE IV: (Retrospective study).

  3. Be discs in binary systems I. Coplanar orbits

    Panoglou, Despina; Vieira, Rodrigo G; Cyr, Isabelle H; Jones, Carol E; Okazaki, Atsuo T; Rivinius, Thomas


    Be stars are surrounded by outflowing circumstellar matter structured in the form of decretion discs. They are often members of binary systems, where it is expected that the decretion disc interacts both radiatively and gravitationally with the companion. In this work we study how various orbital (period, mass ratio, eccentricity) and disc (viscosity) parameters affect the disc structure in coplanar systems. We simulate such binaries with the use of a smoothed particle hydrodynamics code. The main effects of the secondary on the disc are its truncation and the accumulation of material inwards of truncation. In circular or nearly circular prograde orbits, the disc maintains a rotating, constant in shape, configuration, which is locked to the orbital phase. The disc is smaller in size, more elongated and more massive for low viscosity parameter, small orbital separation and/or high mass ratio. Highly eccentric orbits are more complex, with the disc structure and total mass strongly dependent on the orbital phas...

  4. Relationship of condylar position to disc position and morphology

    Incesu, L.; Taskaya-Yilmaz, N. E-mail:; Oeguetcen-Toller, M.; Uzun, E


    Introduction/objective: The purpose of this study was to assess whether condylar position, as depicted by magnetic resonance imaging, was an indicator of disc morphology and position. Methods and material: One hundred and twenty two TMJs of 61 patients with temporomandibular joint disorder were examined. Condylar position, disc deformity and degree of anterior disc displacement were evaluated by using magnetic resonance imaging. Results and discussion: Posterior condyle position was found to be the main feature of temporomandibular joints with slight and moderate anterior disc displacement. No statistical significance was found between the condylar position, and reducing and nonreducing disc positions. On the other hand, superior disc position was found to be statistically significant for centric condylar position. Conclusion: It was concluded that posterior condyle position could indicate anterior disc displacement whereas there was no relation between the position of condyle and the disc deformity.


    Huo Yingying; Sun Daochun


    In this article, the authors define the derived function of an algeboidal function in the unit disc, prove it is an algabriodal function, and study the order of algebroidal function and that of its derived function in unit circular disc.

  6. Post-Main Sequence Evolution of Debris Discs

    Bonsor, Amy


    The population of debris discs on the main sequence is well constrained, however very little is known about debris discs around evolved stars. In this work we provide a theoretical framework that considers the effects of stellar evolution on debris discs; firstly considering the evolution of an individual disc from the main sequence through to the white dwarf phase, then extending this to the known population of debris discs around main sequence A stars. It is found that discs around evolved stars are harder to detect than on the main sequence. In the context of our models discs should be detectable with Herschel or Alma on the giant branch, subject to the uncertain effect of sublimation on the discs. The best chances are for hot young white dwarfs, fitting nicely with the observations e.g the helix nebula (Su et al. 2007) and 9 systems presented by Chu & Bilikova.

  7. Revision reverse shoulder arthroplasty in failed shoulder arthroplasties for rotator cuff deficiency



    Purpose the aim of this systematic literature review is to report clinical outcomes of reverse shoulder arthroplasty (RSA) used as a revision surgery following failure of the primary implant due to rotator cuff insufficiency. Methods a systematic review was performed using the following key words: revision, shoulder, rotator cuff deficiency, outcome assessment, treatment outcome, complications. Studies eligible for inclusion in the review were clinical trials investigating patients in whom a primary shoulder arthroplasty implant with an incompetent rotator cuff was replaced with a reverse shoulder prosthesis. Results nine articles were identified and further reviewed. The results refer to a total of 226 shoulders that were treated with RSA as revision surgery. The patients in the studies had a mean age ranging from 64 to 72 years and the longest follow-up was 3.8 years. Improvements in function and reduction of pain were shown by many studies, but the mean Constant score ranged from 44.2 to 56. High complication rates (of up to 62%) were recorded, and a mean reoperation rate of 27.5%. Conclusions RSA as revision surgery for patients with rotator cuff deficiency is a valid option, and often the only solution available, but it should be limited to elderly patients with poor function and severe pain. Level of evidence level IV, systematic review of level I–IV studies. PMID:26151037

