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Sample records for bioabsorbable screw fixation

  1. Arthroscopic Bioabsorbable Screw Fixation of Unstable Osteochondritis Dissecans in Adolescents: Clinical Results, Magnetic Resonance Imaging, and Second-Look Arthroscopic Findings

    Science.gov (United States)

    Chun, Keun Churl; Kim, Kwang Mee; Jeong, Ki Joon; Lee, Yong Chan; Kim, Jeong Woo

    2016-01-01

    Background This study aimed to evaluate the clinical and radiological outcomes of arthroscopic bioabsorbable screw fixation in osteochondritis dissecans (OCD) in adolescent patients with unstable lesions causing pain. Methods The study included 11 patients (10 males and 1 female) with OCD who underwent arthroscopic bioabsorbable screw fixation between July 2007 and February 2014 and were available for follow-up for more than 12 months. The mean age at diagnosis was 16.3 years (range, 11 to 19 years), and the average follow-up period was 51 months (range, 12 to 91 months). Clinical results were evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS), Lysholm knee score, and International Knee Documentation Committee (IKDC) score measured before surgery and at follow-up. Functional evaluation was made using the Tegner activity scale. Magnetic resonance imaging (MRI) and second-look arthroscopy were performed at the 12-month follow-up. Results Between the preoperative assessment and follow-up, improvements were seen in the KOOS (range, 44.9 to 88.1), Lysholm knee score (range, 32.6 to 82.8), and IKDC score (range, 40.8 to 85.6). The Tegner activity scale also improved from 2.8 to 6.1. Based on postoperative MRI, there were eight Dipaola grade I cases and three grade II cases. No complications due to fixation failure developed in any case. Second-look arthroscopy at 12 months postoperatively revealed that the lesion was covered with cartilage in all cases. Conclusions For unstable OCD lesions causing pain in adolescents, arthroscopic bioabsorbable screw fixation provided favorable outcomes with reduced pain and restoration of movement. Therefore, it should be considered as an effective treatment for OCD. PMID:26929800

  2. Femoral fracture following knee ligament reconstruction surgery due to an unpredictable complication of bioabsorbable screw fixation: a case report and review of literature

    OpenAIRE

    Konan, Sujith; Haddad, Fares Sami

    2009-01-01

    We report an unusual case of femoral fracture from minimal trauma, due to the rapid disappearance of a bioabsorbable interference screw used for reconstruction of the posterolateral corner of the knee. The literature on bone tunnel fractures following knee ligament reconstruction surgery is also reviewed.

  3. Tibial Tunnel Cyst Formation after Anterior Cruciate Ligament Reconstruction Using a Non-Bioabsorbable Interference Screw.

    Science.gov (United States)

    Joshi, Yogesh V; Bhaskar, Deepu; Phaltankar, Padmanabh M; Charalambous, Charalambos P

    2015-12-01

    Tibial cyst formation following the use of bioabsorbable interference screws in anterior cruciate ligament (ACL) reconstruction is well-described; however, cyst formation after the use of metallic interference screws is not well-documented. We describe a case of osteolytic lesion of the proximal tibia presenting to us 20 years after ACL reconstruction using an autologous bone-tendon-bone graft. The original graft fixation technique was interference fixation with a metal screw in the tibial and femoral tunnels. A two-stage revision reconstruction of the ACL was undertaken with curettage and bone grafting of the tibial lesion in the first stage and reconstruction using a four-strand hamstring tendon in the second stage. The patient recovered satisfactorily with complete healing of the cyst and returned to pre-injury level of activities. We have reviewed case reports and case series that describe the aetiology of intra-osseous cyst formation following ACL reconstruction. PMID:26673117

  4. BIOMECHANICAL STUDY OF TRANSCORTICAL OR TRANSTRABECULAR BONE FIXATION OF PATELLAR TENDON GRAFT WITH BIOABSORBABLE PINS IN ACL RECONSTRUCTION IN SHEEP

    Science.gov (United States)

    Albano, Mauro Batista; Borges, Paulo César; Namba, Mario Massatomo; da Silva, João Luiz Vieira; de Assis Pereira Filho, Francisco; Filho, Edmar Stieven; Matias, Jorge Eduardo Fouto

    2015-01-01

    Objective: To determine the initial resistance of fixation using the Rigid Fix® system, and compare it with traditional fixation methods using metal interference screws; and to evaluate the resistance of the fixation with the rigid fix system when the rotational position of the bone block is altered in the interior of the femoral tunnel. Methods: forty ovine knee specimens (stifle joints) were submitted to anterior cruciate ligament reconstruction (ACL) using a bone-tendon-bone graft. In twenty specimens, the Rigid Fix method was used; this group was subdivided into two groups: ten knees the pins transfixed only the spongious area of the bone block, and ten for fixation passing through the layer of cortical bone. In the twenty remaining specimens, the graft was fixed with 9mm metal interference screws. Results: comparison of the RIGIDFIX® method with the metal interference screw fixation method did not show any statistically significant differences in terms of maximum load and rigidity; also, there were no statistically significant differences when the rotational position of the bone block was altered inside the femoral tunnel. For these evaluations, a level of significance of p < 0.017 was considered. Conclusion: fixation of the bone-tendon-bone graft with 2 bioabsorbable pines, regardless of the rotational position inside the femoral tunnel, gave a comparable fixation in terms of initial resistance to the metal interference screw, in this experimental model. PMID:27027081

  5. Interference Screw vs. Suture Anchor Fixation for Open Subpectoral Biceps Tenodesis: Does it Matter?

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    Gobezie Reuben

    2008-09-01

    Full Text Available Abstract Background Bioabsorbable interference screw fixation has superior biomechanical properties compared to suture anchor fixation for biceps tenodesis. However, it is unknown whether fixation technique influences clinical results. Hypothesis We hypothesize that subpectoral interference screw fixation offers relevant clinical advantages over suture anchor fixation for biceps tenodesis. Study Design Case Series. Methods We performed a retrospective review of a consecutive series of 88 patients receiving open subpectoral biceps tenodesis with either interference screw fixation (34 patients or suture anchor fixation (54 patients. Average follow up was 13 months. Outcomes included Visual Analogue Pain Scale (0–10, ASES score, modified Constant score, pain at the tenodesis site, failure of fixation, cosmesis, deformity (popeye and complications. Results There were no failures of fixation in this study. All patients showed significant improvement between their preoperative and postoperative status with regard to pain, ASES score, and abbreviated modified Constant scores. When comparing IF screw versus anchor outcomes, there was no statistical significance difference for VAS (p = 0.4, ASES score (p = 0.2, and modified Constant score (P = 0.09. One patient (3% treated with IF screw complained of persistent bicipital groove tenderness, versus four patients (7% in the SA group (nonsignificant. Conclusion Subpectoral biceps tenodesis reliably relieves pain and improves function. There was no statistically significant difference in the outcomes studied between the two fixation techniques. Residual pain at the site of tenodesis may be an issue when suture anchors are used in the subpectoral location.

  6. Bone resorption around pedicle screws after pedicle screw plate fixation

    International Nuclear Information System (INIS)

    To determine the frequency, level, distribution, onset, and pattern of progression of bone resorption that occurring around pedicle screws after pedicle screw plate fixation. Bone resorption around 902 pedicle screws was analyzed in post-operative, and follow-up radiographs obtained from 156 patients who underwent pedicle screw plate fixation. To determine the resorption degree, categorized arbitrarily as grade 1 (less than 1 mm), grade 2 (1mm or more, but less than 2 mm), or grade 3 (2mm or more), the width of radiolucent zones was measured. In 39 patients in whom resorption was graded 1, 2 or 3, the pattern of progression of 78 screws was evaluated. Resorption occurred around 78 (8.6%) screws in 39 (25%) patients, 26 of whom had more than on lesion. For 99% of screws, there was evidance of resorption within 12 weeks of pedicle screw plate fixation. During follow-up, 61.5% of screws (48/78) remained stable, while 38.5% (30 screws) showed progression to higher grades. The possibility of progression to a higher grade is less when the initial grade is lower. An understanding of the radiographic patterns of bone resorption is useful for monitoring a patient after pedicle screw plate fixation

  7. Bioabsorbable pins for bone fixation in the less invasive innominate osteotomy.

    Science.gov (United States)

    Dawson, Peter H; O'Briain, David E; Connolly, Paul J; McCormack, Damien

    2014-09-01

    For the less invasive innominate osteotomy for the treatment of developmental dysplasia of the hip, we aim to report radiological outcomes, complication rates and reoperation rates for patients whose bone grafts were secured using bioabsorbable pins. A retrospective study of all patients who underwent less invasive innominate osteotomy for persistent or delayed diagnosis developmental dysplasia of the hip over a period of 2 years from 2008 to 2010 was carried out. A total of 59 hips were identified as having had their bone graft secured with two bioabsorbable pins made from copolymers of L-lactic acid, D-lactic acid and trimethylene carbonate. The average angular correction of the acetabular index in the bioabsorbable group at late follow-up was 16.48° (P<0.0001). Seven percent of patients from the bioabsorbable pin group went on to require reoperation for persistent dysplasia. No patient required reoperation due to implant failure. There was no incidence of postoperative wound infection or other complication requiring medical or surgical intervention. These results demonstrate that the use of bioabsorbable pins to secure the bone graft is as effective and safe as metal fixation. PMID:24911940

  8. Transarticular screw fixation using neuronavigation: Technique

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    Dwarakanath Srinivas

    2007-01-01

    Full Text Available Background: Transarticular screw placement needs highly accurate imaging. We assess the efficacy and accuracy of C1-C2 transarticular screw fixation using neuronavigation and also cast a technical note on the procedure. Materials and Methods: This study included a total of nine patients who underwent transarticular screw fixation using the neuronavigation system. A total of 15 screws were placed. All patients underwent postoperative CT scan with 3-Dimensional (3-D reconstruction to check for the accuracy of implantation. Results: One patient had encroachment of the transverse foramen but there was no vertebral artery injury. There were no clinical complications or adverse sequelae. Conclusion: Neuronavigation is extremely helpful in C1-C2 transarticular screw fixation and gives excellent accuracy.

  9. 21 CFR 872.4880 - Intraosseous fixation screw or wire.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intraosseous fixation screw or wire. 872.4880... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4880 Intraosseous fixation screw or wire. (a) Identification. An intraosseous fixation screw or wire is a metal device intended to be...

  10. Scaphoid Fracture Fixation with an Acutrak(®) Screw.

    Science.gov (United States)

    Loving, Vilert A; Richardson, Michael L

    2006-01-01

    We report a case of fixation of a scaphoid fracture using an Acutrak(®) screw. This screw is cannulated and headless, which allows it to be implanted below the surface of the bone. It uses the same concept of variable thread pitch as the Herbert screw, but unlike the Herbert screw, is fully threaded, with continuously varying pitch along its length. This variable pitch creates constant compression across a fracture as the screw is advanced, and gives the screw its unique appearance. This feature may improve internal holding power, as well as allow a fracture or osteotomy site to lie anywhere along the length of the screw. PMID:27298683

  11. Bioabsorbable fish scale for the internal fixation of fracture: a preliminary study.

    Science.gov (United States)

    Chou, Cheng-Hung; Chen, Yong-Guei; Lin, Chien-Chen; Lin, Shang-Ming; Yang, Kai-Chiang; Chang, Shih-Hsin

    2014-09-01

    Fish scales, which consist of type I collagen and hydroxyapatite (HA), were used to fabricate a bioabsorbable bone pin in this study. Fresh fish scales were decellularized and characterized to provide higher biocompatibility. The mechanical properties of fish scales were tested, and the microstructure of an acellular fish scale was examined. The growth curve of a myoblastic cell line (C2C12), which was cultured on the acellular fish scales, implied biocompatibility in vitro, and the morphology of the cells cultured on the scales was observed using scanning electron microscopy (SEM). A bone pin made of decellularized fish scales was used for the internal fixation of femur fractures in New Zealand rabbits. Periodic X-ray evaluations were obtained, and histologic examinations were performed postoperatively. The present results show good cell growth on decellularized fish scales, implying great biocompatibility in vitro. Using SEM, the cell morphology revealed great adhesion on a native, layered collagen structure. The Young's modulus was 332 ± 50.4 MPa and the tensile strength was 34.4 ± 6.9 MPa for the decellularized fish scales. Animal studies revealed that a fish-scale-derived bone pin improved the healing of bone fractures and degraded with time. After an 8-week implantation, the bone pin integrated with the adjacent tissue, and new extracellular matrix was synthesized around the implant. Our results proved that fish-scale-derived bone pins are a promising implant material for bone healing and clinical applications. PMID:25211643

  12. Use of polymethylmethacrylate to enhance screw fixation in bone.

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    Cameron, H U; Jacob, R; Macnab, I; Pilliar, R M

    1975-07-01

    Pull-out testing of screws inserted into cement and bone under various conditions showed that the cement-screw complex was significantly stronger when the screw was placed in soft cement and the cement was allowed to polymerize without further manipulation. When screw fixation in osteoporotic bone was reinforced with cement, the bone was the weakest component in the system. Fixation under these conditions should be enhanced by increasing the area of contact between the cement and bone. By cooling the cement to prolong its working time, it could be injected with a syringe in such a way that maximum endosteal and periosteal contact was provided. PMID:1150708

  13. Outcome comparison of Lisfranc injuries treated through dorsal plate fixation versus screw fixation

    OpenAIRE

    Hu, Sun-jun; Chang, Shi-Min; Li, Xiao-Hua; Yu, Guang-rong

    2014-01-01

    OBJECTIVE: The objective of this prospective study was to test whether the treatment of Lisfranc injuries with open reduction and dorsal plate fixation would have the same or better functional outcomes as treatment with standard trans-articular screw fixation. METHODS: Sixty patients with primarily isolated Lisfranc joint injury were treated by open reduction and dorsal plate fixation or standard screw fixation. The patients were followed on average for 31 months. Evaluation was performed wit...

  14. Biomechanical Analysis of Pedicle Screw Fixation for Thoracolumbar Burst Fractures.

    Science.gov (United States)

    McDonnell, Matthew; Shah, Kalpit N; Paller, David J; Thakur, Nikhil A; Koruprolu, Sarath; Palumbo, Mark A; Daniels, Alan H

    2016-05-01

    Treatment of unstable thoracolumbar burst fractures remains controversial. Long-segment pedicle screw constructs may be stiffer and impart greater forces on adjacent segments compared with short-segment constructs, which may affect clinical performance and long-term out come. The purpose of this study was to biomechanically evaluate long-segment posterior pedicle screw fixation (LSPF) vs short-segment posterior pedicle screw fixation (SSPF) for unstable burst fractures. Six unembalmed human thoracolumbar spine specimens (T10-L4) were used. Following intact testing, a simulated L1 burst fracture was created and sequentially stabilized using 5.5-mm titanium polyaxial pedicle screws and rods for 4 different constructs: SSPF (1 level above and below), SSPF+L1 (pedicle screw at fractured level), LSPF (2 levels above and below), and LSPF+L1 (pedicle screw at fractured level). Each fixation construct was tested in flexion-extension, lateral bending, and axial rotation; range of motion was also recorded. Two-way repeated-measures analysis of variance was performed to identify differences between treatment groups and functional noninstrumented spine. Short-segment posterior pedicle screw fixation did not achieve stability seen in an intact spine (P.1). Long-segment posterior pedicle screw fixation constructs were not associated with increased adjacent segment motion. Al though the sample size of 6 specimens was small, this study may help guide clinical decisions regarding burst fracture stabilization. [Orthopedics. 2016; 39(3):e514-e518.]. PMID:27135451

  15. Ureteral injury after posterior lumbar discectomy with interbody screw fixation

    OpenAIRE

    Pillai, Sunil Bhaskara; Hegde, Padmaraj; Venkatesh, Giridhar; Iyyan, Bhalaguru

    2013-01-01

    We report a case of iatrogenic ureteral injury secondary to L5 laminectomy and microdiscectomy with L5–S1 bone graft with posterior lumbar interbodyfusion using presacral cancellous screw fixation, managed by initial ureteral stent placement and subsequent Boari bladder flap repair. A 33-year-old woman underwent L5 laminectomy and microdiscectomy with L5–S1 bone graft with posterior lumbar interbody fusion using presacral cancellous screw fixation. On postoperative day 10, she developed lower...

  16. Sacroiliac screw fixation: A mini review of surgical technique

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    Hernando Raphael Alvis-Miranda

    2014-01-01

    Full Text Available The sacral percutaneous fixation has many advantages but can be associated with a significant exposure to X-ray radiation. Currently, sacroiliac screw fixation represents the only minimally invasive technique to stabilize the posterior pelvic ring. It is a technique that should be used by experienced surgeons. We present a practical review of important aspects of this technique.

  17. Fracture fixation with two locking screws versus three non-locking screws

    OpenAIRE

    Grawe, B.; Le Van, T.; Williamson, S.; Archdeacon, A.; Zardiackas, L

    2012-01-01

    Objectives We aimed to further evaluate the biomechanical characteristics of two locking screws versus three standard bicortical screws in synthetic models of normal and osteoporotic bone. Methods Synthetic tubular bone models representing normal bone density and osteoporotic bone density were used. Artificial fracture gaps of 1 cm were created in each specimen before fixation with one of two constructs: 1) two locking screws using a five-hole locking compression plate (LCP) plate; or 2) thre...

  18. A biomechanical comparison between cortical bone trajectory fixation and pedicle screw fixation

    OpenAIRE

    Oshino, Hiroki; Sakakibara, Toshihiko; Inaba, Tadashi; Yoshikawa, Takamasa; Kato, Takaya; Kasai, Yuichi

    2015-01-01

    Purpose There have been several reports on the pullout strength of cortical bone trajectory (CBT) screws, but only one study has reviewed the stability of functional spine units using the CBT method. The purpose of this study was to compare vertebral stability after CBT fixation with that after pedicle screw (PS) fixation. Methods In this study, 20 lumbar spine (L5–6) specimens were assigned to two groups: the CBT model group that underwent CBT screw fixation (n = 10) and the PS model group t...

  19. Inadvertent Screw Stripping During Ankle Fracture Fixation in Elderly Bone

    OpenAIRE

    Dinah, A. Feroz; Mears, Simon C.; Knight, Trevor A.; Soin, Sandeep P.; Campbell, John T.; Belkoff, Stephen M.

    2011-01-01

    Poor screw purchase because of osteoporosis presents difficulties in ankle fracture fixation. The aim of our study was to determine if cortical thickness, unicortical versus bicortical purchase, and bone mineral density are predictors of inadvertent screw stripping and overtightening. Ten paired cadaver ankles (average donor age, 81.7 years; range, 50-97 years) were used for the study. Computed tomography scanning with phantoms of known density was used to determine the bone density along the...

  20. Transverse lag screw fixation in midline mandibulotomy. A case series.

    Science.gov (United States)

    Serletti, J M; Pacella, S J; Coniglio, J U; Norante, J D

    2000-03-01

    Vertical midline mandibulotomy has provided a relatively simple and efficient means of obtaining access to intraoral tumors that are too large or too posterior to be removed transorally. Midline mandibulotomy has had the advantage of nerve and muscle preservation and places the osteotomy outside the typical field of radiotherapy, in contrast to lateral and paramedian osteotomies. Plate and screw fixation has been the usual means of osteosynthesis for these mandibulotomies; however, plate contouring over the symphyseal surface has been a time-consuming process. Unless the plate was contoured exactly, mandibular malalignment and malocclusion in dentulous patients has occurred. Use of parallel transverse lag screws has become a popular method of osteosynthesis for parasymphyseal fractures, and we have extended their use for mandibulotomy fixation. This paper reports our clinical experience with transverse lag screw fixation of midline mandibulotomies in 9 patients from 1994 to 1997. There were 7 men and 2 women with a mean age of 56 (range 35 to 71 years). The pathological diagnosis in all patients was squamous cell carcinoma; 8 cases were primary, and 1 patient presented with recurrent tumor. No tumors involved the mandibular periosteum. One patient had had previous radiotherapy, and 3 patients underwent postoperative radiotherapy. The mean follow-up has been 17 months (range 9 to 27). There was 1 minor complication and 1 major complication related to our technique. The major complication was a delayed nonunion of the mandibulotomy. This occurred because the 2 parallel screws were placed too close to one another, and this placement resulted in a delayed sagittal fracture of the anterior cortex and subsequent nonunion. Transverse lag screw fixation has not affected occlusion in our dentulous patients. Speech and diet were normal in the majority of our patients. Transverse lag screw fixation of the midline mandibulotomy has been a relatively safe, rapid, and reliable

  1. Augmentation of Pedicle Screw Fixation with Calcium Phosphate Cement

    Institute of Scientific and Technical Information of China (English)

    YANG Shu-hua; FU De-hao; LI Jin; XU Wei-hua; YANG Cao; YE Zhe-wei; ZUO Xiao-yan

    2004-01-01

    To determine whether a biodegradable calcium phosphate cement(CPC) provides significant augmentation of pedicle screw fixation or not,an in vitro biomechanical study was carried out to evaluate the biomechanical effect of CPC in the restoration and augmentation of pedicle screw fixation.Axial pullout test and cyclic bending resistance test were employed in the experiment,and polymethylmethacrylate (PMMA) was chosen as control.The results demonstrate that the pullout strengths following CPC restoration and augmentation are 74% greater on an average than those of the control group,but less than those of PMMA restoration group and augmentation group respectively (increased by 126% versus control).In cyclic bending resistance test,the CPC augmented screws are found to withstand a greater number of cycles or greater loading with less displacement before loosening,but the augmentation effect of PMMA is greater than that of CPC.

  2. Posterior atlantoaxial transpedicle screw fixation for traumatic atlatoaxial instability

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    Zheng-lei WANG

    2015-10-01

    Full Text Available Objective To explore the clinical efficacy of posterior atlantoaxial pedicle screw fixation for traumatic atlantoaxial instability. Methods From September 2009 to March 2013, 17 patients with atlantoaxial instability received posterior atlantoaxial pedicle screw fixation. There were 12 males and 5 females, with a mean age of 42 years old (ranged from 19 to 63 years old. Transpedicle screw fixation was employed in 8 patients with atlantoaxial fracture and dislocation, in 2 with traumatic disruption of transverse atlantal ligament, and in 7 with odontoid fracture. The Japanese Orthopaedic Association (JOA score before operation was from 5 to 14, with a mean of 11.2. Preoperative CT, MRI and radiographs, as well as intraoperative screw placement and bone graft were administered in all the patients. Results In all the patients, complete reduction was achieved without injury to the vertebral artery, spinal cord or never root, and they started to be ambulatory on the first day after the operation. The patients were followed up for 6-36 months (mean 21 months, and clinical symptoms were seen to be improved significantly. Imaging reexamination 6 months after the surgery showed satisfactory healing of implanted bone and position of all the screws without loosening of the implant. The mean JOA scores was 15.5(11.0-17.0 twelve months after the operation. Conclusion Atlantoaxial pedicle screw fixation for traumatic atlantoaxial instability is safe and reliable with a favorable clinical result. DOI: 10.11855/j.issn.0577-7402.2015.09.14

  3. Biomechanical analysis of tibia – double threaded screw fixation

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    W. Walke

    2008-03-01

    Full Text Available Purpose: The aim of the work was determination of biomechanical characteristics of a tibia – double threaded screw system with the use of finite element method.Design/methodology/approach: Geometrical model of the tibia was worked out on the basis of data from computer tomography of real bone. Geometrical model of the double threaded screw was prepared in ANSYS v. 11. Meshing was realized with the use of SOLID95 elements, applied in analyses of volumes. The model was loaded with forces in the range F = 100-2000 N.Findings: Initial biomechanical analysis, carried out with the use of finite element method, showed usefulness of the analyzed form of the double threaded screw made of Ti6Al4V alloy in fractured tibia treatment.Research limitations/implications: Due to applied simplifications of the tibia – double threaded screw fixation model, the analysis results should be experimentally verified in laboratory conditions.Originality/value: The obtained biomechanical characteristics of the tibia – double threaded screw system (u = f(F, σmax = f(F are the basis for selection of degree of strain hardening of the applied metallic biomaterial and optimization of geometrical features of the analyzed form of implant. Appropriate selection of mechanical properties and geometrical features of the implant is the main factor determining a stability of the fixation.

  4. Transpedicular screw fixation in the thoracic and lumbar spine with a novel cannulated polyaxial screw system

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    Lutz Weise

    2008-10-01

    Full Text Available Lutz Weise, Olaf Suess, Thomas Picht, Theodoros KombosNeurochirurgische Klinik, Charité – Universitätsmedizin Berlin, Berlin, GermanyObjective: Transpedicular screws are commonly and successfully used for posterior fixation in spinal instability, but their insertion remains challenging. Even using navigation techniques, there is a misplacement rate of up to 11%. The aim of this study was to assess the accuracy of a novel pedicle screw system.Methods: Thoracic and lumbar fusions were performed on 67 consecutive patients for tumor, trauma, degenerative disease or infection. A total of 326 pedicular screws were placed using a novel wire-guided, cannulated, polyaxial screw system (XIA Precision®, Stryker. The accuracy of placement was assessed post operatively by CT scan, and the patients were followed-up clinically for a mean of 16 months.Results: The total medio-caudal pedicle wall perforation rate was 9.2% (30/326. In 19 of these 30 cases a cortical breakthrough of less than 2 mm occurred. The misplacement rate (defined as a perforation of 2 mm or more was 3.37% (11/326. Three of these 11 screws needed surgical revision due to neurological symptoms or CSF leakage. There have been no screw breakages or dislocations over the follow up-period.Conclusion: We conclude that the use of this cannulated screw system for the placement of pedicle screws in the thoracic and lumbar spine is accurate and safe. The advantages of this technique include easy handling without a time-consuming set up. Considering the incidence of long-term screw breakage, further investigation with a longer follow-up period is necessary.Keywords: spinal instrumentation, pedicle screws, misplacement, pedicle wall perforation

  5. Experimental and Numerical Modeling of Screws Used for Rigid Internal Fixation of Mandibular Fractures

    OpenAIRE

    Naresh Chaudhary; Lovald, Scott T.; Jon Wagner; Tariq Khraishi; Bret Baack

    2008-01-01

    Experimental and numerical methods are used to explore the stresses generated around bone screws used in rigid internal fixation of mandibular fractures. These results are intended to aid in decisions concerning both the design and the use of these bone screws. A finite element (FE) model of a human mandible is created with a fixated fracture in the parasymphyseal region. The mandibular model is anatomically loaded, and the forces exerted by the fixation plate onto the simplified screws are o...

  6. Biomechanical Evaluation of Plate Versus Lag Screw Only Fixation of Distal Fibula Fractures.

    Science.gov (United States)

    Misaghi, Amirhossein; Doan, Josh; Bastrom, Tracey; Pennock, Andrew T

    2015-01-01

    Traditional fixation of unstable Orthopaedic Trauma Association type B/C ankle fractures consists of a lag screw and a lateral or posterolateral neutralization plate. Several studies have demonstrated the clinical success of lag screw only fixation; however, to date no biomechanical comparison of the different constructs has been performed. The purpose of the present study was to evaluate the biomechanical strength of these different constructs. Osteotomies were created in 40 Sawbones(®) distal fibulas and reduced using 1 bicortical 3.5-mm stainless steel lag screw, 2 bicortical 3.5-mm lag screws, 3 bicortical 3.5-mm lag screws, or a single 3.5-mm lag screw coupled with a stainless steel neutralization plate with 3 proximal cortical and 3 distal cancellous screws. The constructs were tested to determine the stiffness in lateral bending and rotation and failure torque. No significant differences in lateral bending or rotational stiffness were detected between the osteotomies fixed with 3 lag screws and a plate. Constructs fixed with 1 lag screw were weaker for both lateral bending and rotational stiffness. Osteotomies fixed with 2 lag screws were weaker in lateral bending only. No significant differences were found in the failure torque. Compared with lag screw only fixation, plate fixation requires larger incisions and increased costs and is more likely to require follow-up surgery. Despite the published clinical success of treating simple Orthopaedic Trauma Association B/C fractures with lag screw only fixation, many surgeons still have concerns about stability. For noncomminuted, long oblique distal fibula fractures, lag screw only fixation techniques offer construct stiffness similar to that of traditional plate and lag screw fixation. PMID:25990534

  7. Design of three-dimensional visualization based on the posterior lumbar pedicle screw fixation

    OpenAIRE

    Xu, Kai; Chen, Chun; Shan-dong HUANG; Zhang, Ying; Qing-shui YIN

    2011-01-01

    Objective To establish a three-dimensional visualization model of posterior lumbar pedicle screw fixation.Methods A patient with lumbar intervertebral disc hernia and another patient with compression fracture of lumbar vertebra were involved in the present study.Both patients underwent multi-slice spiral CT scan before and after lumbar pedicle screw fixation.The degree of preoperative vertebral compression,vertebral morphology before and after surgery,postoperative pedicle screw position,and ...

  8. Unilateral Pedicle Screw Fixation with Bone Graft vs. Bilateral Pedicle Screw Fixation with Bone Graft or Cage: A Comparative Study.

    Science.gov (United States)

    Yang, Si-Dong; Chen, Qian; Ding, Wen-Yuan; Zhao, Jian-Qiang; Zhang, Ying-Ze; Shen, Yong; Yang, Da-Long

    2016-01-01

    BACKGROUND The aim of this study was to explore the clinical efficacy of unilateral pedicle screw fixation with bone graft (UPSFB) in treating single-segment lumbar degenerative diseases (LDD), as compared to bilateral pedicle screw fixation with bone graft (BPSFB) or with cage (BPSFC). MATERIAL AND METHODS Medical records were retrospectively collected between 01/2010 and 02/2015 in Longyao County Hospital. According to surgical methods used, all patients were divided into 3 groups: UPSFB group, BPSFB group, and BPSFC group. Clinical outcomes were evaluated by blood loss, blood transfusion, duration of operation, hospital stay, postoperative complications, interbody fusion rate, reoperation rate, medical expenses, patient satisfaction survey, and JOA score. RESULTS Ninety-five patients were included and underwent 2.5-year follow-up, with 7 patients lost to regular follow-up. As compared to the BPSFB group and BPSFC group, the UPSFB group had less blood loss and less blood transfusion, as well as shorter hospital stay (pfusion rate, reoperation rate, JOA score, and patient satisfaction (all p>0.05). CONCLUSIONS As compared to BPSFB and BPSFC, UPSFB has the same reliability and effectiveness in treating single-segment LDD with unilateral radicular symptoms in a single lower extremity, with the additional advantage being less expensive. PMID:26988532

  9. Unilateral Pedicle Screw Fixation with Bone Graft vs. Bilateral Pedicle Screw Fixation with Bone Graft or Cage: A Comparative Study

    Science.gov (United States)

    Yang, Si-Dong; Chen, Qian; Ding, Wen-Yuan; Zhao, Jian-Qiang; Zhang, Ying-Ze; Shen, Yong; Yang, Da-Long

    2016-01-01

    Background The aim of this study was to explore the clinical efficacy of unilateral pedicle screw fixation with bone graft (UPSFB) in treating single-segment lumbar degenerative diseases (LDD), as compared to bilateral pedicle screw fixation with bone graft (BPSFB) or with cage (BPSFC). Material/Methods Medical records were retrospectively collected between 01/2010 and 02/2015 in Longyao County Hospital. According to surgical methods used, all patients were divided into 3 groups: UPSFB group, BPSFB group, and BPSFC group. Clinical outcomes were evaluated by blood loss, blood transfusion, duration of operation, hospital stay, postoperative complications, interbody fusion rate, reoperation rate, medical expenses, patient satisfaction survey, and JOA score. Results Ninety-five patients were included and underwent 2.5-year follow-up, with 7 patients lost to regular follow-up. As compared to the BPSFB group and BPSFC group, the UPSFB group had less blood loss and less blood transfusion, as well as shorter hospital stay (p0.05). Conclusions As compared to BPSFB and BPSFC, UPSFB has the same reliability and effectiveness in treating single-segment LDD with unilateral radicular symptoms in a single lower extremity, with the additional advantage being less expensive. PMID:26988532

  10. Finite element analysis of osteosynthesis screw fixation in the bone stock: an appropriate method for automatic screw modelling.

    Science.gov (United States)

    Wieding, Jan; Souffrant, Robert; Fritsche, Andreas; Mittelmeier, Wolfram; Bader, Rainer

    2012-01-01

    The use of finite element analysis (FEA) has grown to a more and more important method in the field of biomedical engineering and biomechanics. Although increased computational performance allows new ways to generate more complex biomechanical models, in the area of orthopaedic surgery, solid modelling of screws and drill holes represent a limitation of their use for individual cases and an increase of computational costs. To cope with these requirements, different methods for numerical screw modelling have therefore been investigated to improve its application diversity. Exemplarily, fixation was performed for stabilization of a large segmental femoral bone defect by an osteosynthesis plate. Three different numerical modelling techniques for implant fixation were used in this study, i.e. without screw modelling, screws as solid elements as well as screws as structural elements. The latter one offers the possibility to implement automatically generated screws with variable geometry on arbitrary FE models. Structural screws were parametrically generated by a Python script for the automatic generation in the FE-software Abaqus/CAE on both a tetrahedral and a hexahedral meshed femur. Accuracy of the FE models was confirmed by experimental testing using a composite femur with a segmental defect and an identical osteosynthesis plate for primary stabilisation with titanium screws. Both deflection of the femoral head and the gap alteration were measured with an optical measuring system with an accuracy of approximately 3 µm. For both screw modelling techniques a sufficient correlation of approximately 95% between numerical and experimental analysis was found. Furthermore, using structural elements for screw modelling the computational time could be reduced by 85% using hexahedral elements instead of tetrahedral elements for femur meshing. The automatically generated screw modelling offers a realistic simulation of the osteosynthesis fixation with screws in the adjacent

  11. Finite element analysis of osteosynthesis screw fixation in the bone stock: an appropriate method for automatic screw modelling.

    Directory of Open Access Journals (Sweden)

    Jan Wieding

    Full Text Available The use of finite element analysis (FEA has grown to a more and more important method in the field of biomedical engineering and biomechanics. Although increased computational performance allows new ways to generate more complex biomechanical models, in the area of orthopaedic surgery, solid modelling of screws and drill holes represent a limitation of their use for individual cases and an increase of computational costs. To cope with these requirements, different methods for numerical screw modelling have therefore been investigated to improve its application diversity. Exemplarily, fixation was performed for stabilization of a large segmental femoral bone defect by an osteosynthesis plate. Three different numerical modelling techniques for implant fixation were used in this study, i.e. without screw modelling, screws as solid elements as well as screws as structural elements. The latter one offers the possibility to implement automatically generated screws with variable geometry on arbitrary FE models. Structural screws were parametrically generated by a Python script for the automatic generation in the FE-software Abaqus/CAE on both a tetrahedral and a hexahedral meshed femur. Accuracy of the FE models was confirmed by experimental testing using a composite femur with a segmental defect and an identical osteosynthesis plate for primary stabilisation with titanium screws. Both deflection of the femoral head and the gap alteration were measured with an optical measuring system with an accuracy of approximately 3 µm. For both screw modelling techniques a sufficient correlation of approximately 95% between numerical and experimental analysis was found. Furthermore, using structural elements for screw modelling the computational time could be reduced by 85% using hexahedral elements instead of tetrahedral elements for femur meshing. The automatically generated screw modelling offers a realistic simulation of the osteosynthesis fixation with

  12. Prediction at long-term condyle screw fixation of temporomandibular joint implant: A numerical study.

    Science.gov (United States)

    Ramos, A; Duarte, R J; Mesnard, M

    2015-05-01

    The fixation of commercial temporomandibular joint (TMJ) implant is accomplished by using screws, which, in some cases, can lead to loosening of the implant. The aim of this study was to predict the evolution of fixation success of a TMJ. Numerical models using a Christensen TMJ implant were developed to analyze strain distributions in the adjacent mandibular bone. The geometry of a human mandible was developed based on computed tomography (CT) scans from a cadaveric mandible on which a TMJ implant was subsequently placed. In this study, the five most important muscle forces acting were applied and the anatomical conditions replicated. The evolution of fixation was defined according to bone response methodology focused in strain distribution around the screws. Strain and micromotions were analyzed to evaluate implant stability, and the evolution process conduct at three different stages: start with all nine screws in place (initial stage); middle stage, with three screws removed (middle stage), and end stage, with only three screws in place (final stage). With regard to loosening, the implant success fixation changed the strains in the bone between 21% and 30%, when considering the last stage. The most important screw positions were #1, #7, and #9. It was observed that, despite the commercial Christensen TMJ implant providing nine screw positions for fixation, only three screws were necessary to ensure implant stability and fixation success. PMID:25819477

  13. Pedicle Screw Fixation Study in Immature Porcine Spines to Improve Pullout Resistance during Animal Testing.

    Science.gov (United States)

    Le Cann, Sophie; Cachon, Thibaut; Viguier, Eric; Miladi, Lotfi; Odent, Thierry; Rossi, Jean-Marie; Chabrand, Patrick

    2015-01-01

    The porcine model is frequently used during development and validation of new spinal devices, because of its likeness to the human spine. These spinal devices are frequently composed of pedicle screws with a reputation for stable fixation but which can suffer pullouts during preclinical implantation on young animals, leading to high morbidity. With a view to identifying the best choices to optimize pedicle screw fixation in the porcine model, this study evaluates ex vivo the impact of weight (age) of the animal, the level of the vertebrae (lumbar or thoracic) and the type of screw anchorage (mono- or bi-cortical) on pedicle screw pullouts. Among the 80 pig vertebrae (90- and 140-day-old) tested in this study, the average screw pullout forces ranged between 419.9N and 1341.2N. In addition, statistical differences were found between test groups, pointing out the influence of the three parameters stated above. We found that the the more caudally the screws are positioned (lumbar level), the greater their pullout resistance is, moreover, screw stability increases with the age, and finally, the screws implanted with a mono-cortical anchorage sustained lower pullout forces than those implanted with a bi-cortical anchorage. We conclude that the best anchorage can be obtained with older animals, using a lumbar fixation and long screws traversing the vertebra and inducing bi-cortical anchorage. In very young animals, pedicle screw fixations need to be bi-cortical and more numerous to prevent pullout. PMID:26451947

  14. Pedicle Screw Fixation Study in Immature Porcine Spines to Improve Pullout Resistance during Animal Testing.

    Directory of Open Access Journals (Sweden)

    Sophie Le Cann

    Full Text Available The porcine model is frequently used during development and validation of new spinal devices, because of its likeness to the human spine. These spinal devices are frequently composed of pedicle screws with a reputation for stable fixation but which can suffer pullouts during preclinical implantation on young animals, leading to high morbidity. With a view to identifying the best choices to optimize pedicle screw fixation in the porcine model, this study evaluates ex vivo the impact of weight (age of the animal, the level of the vertebrae (lumbar or thoracic and the type of screw anchorage (mono- or bi-cortical on pedicle screw pullouts. Among the 80 pig vertebrae (90- and 140-day-old tested in this study, the average screw pullout forces ranged between 419.9N and 1341.2N. In addition, statistical differences were found between test groups, pointing out the influence of the three parameters stated above. We found that the the more caudally the screws are positioned (lumbar level, the greater their pullout resistance is, moreover, screw stability increases with the age, and finally, the screws implanted with a mono-cortical anchorage sustained lower pullout forces than those implanted with a bi-cortical anchorage. We conclude that the best anchorage can be obtained with older animals, using a lumbar fixation and long screws traversing the vertebra and inducing bi-cortical anchorage. In very young animals, pedicle screw fixations need to be bi-cortical and more numerous to prevent pullout.

  15. Experimental and Numerical Modeling of Screws Used for Rigid Internal Fixation of Mandibular Fractures

    Directory of Open Access Journals (Sweden)

    Bret Baack

    2008-05-01

    Full Text Available Experimental and numerical methods are used to explore the stresses generated around bone screws used in rigid internal fixation of mandibular fractures. These results are intended to aid in decisions concerning both the design and the use of these bone screws. A finite element (FE model of a human mandible is created with a fixated fracture in the parasymphyseal region. The mandibular model is anatomically loaded, and the forces exerted by the fixation plate onto the simplified screws are obtained and transferred to another finite element submodel of a screw implant embedded in a trilaminate block with material properties of cortical and cancellous bone. The stress in the bone surrounding the screw implant is obtained and compared for different screw configurations. The submodel analyses are further compared to and validated with simple axial experimental and numerical screw pull-out models. Results of the screw FE analysis (FEA submodel show that a unicortical screw of 2.6 mm major diameter and 1.0 mm pitch will cause less bone damage than a bicortical screw of 2.3 mm major diameter and 1.0 mm pitch. The results of this study suggest that bicortical drilling can be avoided by using screws of a larger major diameter.

  16. Comparison of two-transsacral-screw fixation versus triangular osteosynthesis for transforaminal sacral fractures.

    Science.gov (United States)

    Min, Kyong S; Zamorano, David P; Wahba, George M; Garcia, Ivan; Bhatia, Nitin; Lee, Thay Q

    2014-09-01

    Transforaminal pelvic fractures are high-energy injuries that are translationally and rotationally unstable. This study compared the biomechanical stability of triangular osteosynthesis vs 2-transsacral-screw fixation in the repair of a transforaminal pelvic fracture model. A transforaminal fracture model was created in 10 cadaveric lumbopelvic specimens. Five of the specimens were stabilized with triangular osteosynthesis, which consisted of unilateral L5-to-ilium lumbopelvic fixation and ipsilateral iliosacral screw fixation. The remaining 5 were stabilized with a 2-transsacral-screw fixation technique that consisted of 2 transsacral screws inserted across S1. All specimens were loaded cyclically and then loaded to failure. Translation and rotation were measured using the MicroScribe 3D digitizing system (Revware Inc, Raleigh, North Carolina). The 2-transsacral-screw group showed significantly greater stiffness than the triangular osteosynthesis group (2-transsacral-screw group, 248.7 N/mm [standard deviation, 73.9]; triangular osteosynthesis group, 125.0 N/mm [standard deviation, 66.9]; P=.02); however, ultimate load and rotational stiffness were not statistically significant. Compared with triangular osteosynthesis fixation, the use of 2 transsacral screws provides a comparable biomechanical stability profile in both translation and rotation. This newly revised 2-transsacral-screw construct offers the traumatologist an alternative method of repair for vertical shear fractures that provides biplanar stability. It also offers the advantage of percutaneous placement in either the prone or supine position. PMID:25350616

  17. Study of Bone-screw Surface Fixation in Lumbar Dynamic Stabilization

    Institute of Scientific and Technical Information of China (English)

    Yun-Gang Luo; Tao Yu; Guo-Min Liu; Nan Yang

    2015-01-01

    Background:We aimed to use the animal model of dynamic fixation to examine the interaction of the pedicle screw surface with surrounding bone,and determine whether pedicle screws achieve good mechanical stability in the vertebrae.Methods:Twenty-four goats aged 2-3 years had Cosmic(R) pedicle screws implanted into both sides of the L2-L5 pedicles.Twelve goats in the bilateral dynamic fixation group had fixation rods implanted in L2-L3 and L4-L5.Twelve goats in the unilateral dynamic fixation group had fixation rods randomly fixed on one side of the lumbar spine.The side that was not implanted with fixation rods was used as a static control group.Results:In the static control group,new bone was formed around the pedicle screw and on the screw surface.In the unilateral and bilateral dynamic fixation groups,large amounts of connective tissue formed between and around the screw threads,with no new bone formation on the screw surface; the pedicle screws were loose after the fixed rods were removed.The bone mineral density and morphological parameters of the region of interest (ROI) in the unilateral and bilateral dynamic fixation group were not significantly different (P > 0.05),but were lower in the fixed groups than the static control group (P < 0.05).This showed the description bone of the ROI in the static control group was greater than in the fixation groups.Under loading conditions,the pedicle screw maximum pull force was not significantly different between the bilateral and unilateral dynamic fixation groups (P > 0.05); however the maximum pull force of the fixation groups was significantly less than the static control group (P < 0.01).Conclusions:Fibrous connective tissue formed at the bone-screw interface under unilateral and bilateral pedicle dynamic fixation,and the pedicle screws lost mechanical stability in the vertebrae.

  18. Progressive slip after removal of screw fixation in slipped capital femoral epiphysis: two case reports

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    Engelsma Yde

    2012-11-01

    Full Text Available Abstract Introduction In slipped capital femoral epiphysis the femoral neck displaces relative to the head due to weakening of the epiphysis. Early recognition and adequate surgical fixation is essential for a good functional outcome. The fixation should be secured until the closure of the epiphysis to prevent further slippage. A slipped capital femoral epiphysis should not be confused with a femoral neck fracture. Case presentation Case 1 concerns a 15-year-old boy with an adequate initial screw fixation of his slipped capital femoral epiphysis. Unfortunately, it was thought that the epiphysis had healed and the screw was removed after 11 weeks. This caused new instability with a progressive slip of the femoral epiphysis and subsequently re-fixation and a subtrochanteric correction osteotomy was obligatory. Case 2 concerns a 13-year-old girl with persistent hip pain after screw fixation for slipped capital femoral epiphysis. The screw was removed as lysis was seen around the screw on the hip X-ray. This operation created a new unstable situation and the slip progressed resulting in poor hip function. A correction osteotomy with re-screw fixation was performed with a good functional result. Conclusion A slipped epiphysis of the hip is not considered ‘healed’ after a few months. Given the risk of progression of the slip the fixation material cannot be removed before closure of the growth plate.

  19. Serum albumin and fixation failure with cannulated hip screws in undisplaced intracapsular femoral neck fracture.

    Science.gov (United States)

    Riaz, O; Arshad, R; Nisar, S; Vanker, R

    2016-07-01

    Introduction Internal fixation of undisplaced intracapsular femoral neck fractures with cannulated hip screws is a widely accepted surgical technique, despite reported failure rates of 12%-19%. This study determined whether preoperative serum albumin levels are linked to fixation failure. Methods We retrospectively reviewed 251 consecutive undisplaced intracapsular femoral neck fracture patients treated with cannulated hip screws in a district general hospital. Preoperative albumin levels were measured, and the fixation technique, classification and posterior tilt on radiography assessed. Fixation failure was defined as a screw cut, avascular necrosis (AVN) or non-union. Results Of the patients, 185 were female and 66 male. The mean age was 77 years (range 60-101 years). Thirty seven (15%) patients had fixation failure: 10 (4%) due to AVN; 12 (5%) due to non-union; and 15 (6%) due to fixation collapse. Low serum albumin levels were significantly associated with failure (p=0.01), whereas gender (p=0.56), operated side (p=0.62), age (p=0.34) and screw configuration (p=0.42) were not. A posterior tilt angle greater than 20° on lateral radiography significantly predicted failure (p=0.002). Conclusions Preoperative serum albumin is an independent predictor of cannulated hip screw fixation failure in undisplaced femoral neck fractures. Nutritional status should therefore be considered when deciding between surgical fixation and arthroplasty to avoid the possibility of revision surgery, along with an increased risk of morbidity and mortality. PMID:27055409

  20. Anterior transarticular screw fixation as a conventional operation for rigid stabilization

    OpenAIRE

    Manabu Sasaki; Katsumi Matsumoto; Koichiro Tsuruzono; Kazuhiro Yoshimura; Katsuhiko Shibano; Kazuo Yonenobu

    2014-01-01

    Background: Anterior transarticular screw (ATS) fixation is a useful surgical option for atlantoaxial (AA) stabilization. This report presents a revised ATS method for AA fusion. Methods: A 79-year-old male presented with AA instability attributed both to an old odontoid fracture and severe degeneration of the lateral atlantoaxial joints (LAAJs). ATS fixation was performed through the conventional anterior cervical approach. The longest screw trajectories were planned preoperatively using...

  1. Translaminar screw fixation of a kyphosis of the cervical and thoracic spine in neurofibromatosis.

    Science.gov (United States)

    Gardner, A; Millner, P; Liddington, M; Towns, G

    2009-09-01

    The spinal manifestations of neurofibromatosis include cervicothoracic kyphosis, in which scalloping of the vertebral body and erosion of the pedicles may render conventional techniques of fixation impossible. We describe a case of cervicothoracic kyphosis managed operatively with a vascularised fibular graft anteriorly across the apex of the kyphus, followed by a long posterior construct using translaminar screws, which allow segmental fixation in vertebral bodies where placement of the pedicle screws was impracticable. PMID:19721057

  2. Pedicle Screw Fixation Study in Immature Porcine Spines to Improve Pullout Resistance during Animal Testing

    OpenAIRE

    Le Cann, Sophie; Cachon, Thibaut; Viguier, Eric; MILADI, Lotfi; Odent, Thierry; Rossi, Jean-Marie; Chabrand, Patrick

    2015-01-01

    The porcine model is frequently used during development and validation of new spinal devices, because of its likeness to the human spine. These spinal devices are frequently composed of pedicle screws with a reputation for stable fixation but which can suffer pull-outs during preclinical implantation on young animals, leading to high morbidity. With a view to identifying the best choices to optimize pedicle screw fixation in the porcine model, this study evaluates ex vivo the impact of weight...

  3. Effect of Long-Term Cycling Load for Abutment Screw Fixation in Implant Prosthodontics

    OpenAIRE

    Szabo, Gy.; L. Kocsis; Szanto, P.; Thamm, F.

    2002-01-01

    The aim of this in vitro study was to use rotational tests on commercially available abutment screws to evaluate their potential for preload generation and to follow changes in torque by using newer fixation geometry on the interface of the implant-abutment screw joint. Five identical implant/abutment assemblies were chosen from each of the following systems: external hex with standard abutment and Replace with TorgTite screw (Nobel Biocare), Camlog universal abutment (Altatec Biotechnologies...

  4. Polymethylmethacrylate-augmented screw fixation for stabilization in metastatic spinal tumors. Technical note.

    Science.gov (United States)

    Jang, Jee Soo; Lee, Sang Ho; Rhee, Chang Hun; Lee, Seung Hoon

    2002-01-01

    Screw fixation augmented with polymethylmethacrylate (PMMA) or some other biocompatible bone cement has been used in patients with osteoporosis requiring spinal fusion. No clinical studies have been conducted on PMMA-augmented screw fixation for stabilization of the vertebral column in patients with metastatic spinal tumors. The purpose of this study was to determine whether screw fixation augmented with PMMA might be suitable in patients treated for multilevel metastatic spinal tumors. Ten patients with metastatic spinal tumors involving multiple vertebral levels underwent stabilization procedures in which PMMA was used to augment screw fixation after decompression of the spinal cord. Within 15 days, partial or complete relief from pain was obtained in all patients postoperatively. Two of four patients in whom neurological deficits caused them to be nonambulatory before surgery were able to ambulate postoperatively. Neither collapse of the injected vertebral bodies nor failure of the screw fixation was observed during the mean follow-up period of 6.7 months. Screw fixation augmented with PMMA may offer stronger stabilization and facilitate the instrumentation across short segments in the treatment of multilevel metastatic spinal tumors. PMID:11795702

  5. Anterior transarticular screw fixation as a conventional operation for rigid stabilization

    Directory of Open Access Journals (Sweden)

    Manabu Sasaki

    2014-01-01

    Full Text Available Background: Anterior transarticular screw (ATS fixation is a useful surgical option for atlantoaxial (AA stabilization. This report presents a revised ATS method for AA fusion. Methods: A 79-year-old male presented with AA instability attributed both to an old odontoid fracture and severe degeneration of the lateral atlantoaxial joints (LAAJs. ATS fixation was performed through the conventional anterior cervical approach. The longest screw trajectories were planned preoperatively using multiplanar reconstruction computed tomography (CT scans, with entry points of the screws situated at the midpoint on the inferior border of the axial body. The surgical exposure was limited to opening at the entry points alone. Our retractor of choice was the Cusco speculum; it sufficiently secured space for utilizing the required instruments for screw placement while offering sufficient protection of soft tissues. Cannulated full-threaded bicortical screws stabilized the LAAJs. Screw insertion required a significant amount of coronal angulation up to the superior articular process of the atlas under open-mouth and lateral fluoroscopy image guidance. After ATS fixation, bone grafting was performed between the posterior laminae of the axis and the atlas through a conventional posterior approach. Results: Bony fusion between the atlas and the axis was confirmed radiographically. Arthrodesis of the LAAJs occurred despite no bone grafting. Conclusions: Rigid fixation of the LAAJs was obtained by our ATS technique, indicating that it is an alternative method for AA fixation when posterior rigid internal fixation is not applicable.

  6. Feasibility study on posterior laminar screw fixation techniques in the axis

    Institute of Scientific and Technical Information of China (English)

    HU Yong; HE Xian-feng; GU Yong-jie; XU Rong-ming; MA Wei-hu; RUAN Yong-ping; Lin Rong

    2010-01-01

    Objective: To get morphologic param-eters of Chinese adults through observation and measure-ment on axial laminas, to evaluate the feasibility of placing axial laminar screws and to introduce the technique.Methods: Relative parameters of 28 sets of fresh Chi-nese adults' axial specimens, including distance from the superior and inferior entry points of axial laminar screws to the superior margins of axial laminas, superior, middle, infe-rior thickness and height of the axial laminas, length and angle of the axial laminar screw trajectories, distance from the entry points of axial laminar screws to the transverse foramen and central points of the inferior articular process, were measured with a digital caliper and a goniometer.Data were statistically analyzed.Results: Averagely, distance from the superior and inferior entry points of axial laminar screws to the superior margins of axial laminas was 5 mm and 9 ram, superior, middle, inferior thickness and the height of the axial laminas were 3.2 mm, 6.7 ram, 5.5 nun and 12.8 mm respectively, and the length of the superior and inferior axial laminar screw trajectories was 26.2 mm and 25.5 mm, respectively.Conclusions: It is feasible and reliable to apply poste-rior laminar screw fixation techniques to the axes of Chinese adults.Also the C_2 laminar screw fixation technique can be taken as a supplementary to conventional posterior screw fixations of C_2.

  7. Sextant percutaneous pedicle screw fixation for correcting single-segment thoracolumbar fractures

    Institute of Scientific and Technical Information of China (English)

    Ming Jiang-hua; Zheng Hui-feng; Zhao Qi; Chen Qing; Wang Gang

    2014-01-01

    BACKGROUND:Though the effects of conservative or traditional open reduction and internal fixation in the treatment of thoracolumbar fractures are reliable and satisfactory for most cases, two methods also have shortages. Minimal-invasive percutaneous pedicle screw system provides a new available method. OBJECTIVE:To investigate the clinical effect of Sextant percutaneous pedicle screw system in the treatment of thoracolumbar fractures. METHODS:A total of 55 patients, who had undergone percutaneous pedicle screw fixation using Sextant system (25 patients) or traditional open internal fixation (30 patients) for single-level vertebral body compression fractures in Department of Orthopedics of Renmin Hospital of Wuhan University from February 2011 to January 2013, were enrol ed in this study. RESULTS AND CONCLUSION:Except two patients in traditional open internal fixation group were lost after discharge, al other patients were fol owed up for 8-14 months. Operative time, intraoperative blood loss, postoperative drainage amount and hospital day were better in percutaneous pedicle screw fixation group than in the traditional open internal fixation group (P0.05). The results show that percutaneous pedicle screw fixation using Sextant system has a satisfactory outcome in the treatment of thoracolumbar fractures. However, obeying indication strictly is very important for clinical application.

  8. S-1 and S-2-alar-iliac screw fixation via intraoperative navigation.

    Science.gov (United States)

    Pham, Martin H; Jakoi, Andre M; Hsieh, Patrick C

    2016-07-01

    Adult deformity patients often require fixation to the sacrum and pelvis for construct stability and improved fusion rates. Although certain sacropelvic fixation techniques can be challenging, the availability of intraoperative navigation has made many of these techniques more feasible. In this video case presentation, the authors demonstrate the techniques of S-1 bicortical screw and S-2-alar-iliac screw fixation under intraoperative navigation in a 67-year-old female. This instrumentation placement was part of an overall T-10-pelvis construct for the correction of adult spinal deformity. The video can be found here: https://youtu.be/3HZo-80jQr8 . PMID:27364427

  9. Fixation strength of biocomposite wedge interference screw in ACL reconstruction: effect of screw length and tunnel/screw ratio. A controlled laboratory study

    Directory of Open Access Journals (Sweden)

    Herrera Antonio

    2010-06-01

    Full Text Available Abstract Background Primary stability of the graft is essential in anterior cruciate ligament surgery. An optimal method of fixation should be easy to insert and provide great resistance against pull-out forces. A controlled laboratory study was designed to test the primary stability of ACL tendinous grafts in the tibial tunnel. The correlation between resistance to traction forces and the cross-section and length of the screw was studied. Methods The tibial phase of ACL reconstruction was performed in forty porcine tibias using digital flexor tendons of the same animal. An 8 mm tunnel was drilled in each specimen and two looped tendons placed as graft. Specimens were divided in five groups according to the diameter and length of the screw used for fixation. Wedge interference screws were used. Longitudinal traction was applied to the graft with a Servohydraulic Fatigue System. Load and displacement were controlled and analyzed. Results The mean loads to failure for each group were 295,44 N (Group 1; 9 × 23 screw, 564,05 N (Group 2; 9 × 28, 614,95 N (Group 3; 9 × 35, 651,14 N (Group 4; 10 × 28 and 664,99 (Group 5; 10 × 35. No slippage of the graft was observed in groups 3, 4 and 5. There were significant differences in the load to failure among groups (ANOVA/P Conclusions Longer and wider interference screws provide better fixation in tibial ACL graft fixation. Short screws (23 mm do not achieve optimal fixation and should be implanted only with special requirements.

  10. Monoaxial Pedicle Screws Are Superior to Polyaxial Pedicle Screws and the Two Pin External Fixator for Subcutaneous Anterior Pelvic Fixation in a Biomechanical Analysis

    OpenAIRE

    Rahul Vaidya; Ndidi Onwudiwe; Matthew Roth; Anil Sethi

    2013-01-01

    Purpose. Comparison of monoaxial and polyaxial screws with the use of subcutaneous anterior pelvic fixation. Methods. Four different groups each having 5 constructs were tested in distraction within the elastic range. Once that was completed, 3 components were tested in torsion within the elastic range, 2 to torsional failure and 3 in distraction until failure. Results. The pedicle screw systems showed higher stiffness (4.008 ± 0.113 Nmm monoaxial, 3.638 ± 0.108 Nmm Click-x; 3.634 ± 0.147 Nmm...

  11. Implant failure in a proximal femoral fracture treated with dynamic hip screw fixation.

    Science.gov (United States)

    Dabis, John; Abdul-Jabar, Hani B; Dabis, Hosam

    2015-01-01

    Dynamic hip screw fixation is a common orthopaedic procedure and to date, still can cause difficulties to the senior trauma surgeon. We present a case where an extra-capsular fracture of the proximal femur was managed with a dynamic hip screw (DHS) fixation. She proceeded to the operating theatre, where the fracture was stabilized with a 75-mm DHS and short-barrelled plate. The implant position was checked with intraoperative screening and the position accepted. Following attempted mobilization at 11 days post-operatively, the patient developed a recurrence of her preoperative pain. X-ray showed that the implant screw had separated from the barrel. Later scrutiny of the intraoperative screening films revealed that the barrel and screw were not engaged at the time of surgery. Intraoperative screening films should be carefully checked to ensure congruity of implant components. PMID:26136561

  12. Cervical pedicle screw fixation at C6 and C7 A cadaveric study

    Directory of Open Access Journals (Sweden)

    Ye Li

    2015-01-01

    Conclusion: The intersection of the horizontal line through the midpoint of the transverse process root and vertical line through the intersection of the posterolateral and posterior planes of the isthmus can be used as an entry point for C6 and C7 pedicle screw fixation. The screws should be inserted at 60 or 90° with the posterolateral isthmus in the horizontal plane and at 75° with the posterior isthmus in the sagittal plane. The LSC should not exceed 30 mm.

  13. Posterior fixation and fusion with atlas pedicle screw system for upper cervical diseases

    Institute of Scientific and Technical Information of China (English)

    LI Lei; ZHOU Feng-hua; WANG Huan; CUI Shao-qian

    2008-01-01

    Objective: To evaluate the feasibility, safety and efficacy of atlas pedicle screws system fixation and fusion for the treatment of upper cervical diseases. Methods: Twenty-three consecutive patients with up-per cervical disorders requiring stabilization, including 19 cases of atlantoaxial dislocation (4 congenital odontoid disconnections, 6 old odontoid fractures, 4 fresh odontoid fractures of Aderson Ⅱ C, 3 ruptures of the C1 transverse ligament, and 2 fractures ofC1), 2 cases ofC2 tumor (instability after the resection of the tumors), and 2 giant neurilemomas of C2-C3(instability after resection of the tumors), were treated by posterior fixation and fusion with the atlas pedicle screw system, in which the screws were inserted through the posterior arch of Cr The operative time, bleeding volume and complications were reported. All patients were immobilized without external fixation or with rigid cervical collars for 1-3 months. All patients were followed up and evaluated with radiographs and CT. Results: In the 23 patients, 46 C1 pedicle screws, 42 C2 pedicle screws and 6 lower cervical lateral mass screws and 2 lower cervical pedicle screws were placed. The mean operative time and bleeding volume was 2.7 hours and 490 ml respectively. No intraoperative complications were directly related to surgical technique. No neurological, vascular or infective complications were encountered. All patients were followed up for 3-36 months (average 15 months). Firm bony fusion was documented in all patients after 3-6 months. One patient with atlas fracture showed anterior occipitocervical fusion. There was no implant failure. Conclusions: Posterior fixation and fusion of the atlas pedicle screw system is feasible and safe for the treatment of upper cervical diseases, and may be applicable to a larger number of patients.

  14. Hydroxyapatite composite resin cement augmentation of pedicle screw fixation.

    Science.gov (United States)

    Turner, Alexander W L; Gillies, R Mark; Svehla, Martin J; Saito, Masanobu; Walsh, William R

    2003-01-01

    Pedicle screw stability is poor in osteopenic vertebrae attributable, in part, to low screw-bone interface strength. The current authors examined cement augmentation using a low curing temperature hydroxyapatite and bis-phenol-A glycidol methacrylate-based composite resin. This cement may stiffen the screw-bone interface and reduce the harmful effects associated with polymethylmethacrylate regarding temperature and toxic monomer. Thirty-five lumbar vertebrae from human cadavers were instrumented with pedicle screws, with one pedicle previously injected with cement and the other as the control. Caudocephalad toggling of +/- 1 mm for 1600 cycles was applied to the pedicle screws, and the resulting forces supported by the implant-bone interface were captured by a load cell. A curve was constructed from the peak caudal load for each cycle and three mechanical measures parameterized this curve: (1) initial load; (2) rate of load decay during the first 400 cycles; and (3) final load. The initial load increased by 16% as a result of cement augmentation, the final load increased by 65%, and the rate of load decay decreased by 59%. Cement augmentation of pedicle screws increased the stiffness and stability of the screw-bone interface. PMID:12579026

  15. Posterior pelvic ring fractures: Closed reduction and percutaneous CT-guided sacroiliac screw fixation

    International Nuclear Information System (INIS)

    Purpose. To assess the midterm results of closed reduction and percutaneous fixation (CRPF) with computed tomography (CT)-guided sacroiliac screw fixation in longitudinal posterior pelvic ring fractures. Methods. Thirteen patients with 15 fractures were treated. Eleven patients received a unilateral, two a bilateral, screw fixation. Twenty-seven screws were implanted. Continuous on-table traction was used in six cases. Mean radiological follow-up was 13 months. Results. Twenty-five (93%) screws were placed correctly. There was no impingement of screws on neurovascular structures. Union occurred in 12 (80%), delayed union in 2 (13%), and nonunion in 1 of 15 (7%) fractures. There was one screw breakage and two axial dislocations. Conclusion. Sacroiliac CRPF of longitudinal fractures of the posterior pelvic ring is technically simple, minimally invasive, well localized, and stable. It should be done by an interventional/surgical team. CT is an excellent guiding modality. Closed reduction may be a problem and succeeds best when performed as early as possible

  16. Percutaneous screw fixation of a vertebral pedicle fracture under CT-guidance: A new technique

    International Nuclear Information System (INIS)

    We report on a new minimally invasive technique for the vertebral pedicle fracture after placement of a prosthetic disc. This intervention is an adaptation of CT-guided sacroiliac and acetabular fracture screw fixation. This type of procedure enables the perfect placement and measurement of the screw, as well as an extremely small incision under local anesthesia. CT guided Transpedicular fixation could be a useful strategy in the treatment of future cases involving poorly healing pedicle fractures causing persistent symptoms. This intervention confirms the range of capacities of CT scan-controlled interventions in terms of precision, safety, speed, minimal invasiveness, rapid return to everyday activity and consequently, economical management.

  17. Comparison of migration behavior between single and dual lag screw implants for intertrochanteric fracture fixation

    Directory of Open Access Journals (Sweden)

    Katonis Pavlos G

    2009-05-01

    Full Text Available Abstract Background Lag screw cut-out failure following fixation of unstable intertrochanteric fractures in osteoporotic bone remains an unsolved challenge. This study tested if resistance to cut-out failure can be improved by using a dual lag screw implant in place of a single lag screw implant. Migration behavior and cut-out resistance of a single and a dual lag screw implant were comparatively evaluated in surrogate specimens using an established laboratory model of hip screw cut-out failure. Methods Five dual lag screw implants (Endovis, Citieffe and five single lag screw implants (DHS, Synthes were tested in the Hip Implant Performance Simulator (HIPS of the Legacy Biomechanics Laboratory. This model simulated osteoporotic bone, an unstable fracture, and biaxial rocking motion representative of hip loading during normal gait. All constructs were loaded up to 20,000 cycles of 1.45 kN peak magnitude under biaxial rocking motion. The migration kinematics was continuously monitored with 6-degrees of freedom motion tracking system and the number of cycles to implant cut-out was recorded. Results The dual lag screw implant exhibited significantly less migration and sustained more loading cycles in comparison to the DHS single lag screw. All DHS constructs failed before 20,000 cycles, on average at 6,638 ± 2,837 cycles either by cut-out or permanent screw bending. At failure, DHS constructs exhibited 10.8 ± 2.3° varus collapse and 15.5 ± 9.5° rotation around the lag screw axis. Four out of five dual screws constructs sustained 20,000 loading cycles. One dual screw specimens sustained cut-out by medial migration of the distal screw after 10,054 cycles. At test end, varus collapse and neck rotation in dual screws implants advanced to 3.7 ± 1.7° and 1.6 ± 1.0°, respectively. Conclusion The single and double lag screw implants demonstrated a significantly different migration resistance in surrogate specimens under gait loading simulation with

  18. Titanium screw entered into maxillary sinus: a rare incident during rigid fixation of the porous polyethylene implant in enophthalmos correction.

    Science.gov (United States)

    Fu, Xi; Liu, JianFeng; Zou, Chong; Rui, Lu; Gui, Lai

    2014-07-01

    Screw fixation is used for accurate augmentation by porous polyethylene implant in traumatic enophthalmos correction to avoid complications such as migration and protrusion. We report an incident of titanium screw entered into the maxillary sinus during enophthalmos correction with porous polyethylene implant. Such incident could be avoided by standard manipulation. We here present the rare case and offer proposals for the screw fixation of porous polyethylene implant during traumatic enophthalmos correction. PMID:25006927

  19. Design of three-dimensional visualization based on the posterior lumbar pedicle screw fixation

    Directory of Open Access Journals (Sweden)

    Kai XU

    2011-09-01

    Full Text Available Objective To establish a three-dimensional visualization model of posterior lumbar pedicle screw fixation.Methods A patient with lumbar intervertebral disc hernia and another patient with compression fracture of lumbar vertebra were involved in the present study.Both patients underwent multi-slice spiral CT scan before and after lumbar pedicle screw fixation.The degree of preoperative vertebral compression,vertebral morphology before and after surgery,postoperative pedicle screw position,and decompression effects were observed.The original data of the multi-slice spiral CT were inputted into the computer.The three-dimensional reconstructed images of the lumbar and implanted screws were obtained using the software Amira 4.1 to show the three-dimensional shape of the lumbar vertebrae before and after surgery and the location of the implanted screws.Results The morphology and structure of the lumbar vertebrae before and after surgery and of the implanted screws were reconstructed using the digital navigation platform.The reconstructed 3D images could be displayed in multicolor,transparent,or arbitrary combinations.In the 3D surface reconstruction images,the location and structure of the implanted screws could be clearly observed,and the decompression of the spinal cord or nerve roots and the severity of the fracture and the compression of lumbar vertebrae could be fully evaluated.The reconstructed images before operation revealed the position of the vertebral pedicles and provided reference for intraoperative localization.Conclusions The three-dimensional computerized reconstructions of lumbar pedicle screw fixation may be valuable in basic research,clinical experiment,and surgical planning.The software Amira is one of the bases of three-dimensional reconstruction.

  20. Short Segment Fixation Versus Short Segment Fixation With Pedicle Screws at the Fracture Level for Thoracolumbar Burst Fracture

    Directory of Open Access Journals (Sweden)

    Anghel S

    2014-04-01

    Full Text Available Objective: The most prevailing surgical procedure in the treatment of thoracolumbar burst fractures, Short Segment Fixation (SSF, is often followed by loss of correction or hardware failure which may be significant enough to require another surgical intervention. In order to take advantage of its benefits but to avoid or diminish the risk and impact of associated drawbacks, some other alternatives have been lately developed among which we refer to short segment fixation with intermediate screws (SSF+IS. This article provides a comparative picture over the effectiveness of the two above-mentioned surgical treatments, focusing on their potential to prevent the loss of correction.

  1. Initial stability of cementless acetabular cups: press-fit and screw fixation interaction—an in vitro biomechanical study

    OpenAIRE

    Tabata, Tomonori; Kaku, Nobuhiro; Hara, Katsutoshi; Tsumura, Hiroshi

    2014-01-01

    Background Press-fit and screw fixation are important technical factors to achieve initial stability of a cementless acetabular cup for good clinical results of total hip arthroplasty. However, how these factors affect one another in initial cup fixation remains unclear. Therefore, this study aimed to evaluate the mutual influence between press-fit and screw fixation on initial cup stability. Methods Foam bone was subjected to exact hemispherical-shape machining to diameters of 48, 48.5 and 4...

  2. Collateral ligament reconstruction of the chronic thumb injury with bio-tenodesis screw fixation

    DEFF Research Database (Denmark)

    Gvozdenovic, Robert; Boeckstyns, Michel

    2014-01-01

    We describe a new technique for the reconstruction of chronic lesions of the collateral ligaments of the metacarpophalangeal ligaments of the thumb, using a Bio-Tenodesis screw for the fixation of a tendon graft in a triangular manner with proximal apex and allowing early mobilization, starting 2...

  3. Fibular grafting with cannulated hip screw fixation in late femoral neck fracture in young adults

    Directory of Open Access Journals (Sweden)

    Goyal R

    2006-01-01

    Full Text Available Background: We reviewed the operative results of fibular bone graft with cannulated hip screw fixation in femoral neck fracture in young adults. Method: Sixteen young adults with femoral neck fracture were treated by fibular bone graft with cannulated hip screw fixation. All the fractures were more than 3 weeks old. Results: Results were assessed in 15 patients while one patient died due to complications not related to surgery. Union occurred in all 15 patients. One patient had intra-operative complication in the form of screw cut out with graft in the joint space. The average fallow up was 24.4 months. Out of 15 patients assessed clinico-radiologically 11 showed good results, 3 had fair while 1 had poor result. Conclusion: We conclude that this is a simple and cost effective procedure for late femoral fleck fracture in young adults with good results.

  4. Significantly lower femoral neck growth in screw fixation of the asymptomatic contralateral hip in unilateral slipped capital femoral epiphysis.

    Science.gov (United States)

    Wölfle-Roos, Julia V; Urlaub, Stefanie; Reichel, Heiko; Taurman, Rita

    2016-05-01

    There is an ongoing debate on which fixation technique should be preferred for the prophylactic fixation of the asymptomatic contralateral hip in slipped capital femoral epiphysis (SCFE). In the case of Kirschner-wire (K-wire) fixation, there is a possibility of secondary loss of fixation because of longitudinal growth of the physis, whereas in screw fixation, physeal growth of the femoral neck might be impaired. The aim of this matched-pair study was to compare the longitudinal growth of the femoral neck in screw fixation versus K-wire fixation of the asymptomatic contralateral hip in SCFE. All 18 patients (female : male=3 : 15), who had undergone screw fixation of the asymptomatic contralateral hip between 9/2001 and 9/2011, were matched according to age, bone age, sex, and time to follow-up to another 18 patients with K-wire fixation. The length of the femoral neck of the contralateral hip was measured in parallel to either screw or K-wire from the apex of the femoral head to the opposite cortical bone. The ratio of the femoral neck length measured directly after surgery and on follow-up was defined as femoral neck growth. There was no significant difference between groups with respect to age, modified Oxford Bone age score, and time to follow-up. We found a significant difference in femoral neck growth between patients with screw fixation (5.5±4.3%) compared with K-wire fixation (8.9±5.7%, P=0.048 matched Wilcoxon test). The difference in femoral neck growth of patients with K-wire or screw fixation of the contralateral asymptomatic hip in SCFE was small, but statistically significant. Thus, despite high rates of secondary loss of fixation, K-wire fixation should still be considered, especially in very young patients. PMID:26919622

  5. Short segmental pedicle screw fixation combined with percutaneous vertebroplasty in treatment of nonadjacent thoracolumbar fractures

    Institute of Scientific and Technical Information of China (English)

    HE Qing-yi; XU Jian-zhong

    2009-01-01

    To evaluate the short-term outcomes of short segmental pedicle screw fixation combined with per-cutaneous vertebroplasty in treatment of nonadjacent tho-racolumbar fractures. Methods: Twenty patients who suffered from nonadja-cent thoracolumbar fractures were treated by short segmental pedicle screw fixation for burst fracture and by percutane-ous vertebroplasty for compression fracture. X-rays, CT and MRI scans were conducted using the same protocol before and after surgery and during follow-up. Pre- and post-operative American Spinal Injury Association (ASIA) grades, fusion of fracture sites, visual analog scale (VAS) of back pain, and Oswestry disability index (ODI) were accessed. Results: All patients were followed up for an average period of 12 months. The sagittal profile of the thoracolum-bar spine was restored satisfactorily. No patient had neuro-logic deterioration after surgery, and 9 patients with incom-plete lesions improved postoperatively by at least one ASIA grade. The fusion rate was 100%. The average VAS of back pain was 7.6 preoperatively and 3.2 postoperatively. The average ODI was 72.5 preoperatively and 35.5 postoperatively. Conclusions: Short segmental pedicle screw fixation combined with percutaneous vertebroplasty in treatment of nonadjacent thoracolumbar fractures exhibits such advan-tages as preserving functional segment units, reliable fixation, good neurologic recovery and early mobilization and, therefore, is suitable for treating nonadjacent thora-columbar fractures.

  6. Percutaneous Screw Fixation of Crescent Fracture-Dislocation of the Sacroiliac Joint.

    Science.gov (United States)

    Shui, Xiaolong; Ying, Xiaozhou; Mao, Chuanwan; Feng, Yongzeng; Chen, Linwei; Kong, Jianzhong; Guo, Xiaoshan; Wang, Gang

    2015-11-01

    Crescent fracture-dislocation of the sacroiliac joint (CFDSIJ) is a type of lateral compression pelvic injury associated with instability. Open reduction and internal fixation is a traditional treatment of CFDSIJ. However, a minimally invasive method has never been reported. The purpose of this study was to assess the outcome of closed reduction and percutaneous fixation for different types of CFDSIJ and present their clinical outcome. The authors reviewed 117 patients diagnosed with CFDSIJ between July 2003 and July 2013. Closed reduction and percutaneous fixation was performed in 73 patients. Treatment selection was based on Day's fracture classification. For type I fractures, fixation perpendicular to the fracture line were performed. For type II fractures, crossed fixation was performed. For type III fractures, fixation was performed with iliosacral screws. Forty-four patients were treated by open reduction and plate fixation. Demographics, fracture pattern distribution, blood loss, incision lengths, revision surgeries, radiological results, and functional scores were compared. All 117 patients were followed for more than 6 months (mean, 14 months [range, 6-24 months]). Blood loss, extensive exposure, duration of posterior ring surgery, duration of hospital stay, and infection rates were lower in the closed group (P<.01). Patients in the closed group achieved better functional performance (P<.01). There were no significant differences in reduction quality (P=.32), revision surgery rates (P=.27), and iatrogenic neurologic injuries (P=.2) between the 2 groups. The authors' results indicate that closed reduction and percutaneous fixation is a safe and effective surgical method for CFDSIJ. PMID:26558677

  7. Cement embolism into the venous system after pedicle screw fixation: case report, literature review, and prevention tips

    Directory of Open Access Journals (Sweden)

    Ghassan Kerry

    2013-09-01

    Full Text Available The strength of pedicle screws attachment to the vertebrae is an important factor affecting their motion resistance and long term performance. Low bone quality, e.g. in osteopenic patients, keeps the screw bone interface at risk for subsidence and dislocation. In such cases, bone cement could be used to augment pedicle screw fixation. But its use is not free of risk. Therefore, clinicians, especially spine surgeons, radiologists, and internists should become increasingly aware of cement migration and embolism as possible complications. Here, we present an instructive case of cement embolism into the venous system after augmented screw fixation with fortunately asymptomatic clinical course. In addition we discuss pathophysiology and prevention methods as well as therapeutic management of this potentially life-threatening complication in a comprehensive review of the literature. However, only a few case reports of cement embolism into the venous system were published after augmented screw fixation.

  8. Assessment of penetration of dorsal screws after fixation of the distal radius using ultrasound: cadaveric study.

    Science.gov (United States)

    Williams, D; Singh, J; Heidari, N; Ahmad, M; Noorani, A; Di Mascio, L

    2016-02-01

    Introduction Volar locking plates are used to treat unstable and displaced fractures of the distal radius. Potential advantages of stable anatomical reduction (eg early mobilisation) can be limited by penetration of dorsal screws, leading to synovitis and potential rupture of extensor tendons. Despite intraoperative imaging, penetration of dorsal screws continues to be a problem in volar plating of the distal radius. Ultrasound is a well recognised, readily available, diagnostic tool used to assess soft-tissue impingement by orthopaedic hardware. In this cadaveric study, we wished to ascertain the sensitivity and specificity of ultrasound for identification of protrusion of dorsal screws after volar plating of the distal radius. Methods Four adult, unpaired phenol-embalmed cadaveric distal radii were used. A VariAx™ Distal Radius Volar Locking Plate system (Stryker, Kalamazoo, MI, USA) was employed for instrumented fixation. A portable SIUI CTS 900 ultrasound machine (Providian Medical, Eastlake, OH, USA) was used to image the dorsal cortex to ascertain screw penetration. Results Specificity and sensitivity of ultrasound for detection of screw protrusion through the dorsal cortex was 100%. Conclusions Ultrasound was found to be a safe and accurate method for assessment of dorsal-screw penetration through the dorsal cortex of the radius after volar plating of the distal radius. It also aids diagnosis of associated tendon disorders (eg tenosynovitis) that might cause pain and limit wrist function. PMID:26829667

  9. Transpedicular screw fixation for type II Hangman's fracture: a motion preserving procedure.

    Science.gov (United States)

    ElMiligui, Yasser; Koptan, Wael; Emran, Ihab

    2010-08-01

    Opinions have varied regarding the optimal treatment of an unstable Hangman's fracture. C2 pedicle screw instrumentation is a biomechanically strong fixation which although done through a simple posterior approach, is a technically demanding procedure. This prospective, non-randomized multicentre study included 15 consecutive patients with displaced type II traumatic spondylolisthesis of the axis. There were nine males and six females with a mean age of 37 years at surgery. The cause of injury was a road traffic accident in 11 patients and a fall from height in 4 patients. All patients had a single stage reduction and direct transpedicular screw fixation through the C2 pedicles. During follow-up, clinical evaluation and plain X-rays were performed at each visit; at 6-month follow-up, additional dynamic lateral flexion/extension views and a CT scan were performed. The average follow-up period was 32 months (range 25-56 months). At final follow-up, all patients were asymptomatic and regained a good functional outcome with no limitation of range of motion; all the patients showed solid union with no implant failure. There were no neurological complications. At 6-month follow-up, CT evaluation showed fusion in all patients and an adequate position of 28 screws. Two pedicle screws (6.6%) showed minimal (defined as <2 mm) intrusion; one into the spinal canal and the other into the vertebral foreamen. Transpedicular screw fixation through the C2 pedicles is a safe and effective method in treating type II traumatic spondylolisthesis of the axis resulting in good clinical and radiological outcomes. Adequate reduction was achieved and motion segments were preserved with its use. PMID:20401619

  10. Sliding-screw plate fixation of proximal femoral fractures: Radiographic assessment

    International Nuclear Information System (INIS)

    The sliding compression screw-sideplate combination is currently the most widely employed device for internal fixation of stable and unstable intertrochanteric fractures of the femur. The normal and abnormal radiogrpahic appearances of this device in the immediate post-operative period are discussed. Potential long-term complications including mal- or non-union, intra-articular penetration, metal failure, rotation of the proximal fracture fragment, disengagement, trochanteric bursitis, leg length discrepancy, delayed cervical stress fracture, and ischemic necrosis are reviewed. (orig.)

  11. "NIMS technique" for minimally invasive spinal fixation using non-fenestrated pedicle screws: A technical note

    Directory of Open Access Journals (Sweden)

    Alugolu Rajesh

    2015-01-01

    Full Text Available Study Design: Case series. Objective: To reduce the cost of minimally invasive spinal fixation. Background: Minimally invasive spine (MIS surgery is an upcoming modality of managing a multitude of spinal pathologies. However, in a resource-limited situations, using fenestrated screws (FSs may prove very costly for patients with poor affordability. We here in describe the Nizam′s Institute of Medical Sciences (NIMS experience of using routine non-FSs (NFSs for transpedicular fixation by the minimally invasive way to bridge the economic gap. Materials and Methods: A total of 7 patients underwent NFS-minimally invasive spine (MIS surgery. Male to female distribution was 6:1. The average blood loss was 50 ml and the mean operating time was 2 and 1/2 h. All patients were mobilized the very next day after confirming the position of implants on X-ray/computed tomography. Results: All 7 patients are doing well in follow-up with no complaints of a backache or fresh neurological deficits. There was no case with pedicle breach or screw pullout. The average cost of a single level fixation by FS and NFS was `1, 30,000/patient and `32,000/patient respectively ($2166 and $530, respectively. At the end of 1-year follow-up, we had two cases of screw cap loosening and with a displacement of the rod cranio-caudally in one case which was revised through the same incisions. Conclusions: Transpedicular fixation by using NFS for thoracolumbar spinal pathologies is a cost-effective extension of MIS surgery. This may extend the benefits to a lower socioeconomic group who cannot afford the cost of fenestrated screw (FS.

  12. Technique and nuances of an S-2 alar iliac screw for lumbosacral fixation in patients with transitional and normal anatomy.

    Science.gov (United States)

    Ohya, Junichi; Vogel, Todd D; Dhall, Sanjay S; Berven, Sigurd; Mummaneni, Praveen V

    2016-07-01

    S-2 alar iliac (S2AI) screw fixation has recently been recognized as a useful technique for pelvic fixation. The authors demonstrate two cases where S2AI fixation was indicated: one case was a sacral insufficiency fracture following a long-segment fusion in a patient with a transitional S-1 vertebra; the other case involved pseudarthrosis following lumbosacral fixation. S2AI screws offer rigid fixation, low profile, and allow easy connection to the lumbosacral rod. The authors describe and demonstrate the surgical technique and nuances for the S2AI screw in a case with transitional S-1 anatomy and in a case with normal S-1 anatomy. The video can be found here: https://youtu.be/Sj21lk13_aw . PMID:27364429

  13. Non-vascularized bone graft with herbert-type screw fixation for proximal pole scaphoid nonunion

    International Nuclear Information System (INIS)

    Since proximal pole fractures of the scaphoid are frequently overlooked, the poor vascularity in the proximal pole fragment often leads to nonunion. Vascularized bone grafts have been recently tested in cases with scaphoid proximal pole nonunion, but the indication for this treatment has not been well established. Alternatively, we have been treating such patients with a non-vascularized iliac bone graft and Herbert-type screw fixation with considerable success. The purpose of this investigation is to evaluate these cases retrospectively and clarify the surgical efficacy of our procedure. Between 1996 and 2009, 11 consecutive patients with proximal pole scaphoid nonunion were treated with a non-vascularized corticocancellous iliac bone graft and Herbert-type screw fixation. They were all male aged from 12 to 26 years. In two patients, avascular changes were recognized in the proximal pole in preoperative radiographs or MRI. Follow-up ranged from 12 to 76 months. Bone union was radiographically confirmed in all patients, who returned to their former activities without any complications. The period from operation to union ranged from 12 to 24 weeks. The mean Mayo modified wrist score was 76.4 points preoperatively and 91.4 points postoperatively, and was improved in all cases. A non-vascularized iliac bone graft with Herbert-type screw fixation obtained satisfactory clinical and radiographic results in cases with scaphoid proximal pole nonunion, regardless of the vascularity in the proximal fragment. (author)

  14. Combined Percutaneous Iliosacral Screw Fixation With Sacroplasty Using Resorbable Calcium Phosphate Cement for Osteoporotic Pelvic Fractures Requiring Surgery.

    Science.gov (United States)

    Collinge, Cory A; Crist, Brett D

    2016-06-01

    Osteoporotic sacral fractures, including acute and chronic insufficiency fractures, are increasing in frequency and present a number of management problem. Many of these patients are treated nonoperatively with relative immobility (eg, bedrest, wheelchair, or weight-bearing restrictions) and analgesics, which likely make the osteoporotic component worse. Surgery in this patient population may be desirable in some cases with the goals of improving mobility, relieving pain, and healing in an aligned position while minimizing deformity progression. However, internal fixation of the osteoporotic pelvis can be difficult. Large unicortical lag screws are the workhorse of posterior pelvic fixation, and yet fixation in cancellous bone corridors of an osteoporotic sacrum seems unlikely to achieve optimal fixation. As a result, the operative management and clinical results of these difficult injuries may not be uniformly successful. The authors present a technique for treating osteoporotic patients with a sacral fracture when operative treatment is indicated using percutaneous screw fixation combined with screw augmentation using a resorbable calcium phosphate bone substitute or "cement." The guide wire for a 7.3-mm or other large cannulated lag screw is fully inserted along the desired bony sacral corridor as is standard. The lag screw is then inserted over the wire to the depth where cement is desired. The guide wire is removed, and the aqueous calcium phosphate is injected through the screw's cannulation. For acute fractures, cement was applied to the areas distant to the fracture; whereas in insufficiency fractures, the cement was inserted along most of the screw path. The guide wire then can be reinserted and the lag screw fully inserted. The rationale for using these 2 modalities is their synergistic effect: the cannulated screw provides typical screw fixation and also a conduit for cement application. The cement augments the lag screw's purchase in osteoporotic bone

  15. Combining of small fragment screws and large fragment plates for open reduction and internal fixation of periprosthetic humeral fractures

    Directory of Open Access Journals (Sweden)

    Dominik Seybold

    2011-01-01

    Full Text Available Operative treatment of periprosthetic humeral fractures in elderly patients with osteoporotic bone requires a stable fixations technique. The combination of 3.5 cortical screws with washers in a 4.5 Arbeitsgemeinschaft fόr Osteosynthesefragen, Limited-contact dynamic compression plate or Locking plate, allows a stable periprosthetic fixation with the small 3.5 screws and 4.5 screws above and below the prosthesis, respectively. This combination is a cost-effective technique to treat periprosthetic humeral fractures.

  16. Internal fixation with headless compression screws and back buttress plate for treatment of old Hoffa fracture

    Directory of Open Access Journals (Sweden)

    Min Li

    2014-04-01

    Full Text Available Objective: To analyze the early clinical and radiographic outcomes of Hoffa fractures treated by a standard protocol of open reduction and internal fixation using headless compression screws combined with back buttress plate in a consecutive series of 8 Chinese patients. Methods: Open reduction and internal fixation was performed on all patients. The fractures were anatomically reduced and held temporarily by K-wire. If the ends of fractures were atrophic, autologous bone graft from the ipsilateral iliac crest was packed between the ends. Then the fracture fragments were fixed with AO 6.5 mm headless compression cannulated screws. At least two screws were used to provide rotational stability. One pre-contoured reconstruction plate was placed on the nonarticular surface posteromedially or posterolaterally as back buttress plate. Results: All the patients were followed up for at least 12 months (range 12-25 months. All fractures achieved anatomical reduction and healed clinically and radiographically. At recent follow-up, the mean flexion degree was 120.6° (range 110°-135° and the mean extension degree was 2.5° (range 0°-5°. The average visual analogue scale score was 1.6 points (range 0-3. Six patients were assessed as excellent and 2 as good according to the hospital for special surgery knee score system. There were no superficial or deep infections, or hardware breakages. No patient had giving way or locking of the knee, though some had intermittent pain and swelling after strenuous exercise. Injury mechanism had significant influence on the functional outcome (P=0.046.Conclusion: Headless compression screws combined with back buttress plate and/or autologous bone grafting to treat old Hoffa fracture is one of effective measures. It would be conducive to not only fracture healing but also early exercise and functional recovery. Key words: Fractures, bone; Fracture fixation, internal; Intra-articular fractures

  17. Alternative technique of cervical spinal stabilization employing lateral mass plate and screw and intra-articular spacer fixation

    OpenAIRE

    Atul Goel

    2013-01-01

    Aim: The author discusses an alternative technique of segmental cervical spinal fixation. Material and Methods: The subtleties of the technique are discussed on the basis of experience with 3 cases with a follow-up of between 30 and 36 months. Technique: The technique involves debridement of facetal articular cartilage, distraction of facets, jamming of ′Goel spacer′ into the articular cavity and fortification of the fixation by lateral mass plate and screw fixation. The ′double-insurance′ me...