  8. Functional Outcomes of Revision Total Knee Arthroplasty Following Failed Unicompartmental Knee Arthroplasty

    Chris Ironside


    Full Text Available Introduction: Unicompartmental knee arthroplasty (UKA can be used to treat medial compartment osteoarthritis of the knee. Some of these knees will eventually fail, and need to be revised. There is controversy about using UKA in younger patients as a definitive procedure or as a means to delay total knee arthroplasty (TKA because the outcomes of subsequent revision surgery may be inferior to a primary TKA. Methods: We retrospectively reviewed a series of 46 revision TKA patients following failed UKA (UKA revisions using functional outcomes questionnaires and compared the results with a cohort of age and gender matched primary TKA patients. Our hypothesis was that UKA revision surgery would be inferior to primary TKA surgery. Results: Data was collected on 33 knees after a mean follow-up period of five years. There was no significant difference in the Oxford Knee Score (33.7 vs 37.1, p = 0.09 or the Western Ontario and MacMasters Universities Arthritis Index (WOMAC (24.8 vs. 19.1, p = 0.22. A subgroup analysis demonstrated that UKAs, which fail early, are more likely to produce an inferior outcome following revision surgery than those that survive more than five years. Discussion: We conclude that UKA can be used effectively in appropriately selected patients, as the functional outcome of their subsequent revision to TKA is not significantly inferior to a primary TKA.

  9. Temporomandibular joint disc; a proposed histopathological degeneration grading score system


    Summary. Aims: The purpose of this study was to draw up a TMJ disc histopathological score that is a semiquantitative transcription of the entire spectrum of TMJ disc degenerative diseases related to changes in disc tissue, and then validate the proposed grading, in order to contribute to a standardized histopathological diagnosis. Methods: Sections from sixty two temporomandibular joint disc specimens affected by tissue degenerative changes and stained with Hematox...

  10. MRI and discography in traumatic intervertebral disc lesions

    Ghanem, Nadir; Uhl, Markus; Elgeti, Florian; Pache, Gregor; Kotter, Elmar; Langer, Mathias [University Hospital Freiburg, Departments of Diagnostic Radiology, Freiburg (Germany); Mueller, Christoph; Markmiller, Max [University Hospital Freiburg, Traumatology, Freiburg (Germany)


    In this study we evaluated magnetic resonance imaging (MRI) in trauma patients for assessing traumatised adjacent discs of fractured vertebrae before dorsoventral stabilisation. In a prospective study, MRI of 54 discs was performed with a 1.5-T MRI unit. The preoperative MRI with sagittal T1-W-SE and T2-W-TSE was compared to intraoperative discography, which was carried out on both intervertebral discs adjacent to the fractured vertebrae. Signal alterations, morphological changes in the adjacent discs, fractured vertebrae and associated ligament injuries were evaluated. In 47/54 (87%) of the intervertebral discs, the results of both imaging findings were concordant. The discs adjoining vertebral fractures were normal in 18 cases. Regarding the positive concordant imaging findings, MRI and discography revealed traumatised adjacent cranial and caudal discs in 22 discs. In 7 cases, only the cranial adjacent disc was affected. Moreover, 17 cases of intradiscal bleeding, 13 intraosseous herniations into the fractured vertebrae and 20 anuluar tears were visualised in MRI. Associated ligament injuries were detected in 18 cases. Findings were discordant in eight discs. In six discs, MRI was abnormal, demonstrating signal alterations suggestive of positive imaging findings, whereas discography demonstrated no disc injury. MRI failed to detect disc injury in two discs, whereas discography was positive, showing an irregular intradiscal contrast media distribution. MRI, as a non-invasive method for assessing fractures of the thoraco-lumbar spine, may detect traumatised adjacent intervertebral discs. MRI is superior to intraoperative discography. The performance of MRI of the thoraco-lumbar spine is recommended before dorsoventral stabilisation in trauma patients, as it can reveal additional preoperative information such as fractures, disc and associated ligament injuries. (orig.)

  11. Oxidized Zirconium Bearing Surfaces in Total Knee Arthroplasty: Lessons Learned.

    Schüttler, Karl Friedrich; Efe, Turgay; Heyse, Thomas J; Haas, Steven B


    Polyethylene wear in total knee arthroplasty is a still unsolved problem resulting in osteolysis and long-term failure of knee joint replacement. To address the problem of polyethylene wear, research aimed for an optimal implant design and for an optimal combination of bearing surfaces. Oxidized zirconium was introduced to minimize surface wear and thus potentially increase long-term implant survival. This review comprises the current literature related to in vitro and in vivo studies evaluating performance of oxidized zirconium total knee arthroplasty and results from retrieval analyses.

  12. History and factors of survival of total hip arthroplasty.

    Kolundžić, Robert; Trkulja, Vladimir; Orlić, Dubravko


    Since the 1960s total hip arthroplasty (THA) has represented one of the greatest accomplishments in orthopedic surgery. It improves the functionality, working ability and quality of life of patients with non-functional hip joint due to various reasons. This article reviews general and regional history of THA, current knowledge and concepts regarding the long-term outcomes of the procedure and emphasizes the need for establishing national (and international) THA registries as an essential way of gathering data critical for decision making in daily practice as well as in defining national healthcare policies in respect to arthroplasty procedures.

  13. Shoulder arthroplasty. Part 2: Normal and abnormal radiographic findings

    Sheridan, B.D., E-mail: [Department of Orthopaedic Surgery, Bristol Royal Infirmary, Bristol (United Kingdom); Ahearn, N.; Tasker, A.; Wakeley, C.; Sarangi, P. [Department of Orthopaedic Surgery, Bristol Royal Infirmary, Bristol (United Kingdom)


    Frequently, the decision made by general practitioners or musculoskeletal triage assessment services to refer patients for specialist review is initiated by a radiological report. Following shoulder arthroplasty it is important to ensure that any patient with asymptomatic evidence of a failing prosthesis is referred for review so that revision surgery can be contemplated and planned before the situation becomes unsalvageable. The first paper in this series described the various types of shoulder arthroplasty and indications for each. This follow-up paper will concentrate on their modes of failure and the associated radiographic features, and is aimed at radiology trainees and non-musculoskeletal specialist radiologists.

  14. Resurfacing shoulder arthroplasty for the treatment of severe rheumatoid arthritis

    Voorde, Pia C Ten; Rasmussen, Jeppe V; Olsen, Bo S


    BACKGROUND AND PURPOSE: There is no consensus on which type of shoulder prosthesis should be used in patients with rheumatoid arthritis (RA). We describe patients with RA who were treated with shoulder replacement, regarding patient-reported outcome, prosthesis survival, and causes of revision...... with adjustment for age, sex, and previous surgery. RESULTS: During the study period, 167 patients underwent shoulder arthroplasty because of rheumatoid arthritis, 80 (48%) of whom received RHA and 34 (26%) of whom received SHA. 16 patients were treated with total stemmed shoulder arthroplasty (TSA), and 24 were...

  15. Microbiological diagnosis in revision of infected knee arthroplasties in Denmark

    Lindberg-Larsen, Martin; Pitter, Frederik Taylor; Voldstedlund, Marianne


    BACKGROUND: Revision of infected knee arthroplasties is associated with high failure rates (30-40%). An understanding of the microbiology is important to optimize treatment and outcome. We describe microbiological diagnostic practice and diagnosis in revision of infected knee arthroplasties....... METHODS: One hundred and two partial revisions (open debridement and exchange of tibial insert) and 213 two-stage procedures performed due to infection in 275 patients from 1 July 2011 to 30 June 2013 were included and analysed by linkage to data from a nationwide registry on microbiological test results...

  16. Post-irradiation examinations and high-temperature tests on undoped large-grain UO2 discs

    Noirot, J.; Pontillon, Y.; Yagnik, S.; Turnbull, J. A.