  18. Radiostrontium clearance and bone formation in response to simulated internal screw fixation

    International Nuclear Information System (INIS)

    Changes in radiostrontium clearance (SrC) and bone formation (tetracycline labeling) were observed in the femurs of skeletally mature dogs following the various operative steps involved in bone screw fixation. Drilling, but not periosteal stripping, produced a small but statistically significant increase in SrC and endosteal bone formation in the distal third of the bone. Strontium clearance values equivalent to those produced by drilling alone were recorded after screw fixation at low or high torque (5 versus 20 inch pounds), as well as by the insertion of loosely fitting stainless steel implants. Bone formation (equals the percentage tetracycline-labeled trabecular bone surfaces) was increased by 30% when SrC values exceeded 3.5 ml/100 g bone/min, and the relationship was linear when SrC values ranged between 1.0 and 7.0 ml/100 g bone/min. The changes in SrC and bone formation one-week after bone screw application are primarily those associated with a response to local trauma caused by drilling

  19. Effects of Lateral Mass Screw Rod Fixation to the Stability of Cervical Spine after Laminectomy

    Science.gov (United States)

    Rosli, Ruwaida; Kashani, Jamal; Kadir, Mohammed Rafiq Abdul

    There are many cases of injury in the cervical spine due to degenerative disorder, trauma or instability. This condition may produce pressure on the spinal cord or on the nerve coming from the spine. The aim of this study was, to analyze the stabilization of the cervical spine after undergoing laminectomy via computational simulation. For that purpose, a three-dimensional finite element (FE) model for the multilevel cervical spine segment (C1-C7) was developed using computed tomography (CT) data. There are various decompression techniques that can be applied to overcome the injury. Usually, decompression procedures will create an unstable spine. Therefore, in these situations, the spine is often surgically restabilized by using fusion and instrumentation. In this study, a lateral mass screw-rod fixation was created to stabilize the cervical spine after laminectomy. Material properties of the titanium alloy were assigned on the implants. The requirements moments and boundary conditions were applied on simulated implanted bone. Result showed that the bone without implant has a higher flexion and extension angle in comparison to the bone with implant under applied 1Nm moment. The bone without implant has maximum stress distribution at the vertebrae and ligaments. However, the bone with implant has maximum stress distribution at the screws and rods. Overall, the lateral mass screw-rod fixation provides stability to the cervical spine after undergoing laminectomy.

  20. Internal fixation with headless compression screws and back buttress plate for treatment of old Hoffa fracture

    Institute of Scientific and Technical Information of China (English)

    Min Li; Tu Chongqi; Wang Guanglin; Fang Yue; Duan Hong; Liu Lei; Zhang Hui

    2014-01-01

    Objective:To analyze the early clinical and radiographic outcomes of Hoffa fractures treated by a standard protocol of open reduction and internal fixation using headless compression screws combined with back buttress plate in a consecutive series of 8 Chinese patients.Methods:Open reduction and internal fixation was performed on all patients.The fractures were anatomically reduced and held temporarily by K-wire.If the ends of fractures were atrophic,autologous bone graft from the ipsilateral iliac crest was packed between the ends.Then the fracture fragments were fixed with AO 6.5 mm headless compression cannulated screws.At least two screws were used to provide rotational stability.One pre-contoured reconstruction plate was placed on the nonarticular surface posteromedially or posterolaterally as back buttress plate.Results:All the patients were followed up for at least 12 months (range 12-25 months).All fractures achieved anatomical reduction and healed clinically and radiographically.At recent follow-up,the mean flexion degree was 120.6° (range 110°-135°) and the mean extension degree was 2.5° (range 0°-5°).The average visual analogue scale score was 1.6 points (range 0-3).Six patients were assessed as excellent and 2 as good according to the hospital for special surgery knee score system.There were no superficial or deep infections,or hardware breakages.No patient had giving way or locking of the knee,though some had intermittent pain and swelling after strenuous exercise.Injury mechanism had significant influence on the functional outcome (P=0.046).Conclusion:Headless compression screws combined with back buttress plate and/or autologous bone grafting to treat old Hoffa fracture is one of effective measures.It would be conducive to not only fracture healing but also early exercise and functional recovery.

  1. Anterior transarticular screw fixation for atlantoaxial arthrodesis: A report of two cases

    OpenAIRE

    Carrier, C. S.; A A Sama; Girardi, F. P.; Lebl, D. R.

    2013-01-01

    The sequelae of atlantoaxial instability (AAI) range from axial neck pain to life-threatening neurologic injury. Instrumentation and fusion of the C1-2 joint is often indicated in the setting of clinical or biomechanical instability. This is the first clinical report of anterior Smith-Robinson C1-2 transarticular screw (TAS) fixation for AAI. The first patient presented with ischemic brain tissue secondary to post-traumatic C1-2 segment instability from a MVC 7 years prior to presentation. Th...

  2. Efficacy of open reduction and internal fixation with a miniplate and hollow screw in the treatment of Lisfranc injury

    OpenAIRE

    Li Baoliang; Zhao Wenbo; Liu Lei; Huang Fuguo; Wang Guanglin; Fang Yue

    2015-01-01

    Purpose: To investigate efficacy of open reduction and internal fixation with the miniplate and hollow screw in the treatment of Lisfranc injury. Methods: Ten cases of Lisfranc injury treated by open reduction, miniplate and hollow screw in our hospital were retrospectively analyzed. There were 6 males and 4 females with age ranging from 25 to 45 years (mean 32 years). Among them, one case was classified as Type A, six Type B and three Type C. Injury mechanism included road traffic acciden...

  3. Computed tomography- and fluoroscopy-guided percutaneous screw fixation of low-grade isthmic spondylolisthesis in adults: a new technique

    Energy Technology Data Exchange (ETDEWEB)

    Amoretti, Nicolas; Huwart, Laurent; Browaeys, Patrick; Nouri, Yasir; Ibba, Caroline [Hopital Archet 2, Centre Hospitalo-Universitaire de Nice, Department of Radiology, Nice (France); Hauger, Olivier [Hopital Pellegrin, Centre Hospitalo-Universitaire de Bordeaux, Department of Radiology, Bordeaux (France); Marcy, Pierre-Yves [Antoine Lacassagne Cancer Research Institute, Department of Radiology, Nice (France); Boileau, Pascal [Hopital Archet 2, Centre Hospitalo-Universitaire de Nice, Department of Orthopedic Surgery, Nice (France)

    2012-12-15

    To evaluate the feasibility of computed tomography (CT)- and fluoroscopy-guided percutaneous screw fixation for the treatment of low-grade isthmic spondylolisthesis in adults. Ten consecutive adult patients (four men and six women; mean age: 57.1 [range, 44-78 years]) were prospectively treated by percutaneous screw fixation for low-grade (six grade 1 and four grade 2) isthmic spondylolisthesis of L5. For each patient, two 4.0-mm Asnis III cannulated screws were placed to fix the pars interarticularis defects. All procedures were performed under local anaesthesia by using CT and fluoroscopy guidance. Post-operative outcome was assessed using the visual analogue scale and Oswestry Disability Index (ODI) scores. The procedure time ranged from 45 to 60 min. The mean screw length was 27 mm (range, 24-32 mm). The VAS and ODI measurements {+-} SD decreased from 7.8 {+-} 0.9 preoperatively to 1.5 {+-} 1.1 at the last 2-year follow-up, and from 62.3 {+-} 17.2 to 15.1 {+-} 6.0, respectively (P < 0.001 in both cases). Neither slip progression nor screw failure was noted. This feasibility study showed that CT- and fluoroscopy-guided percutaneous screw fixation could be a rapid, safe and effective method of treating low-grade isthmic spondylolisthesis. (orig.)

  4. Computed tomography- and fluoroscopy-guided percutaneous screw fixation of low-grade isthmic spondylolisthesis in adults: a new technique

    International Nuclear Information System (INIS)

    To evaluate the feasibility of computed tomography (CT)- and fluoroscopy-guided percutaneous screw fixation for the treatment of low-grade isthmic spondylolisthesis in adults. Ten consecutive adult patients (four men and six women; mean age: 57.1 [range, 44-78 years]) were prospectively treated by percutaneous screw fixation for low-grade (six grade 1 and four grade 2) isthmic spondylolisthesis of L5. For each patient, two 4.0-mm Asnis III cannulated screws were placed to fix the pars interarticularis defects. All procedures were performed under local anaesthesia by using CT and fluoroscopy guidance. Post-operative outcome was assessed using the visual analogue scale and Oswestry Disability Index (ODI) scores. The procedure time ranged from 45 to 60 min. The mean screw length was 27 mm (range, 24-32 mm). The VAS and ODI measurements ± SD decreased from 7.8 ± 0.9 preoperatively to 1.5 ± 1.1 at the last 2-year follow-up, and from 62.3 ± 17.2 to 15.1 ± 6.0, respectively (P < 0.001 in both cases). Neither slip progression nor screw failure was noted. This feasibility study showed that CT- and fluoroscopy-guided percutaneous screw fixation could be a rapid, safe and effective method of treating low-grade isthmic spondylolisthesis. (orig.)

  5. CT analysis of the axis for transarticular screw fixation of rheumatoid atlantoaxial instability

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Sung Soo; Lee, Chong Suh; Kang, Chang Seok [Sungkyunkwan University School of Medicine, Department of Orthopedic Surgery, Samsung Medical Center, Seoul (Korea); Chung, Hye Won [Sungkyunkwan University School of Medicine, Department of Radiology, Samsung Medical Center, Seoul (Korea)

    2006-09-15

    To investigate the morphological characteristics of the axis of rheumatoid arthritis (RA) patients with atlantoaxial instability and to determine, by means of sagittal reconstructed computed tomography (CT), the suitability for atlantoaxial transarticular screw fixation. Twenty-seven patients, who had undergone reconstructed cervical spine CT scanning preoperatively and posterior atlantoaxial arthrodesis for atlantoaxial instability, were identified from a database for inclusion in this study. The isthmus height and internal height of the lateral mass of the axis were measured using digital imaging software. The mean isthmus height and internal height of the lateral mass of the axis in RA patients (n=14) were significantly lower than in non-RA patients (n=13) (P<0.01). A high-riding vertebral artery (VA) was present in 54% (15 joints, 9 patients) of the 28 atlantoaxial joints in the RA group and in 12% (3 joints, 2 patients) of the 26 atlantoaxial joints in the non-RA group (P<0.01). In RA patients, the axis showed more extensive thinning of the isthmus and lateral mass than in non-RA patients. A precise preoperative evaluation of screw trajectory using reconstruction CT imaging may be useful in atlantoaxial transarticular fixation, particularly for RA patients with atlantoaxial instability. (orig.)

  6. Efficacy of Pedicle Screw Fixation in Unstable Upper and Middle Thoracic Spine Fractures

    Science.gov (United States)

    Ghasemi, Amir Abbas; Ashoori, Soudabeh

    2016-01-01

    Background: Treatment of unstable upper and middle thoracic spine fractures remains controversial. There is no consensus regarding optimal treatment. Objectives: In this study, we evaluated the efficacy of pedicular screw in the management of middle thoracic spine fractures to correct kyphosis and anterolisthesis and improve neurologic condition of patients. Patients and Methods: Twenty-five patients with unstable T1-T10 fractures treated with pedicle screw fixation technique were studied. Neurologic situation, preoperative and postoperative radiographs were evaluated. Radiographic measurements included kyphotic deformity and anterolisthesis. An American Spinal Injury Association (ASIA) scale was used for neurologic classification of the patients. Results: From a total of 25 patients, 21 cases were male and 4 were female. The mean age of the patients was 35.40 ± 14.39 years. The mean degree of kyphosis improved from 27.04 ± 7.33 degrees preoperatively to 15.96 ± 5.76 degrees at final follow-up. The mean of anterolisthesis improved from 6.44 ± 4.93 mm to 0.96 ± 0.36 mm at final follow-up. Kyphosis (P = 0.0001), anterolisthesis (P = 0.0001) and neurological state (P = 0.01) improved significantly after operation. No cases of hardware failure, neurological deterioration and loss of correction were reported. Conclusions: Application of pedicular screw in unstable upper and middle thoracic spine fractures is an effective method that can correct kyphotic deformity and anterolisthesis and improve neurologic deficit. PMID:27218058

  7. Treatment of neuromuscular scoliosis with posterior-only pedicle screw fixation

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    Fernandez Harry M

    2008-06-01

    Full Text Available Abstract Background To determine whether posterior-only approach using pedicle screws in neuromuscular scoliosis population adequately addresses the correction of scoliosis and maintains the correction over time. Methods Between 2003 and 2006, 26 consecutive patients (7 cerebral palsy, 10 Duchenne muscular dystrophy, 5 spinal muscular atrophy and 4 others with neuromuscular scoliosis underwent posterior pedicle screw fixation for the deformity. Preoperative, immediate postoperative and final follow-up Cobb's angle and pelvic obliquity were analyzed on radiographs. The average age of the patients was 17.5 years (range, 8–44 years and the average follow-up was 25 months (18–52 months. Results Average Cobb's angle was 78.53° before surgery, 30.70° after surgery (60.9% correction, and 33.06° at final follow-up (57.9% correction showing significant correction (p Conclusion Results indicate that in patients with neuromuscular scoliosis, acceptable amounts of curve correction can be achieved and maintained with posterior-only pedicle screw instrumentation without anterior release procedure.

  8. Efficacy of radial styloid targeting screws in volar plate fixation of intra-articular distal radial fractures: a biomechanical study in a cadaver fracture model

    OpenAIRE

    Yamashita Toshihiko; Kamiya Tomoaki; Wada Takuro; Ozasa Yasuhiro; Iba Kousuke; Aoki Mitsuhiro

    2010-01-01

    Abstract Background The locking screws target the radial styloid, theoretically provide greater stability against radial styloid fragment. However, it is unknown whether the radial styloid locking screws increased the stability of the volar plating system fixation along the entire distal radius or not. In this study, we evaluated the stability of the volar plating system fixation with or without the radial styloid screws using a biomechanical study in a cadaver fracture model. Methods Six mat...

  9. Biomechanical Comparison Between Bashti Bone Plug Technique and Biodegradable Screw for Fixation of Grafts in Ligament surgery

    OpenAIRE

    Kaveh Bashti; Mohammad Naghi Tahmasebi; Hasan Kaseb; Farzam Farahmand; Mohammad Akbar; Amir Mobini

    2015-01-01

      Background: Ligament reconstruction is a common procedure in orthopedic surgery. Although several popular techniques are currently in use, new methods are proposed for secure fixation of the tendon graft into the bone tunnel. Purposes: We sought to introduce our new technique of Bashti bone plug for fixation of soft tissue graft in anterior cruciate ligament (ACL) reconstruction and to compare its biomechanical features with conventional absorbable interference screw technique in a bovine ...

  10. Alternative technique of cervical spinal stabilization employing lateral mass plate and screw and intra-articular spacer fixation

    Directory of Open Access Journals (Sweden)

    Atul Goel

    2013-01-01

    Full Text Available Aim: The author discusses an alternative technique of segmental cervical spinal fixation. Material and Methods: The subtleties of the technique are discussed on the basis of experience with 3 cases with a follow-up of between 30 and 36 months. Technique: The technique involves debridement of facetal articular cartilage, distraction of facets, jamming of ′Goel spacer′ into the articular cavity and fortification of the fixation by lateral mass plate and screw fixation. The ′double-insurance′ method of fixation is safe for vertebral artery, nerve roots and spinal neural structures and the fixation is strong. Conclusions: The discussed technique is safe and provides a strong fixation and a ground for ultimate arthrodesis.

  11. Biomechanical Comparison Between Bashti Bone Plug Technique and Biodegradable Screw for Fixation of Grafts in Ligament surgery

    Directory of Open Access Journals (Sweden)

    Kaveh Bashti

    2015-01-01

    Full Text Available   Background: Ligament reconstruction is a common procedure in orthopedic surgery. Although several popular techniques are currently in use, new methods are proposed for secure fixation of the tendon graft into the bone tunnel. Purposes: We sought to introduce our new technique of Bashti bone plug for fixation of soft tissue graft in anterior cruciate ligament (ACL reconstruction and to compare its biomechanical features with conventional absorbable interference screw technique in a bovine model. Methods: Twenty pairs of bovine knees were harvested after death. Soft tissue was removed and the Achilles tendon was harvested to be used as an ACL graft. It was secured into the bone tunnel on the tibial side via two different methods: Bashti Bone Plug technique and conventional screw method. Biomechanical strength was measured using 200 N and 300 N cyclic loading on the graft. Pull out strength was also tested until the graft fails. Results: No graft failure was observed after 200 N and 300 N cyclic loading in either fixation methods. When testing for pull out failure, 21 tendons (53% were torn and 19 tendons (48% slipped out. No fixation failure occurred, which did not reveal a significant difference between the bone plug or interference screw group (P=0.11. The mean pull out force until failure of the graft was 496±66 N in the screw group and 503±67 N in the bone plug group (P=0.76. Conclusions: Our suggested fixation technique of Bashti bone plug is a native, cheap, and feasible method that provides comparable biomechanical strength with interference screw when soft tissue fixation was attempted in bovine model.

  12. Anterior transarticular screw fixation for atlantoaxial arthrodesis: A report of two cases

    Directory of Open Access Journals (Sweden)

    C S Carrier

    2013-01-01

    Full Text Available The sequelae of atlantoaxial instability (AAI range from axial neck pain to life-threatening neurologic injury. Instrumentation and fusion of the C1-2 joint is often indicated in the setting of clinical or biomechanical instability. This is the first clinical report of anterior Smith-Robinson C1-2 transarticular screw (TAS fixation for AAI. The first patient presented with ischemic brain tissue secondary to post-traumatic C1-2 segment instability from a MVC 7 years prior to presentation. The second patient presented with a 3 year history of persistent right-sided neck and upper scalp pain. Both were treated with transarticular C1-2 fusion through decortication of the atlantoaxial facet joints and TAS fixation via the anterior Smith-Robinson approach. At 16 months follow-up, the first patient maintained painless range of motion of the cervical spine and denied sensorimotor deficits. The second patient reported 90% improvement in her pre-operative symptoms of neck pain and paresthesia. Anterior Smith-Robinson C1-2 TAS fixation provides a useful alternative to the posterior Goel and Magerl techniques for C1-2 stabilization and fusion.

  13. Percutaneous Cement-Augmented Screws Fixation in the Fractures of the Aging Spine: Is It the Solution?

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    Sébastien Pesenti

    2014-01-01

    Full Text Available Introduction. Management of elderly patients with thoracolumbar fractures is still challenging due to frequent osteoporosis and risk of screws pull-out. The aim of this study was to evaluate results of a percutaneous-only procedure to treat these fragile patients using cement-augmented screws. Methods. 12 patients diagnosed with a thoracolumbar fracture associated with an important loss of bone stock were included in this prospective study. Surgical procedure included systematically a percutaneous osteosynthesis using cemented fenestrated screws. When necessary, additional anterior support was performed using a kyphoplasty procedure. Clinical and radiographic evaluations were performed using CT scan. Results. On the whole series, 15 fractures were diagnosed and 96 cemented screws were inserted. The difference between the pre- and postoperative vertebral kyphosis was statistically significant (12.9° versus 4.4°, P=0.0006. No extrapedicular screw was reported and one patient was diagnosed with a cement-related pulmonary embolism. During follow-up period, no infectious complications, implant failures, or pull-out screws were noticed. Discussion. Aging spine is becoming an increasing public health issue. Management of these patients requires specific attention due to the augmented risk of complications. Using percutaneous-only screws fixation with cemented screw provides satisfactory results. A rigorous technique is mandatory in order to achieve best outcomes.

  14. Changes in the computed tomography (pixel) value of mandibular ramus bone and fixation screws after sagittal split ramus osteotomy.

    Science.gov (United States)

    Ueki, K; Moroi, A; Iguchi, R; Kosaka, A; Ikawa, H; Yoshizawa, K

    2015-11-01

    The purpose of this retrospective study was to evaluate the changes in computed tomography (CT) values of ramus bone and screws after sagittal split ramus osteotomy (SSRO) setback surgery. The subjects were 64 patients (128 sides) who underwent bilateral SSRO setback surgery. They were divided into six groups according to the fixation plate type used and the use or not of self-setting α-tricalcium phosphate (Biopex): group 1: titanium plate and screws; group 2: titanium plate and screws with Biopex; group 3: poly-l-lactic acid (PLLA) plate and screws; group 4: PLLA plate and screws with Biopex; group 5: uncalcined and unsintered hydroxyapatite particles and poly-l-lactic acid (uHA/PLLA) plate and screws; group 6: PLLA/uHA plate and screws with Biopex. CT values (pixel values) of the lateral cortex, medial cortex, osteotomy site, and screws were measured preoperatively, immediately after surgery, and 1 year postoperatively using horizontal CT images at the mandibular foramen taken parallel to the Frankfort horizontal plane. There were significant differences in the time-course change of pixel values for the lateral cortex (Pmaterial may affect bone quality during the process of bone healing after SSRO. PMID:26139563

  15. Accuracy and complications of posterior C2 screw fixation using intraoperative three-dimensional fluoroscopy-based navigation

    Institute of Scientific and Technical Information of China (English)

    Tao Xiaohui; Tian Wei; Liu Bo; Li Qin; Zhang Guilin

    2014-01-01

    Background The peculiar and highly variable C2 anatomy can make screw fixation more challenging and prone to potential vertebral artery or neurologic injury.Conventional C-arm fluoroscopy has several drawbacks.The aim of this research was to evaluate the accuracy of posterior C2 screw fixation using intraoperative three-dimensional fluoroscopybased navigation (ITFN) and assess the perioperative complication rate related to screw placement.Methods A retrospective review identified patients who underwent operative management with C2 instruments using ITFN at our hospital between January 2006 and December 2012.Clinical data were obtained from medical records and final screw positions were graded according to a modified classification of Gertzbein and Robbins.Grade A and B screws were considered well positioned.Results The study included 99 patients (53 males and 46 females) who underwent posterior C2 screw fixation using ITFN.The mean Japan Orthopedic Association score improved from (6.7±1.9) points before surgery to (12.5±2.7) points at 6-month follow-up (z=+8.628,P <0.01).The mean visual analogue scale improved from (4.1±1.2) points before surgery to (0.7±0.9) points at 6-month follow-up,with an improvement of 83.7% (z=8.638,P < 0.01).Of the 196 screws analyzed using computed tomography and chart review,126 transarticular,64 pedicle,and 6 pars screws were placed with 82.5% (104/126),89.1% (57/64),and 100% (6/6) accuracy (grade A),respectively; 98.5% (193/196) of screws were grade A or B (grade C,1.5% (3/196)),and no neurologic injuries occurred.In normal C2 cases,93 transarticulars and 47 pedicles were placed with high accuracy rates of 90.3% (84/93) and 93.6% (44/47) (grade A),respectively.However,in cases with C2 deformity,33 transarticular,17 pedicle,and 6 pars screws were placed with only 60.6% (20/33),76.5% (13/17),and 100% (6/6) accuracy (grade A),respectively.Conclusion ITFN is a safe,accurate,and effective tool for posterior C2

  16. Pedicle screw fixation combined with intervertebral bone grafting for the treatment of thoracolumbar fracture: a report of 24 cases

    Directory of Open Access Journals (Sweden)

    Chuan-lin DU

    2014-01-01

    Full Text Available Objective To explore the clinical effect of pedicle screw fixation combined with intervertebral bone grafting for the treatment of thoracolumbar fractures. Methods The clinical data of 24 cases of unstable and/or bursting thoracolumbar fractures treated with pedicle screw fixation and intervertebral bone grafting from July 2007 to July 2010 were analyzed retrospectively. The 24 patients (18 males and 6 females were aged from 24 to 61 years (mean 31.5 years, in whom 8 with fracture of T12, 9 of L1, 5 of L2, and 2 of L3 vertebral fracture. According to Denis classification, in 8 patients it was compression fracture, and in 16 patients it was burst fracture. According to American Spinal Injury Association (ASIA criteria, 2 patients were classified as grade C, 2 as grade D and 20 as grade E. All of the 24 patients received pedicle screw fixation combined with intervertebral bone grafting to reduce and fix the thoracolumbar fractures using pedicle screw-rod system, and 4 of them received posterior decompression. Results Twenty-two patients were followed-up from 12 to 24 months (mean 18 months. No obvious loss of vertebral height or posterior protuberance was found. There was no evidence of screw loosening or breakage, neither overdistraction of intervertebral space among 22 patients. The Cobb angle was corrected from 15-44 degrees (32.3±7.6 degrees, preoperatively to 0-9.6 degrees (6.6±2.4 degrees as observed at the time of last follow-up. Conclusion Pedicle screw fixation combined with intervertebral bone grafting could reconstruct the mechanical structure of anterior and middle spinal columns, obtain effective intervertebral height and bone union, and long-term spine stability. DOI: 10.11855/j.issn.0577-7402.2013.12.11

  17. Biomechanical effects of polyaxial pedicle screw fixation on the lumbosacral segments with an anterior interbody cage support

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    Chen Hsiang-Ho

    2007-03-01

    Full Text Available Abstract Background Lumbosacral fusion is a relatively common procedure that is used in the management of an unstable spine. The anterior interbody cage has been involved to enhance the stability of a pedicle screw construct used at the lumbosacral junction. Biomechanical differences between polyaxial and monoaxial pedicle screws linked with various rod contours were investigated to analyze the respective effects on overall construct stiffness, cage strain, rod strain, and contact ratios at the vertebra-cage junction. Methods A synthetic model composed of two ultrahigh molecular weight polyethylene blocks was used with four titanium pedicle screws (two in each block and two rods fixation to build the spinal construct along with an anterior interbody cage support. For each pair of the construct fixed with polyaxial or monoaxial screws, the linked rods were set at four configurations to simulate 0°, 7°, 14°, and 21° lordosis on the sagittal plane, and a compressive load of 300 N was applied. Strain gauges were attached to the posterior surface of the cage and to the central area of the left connecting rod. Also, the contact area between the block and the cage was measured using prescale Fuji super low pressure film for compression, flexion, lateral bending and torsion tests. Results Our main findings in the experiments with an anterior interbody cage support are as follows: 1 large segmental lordosis can decrease the stiffness of monoaxial pedicle screws constructs; 2 polyaxial screws rather than monoaxial screws combined with the cage fixation provide higher compression and flexion stiffness in 21° segmental lordosis; 3 polyaxial screws enhance the contact surface of the cage in 21° segmental lordosis. Conclusion Polyaxial screws system used in conjunction with anterior cage support yields higher contact ratio, compression and flexion stiffness of spinal constructs than monoaxial screws system does in the same model when the spinal segment

  18. Bone cement enhanced pedicle screw fixation combined with vertebroplasty for elderly patients with malignant spinal tumors

    Institute of Scientific and Technical Information of China (English)

    TAN Jiang-wei; SHEN Bing-hua; DU Wei; LIU Jiang-qing; LU Shi-qiao

    2013-01-01

    Background Older patients with malignant spinal tumors are difficult to treat because they have many co-morbidities including osteoporosis.The purpose of this research is to discuss the technique and clinical outcome of bone cement enhanced pedicle screw fixation combined with vertebroplasty (the Sandwich Procedure) for elderly patients with severe osteoporosis and malignant spinal tumors.Methods This study includes 28 consecutive elderly patients with malignant thoracic or lumbar spinal tumors.There were nine patients with myelomas,and 19 patients with metastatic bone tumors.The Sandwich Procedure began with curettage of the tumor and a vertebroplasty with bone cement (polymethyl methacrylate,PMMA),followed by PMMA enhanced pedicle screw fixation.Patients were evaluated with the visual analogue scale (VAS),oswestry disability index (ODI),American Spinal Cord Injury Association (ASIA) neurological function classification,and the radiographic degree of kyphosis (Cobb angle).Data were analyzed using paired t-test to compare the pre-and post-operative values.The complications,local recurrences,and the survival status were also recorded.Results There was no operative mortality,and the mean operative time was 210 minutes (range 150-250 minutes).The average blood loss was 1550 ml (range 650-3300 ml).The average amount of cement for vertebroplasty was 3.6 ml (range 3-5 ml).The VAS,ODI,and ASIA scores were significantly improved after surgery (P <0.05).However,we found no differences between the pre and post-operative Cobb angles.The shortest survival time was 3 months,and we found no evidence of local recurrence in this group of patients.Conclusion The Sandwich Procedure is a safe operation and provides symptomatic relief in these difficult patients,permitting further treatment with chemotherapy or radiotherapy.

  19. Radiological outcome of transpedicular screws fixation in the management of thoracolumbar spine injury

    International Nuclear Information System (INIS)

    Traumatic fracture of the spine is a serious neurosurgical condition that has serious impact on the patient's quality of life. Thoracolumbar junction is the most common site of spinal injuries. The aims of management of thoracolumbar spinal fractures are to restore vertebral column stability, and to obtain spinal canal decompression. This ultimately leads to early mobilization of the patients. This study was conducted to compare preoperative and post-operative vertebral height, kyphotic angle and sagittal index in patients treated with pedicle screws and rods in thoracolumbar spine fractures. Methods: This cross-sectional study was conducted in the department of Neurosurgery, Hayatabad Medical Complex, Peshawar from 1st February 2010 to 31st July 2011. A total 161 patients with unstable thoracolumber spine fracture were included in this study. In these patients fixation was done through transpedicle screws with rods. Anteroposterior and lateral views X-rays of thoraco-lumbar spine were done pre and post operatively. Results: Out of 161 patients, 109 (67.7%) were males and 52 (32.3%) females. The age of patients ranged from 20 to 70 years (mean 42.2 years) with 71 (44.1%) in the age range of 31-40 years. Preoperative average vertebral height was 9.4194 mm while postoperative average was 19.642 mm. The mean kyphosis was 23.06 degree preoperatively. Immediately after surgery the average correction of kyphosis was 9.45 degree. The pre-operative average sagittal index was 19.38 degree, which was reduced to an average 5.41 degree post operatively. Conclusions: Transpedicular fixation for unstable thoraco-lumbar spinal fractures achieves a stable fracture segment with improvement of vertebral height, kyphotic angle and sagittal index. Hence, preventing the secondary spinal deformities. (author)

  20. Determination of the most appropriate stress distribution by Finite Element Analysis in fixation with resorbable screws after Bilateral Sagittal Split Ramus Osteotomy surgery

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    Sarkarat F.

    2009-12-01

    Full Text Available "nBackground and Aim: Due to the complications associated with fixation by Titanium screws and plates in Bilateral Sagittal Split Ramus Osteotomy (BSSRO surgery, the use of resorbable polymers has been increasingly recommended. Since there are not enough studies on this issue, this study aimed to assess the most appropriate stress distribution in fixation with resorbable screws after BSSRO surgery by Fnite Element Analysis (FEA."nMaterials and Methods: This experimental study was performed on simulated human mandible using Ansys and Catia softwares. The osteotomy line was applied to the simulated model and experimental loads of 75, 135 and 600 N were respectively exerted according to the natural direction of occlusal force. The distribution pattern of stress was assessed and compared for fixation with one resorbable screw, two resorbable screws in vertical pattern, two resorbable screws in horizontal pattern, three resorbable screws in L pattern and three resorbable screws in inverted backward L pattern using Ansys software."nResults: Among the four simulated fixations, L pattern showed the highest primary stability. Two screws in vertical pattern were also associated with sufficient primary stability and less trauma and cost for patients. One screw did not provide enough stability under 600 N."nConclusion: Polymer-based resorbable screws (polyglycolic acid and D, L polylactide acid provided satisfactory primary stability in BSSRO surgery.

  1. Study on pedicle screw fixation of cervical spine assisted CT-based navigation system compared with the individual cervical peddle screws placement technique

    International Nuclear Information System (INIS)

    Objective: To explore a safe and effective method for placing the cervical pedicle screws. Methods: There were ten adult cadaver specimens of cervica spine (C1-C7) with intact structures including ligament and perivertebral muscles. The spiral computed tomography scan (Elscint CT Twin flash) at the section of 1 mm and three-dimensional reconstruction of all 10 cervical specimens were taken. By CT scan, the parameters of the cervical pedicles were measure,Then taking randomly 5 cervical specimens, according to the CT measurements, an appropriate screw was inserted into pedicle individually. In the other 5 human cadaver cervical vertebraes, Φ3.5 mm screws were inserted into the C2-C7 pedicles by assisted by CT-based navigation system. Cortical integrity of every sample was examined by anatomic dissection, the spiral computed tomography scan and arrows,and coronal reconstruction. Results: Sixty screws was inserted into pedicle individually, and the achievement ratio was 90%, the perfectness ratio was 75%, 60 screws was placed into pedicle assisted by CT-based navigation system, and the achievement ratio was 96.6%, the perfectness ratio was 90%. By chi-square test for statistical analysis, there were no statistical significance between the accuracy rate of two methods(P>0.05). However there was statistical significance between the perfectness ratio between two methods(P<0.05). Conclusion: Compared with the individual cervical peddle screws placement technique, the perfectness ratio of pedicle screw fixation of cervical spine assisted by CT-based navigation system is higher, but there are no significant difference in accuracy. (authors)

  2. Medial pelvic migration of the lag screw in a short gamma nail after hip fracture fixation: a case report and review of the literature

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    Li Xinning

    2010-08-01

    Full Text Available Abstract Hip fractures are a common injury among the elderly. Internal fixation with an intramedullary (IM system has gained popularity for the treatment of intertrochanteric femur fractures. Multiple complications associated with IM fracture fixation have been described, however, we report a rare complication of medial pelvic migration of the lag screw of a short IM nail in a stable construct ten weeks post surgery. The patient was subsequently treated with Lag Screw removal and revision surgery with a shorter Lag Screw and an accessory cannulated screw acting as a de-rotational device. The patient did well with the revision surgery and was able to return to full activities.

  3. Fiber-matrix interface studies on bioabsorbable composite materials for internal fixation of bone fractures. II. A new method using laser scanning confocal microscopy.

    Science.gov (United States)

    Slivka, M A; Chu, C C

    1997-12-01

    In this study, a new visual characterization method was developed using laser scanning confocal microscopy (LSCM) to study morphologic properties, particularly at the fiber-matrix interface, by optical sectioning of bioabsorbable single-fiber composites. The interface gap width (IGW) between the fiber and matrix, and the changes in IGW after in vitro hydrolysis, named the gap rate (Rg), were measured from images obtained using the LSCM. Higher values for IGW and Rg showed faster degradation of the fiber-matrix interface. These parameters were used to investigate the effects of strain, wicking, different reinforcing fibers, and gamma-irradiation on the fiber-matrix interface morphology. The component materials used were nonbioabsorbable AS4 carbon (C) fibers, bioabsorbable calcium phosphate (CaP), poly(glycolic acid) (PGA), and chitin fibers, and bioabsorbable poly(L-lactic acid) (PLLA) matrix. The application of strain on CaP/PLLA composites increased the IGW up to about 15%, after which there was no change up to 25%. The Rg for CaP/PLLA composites with the fiber ends exposed in vitro (permitting wicking) was greater than for CaP/PLLA with the fiber ends embedded completely within the matrix (preventing wicking). Open-end C/PLLA composites had the slowest rate of interface degradation in vitro, followed by chitin/PLLA, PGA/PLLA, and CaP/PLLA. The exposure of closed-end CaP/PLLA composites to 4 Mrad of gamma-irradiation, in air at room temperature or in vaccuum at 77K, accelerated the rate of interface degradation in vitro. In conclusion, an effective new visual characterization method was developed using LSCM, and it was used to show that (a) moderate strain could accelerate the degradation of the interface, (b) fiber-matrix interface wicking could accelerate the rate of degradation of the interface, (c) the rate of interface degradation depends on the type of fiber used, and (d) gamma-irradiation could accelerate the rate of interface degradation. Furthermore, the

  4. Evaluation of a prototype correction algorithm to reduce metal artefacts in flat detector computed tomography of scaphoid fixation screws

    Energy Technology Data Exchange (ETDEWEB)

    Filli, Lukas; Finkenstaedt, Tim; Andreisek, Gustav; Guggenberger, Roman [University Hospital of Zurich, Department of Diagnostic and Interventional Radiology, Zurich (Switzerland); Marcon, Magda [University Hospital of Zurich, Department of Diagnostic and Interventional Radiology, Zurich (Switzerland); University of Udine, Institute of Diagnostic Radiology, Department of Medical and Biological Sciences, Udine (Italy); Scholz, Bernhard [Imaging and Therapy Division, Siemens AG, Healthcare Sector, Forchheim (Germany); Calcagni, Maurizio [University Hospital of Zurich, Division of Plastic Surgery and Hand Surgery, Zurich (Switzerland)

    2014-12-15

    The aim of this study was to evaluate a prototype correction algorithm to reduce metal artefacts in flat detector computed tomography (FDCT) of scaphoid fixation screws. FDCT has gained interest in imaging small anatomic structures of the appendicular skeleton. Angiographic C-arm systems with flat detectors allow fluoroscopy and FDCT imaging in a one-stop procedure emphasizing their role as an ideal intraoperative imaging tool. However, FDCT imaging can be significantly impaired by artefacts induced by fixation screws. Following ethical board approval, commercially available scaphoid fixation screws were inserted into six cadaveric specimens in order to fix artificially induced scaphoid fractures. FDCT images corrected with the algorithm were compared to uncorrected images both quantitatively and qualitatively by two independent radiologists in terms of artefacts, screw contour, fracture line visibility, bone visibility, and soft tissue definition. Normal distribution of variables was evaluated using the Kolmogorov-Smirnov test. In case of normal distribution, quantitative variables were compared using paired Student's t tests. The Wilcoxon signed-rank test was used for quantitative variables without normal distribution and all qualitative variables. A p value of < 0.05 was considered to indicate statistically significant differences. Metal artefacts were significantly reduced by the correction algorithm (p < 0.001), and the fracture line was more clearly defined (p < 0.01). The inter-observer reliability was ''almost perfect'' (intra-class correlation coefficient 0.85, p < 0.001). The prototype correction algorithm in FDCT for metal artefacts induced by scaphoid fixation screws may facilitate intra- and postoperative follow-up imaging. (orig.)

  5. Evaluation of a prototype correction algorithm to reduce metal artefacts in flat detector computed tomography of scaphoid fixation screws

    International Nuclear Information System (INIS)

    The aim of this study was to evaluate a prototype correction algorithm to reduce metal artefacts in flat detector computed tomography (FDCT) of scaphoid fixation screws. FDCT has gained interest in imaging small anatomic structures of the appendicular skeleton. Angiographic C-arm systems with flat detectors allow fluoroscopy and FDCT imaging in a one-stop procedure emphasizing their role as an ideal intraoperative imaging tool. However, FDCT imaging can be significantly impaired by artefacts induced by fixation screws. Following ethical board approval, commercially available scaphoid fixation screws were inserted into six cadaveric specimens in order to fix artificially induced scaphoid fractures. FDCT images corrected with the algorithm were compared to uncorrected images both quantitatively and qualitatively by two independent radiologists in terms of artefacts, screw contour, fracture line visibility, bone visibility, and soft tissue definition. Normal distribution of variables was evaluated using the Kolmogorov-Smirnov test. In case of normal distribution, quantitative variables were compared using paired Student's t tests. The Wilcoxon signed-rank test was used for quantitative variables without normal distribution and all qualitative variables. A p value of < 0.05 was considered to indicate statistically significant differences. Metal artefacts were significantly reduced by the correction algorithm (p < 0.001), and the fracture line was more clearly defined (p < 0.01). The inter-observer reliability was ''almost perfect'' (intra-class correlation coefficient 0.85, p < 0.001). The prototype correction algorithm in FDCT for metal artefacts induced by scaphoid fixation screws may facilitate intra- and postoperative follow-up imaging. (orig.)

  6. Screw fixation to the posterior cortical shell does not influence peak torque and pullout in anterior cervical plating

    OpenAIRE

    Pitzen, T.; Barbier, D.; Tintinger, F.; Steudel, W; Strowitzki, M.

    2002-01-01

    There is no consensus over whether screw fixation for anterior cervical plating should include the posterior cortical shell of the vertebral bodies or not. Thus, the purpose of this study was to investigate the function of the posterior cortical shell with respect to maximal screw torque and pullout force. Twenty-four fresh frozen human cervical vertebrae coming from six spinal segments C4–C7 were used. They were scanned for bone mineral density (BMD) and then assigned to two groups with comp...

  7. A meta-analysis of unilateral versus bilateral pedicle screw fixation in minimally invasive lumbar interbody fusion.

    Directory of Open Access Journals (Sweden)

    Zheng Liu

    Full Text Available STUDY DESIGN: Meta-analysis. BACKGROUND: Bilateral pedicle screw fixation (PS after lumbar interbody fusion is a widely accepted method of managing various spinal diseases. Recently, unilateral PS fixation has been reported as effective as bilateral PS fixation. This meta-analysis aimed to comparatively assess the efficacy and safety of unilateral PS fixation and bilateral PS fixation in the minimally invasive (MIS lumbar interbody fusion for one-level degenerative lumbar spine disease. METHODS: MEDLINE/PubMed, EMBASE, BIOSIS Previews, and Cochrane Library were searched through March 30, 2014. Randomized controlled trials (RCTs and controlled clinical trials (CCTs on unilateral versus bilateral PS fixation in MIS lumbar interbody fusion that met the inclusion criteria and the methodological quality standard were retrieved and reviewed. Data on participant characteristics, interventions, follow-up period, and outcomes were extracted from the included studies and analyzed by Review Manager 5.2. RESULTS: Six studies (5 RCTs and 1 CCT involving 298 patients were selected. There were no significant differences between unilateral and bilateral PS fixation procedures in fusion rate, complications, visual analogue score (VAS for leg pain, VAS for back pain, Oswestry disability index (ODI. Both fixation procedures had similar length of hospital stay (MD = 0.38, 95% CI = -0.83 to 1.58; P = 0.54. In contrast, bilateral PS fixation was associated with significantly more intra-operative blood loss (P = 0.002 and significantly longer operation time (P = 0.02 as compared with unilateral PS fixation. CONCLUSIONS: Unilateral PS fixation appears as effective and safe as bilateral PS fixation in MIS lumbar interbody fusion but requires less operative time and causes less blood loss, thus offering a simple alternative approach for one-level lumbar degenerative disease.

  8. Percutaneous pedicle screw fixation through the pedicle of fractured vertebra in the treatment of type A thoracolumbar fractures using Sextant system: an analysis of 38 cases

    OpenAIRE

    Wang, Hong-Wei; Li, Chang-Qing; Zhou, Yue; Zhang, Zheng-Feng; Wang, Jian; Chu, Tong-Wei

    2010-01-01

    To prospectively evaluate the feasibility, safety and efficacy of the percutaneous pedicle screw fixation through the pedicle of fractured vertebra in the treatment of type A thoracolumbar fractures using Sextant system in the retrospective non- randomized case-control study.

  9. Efficacy of radial styloid targeting screws in volar plate fixation of intra-articular distal radial fractures: a biomechanical study in a cadaver fracture model

    Directory of Open Access Journals (Sweden)

    Yamashita Toshihiko

    2010-12-01

    Full Text Available Abstract Background The locking screws target the radial styloid, theoretically provide greater stability against radial styloid fragment. However, it is unknown whether the radial styloid locking screws increased the stability of the volar plating system fixation along the entire distal radius or not. In this study, we evaluated the stability of the volar plating system fixation with or without the radial styloid screws using a biomechanical study in a cadaver fracture model. Methods Six matched pairs of fresh-frozen human cadaver wrists complete from the proximal forearm to the metacarpal bones were prepared to simulate standardized 3-part intra-articular and severe comminuted fractures. Specimens were fixed using the volar plating system with or without 2 radial styloid screws. Each specimen was loaded at a constant rate of 20 mm/min to failure. Load data was recorded and, ultimate strength and change in gap between distal and proximal fragments were measured. Data for ultimate strength and screw failure after failure loading were compared between the 2 groups. Results The average ultimate strength at failure of the volar plate fixation with radial styloid screws (913.5 ± 157.1 N was significantly higher than that without them (682.2 ± 118.6 N. After failure loading, the average change in gap between the ulnar and proximal fragment was greater than that between the radial and proximal fragment. The number of bent or broken screws in ulnar fragment was higher than that in radial fragment. The number of specimens with bent or broken screws in cases with radial styloid screws was fewer than that in the fixation without radial styloid screws group. Conclusion The ulnar fragment is more intensively stressed than the radial fragment under axial loading of distal radius at full wrist extension. The radial styloid screws were effective in stable volar plate fixation of distal radial fractures.