    Within the Nuclear Fuel Industry Research (NFIR) programme, several fuel variants -in the form of thin circular discs - were irradiated in the Halden Boiling Water Reactor (HBWR) at burn-ups up to ∼100 GWd/tHM. The design of the fuel assembly was similar to that used in other HBWR programmes: the assembly contained several rods with fuel discs sandwiched between Mo discs, which limited temperature differences within each fuel disc. One such variant was made of large-grain UO2 discs (3D grain size = ∼45 μm) which were subjected to three burn-ups: 42, 72 and 96 GWd/tHM. Detailed characterizations of some of these irradiated large-grain UO2 discs were performed in the CEA Cadarache LECA-STAR hot laboratory. The techniques used included electron probe microanalysis (EPMA), scanning electron microscopy (SEM) and secondary ion mass spectrometry (SIMS). Comparisons were then carried out with more standard grain size UO2 discs irradiated under the same conditions. Examination of the high burn-up large-grain UO2 discs revealed the limited formation of a high burn-up structure (HBS) when compared with the standard-grain UO2 discs at similar burn-up. High burn-up discs were submitted to temperature transients up to 1200 °C in the heating test device called Merarg at a relatively low temperature ramp rate (0.2 °C/s). In addition to the total gas release during these tests, the release peaks throughout the temperature ramp were monitored. Tests at 1600 °C were also conducted on the 42 GWd/tHM discs. The fuels were then characterized with the same microanalysis techniques as those used before the tests, to investigate the effects of these tests on the fuel's microstructure and on the fission gas behaviour. This paper outlines the high resistance of this fuel to gas precipitation at high temperature and to HBS formation at high burn-up. It also shows the similarity of the positions, within the grains, where HBS forms at high burn-up and where bubbles appear during the low

  17. Muscular strength after total hip arthroplasty

    Winther, Siri B; Husby, Vigdis S; Foss, Olav A; Wik, Tina S; Svenningsen, Svein; Engdal, Monika; Haugan, Kristin; Husby, Otto S


    Background and purpose Minimizing the decrease in muscular strength after total hip arthroplasty (THA) might allow patients to recover faster. We evaluated muscular strength in patients who were operated on using 3 surgical approaches. Patients and methods In a prospective cohort study, 60 patients scheduled for primary THA were allocated to the direct lateral, posterior, or anterior approach. Leg press and abduction strength were evaluated 2 weeks or less preoperatively, 2 and 8 days postoperatively, and at 6-week and 3-month follow-up. Results Differences in maximal strength change were greatest after 2 and 8 days. The posterior and anterior approaches produced less decrease in muscular strength than the direct lateral approach. 6 weeks postoperatively, the posterior approach produced greater increase in muscular strength than the direct lateral approach, and resulted in a greater increase in abduction strength than the anterior approach. At 3-month follow-up, no statistically significant differences between the groups were found. The operated legs were 18% weaker in leg press and 15% weaker in abduction than the unoperated legs, and the results were similar between groups. Interpretation The posterior and anterior approaches appeared to have the least negative effect on abduction and leg press muscular strength in the first postoperative week; the posterior approach had the least negative effect, even up to 6 weeks postoperatively. THA patients have reduced muscle strength in the operated leg (compared to the unoperated leg) 3 months after surgery. PMID:26141371

  18. Postoperative pyrexia after arthroplasty - when to panic ?

    Agarwala Sanjay


    Full Text Available Background: Success of arthroplasty is contingent on a clear understanding of the potential complications. Today with improved methods of sepsis control, incidence of joint sepsis has dropped to less than 2%. Despite this fever is still common in the early post-operative period. Methods: We reviewed 184 consecutive hip and knee replacement surgeries for incidence and clinical significance of post-operative fever. The cases were followed up for a period of over 3 to 5 years. Temperature charts up to 6 th postoperative day and all investigations were reviewed to determine the cause of fever. Results: Post operative fever was recorded after 82 procedures (44.6%. The average maximum temperature occurred on post-operative day 1 (98.9 o F. Only 2 TKR got infected. Incidence of fever was higher in TKR as compared to THR. Conclusion: Post-operative fever is common and probably inflammatory. It is not an important predictive factor of joint infection. Work up for joint infection is not indicated unless other corroborative features are present. Aspiration of painful joint is a highly accurate for identifying an infection.