  10. Clinical study on the application of minimally invasive percutaneous pedicle screw fixation in single segment thoracolumbar fracture without neurological symptoms

    Directory of Open Access Journals (Sweden)

    Jin-ping LIU

    2016-04-01

    Full Text Available Objective To discuss the clinical effects of minimally invasive percutaneous pedicle screw fixation in the treatment of single segment thoracolumbar fracture without neurological symptoms.  Methods From June 2012 to October 2014, 38 neurologically intact patients with thoracolumbar fracture underwent surgeries, including open pedicle screw fixation in 16 cases and percutaneous pedicle screw fixation in 22 cases. The incision length, operation time, intraoperative blood loss, postoperative drainage and postoperative complication were recorded and compared between 2 groups. Thoracolumbar orthophoric, lateral and flexion-extension X-ray was used to measure sagittal Cobb angle and height of injured anterior vertebral body before and after operation. Modified Macnab evaluation was used to assess the curative effects 3 months after operation. Results The success rate of operations in 38 patients was 100%. There were a total of 114 vertebral bodies fused and 228 pedicle screws implanted. Patients in the percutaneous pedicle screw group had smaller incision length [(10.55 ± 1.23 cm vs (18.50 ± 2.50 cm, P = 0.000], less intraoperative blood loss [(32.55 ± 7.22 ml vs (320.50 ± 15.48 ml, P = 0.000], shorter hospital stay [(6.55 ± 1.50 d vs (13.50 ± 2.52 d, P = 0.000], and without postoperative drainage. The follow-up after operation ranged from 3 to 6 months, with the average time of (4.65 ± 1.24 months. Cobb angle was reduced (P = 0.000 and height of injured anterior vertebral body were improved signifcantly (P = 0.000 3 months after surgery in both groups. The total effective rate was 14/16 in open surgery group, and 86.36% (19/22 in percutaneous pedicle screw group, however, the difference between 2 groups was not significant (P = 1.000. Conclusions Minimally invasive percutaneous pedicle screw fixation is a surgical method with less iatrogenic injury, less intraoperative blood loss and quick recovery for patients with thoracolumbar fracture

  11. Percutaneous Facet Screw Fixation in the Treatment of Symptomatic Recurrent Lumbar Facet Joint Cyst: A New Technique

    International Nuclear Information System (INIS)

    We present a case of percutaneous treatment of symptomatic recurrent lumbar facet joint cyst resistant to all medical treatments including facet joint steroid injection. Percutaneous transfacet fixation was then performed at L4–L5 level with a cannulated screw using CT and fluoroscopy guidance. The procedure time was 30 min. Using the visual analog scale (VAS), pain decreased from 9.5, preoperatively, to 0 after the procedure. At 6-month follow-up, an asymptomatic cystic recurrence was observed, which further reduced at the 1-year follow-up. Pain remained stable (VAS at 0) during all follow-ups. CT- and fluoroscopy-guided percutaneous cyst rupture associated with facet screw fixation could be an alternative to surgery in patients suffering from a symptomatic recurrent lumbar facet joint cyst

  12. Percutaneous Facet Screw Fixation in the Treatment of Symptomatic Recurrent Lumbar Facet Joint Cyst: A New Technique

    Energy Technology Data Exchange (ETDEWEB)

    Amoretti, Nicolas, E-mail: amorettinicolas@yahoo.fr; Gallo, Giacomo, E-mail: giacomo.gallo83@gmail.com; Bertrand, Anne-Sophie, E-mail: asbertrand3@hotmail.com [Centre Hospitalier Universitaire de Nice (France); Bard, Robert L., E-mail: rbard@cancerscan.com [New York Medical College (United States); Kelekis, Alexis, E-mail: akelekis@med.uoa.gr [University General Hospital “ATTIKON” (Greece)

    2016-01-15

    We present a case of percutaneous treatment of symptomatic recurrent lumbar facet joint cyst resistant to all medical treatments including facet joint steroid injection. Percutaneous transfacet fixation was then performed at L4–L5 level with a cannulated screw using CT and fluoroscopy guidance. The procedure time was 30 min. Using the visual analog scale (VAS), pain decreased from 9.5, preoperatively, to 0 after the procedure. At 6-month follow-up, an asymptomatic cystic recurrence was observed, which further reduced at the 1-year follow-up. Pain remained stable (VAS at 0) during all follow-ups. CT- and fluoroscopy-guided percutaneous cyst rupture associated with facet screw fixation could be an alternative to surgery in patients suffering from a symptomatic recurrent lumbar facet joint cyst.

  13. Surgical outcome of posterior lumbar interbody fusion with pedicle screw fixation for lumbar spondylolisthesis

    International Nuclear Information System (INIS)

    Problems of lumbar spondylolisthesis treatment are many surgical tactics, elderly patient, osteoporosis, complications and recurrence of the symptoms. PLIF (posterior lumbar interbody fusion) and PS (pedicle screw) fixation technique for lumbar spondylolisthesis provide good patient satisfaction. Good outcome has been reported by only laminectomy alone, but patient satisfaction becomes worse year after year. The role of instrumentation for lumbar spondylolisthesis is decompression of the nerve root, correction of lumbar pathologies, bony fusion and early mobilization. We show our surgical technique and long term outcome of PLIF with PS for lumbar spondylolisthesis. Three hundred and fifty cases of lumbar spondylolisthesis were operated on in Department of Neurosurgery, Fujita Health University during the period of from December 1992 to August 2008. Patient background: age 16-84 years old (mean 62.5), Gender: male 153, female 197. Follow-up period 1-180 months (mean 61.2). Degenerative: 255, Isthmic: 63, Dysplastic: 10, Fracture: 5 and scoliosis 16 cases. Surgical procedure was PS with interbody fusion cage: 331, Hybrid cage (titanium cage with hydroxyapatite) 314, PS with Cerabone: 2 and PS with autograft: 17. CT was done to evaluate bony fusion postoperatively. Post operative improvements by JOA (Japan Orthopedic Association) score is 11.4 before surgery, 24.1 (post op. within 2 years), 25.4 (post op. 2-5 years), 25.0 (post op. 5-10 years) and 22.4 (post op. 10-15 years). Significant improvements were observed in %Slip and Slip angle but no remarkable change was observed in lumbar lordotic angle by postoperative X-ray evaluation. No root injury, and systemic complication except 4 cases of cerebrospinal fluid (CSF) leakage during surgery. Two cases were reoperated in whom cage with autograft migration due to pseudoarthrosis. Two cases had to undergo screw and cage system removal due to infection. Two cases of adjacent level stenosis had to undergo operation 10

  14. Titanium-alloy enhances bone-pedicle screw fixation: mechanical and histomorphometrical results of titanium-alloy versus stainless steel

    OpenAIRE

    Christensen, F.B.; Dalstra, M.; Sejling, F.; Overgaard, S.; Bünger, C.

    2000-01-01

    Several types of pedicle screw systems have been utilized to augment lumbar spine fusion. The majority of these systems are made of stainless steel (Ss), but titanium-alloy (Ti-alloy) devices have recently been available on the market. Ti-alloy implants have several potential advantages over Ss ones. High bioactivity and more flexibility may improve bone ingrowth and mechanical fixation, and the material also offers superior magnetic resonance imaging (MRI) and computed tomography (CT) resolu...

  15. Treatment of Displaced Sacroiliac Fracture Using the Lateral Window for Short Plate Buttress Reduction and Percutaneous Sacroiliac Screw Fixation

    Science.gov (United States)

    Murphy, Colin G.; Gill, James R.; Carrothers, Andrew D.; Hull, Peter D.

    2016-01-01

    Fractures through the sacroiliac joint are very challenging to treat, technically difficult to reduce through closed methods on account of the multiaxial displacement of fractures fragments, frequently occur in very unwell patients, and have poor outcomes if malreduction is present. We describe a technique utilising the lateral window and a short buttress plate to reduce and stabilize the fragments prior to percutaneous fixation with sacroiliac screws. PMID:27200398

  16. Biomechanical Comparison of Spinal Fusion Methods Using Interspinous Process Compressor and Pedicle Screw Fixation System Based on Finite Element Method

    Science.gov (United States)

    Choi, Jisoo; Kim, Sohee

    2016-01-01

    Objective To investigate the biomechanical effects of a newly proposed Interspinous Process Compressor (IPC) and compare with pedicle screw fixation at surgical and adjacent levels of lumbar spine. Methods A three dimensional finite element model of intact lumbar spine was constructed and two spinal fusion models using pedicle screw fixation system and a new type of interspinous devices, IPC, were developed. The biomechanical effects such as range of motion (ROM) and facet contact force were analyzed at surgical level (L3/4) and adjacent levels (L2/3, L4/5). In addition, the stress in adjacent intervertebral discs (D2, D4) was investigated. Results The entire results show biomechanical parameters such as ROM, facet contact force, and stress in adjacent intervertebral discs were similar between PLIF and IPC models in all motions based on the assumption that the implants were perfectly fused with the spine. Conclusion The newly proposed fusion device, IPC, had similar fusion effect at surgical level, and biomechanical effects at adjacent levels were also similar with those of pedicle screw fixation system. However, for clinical applications, real fusion effect between spinous process and hooks, duration of fusion, and influence on spinous process need to be investigated through clinical study. PMID:26962413

  17. A comparative study of pedicle screw fixation in dorsolumbar spine by freehand versus image-assisted technique: A cadaveric study

    Directory of Open Access Journals (Sweden)

    Archit Agarwal

    2016-01-01

    Full Text Available Background: New and expensive technology such as three-dimensional computer assisted surgery is being used for pedicle screw fixation in dorsolumbar spine. Their availability, expenses and amount of radiation exposure are issues in a developing country. On the contrary, freehand technique of pedicle screw placement utilizes anatomic landmarks and tactile palpation without fluoroscopy or navigation to place pedicle screws. The purpose of this study was to analyze and compare the accuracy of freehand and image-assisted technique to place pedicle screws in the dorsolumbar spine of cadavers by an experienced surgeon and a resident. Evaluation was done using dissection of pedicle and computed tomography (CT imaging. Materials and Methods: Ten cadaveric dorsolumbar spines were exposed by a posterior approach. Titanium pedicle screws were inserted from D5 to L5 vertebrae by freehand and image-assisted technique on either side by an experienced surgeon and a resident. CT was obtained. A blinded radiologist reviewed the imaging. The spines were then dissected to do a macroscopic examination. Screws, having evidence of cortical perforation of more than 2 mm on CT, were considered to be a significant breach. Results: A total of 260 pedicle screws were placed. The surgeon and the resident placed 130 screws each. Out of 130 screws, both of them placed 65 screws each by freehand and image- assisted technique each. The resident had a rate of 7.69% significant medial and 10.76% significant lateral breach with freehand technique while with image-assisted had a rate of 3.07% significant medial and 9.23% significant lateral breach. The expert surgeon had a rate of 6.15% significant medial and 1.53% significant lateral breach with freehand technique while with image-assisted had a rate of 3.07% significant medial and 6.15% significant lateral breach on CT evaluation. Conclusion: Freehand technique is as good as the image-assisted technique. Under appropriate

  18. Combined circular external fixation and open reduction internal fixation with pro-syndesmotic screws for repair of a diabetic ankle fracture

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    Zacharia Facaros

    2010-10-01

    Full Text Available The surgical management of ankle fractures among the diabetic population is associated with higher complication rates compared to the general population. Efforts toward development of better methods in prevention and treatment are continuously evolving for these injuries. The presence of peripheral neuropathy and the possible development of Charcot neuroarthropathy in this high risk patient population have stimulated much surgical interest to create more stable osseous constructs when open reduction of an ankle fracture/dislocation is required. The utilization of multiple syndesmotic screws (pro-syndesmotic screws to further stabilize the ankle mortise has been reported by many foot and ankle surgeons. In addition, transarticular Steinmann pins have been described as an adjunct to traditional open reduction with internal fixation (ORIF of the ankle to better stabilize the talus, thus minimizing risk of further displacement, malunion, and Charcot neuroarthropathy. The authors present a unique technique of ORIF with pro-syndesmotic screws and the application of a multi-plane circular external fixator for management of a neglected diabetic ankle fracture that prevented further deformity while allowing a weight-bearing status. This technique may be utilized for the management of complex diabetic ankle fractures that are prone to future complications and possible limb loss.

  19. Impact of Different Screw Designs on Durability of Fracture Fixation: In Vitro Study with Cyclic Loading of Scaphoid Bones

    Science.gov (United States)

    Gruszka, Dominik; Herr, Robert; Hely, Hans; Hofmann, Peer; Klitscher, Daniela; Hofmann, Alexander; Rommens, Pol Maria

    2016-01-01

    Purpose The use of new headless compression screws (HCSs) for scaphoid fixation is growing, but the nonunion rate has remained constant. The aim of this study was to compare the stability of fixation resulting from four modern HCSs using a simulated fracture model to determine the optimal screw design(s). Methods We tested 40 fresh-frozen cadaver scaphoids treated with the Acumed Acutrak 2 mini (AA), the KLS Martin HBS2 midi (MH), the Stryker TwinFix (ST) and the Synthes HCS 3.0 with a long thread (SH). The bones with simulated fractures and implanted screws were loaded uniaxially into flexion for 2000 cycles with a constant bending moment of 800 Nmm. The angulation of the fracture fragments was measured continuously. Data were assessed statistically using the univariate ANOVA test and linear regression analysis, and the significance level was set at p < 0.05. Results The median angulation of bone fragments φ allowed by each screw was 0.89° for AA, 1.12° for ST, 1.44° for SH and 2.36° for MH. With regards to linear regression, the most reliable curve was achieved by MH, with a coefficient of determination of R2 = 0.827. This was followed by AA (R2 = 0.354), SH (R2 = 0.247) and ST (R2 = 0.019). Data assessed using an adapted ANOVA model showed no statistically significant difference (p = 0.291) between the screws. Conclusions The continuous development of HCSs has resulted in very comparable implants, and thus, at this time, other factors, such as surgeons’ experience, ease of handling and price, should be taken into consideration. PMID:26741807

  20. Impact of Different Screw Designs on Durability of Fracture Fixation: In Vitro Study with Cyclic Loading of Scaphoid Bones.

    Directory of Open Access Journals (Sweden)

    Dominik Gruszka

    Full Text Available The use of new headless compression screws (HCSs for scaphoid fixation is growing, but the nonunion rate has remained constant. The aim of this study was to compare the stability of fixation resulting from four modern HCSs using a simulated fracture model to determine the optimal screw design(s.We tested 40 fresh-frozen cadaver scaphoids treated with the Acumed Acutrak 2 mini (AA, the KLS Martin HBS2 midi (MH, the Stryker TwinFix (ST and the Synthes HCS 3.0 with a long thread (SH. The bones with simulated fractures and implanted screws were loaded uniaxially into flexion for 2000 cycles with a constant bending moment of 800 Nmm. The angulation of the fracture fragments was measured continuously. Data were assessed statistically using the univariate ANOVA test and linear regression analysis, and the significance level was set at p < 0.05.The median angulation of bone fragments φ allowed by each screw was 0.89° for AA, 1.12° for ST, 1.44° for SH and 2.36° for MH. With regards to linear regression, the most reliable curve was achieved by MH, with a coefficient of determination of R2 = 0.827. This was followed by AA (R2 = 0.354, SH (R2 = 0.247 and ST (R2 = 0.019. Data assessed using an adapted ANOVA model showed no statistically significant difference (p = 0.291 between the screws.The continuous development of HCSs has resulted in very comparable implants, and thus, at this time, other factors, such as surgeons' experience, ease of handling and price, should be taken into consideration.

  1. Clinical results of the re-fixation of a Chevron olecranon osteotomy using an intramedullary cancellous screw and suture tension band

    OpenAIRE

    Wagener, Marc L.; Dezillie, Marleen; Hoendervangers, Yvette; Eygendaal, Denise

    2015-01-01

    Exposure of the distal humerus in case of an articular fracture is often performed through a Chevron osteotomy of the olecranon. Several options have been described for re-fixation of the Chevron osteotomy. Pull-out of the hard-wear is often seen as complication. In this study, an evaluation of the re-fixation of the Chevron osteotomy through a cancellous screw and suture tension band was performed. The data of 19 patients in whom a Chevron osteotomy was re-fixated with a cancellous screw in ...

  2. Interference screw versus Endoscrew fixation for anterior cruciate ligament reconstruction: A biomechanical comparative study in sawbones and porcine knees

    Directory of Open Access Journals (Sweden)

    Chu-Chih Hung

    2014-04-01

    Full Text Available Interference screw fixation is one of the most common methods for ligament reconstruction. Although the advantages and clinical outcomes of this procedure have been widely reported, post-surgical complications often arise. The purpose of this study was to evaluate a new femoral fixation device, the Endoscrew, for anterior cruciate ligament (ACL reconstruction. We performed a mechanical test in accordance with American Society for Testing and Materials (ASTM standards and an in vitro biomechanical study. An axial pullout test was conducted to evaluate the mechanical properties of the new device and the interference screw when implanted in solid rigid polyurethane foam test blocks. The biomechanical test used porcine femora to evaluate the initial fixation strength between these two implants. The maximum pullout force of the interference screw group [722.05 ± 130.49 N (N] was significantly greater (p < 0.01 than the Endoscrew group (440.79 ± 26.54 N when implanted in polyurethane foam 320 kg/m3 density. With polyurethane foam 160 kg/m3 density, the maximum pullout forces were (242.61 ± 37.36 N (p < 0.001 and (99.33 ± 30.01 N for the interference screw group and Endoscrew group, respectively. In the in vitro mechanical study, the Endoscrew (646.39 ± 72.38 N required a significantly greater ultimate load prior to failure (p < 0.05 when compared with the interference screw (489.72 ± 138.64 N. With regard to pullout stiffness, there was no statistically significant difference (p < 0.13 between the Endoscrew group (99.15 ± 12.16 N/mm and the interference screw group (87.96 ± 11.12 N/mm. The cyclic stiffness was also not significantly different (p < 0.44 between the Endoscrew group (93.09 ± 16.07 N/mm and the interference screw group (85.78 ± 14.76 N/mm. The axial pullout test showed that the strength of the Endoscrew was close to the fixation strength required for daily activities, but it is

  3. The Use of Percutaneous Lumbar Fixation Screws for Bilateral Pedicle Fractures with an Associated Dislocation of a Lumbar Disc Prosthesis

    Directory of Open Access Journals (Sweden)

    William D. Harrison

    2013-01-01

    Full Text Available Study Design. Case report. Objective. To identify a safe technique for salvage surgery following complications of total disc replacement. Summary of Background Data. Lumbar total disc replacement (TDR is considered by some as the gold standard for discogenic back pain. Revision techniques for TDR and their complications are in their infancy. This case describes a successful method of fixation for this complex presentation. Methods and Results. A 48-year-old male with lumbar degenerative disc disease and no comorbidities. Approximately two weeks postoperatively for a TDR, the patient represented with acute severe back pain and the TDR polyethylene inlay was identified as dislocated anteriorly. Subsequent revision surgery failed immediately as the polyethylene inlay redislocated intraoperatively. Further radiology identified bilateral pedicle fractures, previously unseen on the plain films. The salvage fusion of L5/S1 reutilized the anterior approach with an interbody fusion cage and bone graft. The patient was then turned intraoperatively and redraped. The percutaneous pedicle screws were used to fix L5 to the sacral body via the paracoccygeal corridor. Conclusion. The robust locking screw in the percutaneous screw allowed a complete fixation of the pedicle fractures. At 3-year followup, the patient has an excellent result and has returned to playing golf.

  4. CT-guided screw fixation of vertical sacral fractures in local anaesthesia using a standard CT

    International Nuclear Information System (INIS)

    To evaluate time efficiency, radiation dose, precision and complications of percutaneous iliosacral screw placement under CT-guidance in local anaesthesia. Retrospective analysis of 143 interventions in 135 patients during a period of 42 months. Implant failures could be evaluated in 85/182 screws and bony healing or refracturing in 46/182 screws. A total of 182 iliosacral screw placements in 179 vertical sacral fractures (105 unilateral, 37 bilateral) took place in 135 patients. 166/179 of the sacral fractures were detected in Denis zone 1, 10 in Denis zone 2 and 3 in Denis zone 3. No screw misplacements including the simultaneous bilateral procedures were noted. The average time for a unilateral screw placement was 23 minutes (range: 14-52 minutes) and 35 minutes (range: 21-60 minutes) for simultaneous bilateral screwing. The dose length product was 365 mGy x cm (range: 162-1014 mGy x cm) for the unilateral and 470 mGy x cm (range: 270-1271 mGy x cm) for the bilateral procedure. 1 gluteal bleeding occurred as the only acute minor complication (0.7%). Fracture healing was verified with follow-up CTs in 42/46 sacral fractures after screw placement. Backing out occurred in 12/85 screws between 6 and 69 days after intervention. In 8 patients contralateral stress fractures were detected after unilateral screw placement between day 10 and 127 (average: 48 days). CT-guided iliosacral screw placement in sacral fractures is a safe tool providing a very high precision. The radiation dose is in the order of a diagnostic CT of the pelvis for both unilateral and bilateral screws. Contralateral stress fractures in unilateral screw placements have to be considered during the first weeks after intervention.

  5. Bold镙钉治疗Jones骨折%Treatment of 16 cases Jones fractures by open reduction and bold screw fixation

    Institute of Scientific and Technical Information of China (English)

    单宇; 蒋富贵; 张晓剑; 徐能

    2013-01-01

    Objective To evaluate the clinical effect of Bold screw fixation in the treatment of jones fracture.Method From March 2006 to May 2012,16 case of Jones fracture were treated by open reduction and Bold screw fixation.Result All the patients were obtained healing of bone reunion and followed up for 6~12 months,no residual pain and nonunion.According to Maryland foot scording system,9 cases were excellent,5 good,2 fair and the rate of excellent and good was 87.5 %.Conclusion Bold screw fixation is an effective therapy for Jones fracture of open reduction and it has the benefit of early exercise,no need to remove,fixed solid.%目的 探讨Bold螺钉内固定治疗Jones骨折的临床疗效.方法 2006年3月~2012年5月,采用切开复位Bold螺钉内固定治疗Jones骨折16例.结果 16例均获随访,随访时间6~12m,均获得骨性愈合,未残留疼痛或骨不愈合.按Maryland足部评分系统评分,优9例,良5例,可2例,优良率87.5%.结论 Bold螺钉治疗Jones骨折具有早期功能锻炼、无需取出、固定稳固等优点,是治疗Jones骨折的有效方法.

  6. Scar due to skin incision for screw fixation through the transbuccal approach after sagittal split ramus osteotomy.

    Science.gov (United States)

    Muto, Toshitaka

    2012-05-01

    Most rigid fixation techniques after sagittal split ramus osteotomies of the mandible involve the transbuccal approach. A skin incision in the cheek carries with it possible undesirable sequelae, such as noticeable scarring. The aim of this study was to investigate whether there is scarring in the face after this technique. For screw insertion, a 5-mm stab incision was performed on 40 Japanese patients (20 men and 20 women) with class III occlusion. After surgery, gross examination (via the naked eyes) of the skin incision was performed monthly for 1 year by the same oral surgeon. In all cases, the skin incision had disappeared by 1 year after the surgery. PMID:22627425

  7. Posterior Titanium Screw Fixation without Debridement of Infected Tissue for the Treatment of Thoracolumbar Spontaneous Pyogenic Spondylodiscitis

    Science.gov (United States)

    Iacoangeli, Maurizio; Nasi, Davide; Nocchi, Niccolo; Di Rienzo, Alessandro; di Somma, Lucia; Colasanti, Roberto; Vaira, Carmela; Benigni, Roberta; Liverotti, Valentina; Scerrati, Massimo

    2016-01-01

    Study Design Retrospective study. Purpose The aim of our study was to analyze the safety and effectiveness of posterior pedicle screw fixation for treatment of pyogenic spondylodiscitis (PSD) without formal debridement of the infected tissue. Overview of Literature Posterior titanium screw fixation without formal debridement of the infected tissue and anterior column reconstruction for the treatment of PSD is still controversial. Methods From March 2008 to June 2013, 18 patients with PSD underwent posterior titanium fixation with or without decompression, according to their neurological deficit. Postero-lateral fusion with allograft transplantation alone or bone graft with both the allogenic bone and the autologous bone was also performed. The outcome was assessed using the visual analogue scale (VAS) for pain and the Frankel grading system for neurological status. Normalization both of C-reactive protein (CRP) and erythrocyte sedimentation rate was adopted as criterion for discontinuation of antibiotic therapy and infection healing. Segmental instability and fusion were also analyzed. Results At the mean follow-up time of 30.16 months (range, 24–53 months), resolution of spinal infection was achieved in all patients. The mean CRP before surgery was 14.32±7.9 mg/dL, and at the final follow-up, the mean CRP decreased to 0.5±0.33 mg/dL (p <0.005). Follow-up computed tomography scan at 12 months after surgery revealed solid fusion in all patients. The VAS before surgery was 9.16±1.29 and at the final follow-up, it improved to 1.38±2.03, which was statistically significant (p <0.05). Eleven patients out of eighteen (61.11%) with initial neurological impairment had an average improvement of 1.27 grades at the final follow-up documented with the Frankel grading system. Conclusions Posterior screw fixation with titanium instrumentation was safe and effective in terms of stability and restoration of neurological impairment. Fixation also rapidly reduced back pain.

  8. Is a Sliding Hip Screw or IM Nail the Preferred Implant for Intertrochanteric Fracture Fixation?

    Science.gov (United States)

    Aros, Brian; Tosteson, Anna N. A.; Gottlieb, Daniel J.

    2008-01-01

    This study was performed to determine whether patients who sustain an intertrochanteric fracture have better outcomes when stabilized using a sliding hip screw or an intramedullary nail. A 20% sample of Part A and B entitled Medicare beneficiaries 65 years or older was used to generate a cohort of patients who sustained intertrochanteric femur fractures between 1999 and 2001. Two fracture implant groups, intramedullary nail and sliding hip screw, were identified using Current Procedural Terminology and International Classification of Diseases, 9th Revision codes. The cohort consisted of 43,659 patients. Patients treated with an intramedullary nail had higher rates of revision surgery during the first year than those treated with a sliding hip screw (7.2% intramedullary nail versus 5.5% sliding hip screw). Mortality rates at 30 days (14.2% intramedullary nail versus 15.8% sliding hip screw) and 1 year (30.7% intramedullary nail versus 32.5% sliding hip screw) were similar. Adjusted secondary outcome measures showed significant increases in the intramedullary nail group relative to the sliding hip screw group for index hospital length of stay, days of rehabilitation services in the first 6 months after discharge, and total expenditures for doctor and hospital services. Level of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18465180

  9. Effects of bioabsorbable miniplateversus miniature titanium fixation system on the stability of mandibular fractures%生物可吸收性微型接骨板与微型钛内固定系统对下颌骨骨折稳定性的影响

    Institute of Scientific and Technical Information of China (English)

    邱勋定

    2015-01-01

    BACKGROUND:Bioabsorbable miniplates have good achievements after implantation, which have similar effect to the miniature titanium fixation system. Due to its absorbability, the bioabsorbable miniplate cannot exist in the body for a long time, which cannot influence bone stresses, cannot result in bone tissue atrophy, and have fewer complications than traditional metal internal fixations. OBJECTIVE:To explore and analyze the effects of miniature titanium internal fixation systemversus bioabsorbable miniplates on fracture stability in patients with mandibular fractures. METHODS:Ninety patients with mandibular fractures admitted at the Department of Stomatology, Hainan General Hospital from January 2013 to May 2015 were enroled. Al the subjects were divided into two groups according to different internal fixations: miniature titanium group and bioabsorbable miniplate group. RESULTS AND CONCLUSION:At 3 months after internal fixation, the stability rate was significantly higher in the bioabsorbable miniplate group than the miniature titanium group. At 1 year after internal fixation, the range of motion of the processus condyloideus was significantly higher in the miniature titanium group than the bioabsorbable miniplate group. These findings suggest that the bioabsorbable miniplate and miniature titanium internal fixation system both have good clinical outcomes in the treatment of mandibular fractures. The miniature titanium internal fixation system is easy to use and has good stability; the bioabsorbable miniplate can reduce foreign body reaction and prevent osteoporosis, and it has an ideal stability in combination with intermaxilary traction. Therefore, what kind of internal fixations is selected should be determined based on the wilingness and conditions of patients.%背景:生物可吸收性微型接骨板植入后患者恢复较好,且效果与微型钛内固定相似,并且由于其可吸收性,不会作为异物长期存在体内,无需二次手术

  10. Biomechanical comparison of pedicle screws versus spinous process screws in C2 vertebra A cadaveric study

    Directory of Open Access Journals (Sweden)

    Guan-yi Liu

    2014-01-01

    Conclusion: Spinous process screws provide comparable pullout strength to pedicle screws of the C2. Spinous process screws may provide an alternative to pedicle screws fixation, especially with unusual anatomy or stripped screws.

  11. Efficacy of open reduction and internal fixation with a miniplate and hollow screw in the treatment of Lisfranc injury

    Institute of Scientific and Technical Information of China (English)

    Baoliang Li; Wenbo Zhao; Lei Liu; Fuguo Huang; Guanglin Wang; Yue Fang

    2015-01-01

    Purpose:To investigate efficacy of open reduction and internal fixation with the miniplate and hollow screw in the treatment of Lisfranc injury.Methods:Ten cases of Lisfranc injury treated by open reduction,miniplate and hollow screw in our hospital were retrospectively analyzed.There were 6 males and 4 females with age ranging from 25 to 45 years (mean 32 years).Among them,one case was classified as Type A,six Type B and three Type C.Injury mechanism included road traffic accidents (3 cases),fall from height (5 cases) and hit by heavy object (2 cases).All injuries were closed without cerebral trauma or other complicated injuries.The time interval between injury and operation was 6-10 days (average 6.6 days).Postoperatively,the foot function was assessed using Visual Analogue Scales (VAS) and American Orthopaedic Foot and Ankle Society (AOFAS) Scales.Healing time and complications were observed.Results:All patients were followed up for 18-24 months (average 20 months).Anatomic reduction was achieved in all patients on images.There was statistical significance between preoperative score (7.89 ± 0.34) and score at postoperative 8 weeks (0.67 ± 0.13).According to the AOFAS score,5 cases were defined as excellent,3 cases as good and 2 cases as fair.During follow-up,there was no wound infection or complications except for osteoarthritis in 2 cases.Healing time ranged from 3 to 6 months with an average of 3.6 months.Conclusion:Anatomical reduction of Lisfranc injury can be achieved by open reduction and internal fixation with the miniplate and hollow screw.Normal structure of Lisfranc joint is regained to a great extent;injured ligaments were also repaired.Therefore,this method offers excellent curative effect and can avoid postoperative complications and improve the patients' quality of life.

  12. Efficacy of open reduction and internal fixation with a miniplate and hollow screw in the treatment of Lisfranc injury

    Directory of Open Access Journals (Sweden)

    Li Baoliang

    2015-07-01

    Full Text Available Purpose: To investigate efficacy of open reduction and internal fixation with the miniplate and hollow screw in the treatment of Lisfranc injury. Methods: Ten cases of Lisfranc injury treated by open reduction, miniplate and hollow screw in our hospital were retrospectively analyzed. There were 6 males and 4 females with age ranging from 25 to 45 years (mean 32 years. Among them, one case was classified as Type A, six Type B and three Type C. Injury mechanism included road traffic accidents (3 cases, fall from height (5 cases and hit by heavy object (2 cases. All injuries were closed without cerebral trauma or other complicated injuries. The time interval between injury and operation was 6e10 days (average 6.6 days. Postoperatively, the foot function was assessed using Visual Analogue Scales (VAS and American Orthopaedic Foot and Ankle Society (AOFAS Scales. Healing time and complications were observed. Results: All patients were followed up for 18e24 months (average 20 months. Anatomic reduction was achieved in all patients on images. There was statistical significance between preoperative score (7.89 ± 0.34 and score at postoperative 8 weeks (0.67 ± 0.13. According to the AOFAS score, 5 cases were defined as excellent, 3 cases as good and 2 cases as fair. During follow-up, there was no wound infection or complications except for osteoarthritis in 2 cases. Healing time ranged from 3 to 6 months with an average of 3.6 months. Conclusion: Anatomical reduction of Lisfranc injury can be achieved by open reduction and internal fixation with the miniplate and hollow screw. Normal structure of Lisfranc joint is regained to a great extent; injured ligaments were also repaired. Therefore, this method offers excellent curative effect and can avoid postoperative complications and improve the patients' quality of life.

  13. Percutaneous cannulated screw fixation of sacral fractures and sacroiliac joint disruptions with CT-controlled guidewires performed by interventionalists: Single center experience in treating posterior pelvic instability

    International Nuclear Information System (INIS)

    Highlights: • Minimally invasive sacroiliac screw fixation can be performed under CT-imaging. • Guidewires help in precise placement of cannulated sacroiliac screw. • Only a diminishing rate of misplacements can be seen. • The method appears to be a safe and very accurate procedure. - Abstract: Objective: The purpose of our study was to evaluate minimally invasive sacroiliac screw fixation for treatment of posterior pelvic instability with the help of CT controlled guidewires, assess its accuracy, safety and effectiveness, and discuss potential pitfalls. Methods: 100 guidewires and hollow titan screws were inserted in 38 patients (49.6 ± 19.5 years) suffering from 35 sacral fractures and/or 16 sacroiliac joint disruptions due to 33 (poly-)traumatic, 2 osteoporotic and 1 post-infectious conditions. The guidewire and screw positions were analyzed in multiplanar reconstructions. Results: The mean minimal distance between guidewire and adjacent neural foramina was 4.5 ± 2.01 mm, with a distinctly higher precision in S1 than S2. Eight guidewires showed cortical contacts, resulting in a total of 2% mismatched screws with subsequent wall violation. The fracture gaps were reduced from 3.6 ± 0.53 mm to 1.2 ± 0.54 mm. During follow-up 3 cases of minor iatrogenic sacral impaction (<5 mm) due to the bolting and 2 cases of screw loosening were observed. Interventional time was 84.0 min with a mean of 2.63 screws per patient whilst acquiring a mean of 93.7 interventional CT-images (DLP 336.7 mGy cm). Conclusions: The treatment of posterior pelvic instability with a guidewire-based screw insertion technique under CT-imaging results in a very high accuracy and efficacy with a low complication rate. Careful attention should be drawn to radiation levels

  14. Percutaneous cannulated screw fixation of sacral fractures and sacroiliac joint disruptions with CT-controlled guidewires performed by interventionalists: Single center experience in treating posterior pelvic instability

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Sebastian, E-mail: sebastian.fischer@kgu.de [Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Vogl, Thomas J. [Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Marzi, Ingo [Department of Trauma, Hand and Reconstructive Surgery, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Zangos, Stephan; Wichmann, Julian L.; Scholtz, Jan-Erik; Mack, Martin G. [Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Schmidt, Sven [Orthopaedic University Hospital Friedrichsheim, Marienburgstraße, 260528 Frankfurt (Germany); Eichler, Katrin [Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany)

    2015-02-15

    Highlights: • Minimally invasive sacroiliac screw fixation can be performed under CT-imaging. • Guidewires help in precise placement of cannulated sacroiliac screw. • Only a diminishing rate of misplacements can be seen. • The method appears to be a safe and very accurate procedure. - Abstract: Objective: The purpose of our study was to evaluate minimally invasive sacroiliac screw fixation for treatment of posterior pelvic instability with the help of CT controlled guidewires, assess its accuracy, safety and effectiveness, and discuss potential pitfalls. Methods: 100 guidewires and hollow titan screws were inserted in 38 patients (49.6 ± 19.5 years) suffering from 35 sacral fractures and/or 16 sacroiliac joint disruptions due to 33 (poly-)traumatic, 2 osteoporotic and 1 post-infectious conditions. The guidewire and screw positions were analyzed in multiplanar reconstructions. Results: The mean minimal distance between guidewire and adjacent neural foramina was 4.5 ± 2.01 mm, with a distinctly higher precision in S1 than S2. Eight guidewires showed cortical contacts, resulting in a total of 2% mismatched screws with subsequent wall violation. The fracture gaps were reduced from 3.6 ± 0.53 mm to 1.2 ± 0.54 mm. During follow-up 3 cases of minor iatrogenic sacral impaction (<5 mm) due to the bolting and 2 cases of screw loosening were observed. Interventional time was 84.0 min with a mean of 2.63 screws per patient whilst acquiring a mean of 93.7 interventional CT-images (DLP 336.7 mGy cm). Conclusions: The treatment of posterior pelvic instability with a guidewire-based screw insertion technique under CT-imaging results in a very high accuracy and efficacy with a low complication rate. Careful attention should be drawn to radiation levels.

  15. Effect of twist-orientation on mechanical properties of self-reinforced poly(lactic acid) screws in simulated body environment

    Science.gov (United States)

    Sakaguchi, Masato; Kobayashi, Satoshi; composite engineering lab Team

    Poly(lactic acid) (PLA) attracts much attention as a typical biodegradable polymer, and has been applied as a bone fixation device. As one of the methods to improve mechanical properties of PLA bone fixation device, orientations of molecular chains have been investigated. However, conventional uniaxial drawing could not improve mechanical properties along the other loading direction than the drawing direction, such as torsion. In this study, screw is treated as a bone fixation device. In order to improve torsional strength of a bioabsorbable PLA screw, twist-orientation method has been developed. PLA screw is prepared through a series of routes including extrusion molding, extrusion drawing, twist-orientation and forging. This screw was immersed in the phosphate buffer solution for 0, 8, 16 and 24 weeks, then shear strength, orientation function, crystallinity and molecular weight were measured. As a result, twist-orientation improves the initial torsional strength of PLA screw without the decrease in initial shear strength. In addition, the shear strength on twist-oriented screw is equivalent that of non-twist oriented screw during immersion until 24 weeks. This result shown that the twist-orientation does not decrease shear strength after immersion.

  16. Atlantoaxial arthrodesis using C1-C2 transarticular screw fixation in a case of Morquio syndrome

    Directory of Open Access Journals (Sweden)

    Arvind G Kulkarni

    2011-01-01

    Full Text Available Prophylactic or therapeutic arthrodesis is recommended for atlantoaxial instability in Morquio syndrome. Occipitocervical fusion, the common approach for upper cervical fusion in Morquio syndrome sacrifices the movements at the occipitoatlantal joints. The use of C1-C2 transarticular screws for achieving C1-C2 arthrodesis, without compromising mobility at the occipitoatlantal joint in Morquio syndrome has not been reported. We report a case of Morquio syndrome with atlantoaxial instability and odontoid hypoplasia, where we successfully achieved C1-C2 arthrodesis using transarticular screws and bone graft. The advantages of this method over other methods of atlantoaxial arthrodesis in Morquio syndrome have also been discussed.

  17. Hydroxyapatite coating enhances fixation of loaded pedicle screws: a mechanical in vivo study in sheep

    OpenAIRE

    Sandén, Bengt; Olerud, Claes; Larsson, Sune

    2001-01-01

    Loosening of the pedicle screws with subsequent non-union or loss of correction is a frequent problem in spinal instrumentation. In a clinical pilot study, coating of pedicle screws with plasma-sprayed hydroxyapatite (HA) resulted in a significant increase of removal torque. An experimental study was performed to investigate the effects of HA coating on the pull-out resistance. Thirteen sheep were operated on with destabilising laminectomies at two levels, L2-L3 and L4-L5. Two instrumentation...

  18. Minimally invasive transforaminal lumbar interbody fusion with percutaneous navigated guidewireless lumbosacral pedicle screw fixation.

    Science.gov (United States)

    Chen, Kevin S; Park, Paul

    2016-07-01

    This video details the minimally invasive approach for treatment of a symptomatic Grade II lytic spondylolisthesis with high-grade foraminal stenosis. In this procedure, the use of a navigated, guidewireless technique for percutaneous pedicle screw placement at the lumbosacral junction is highlighted following initial decompression and transforaminal interbody fusion. Key steps of the procedure are delineated that include positioning, exposure, technique for interbody fusion, intraoperative image acquisition, and use of a concise 2-step process for navigated screw placement without using guidewires. The video can be found here: https://youtu.be/2u6H4Pc_8To . PMID:27364422

  19. Percutaneous pedicle screw fixation through the pedicle of fractured vertebra in the treatment of type A thoracolumbar fractures using Sextant system: an analysis of 38 cases

    Directory of Open Access Journals (Sweden)

    WANG Hong-wei

    2010-06-01

    Full Text Available To prospectively evaluate the feasibility, safety and efficacy of the percutaneous pedicle screw fixation through the pedicle of fractured vertebra in the treatment of type A thoracolumbar fractures using Sextant system in the retrospective non- randomized case-control study.

  20. Clinical study on minimally invasive transforaminal lumbar interbody fusion combined with percutaneous pedicle screw fixation for degenerative lumbar scoliosis

    Directory of Open Access Journals (Sweden)

    Hao WU

    2016-04-01

    Full Text Available Objective To discuss the operative essentials and therapeutic effects of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF combined with percutaneous pedicle screw fixation for degenerative lumbar scoliosis (DLS.  Methods A total of 17 DLS patients without prior spinal diseases were treated by MIS-TLIF and percutaneous pedicle screw fixation from January 2013 to September 2015 in Xuanwu Hospital, Capital Medical University. The operation time, intraoperative blood loss, hospital stay, and postoperative complication were recorded in each patient. Visual Analogue Scale (VAS and Oswestry Disability Index (ODI were used to evaluate postoperative improvement of low back and leg pain, and clinical effects were assessed according to Medical Outcome Study 36-Item Short-Form Health Survey (SF-36. Coronal Cobb angle, sagittal lordosis angle and spinal deviation distances on coronal and sagittal plane were measured before operation, one week, 3 months after operation and in the last follow-up in spinal full-length X-ray examination. Fusion rate was calculated according to X-ray or CT scan, and the degree of decompression was evaluated by MRI.  Results Decompression and fusion levels ranged from T12-S1 vertebrae, and interbody fusion was performed in 17 patients and 56 levels were fused. Average operation time was 200 min (180-300 min, intraoperative blood loss was 320 ml (200-1000 ml and hospital stay was 8.21 d (5-12 d. All patients were followed-up for 12.13 months (5-24 months. Compared with preoperation, VAS (P = 0.000, for all and ODI scores (P = 0.000, for all decreased significantly, SF-36 score increased (P = 0.000, for all, coronal Cobb angle (P = 0.000, for all, sagittal lordosis angle (P = 0.000, for all, coronal and sagittal deviation (P = 0.000, for all decreased significantly one week and 3 months after operation and in the last follow-up. The improvement rate of ODI was (86.51 ± 6.02%, fusion rate of vertebral bodies

  1. Superior fixation of pegged trabecular metal over screw-fixed pegged porous titanium fiber mesh

    OpenAIRE

    Stilling, Maiken; Madsen, Frank; Odgaard, Anders; Rømer, Lone; Andersen, Niels Trolle; Rahbek, Ole; Søballe, Kjeld

    2011-01-01

    Background and purpose Lasting stability of cementless implants depends on osseointegration into the implant surface, and long-term implant fixation can be predicted using radiostereometric analysis (RSA) with short-term follow-up. We hypothesized that there would be improved fixation of high-porosity trabecular metal (TM) tibial components compared to low-porosity titanium pegged porous fiber-metal (Ti) polyethylene metal backings. Methods In a prospective, parallel-group, randomized unblind...

  2. [C1-C2 transarticular screw fixation of atlanto-axial instability with tetraparesis in rheumatoid patient--case report].

    Science.gov (United States)

    Chrzanowska, Anetta; Chrzanowski, Robert; Skura, Antoni

    2010-01-01

    A case of a 50-year-old patient with C1-C2 subluxation and concomitant neurological deficits in the course of rheumatoid arthritis has been described. In the article the diagnostic and therapeutic procedures, consisting mainly of surgical treatment, have been presented. Indications for the surgery were: a rapid disease progression observed during the last six months, and tetraparesis. The authors propose the choice of applied surgical technique by taking into account difficulties consequential to the anatomy of this region, as well as additional complications regarding the chronic inflammation process. The use of transarticular screw fixation method, together with concurrent spinal cord decompression allowed the stabilization of C1-C2 subluxation and improvement of the neurological state of the patient. PMID:21591367

  3. No effect of additional screw fixation of a cementless, all-polyethylene press-fit socket on migration, wear, and clinical outcome.

    Science.gov (United States)

    Minten, Michiel J M; Heesterbeek, Petra J C; Spruit, Maarten

    2016-08-01

    Background and purpose - Additional screw fixation of the all-polyethylene press-fit RM cup (Mathys) has no additional value for migration, in the first 2 years after surgery. However, the medium-term and long-term effects of screw fixation remain unclear. We therefore evaluated the influence of screw fixation on migration, wear, and clinical outcome at 6.5 years using radiostereometric analysis (RSA). Patients and methods - This study involved prolonged follow-up from a previous randomized controlled trial (RCT). We analyzed RSA radiographs taken at baseline and at 1-, 2-, and 6.5-year follow-up. Cup migration and wear were assessed using model-based RSA software. Wear was calculated as translation of the femoral head model in relation to the cup model. Total translation, rotation, and wear were calculated mathematically from results of the orthogonal components. Results - 27 patients (15 with screw fixation and 12 without) were available for follow-up at 6.5 (5.6-7.2) years. Total translation (0.50 mm vs. 0.56 mm) and rotation (1.01 degrees vs. 1.33 degrees) of the cup was low, and was not significantly different between the 2 groups. Wear increased over time, and was similar between the 2 groups (0.58 mm vs. 0.53 mm). Wear rate (0.08 mm/year vs. 0.09 mm/year) and clinical outcomes were also similar. Interpretation - Our results indicate that additional screw fixation of all-polyethylene press-fit RM cups has no additional value regarding medium-term migration and clinical outcome. The wear rate was low in both groups. PMID:27299418

  4. Comparison of the effect of posterior lumbar interbody fusion with pedicle screw fixation and interspinous fixation on the stiffness of adjacent segments

    Institute of Scientific and Technical Information of China (English)

    LI Chun-de; SUN Hao-lin; LU Hong-zhang

    2013-01-01

    stiffness of the cephalic adjacent segment L3/4 after fixation in the Wallis group was significantly higher than that of the PLIF group (P <0.05).Cadaver experiments showed that the stiffness of the cephalic adjacent segment in the Wallis group was significantly higher than that of the PLIF group after L4/5 segment fixation (P <0.05); the stiffness of the L5/S1 segment showed no significant difference between PLIF surgery and Wallis implantation (P >0.05).Conclusions After interspinous (Wallis) fixation,the stiffness of the cephalic adjacent segment increased.After PLIF with pedicle screw fixation,the stiffness of the cephalic adjacent segment decreased.An interspinous fixation system (Wallis) has a protective effect for cephalic adjacent segments for the immediate post-operative state.