  19. The femoral sulcus in total knee arthroplasty.

    Lingaraj, Krishna; Bartlett, John


    The position of the femoral sulcus relative to the midline of the distal femoral resection in total knee arthroplasty (TKA) was studied to determine if centralized placement of the femoral component on the distal femur was justified in terms of aligning the prosthetic sulcus with the native femoral sulcus. The location of the femoral sulcus was studied in 112 consecutive patients undergoing TKA. The mean sulcus position was 0.7 mm lateral to the midline of the distal femoral resection (SD 1.4, 95% CI, 0.5-1.0 mm). However, the variation in sulcus positions ranged from 4 mm medial to 4 mm lateral to the midline. The mean sulcus position in valgus knees was 1.0 mm lateral to the midline (SD 1.8), and that in varus knees was 0.7 mm lateral to the midline (SD 1.2) (P = 0.501). It appears prudent to centre the femoral component on the native sulcus rather than the midline of the distal femoral resection, so as to ensure accurate alignment of the prosthetic sulcus with the native sulcus and to encourage normal patella tracking.

  20. Emerging technologies in arthroplasty: additive manufacturing.

    Banerjee, Samik; Kulesha, Gene; Kester, Mark; Mont, Michael A


    Additive manufacturing is an industrial technology whereby three-dimensional visual computer models are fabricated into physical components by selectively curing, depositing, or consolidating various materials in consecutive layers. Although initially developed for production of simulated models, the technology has undergone vast improvements and is currently increasingly being used for the production of end-use components in various aerospace, automotive, and biomedical specialties. The ability of this technology to be used for the manufacture of solid-mesh-foam monolithic and coated components of complex geometries previously considered unmanufacturable has attracted the attention of implant manufacturers, bioengineers, and orthopedic surgeons. Currently, there is a paucity of reports describing this fabrication method in the orthopedic literature. Therefore, we aimed to briefly describe this technology, some of the applications in other orthopedic subspecialties, its present use in hip and knee arthroplasty, and concerns with the present form of the technology. As there are few reports of clinical trials presently available, the true benefits of this technology can only be realized when studies evaluating the clinical and radiographic outcomes of cementless implants manufactured with additive manufacturing report durable fixation, less stress shielding, and better implant survivorship. Nevertheless, the authors believe that this technology holds great promise and may potentially change the conventional methods of casting, machining, and tooling for implant manufacturing in the future.

  1. Total Knee Arthroplasty in the Combined Contracture

    O.J. Voskresensky


    Full Text Available We have offered modified access to a knee to work out a method for restoration of extensive apparatus of the knee. 91 patients with degenerative damages of the knee were under out su-pervision. All patients were differentiated in groups according to the form of access and pa-thology of the knee. At all stages of studying the following method of investigation were made: goniometry — for estimation of the knee functional condition; electroneiromyography — for reveling deficiency of muscular activity and determination of its kind. Patient's satisfac-tion by operation was defined by means of WOMAC scale subjective indexes. The received digital material was subjected to statistical processing. Thus, it has been proved that applica-tion of the modified access to a knee offered by us in total knee arthroplasty in patients with combined contracture in comparison with traditionally applied technologies of extensive ap-paratus releasing allows in short terms to restore the volume and force of movements in a knee that reduces time of rehabilitation and improves quality of patient's life

  2. Continuous cold therapy in total knee arthroplasty.

    Leutz, D W; Harris, H


    This article describes a retrospective study that assessed 52 consecutive patients who underwent total knee arthroplasty (TKA) between January 1, 1992 and September 15, 1992. Thirty-three patients underwent TKA and received cold therapy pads placed over a thin dressing in the operating room. Nineteen patients underwent TKA using an identical operative and postoperative procedure, but did not receive continuous cold therapy. Continuous cold therapy consisted of two sterile plastic pads connnected by rubber hoses containing cool water from an electric main unit that maintained a constant temperature of 42 degrees F for the immediate postoperative period. Cold therapy pads were used an average of 3 days and removed with the first dressing change. Patients who had continuous cold therapy averaged a 200 cc decrease in postoperative blood loss. There was no significant difference in the amount of narcotic use, transfusion requirements, or hospital stay between the two groups. Postoperative swelling and range of motion were not consistently recorded. Twenty-eight other variables also examined not significant. Based on these results, we cannot recommend continuous cold therapy or justify the extra expense for all patients who undergo TKA.