  5. Analysis of elements in the soft tissue covering titanium plates and screws for internal bone fixation by the PIXE method

    International Nuclear Information System (INIS)

    We made a comparative study of the elements in the periosteum on titanium plates and screws for internal bone fixation, normal periosteum, and oral mucosa by the PIXE method. We studied 11 patients, 4 men and 7 women, with mandibular fracture or facial deformity. The implanted time length of the materials in the body was 5 to 16 months. The analyzed samples were 11 periostea on the materials, 11 normal periostea and 4 oral mucosae. The results were as follows. Twenty- four essential and 11 contaminated elements were detected in the periostea on the materials as well as in the normal periostea and the oral mucosae. In the mean values of titanium and aluminum, there were significantly higher values in the periostea on the materials than in the normal periostea. The mean concentration values of the other elements did not differ significantly between that in the periostea on the materials and that in the normal periostea. The concentration of titanium in the periostea on the materials was not correlated with sex, age of the patients, or the implanted time length. However, there was a significantly higher titanium concentration value in tile periostea on the plates than on the screws. Our results could indicate that the existence of a titanium element in the periostea on the materials was caused by its dissolution from the materials. (author)

  6. A Biomechanical Study Comparing Helical Blade with Screw Design for Sliding Hip Fixations of Unstable Intertrochanteric Fractures

    Directory of Open Access Journals (Sweden)

    Qiang Luo

    2013-01-01

    Full Text Available Dynamic hip screw (DHS is a well-established conventional implant for treating intertrochanteric fracture. However, revision surgery sometimes still occurs due to the cutting out of implants. A helical blade instead of threaded screw (DHS blade was designed to improve the fixation power of the osteoporotic intertrochanteric fracture. In this study, the biomechanical properties of DHS blade compared to the conventional DHS were evaluated using an unstable AO/OTA 31-A2 intertrochanteric fracture model. Fifty synthetic proximal femoral bone models with such configuration were fixed with DHS and DHS blade in five different positions: centre-centre (CC, superior-centre (SC, inferior-center (IC, centre-anterior (CA, and centre-posterior (CP. All models had undergone mechanical compression test, and the vertical and rotational displacements were recorded. The results showed that DHS blade had less vertical or rotational displacement than the conventional DHS in CC, CA, and IC positions. The greatest vertical and rotational displacements were found at CP position in both groups. Overall speaking, DHS blade was superior in resisting vertical or rotational displacement in comparison to conventional DHS, and the centre-posterior position had the poorest performance in both groups.

  7. Unstable Intertrochanteric Fracture Fixation – Is Proximal Femoral Locked Compression Plate Better Than Dynamic Hip Screw

    Science.gov (United States)

    Asif, Naiyer; Qureshi, Owais Ahmad; Jilani, Latif Zafar; Hamesh, Tajdar; Jameel, Tariq

    2016-01-01

    Background Intertrochanteric fractures are one of the most common fractures encountered in our practice. Most of them need operative intervention and union is achieved. As per the literature dynamic hip screw (DHS) is the gold standard for the treatment of these fractures, however problem arises with maintenance of neck shaft angle and proper reduction in unstable intertrochanteric fractures. The situation gets more complex when “cut out” of femoral head screw occurs either alone or in combination with varus collapse when they are treated with DHS. Here we are giving results of unstable intertrochanteric fractures treated with Proximal Femoral Locked Compression Plate (PFLCP) as compared with similar patients treated with Dynamic Hip Screw (DHS). Materials and Methods The study included a total of 27 patients (17 males, 10 females) with unstable intertrochanteric fractures who were subjected to PFLCP treatment from March 2011 to November 2012 in one group. Another was a similar group of 35 patients treated with DHS from March 2008 to February 2010. Results of group 1 were compared with group 2. Detailed clinical conditions of all patients, duration of surgery, blood loss, length of incision and duration of image intensifier use were recorded. Patients were revisited at 6 weeks, 3 months, 6 months and 1 year after operation. Results were evaluated clinically by Harris hip Score and radiologically for fracture union. Progress of union and complications (limb shortening, varus collapse, cut out of femoral head screw and medialization of distal fragment) were recorded. Results Among 27 patients treated with PFLCP, one patient expired 6 week postoperatively and one patient lost to follow up, so 25 patients were evaluated for final outcome of which 23 (92%) showed union at follow up of 12 months. One patient developed bending of proximal screws and three developed varus collapse. Among the group treated with DHS, eight patients developed varus collapse, seven

  8. Anterior cervical pedicle screw and plate fixation using fluoroscope-assisted pedicle axis view imaging: a preliminary report of a new cervical reconstruction technique.

    Science.gov (United States)

    Yukawa, Yasutsugu; Kato, Fumihiko; Ito, Keigo; Nakashima, Hiroaki; Machino, Masaaki

    2009-06-01

    Anterior procedures in the cervical spine are feasible in cases having anterior aetiologies such as anterior neural compression and/or severe kyphosis. Halo vests or anterior plates are used concurrently for cases with long segmental fixation. Halo vests are bothersome and anterior plate fixation is not adequately durable. We developed a new anterior pedicle screw (APS) and plate fixation procedure that can be used with fluoroscope-assisted pedicle axis view imaging. Six patients (3 men and 3 women; mean age, 54 years) with anterior multisegmental aetiology were included in this study. Their original diagnoses comprised cervical myelopathy and/or radiculopathy (n = 4), posterior longitudinal ligament ossification (n = 1) and post-traumatic kyphosis (n = 1). All patients underwent anterior decompression and strut grafting with APS and plate fixation. Mean operative time was 192 min and average blood loss was 73 ml. Patients were permitted to ambulate the next day with a cervical collar. Local sagittal alignment was characterised by 3.5 degrees of kyphosis preoperatively, which improved to 6.8 degrees of lordosis postoperatively and 5.2 degrees of lordosis at final follow-up. Postoperative improvement and early bony union were observed in all cases. There was no serious complication except for two cases of dysphagia. Postoperative imaging demonstrated screw exposure in one screw, but no pedicle perforation. APS and plate fixation is useful in selected cases of multisegmental anterior reconstruction of cervical spine. However, the adequate familiarity and experience with both cervical pedicle screw fixation and the imaging technique used for visualising the pedicle during surgery are crucial for this procedure. PMID:19343377

  9. Stress analysis between“X”-shaped spine dynamic fixation and traditional pedicle screw fixation%“X”形弹性脊柱内固定与传统椎弓根内固定的应力分析

    Institute of Scientific and Technical Information of China (English)

    王宇; 梅继文; 穆尚强; 高峰; 黄锐

    2015-01-01

    背景:目前国内外许多学者研发了多种动态弹性脊柱内固定器,经过生物力学研究、动物实验及临床应用发现,尚无一种脊柱弹性内固定器得到临床上的普遍认可。  目的:比较自制“X”形弹性内固定器与传统椎弓根螺钉内固定的应力差异。  方法:根据成人脊柱影像学资料,分别建立“X”形弹性脊柱内固定器与传统椎弓根螺钉内固定系统三维有限元模型,比较两组模型在垂直压缩、屈、伸、侧屈、扭转时的力学差异。  结果与结论:两模型在垂直压缩状态应下的应力均小于屈、伸、侧屈及扭转状态下的应力;在垂直压缩、前屈、后伸、侧弯及旋转时,“X”形弹性脊柱内固定器的应力更多集中在“X”形连接棒上,而传统椎弓根螺钉内固定的应力更多集中在螺钉近棒段,且“X”形弹性脊柱内固定器螺钉所受应力明显小于传统椎弓根螺钉内固定(P<0.001)。表明“X”形弹性内固定器较传统椎弓根螺钉内固定系统更能分担螺钉应力,减少螺钉术后应力集中情况。%BACKGROUND:Many scholars have developed a variety of dynamic elastic spine fixator. After biomechanical research, animal experiments and clinical application found that no one elastic spine fixator was general y recognized clinical y. OBJECTIVE:To compare the stress difference between“X”-shaped spine dynamic fixation and traditional pedicle screw fixation. METHODS:Three-dimensional finite element models of“X”-shaped spine dynamic fixation and traditional pedicle screw fixation were established according to adult spine imaging data. Mechanical differences in vertical compression, flexion, extension, lateral bending and rotation were compared between the two groups. RESULTS AND CONCLUSION:The stress at vertical compression was lower than that at flexion, extension, lateral bending and rotation in both groups. The stress at

  10. Atlantoaxial arthrodesis using C1-C2 transarticular screw fixation in a case of Morquio syndrome

    OpenAIRE

    Kulkarni, Arvind G; Siddharth M Shah

    2011-01-01

    Prophylactic or therapeutic arthrodesis is recommended for atlantoaxial instability in Morquio syndrome. Occipitocervical fusion, the common approach for upper cervical fusion in Morquio syndrome sacrifices the movements at the occipitoatlantal joints. The use of C1-C2 transarticular screws for achieving C1-C2 arthrodesis, without compromising mobility at the occipitoatlantal joint in Morquio syndrome has not been reported. We report a case of Morquio syndrome with atlantoaxial instability an...

  11. Caput valgum associated with developmental dysplasia of the hip: management by transphyseal screw fixation

    OpenAIRE

    Torode, Ian P.; Young, Jeffrey L.

    2015-01-01

    Purpose A late finding of some hips treated for developmental dysplasia of the hip (DDH) is a growth disturbance of the lateral proximal femoral physis, which results in caput valgum and possibly osteoarthritis. Current treatment options include complete epiphysiodesis of the proximal femoral physis or a corrective proximal femoral osteotomy. Alternatively, a transphyseal screw through the inferomedial proximal femoral physis that preserves superolateral growth might improve this deformity. M...

  12. Fixation of femoral capital physeal fractures with 7.0 mm cannulated screws in five bulls

    International Nuclear Information System (INIS)

    Salter-Harris type I fractures of the femoral capital physis were repaired in five Holstein bulls with three 7.0 mm cannulated screws placed in lag fashion. Radiographically at months 7 to 10, the fractures were healed and there was periarticular bone production on the femoral necks and the dorsal acetabular rims. Four bulls had normal gaits, and one bull had muscle atrophy and barely detectable lameness

  13. Radiological Evaluation of the Initial Fixation between Cortical Bone Trajectory and Conventional Pedicle Screw Technique for Lumbar Degenerative Spondylolisthesis

    Science.gov (United States)

    Iwatsuki, Koichi; Ohnishi, Yu-Ichiro; Yoshimine, Toshiki

    2016-01-01

    Study Design Retrospective study. Purpose To compare initial fixation using the cortical bone trajectory (CBT) technique versus conventional pedicle screws (PS) in radiographs of postsurgical lumbar degenerative spondylolisthesis. Overview of Literature Few reports have documented the holding strength of CBT technique for spondylolisthesis cases. Methods From October 2009 to June 2014, 21 cases of degenerative spondylolisthesis were surgically treated in our institution. Ten were treated with conventional PS technique and 11 of with CBT technique. Mean lumbar lordosis and percent slippage were evaluated preoperatively, immediately after surgery, and 6 months and 1 year postoperatively using radiographs. We also investigated percent loss of slip reduction. Results There were statistically significant differences between preoperative percent slippage and postoperative slippage in both PS and CBT procedures over 1 year, and both techniques showed good slip reduction. On the other hand, lumbar lordosis did not change significantly in either the PS or CBT groups over 1 year. Conclusions CBT technique showed similarly good initial fixation compared with the PS procedure in the treatment of lumbar degenerative spondylolisthesis. PMID:27114765

  14. Supra-acetabular fixation and sacroiliac screws for treating unstable pelvic ring injuries: preliminary results from 20 patients☆

    Science.gov (United States)

    Guimarães, Rodrigo Pereira; de Góes Ribeiro, Arthur; Ulson, Oliver; de Ávila, Ricardo Bertozzi; Ono, Nelson Keiske; Polesello, Giancarlo Cavalli

    2016-01-01

    Objective To analyze the treatment results from 20 patients who underwent an alternative osteosynthesis method as definitive treatment for pelvic ring fractures. Methods A retrospective analysis was conducted on a series of 20 patients with pelvic ring fractures (Tile type C) and a high risk of postoperative infection, who were treated at Santa Casa de Misericórdia de São Paulo between August 2004 and December 2012. The patients underwent percutaneous supra-acetabular external fixation in association with cannulated 7.0 mm iliosacral screws. Results The patients’ mean age was 40 years (range 22–77 years) and the mean length of follow-up was 18.5 months (range 3–69 months). At the end of the treatment, ten patients (50%) were classified as having good results, nine patients (45%) had fair results and one patient (5%) did not have any improvement. Six patients presented complications, and paresthesia of the lateral femoral cutaneous nerve was the most frequent of these (two patients). Conclusion Supra-acetabular external fixation in association with iliosacral percutaneous osteosynthesis is a good definitive treatment method for patients with a high risk of postoperative infection. PMID:27069879

  15. Results of screw fixation combined with cortical drilling for treatment of dorsal cortical stress fractures of the third metacarpal bone in 56 Thoroughbred racehorses

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate screw fixation with cortical drilling as a surgical treatment for dorsal cortical stress fractures of MCIII in the Thoroughbred racehorse. Details of age, sex, limb affected, fracture assessment, and post operative recommendations were obtained from medical records and radiographs. Fracture healing was assessed radiographically at the time of screw removal. Performance evaluation was determined from race records obtained from The Jockey Club Information System, Lexington, Kentucky. Fifty-six Thoroughbred racehorses were treated surgically for stress fracture of MCIII with screw fixation and cortical drilling. Stress fractures occurred primarily in the left front limb of the male 3-year-olds, in the dorsolateral cortex of the middle third of MCIII. Ninety-seven percent of the fractures travelled in a dorsodistal to palmaroproximal direction. Median period to screw removal was 2.0 months. Evaluation at time of screw removal revealed 98% of single stress fractures of the left front limb were healed radiographically. Median period to resume training was 2.75 months (single stress fractures); median period to race was 7.62 months. There was no statistically significant difference in earnings/start before and after surgical intervention. Of the 63 fractures treated, two recurred. There were no catastrophic failures, and no incisional infections

  16. Clinical results of the re-fixation of a Chevron olecranon osteotomy using an intramedullary cancellous screw and suture tension band.

    Science.gov (United States)

    Wagener, Marc L; Dezillie, Marleen; Hoendervangers, Yvette; Eygendaal, Denise

    2015-04-01

    Exposure of the distal humerus in case of an articular fracture is often performed through a Chevron osteotomy of the olecranon. Several options have been described for re-fixation of the Chevron osteotomy. Pull-out of the hard-wear is often seen as complication. In this study, an evaluation of the re-fixation of the Chevron osteotomy through a cancellous screw and suture tension band was performed. The data of 19 patients in whom a Chevron osteotomy was re-fixated with a cancellous screw in combination with a suture tension band were used. Evaluation was performed by assessment of the post-operative X-rays and documentation of complications. In all 19 cases, evaluation of the post-operative X-rays showed complete consolidation without dislocation or other complications. Re-fixation of a Chevron osteotomy of the olecranon with a large cancellous screw with a suture tension band provides adequate stability to result in proper healing of the osteotomy in primary cases when early post-operative mobilisation is allowed. Complications as pull-out of the hard-wear were not reported. PMID:25697273

  17. A novel computed method to reconstruct the bilateral digital interarticular channel of atlas and its use on the anterior upper cervical screw fixation

    Science.gov (United States)

    Wu, Ai-Min; Wang, Wenhai; Xu, Hui; Lin, Zhong-Ke; Yang, Xin-Dong; Wang, Xiang-Yang; Xu, Hua-Zi

    2016-01-01

    Purpose. To investigate a novel computed method to reconstruct the bilateral digital interarticular channel of atlas and its potential use on the anterior upper cervical screw fixation. Methods. We have used the reverse engineering software (image-processing software and computer-aided design software) to create the approximate and optimal digital interarticular channel of atlas for 60 participants. Angles of channels, diameters of inscribed circles, long and short axes of ellipses were measured and recorded, and gender-specific analysis was also performed. Results. The channels provided sufficient space for one or two screws, and the parameters of channels are described. While the channels of females were smaller than that of males, no significant difference of angles between males and females were observed. Conclusion. Our study demonstrates the radiological features of approximate digital interarticular channels, optimal digital interarticular channels of atlas, and provides the reference trajectory of anterior transarticular screws and anterior occiput-to-axis screws. Additionally, we provide a protocol that can help make a pre-operative plan for accurate placement of anterior transarticular screws and anterior occiput-to-axis screws. PMID:26925345

  18. Fracture union and complication following internal fixation of clavicle by plate and screw

    OpenAIRE

    Bishnu Prasad Patro; Saroj Kumar Patra; Subrat Mohapatra

    2016-01-01

    Background: Among all long bones clavicle is the only bone placed horizontally and has membranous ossification. Clavicle fractures accounting for about 2.6% of total body fractures and 34% to 45% of total shoulder girdle injuries in adults. Most fractures occur in middle third of clavicle and common in young male patients. It has wide range of management from conservative to variant internal fixation. Each procedure has its own outcome and complications. We tried to find out the outcome and c...

  19. Chinese traditional medicine rehabilitative treatment of femoral neck fracture after screw thread needle internal fixation%螺纹针内固定术后中药康复治疗股骨颈骨折

    Institute of Scientific and Technical Information of China (English)

    高广升; 李凤辉

    2001-01-01

    @@ Background:Femoral neck fracture is one of common and severe injury in old people. We utilize transcutaneous Screw thread needle internal fixation treat it, cooperated with Chinese medicine treatment, and gained good effects.

  20. Role of valgus osteotomy and fixation with dynamic hip screw and 120° double angle barrel plate in the management of neglected and ununited femoral neck fracture in young patients

    OpenAIRE

    Khan, Abdul Qayyum; Khan, Mohammad Shahnawaz; Sherwani, Mohammed Khalid Anwar; Agarwal, Rahul

    2009-01-01

    Background Head preservation is the mainstay of management in younger patients with neglected or ununited intracapsular fracture neck of femur. Very few reports have dealt with the results of valgus intertrochanteric osteotomy and fixation with dynamic hip screw in such cases. In this prospective study, we have tried to evaluate the role of valgus osteotomy and fixation with dynamic hip screw and 120° double angle barrel plate in neglected or ununited intracapsular fracture neck of femur in p...

  1. Segmental pedicle screw fixation for a scoliosis patient with post-laminectomy and post-irradiation thoracic kyphoscoliosis of spinal astrocytoma

    International Nuclear Information System (INIS)

    Spinal deformity is an important clinical manifestation after surgery for spinal cord tumors. One-third of patients who receive laminectomies and irradiation of the spinal column develop scoliosis, kyphosis, or kyphoscoliosis. Recent reports indicate good results after scoliosis surgery using segmental pedicle screws and a navigation system, but these reported studies have not included surgery for post-laminectomy kyphosis. Hooks and wires are ineffective in such patients who undergo laminectomy, and there are also high perioperative risks with insertion of pedicle screws because landmarks have been lost. Here, we report on the 5-year follow-up of a 13-year-old male patient with post-laminectomy and post-irradiation thoracic kyphoscoliosis after surgical treatment of spinal astrocytoma. Posterior segmental pedicle screw fixation was performed safely using a computer-assisted technique. The authors present the first case report for treatment of this condition using a navigation system. (author)

  2. Limited Unilateral Decompression and Pedicle Screw Fixation with Fusion for Lumbar Spinal Stenosis with Unilateral Radiculopathy: A Retrospective Analysis of 25 Cases

    OpenAIRE

    Zhang, Li; Miao, Hai-xiong; Wang, Yong; Chen, An-fu; Zhang, Tao; Xiao-guang LIU

    2015-01-01

    Objective Lumbar spinal stenosis is conventionally treated with surgical decompression. However, bilateral decompression and laminectomy is more invasive and may not be necessary for lumbar stenosis patients with unilateral radiculopathy. We aimed to report the outcomes of unilateral laminectomy and bilateral pedicle screw fixation with fusion for patients with lumbar spinal stenosis and unilateral radiculopathy. Methods Patients with lumbar spinal stenosis with unilateral lower extremity rad...

  3. Novel pedicle screw and plate system provides superior stability in unilateral fixation for minimally invasive transforaminal lumbar interbody fusion: an in vitro biomechanical study.

    Directory of Open Access Journals (Sweden)

    Jie Li

    Full Text Available This study aims to compare the biomechanical properties of the novel pedicle screw and plate system with the traditional rod system in asymmetrical posterior stabilization for minimally invasive transforaminal lumbar interbody fusion (MI-TLIF. We compared the immediate stabilizing effects of fusion segment and the strain distribution on the vertebral body.Seven fresh calf lumbar spines (L3-L6 were tested. Flexion/extension, lateral bending, and axial rotation were induced by pure moments of ± 5.0 Nm and the range of motion (ROM was recorded. Strain gauges were instrumented at L4 and L5 vertebral body to record the strain distribution under flexion and lateral bending (LB. After intact kinematic analysis, a right sided TLIF was performed at L4-L5. Then each specimen was tested for the following constructs: unilateral pedicle screw and rod (UR; unilateral pedicle screw and plate (UP; UR and transfacet pedicle screw (TFS; UP and TFS; UP and UR.All instrumented constructs significantly reduced ROM in all motion compared with the intact specimen, except the UR construct in axial rotation. Unilateral fixation (UR or UP reduced ROM less compared with the bilateral fixation (UP/UR+TFS, UP+UR. The plate system resulted in more reduction in ROM compared with the rod system, especially in axial rotation. UP construct provided more stability in axial rotation compared with UR construct. The strain distribution on the left and right side of L4 vertebral body was significantly different from UR and UR+TFS construct under flexion motion. The strain distribution on L4 vertebral body was significantly influenced by different fixation constructs.The novel plate could provide sufficient segmental stability in axial rotation. The UR construct exhibits weak stability and asymmetrical strain distribution in fusion segment, while the UP construct is a good alternative choice for unilateral posterior fixation of MI-TLIF.

  4. Iliosacral screw fixations of posterior pelvic ring injuries guided by TAC scan

    International Nuclear Information System (INIS)

    An observational and descriptive study of a series was conducted between February 2001 and November 2002 at the departments of orthopedics and traumatology of the hospital de San Jose, Clinica Palermo and Fundacion Santa Fe de Bogota. 10 patients (12 fractures) with unstable lesions of the pelvic ring, on whom TAC guided percutaneous fixation of the posterior portion of the pelvic ring was performed. Six of the patients were female (60%) and four were male (40%) and average age 33.4 years (16 to 54 years)

  5. The concept of valgus under reduction in fixation of displaced trochanteric femoral fractures with sliding hip screw.

    Science.gov (United States)

    Latif, Abdul; Mukherjee, Kuladip; Ranjan, Amit Kumar; Mukhopadhyay, Kiran Kumar

    2013-12-01

    Sixty-six patients (male 30, female 36) with displaced trochanteric fractures (according to AO classification = A1.2, A1.3 A2 and A3 groups) have been studied during the period November 2011 to September 2013. Displaced stable fractures also have been included because in grossly osteoporotic elderly patients, this may lead to gross uncontrolled collapse and act like unstable fracture and it has fixation failure rate of 1-9%. Mean age of the patients was 8.5 years. DHS was used for the patients with intact lateral cortex and used DCS for the fractures with comminuted lateral cortex extending up to vastus ridge and also in A3 types. The screw placement was inferior to central in AP view, and central to posterior in lateral view. In AP view under reduction was done with slight lateralisation and upward displacement of distal fragment and fixed with DHS/DCS with affected limb in abduction 30 to 40 degree to achieve valgus angle of about 160-170. In lateral view neck shaft angle was maintained to 160-180 degree, on higher side, avoiding retroversion. All the parameters of fixation failure like varus displacement, retroversion, external rotation, medialisation, cut out, collapse and shortening of limb, pullout side plate and implant failure have been studied. Only the patients treated with valgus under-reduction have been included in this study. We conclude that under-reduction in valgus position gives excellent posteromedical stability as it provides controlled collapse as the calcar fragment is abutting against the medial femoral shaft (as in Weyne County reduction) and also prevents shortering by valgus reduction (Parker). PMID:25154155

  6. Segmental correction of adolescent idiopathic scoliosis by all-screw fixation method in adolescents and young adults. minimum 5 years follow-up with SF-36 questionnaire

    Directory of Open Access Journals (Sweden)

    Yu Ching-Hsiao

    2012-02-01

    Full Text Available Abstract Background In our institution, the fixation technique in treating idiopathic scoliosis was shifted from hybrid fixation to the all-screw method beginning in 2000. We conducted this study to assess the intermediate -term outcome of all-screw method in treating adolescent idiopathic scoliosis (AIS. Methods Forty-nine consecutive patients were retrospectively included with minimum of 5-year follow-up (mean, 6.1; range, 5.1-7.3 years. The average age of surgery was 18.5 ± 5.0 years. We assessed radiographic measurements at preoperative (Preop, postoperative (PO and final follow-up (FFU period. Curve correction rate, correction loss rate, complications, accuracy of pedicle screws and SF-36 scores were analyzed. Results The average major curve was corrected from 58.0 ± 13.0° Preop to 16.0 ± 9.0° PO(p p = 0.12 FFU. This revealed a 72.7% correction rate and a correction loss of 2.4° (3.92%. The thoracic kyphosis decreased little at FFU (22 ± 12° to 20 ± 6°, (p = 0.25. Apical vertebral rotation decreased from 2.1 ± 0.8 PreOP to 0.8 ± 0.8 at FFU (Nash-Moe grading, p Conclusion Follow-up more than 5 years, the authors suggest that all-screw method is an efficient and safe method.

  7. The Use of Posterior Short Segment Screw Fixation and Balloon Kyphoplasty in the Surgical Treatment of Traumatic Vertebral Fracture: A Case Report

    Directory of Open Access Journals (Sweden)

    Sevim Ondul

    2012-04-01

    Full Text Available Surgical treatments for the fracture of the spine are frequently used in clinical practice. Posterior spine stabilization with transpedicular screw fixation is one of the surgical treatment methods in the surgical treatment of spinal fractures. A 48-year old male patient was admitted to our hospital with a diagnosis of the L1 compression fracture resulting from traumatic injury. Posterior transpedicular screws were placed at one level above and one level below of the fractured vertebrate. Anterior column of the fractured vertebrate was strengthened with balloon kyphoplasty application. The system was completed with the placement of transverse rods. Fusion with allograft was performed. According to the ASIA neurological grading system, the patient was assessed as Grade E. 10 cm skin and fascia incision was done. Operation time of about 70 minutes and blood loss was less than 100 cc. The patient was mobilized on the first day of surgery and was discharged from the hospital on the third day after the surgery. Short segment transpedicular fixation on the one level above and one level below of the fractured vertebrate together with balloon kyphoplasty on the corpus of the fractured vertebrate may be used as a minimally invasive surgical treatment in such kind of injuries. The advantages are short duration of hospital stay, less blood loss, providing early mobilization, and a reliable method for fixation and stabilization. In this article, a case with traumatic fracture that fixed and stabilized with short segment transpedicular screw placement and balloon kyphoplasty application was presented.

  8. CT morphometric analysis to determine the anatomical basis for the use of transpedicular screws during reconstruction and fixations of anterior cervical vertebrae.

    Directory of Open Access Journals (Sweden)

    Chun Chen

    Full Text Available BACKGROUND: Accurate placement of pedicle screw during Anterior Transpedicular Screw fixation (ATPS in cervical spine depends on accurate anatomical knowledge of the vertebrae. However, little is known of the morphometric characteristics of cervical vertebrae in Chinese population. METHODS: Three-dimensional reconstructions of CT images were performed for 80 cases. The anatomic data and screw fixation parameters for ATPS fixation were measured using the Mimics software. FINDINGS: The overall mean OPW, OPH and PAL ranged from 5.81 to 7.49 mm, 7.77 to 8.69 mm, and 33.40 to 31.13 mm separately, and SPA was 93.54 to 109.36 degrees from C3 to C6, 104.99 degrees at C7, whereas, 49.00 to 32.26 degrees from C4 to C7, 46.79 degrees at C3 (TPA. Dl/rSIP had an increasing trend away from upper endplate with mean value from 1.87 to 5.83 mm. Dl/rTIP was located at the lateral portion of the anterior cortex of vertebrae for C3 to C5 and ipsilateral for C6 to C7 with mean value from -2.70 to -3.00 mm, and 0.17 to 3.18 mm. The entrance points for pedicular screw insertion for C3 to C5 and C6 to C7 were recommended -2∼-3 mm and 0-4 mm from the median sagittal plane, respectively, 1-4 mm and 5-6 mm from the upper endplate, with TPA being 46.79-49.00 degrees and 40.89-32.26 degrees, respectively, and SPA being 93.54-106.69 degrees and 109.36-104.99 degrees, respectively. The pedicle screw insertion diameter was recommended 3.5 mm (C3 and C4, 4.0 mm (C5 to C7, and the pedicle axial length was 21-24 mm for C3 to C7 for both genders. However, the ATPS insertion in C3 should be individualized given its relatively small anatomical dimensions. CONCLUSIONS: The data provided a morphometric basis for the ATPS fixation technique in lower cervical fixation. It will help in preoperative planning and execution of this surgery.

  9. New Technique for C1 Double-Door Laminoplasty Using Allograft Spacers and Titanium Miniplate Screw Fixation: Technical Report.

    Science.gov (United States)

    Kim, Seok Woo; Lee, Jae-Hoo; Lee, Ho-Won; Oh, Jae-Keun; Kwak, Yoon-Hae

    2016-03-01

    Although conventional C1 laminectomy is the gold standard for decompression at the atlas, it provides little space for the bone graft to fuse. The fusion area can be extended cranially up to the occipital bone, but it requires sacrificing the function of the craniocervical junction. To date, no reports have focused on surgical techniques for successful decompression and fusion without disruption of the posterior C1 arch while providing enough room for the bone graft to fuse. This study introduces a new technique for C1-C2 fusion and C1 double-door laminoplasty in patients with C1-C2 instability, canal stenosis, and cervical spondylotic myelopathy. A 66-year-old man who had undergone C1-C2 fusion at a local clinic 2 years earlier visited our hospital due to progressive myelopathy. A preoperative computed tomography (CT) scan showed the tip of the odontoid process, extending into the spinal canal. On the axial view of T2-weighted magnetic resonance images, the tip of the odontoid process significantly compressed the spinal cord on the left side. The atlantodental interval was 7 mm on radiography; however, C1-C2 instability was not evident on flexion-extension X-rays due to the previous screw fixation. The patient underwent C1-C2 decompression and fusion surgery with our new surgical technique. The segmental screws were repositioned at C1 and C2, and we performed C1 double-door laminoplasty augmented with an allograft spacer and a titanium miniplate. A marked reduction was seen at postoperative radiograph and CT scan. Neurologic symptoms were relieved dramatically after surgery without any discomfort. No complications were noted. We introduced a new surgical technique that allows bone grafting, decompression, and fusion to be performed without disruption of the posterior C1 arch in the event of C1-C2 canal stenosis combined with instability. This technique may be indicated for other conditions that cause instability and stenosis at the C1-C2 area. PMID:26689563

  10. Two-level anterior lumbar interbody fusion with percutaneous pedicle screw fixation. A minimum 3-year follow-up study

    International Nuclear Information System (INIS)

    The clinical and radiological outcomes of two-level anterior lumbar interbody fusion (ALIF) with percutaneous pedicle screw fixation (PSF) were evaluated in 24 consecutive patients who underwent two level ALIF with percutaneous PSF for segmental instability and were followed up for more than 3 years. Clinical outcomes were assessed using a visual analogue scale (VAS) score and the Oswestry Disability Index (ODI). Sagittal alignment, bone union, and adjacent segment degeneration (ASD) were assessed using radiography and magnetic resonance imaging. The mean age of the patients at the time of operation was 56.3 years (range 39-70 years). Minor complications occurred in 2 patients in the perioperative period. At a mean follow-up duration of 39.4 months (range 36-42 months), VAS scores for back pain and leg pain, and ODI score decreased significantly (from 6.5, 6.8, and 46.9% to 3.0, 1.9, and 16.3%, respectively). Clinical success was achieved in 22 of the 24 patients. The mean segmental lordosis, whole lumbar lordosis, and sacral tilt significantly increased after surgery (from 25.1deg, 39.2deg, and 32.6deg to 32.9deg, 44.5deg, and 36.6deg, respectively). Solid fusion was achieved in 21 patients. ASD was found in 8 of the 24 patients. No patient underwent revision surgery due to nonunion or ASD. Two-level ALIF with percutaneous PSF yielded satisfactory clinical and radiological outcomes and could be a useful alternative to posterior fusion surgery. (author)

  11. 骨水泥强化椎弓根螺钉固定L1压缩性骨折:与单纯椎弓根螺钉固定的比较%Pedicle screw fixation with bone cementversus pedicle screw fixation alone for L1 compression fractures

    Institute of Scientific and Technical Information of China (English)

    亚力坤•亚森

    2015-01-01

    背景:椎体成形术与椎弓根螺钉内固定都是胸腰椎骨折的有效修复方案,但胸腰椎压缩性骨折内固定取出后脊柱角度丢失是较为常见的并发症,经皮椎体成形术可能是预防脊柱角度丢失的较好选择。  目的:观察骨水泥强化椎弓根螺钉置入内固定修复L1压缩性骨折的临床疗效及并发症,并与单纯椎弓根螺钉内固定比较。  方法:纳入L1压缩性骨折患者76例,根据内固定修复方案分为两组,经皮椎体成形组40例行骨水泥联合椎弓根螺钉置入内固定治疗,单纯椎弓根内固定组36例仅行椎弓根螺钉置入内固定治疗。比较两组的修复效果,置入后即刻、置入后3,6个月以伤椎为中心进行MRI检查测量Cobb角、伤椎椎体前缘高度,同时记录目测类比评分;另外了解有无内固定松动断裂。  结果与结论:两组患者随访6个月内均获骨性愈合,无螺钉松动、折断。两组置入后6个月损伤节段后凸Cobb角、伤椎椎体前缘高度均较置入前明显改善(P0.05)。表明应用骨水泥强化椎弓根螺钉内固定及椎弓根钉内固定修复L1压缩性均可获得满意复位,重建椎体高度。但抗压稳定性结果表明应用骨水泥强化椎弓根螺钉内固定的固定效果更好一些,未见短期断钉、矫正丢失等并发症,椎体骨水泥灌注可提高椎弓根螺钉置入后的稳定性。%BACKGROUND:Vertebroplasty and edicle screw fixation are effective repair methods for thoracolumbar fractures. Spine angle loss is a more common complication after removal of implant for thoracolumbar compression fractures. Percutaneous vertebroplasty may be a better choice for preventing spine angle loss. OBJECTIVE:To investigate the clinical curative effect and complication of pedicle screw fixation with bone cement for repair of L1 compression fractures, and to compare with pedicle screw fixation alone. METHODS: A total

  12. Role of Joshi's external stabilization system with percutaneous screw fixation in high-energy tibial condylar fractures associated with severe soft tissue injuries

    Institute of Scientific and Technical Information of China (English)

    Ashish Kumar Gupta; Rahul Sapra; Rakesh Kumar; Som Prakash Gupta; Devwart Kaushik; Sahil Gaba; Mahesh Chand Bansal

    2015-01-01

    Purpose: The treatment of high-energy tibial condylar fractures which are associated with severe sott tissue injuries remains contentious and challenging.In this study, we assessed the results of Joshi's external stabilization system (JESS) by using the principle of ligamentotaxis and percutaneous screw fixation for managing high-energy tibial condylar fractures associated with severe soft tissue injuries.Methods: Between June 2008 and June 2010, 25 consecutive patients who were 17-71 years (mean, 39.7), underwent the JESS fixation for high-energy tibial condylar fractures associated with severe soft tissue injuries.Out of 25 patients, 2 were lost during follow-up and in 1 case early removal of frame was done, leaving 22 cases for final follow-up.Among them, 11 had poor skin condition with abrasions and blisters and 2 were open injuries (Gustilo-Anderson grade Ⅰ & Ⅱ).The injury mechanisms were motor vehicle accidents (n =19), fall from a height (n =2) and assault (n =1).The fractures were classified according to Schatzker classification system.Results: There were 7 type-Ⅴ, 14 type-Ⅵ and 1 type-Ⅳ Schatzker's tibial plateau fractures.The average interval between the injury and surgery was 6.8 days (range 2-13).The average hospital stay was 13 days (range, 7-22).The average interval between the surgery and full weight bearing was 13.6 weeks (range 11-20).The average range of knee flexion was 121° (range 105°-135°).The normal extension of the knee was observed in 20 patients, and an extensor lag of 5°-8° was noted in 2 patients.The complications included superficial pin tract infections (n =4) with no knee stiffness.Conclusion: JESS with lag screw fixation combines the benefit of traction, external fixation, and limited internal fixation, at the same time as allowing the ease of access to the soft tissue for wound checks, pin care, dressing changes, measurement of compartment pressure, and the monitoring of the neurovascular status.In a nutshell, JESS

  13. Avaliação dos resultados da tenodese artroscópica do bíceps, utilizando-se parafuso de interferência bioabsorvível Evaluation of arthroscopic tenodesis of the biceps using a bioabsorbable interference screw

    Directory of Open Access Journals (Sweden)

    Sérgio Luiz Checchia

    2007-08-01

    Full Text Available OBJETIVO: Avaliar os resultados obtidos com a realização da tenodese da cabeça longa do bíceps (CLB pela técnica artroscópica, com a utilização de parafuso de interferência bioabsorvível biotenodese Arthrex®. MÉTODOS: Entre março de 2004 e abril de 2005, 16 ombros de 16 pacientes foram submetidos a tenodese da CLB com essa técnica. O seguimento mínimo foi de 12 meses, com média de 19,5 meses. A idade variou de 32 a 69 anos, com média de 56,1 anos. Houve predomínio do sexo masculino em 75% dos casos. O membro dominante foi acometido em 62,5% dos pacientes. Foi encontrada lesão parcial da CLB em 75% dos pacientes e instabilidade em 25%. Houve associação com lesão do manguito rotador (LMR em 93,75% dos casos. A avaliação clínica foi feita por meio dos critérios da University of California at Los Angeles (UCLA. RESULTADOS: Observamos excelentes resultados em todos os casos. Não foi observado em nenhum caso sinal de retração do músculo bíceps (sinal do Popeye, caracterizando soltura da tenodese. CONCLUSÃO: A tenodese da CLB pela técnica artroscópica, com a utilização de parafuso de interferência bioabsorvível biotenodese Arthrex® mostrou-se uma técnica eficiente para o tratamento das alterações da CLB.OBJECTIVE: To evaluate results obtained with arthroscopic tenodesis of the long head of the biceps (LHB using a bioabsorbable interference screw Arthrex® biotenodesis. METHODS: Between March 2004 and April 2005, 16 shoulders of 16 patients were submitted to LHB tenodesis using this technique. Minimum follow-up was 12 months, with a mean of 19.5 months. Age ranged from 32 to 69 years, mean of 56.1 years. Male patients prevailed, with 75% of the cases. The dominant limb was involved in 62.5% of the patients. Partial lesion of the LHB was found in 75% of the patients, and instability in 25%. Association to rotator cuff lesion (RCL was found in 93.75% of the cases. Clinical evaluation was based on the University of

  14. C1-C2 transarticular screw fixation for atlantoaxial instability due to rheumatoid arthritis: a seven-year analysis of outcome.

    LENUS (Irish Health Repository)

    Nagaria, Jabir

    2009-12-15

    STUDY DESIGN.: Observational study. Retrospective analysis of prospectively collected data. OBJECTIVE.: The purpose of this article was to report long-term (minimum 7 years) clinical and radiologic outcome of our series of patients with Rheumatoid Arthritis who underwent transarticular screw fixation to treat atlantoaxial subluxation. SUMMARY OF BACKGROUND DATA.: The indications for intervention in patients with atlantoaxial instability are pain, myelopathy, and progressive neurologic deficit. The various treatment options available for these patients are isolated C1-C2 fusion, occipitocervical fusion with or without transoral surgery. Review of current literature suggests that C1-C2 transarticular screw fixation has significant functional benefits, although there is discrepancy in this literature regarding improvement in function following surgery. METHODS.: Myelopathy was assessed using Ranawat myelopathy score and Myelopathy Disability Index. Pain scores were assessed using Visual Analogue Scale. The radiologic imaging was assessed and the following data were extracted; atlanto-dens interval, space available for cord, presence of signal change on T2 weighted image, and fusion rates. RESULTS.: Thirty-seven patients, median age 56, were included in the study. Average duration of neck symptoms was 15.8 months. Average duration of rheumatoid arthritis before surgery was 20.6 years. Preoperative symptoms: suboccipital pain in 26 patients; neck pain, 32; myelopathy, 22; and 5 were asymptomatic. After surgery: suboccipital pain, 2; neck pain, 3; and myelopathy, 10. Ninety percent patients with neck and suboccipital pain improved after surgery in their Visual Analogue pain scores, with all of them having >50% improvement in VAS scores (6.94-2.12 [P < 0.05]).Preoperative Ranawat grade was as follows: grade 1 in 15 patients, grade 2 in 7, and grade 3a in 14, grade 3b in 1.After surgery: grade 1 in 27 patients, grade 2 in 7, grade 3a in 1, and grade 3b in 2. The mean

  15. Biomechanical and finite element analyses of bone cement-Injectable cannulated pedicle screw fixation in osteoporotic bone.

    Science.gov (United States)

    Liu, Yaoyao; Xu, Jianzhong; Sun, Dong; Luo, Fei; Zhang, Zehua; Dai, Fei

    2016-07-01

    The objectives of this study were to investigate the safety and biomechanical stability of a polymethylmethacrylate (PMMA)-augmented bone cement-injectable cannulated pedicle screw (CICPS) in cancellous bone model, and to analyze the stress distribution at the screw-cement-bone interface. The OMEGA cannulated pedicle screw (OPS) and conventional pedicle screw (CPS) were used as control groups. Safety of the CICPS was evaluated by the static bending and bending fatigue tests. Biomechanical stability was analyzed by the maximum axial pullout strength and maximum torque tests. Stress distribution at the screw-cement-bone interface was analyzed by the finite element (FE) method. The CICPS and CPS produced statistically similar values for bending stiffness, bending structural stiffness, and bending yield moment. The maximum pullout force was 53.47 ± 8.65 N in CPS group, compared to 130.82 ± 7.32 N and 175.45 ± 43.01 N in the PMMA-augmented OPS and CICPS groups, respectively (p screw-cement-bone interface in the CICPS group. In conclusion, PMMA-augmentation with CICPS may be a potentially useful method to increase the stability of pedicle screws in patients with osteoporosis. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 960-967, 2016. PMID:25976272

  16. Minimally invasive pedicle screw fixation utilizing O-arm fluoroscopy with computer-assisted navigation: Feasibility, technique, and preliminary results

    OpenAIRE

    Park, Paul; Foley, Kevin T; Cowan, John A; Marca, Frank La

    2010-01-01

    Background: Pedicle screw misplacement is relatively common, with reported rates ranging up to 42%. Although computer-assisted image guidance (CaIG) has been shown to improve accuracy in open spinal surgery, its use in minimally invasive procedures has not been as well evaluated. We present our technique and review the results from a cohort of patients who underwent minimally invasive lumbar pedicle screw placement utilizing the O-arm imaging unit in conjunction with the StealthStation Treon ...

  17. Smallness kerf pedicle screw internal fixation cure thoracolumbar fracture%小切口椎弓根钉棒内固定治疗胸腰椎骨折

    Institute of Scientific and Technical Information of China (English)

    胡红耘

    2009-01-01

    Objective Smallness kerr rout of retreat pedicle screw posting restoration fixing cure thoracolum-bar fracture. Methods Versus 12 example thoracolumbar fracture adopt smallness keff micro-wound rout of retreat pedicle screw posting restoration fixing technology. Results 12 example fracture patient follow-up survey 8 loaf months to 2 year, average long dozen month, fracture restoration satisfaction, pedicle screw position all right, without height lost, without looseness,lapse sever natl. Conclusion Thoracolumbar fracture met pedicle screw push off resto-ration internal fixation, reestablish physiologic protrusion, operation kerf smallness, esthetic appearance, hemorrhage fewness wound reaction smallness, in favor of skill post-recovery.%目的 探讨椎弓根钉棒置入复位固定治疗胸腰椎骨折的手术入路方法.方法 对12例胸腰椎骨折的病例采用小切口微创后路椎弓根钉棒置入复位固定技术.结果 12例骨折患者随访8个月至2年,平均13个月,骨折复位满意,椎弓根钉棒位置良好,无高度丢失、无松动、失效、断钉.结论 胸腰椎骨折可选择后路小切口术式行椎弓根钉棒撑开复位内固定,重建生理前突,手术切口小、美观、出血少、创伤反应小,有利于术后恢复.