  3. Can technology improve alignment during knee arthroplasty.

    Thienpont, Emmanuel; Fennema, Peter; Price, Andrew


    Component malalignment remains a concern in total knee arthroplasty (TKA); therefore, a series of technologies have been developed to improve alignment. The authors conducted a systematic review to compare computer-assisted navigation with conventional instrumentation, and assess the current evidence for patient-matched instrumentation and robot-assisted implantation. An extensive search of the PubMed database for relevant meta-analyses, systematic reviews and original articles was performed, with each study scrutinised by two reviewers. Data on study characteristics and outcomes were extracted from each study and compared. In total 30 studies were included: 10 meta-analyses comparing computer-assisted navigation and conventional instrumentation, 13 studies examining patient-matched instrumentation, and seven investigating robot-assisted implantation. Computer-assisted navigation showed significant and reproducible improvements in mechanical alignment over conventional instrumentation. Patient-matched instrumentation appeared to achieve a high degree of mechanical alignment, although the majority of studies were of poor quality. The data for robot-assisted surgery was less indicative. Computer-assisted navigation improves alignment during TKA over conventional instrumentation. For patient-matched instrumentation and robot-assisted implantation, alignment benefits have not been reliably demonstrated. For all three technologies, clinical benefits cannot currently be assumed, and further studies are required. Although current technologies to improve alignment during TKA appear to result in intra-operative benefits, their clinical impact remains unclear, and surgeons should take this into account when considering their adoption.


    Rahbek, Martin Amadeus; Nielsen, Rasmus Oestergaard


    BACKGROUND: Disc golf is rapidly increasing in popularity and more than two million people are estimated to regularly participate in disc golf activities. Despite this popularity, the epidemiology of injuries in disc golf remains under reported. PURPOSE: The purpose of the present study was to in...

  5. Morning glory disc anomaly with Chiari type I malformation.

    Arlow, Tim; Arepalli, Sruthi; Flanders, Adam E; Shields, Carol L


    Morning glory disc anomaly is a rare optic nerve dysplasia associated with various neovascular abnormalities. Due to these associations, children with morning glory disc anomaly have brain imaging and angiography to detect other congenital defects. The authors report the case of an infant with morning glory disc anomaly and coexisting Chiari type I malformation.

  6. Review of gas and dust in debris discs

    Kral, Q.


    This proceeding summarises a talk given on the state-of-the-art of debris disc modelling. We first review the basics of debris disc physics, which is followed by a short overview of the state-of-the-art in terms of modelling dust and gas in debris disc systems.

  7. Review of gas and dust in debris discs

    Kral, Quentin


    This proceeding summarises a talk given on the state-of-the-art of debris disc modelling. We first review the basics of debris disc physics, which is followed by a short overview of the state-of-the-art in terms of modelling dust and gas in debris disc systems.

  8. A method for quantitative measurement of lumbar intervertebral disc structures

    Tunset, Andreas; Kjær, Per; Samir Chreiteh, Shadi


    There is a shortage of agreement studies relevant for measuring changes over time in lumbar intervertebral disc structures. The objectives of this study were: 1) to develop a method for measurement of intervertebral disc height, anterior and posterior disc material and dural sac diameter using MRI...

  9. Review of gas and dust in debris discs

    Kral, Quentin


    This proceeding summarises a talk given on the state-of-the-art of debris disc modelling. We first review the basics of debris disc physics, which is followed by a short overview of the state-of-the-art in terms of modelling dust and gas in debris disc systems.