  18. A Prospective Study on Radiological and Functional Outcome of Displaced Tongue Type Intra-Articular Calcaneal Fractures Treated by Percutaneous Screw Fixation

    Science.gov (United States)

    Hegde, Anoop; Mathias, Lawrence John; Shetty, Vikram; Shetty, Ashwin

    2016-01-01

    Introduction Calcaneal fractures have posed a challenge to orthopaedic surgeon for many years. The major problem is to reconstruct the fracture and improve healing of the fracture and also the surrounding tissues. Anatomic restoration of the three-dimensional anatomy of the calcaneum is the goal of surgical management of calcaneal fractures. Over the years, various techniques have been developed to accomplish this goal. Aim To determine the functional outcome in displaced tongue-type calcaneal fracture treated by percutaneous screw fixation. Materials and Methods A prospective study was conducted from October 2012 and September 2014. A total of 23 patients with intra-articular ‘tongue type’ calcaneal fractures were included in the study. Complete clinical and radiological evaluation was done. The surgical procedure encompassed closed reduction and fixation with two criss-cross 6.5 mm cannulated cancellous across the fracture site under fluoroscopic guidance. Postoperatively, on day three ankle and toe mobilization was begun. Non-weight bearing crutch mobilization was begun on postoperative day three. Reviews were done at 6 weeks, 12 weeks and 24 weeks postoperatively. At 6 weeks partial weight bearing mobilization was started. Full weight bearing was begun at 12 weeks. The patient was finally reviewed at 24 weeks and assessment of ankle function was done as per the Maryland foot scoring system. Radiographs were compared and preoperative and postoperative Gissane’s and Bohler’s angles were also compared. The results were analysed as per descriptive statistics (frequency, percentage). The complications noted were documented. Results Of the 23 patients under the study, three had excellent results with mean score of 90, 17 had good results with mean score of 82.94 and three had fair results with mean score of 74. Only one patient had subtalar arthritis as a complication. No other complications were seen. Conclusion Percutaneous screw fixation of tongue type

  19. 钉道强化提高椎弓根螺钉固定强度的生物力学研究%Biomechanical study of the improvement of pedicle screw fixation with application of local screw tunnel augmentation technique and expansive pedicle screws

    Institute of Scientific and Technical Information of China (English)

    杨彬奎; 雷伟; 王军; 吴子祥; 刘达; 李运明

    2008-01-01

    Objective To evaluate the improvement of pedicle screw fixation with the application of local screw tunnel augmentation technique and expansive pediele screws.Methods Injecting CaSO4 bone cement into the perine of pediele screw tunnel by new design instruments in order to augment the screw tunnel.Twenty lumbar vertebrae from five frozen human spine specimens were divided into 10 blocks by randomized block design.Four fixation methods were applied:group A(common pedicle screws),group B(common pedicle screws+local screw tunnel augmentation technique),group C(expansive pedicle screws+local screw tunnel augmentation technique),group D(common pedicle screws+CaSO4 bone cement filled into pedicle screw tunnels).Four fixation methods were performed in four screw tunnels of each two blocks at random.And then the maximum axial pullout strength(Fmax)and energy absorbed were measured for comparison.Results Mean values of the Fmax and energy absorbed of group C or D were statistically significantly greater than those of group A(P<0.01)and group B(P<0.05).Mean values of the Fmax and energy absorbed of group B were also statistically significantly greater than those of group A(P<0.01).There was no statistical significant difference between group C and group D(P>0.05).Conclusion The pedicle screw fixation might be improved with the application of local screw tunnel augmentation technique and it might be even finner if combined with expansive pedicle screws.%目的 评价椎弓根钉道局部强化技术及其结合膨胀式椎弓根螺钉提高椎弓根螺钉固定强度的效果.方法 通过自行设计及加工的钉道局部强化装置,向钉道周壁点状注入CaSO4骨水泥以强化椎弓根钉道.5具新鲜冻存人体脊柱标本,每具随机选取4个腰椎共20个腰椎标本,采用随机区组设计方法分为10个区组.设计四种固定方法:A组(普通椎弓根螺钉)、B组(普通椎弓根螺钉+钉道局部强化)、C组(膨胀式椎弓根螺钉+钉

  20. Clinical effects of posterior pedicle screw fixation on spinal deformity in growing period: a report of 360 cases

    Directory of Open Access Journals (Sweden)

    Zheng-lei WANG

    2011-08-01

    Full Text Available Objective To observe the effect of a new kind of pedicle screw frame system with sliding terminus and locked middle segment on spinal deformity in growing period.Methods Three hundred and sixty patients in growing period were involved in the present study,and among them 82 were suffering from congenital scoliosis,218 idiopathic scoliosis and 60 kyphosis.All the patients were treated with the pedicle screw frame system with sliding terminus and locked middle segment.The treatment effects and postoperative complications were observed,and the Cobb angle before and after the operation was compared.Results The Cobb angle of 300 scoliosis patients was corrected from 53°±3° to 8°±2°,and the Cobb angle of 60 kyphosis patients was corrected from 60°±2° to 25°±3°,and the corrective effect was satisfactory.The correction rate of patients with Cobb angle ≤50° was 80%.Two hundred and ten patients were followed-up for 1 to 6 years,and the longitudinal growth of spine was 1.5-4.0cm.No severe complication,such as screw fracture,rod fracture or nerve injury,occurred.Conclusion The pedicle screw frame system with sliding terminus had a favorable three-dimensional correction effect,and the spine growth would not be restricted,and there was no stiffness,vertebral rotation,or distortion of shaft after operation.

  1. Atlantoaxial fixation: Overview of all techniques

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    Mummaneni Praveen

    2005-01-01

    Full Text Available Over the past century, steady advances have been made in fixating an unstable atlantoaxial complex. Current options for fixation of the atlantoaxial complex include posterior clamps, posterior wiring techniques, C1-C2 transarticular screw fixation, posterior C1 lateral mass screw with C2 pars or pedicle screw fixation, and anterior transoral C1 lateral mass to C2 vertebral body fixation.

  2. Posterior transodontoid fixation: A new fixation (Kotil technique

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    Kadir Kotil

    2011-01-01

    Full Text Available Anterior odontoid screw fixation or posterior C1-2 fusion techniques are routinely used in the treatment of Type II odontoid fractures, but these techniques may be inadequate in some types of odontoid fractures. In this new technique (Kotil technique, through a posterior bilateral approach, transarticular screw fixation was performed at the non-dominant vertebral artery (VA side and posterior transodontoid fixation technique was performed at the dominant VA side. C1-2 complex fusion was aimed with unilateral transarticular fixation and odontoid fixation with posterior transodontoid screw fixation. Cervical spinal computed tomography (CT of a 40-year-old male patient involved in a motor vehicle accident revealed an anteriorly dislocated Type II oblique dens fracture, not reducible by closed traction. Before the operation, the patient was found to have a dominant right VA with Doppler ultrasound. He was operated through a posterior approach. At first, transarticular screw fixation was performed at the non-dominant (left side, and then fixation of the odontoid fracture was achieved by directing the contralateral screw (supplemental screw medially and toward the apex. Cancellous autograft was scattered for fusion without the need for structural bone graft or wiring. Postoperative cervical spinal CT of the patient revealed that stabilization was maintained with transarticular screw fixation and reduction and fixation of the odontoid process was achieved completely by posterior transodontoid screw fixation. The patient is at the sixth month of follow-up and complete fusion has developed. With this new surgical technique, C1-2 fusion is maintained with transarticular screw fixation and odontoid process is fixed by concomitant contralateral posterior transodontoid screw (supplemental screw fixation; thus, this technique both stabilizes the C1-2 complex and fixes the odontoid process and the corpus in atypical odontoid fractures, appearing as an

  3. Análise fotoelástica de parafuso de sistema de fixação vertebral The photoelastic analisys of vertebral fixation system screws

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    Sarah Fakher Fakhouri

    2009-01-01

    Full Text Available INTRODUÇÃO: A fotoelasticidade é utilizada para avaliar as tensões/deformações produzidas nos materiais fotoelásticos, quando submetidos a determinado carregamento, através da observação de efeitos óticos. O desempenho do parafuso e as funções mecânicas estão diretamente relacionados com a qualidade da fixação dos parafusos nas vértebras. A fotoelasticidade é uma ferramenta importante para realizar estudos comparativos desta natureza. OBJETIVO: O objetivo deste estudo foi comparar por meio da fotoelasticidade, as tensões internas produzidas pelo parafuso com 6 mm de diâmetro externo, quando submetido a duas diferentes forças de arrancamento. MATERIAIS E MÉTODOS: Para isso, foram confeccionados quatro modelos fotoelásticos. A simulação foi realizada utilizando duas forças de arrancamento 0,75 e 1,50 kgf. As tensões cisalhantes foram calculadas nos 19 pontos em torno dos parafusos, utilizando o método de compensação de Tardy. RESULTADOS: Os valores das tensões cisalhantes foram maiores quando utilizada a força de arrancamento de 1,50 kgf. CONCLUSÃO: Assim sendo, o parafuso estará mais suscetível ao arrancamento com a aplicação de força de maior intensidade. De acordo com as análises realizadas verificamos também que o local de maior tensão cisalhante foi observado no pico das cristas, principalmente próxima às pontas dos parafusos, independente da força utilizada.INTRODUCTION: The photoelasticity is used for assessing the tensions/deformations involved in photoelastic materials when submitted to a given load by the observation of optical effects. The screw performance and mechanical functions are directly associated to the quality of the screws fixation in the vertebrae. Photoelasticity is an important tool to perform comparative studies of this nature OBJECTIVE: The aim of this study was to compare, by using photoelasticity, internal stresses produced by the screw with an external diameter of 6 mm

  4. Biomechanical properties of monosegmental pedicle screw fixation via the fractured thoracolumbar vertebrae%经胸腰段伤椎单节段椎弓根螺钉固定后的生物力学特性

    Institute of Scientific and Technical Information of China (English)

    刘上楼; 徐军; 倪卓民; 张云庆; 周枫; 姜雪峰

    2013-01-01

    背景:临床常采用经伤椎椎弓根螺钉内固定治疗胸腰椎骨折,研究已证实经伤椎双侧椎弓根螺钉固定后脊柱稳定性加强,但也有研究认为经伤椎单节段椎弓根螺钉固定足以增加脊柱的稳定性,但此结论缺乏生物力学结果支持。  目的:观察胸腰段椎体骨折经伤椎单节段固定的相关生物力学特性。  方法:取扬州大学医学院解剖教研室提供8具中国人新鲜胸腰段标本(T11-L3),锯条横断2/3椎体,制成完整胸腰段椎体实验标本,将8具标本等分成跨伤椎固定组和单节段经伤椎固定组,分别在跨伤椎临近椎体四钉固定和临近椎体四钉固定+经伤椎单侧椎弓根固定。  结果与结论:胸腰段椎体骨折后经跨伤椎固定与经单节段伤椎固定的载荷-应变关系相差12%、载荷-位移关系相差11%、强度相差18%、轴向刚度相差11%、扭转力相差11%及拔出力相差1.8%,两组差异有显著性意义(P OBJECTIVE:To evaluate the biomechanical properties of monosegmental pedicle screws fixation via fractured vertebrae for thoracolumbar fracture. METHODS:Eight cadavers’ thoracolumbar specimens (T11-L3) were provided by the Department of Anatomy, Yangzhou University School of Medicine. Saw was used to transect 2/3 of the vertebrae in order to make complete experimental thoracolumbar specimens. Eight specimens were divided into two group;beyond-fractured vertebrae fixation group and monosegmental fixation via fracture vertebrae group. The specimens in the two groups were treated with adjacent vertebral four screw fixation beyond fractured vertebrae and adjacent vertebral four screw fixation+monosegmental pedicle screw fixation via fractured vertebrae respectively. RESULTS AND CONCLUSION:After thoracolumbar fracture, the differences between beyond fractured vertebrae fixation and monosegmental pedicle screw fixation via fractured vertebrae were as fol ows

  5. Therapeutic efficacy of pedicle screw-rod internal fixation after one-stage posterior transforaminal lesion debridement and non-structural bone grafting for tuberculosis of lumbar vertebra

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    Jia-ming LIU

    2015-11-01

    Full Text Available Objective To evaluate the efficacy and safety of pedicle screw-rod internal fixation after one-stage posterior transforaminal lesion debridement and non-structural bone grafting in the treatment of tuberculosis of mono-segmental lumbar vertebra. Methods From January 2010 to April 2013, 21 patients (9 males and 12 females with an average age of 49.1 years with mono-segmental tuberculosis of lumbar vertebra underwent surgery in our hospital were included. Eight patients had neurological deficit. The focus of tuberculosis was located on one side of the vertebral body, and all the patients had obvious signs of bone destruction on CT and MRI. All the patients were given anti-tuberculosis chemotherapy for 2-3 weeks before surgery. The local bone chips and autologous iliac cancellous bone were used as the intervertebral bone graft. Postoperative plain radiographs and CT were obtained to evaluate the fusion rate and degree of lumbar lordosis. The visual analogue scale score (VAS, erythrocyte sedimentation rate (ESR, and C-reactive protein (CRP before and after operation, and at final follow-up date were recorded. Results All the patients were followed up for 25.3±4.2 months. The mean operation time was 157±39 minutes, and the average blood loss was 470±143ml. The fusion rate of the interbody bone graft was 95.2%, with an average fusion period of 6.1±2.5 months. The neurological function was improved by 100%, and no severe complication or neurological injury occured. The preoperative and postoperative lordosis angles of the lumbar spine were 21.4°±5.7° and 33.6°±3.1°, respectively, and it was 31.3°±2.7° at the final follow up. The preoperative and postoperative VAS scores were 7.8±2.6 and 2.4±1.7 respectively, and it was 0.9±0.7 at the final follow up. The ESR and CRP were significantly decreased 3 months after surgery, and they became normal at 6 months. Conclusion Pedicle screw-rod internal fixation after one-stage posterior

  6. Treatment of acute thoracolumbar burst fractures with kyphoplasty and short pedicle screw fixation: Transpedicular intracorporeal grafting with calcium phosphate: A prospective study

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    Korovessis Panagiotis

    2007-01-01

    Full Text Available Background: In the surgical treatment of thoracolumbar fractures, the major problem after posterior correction and transpedicular instrumentation is failure to support the anterior spinal column, leading to loss of correction and instrumentation failure with associated complaints. We conducted this prospective study to evaluate the outcome of the treatment of acute thoracolumbar burst fractures by transpedicular balloon kyphoplasty, grafting with calcium phosphate cement and short pedicle screw fixation plus fusion. Materials and Methods : Twenty-three consecutive patients of thoracolumbar (T 9 to L 4 burst fracture with or without neurologic deficit with an average age of 43 years, were included in this prospective study. Twenty-one from the 23 patients had single burst fracture while the remaining two patients had a burst fracture and additionally an adjacent A1-type fracture. On admission six (26% out of 23 patients had neurological deficit (five incomplete, one complete. Bilateral transpedicular balloon kyphoplasty with liquid calcium phosphate to reduce segmental kyphosis and restore vertebral body height and short (three vertebrae pedicle screw instrumentation with posterolateral fusion was performed. Gardner kyphosis angle, anterior and posterior vertebral body height ratio and spinal canal encroachment were calculated pre- to postoperatively. Results : All 23 patients were operated within two days after admission and were followed for at least 12 months after index surgery. Operating time and blood loss averaged 45 min and 60 cc respectively. The five patients with incomplete neurological lesions improved by at least one ASIA grade, while no neurological deterioration was observed in any case. The VAS and SF-36 (Role physical and Bodily pain domains were significantly improved postoperatively. Overall sagittal alignment was improved from an average preoperative 16° to one degree kyphosis at final follow-up observation. The anterior

  7. Transpedicular vertebral body augmentation reinforced with pedicle screw fixation in fresh traumatic A2 and A3 lumbar fractures: comparison between two devices and two bone cements.

    Science.gov (United States)

    Korovessis, Panagiotis; Vardakastanis, Konstantinos; Repantis, Thomas; Vitsas, Vasilios

    2014-07-01

    This retrospective study compares efficacy and safety of balloon kyphoplasty (BK) with calcium phosphate (Group A) versus KIVA implant with PMMA (Group B) reinforced with three vertebrae pedicle screw constructs for A2 and A3 single fresh non-osteoporotic lumbar (L1-L4) fractures in 38 consecutive age- and diagnosis-matched patient populations. Extracanal leakage of both low-viscosity PMMA and calcium phosphate (CP) as well as the following roentgenographic parameters: segmental kyphosis (SKA), anterior (AVBHr) and posterior (PVBHr) vertebral body height ratio, spinal canal encroachment (SCE) clearance, and functional outcome measures: VAS and SF-36, were recorded and compared between the two groups. All patients in both groups were followed for a minimum 26 (Group A) and 25 (Group B) months. Extracanal CP and PMMA leakage was observed in four (18 %) and three (15 %) vertebrae/patients of group A and B, respectively. Hybrid fixation improved AVBHr, SKA, SCE, but PVBHr only in group B. VAS and SF-36 improved postoperatively in the patients of both groups. Short-segment construct with the novel KIVA implant restored better than BK-fractured lumbar vertebral body, but this had no impact in functional outcome. Since there was no leakage difference between PMMA and calcium phosphate and no short-term adverse related to PMMA use were observed, we advice the use of PMMA in fresh traumatic lumbar fractures. PMID:23982115

  8. Hollow screw and suture fixation for treatment of tibial intercondylar eminence fractures under arthroscopy%关节镜下空心螺钉与缝线内固定治疗胫骨髁间棘骨折

    Institute of Scientific and Technical Information of China (English)

    陈维东

    2013-01-01

    BACKGROUND:Intercondylar eminence fractures of the tibia are often treated by arthroscopic surgery, but the fixation methods are controversial. OBJECTIVE:To compare curative effect of hol ow screw and suture fixation in treatment of tibial intercondylar eminence fractures under arthroscopy. METHODS:A total of 46 patients with tibial intercondylar eminence fractures were recruited from the Third People’s Hospital of Yancheng, China from June 2010 to January 2013. According to the patient’s wil ing and physician’s suggestions, the involved patients were divided into hol ow screw group (n=25) and suture fixation group (n=21), undergoing hol ow screw and suture fixation under arthroscopy, respectively. RESULTS AND CONCLUSION:According to Ikeuchi grade, the excellent and good rate after fixation showed no significant differences between the two groups (P>0.05), but the functional training time in hol ow screw group was significantly shorter than that in suture fixation group (P  目的:比较关节镜下应用空心螺钉与缝线内固定治疗胫骨髁间棘骨折的临床疗效。  方法:收集盐城市第三人民医院自2010年6月至2013年1月收治的46例胫骨髁间棘骨折患者,根据患者意愿及医师建议分为空心螺钉组(n=25)和缝线组(n=21),分别在关节镜下行空心螺钉与缝线内固定。  结果与结论:空心螺钉组与缝线组胫骨髁间棘骨折患者固定后 Ikeuchi 膝关节评分优良率差异无显著性意义(P >0.05),但空心螺钉组患者固定后功能训练时间明显比缝线组短(P <0.05)。提示关节镜下空心螺钉治疗胫骨髁间棘骨折比缝线有利于胫骨髁间棘骨折患者的恢复。

  9. In vitro biomechanical study of pedicle screw pull-out strength based on different screw path preparation techniques

    OpenAIRE

    Mark Moldavsky; Kanaan Salloum; Brandon Bucklen; Saif Khalil; Jwalant S Mehta

    2016-01-01

    Background: Poor screw-to-bone fixation is a clinical problem that can lead to screw loosening. Under-tapping (UT) the pedicle screw has been evaluated biomechanically in the past. The objective of the study was to determine if pedicle preparation with a sequential tapping technique will alter the screw-to-bone fixation strength using a stress relaxation testing loading protocol. Materials and Methods: Three thoracolumbar calf spines were instrumented with pedicle screws that were either p...

  10. CT-guided screw fixation of vertical sacral fractures in local anaesthesia using a standard CT; CT-kontrollierte Schraubenosteosynthese von vertikalen Frakturen des hinteren Beckenringes in Lokalanaesthesie

    Energy Technology Data Exchange (ETDEWEB)

    Reuther, G.; Dehne, I. [Thueringen-Klinik, Saalfeld (Germany). Radiologische Klinik; Roehner, U.; Will, T.; Petereit, U. [Thueringen-Klinik, Saalfeld (Germany). Orthopaedics and Trauma Surgery

    2014-12-15

    To evaluate time efficiency, radiation dose, precision and complications of percutaneous iliosacral screw placement under CT-guidance in local anaesthesia. Retrospective analysis of 143 interventions in 135 patients during a period of 42 months. Implant failures could be evaluated in 85/182 screws and bony healing or refracturing in 46/182 screws. A total of 182 iliosacral screw placements in 179 vertical sacral fractures (105 unilateral, 37 bilateral) took place in 135 patients. 166/179 of the sacral fractures were detected in Denis zone 1, 10 in Denis zone 2 and 3 in Denis zone 3. No screw misplacements including the simultaneous bilateral procedures were noted. The average time for a unilateral screw placement was 23 minutes (range: 14-52 minutes) and 35 minutes (range: 21-60 minutes) for simultaneous bilateral screwing. The dose length product was 365 mGy x cm (range: 162-1014 mGy x cm) for the unilateral and 470 mGy x cm (range: 270-1271 mGy x cm) for the bilateral procedure. 1 gluteal bleeding occurred as the only acute minor complication (0.7%). Fracture healing was verified with follow-up CTs in 42/46 sacral fractures after screw placement. Backing out occurred in 12/85 screws between 6 and 69 days after intervention. In 8 patients contralateral stress fractures were detected after unilateral screw placement between day 10 and 127 (average: 48 days). CT-guided iliosacral screw placement in sacral fractures is a safe tool providing a very high precision. The radiation dose is in the order of a diagnostic CT of the pelvis for both unilateral and bilateral screws. Contralateral stress fractures in unilateral screw placements have to be considered during the first weeks after intervention.

  11. A laboratory investigation to assess the influence of cement augmentation of screw and plate fixation in a simulation of distal femoral fracture of osteoporotic and non-osteoporotic bone.

    Science.gov (United States)

    Wähnert, D; Lange, J H; Schulze, M; Gehweiler, D; Kösters, C; Raschke, M J

    2013-10-01

    The augmentation of fixation with bone cement is increasingly being used in the treatment of severe osteoporotic fractures. We investigated the influence of bone quality on the mechanics of augmentation of plate fixation in a distal femoral fracture model (AO 33 A3 type). Eight osteoporotic and eight non-osteoporotic femoral models were randomly assigned to either an augmented or a non-augmented group. Fixation was performed using a locking compression plate. In the augmented group additionally 1 ml of bone cement was injected into the screw hole before insertion of the screw. Biomechanical testing was performed in axial sinusoidal loading. Augmentation significantly reduced the cut-out distance in the osteoporotic models by about 67% (non-augmented mean 0.30 mm (sd 0.08) vs augmented 0.13 mm (sd 0.06); p = 0.017). There was no statistical reduction in this distance following augmentation in the non-osteoporotic models (non-augmented mean 0.15 mm (sd 0.02) vs augmented 0.15 mm (sd 0.07); p = 0.915). In the osteoporotic models, augmentation significantly increased stability (p = 0.017). PMID:24078541

  12. Surgical treatment of lumbar spondylolisthesis using short or long segment pedicle screw fixation%不同节段椎弓根钉置入脊椎内固定治疗腰椎滑脱

    Institute of Scientific and Technical Information of China (English)

    沈宁江; 王先安; 林庆彪; 陈建; 李一波

    2012-01-01

    BACKGROUND: There are a lot of controversies regarding the choice of short versus long segment pedicle screw fixation for the treatment of isthmic spondylolisthesis and degenerative spondylolisthesis treatment. OBJECTIVE: To investigate clinical efficacy of short versus long segment pedicle screw fixation in treatment of lumbar spondylolisthesis.METHODS: A total of 146 spondylolisthesis patients were included in this study, 36 males and 110 females, aged 22-73 years at a mean of 53 years; disease duration was from 1 to 18 years at a mean of 5 years. These patients were treated with lumbar spinal window-opened decompression or laminectomy decompression, a short or long segment pedicle screw internal fixation, transverse interbody fusion.RESULTS AND CONCLUSION: Among 146 involved patients, 72 cases were treated with four pedicle screw fixation (short segments), while 74 cases with six pedicle screw fixation (long segments). Interbody graft was performed in 101 cases, while intertransverse fusion given in 45 cases. Totally 134 cases were followed up for postoperative 1.5-14 years. According to clinical grading standards of Steffee system, the clinical efficacy was assayed excellent in 74 cases, good in 41 cases, mild in 13 cases and poor in 6 cases, with good rate of 85.8%. 77 cases achieved a complete reduction, including 32 cases using a short segment fixation and 45 cases using a long segment fixation. 69 cases achieved partial reduction, including 40 cases using a short segment fixation and 29 cases using a long segment fixation. Pedicle screws ruptures were found in 13 screws of eight patients undergoing short segment fixation, while no pedicle screw fracture was found in long segment fixation. Choice of short or long segment for the fixation is based on the analysis of spondylolisthesis type, severity, duration of disease, emergence of adjacent segment disc degeneration and instability.%背景:对椎弓峡部裂腰椎滑脱、退行性腰椎滑脱的治疗,到

  13. Possible Usage of Cannulated Pedicle Screws without Cement Augmentation

    Directory of Open Access Journals (Sweden)

    Teyfik Demir

    2014-01-01

    Full Text Available Background: The use of pedicle screws is becoming increasingly popular for spinal surgery practice as the technology advances. Screw pullout due to bone quality and loading conditions is one of the most common problems observed after pedicle screw fixation. Several solutions were studied to prevent screw pullout. These can be investigated under three main categories: screw design, expandable screws and cement augmentation.

  14. Bioabsorbable Pins for Treatment of Osteochondral Fractures of the Knee after Acute Patella Dislocation in Children and Young Adolescents

    Directory of Open Access Journals (Sweden)

    A. Gkiokas

    2012-01-01

    Full Text Available A retrospective study was performed on the use of bioabsorbable pins in the fixation of osteochondral fractures (OCFs after traumatic patellar dislocation in children. Eighteen children (13 females, 5 males aged 11 to 15 years (mean age 13.1 years with osteochondral fracture (OCF of the knee joint were treated at the authors’ institution. Followup ranged from 22 months to 5 years. Diagnosis was verified by X-ray and magnetic resonance imaging (MRI of the knee and patella. In seven patients the osteochondral fragment was detached from the patella and in 11 it was detached from the lateral femoral condyle. All patients were subjected to open reduction and fixation of the lesion with bioabsorbable pins. Postoperatively, the knee was immobilized in a cast and all patients were mobilized applying a standardized protocol. Bone consolidation was successful in 17 of the 18 patients. Bioabsorbable pins reliably fix OCF in children and adolescents, demonstrating a high incidence of consolidation of the detached osteochondral fragment in short- and middle-term followup without requiring further operative procedures.

  15. Orientation of the "Lisfranc screw".

    Science.gov (United States)

    Panchbhavi, Vinod K

    2012-11-01

    The reduction and stabilization of diastases between the medial cuneiform and the base of second metatarsal after a Lisfranc ligament injury is a crucial objective in the open reduction and internal fixation of these injuries. To achieve this objective, a single screw is used. The present practice is to insert the screw directed from the medial cuneiform bone into the base of the second metatarsal. This technique trick describes an easier method of insertion of the screw and one that possibly provides a better fixation. PMID:22549028

  16. 骨水泥强化治疗骨质疏松症伴脊柱侧弯疗效分析%Effects of pedicle screw fixation with bone cement tract augmentation on scoliolosis accompanying osteoporosis

    Institute of Scientific and Technical Information of China (English)

    丁金勇; 洪少勇; 晋大祥; 梁德; 江晓兵

    2012-01-01

    目的 探讨对伴骨质疏松症的退行性脊柱侧弯病人行后路减压、骨水泥强化钉道椎弓根内固定融合治疗的临床疗效.方法 2006-10-2009-07收治伴骨质疏松症的退变性脊柱侧弯患者18例,女11例,男7例,平均年龄64.5岁,均冠状面畸形,Cobb's角>15°或合并椎体旋转半脱位以及合并椎体骨质疏松性病理性骨折.手术采取部分椎板切除,松解神经根以充分减压,骨水泥强化钉道的椎弓根长节段钉棒系统进行矫形,记录手术前后Cobb's角、前凸角,手术前后进行ODI评分.结果 所有病例切口均Ⅰ期愈合,无感染或深静脉血栓等近期并发症;进行24~54个月随访(平均36个月),未出现断钉、断棒,及椎弓根钉拔出、松动、融合节段假关节形成或感染等远期并发症.患者术后冠状面Cobb's角均低于术前(P<0.05),腰椎矢状面前凸角均高于术前(P<0.05),ODI综合评分均低于术前(P<0.05).结论 在充分减压消除症状的基础上,用骨水泥强化钉道进行侧弯的矫形,可以获得脊柱平衡并能够避免矫形的丢失.%Objective To evaluate the clinical effect of the treatment that part or full laminecto-my and correction with posterior long segment pedicle screw/rod internal fixation system by augmentation and restoration with bone cement in the screw tract and posterolateral or intervertebral spinal fusion, about degenerative scoliolosis accompanying with osteoporosis. Methods Eighteen patients, 11 females and 7 males (average age of 643 years),with degenerative scoliosis accompanying by osteoporosis were selected from our hospital, between October 2006 and July 2009. The patients were treated with part or full laminectomy and posterior long segment pedicle screw/rod internal fixation system by augmentation and restoration with bone cement in the screw tract and posterolateral or intervertebral spinal fusion. Result All cases were followed up for 36 months (range 24-54 months). No

  17. 骨水泥强化椎弓根螺钉固定对骨质疏松患者有利无弊?★%Pedicle screw fixation augmented with bone cement benefits osteoporosis patients?

    Institute of Scientific and Technical Information of China (English)

    岳文峰; 夏虹; 王建华

    2013-01-01

    BACKGROUND:During the pedicle screw fixation for lumbar disease patients accompanied with osteoporosis, addition of bone cement in osteoporotic vertebral body can significantly increase the stability of internal fixation, but the effect on adjacent segments is not clear. OBJECTIVE:To observe the effect on adjacent segments of osteoporosis patients after pedicle screw fixation augmented with bone cement in early and medium-term fol ow-up period. METHODS:We reviewed the medical information of 87 patients suffering from lumbar disease accompanied with osteoporosis who underwent operation of pedicle screw fixation and posterior lumbar spinal decompression, and the patients were divided into three groups:conventional pedicle screw group, conventional pedicle screw+bone cement group, novel perfusional pedicle screw+bone cement group. The samples were fol owed-up for 6-18 months, averaged 9 months. The Oswestry disability index, intervertebral distance of the upper adjacent segments, deformation index of the upper adjacent vertebral body, concave angle of the fixed lumbar vertebrae superior end-plate and the upper adjacent vertebral body inferior end-plate, and Cobb angle were measured before operation, at 3 days postoperation and during final fol ow-up. RESULTS AND CONCLUSION:The Oswestry disability index of the final fol ow-up in the three groups were decreased when compared with that before operation (P0.05). This showed that in posterior spinal fixation operation, there was no significant difference in the early and medium-term subjective effect between addition of bone cement or not and different adding ways, and addition of bone cement or not and different adding ways could remarkably improve the life quality of the patients. The change of Cobb angle of fixed lumbar vertebrae between the final fol ow-up and 3 days after operation in conventional pedicle screw+bone cement group and novel perfusional pedicle screw+bone cement group was both less than that in the

  18. Cause analysis of the screw loosening after the internal fixation with thoracolumbar vertebral pedicle screw in the elderly%老年人胸腰椎椎弓根螺钉内固定术后螺钉松动原因分析

    Institute of Scientific and Technical Information of China (English)

    张思萌; 李放; 刘秀梅; 王崇伟; 王秀红

    2015-01-01

    目的 探讨老年人胸腰椎椎弓根螺钉内固定术后螺钉松动的原因及预防措施. 方法 对2011年5月至2013年5月在我院行胸腰椎椎弓根螺钉内固定手术≥60岁老年患者187例临床资料进行回顾性分析,按是否发生螺钉松动分为松动组和固定良好组,观察并比较两组患者手术时间、出血量、术后6个月及末次随访视觉模拟疼痛评分(VAS)及Oswestry功能障碍指数(ODI)评分,分析螺钉松动的原因. 结果 本组行胸腰椎椎弓根螺钉内固定手术主要病因为胸腰椎侧后凸畸形、骨折、滑脱、肿瘤及退行性疾病等,术后平均随访(35.2±8.7)个月.发生内固定松动13例(7.0%),男性5例,女性8例,平均年龄(78.4±3.5)岁.发现螺钉松动时间为术后3~12个月,平均(7.6±3.7)个月.13例患者中,螺钉松动单节段1例,双节段3例,3个或3个以上节段9例.螺钉松动患者中骨质疏松10例.VAS及ODI评分,术后6个月及末次随访与术前比较,差异均有统计学意义(P<0.05);末次随访与术后6个月比较,差异无统计学意义(P>0.05).松动组性别及术前骨质疏松患病率与固定良好组比较,差异有统计学意义(P<0.05). 结论 骨质疏松是影响老年患者胸腰椎椎弓根螺钉内固定术后螺钉松动的原因之一,长节段螺钉松动概率增高,可能与老年患者脊柱力学改变有关.对于老年骨质疏松患者,是否需要骨水泥强化治疗,仍需进一步随机对照研究.%Objective To explore what cause the screw loosening after the internal fixation with thoracic and lumbar pedicle screws in the elderly and to develop the preventive measures.Methods Retrospective analysis were used to collect the clinical data from patients ager 60 years and over who had undergone surgeries of thoracolumbar pedicle screw internal fixation in our hospital during May 2011 and May 2013.Totally 187 cases were included in this study.According to whether there was a loosening of

  19. Percutaneous fixation with Schanz screws for displaced two- and three- part fractures of the proximal humerus in patients above fifty years of age

    OpenAIRE

    Abdelsalam Eid; Mohamed Osman; Hosam-Eldeen Fekry

    2011-01-01

    Purpose: The aim of this study is to evaluate whether two 3.0 mm Schanz screws in two-part proximal humeral fractures (plus one additional Schanz screw or K wire in three-part fractures) can provide enough stability to allow early mobilization until healing occurs in elderly patients. Settings and Design: This prospective study was performed in the Orthopaedic Department of our University Hospital. Patients and Methods: We performed closed reduction and percutaneous pinning for thirt...

  20. A Biomechanical Comparison of Expansive Pedicle Screws for Severe Osteoporosis: The Effects of Screw Design and Cement Augmentation.

    Science.gov (United States)

    Tai, Ching-Lung; Tsai, Tsung-Ting; Lai, Po-Liang; Chen, Yi-Lu; Liu, Mu-Yi; Chen, Lih-Huei

    2015-01-01

    Expansive pedicle screws significantly improve fixation strength in osteoporotic spines. However, the previous literature does not adequately address the effects of the number of lengthwise slits and the extent of screw expansion on the strength of the bone/screw interface when expansive screws are used with or without cement augmentation. Herein, four designs for expansive pedicle screws with different numbers of lengthwise slits and different screw expansion levels were evaluated. Synthetic bones simulating severe osteoporosis were used to provide a comparative platform for each screw design. The prepared specimens were then tested for axial pullout failure. Regardless of screw design, screws with cement augmentation demonstrated significantly higher pullout strength than pedicle screws without cement augmentation (p screws without cement augmentation, solid screws exhibited the lowest pullout strength compared to the four expansive groups (p screws with different designs (p > 0.05). Taken together, our results show that pedicle screws combined with cement augmentation may greatly increase screw fixation regardless of screws with or without expansion. An increase in both the number of slits and the extent of screw expansion had little impact on the screw-anchoring strength. Cement augmentation is the most influential factor for improving screw pullout strength. PMID:26720724

  1. 椎弓根螺钉内固定及计算机导航技术的发展与应用%Development and application of pedicle screw fixation and computer navigation technology

    Institute of Scientific and Technical Information of China (English)

    靳冬; 张果忠

    2012-01-01

    BACKGROUND: Thoracolumbar pedicle screw fixation techniques play an important role in the development of spinal surgery, and spine computer navigation system can significantly improve the accuracy and safety of pedicle screws. OBJECTIVE: To study the clinical application of pedicle screw fixation. MESHODS: A computer-based retrieve was performed for the articles on the application of pedicle screw fixation and computer navigation technology in the fixation from January 1999 to December 2011 with the key words of "pedicle screw fixation, computer navigation technology, clinical application" in Chinese. Repetitive articles and Meta analysis articles were eliminated. Finally, 25 articles were included to discuss the research progress of pedicle screw fixation and relevant evaluation. RESULTS AND CONCLUSION: Computer-aided surgical technique is a new technology that can help surgeons to make the surgery safer and accurately through virtual the surgical environment based on the high-speed processing of large amounts of data information and control capabilities of computer. Recently, we have achieved great development on the study of thoracolumbar pedicle screws technology, especially the intraoperative monitoring tool, it has developed from traditional X-ray fluoroscopy or radiography monitoring and positioning to visualize monitoring by computer-aided technology. Computer navigation technology can simulate and measure the length and angle of the pin tract and the diameter of pedicle from the three-dimensional image data stored in the computer, which is benefit to select the pedicle screw with the best length and diameter, so that to make the pedicle screw surgery more precise, simple, fast and safe and then reduce the occurrence of postoperative complications.%背景:胸腰椎椎弓根螺钉内固定技术的开展,有力地推动了脊柱外科的发展,而脊柱计算机导航系统可以明显改进椎弓根螺钉植入的精确性和安全性.目的:研究近年

  2. MRI of menisci repaired with bioabsorbable arrows

    Energy Technology Data Exchange (ETDEWEB)

    Mustonen, Antti O.T.; Kiuru, Martti; Koskinen, Seppo K. [Helsinki University Hospital - Radiology, Helsinki (Finland); Tielinen, Laura; Lindahl, Jan; Hirvensalo, Eero [Helsinki University Hospital - Traumatology, Helsinki (Finland)

    2006-07-15

    To analyze with conventional magnetic resonance imaging (MRI) the signal appearance of menisci repaired with bioabsorbable arrows. Forty-four patients with 47 meniscal tears treated with bioabsorbable arrows underwent follow-up conventional MRI examination. The time interval between the surgery and MRI varied from 5 to 67 months (mean 26 months). Twenty-six patients also had concurrent repair of torn anterior cruciate ligament. The following grades were used to classify meniscal signal intensity: (a) G0; low signal intensity on all sequences and regular configuration in every plane, (b) G1; increased signal intensity within the meniscus, not extending to the meniscal surface, (c) G2; increased signal intensity linear in shape, which may or may not communicate with the capsular margin of the meniscus, without extending to the meniscal surface, and (d) G3; increased signal intensity extending to the meniscal surface. Thirteen menisci (27.5%) had normal signal intensity, 13 menisci (27.5%) Grade 1 signal intensity, 9 menisci (19%) Grade 2 signal intensity and 12 menisci (26%) Grade 3 signal intensity. The time difference between operation and MRI was statistically significant between the G0 (36 months) and G3 groups (14 months; P=0.0288). There was no statistical significance in different grades between medial and lateral meniscus or between patients with operated or intact ACL. On physical examination sixteen patients reported slight symptoms, seen evenly in each group. (orig.)

  3. MRI of menisci repaired with bioabsorbable arrows

    International Nuclear Information System (INIS)

    To analyze with conventional magnetic resonance imaging (MRI) the signal appearance of menisci repaired with bioabsorbable arrows. Forty-four patients with 47 meniscal tears treated with bioabsorbable arrows underwent follow-up conventional MRI examination. The time interval between the surgery and MRI varied from 5 to 67 months (mean 26 months). Twenty-six patients also had concurrent repair of torn anterior cruciate ligament. The following grades were used to classify meniscal signal intensity: (a) G0; low signal intensity on all sequences and regular configuration in every plane, (b) G1; increased signal intensity within the meniscus, not extending to the meniscal surface, (c) G2; increased signal intensity linear in shape, which may or may not communicate with the capsular margin of the meniscus, without extending to the meniscal surface, and (d) G3; increased signal intensity extending to the meniscal surface. Thirteen menisci (27.5%) had normal signal intensity, 13 menisci (27.5%) Grade 1 signal intensity, 9 menisci (19%) Grade 2 signal intensity and 12 menisci (26%) Grade 3 signal intensity. The time difference between operation and MRI was statistically significant between the G0 (36 months) and G3 groups (14 months; P=0.0288). There was no statistical significance in different grades between medial and lateral meniscus or between patients with operated or intact ACL. On physical examination sixteen patients reported slight symptoms, seen evenly in each group. (orig.)

  4. Biomechanical characteristics of calcium phosphate cement in the reinforcement of vertebral pedicle screw fixation%磷酸钙骨水泥强化椎弓根螺钉固定的生物力学特性

    Institute of Scientific and Technical Information of China (English)

    黎逢峰; 张庆宏; 黄野; 王云华

    2006-01-01

    组椎骨,用磷酸钙骨水泥重新固定12 h后拔松的椎弓根螺钉,测定其两侧的最大轴向拔出力.主要观察指标:①磷酸钙骨水泥最终凝固时强化椎弓根螺钉固定的生物力学测试结果.②磷酸钙骨水泥初步凝固时强化椎弓根螺钉固定的生物力学测试结果.③磷酸钙骨水泥强化松动椎弓根螺钉固定的生物力学测试结果.结果:①50岁组对照侧和强化侧的椎弓根螺钉最大轴向拔出力中位数分别为620 N和1 136 N,强化侧较对照侧增加83%(P<0.01).强化骨-螺钉界面的抗剪切应力中位数从1.16 N/mm2增加到2.13 N/mm2.②52岁组对照侧和强化侧的椎弓根螺钉最大轴向拔出力中位数分别为554.5 N和859.5 N,强化侧较对照侧增加55%(P<0.01).强化骨-螺钉界面的抗剪切应力中位数从1.039 N/mm2增加到1.61 N/mm2.③50岁组椎骨对照侧和强化侧重新固定12 h后最大轴向拔出力中位数分别为517 N和876 N,和同侧松动后轴向拔出力中位数比较,分别增加了63.6%和54.2%(P均<0.01).结论:磷酸钙骨水泥初步凝固和最终凝固时能强化椎弓根螺钉的固定,并且椎弓根螺钉松动后使用磷酸骨水泥能使螺钉重新获得固定.椎体强化侧的椎弓根螺钉均从骨-螺界面剥离开来,不伴周边骨质和椎弓根的严重损害,有利于螺钉松动、拔出后的二次置入.%BACKGROUND: Polymethylmethacrylate (PMMA) can ameliorate the condition between vertebral pedicle screws and peripheral bone-matrix interfaces and notably enhance the strength of screw fixation. However, there are several disadvantages during and after operation such as polymerized thermal damaging effect, toxicity and unabsorbable etc. Calcium phosphate cement (CPC) is biocompatible and biodegradable with good biosafty and produce no heat of polymerization, which is a perfect substitute for PMMA.OBJECTIVE: To evaluate the reinforcing effect of CPC on vertebral pedicle screw fixation at

  5. "徒手法"个体化颈椎椎弓根螺钉技术治疗上颈椎骨折脱位%Free-hand cervical pedicle screw fixation for upper cervical fracture and instability

    Institute of Scientific and Technical Information of China (English)

    韩岳; 夏群; 徐宝山; 张继东; 苗军

    2011-01-01

    目的 探讨应用颈椎椎弓根钉治疗上颈椎骨折及脱位的临床效果.方法 2006年9月-2009年1月,应用颈椎椎弓根钉治疗的上颈椎骨折或脱位的患者15例.其中男11例,女4例;年龄18~60岁,平均41.2岁.寰椎骨折脱位5例,枢椎骨折脱位3例,齿状突陈旧骨折不愈合1例,C2,3骨折脱位2例,无骨折寰枢椎失稳4例.临床主要症状为颈部疼痛或伴有四肢麻木无力、步态不稳.患者术前均行Halo架牵引试行复位.所有患者均采用颈椎椎弓根钉固定并植骨融合,根据术前X线片及CT个体化确定入钉点及置钉角度,徒手法钻出骨性通道,选用22~26 mm长的Vertex或Summit钛金属螺钉固定,并行后路椎板间自体或同种异体骨植骨融合.术后1~2 d佩戴颈托离床活动.结果 本组15例共置入颈椎椎弓根螺钉64枚,均未发生椎动脉和脊髓损伤,无脑脊液漏.术后行X线正、侧位片和CT检查证实损伤节段复位满意、螺钉位置良好.术后疼痛症状基本消失,神经症状较术前有不同程度的改善.14例患者获得随访,时间12~36个月,患者颈椎序列良好,均获得骨性融合,未发生螺钉及钛棒的松动、脱出及折断.神经损伤症状较术前明显改善.结论 颈椎椎弓根钉是颈椎后路手术中坚强的固定方法,只要掌握手术操作技巧,严格个体化置钉,颈椎椎弓根钉具有固定可靠、术后并发症少、融合率高等优势,具有良好的临床疗效.%Objective To evaluate the clinical effect of the free-hand cervical pedicle screw fixation in treatment of the upper cervical fracture and instability.Methods A retrospective review was performed on 15 patients with upper cervical fracture and instability treated with cervical pedicle screw fixation and fusion from September 2006 to January 2009.There were 11 males and 4 females,at average age of 41.2 years(range,18-60 years).Of all,there were five patients with atlas fracture and dislocation

  6. Surgical treatment of the osteoporotic spine with bone cement-injectable cannulated pedicle screw fixation: technical description and preliminary application in 43 patients

    Directory of Open Access Journals (Sweden)

    Fei Dai

    2015-02-01

    Full Text Available OBJECTIVES: To describe a new approach for the application of polymethylmethacrylate augmentation of bone cement-injectable cannulated pedicle screws. METHODS: Between June 2010 and February 2013, 43 patients with degenerative spinal disease and osteoporosis (T-score <-2.5 underwent lumbar fusion using cement-injectable cannulated pedicle screws. Clinical outcomes were evaluated using a Visual Analog Scale and the Oswestry Disability Index. Patients were given radiographic follow-up examinations after 3, 6, and 12 months and once per year thereafter. RESULTS: All patients were followed for a mean of 15.7±5.6 months (range, 6 to 35 months. The Visual Analog Scale and Oswestry Disability Index scores showed a significant reduction in back pain (p = 0.018 and an improvement in lower extremity function (p = 0.025 in patients who underwent lumbar fusion using the novel screw. Intraoperative cement leakage occurred in four patients, but no neurological complications were observed. Radiological observation indicated no loosening or pulling out of the novel screw, and bone fusion was excellent. CONCLUSIONS: The described polymethylmethacrylate augmentation technique using bone cement-injectable cannulated pedicle screws can reduce pain and improve spinal dysfunction in osteoporotic patients undergoing osteoporotic spine surgery.

  7. 单螺钉内固定法在髁突矢状骨折治疗中的应用%Clinical comparsion of single screw-fixation treatment and conservative treatment in sagittal fracture of the madibular condyle

    Institute of Scientific and Technical Information of China (English)

    李健; 张智星; 柳江太; 邓末宏; 龙星

    2014-01-01

    目的:探讨单螺钉内固定治疗下颌骨髁突矢状骨折的临床效果和应用价值。方法:对27例髁突矢状骨折病例进行回顾研究,根据治疗方式分为单螺钉内固定组和保守治疗组,比较术后3个月两组患者术后并发症、咬合关系、最大开口度、颞下颌关节功能障碍指数(DI)和肌肉压痛指数(PI)等情况,进行统计学分析。结果:单螺钉内固定组术后未出现关节区疼痛、张口受限和关节强直等严重并发症,DI和PI各指标均优于保守治疗组,两组的差异具有显著统计学意义。结论:单螺钉内固定手术方法是一种行之有效的髁突矢状骨折治疗手段,疗效确切。%Objective:To compare the effects of single screw-fixation treatment and conservative treatment in sagittal fracture of the madibular condyle(SFMC). Method:Patients with SFMC were single-screw fixation(SSF) group and the con-servative treatment (CON) group. Index,such as occlusion, maximum opening,and function of temporomandibular joint, were recorded and analyzed. Result:All patients in the SSF group had favorable results,including good occlusion,satisfying function and without serious complications or ankylosis,etc. Conclusion:Single screw-fixation surgery is an effective treat-ment used in sagittal fracture of the mandibular condyle.

  8. 重度骨质疏松条件下椎弓根螺钉内固定的可靠性研究%The Reliability of Pedicle Screw Fixation in the Spine Surgery with Severe Osteoporosis

    Institute of Scientific and Technical Information of China (English)

    李旭升; 高明暄; 赵锟; 邵宏斌; 李生贵; 陈彦飞; 常彦峰

    2015-01-01

    目的:评价重度骨质疏松条件下椎弓根螺钉的稳定性,为椎弓根内固定在合并有重度骨质疏松症的患者中的选用提供力学理论基础。方法采用新鲜尸体脊柱标本,检测骨密度后,根据诊断标准,选用正常骨质的2具尸体标本、重度骨质疏松的4具尸体标本,分离T12~L5节段成单个椎体以备后用;然后在骨质正常椎体置入椎弓根螺钉12枚作对照组;在重度骨质疏松水平,分单纯置入椎弓根螺钉( pedicle screw,PS)、经磷酸钙骨水泥( calcium phos-phate cement,CPC)强化钉道后置入椎弓根螺钉、经聚甲基丙烯酸甲酯( polymethylmethacrylate,PMMA)强化钉道后置入椎弓根螺钉三种方法置钉,依次为PS组、CPC/PS组和PMMA/PS组,进行螺钉轴向拔出实验,测最大拔出力、刚度和能量吸收值,对所测指标进行组间对比分析。结果重度疏松条件下,PS组、CPC/PS组和PMMA/PS各组最大拔出力、刚度、能量吸收值均显著低于对照组( P0.05)。结论重度骨质疏松条件下,椎弓根螺钉固定强度明显下降,不宜单纯应用普通椎弓根螺钉行脊柱内固定治疗,采用普通骨水泥强化钉道后置钉可以提高椎弓根螺钉稳定性。%Objective To evaluate the fixation of pedicle screw in the lumbar spine with severe osteoporosis,further to provide theoretical evidence for clinical application of pedicle screw in patient with severe osteoporosis. Methods Fresh hu-man cadaver spines were used. Two of them were normal and four were severe osteoporosis,according to the value of bone min-eral density. The vertebra was bilaterally instrumented pedicle screws,resulting in 24 screws in normal BMD group,as the con-trol group. The vertebrae at severe osteoporosis level was bilaterally instrumented with pedicle screws according to three proto-cols,including pedicle screw without augmentation,pedicle screw with calcium phosphate cement

  9. Bone cement and bone grafting in nail path to strengthen dynamic hip screw fixation for senile osteoporotic intertrochanteric fracture%骨水泥、钉道植骨强化动力髋螺钉固定修复老年骨质疏松性股骨转子间骨折

    Institute of Scientific and Technical Information of China (English)

    林周胜; 孙鸿涛; 夏雄智; 江成; 黎飞猛

    2015-01-01

    背景:对于老年骨质疏松性髋部骨折的动力髋螺钉固定,如能避免使用过程中造成的骨量丢失,或是采用其他手段增加固定螺钉把持力,将改善动力髋螺钉固定的治疗效果。目的:对比研究3种固定方式修复老年骨质疏松性股骨转子间骨折的效果。方法:回顾性分析近5年来采用常规动力髋螺钉内固定、骨水泥强化后动力髋螺钉固定及主钉道压配植骨配合动力髋螺钉固定3种固定方式治疗老年骨质疏松性股骨转子间骨折患者的资料,分别设为对照组、骨水泥组和植骨组。结果与结论:经固定后2年随访,植骨组、骨水泥组和对照组Harris髋关节功能评分优良率分别为95%,80%,70%。植骨组骨折临床愈合时间明显缩短(P <0.05),出现螺钉固定失败情况与骨水泥组相当。对照组较其他2组相对更多出现退钉等内固定失败情况。结果表明,与其他常规动力髋螺钉内固定、骨水泥强化后动力髋螺钉固定方式相比较,主钉道压配植骨配合动力髋螺钉内固定的疗效及安全性更好。%BACKGROUND:In dynamic hip screw fixation for treating aged osteoporotic intertrochanteric fracture, avoiding the loss of bone mass, or by other means that can increase the fixed screw pulout strength, wil improve the therapeutic effect of dynamic hip screw fixation. OBJECTIVE: To compare the effects of three kinds of repair methods on aged osteoporotic intertrochanteric fracture. METHODS:Data of aged osteoporosis intertrochanteric fracture patients, who received conventional dynamic hip screw fixation, bone cement augmentation with dynamic hip screw fixation and bone grafting with dynamic hip screw fixation, were retrospectively analyzed. They were divided into control group, bone cement group and bone grafting group. RESULTS AND CONCLUSION:After two years of folow-up, the excelent and good rates of Harris hip function were 95%, 80% and 70% in

  10. The clinical effects of osteoporosis of lumbar degenerative disease by injectable calcium sulfate bone cement to strengthen pedicle screw internal fixation%骨质疏松腰椎退行性疾病的手术治疗分析

    Institute of Scientific and Technical Information of China (English)

    孔祥瑞; 刘德政; 刘海峰; 杨计策; 赵志超

    2015-01-01

    ObjectiveTo explore the clinical effects of osteoporosis of lumbar degenerative disease by injectable calcium sulfate bone cement to strengthen pedicle screw internal fixation. Methods 82 cases of patients with lumbar degenerative dis-ease of osteoporosis word randomly divided into experiment group(41 cases) and control group(41 cases). The control group were treated by transpedicle screws fixation, the experiment group were treated by injectable calcium sulfate bone cement to strengthen pedicle screw internal fixation. The time of operation, mean bleeding volum, the scores of VAS, ODI, JOA were com-pared for the two groups. ResultsThe time of operation, mean bleeding volum for the experiment group were better than the control group; There was no significant difference on the scores of VAS, ODI, JOA; The scores of VAS, ODI for the experiment group were lower than the control group postoperation for 1 week, 2 months, 12 months; The scores of JOA for the experiment group were higher than the control group postoperation for 1 week, 2 months, 12 months. ConclusionIt can improve the scores of VAS, ODI, JOA for the patients with osteoporosis of lumbar degenerative disease by injectable calcium sulfate bone cement to strengthen pedicle screw internal fixation. It is worthy of clinical promotion.%目的:探讨可注射硫酸钙骨水泥强化椎弓根钉内固定治疗骨质疏松腰椎退行性疾病的临床疗效。方法:按照随机数字表法将我院收治的82例骨质疏松腰椎退行性疾病患者均分为实验组和对照组,对照组给予单纯椎弓根内固定治疗,实验组给予可注射硫酸钙骨水泥强化椎弓根钉内固定治疗。比较两组患者手术时间、术中出血量以及治疗前后疼痛视觉模拟评分(VAS)、Oswestry 功能障碍指数(ODI)、JOA 腰椎病疗效评分变化情况。结果:实验组患者手术时间和术中出血量显著高于对照组;两组患者术前 VAS 评分、ODI 评分、JOA

  11. Geometric accuracy of 3D coordinates of the Leksell stereotactic skull frame in 1.5 Tesla- and 3.0 Tesla-magnetic resonance imaging. A comparison of three different fixation screw materials

    International Nuclear Information System (INIS)

    We assessed the geometric distortion of 1.5-Tesla (T) and 3.0-T magnetic resonance (MR) images with the Leksell skull frame system using three types of cranial quick fixation screws (QFSs) of different materials—aluminum, aluminum with tungsten tip, and titanium—for skull frame fixation. Two kinds of acrylic phantoms were placed on a Leksell skull frame using the three types of screws, and were scanned with computed tomography (CT), 1.5-T MR imaging and 3.0-T MR imaging. The 3D coordinates for both strengths of MR imaging were compared with those for CT. The deviations of the measured coordinates at selected points (x = 50, 100 and 150; y = 50, 100 and 150) were indicated on different axial planes (z = 50, 75, 100, 125 and 150). The errors of coordinates with QFSs of aluminum, tungsten-tipped aluminum, and titanium were <1.0, 1.0 and 2.0 mm in the entire treatable area, respectively, with 1.5 T. In the 3.0-T field, the errors with aluminum QFSs were <1.0 mm only around the center, while the errors with tungsten-tipped aluminum and titanium were >2.0 mm in most positions. The geometric accuracy of the Leksell skull frame system with 1.5-T MR imaging was high and valid for clinical use. However, the geometric errors with 3.0-T MR imaging were larger than those of 1.5-T MR imaging and were acceptable only with aluminum QFSs, and then only around the central region. (author)

  12. 经皮空心钉固定治疗创伤性耻骨联合分离%Percutaneous cannulate screw fixation in treating the traumatic diastasis of the pubic symphysis

    Institute of Scientific and Technical Information of China (English)

    石成弟; 郭晓山; 胡炜; 余可和

    2011-01-01

    目的 探讨经皮空心钉固定治疗创伤性耻骨联合分离的手术方法及临床疗效.方法 2003年2月至2010年12月,治疗46例伴耻骨联合分离的不稳定骨盆骨折,男27例,女19例;年龄18~61岁,平均34.6岁.按Tile分型:B1.1型4例,B1.2型7例,B2型2例,B3型2例,C1.1型7例,C1.2型7例,C1.3型10例,C2型5例,C3型2例.行闭合复位经皮耻骨联合螺钉内固定后,再行后环固定,包括经皮骶髂螺钉、经皮髂骨后部螺钉固定.除4例B1.1型骨折仅固定耻骨联合外,余均同时行后环固定.结果 手术时间15~65 min,平均45 min;出血量10~50 ml,平均25 ml.46例患者均置入1枚耻骨联合螺钉,35例术后行骨盆CT检查,其中3例发现螺钉侵入盆腔,但未引起任何临床症状.术后无一例发生切口及钉道感染.46例患者均获得随访,随访时间5~48个月,平均23.5个月;随访期间未发现明显的复位丢失.根据Matta和Tornetta标准,末次随访时优43例,良3例.31例(67.39%)患者恢复原工作,6例因合并损伤而改变原工作,9例尚处于恢复期.28例患者无骶髂关节疼痛;13例仅在用力时有耻骨联合部或耻骨微痛,但不影响日常生活;5例有不同程度的骶髂关节疼痛.结论 闭合复位经皮空心钉固定治疗创伤性耻骨联合分离安全可行,操作简便,损伤小,疗效满意.%Objective To study the technique and therapeutic effect of percutaneous cannulate screw fixation to treat the traumatic diastasis of the pubic symphysis.Methods From February 2003 to December 2010,46 patients (27 men and 19 women,mean age of 34.6 years) with unstable pelvic fractures and diastasis of the pubic symphysis were admitted.All the patients were treated by closed reduction and percutaneous cannulate screw fixation of the symphysis pubis.Then to complete the fixation of posterior ring,by percutaneous screw inserted through the sacroiliac joint or posterior iliac wing.According to Tile's classification,the patients

  13. Less invasive reduction and fusion of fresh A2 and A 3 traumatic L 1-L 4 fractures with a novel vertebral body augmentation implant and short pedicle screw fixation and fusion.

    Science.gov (United States)

    Korovessis, Panagiotis; Vardakastanis, Konstantinos; Repantis, Thomas; Vitsas, Vasilios

    2014-04-01

    The aim of this clinical study was to report on the efficacy in reduction and safety in PMMA leakage of a novel vertebral augmentation technique with PEEK and PMMA, together with pedicle screws in the treatment of fresh vertebral fractures in young adults. Twenty consecutive young adults aged 45 ± 11 years with fresh burst A3/AO or severely compressed A2/AO fractures underwent via a less invasive posterior approach one-staged reduction with a novel augmentation implant and PMMA plus 3-vertebrae pedicle screw fixation and fusion. Radiologic parameters as segmental kyphosis (SKA), anterior (AVBHr) and posterior vertebral body height ratio (PVBHr), spinal canal encroachment (SCE), cement leakage and functional parameters as VAS, SF-36 were measured pre- and post-operatively. Hybrid construct restored AVBHr (P < 0.000), PVBHr (P = 0.02), SKA (P = 0.015), SCE (P = 0.002) without loss of correction at an average follow-up of 17 months. PMMA leakage occurred in 3 patients (3 vertebrae) either anteriorly to the fractured vertebral body or to the adjacent disc, but in no case to the spinal canal. Two pedicle screws were malpositioned (one medially, one laterally to the pedicle at the fracture level) without neurologic sequelae. Solid posterolateral spinal fusion occurred 8-10 months post-operatively. Pre-operative VAS and SF-36 scores improved post-operatively significantly. This study showed that this novel vertebral augmentation technique using PEEK implant and PMMA reduces and stabilizes via less invasive technique A2 and A3 vertebral fractures without loss of correction and leakage to the spinal canal. PMID:24170266

  14. Complicaciones de los tornillos de bloqueo intermaxilar en el tratamiento de las fracturas mandibulares Complications of self-tapping bone screws for maxillomandibular fixation in the treatment of jaw fracture

    Directory of Open Access Journals (Sweden)

    J. Molina Montes

    2008-08-01

    Full Text Available Durante la última década se ha introducido el tornillo de bloqueo intermaxilar como método de fijación maxilomandibular en el tratamiento de las fracturas de mandíbula. El propósito del estudio es evaluar las complicaciones de la técnica y la yatrogenia dental que derivan de su aplicación durante un periodo de 4 años. Se han revisado un total de 62 pacientes y 272 tornillos y, aunque han aparecido complicaciones, su incidencia es baja.In the last decade, self-tapping bone screws have been used widely as a temporary maxillomandibular fixation method in the treatment of jaw fractures. The purpose of the present study was to evaluate the complications of the technique and potential dental iatrogenesis over a period of 4 years. We reviewed a total of 62 patients and 272 screws. Although complications appeared, the complication rate was low.

  15. Morphometric evaluation of subaxial cervical spine using multi-detector computerized tomography (MD-CT) scan: the consideration for cervical pedicle screws fixation

    OpenAIRE

    Chanplakorn, Pongsthorn; Kraiwattanapong, Chaiwat; Aroonjarattham, Kitti; Leelapattana, Pittavat; Keorochana, Gun; Jaovisidha, Suphaneewan; Wajanavisit, Wiwat

    2014-01-01

    Background Cervical pedicle screw (CPS) insertion is a technically demanding procedure. The quantitative understanding of cervical pedicle morphology, especially the narrowest part of cervical pedicle or isthmus, would minimize the risk of catastrophic damage to surrounding neurovascular structures and improve surgical outcome. The aim of this study was to investigate morphology and quantify cortical thickness of the cervical isthmus by using Multi-detector Computerized Tomography (MD-CT) sca...

  16. A Biomechanical Comparison of Expansive Pedicle Screws for Severe Osteoporosis: The Effects of Screw Design and Cement Augmentation.

    Directory of Open Access Journals (Sweden)

    Ching-Lung Tai

    Full Text Available Expansive pedicle screws significantly improve fixation strength in osteoporotic spines. However, the previous literature does not adequately address the effects of the number of lengthwise slits and the extent of screw expansion on the strength of the bone/screw interface when expansive screws are used with or without cement augmentation. Herein, four designs for expansive pedicle screws with different numbers of lengthwise slits and different screw expansion levels were evaluated. Synthetic bones simulating severe osteoporosis were used to provide a comparative platform for each screw design. The prepared specimens were then tested for axial pullout failure. Regardless of screw design, screws with cement augmentation demonstrated significantly higher pullout strength than pedicle screws without cement augmentation (p 0.05. Taken together, our results show that pedicle screws combined with cement augmentation may greatly increase screw fixation regardless of screws with or without expansion. An increase in both the number of slits and the extent of screw expansion had little impact on the screw-anchoring strength. Cement augmentation is the most influential factor for improving screw pullout strength.

  17. 经皮椎弓根内固定治疗胸腰椎骨折的效果及并发症分析%Therapeutic effects and complications of percutaneous pedicle screw fixation for thoracolumbar fractures

    Institute of Scientific and Technical Information of China (English)

    罗鹏; 徐良丰; 倪文飞; 王向阳; 林焱; 毛方敏; 黄其杉; 徐华梓; 池永龙

    2011-01-01

    Objective To investigate the therapeutic effects and complications of percutaneous pedicle screw fixation for thoracolumbar fractures. Methods From January 2002 to December 2008,103 patients with thoracolumbar fractures were treated with percutaneous pedicle screw fixation, including 75 males and 28 females, the average age was 45.6 years ( range, 18-72 years). All of them were of no neurological deficits. There were 65 cases of traffic injury, 23 cases of fall injury and 15 cases of smashed injury. According to the Denis classification, 64 patients were of compression fractures, and 39 patients of burst fractures. There were 5 cases had fractures in T11, 30 in T12, 42 in L1, 15 in L2, 4 in L3, 3 in L4 ,2 in T11-12, 1 in L1-2, and 1 in L2-3. Radiological examinations, including X-ray and CT examinations, and clinical examinations were carried out to evaluate the therapeutic effects. Results Twenty one patients were lost to follow up, the remaining were followed up from 10 to 48 months with an average of 27.4 months.Before the operation, the vertebral height, the kyphposis angle and the occupation of spinal canal were (54. 5 ±8. 7)%, 16. 4°±2. 9°and 1.2 ± 1. 0, and were improved to (88.6 ±6. 4)%, 11.6°± 2. 7°and 0. 5 ± 0. 6 respectively after the operation. Preoperatively the visual analogue scale and the Oswestry disability index were 8. 0 ± 1.2 and 41.2 ± 9. 3, and were improved to 1.7 ± 1.8 and 6. 7 ± 5.6 postoperatively,respectively. All of these values between pre- and post-operatively were significantly different (P <0. 01 ). Screw misplacement was found in 7 patients, superficial wound infection in 1, screw breakage in 3, screw dislodgment in 2, cement leakage in 5, transient neurological symptoms in 4, and 8 patients with low back pain remained,of which 2 patients required occasional oral analgesics. Bone fusion achieved in all cases. Conclusions The clinical efficacy of percutaneous pedicle screw fixation is similar with conventional open

  18. The clinical efficacy of degenerative scoliosis treatment via posterior pedicle screw fixation%后路椎弓根钉棒固定治疗退变性脊柱侧弯的临床疗效

    Institute of Scientific and Technical Information of China (English)

    关永林; 赵学权; 王振东; 马斌祥; 孙乐伟

    2016-01-01

    Objective To explore the clinical effects of posterior pedicle screw fixation technique in the treatment of degenerative scoliosis .Methods The corrective surgery effects of 20 patients with degenerative scoliosis were ob-served.For 1 patient whose Cobb angle 20°,the surgery of spinal decom-pression, spinal fusion, long pedicle screw system fixation and bone grafting were carried out .Results All patients were followed up for 6 months, and there were not patients with postoperative infection , broken screws or broken rods and so on.All the patients′angle of thoracic lumbar segment′s kyphosis and lumbar lordosis and Cobb angle meas-ured after surgery had shown significant improvement compared with the preoperative (P<0.05),the lumbar lordosis and Cobb angle measured at 6 months after surgery had shown significant improvement compared with the postopera -tive(P<0.05); JOA score and ODI had both been significantly improved compared with the preoperative (P<0.05),the JOA score and ODI measured at 6 months after surgery had both been significantly improved compared with the postoperative(P<0.05).Conclusions On the basis of spinal decompression , which is the premise of re-ducing the pain, carrying out the surgery of posterior pedicle screw system fixation can reconstruct spine′s stability, and improve patients′life quality.%目的:探讨后路椎弓根螺钉固定技术治疗退变性脊柱侧弯的临床效果。方法对20例退变性脊柱侧弯患者进行手术矫正,对Cobb角<20°的1例患者行椎管减压、椎体融合、短节段椎弓根钉棒系统固定术;对Cobb角>20°的19例患者行椎管减压、椎体融合、长节段椎弓根钉棒系统固定并植骨融合术。结果患者均获得6个月的随访。未出现术后感染及断钉、断棒等情况。 Cobb角、腰椎前凸角和胸腰段后凸角:术后均较术前明显改善( P<0.05),术后6个月均较术后进一步改善( P<0.05)。 JOA评分及ODI评

  19. 椎弓根内固定椎体后凸成形术治疗骨质疏松性胸腰椎骨折%Pedicle Screw Fixation Kyphoplasty in Treatment of Osteoporotic Thoracolumbar Fracture

    Institute of Scientific and Technical Information of China (English)

    柯勇

    2013-01-01

    目的探讨椎弓根内固定结合椎体后凸成形术治疗骨质疏松性胸腰椎骨折的方法及临床治疗的效果。方法自2011年2月~2012年2月本院采用后路切开椎弓根内固定结合椎体后凸成形术治疗13例骨质疏松性胸腰椎压缩性骨折患者。术后随访24个月,术后复查胸腰椎正侧位片。分别于术前、术后4d、末次随访用Oswestry功能障碍指数评分(oswestry disability index,ODI),X线片上测量椎体矢状面指数(sagittal index,SI)及Cobb角(SI=椎体前缘高度/椎体后缘高度),观察内固定及伤椎稳定及功能恢复情况。结果所有患者都未发生骨水泥渗漏,无神经症状的缺失。13例患者中,12例获平均20个月随访,末次随访时患者的功能恢复良好,未发现椎弓根钉松动、断裂。结论椎弓根内固定结合椎体后凸成形术为骨质疏松性胸腰椎压缩性骨折的手术治疗提供了一种安全、可靠的方法,改善了机体的功能,提高了患者的生活质量。%Objective To investigate the pedicle screw fixation combined with kyphoplasty treatment of osteoporotic thoracolumbar fractures and clinical treatment ef ect. Methods The hospital incision posterior pedicle screw fixation combined with kyphoplasty treatment of 13 cases of osteoporotic thoracolumbar vertebral compression fracture patients from February 2011 to February 2012 The patients were fol owed up for 24 months, after review of the thoracic and lumbar lateral radiographs. Preoperative and postoperative 4D, the last fol ow-up, the Oswestry Disability Index score (oswestry disability index, ODI), X-ray measurement the vertebral sagit al index (sagit al index, SI) and the Cobb angle (SI =vertebral edge height /posterior margin height), fixed and the injured vertebra stable and function recovery observed. Results Al patients had happened leakage of bone cement, the lack of neurological symptoms. 13 patients, 12 patients were an average of 20 months fol ow

  20. 人工骨或自体骨移植联合椎弓根钉内固定修复脊柱结核%Artificial bone or autologous bone grafting combined with pedicle screw fixation for repair of spinal tuberculosis

    Institute of Scientific and Technical Information of China (English)

    姜棚菲; 翟文斌

    2015-01-01

    BACKGROUND:With the development of fixation materials and technology, scholars began to use artificial bone materials combined with pedicle screw fixation in the repair of spinal tuberculosis. OBJECTIVE: To summarize the characteristics of artificial bone materials combined with pedicle screw fixation in the repair of spinal tuberculosis. METHODS:The literatures about artificial bone graft materials in repair of spinal tuberculosis were retrieved from CNKI and PubMed database during 1985 to 2014 by computer. The keywords were “spinal tuberculosis, bone transplantation, internal fixation” in Chinese and English, respectively. RESULTS AND CONCLUSION:In the repair of spinal tuberculosis using artificial bone materials combined with pedicle screw fixation, autologous bone is the gold standard for bone grafting, presenting with no immune rejection. To avoid the occurrence of limited bone mass, pain and other complications, however, artificial bone materials have been extensively studied. Currently used artificial materials mainly include titanium and its aloys, hydroxyapatite composites and medical calcium sulfate, which al have good biocompatibility. But there are stil certain limitations and shortcomings.%背景:随着内固定材料和内固定技术的发展,越来越多的国内外学者开始应用人工骨材料联合椎弓根钉内固定修复脊柱结核。目的:综述人工骨修复材料联合椎弓根内固定修复脊柱结核的特点。方法:应用计算机检索CNKI和PubMed数据库1985至2014年有关人工骨移植材料修复脊椎结核方面的文献,中文关键词为“脊椎结核、骨移植、内固定”,英文关键词为“Spinal tuberculosis,Bone graft,Fixation”。结果与结论:在骨修复材料联合椎弓根内固定修复脊柱结核中,自体骨是骨移植的金标准,无免疫排斥反应,但为了避免自体骨取骨量有限、取骨后疼痛等并发症的发生,人工骨材料得到了广泛

  1. Comparison of headless screws used in the treatment of proximal nonunion of scaphoid bone

    OpenAIRE

    Gereli, Arel; Nalbantoglu, Ufuk; Sener, Ismail Ugur; Kocaoglu, Barıs; Turkmen, Metin

    2010-01-01

    Screws with different levels of compression force are available for scaphoid fixation and it is known that the Acutrak screw generates greater compression than the Herbert screw. We retrospectively compared two types of headless compression screw for their effectiveness in the repair of scaphoid nonunion. Twenty-nine cases of proximal scaphoid nonunion were surgically treated with non-vascularised bone graft: the Acutrak screw was used in 17 patients and the cannulated Herbert screw in 12 pat...

  2. 腰椎内固定中两种椎弓根钉加强技术与骨水泥的应用%Two strengthening pedicle screw techniques and bone cement in lumbar internal fixation

    Institute of Scientific and Technical Information of China (English)

    江泽华; 朱如森; 袁建军; 邵高升; 张学利

    2013-01-01

    BACKGROUND:Screw loosening and shedding may occur after osteoporosis associated with lumbar degenerative disease treated with pedicle screw fixation. Application of pedicle screw enhanced with cured materials can improve the therapeutic effect. OBJECTIVE:To compare the clinical effect of pedicle screws enhanced with poly(methyl methacrylate) and injectable calcium sulfate cement in the lumbar internal fixation of osteoporosis. METHODS:Sixty-one patients diagnosed with osteoporosis combined with lumbar spondylolisthesis, lumbar spinal instability, and severe lumbar spinal stenosis were col ected. Al patients were divided into two groups according to the treatment method:poly(methyl methacrylate) bone cement enhanced pedicle screw group and calcium sulfate bone cement enhanced pedicle screw group. RESULTS AND CONCLUSION:There were no significant differences in the operation time, blood loss, preoperative and postoperative visual analog scale score, Japanese Orthopedic Association scores and the Japanese Orthopedic Association score improvement rate between two groups (P>0.05). The results showed that two patients had bone cement leakage in poly(methyl methacrylate) group which had no neurological symptoms caused by new symptoms during fol ow-up period. The bone mineral density was not improved gradual y in poly(methyl methacrylate) group with fol ow-up time prolonging;however, in calcium sulfate group, the bone mineral density was increased significantly after treatment, and the change of bone mineral density was linearly related with Japanese Orthopaedic Association score improvement rate in calcium sulfate group. No screw loosening, pul ing out or neurological dysfunction occurred in both groups. The results indicate that like poly(methyl methacrylate), balcium sulfate bone cement can increase the stability of pedicle screws.%背景:骨质疏松伴腰椎退行性病变行椎弓根钉固定骨质疏松的椎体后可能会出现螺钉的松动、脱落,使用

  3. Biomechanical evaluation of screw and plate fixation in pelvic fractures%螺钉与钢板在骨盆骨折置入内固定应用中的生物力学评价

    Institute of Scientific and Technical Information of China (English)

    赵艳

    2011-01-01

    ofpelvic fractures and play a very important role in the final choice of treatment. Anatomic reduction and solid fixation of pelvicfractures as well as screws and plate internal fixation are very important. To develop an implant with small wound, low infectionrate, stable fixation and good compatibility is the current direction in the treatment of unstable pelvic fractures.

  4. Loosening torque of Universal Abutment screws after cyclic loading: influence of tightening technique and screw coating

    OpenAIRE

    Bacchi, Atais; Regalin, Alexandre; Bhering, Claudia Lopes Brilhante; Alessandretti, Rodrigo; Spazzin, Aloisio Oro

    2015-01-01

    PURPOSE The purpose of this study was to evaluate the influence of tightening technique and the screw coating on the loosening torque of screws used for Universal Abutment fixation after cyclic loading. MATERIALS AND METHODS Forty implants (Titamax Ti Cortical, HE, Neodent) (n=10) were submerged in acrylic resin and four tightening techniques for Universal Abutment fixation were evaluated: A - torque with 32 Ncm (control); B - torque with 32 Ncm holding the torque meter for 20 seconds; C - to...

  5. Biomechanics study of interal fixation with hollow compression screw and composite calcium phosphate cement of osteoporotic femoral neck%复合磷酸钙骨水泥强化骨质疏松股骨颈加压空心螺钉的生物力学研究

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Objective To evaluate the biomechanics of hollow compression screw in the osteoporotic femoral neck with composite calcium phosphate cement (CCPC).Methods Sixteen femurs of superior segment were randomly divided into two groups: augmentation group and non augmentation group.CCPC was used in augmentation group.Result Augmentation with CCPC would improve the initial mobile force of hollow compression screw,the initial mobile force and the maximal axial pull out strength for augmentation group,non augmentation group increased from (192.7± 14.0)N and (202.8± 14.0)N to(328.5± 34.7)N and( 347.8± 31.2)N.There was significant difference of two groups(P< 0.01).Conclusion CCPC can enhance hollow compression screw fixation in osteoporotic femoral neck.

  6. Design and biomechanical study of a modified pedicle screw

    Institute of Scientific and Technical Information of China (English)

    LIU Tao; ZHENG Wen-jie; LI Chang-qing; LIU Guo-dong; ZHOU Yue

    2010-01-01

    Objective: In pedicle screw fixation,the heads of monoaxial screws need to be directed in the same straight line to accommodate the rod placement by backing out during operation, which decreases the insertional torque and internal fixation strength. While polyaxial screws facilitate the assembly of the connecting rod, but its ball-in-cup locking mechanism reduces the static compressive bending yield strength as compared with monoaxial screws. Our study aimed to assess the mechanical performance of a modified pedicle screw.Methods: In this study, the tail of the screw body of the modified pedicle screw was designed to be a cylindershaped structure that well matched the inner wall of the screw head and the screw head only rotated around the cyclinder. Monoaxial screws, modified screws and polyaxial screws were respectively assembled into 3 groups ofvertebrectomy models simulated by ultra high molecular weight polyethylene (UHMWPE) blocks. This model was developed according to a standard for destructive mechanical testing published by the American Society for Testing Materials (ASTM F1717-04). Each screw design had 6 subgroups, including 3 for static tension, load compression and torsion tests, and the rest for dynamic compression tests. In dynamic tests, the cyclic loads were 25%, 50%, and 75% of the compressive bending ultimate loads respectively.Yield load, yield ultimate load, yield stiffness, torsional stiffness, cycles to failure and modes of failure for the 3 types of screws were recorded. The results of modified screws were compared with those ofmonoaxial and polyaxial screws.Results: In static tests, results of bending stiffness,yield load, yield torque and torsional stiffness indicated no significant differences between the modified and monoaxial screws (P>0.05), but both differed significantly from those ofpolyaxial screws (P<0.05). In dynamic compression tests,both modified and monoaxial screws showed failures that occurred at the insertion point of screw

  7. Pullout strength of pedicle screws with cement augmentation in severe osteoporosis: A comparative study between cannulated screws with cement injection and solid screws with cement pre-filling

    Directory of Open Access Journals (Sweden)

    Lee Yen-Chen

    2011-02-01

    Full Text Available Abstract Background Pedicle screws with PMMA cement augmentation have been shown to significantly improve the fixation strength in a severely osteoporotic spine. However, the efficacy of screw fixation for different cement augmentation techniques, namely solid screws with retrograde cement pre-filling versus cannulated screws with cement injection through perforation, remains unknown. This study aimed to determine the difference in pullout strength between conical and cylindrical screws based on the aforementioned cement augmentation techniques. The potential loss of fixation upon partial screw removal after screw insertion was also examined. Method The Taguchi method with an L8 array was employed to determine the significance of design factors. Conical and cylindrical pedicle screws with solid or cannulated designs were installed using two different screw augmentation techniques: solid screws with retrograde cement pre-filling and cannulated screws with cement injection through perforation. Uniform synthetic bones (test block simulating severe osteoporosis were used to provide a platform for each screw design and cement augmentation technique. Pedicle screws at full insertion and after a 360-degree back-out from full insertion were then tested for axial pullout failure using a mechanical testing machine. Results The results revealed the following 1 Regardless of the screw outer geometry (conical or cylindrical, solid screws with retrograde cement pre-filling exhibited significantly higher pullout strength than did cannulated screws with cement injection through perforation (p = 0.0129 for conical screws; p = 0.005 for cylindrical screws. 2 For a given cement augmentation technique (screws without cement augmentation, cannulated screws with cement injection or solid screws with cement pre-filling, no significant difference in pullout strength was found between conical and cylindrical screws (p >0.05. 3 Cement infiltration into the open cell of

  8. 3D计算机导航下经椎弓根骨水泥增强螺钉的应用%Polymethylmethacrylate-augmented thoracolumbar pedicle screw fixation guided by the three-dimensional navigation in osteoporotic patients

    Institute of Scientific and Technical Information of China (English)

    袁强; 张贵林; 吴静晔; 行勇刚; 何达; 孙宇庆; 田伟

    2014-01-01

    Objective To evaluate the safety and efficacy of polymethylmethacrylate (PMMA) -augmented thoracolumbar pedicle screw fixation guided by three-dimensional (3D) navigation in the osteoporotic patients.Methods From January 2010 to January 2012,27 osteoporotic patients with a variety of spinal disorders underwent PMMA-augmented thoracolumbar pedicle screw fixation guided by 3D navigation.They were 3 men and 24 women,aged from 51 to 92 years (average,70.1 years).Their osteoporosis was all serious.PMMA leakage was evaluated intraoperatively and postoperatively.Screw loosening and bone fusion were evaluated radiographically after operation.The Japanese Orthopaedic Association (JOA) scores of the patients were compared between preoperation and one year postoperation.Results Altogether 149 pedicle screws were implanted in the 27 patients.One patient died of postoperative pneumonia and the rest 26 patients were followed up for more than 12 months.No pedicle cortex breach or cement leakage surrounding the pedicle cortex was observed.None of the patients complained of dyspnoea showing evidence of pulmonary embolism or iatrogenic neural injury.No obvious deterioration of related symptoms or functions was observed after operation.The pre-operative JOA score (18.2 ± 2.6 points) was significantly increased (25.1 ± 2.3 points) postoperation (t =16.996,P =0.000),with a mean therapeutic improvement rate of 39.6%.None of the patients showed loosening or displacement of the implants.Lateral X-ray films showed bone fusion in 20 patients (76.9%) at the 12-month follow-up Conclusion PMMA-augmented thoracolumbar pedicle screw fixation guided by 3D navigation is safe and effective for osteoporotic patients with a variety of spinal disorders,leading to favorable outcomes both clinically and radiologically.%目的 评价在3D计算机导航下经椎弓根骨水泥增强胸腰椎椎弓根螺钉内固定术的安全性和有效性. 方法 2010年1月至2012年1月27例不同脊柱疾患

  9. Analysis the Clinical Curtive Effect of Thoracic Lumbar Spine Fractures of Posterior Pedicle Screw Fixation Combined Bone Graft Surgery%脊柱胸腰段骨折行后路椎弓根螺钉内固定联合植骨手术的临床疗效分析

    Institute of Scientific and Technical Information of China (English)

    慕志广

    2016-01-01

    Objective To evaluate the clinical curative effect for joint posterior pedicle screw internal fixation bone graft surgery in treatment of thoracic lumbar spine fractures.Methods Selected 72 cases of thoracic lumbar spine fracture patients in our hospital, which were randomly divided into two groups, each group had 36 cases, control group with posterior pedicle screw internal fixation treatment, the observation group patients give posterior pedicle screw internal fixation with bone graft surgery therapy.ResultsAfter surgery, VAS score, Cobb Angle observation group were better than the control group (P<0.05), two groups of data difference was statistically signiifcant (P<0.05).Conclusion Posterior pedicle screw internal fixation with bone graft surgery therapy thoracic lumbar spine fracture effect is remarkable was statistically significant (P<0.05). Conclusion Posterior pedicle screw internal fixation with bone graft surgery therapy thoracic lumbar spine fracture effect is remarkable.%目的:探讨后路椎弓根螺钉内固定联合植骨手术治疗脊柱胸腰段骨折的临床疗效。方法将我院收治的72例脊柱胸腰段骨折患者随机分为两组,各36例。对照组单用后路椎弓根螺钉内固定治疗,观察组给予后路椎弓根螺钉内固定联合植骨手术治疗。结果手术后,观察组VAS评分、Cobb角均优于对照组(P<0.05),差异有统计学意义(P<0.05)。结论后路椎弓根螺钉内固定联合植骨手术治疗脊柱胸腰段骨折效果显著。

  10. 单侧椎间融合内固定治疗腰椎间盘突出症的手术效果%Surgical Effect of Unilateral Pedicle Screw Fixation and Lumbar Interbody Fusion in the Treatment of Lumbar Disc Herniation

    Institute of Scientific and Technical Information of China (English)

    李开雄; 邵玉凯; 郑晓刚; 郭金元; 肖卫; 欧艳春

    2016-01-01

    目的 分析椎间盘突出症椎间融合后单侧内固定的手术效果 .方法 随机选取2007年8月—2014年12月收治的腰椎间盘突出症患者68例,均给予椎间植骨融合术治疗,随机分为单侧内固定治疗的观察组(34例)和双侧内固定治疗的对照组(34例),观察与对比两组患者手术治疗情况. 结果 与对照组比较,观察组患者的手术时间、术中出血量 、术后引流量均低于对照组,差异有统计学意义(P<0.05);术后二组患者的椎间隙曲度、融合率以及JOA评分、MACMAB疗效评定的差异均无统计学意义. 结论 研究表明,单侧椎间融合内固定治疗手术创伤小,可取得与双侧手术相当的近远期疗效.%Objective To analyze the surgical effect of unilateral pedicle screw fixation and lumbar interbody fusion in the treatment of lumbar disc herniation. Methods 68 patients with lumbar disc herniation admitted from August 2007 to De-cember 2014 were randomly divided into the observation group and the control group with 34 cases in each. The observation group were treated by the unilateral pedicle screw fixation and lumbar interbody fusion, while the control group were treated by bilateral pedicle screw fixation and lumbar interbody fusion. And the surgical treatment effect of the two groups was ob-served and compared. Results Compared to the control group, the observation group had shorter operative time, less intra-operative blood loss and less postoperative drainage, the differences were statistically significant (P<0.05). The differences in intervertebral curvature, fusion rate, JOA score and result of MACMAB between the groups after surgery were not statistical-ly significant. Conclusion The study shows that for the treatment of lumbar disc herniation, unilateral pedicle screw fixation and lumbar interbody fusion have smaller trauma, but can obtain the same short-term and long-term effects as bilateral pedicle screw fixation and lumbar interbody fusion.

  11. 下胫腓联合螺钉治疗Maisonneuve骨折的疗效%Fixation of inferior tibiofibular syndesmosis by screw for Maisonneuve fracture

    Institute of Scientific and Technical Information of China (English)

    叶秀章; 施继飞; 敖荣广; 丁惠锋; 周成欢; 禹宝庆

    2014-01-01

    背景:Maisonneuve骨折临床上十分少见,如果处理不当可导致踝关节不稳定。目的:探讨Maisonneuve骨折的损伤机制、诊断、治疗及临床治疗效果。  方法:回顾性分析2009年8月至2012年10月,手术治疗Maisonneuve骨折19例,男15例,女4例;年龄30~68岁,平均42.2岁。骨折均为Lauge-Hansen旋前外旋型,其中Ⅱ度损伤5例,Ⅲ度损伤6例,Ⅳ度损伤8例。手术均采用2枚皮质骨位置螺钉,三层皮质平行踝关节面固定下胫腓联合韧带。随访时采用AOFAS评分评估踝关节功能恢复情况。  结果:19例患者均获随访,随访时间6~65个月,平均50个月,骨折均愈合。末次随访时AOFAS评分平均94.7分(75~97分),其中优15例,良4例。  结论:Maisonneuve骨折是一种严重的不稳定性踝关节骨折,由于其骨折的特殊性,易致误诊及漏诊。手术治疗可恢复下胫腓关节的正常解剖关系以及踝穴的匹配,对预后起决定作用。%Background:The Maisonneuve fracture is rare in clinic, and improper management can lead to instability in the ankle. Objective:To explore the injury mechanism, diagnosis and treatment of Maisonneuve fracture. Methods: A retrospective analysis was done in 19 patients who suffered from Maisonneuve fracture and were treated be-tween August 2009 and October 2012. There were 15 males and 4 females with a mean age of 42.2 years (range, 30-68 years). According to Lauge-Hansen classification, there were 5 cases with gradeⅡpronate-extorsion injury, 6 with gradeⅢpronate-extorsion injury and 8 with gradeⅣpronate-extorsion injury.All fractures were fixed with 2 cortical positioning screws. All screws engaged 3 cortices above the ankle joint and parallel to the tibial plafond. AOFAS score was used to eval-uate ankle joint function during follow up. Results:All the patients were followed up for 50 months on average (range, 6-65 months). Bony union was

  12. Finite element analysis of bridge combined fixation system and the locking plate-screw system on the application for femoral fractures%桥接组合式内固定系统与锁定接骨板钉系统在股骨骨折应用中的有限元分析

    Institute of Scientific and Technical Information of China (English)

    熊鹰; 李群辉; 柳百炼; 赵烽; 王大兴; 张仲子

    2012-01-01

    背景:桥接组合式内固定系统在人体骨折固定上,与锁定钢板相比效果如何,有待实验证实.目的:比较桥接组合式内固定系统与金属锁定接骨板钉系统固定股骨干骨折的生物力学特性.方法:对两种固定方式的有限元模型进行模拟加载,了解各模型中骨与内固定的应力分布和应变特点,并对结果加以分析.结果与结论:爬楼梯时接骨板锁定螺钉上的应力比步态时增48.6%,达到480 MPa,最大应力出现在中间锁定螺钉上.桥接系统中间联接棒上的最大应力比步态时大34.1%,最大值为373.9 MPa,出现在联接棒中间略远端附近;骨折区域上的应力桥接组合式内固定系统小于金属锁定接骨板钉系统.提示桥接组合式内固定系统较金属锁定接骨板钉系统具有更好的生物力学性能,固定更牢靠、利于骨折生长,是骨折内固定的一种更好选择.%BACKGROUND: The effect of the bridge combined fixation system for the fixation of bone fracture compared with locking plate system needs to be confirmed by experiment. OBJECTIVE: To compare the biomechanical properties of bridge combined fixation system and locking plate-screw system for the fixation of femoral fractures. METHODS: We used the finite element analysis method to analyze biomechanical characters of the femoral fractures fixed with the locking plate-screw system and bridge combined fixation system, such as the stress distribution and the strain characteristics of bone and fixation. RESULTS AND CONCLUSION: The stress on the locking plate screw when climbing stairs was increased for 48.6% compared with walking, the stress was 480 MPa and the maximum stress was on the middle of the locking plate-screw screws. The maximum stress on the middle of the bridge system when climbing was 34.1% larger than that when walking, the maximum stress was 373.9 MPa and occurred near the distal connection rod. The stress on the fracture area of bridge combined

  13. Periprosthetic fracture fixation in osteoporotic bone.

    Science.gov (United States)

    Lenz, Mark; Lehmann, Wolfgang; Wähnert, Dirk

    2016-06-01

    Fixation techniques of periprosthetic fractures are far from ideal although the number of this entity is rising. The presence of an intramedullary implant generates its own fracture characteristics since stiffness is altered along the bone shaft and certain implant combinations affect load resistance of the bone. Influencing factors are cement fixation of the implant, intramedullary locking and extramedullary or intramedullary localization of the implant and the cortical thickness of the surrounding bone. Cerclage wires are ideally suited to fix radially displaced fragments around an intramedullary implant but they are susceptible to axial and torsional load. Screws should be added if these forces have to be neutralized. Stability of the screw fixation itself can be enhanced by embracement configuration around the intramedullary implant. Poor bone stock quality, often being present in metaphyseal areas limits screw fixation. Cement augmentation is an attractive option in this field to enhance screw purchase. PMID:27338227

  14. Mechanics research of bone cement augmentation on pedicle screw in revision of internal lumbar fixation%椎弓根螺钉骨水泥强化技术在腰椎内固定翻修手术中的力学研究

    Institute of Scientific and Technical Information of China (English)

    陈路; 廖琦; 龚玉琴

    2014-01-01

    目的:评价骨水泥强化技术在钉道扩大时对椎弓根螺钉固定强度的影响,为腰椎内固定翻修选择可靠的补救技术提供依据。方法选用成人尸体腰椎标本40个,观察组进行骨水泥强化,对照组普通方法置钉,进行生物力学检测。结果两种固定方法的最大轴向拔出力及最大旋出扭矩具有显著性差异(P<0.001),并提示弱相关。结论(1)在腰椎内固定翻修手术中,对椎弓根螺钉进行骨水泥强化可以有效提高椎弓根螺钉的固定强度。(2)钉道本身的骨质量对进行强化后的椎弓根螺钉固定强度影响有限。%Objective To evaluate the effect of bone cement augmentation technique on fixation strength of pedicle screw dur-ing trajectory expansion,to provide the basis of reliable remedial technique selection for revision of internal lumbar fixation.Methods A total of 40 lumbar vertebrae and 80 pedicles were obtained to stimulate the trajectory of pedicle needing revision after internal lumbar fixation surgery. 40 lumbar vertebrae were randomly divided into Group A and Group B ,with 20 simple fixed sides and 20 augmented fixed sides in each group. In Group A,pedicles on both sides of all the specimens were determined for the maximum axial pullout of strength;while in Group B,pedicles on both sides of all the specimens were detected for the maximum rotary torque,and differences between the two sides were compared. Results (1) There was significant difference between the two fixations,indicating a weak correlation. Conclusion (1)It was confirmed that in revision of internal lumbar fixation,bone cement augmentation on pedicle screw can effectively improve the strength of pedicle screw. (2)Maximum axial pullout of strength and maximum rotary torque in reinforced group were weakly correlated with those in the control group ,suggesting the bone quality of the trajectory had limited influence on the strength of reinforced pedicle screw

  15. Biomechanical impact of C2 pedicle screw length in an atlantoaxial fusion construct

    OpenAIRE

    Risheng Xu; Mohamad Bydon; Mohamed Macki; Belkoff, Stephen M.; Langdale, Evan R.; Kelly McGovern; Jean-Paul Wolinsky; Gokalsan, Ziya L.; Ali Bydon

    2014-01-01

    Background: Posterior, atlantoaxial (AA) fusions of the cervical spine may include either standard (26 mm) or short (16 mm) C2 pedicle screws. This manuscript focused on an in vitro biomechanical comparison of standard versus short C2 pedicle screws to perform posterior C1-C2 AA fusions. Methods: Twelve human cadaveric spines underwent C1 lateral mass screw and standard C2 pedicle screw (n = 6) versus short C2 pedicle screw (n = 6) fixation. Six additional controls were not instrumented. ...