  10. MOND predictions of 'halo' phenomenology in disc galaxies

    Milgrom, M; Sanders, RH


    We examine two corollaries of MOND pertaining to properties of the equivalent dark matter halo. MOND predicts for pure exponential discs a tight relation involving the halo and disc scalelengths and the mean acceleration in the disc, which we find to test favourably against the Verheijen sample of

  11. Demographics of Transition Discs in Ophiuchus and Taurus

    Najita, Joan R; Muzerolle, James


    Transition disc systems are young stars that appear to be on the verge of dispersing their protoplanetary discs. We explore the nature of these systems by comparing the stellar accretion rates and disc masses of transition discs and normal T Tauri stars in Taurus and Ophiuchus. After controlling for the known dependencies of stellar accretion rate and disc mass and on age, stellar accretion rate on stellar mass, and disc mass on the presence of stellar or sub-stellar companions, we find that the normal T Tauri stars show a trend of stellar accretion rate increasing with disc mass. The transition discs tend to have higher average disc masses than normal T Tauri stars as well as lower accretion rates than normal T Tauri stars of the same disc mass. These results are most consistent with the interpretation that the transition discs have formed objects massive enough to alter the accretion flow, i.e., single or multiple giant planets. Several Ophiuchus T Tauri stars that are not known transition disc systems also...

  12. Prognosis of intervertebral disc loss from diagnosis of degenerative disc disease

    Li, S.; Lin, A.; Tay, K.; Romano, W.; Osman, Said


    Degenerative Disc Disease (DDD) is one of the most common causes of low back pain, and is a major factor in limiting the quality of life of an individual usually as they enter older stages of life, the disc degeneration reduces the shock absorption available which in turn causes pain. Disc loss is one of the central processes in the pathogenesis of DDD. In this study, we investigated whether the image texture features quantified from magnetic resonance imaging (MRI) could be appropriate markers for diagnosis of DDD and prognosis of inter-vertebral disc loss. The main objective is to use simple image based biomarkers to perform prognosis of spinal diseases using non-invasive procedures. Our results from 65 subjects proved the higher success rates of the combination marker compared to the individual markers and in the future, we will extend the study to other spine regions to allow prognosis and diagnosis of DDD for a wider region.


    徐磊; 顾冬红; 等


    Scanning tunneling microscope(STM) is used to investigate the optical dise.The areas with and without data stampers are all observedcarefully.Three-dimensional images of the disc surface clearly demonstrate the period.depth of the grooves and the shape of data stampers.Some phenomena of STM imaging are also discussed.

  14. Low back pain and degenerative disc disease

    Jandrić Slavica


    Full Text Available Introduction. Various clinical conditions can cause low back pain, and in most cases it is of a degenerative origin. Degenerative disc disease is a common condition which affects young to middle-aged men and women equally. Changes in the mechanical properties of the disc lead to degenerative arthritis in the intervertebral joints, osteophytes, and narrowing the intervertebral foramen or the spinal canal. Pathophysiology. Degenerative cascade, described by Kirkaldy-Willis, is the widely accepted pathophysiologic model describing the degenerative process as it affects the lumbar spine in 3 phases. Diagnosis. There are two forms of low back pain secondary to degenerative disc disease: a lumbalgia and b lumbar radiculopathy. Limitation of movement, problems with balance, pain, loss of reflexes in the extremities, muscle weakness, loss of sensation or other signs of neurological damage can be found on physical examination. For accurate diagnosis, it is often necessary to combine clinical examination and sophisticated technology. Treatment. Coservative treatment consists of rest, physical therapy, pharmacological therapy and injection therapy. Physical rehabilitation with active patient participation is a key approach to treatment of patients with discogenic pain. Physical therapy, occupational therapy and kinesitherapy are important for improving muscle strength, endurance, and flexibility. Disc surgery is performed if surgical intervention is required. .

  15. Cometary ices in forming protoplanetary disc midplanes

    Drozdovskaya, Maria N; van Dishoeck, Ewine F; Furuya, Kenji; Marboeuf, Ulysse; Thiabaud, Amaury; Harsono, Daniel; Visser, Ruud


    Low-mass protostars are the extrasolar analogues of the natal Solar System. Sophisticated physicochemical models are used to simulate the formation of two protoplanetary discs from the initial prestellar phase, one dominated by viscous spreading and the other by pure infall. The results show that the volatile prestellar fingerprint is modified by the chemistry en route into the disc. This holds relatively independent of initial abundances and chemical parameters: physical conditions are more important. The amount of CO2 increases via the grain-surface reaction of OH with CO, which is enhanced by photodissociation of H2O ice. Complex organic molecules are produced during transport through the envelope at the expense of CH3OH ice. Their abundances can be comparable to that of methanol ice (few % of water ice) at large disc radii (R > 30 AU). Current Class II disc models may be underestimating the complex organic content. Planet population synthesis models may underestimate the amount of CO2 and overestimate CH3...

  16. Front view of the innermost endcap disc.

    Maximilien Brice


    This ~750 tonne disc is covered with muon chambers (copper-coloured) with the hadron calorimeter and Preshower support cone at the centre. The image was taken through one of the barrel rings; some barrel muon chambers can be seen at the edges of the picture. Bigger files available (39 Mpx)

  17. Front view of the innermost endcap disc.

    Maximilien Brice


    This ~750 tonne disc is covered with muon chambers (copper-coloured) with the hadron calorimeter and Preshower support cone at the centre. The image was taken through one of the barrel rings; some barrel muon chambers can be seen at the edges of the picture.

  18. Disc degeneration-related clinical phenotypes.

    Battié, Michele C; Lazáry, Aron; Fairbank, Jeremy; Eisenstein, Stephen; Heywood, Chris; Brayda-Bruno, Marco; Varga, Péter Pál; McCall, Iain


    The phenotype, or observable trait of interest, is at the core of studies identifying associated genetic variants and their functional pathways, as well as diagnostics. Yet, despite remarkable technological developments in genotyping and progress in genetic research, relatively little attention has been paid to the equally important issue of phenotype. This is especially true for disc degeneration-related disorders, and the concept of degenerative disc disease, in particular, where there is little consensus or uniformity of definition. Greater attention and rigour are clearly needed in the development of disc degeneration-related clinical phenotypes if we are to see more rapid advancements in knowledge of this area. When selecting phenotypes, a basic decision is whether to focus directly on the complex clinical phenotype (e.g. the clinical syndrome of spinal stenosis), which is ultimately of interest, or an intermediate phenotype (e.g. dural sac cross-sectional area). While both have advantages, it cannot be assumed that associated gene variants will be similarly relevant to both. Among other considerations are factors influencing phenotype identification, comorbidities that are often present, and measurement issues. Genodisc, the European research consortium project on disc-related clinical pathologies has adopted a strategy that will allow for the careful characterisation and examination of both the complex clinical phenotypes of interest and their components.

  19. Global Structure of Magnetorotationally Turbulent Protoplanetary Discs

    Flaig, M; Kley, W; Kissmann, R


    The aim of the present paper is to investigate the spatial structure of a protoplanetary disc whose dynamics is governed by magnetorotational turbulence. We perform a series of local 3D chemo-radiative MHD simulations located at different radii of a disc which is twice as massive as the standard minimum mass solar nebula of Hayashi (1981). The ionisation state of the disc is calculated by including collisional ionisation, stellar X-rays, cosmic rays and the decay of radionuclides as ionisation sources, and by solving a simplified chemical network which includes the effect of the absorption of free charges by {\\mu}m-sized dust grains. In the region where the ionisation is too low to assure good coupling between matter and magnetic fields, a non-turbulent central "dead zone" forms, which ranges approximately from a distance of 2 AU to 4 AU from the central star. The approach taken in the present work allows for the first time to derive the global spatial structure of a protoplanetary disc from a set of physical...

  20. Kinematic structures in galactic disc simulations

    Roca-F� brega, S.; Romero-Gómez, M.; Figueras, F.; Antoja Castelltort, Teresa; Valenzuela, O.; Henney, W.J.; Torres-Peimbert, S.


    N-body and test particle simulations have been used to characterize the stellar streams in the galactic discs of Milky Way type galaxies. Tools such as the second and third order moments of the velocity ellipsoid and clustering methods -EM-WEKA and FoF- allow characterizing these kinematic structure