  16. 拉力螺钉辅加抗滑钢板内固定治疗Hoffa骨折%Internal fixation with lag screws plus an auxiliary anti-sliding plate for the treatment of Hoffa fractures

    Institute of Scientific and Technical Information of China (English)

    徐培; 孙杰; 袁天祥; 马宝通

    2012-01-01

    Objective To investigate the clinical efficacy of internal fixation with lag screws plus an auxiliary sliding plate for the treatment of Hoffa fractures.Methods A retrospective analysis was made for 12 patients (14 condyles) with Hoffa fracture who had been treated in our hospital from December 2007 through November 2011.They were 8 males (10 condyles) and 4 females (4 condyles),with an average age of 36.2 years (range,from 20 to 61 years).By the Hoffa classification,6 cases were medial condylar fractures,4 lateral condylar fractures and 2 bicondylar fractures.By the AO/OTA classification,10 cases were type 33B32 and 2 type 33B33.By Letenneur's classification,7 condyles were type Ⅰ,one condyle was type Ⅱ and 6 condyles were type Ⅲ.There were 2 open fractures and 10 closed ones.Femoral shaft fracture was complicated in one case,proximal tibia fracture in 3 cases,ankle fracture in one,injury to the knee extensor mechanism in 2,cruciate ligament injury in 4,medial collateral ligament injury in one,and meniscus injury in 3.The time from injury to surgery averaged 3.2 days (from 2 hours to 7 days).All fractures were reduced under direct vision and fixated with cancellous lag screws plus an additional anti-sliding plate.Results All the patients were followed for 6 to 54 months (average,20.3 months).Union was achieved in all patients after an average time of 16.6 weeks (from 11 to 23 weeks).No implant failure or fracture displacement occurred.Incision infection and incision disunion occurred in one case each,but both were cured after intensive care.According to Letenneur's functional assessment,11 cases were excellent or good and one case was fair,giving a good to excellent rate of 91.7%.Conclusions Open reduction and internal fixation with lag screws and an additional anti-sliding plate may result in excellent results for Hoffa fractures.The key to a successful surgery is an appropriate approach,anatomic reduction and rigid fixation.%目的 探讨拉力螺钉辅

  17. To investigate the clinical effect of single screw internal fixation in the treatment of mandibular condyle sagittal fracture%探讨单螺钉内固定治疗下颌骨髁突矢状骨折的临床效果

    Institute of Scientific and Technical Information of China (English)

    张文兵

    2016-01-01

    目的:分析单螺钉内固定在下颌骨髁突矢状骨折的治疗中的临床效果.方法:收治髁突矢状骨折患者 100例,分两组,各50例.观察组实施单螺钉内固定治疗,对照组实施颌间牵引复位固定治疗.结果:观察组颞下颌关节功能障碍评分和并发症的发生率显著优于对照组(P<0.05).结论:在下颌骨髁突矢状骨折的治疗中,单螺钉内固定可以有效地缓解患者的颞下颌关节功能障碍,减少并发症.%Objective:To analyse the clinical effect of single screw internal fixation in the treatment of mandibular condyle sagittal fracture.Methods:100 patients with sagittal condylar fracture were selected,they were divided into two groups,each in 50 cases.The observation group was treated with single screw internal fixation,and the control group was treated with traction reduction and fixation.Results:The score of the temporomandibular joint dysfunction score and the incidence of complications in the observation group were significantly higher than those in the control group(P<0.05).Conclusion:In the treatment of mandibular condyle sagittal fracture,single screw internal fixation can effectively relieve patients of temporomandibular joint dysfunction, reduce complications.

  18. Comparative study of safety and efficacy of electrocautery blade with cold scalpel blade for skin opening during fixation of fracture of forearm bone with plate and screws

    Directory of Open Access Journals (Sweden)

    K T Madhukar

    2012-01-01

    Full Text Available Introduction: The art of performing surgeries have improved in recent years with the development of various electrosurgical devices assisting surgeons in performing safer surgeries with better outcomes. Skin incision has traditionally been made with a standard scalpel blade with good primary healing end results of the wound. The electrocautery has been used safely in performing deeper dissections. Use of electrocautery in skin incision has been discouraged in the past for the fear of cutaneous scarring, wound dehiscence, and infections particularly in orthopedic surgeries using internal implants. A review of the literature shows not many studies have been conducted to evaluate the safety and efficacy of electrocautery in skin incisions during orthopedic surgeries using internal implants. Aim: A prospective study was conducted in a tertiary care hospital with the aim to determine whether an electrocautery blade can be used safely for skin incisions. Materials and Methods: Sixty-two patients with single-bone fracture of the forearm undergoing open reduction and internal fixation received one-half of the incision with a standard scalpel blade and another half with electrocautery in pure cutting mode randomly. Analysis: Wounds were compared on operating day for any physical changes and on days 3, 5, and 12, and again on 3 rd and 6 weeks follow-up to know any difference in skin healing between the incised wounds of the two halves. Results: No evidence of any difference in healing of the two halves of skin incision was noted. There was also no increased risk of wound scarring, dehiscence, or infection with electrocautery incision when compared with standard scalpel incision. The time taken for skin incision with electrocautery was significantly less when compared with cold scalpel incision. Conclusion: We propose that electrocautery can be safely used for performing skin incision, with comparable results to that of a standard scalpel skin incision.

  19. Clinical application of augmented pedicle screw fixation with bone cement in lumber spondylolisthesis accompanied with osteoporosis%骨水泥强化椎弓根螺钉在腰椎滑脱伴骨质疏松椎体中的临床应用

    Institute of Scientific and Technical Information of China (English)

    李鹏; 毛克亚; 王岩; 肖嵩华; 张永刚; 张西峰; 张雪松; 程自申; 毛克政

    2011-01-01

    目的 探讨骨水泥强化椎弓根螺钉在腰椎滑脱伴骨质疏松患者的手术方法和疗效.方法 2008年7月至2010年11月年期间收治腰椎滑脱伴骨质疏松患者12例,平均68岁.骨质疏松按Jikei分级Ⅱ级4例,Ⅲ级8例.所有患者行经椎弓根螺钉内固定,术中采用骨水泥强化提高螺钉稳定性,植入椎弓根螺钉共26枚,观察椎弓根螺钉术中及术后的稳定性.结果 患者未发生手术并发症,腰腿痛症状改善明显,术后VAS评分较术前比较改善明显.12例患者均获得随访,随访时间8-16个月,平均14个月.12例均获得骨性融合,X线片显示内固定无松动、断裂或脱落,螺钉周围未见透亮线出现.结论 经椎弓根骨水泥强化椎弓根螺钉,固化椎体的同时增加了椎弓根螺钉界面把持力,能够满足腰椎滑脱伴骨质疏松患者脊椎后路固定手术对力学稳定的要求.%Objective To explore the surgical method and efficacy of augmented pedicle screw fixation with bone cement for the treatment of lumber spondyiolisthesis accompanied with osteoporosis. Methods Twelve lumber spondyiolisthesis patients accompanied with osteoporosis were collected and treated from July 2008 to November 2010, with an average age of 68 years old. According to Jikei scale for osteoporosis, 4 patients were in stage II and 8 patients were in stage III. All patients were treated with internal fixations of pedicle screws and the stabilities of screws were augmented by bone cement augment during operations. Twenty-six pedicle screws were instrumented in this study. The stabilities of pedicle screws during and after the operation were observed. Results There were no operative complications. The symptoms of waist and leg pain were clearly alleviated. The VAS scores after operations were clearly ameliorated compared to those before the operation. All 12 patients were followed up for 8-16 months, with a mean of 14 months. All 12 patients achieved bone unions. The X

  20. Biomechanical analysis on transverse tibial fixation in anterior cruciate ligament reconstructions☆

    OpenAIRE

    Edmar Stieven Filho; Mariane Henseler Damaceno Mendes; Stephanie Claudino; Filipe Baracho; Paulo César Borges; Luiz Antonio Munhoz da Cunha

    2015-01-01

    OBJECTIVE: To verify whether the combination of tibial cross pin fixation and femoral screw fixation presents biomechanical advantages when compared to femoral cross pin fixation and tibial screw fixation for the reconstruction of the anterior cruciate ligament (ACL).METHODS: Thirty-eight porcine knees and bovine extensor digitorum tendons were used as the graft materials. The tests were performed in three groups: (1) standard, used fourteen knees, and the grafts were fixated with the combina...

  1. Augmentation of pedicle screw fixation with polymethylmethacrylate in the osteoporotic spine:an in vitro biomechanical study%聚甲基丙烯酸甲酯强化对骨质疏松椎弓根螺钉固定的生物力学作用

    Institute of Scientific and Technical Information of China (English)

    樊仕才; 朱青安; 王柏川; 赵卫东; 周燕莉; 金大地; 刘大庸

    2001-01-01

    Objective To ascertain whether augmentation with polymethylmethacrylate(PMMA) bone cement can enhance pedicle screw fixation in the osteoporotic spine. Methods Sixteen cadaveric thoracolumbar vertebral bodies were obtained from 6 fresh frozen old females spines(T10- L5)at random and BMD were evaluated using DEXA. One pedicle screw of 6mm diameter (CCD) was implanted (one side). The maximum torque force was measured using torque wrench. The screws were pulled out from the vertebrae at 5 mm/min. A pedicle pilot hole was created using 3.5mm drill (the other side) and vertebral body was augmented with PMMA bone cement. Two CCD screws were implanted bilaterally. The screws were pulled out two hours later and pull out force were recorded. Results Average BMD was (0.445± 0.019)g/cm2 and the maximum torque force was (0.525± 0.104)Nm. The pull out strength of pedicle screw fixation following augmentation and restoration with PMMA averaged 310% greater than that of not augmented. Conclusion Augmentation or restoration with PMMA offered a significantly increase of strength for pedicle screw fixation in the osteoporotic spine, people with osteoporosis who must use pedicle screw fixation should augment pedicle screw with PMMA bone cement.%目的探讨聚甲基丙烯酸甲酯(polymethylmethacrylate,PMMA)骨水泥强化椎弓根螺钉的方法和评价PMMA强化骨质疏松椎弓根螺钉后的生物力学性质。方法6具新鲜老年女性胸腰段骨质疏松脊柱标本(T10~L5),使用双能X线骨密度吸收仪测试每个椎体的骨密度,随机取16个椎体(32侧椎弓根),一侧椎弓根拧入CCD螺钉,测量最大旋入力偶矩后拔出螺钉作为正常对照组,用PMMA骨水泥强化椎弓根螺钉作为修复固定组,行螺钉拔出试验;另一侧经导孔直接强化椎弓根螺钉后拔出作为强化固定组,记录三组螺钉的最大轴向拔出力。结果椎体平均骨密度为(0.445±0.019)g/cm2;螺

  2. Close reduction and percutaneous internal fixation with hollow screw in treatment of posterior malleolus fractures%闭合复位经皮空心螺钉内固定治疗后踝骨折

    Institute of Scientific and Technical Information of China (English)

    冯青; 许效坤; 苏海涛

    2011-01-01

    目的探讨闭合复位经皮空心螺钉内固定选择性治疗后踝骨折的手术方法、适应证及临床效果.方法回顾性分析2004年7月至2010年4月期间采用闭合复位经皮空心拉力螺钉内固定治疗42例成人后踝骨折的临床资料,其中旋后-外旋型28例,旋前-外旋型6例,旋前-外展型8例.采用X线片评估骨折愈合率,采用美国足踝骨科协会(AOFAS)推荐的足踝评分系统评估踝关节功能.结果平均随访22个月(6~75个月),骨折愈合时间为6~12周.按AOFAS足踝评分系统评分,平均为96分(78~100分),优41例,可1例,优良率为97.6%.结论闭合复位经皮空心螺钉内固定是一种可用于治疗后踝骨折的微创术式,具有骨折愈合快,骨折愈合率高,踝关节功能好的优点.%Objective To investigate the indication and efficacy of close reduction and percutaneous internal fixation with hollow screws in the treatment of posterior malleolus fractures. Methods The clinical data of 42 cases of posterior malleolus fracture treated by this method from July,2004 to April ,2010 were retrospectively analyzed,including 28 cases of supination-eversion fractures,6 cases of pronation-eversion fractures and 8 cases of pronation-abduction fractures. The fracture healing rate was assessed by X-ray film and the function of the ankle joint was evaluated by foot and ankle scoring system recommended by American Orthopedic Foot & Ankle Society ( AOFAS). Results The followup averaged for 22 months (6 ~75 months). The fracture healing time ranged form 6 to 12 weeks. According to the results of foot and ankle function scores, the average score was 96 points (78 ~ 100 points), including 41 cases of excellence and 1 case of fairness, the rate of excellent and good amounting to 97.6%. Conclusion With the advantage of quick recovery, high healing rate and better healing effect, close reduction and percutaneous internal fixation with hollow screws is feasible in the treatment of

  3. Experimental study of pedicle screw stability on low BMD vertebrae

    International Nuclear Information System (INIS)

    Objective: To conduct biomechanical study of different pedicle screws stability on spinal specimen, discuss the relationship between design parameter of screw, insertion torgue and BMD, establish the theoretical foundation for application of pedicle screw on osteoporotic patients. Methods: Six fixed lumbar cadavers were collected, the effects of design parameter, insertion torque and etc on fixation stability were determined under various BMD by using biomechanical ways. Results: According to in vitro study: (1) There was a significant difference among pullout strength of all screws (P2>U1>SF1>SF2>RF. Conclusions: There is a close correlated between type of screw, BMD and stability. The U-type screw displays the best fixation effect on specimen of low BMD. (authors)

  4. Iliosacral Screw Placement With Local Anesthesia Using C T Scan

    Directory of Open Access Journals (Sweden)

    Shahriar Kamrani R

    2003-07-01

    Full Text Available Ilio-sacral screw is a technique for posterior pelvic fixation. In spite of its benefits, it had not performed commonly in Iran because of its difficulties. We changed this technique to insert the screw under CT-Scan guide with lical anesthesia to increase image quality and decrease neurological complications and performed it in two patients. In both cases the screws were inserted in correct position without any complication."n"n 

  5. Torsional stability of interference screws derived from bovine bone - a biomechanical study

    Directory of Open Access Journals (Sweden)

    Schmitt Jan

    2010-05-01

    Full Text Available Abstract Background In the present biomechanical study, the torsional stability of different interference screws, made of bovine bone, was tested. Interference screws derived from bovine bone are a possible biological alternative to conventional metallic or bioabsorbable polymer interference screws. Methods In the first part of the study we compared the torsional stability of self-made 8 mm Interference screws (BC and a commercial 8 mm interference screw (Tutofix®. Furthermore, we compared the torsional strength of BC screws with different diameters. For screwing in, a hexagon head and an octagon head were tested. Maximum breaking torques in polymethyl methacrylate resin were recorded by means of an electronic torque screw driver. In the second part of the study the tibial part of a bone-patellar tendon-bone graft was fixed in porcine test specimens using an 8 mm BC screw and the maximum insertion torques were recorded. Each interference screw type was tested 5 times. Results There was no statistically significant difference between the different 8 mm interference screws (p = 0.121. Pairwise comparisons did not reveal statistically significant differences, either. It was demonstrated for the BC screws, that a larger screw diameter significantly leads to higher torsional stability (p = 9.779 × 10-5. Pairwise comparisons showed a significantly lower torsional stability for the 7 mm BC screw than for the 8 mm BC screw (p = 0.0079 and the 9 mm BC screw (p = 0.0079. Statistically significant differences between the 8 mm and the 9 mm BC screw could not be found (p = 0.15. During screwing into the tibial graft channel of the porcine specimens, insertion torques between 0.5 Nm and 3.2 Nm were recorded. In one case the hexagon head of a BC screw broke off during the last turn. Conclusions The BC screws show comparable torsional stability to Tutofix® interference screws. As expected the torsional strength of the screws increases significantly with the

  6. Robot assisted navigated drilling for percutaneous pedicle screw placement: A preliminary animal study

    Directory of Open Access Journals (Sweden)

    Hongwei Wang

    2015-01-01

    Conclusions: The preliminary study supports the view that computer assisted pedicle screw fixation using spinal robot is feasible and the robot can decrease the intraoperative fluoroscopy time during the minimally invasive pedicle screw fixation surgery. As spine robotic surgery is still in its infancy, further research in this field is worthwhile especially the accuracy of spine robot system should be improved.

  7. Bone cement-augmented pedicle screw fixation for lumbar spondylolisthesis combined with osteoporosis:1-year follow-up%骨水泥强化椎弓根螺钉置入固定骨质疏松性腰椎滑脱:1年随访

    Institute of Scientific and Technical Information of China (English)

    丁权; 陈勇

    2015-01-01

    BACKGROUND:For patients with lumbar spondylolisthesis combined with osteoporosis, appropriate fixation system for effective reset and good fixation stability is currently a hot issue of clinical concern. Pedicle screw screw-rod system after bone cement perfusion can achieve the effective fixation between pedicle screw system and the vertebral bone. OBJECTIVE:To observe the therapeutic effect of bone cement-augmented pedicle screw on patients with lumbar spondylolisthesis combined with osteoporosis. METHODS:17 cases of lumbar spondylolisthesis combined with osteoporosis were identified by bone density test. They received the posterior open reduction and internal fixation, and implanted with 68 bone cement-augmented pedicle screws. Their repair effects were observed by short-term fol ow-up. Patients were evaluated using low back pain Visual Analog Scale and lower limb Oswestry Disability Index before treatment, 1 week, 3 months and 1 year after treatment. Vertebral height, intervertebral height, screw loosening and bone cement leakage were observed using imaging. RESULTS AND CONCLUSION:Compared with pre-treatment, low back pain Visual Analog Scale score and lower limb Oswestry Disability Index were significantly improved at 1 week, 3 months and 1 year after treatment (P0.05), which indicated that clinical repair effect could be effectively maintained. At 3 months of fol ow-up, one screw loosening occurred in two patients. During fixation, mild bone cement leakage appeared in seven vertebral bodies with screw fixation, no symptoms or subsequent complications were observed. There were no significant differences in vertebral height and intervertebral height before and after treatment and during fol ow-up (P>0.05). These results suggest that bone cement-augmented pedicle screw for patients with lumbar spondylolisthesis combined with osteoporosis can effectively reset vertebral slippage, effectively provide good anti-pul-out force for a long term, and the effect was

  8. Arthroscopic Bony Bankart Repair Using Double-Threaded Headless Screw: A Case Report

    Directory of Open Access Journals (Sweden)

    Takeshi Kokubu

    2012-01-01

    Full Text Available We present a case of arthroscopic fixation for bony Bankart lesion using a double-threaded cannulated screw. A 39-year-old man sustained a left shoulder injury from a motorcycle accident. Radiographs showed bony Bankart lesion and CT revealed 40% defect of glenoid articular surface. Arthroscopic fixation was performed using double-threaded cannulated screw after the bony fragment was reduced by suturing the labrum at the edge with a suture anchor. Arthroscopic bony Bankart repair using double-threaded cannulated screw fixation is effective because compression force could be applied between bony fragments and the screw head is not exposed in the glenohumeral joint.

  9. A new concept for implant fixation: bone-to-bone biologic fixation

    OpenAIRE

    D-Y Kim; J-R Kim; KY Jang; K-B Lee

    2015-01-01

    Many attempts have been made to reduce complications of bone implant, such as pedicle screw loosening. To address this problem, the authors suggest a new concept of bone-to-bone biologic fixation using recombinant human bone morphogenetic protein-2 (rhBMP-2)-loaded cannulated pedicle screws. Recombinant human bone morphogenetic protein-2 is an osteoinductive cytokine. Four types of titanium pedicle screws were tested (uncannulated, cannulated with no loading, beta-tricalcium phosphate (TCP)-l...

  10. 金属铰链外固定支架与有限针钉置入内固定治疗肘关节"恐怖三联征"%Metal hinged elbow external fixator combined with pins and screw fixation for treatment of "terrible triad of the elbow"

    Institute of Scientific and Technical Information of China (English)

    赵王林; 杨海韵; 吴征杰

    2011-01-01

    BACKGROUND: The previous treatment of elbow dislocations associated with radial head and coronoid fractures (terrible triad of the elbow) are often poor because of recu rrent instability, stiffness and other complications from prolonged immobilization.OBJECTIVE: To observe the clinical efficacy on treatment of the terrible triad of the elbow with hinged elbow external fixator with limited internal fixation .METHODS: A total of 14 cases received the terrible triad of the elbow treatment from April 2006 to June 2010 at Foshan Hospital of Traditional Chinese Medicine, were collected. The patients were treated with metal hinged elbow external fixator combined with pin and screw fixation. All patients were followed up for ≥ 5 months, complained of illness, elbow range of motion, the forearm rotating activity, joint stability and radiographs were recorded. Mayo Elbow Performance Score (MEPS) was used to evaluate the function of elbow.RESULTS AND CONCLUSION: No patient complained pain, instability and no superficial and deep tissue infections occurred at the last follow-up. The mean fracture healing time was (11.30±3.25) weeks. The average range of elbow flexion-extension were (125.42±19.66)° (75°-145°), and forearm pronation-supination were (135.43±17.07)° (80°-150°). Two cases of brain injury occurred a small amount of ossification in anterior cubital soft tissue, did not affect the joint motion. The functional outcome was excellent in 7, good in 5 and fair in 2 according to MEPS, the fine and good rate was 86%. Hinged elbow external fixator combined with pins and screw fixation can improve the initial stability, conducive to the elbow of the center of concentric reduction and soft tissue repair and facilitate early functional exercise, eliminate the problem of secondary surgery.%背景:以往治疗肘关节后脱位伴桡骨头及尺骨冠状突骨折(肘关节恐怖三联征)的手术方法需要长期制动而常常导致肘关节复发性不稳定、

  11. Vertebral and inter-vertebral screw fixation for treating thoracolumbar compression fracture:a long-term follow-up of spinal stability%经伤椎和跨伤椎螺钉置入固定胸腰椎压缩性骨折:脊柱稳定性长期随访

    Institute of Scientific and Technical Information of China (English)

    谢申; 祝少博

    2016-01-01

    BACKGROUND: Posterior pedicle screw fixation is a common method for treatment of thoracolumbar compression fractures. The fixation method contains long-segment fixation, short-segment fixation and vertebral fixation. Clinical effects of vertebral fixation and inter-vertebral short-segment fixation for treating thoracolumbar fractures remain unclear. OBJECTIVE: To compare the stability of posterior vertebral fixation and inter-vertebral pedicle screw fixation for treating thoracolumbar compression fractures. METHODS: Clinical data of 46 patients with thoracolumbar compression fractures were retrospectively analyzed. According to the fixation methods, they were divided into the vertebral fixation group (n=21) and inter-vertebral fixation group (n=25). The operation time, intraoperative bleeding, intraoperative blood transfusion, the time of lying in bed, vertebral Cobb angle, anterior vertebral height and visual analog scores were evaluated for a long time. RESULTS AND CONCLUSION: (1) During repair, in both groups, operation time, intraoperative bleeding and intraoperative blood transfusion were better in the inter-vertebral fixation group than in the vertebral fixation group (P < 0.05-0.01). The time of lying in bed was better in the vertebral fixation group than in inter-vertebral fixation group (P < 0.01). (2) No significant difference in Cobb angle and anterior vertebral height was detected before and after treatment and during repair in both groups, but final fol ow-up and fol ow-up loss were better in the vertebral fixation group than in inter-vertebral fixation group (P < 0.05-0.01). (3) No significant difference in visual analog scores was detected before and after treatment in both groups. Visual analog scores were better in the vertebral fixation group than in the inter-vertebral fixation group (P <0.01). (4) These results suggested that the two fixation methods obtained satisfactory repair effects in long-term fol ow-up. The dominance in maintaining the

  12. Arthroscopic fixation with screws versus sutures for anterior cruciate ligament tibial avulsion fractures%关节镜下螺钉与缝线固定前交叉韧带胫骨止点撕脱骨折的疗效比较

    Institute of Scientific and Technical Information of China (English)

    王庆; 黄华扬; 张涛; 沈洪园; 郑小飞; 李凭跃; 区永亮

    2015-01-01

    Objective To compare the curative effects between arthroscopic screw and suture fixations for anterior cruciate ligament (ACL) tibial avulsion fractures.Methods From November 2007 to November 2012,41 patients with ACL tibial avulsion fracture underwent arthroscopy at our department.They were 32 males and 9 females,8 to 43 years of age (average,18.3 years).By the Meyers-McKeever-Zaricznyj classification,12 cases were type Ⅱ and 29 type Ⅲ.There were 19 cases in the screw fixation group,including 14 males and 5 females,9 to 42 years of age (average,18.9 years).The suture fixation group had 22cases,including 16 males and 6 females,8 to 43 years of age (average,17.8 years).Operation time,knee range of motion (ROM),case of flexion contracture,Lysholm score,international knee documentation committee (IKDC) score,and side-to-side mobile difference by KT-2000 were evaluated.The 2 groups were similar in age,gender,fracture type and time from injury to surgery (P > 0.05).Results The operation time for the suture fixation group (58.9 ±6.7 min) was significantly longer than that for the screw fixation group (51.6±6.2 min) (P < 0.05).There were no significant differences between the 2 groups regarding the Lysholm score (96.2 ± 2.83 for the screw fixation group versus 95.5 ± 2.6 for the suture fixation group),the IKDC score (91.4 ± 6.4 for the screw fixation group versus 88.1 ± 7.5 for the suture fixation group),the side-to-side mobile difference by KT-2000 (2.7 ± 2.6 mm for the screw fixation group versus 2.8 ± 2.7 mm for the suture fixation group (P < 0.05).Flexion contracture of ≥ 5° occurred in 3 cases in the screw fixation group and 2 cases in the suture fixation group,showing no significant difference (P > 0.05).Conclusions In treatment of ACL tibial avulsion fractures of types Ⅱ and Ⅲ,there is no significant difference between arthroscopic screw fixation and suture fixation,because both methods can achieve good stability and functional recovery

  13. 不同前路中空加压螺纹钉内固定治疗Ⅱ型齿突骨折的生物力学评价%Biomechanical evaluation of internal fixation of different anterior canulated screws for the treatment of type odontoid fracture

    Institute of Scientific and Technical Information of China (English)

    韩国伟; 刘少喻; 赵卫东; 于滨生; 梁春祥; 陈柏龄; 李浩淼; 魏福鑫

    2009-01-01

    BACKGROUND:Antedor canulated screw has been considered an ideal method to treat odontoid fracture.OBJECTIVE:To compare the biomechanical properties of different anterior screws.DESIGN,TIME AND SETTING:A randomized contrast study was performed at the Biomechanics Laboratory of Southern Medical University from March to September 2006.MATERIALS:Double-thread canulated screws and single-thread canulated screws were made of titanium alloy and provided by Shuangyang Medical Apparatus Co.,Ltd.,Suzhou.METHODS:A total of head-neck complexes (C0-C3) which were collected from 20 corpses were maintained in formaldehyde for less than 3 months;thereafter,the muscles and ligaments were removed to obtain the axis specimens so as to make type Ⅱ odontoid fracture models.The fracture samples were individually treated with double-thread and single-thread canulated screws,with 10 samples for each group.MAIN OUTCOME MEASURES:The shear stiffness and the maximum resistance of the two kinds of screw were tested in this study.RESULTS:The shear stiffness of the double-thread screw group was significantly higher than the single-thread screw group (P<0.01 );however,there was no significant different in the maximum resistance between the two groups (P>0.05).CONCLUSION:Double-thread canulated screws have a strong biomechanical stability for treating odontoid fracture;therefore,the first choice of the internal fixation should be double-thread canuiated screws for patients with osteoporosis or those who are susceptible to expanded screw pathway during surgical procedures.%背景:目前前路中空加压螺钉固定被认为是治疗齿突骨折的较理想方法.目的:比较不同前路内固定螺钉的生物力学特性.设计、时间及地点:随机分组设计,对比观察,于2006-03/09在南方医科大学生物力学实验室完成.材料:双头螺纹中空加压螺钉和单头螺纹中空加压螺钉均为钛合金材料,由苏州双羊医疗器械有限公司生产制作.方法:20

  14. A Novel Blasted and Grooved Low Profile Pedicle Screw Able to Resist High Compression Bending Loads

    OpenAIRE

    Kuh, Sung-Uk; Kim, Young-Sung; Choi, Hong-June; Kim, Kyung-Hyun; Park, Jeong-Yoon; Jeong, Hyun-Yong; Chin, Dong-Kyu; Kim, Keun-Su; Yoon, Young-Sul; Lee, Yoon-Chul; Cho, Yong-Eun

    2012-01-01

    Objective Polyaxial pedicle screws are a safe, useful adjunct to transpedicular fixation. However, the large screw head size can cause soft tissue irritation, high rod positioning, and facet joint injury. However, the mechanical resistance provided by small and low profile pedicle screws is very limited. We therefore developed a novel, low profile pedicle screw using grooving and blasting treatment that is able to resist a high compression bending load. Methods We evaluated the compression be...

  15. Posterior cervical spine arthrodesis with laminar screws: a report of two cases

    OpenAIRE

    Nakanishi, Kazuo; Tanaka, Masato; Sugimoto, Yoshihisa; Ozaki,Toshifumi

    2007-01-01

    We performed fixation using laminar screws in 2 patients in whom lateral mass screws, pedicle screws or transarticular screws could not be inserted. One was a 56-year-old woman who had anterior atlantoaxial subluxation (AAS). When a guide wire was inserted using an imaging guide, the hole bled massively. We thought the re-insertion of a guide wire or screw would thus increase the risk of vascular injury, so we used laminar screws. The other case was an 18-year-old man who had a hangman fractu...

  16. Optimizing Stability in Femoral Neck Fracture Fixation.

    Science.gov (United States)

    Ye, Ye; Hao, Jiandong; Mauffrey, Cyril; Hammerberg, E Mark; Stahel, Philip F; Hak, David J

    2015-10-01

    Optimizing stability of femoral neck fracture fixation is important in obtaining a successful outcome. The mechanical problems and strategies for achieving optimal stability differ depending on patients' age and degree of osteoporosis. Femoral neck fractures in younger adults usually result from high-energy trauma and have a vertical fracture pattern. Strategies for optimizing fixation stability in this group include placing additional screws at right angles to the fracture plane and medial buttress plate augmentation. In elderly patients, screw position relative to the intact cortical femoral neck bone is of critical importance. Additional strategies for optimizing fixation stability in this group include the concept of length stable fixation, use of adjunctive calcium phosphate cement, and use of novel fixed angle fixation implants. PMID:26488776

  17. One-wayversusuniversal pedicle screw fixation for lumbar fractures:biomechanics%椎弓根单向螺钉及万向螺钉置入内固定修复腰椎骨折的生物力学比较

    Institute of Scientific and Technical Information of China (English)

    吕胜江; 付丽娟; 李红梅

    2016-01-01

    BACKGROUND:Previous studies have performed three-dimensional finite element analysis on lumbar fracture fixation. However, a few studies concerned three-dimensional finite element analysis of lumbar spinal pedicle screw fixation. OBJECTIVE:To analyze the biomechanical characteristics of one-way screw and universal screw fixation for lumbar fractures using finite element method. METHODS:Models of lumbar fractures treated with one-way screw and universal screw fixation were established. Three-dimensional finite element method was used to analyze and compare the maximum axial displacement, maximum bending degree, maximum stress on thepedicle screw fixation system and maximum stress of intervertebral disc in normal vertebral fracture model, one-way and universal pedicle screw fixation models. RESULTS AND CONCLUSION:(1) The maximum axial displacement at anteflexion, posterior extension, left lateral curvature and right lateral curvature was significantly lower in the one-way fixation group and universal fixation group than in the normal group (P  目的:以有限元法分析腰椎椎弓根单向螺钉及万向螺钉置入内固定修复腰椎骨折的生物力学特点。  方法:建立腰椎骨折椎弓根单向螺钉及万向螺钉内固定模型,以三维有限元法分析正常腰椎模型、腰椎骨折椎弓根单向螺钉及万向螺钉内固定模型的最大轴向位移、最大弯曲度、椎弓根螺钉固定系统上的最大应力以及椎间盘的最大应力,并进行对比分析。  结果与结论:①单向钉固定组和万向钉固定组在前屈、后伸、左侧弯和右侧弯时的最大轴向位移均明显低于正常腰椎组(P<0.05-0.01),万向钉固定组在以上各方位的最大轴向位移均低于单向钉固定组;②单向钉固定组和万向钉固定组在各方位的最大弯曲度均明显低于正常腰椎组(P<0.05-0.01),万向钉固定组在各方位时的最大弯曲度均低于单向钉固定组;

  18. Reinforcement of osteosynthesis screws with brushite cement.

    Science.gov (United States)

    Van Landuyt, P; Peter, B; Beluze, L; Lemaître, J

    1999-08-01

    The fixation of osteosynthesis screws remains a severe problem for fracture repair among osteoporotic patients. Polymethyl-methacrylate (PMMA) is routinely used to improve screw fixation, but this material has well-known drawbacks such as monomer toxicity, exothermic polymerization, and nonresorbability. Calcium phosphate cements have been developed for several years. Among these new bone substitution materials, brushite cements have the advantage of being injectable and resorbable. The aim of this study is to assess the reinforcement of osteosynthesis screws with brushite cement. Polyurethane foams, whose density is close to that of cancellous bone, were used as bone model. A hole was tapped in a foam sample, then brushite cement was injected. Trabecular osteosynthesis screws were inserted. After 24 h of aging in water, the stripping force was measured by a pull-out test. Screws (4.0 and 6.5 mm diameter) and two foam densities (0.14 and 0.28 g/cm3) were compared. Cements with varying solid/liquid ratios and xanthan contents were used in order to obtain the best screw reinforcement. During the pull-out test, the stripping force first increases to a maximum, then drops to a steady-state value until complete screw extraction. Both maximum force and plateau value increase drastically in the presence of cement. The highest stripping force is observed for 6.5-mm screws reinforced with cement in low-density foams. In this case, the stripping force is multiplied by 3.3 in the presence of cement. In a second experiment, cements with solid/liquid ratio ranging from 2.0 to 3.5 g/mL were used with 6.5-mm diameter screws. In some compositions, xanthan was added to improve injectability. The best results were obtained with 2.5 g/mL cement containing xanthan and with 3.0 g/mL cements without xanthan. A 0.9-kN maximal stripping force was observed with nonreinforced screws, while 1.9 kN was reached with reinforced screws. These first results are very promising regarding screw

  19. Surgical screw segmentation for mobile C-arm CT devices

    Science.gov (United States)

    Görres, Joseph; Brehler, Michael; Franke, Jochen; Wolf, Ivo; Vetter, Sven Y.; Grützner, Paul A.; Meinzer, Hans-Peter; Nabers, Diana

    2014-03-01

    Calcaneal fractures are commonly treated by open reduction and internal fixation. An anatomical reconstruction of involved joints is mandatory to prevent cartilage damage and premature arthritis. In order to avoid intraarticular screw placements, the use of mobile C-arm CT devices is required. However, for analyzing the screw placement in detail, a time-consuming human-computer interaction is necessary to navigate through 3D images and therefore to view a single screw in detail. Established interaction procedures of repeatedly positioning and rotating sectional planes are inconvenient and impede the intraoperative assessment of the screw positioning. To simplify the interaction with 3D images, we propose an automatic screw segmentation that allows for an immediate selection of relevant sectional planes. Our algorithm consists of three major steps. At first, cylindrical characteristics are determined from local gradient structures with the help of RANSAC. In a second step, a DBScan clustering algorithm is applied to group similar cylinder characteristics. Each detected cluster represents a screw, whose determined location is then refined by a cylinder-to-image registration in a third step. Our evaluation with 309 screws in 50 images shows robust and precise results. The algorithm detected 98% (303) of the screws correctly. Thirteen clusters led to falsely identified screws. The mean distance error for the screw tip was 0.8 +/- 0.8 mm and for the screw head 1.2 +/- 1 mm. The mean orientation error was 1.4 +/- 1.2 degrees.

  20. 骨水泥和纳米骨浆强化椎弓根螺钉植入固定骨质疏松椎体的生物力学特点%Bone cement and nano bone putty strengthen pedicle screw implantation in the fixation of osteoporotic vertebral body:biomechanical characteristics

    Institute of Scientific and Technical Information of China (English)

    卢小兵; 孟祥翔

    2015-01-01

    BACKGROUND:Nano bone putty and bone cement injection are two common methods to strengthen the fixation of pedicle screws, but there are relatively few reports on the comparison of their strengthening effects. OBJECTIVE:To compare the biomechanical characteristics of bone cement and nano bone putty strengthening pedicle screw implantation in the fixation of osteoporotic vertebral body. METHODS: Totaly 24 human cadaveric pedicles were obtained, which were al in line with osteoporosis standards, and randomly divided into 3 groups: control group (only implanted pedicle screws), bone cement group (first injected bone cement in the nail channel, and then implanted pedicle screws) and nano bone putty group (first injected nano bone putty in the nail channel, and then implanted pedicle screws). After 2 hours of implantation, the maximum axial pulout strength and the maximum rotation torque of specimens in each group were determined. RESULTS AND CONCLUSION:The maximum axial pulout strength and maximum rotation torque of the bone cement and the nano bone putty groups were greater than those of the control group (P < 0.05), and the maximum axial pulout strength and the maximum rotation torque of the bone cement group were greater than those of the nano bone putty group (P < 0.05). These results demonstrate that the maximum axial pulout strength and the maximum rotation torque of pedicle screw implantation in the fixation of osteoporotic vertebral body can be effectively improved by injection of bone cement and nano bone putty, and the strengthening effect of bone cement is more obvious. %背景:纳米骨浆和骨水泥注入是强化椎弓根螺钉固定的两种常用方法,但目前关于两种加强方法的强化效果比较的报道相对较少。目的:对比骨水泥或纳米骨浆强化椎弓根螺钉植入固定骨质疏松椎体的生物力学特点。方法:取24个人尸体椎弓根,均符合骨质疏松标准,随机均分为3组,对照组仅植

  1. Correção da cifose de Scheuermann: estudo comparativo da fixação híbrida com ganchos e parafusos versus fixação apenas com parafusos Corrección de la cifosis de Scheuermann: estudio comparativo de la fijación híbrida con ganchos y tornillos versus fijación solo con tornillos Correction of Scheuermann kyphosis: comparative study of hybrid fixation using hooks and screws versus screw-only fixation

    Directory of Open Access Journals (Sweden)

    Enguer Beraldo Garcia

    2009-12-01

    fijación solo con tornillos.OBJECTIVE: to evaluate the degree of correction of Sheuermann kyphosis, in 6 patients who were submitted to surgery using hybrid instrumentation comprised of hooks and screws (H, and 17 patients undergoing screw-only fixation (P. METHODS: 23 patients with Scheuermann kyphosis were submitted to surgical treatment using anterior and posterior approach. In the present study, we indicated surgical treatment for rigid kyphosis, varying between 60º and 105º. All patients presented a Risser signal above 4. Liberation and Fusion were realized through anterior approach, followed by fixation, deformity correction, and arthrodesis through posterior approach. RESULTS: in Group H, a preoperative kyphosis of 84.17º and a postoperative of 47.5º were observed. In Group P, a preoperative kyphosis of 80.35º and postoperative of 33.53º were observed. CONCLUSION: it was concluded that both types of fixation presented very satisfactory results, with screw only fixation being superior.

  2. Quantitative Anatomy of C7 Vertebra in Southern Chinese for Insertion of Lateral Mass Screws and Pedicle Screws

    Science.gov (United States)

    Chan, Chi Hin; Wong, Kam Kwong; Wong, Wing Cheung

    2016-01-01

    Study Design Retrospective study. Purpose To analyze the quantitative anatomy of C7 vertebra for insertion of lateral mass screws and pedicle screws in Southern Chinese patients. Overview of Literature C7 lateral mass is smaller when compared to other subaxial cervical levels, which limits the length of lateral mass screws that can be used. Some studies have suggested pedicle screws for better fixation. But, this option is limited by the narrow pedicle width. Methods We have obtained computed tomography (CT) cervical spine data in 0.625 mm slices from our radiology department. The patients were adults. CTs were from May to August, 2015. The lateral mass screw length was measured using Margerl's technique and pedicle width and pedicle screw trajectory were determined in three-dimensional reformated images. Results CT scans of cervical spines of 94 patients were obtained and 188 lateral masses and pedicles of C7 vertebrae were measured. The mean lateral mass screw length was 13.2 mm (standard deviation [SD] 1.6 mm), mean outer pedicle width was 5.9 mm (SD 1.0 mm) and mean pedicle screw trajectory was 29.4 degrees (SD 3.6 degrees). Most (91.0%) of the pedicles had an outer diameter ≥4.5 mm. Conclusions The mean lateral mass screw length was longer when compared with other similar studies, while the mean outer pedicle width was narrower. Nearly 10% of the pedicles were unable to accommodate 3.5 mm screws. These findings favor the use of lateral mass screws to provide a safe and stable fixation for C7 vertebrae in Southern Chinese patients, while the final choice of fixation method should only be confirmed after careful preoperative planning with CT scan. PMID:27559451

  3. Biomechanical and morphometric evaluation of occipital condyle for occipitocervical segmental fixation

    International Nuclear Information System (INIS)

    Two recent novel techniques of occipital fixation are the occipitoatlantal (C0-C1) transarticular screw technique and the direct occipital condyle screw technique. The present study evaluated and compared the biomechanical stability of the direct occipital condyle screw and C0-C1 transarticular screw with the established method for craniocervical spine fixation using the midline occipital keel screw and C1 lateral mass screw. Morphometric evaluation of the occipital condyle and the hypoglossal canal was performed to avoid hypoglossal nerve injury during the screw placement. Thirteen recently frozen cadaveric specimens were used. The occipital condyle anatomy and the hypoglossal canal dimension were measured using reconstructed computed tomography images. Insertion torque and pullout strength were evaluated to compare the midline occipital keel screw, C0-C1 transarticular screw, C1 lateral mass screw, and direct occipital condyle screw. The dimensions of the occipital condyle allow use of a 3.5 or 4.0-mm diameter screw. Mean pullout strength was 1619.6 N for the midline occipital keel screw, 870.7 N for the C0-C1 transarticular screw, 707.0 N for the C1 lateral mass screw, and 431.7 N for the direct occipital condyle screw. Mean insertion torque was 0.55 Nm for the midline occipital keel screw, 0.32 Nm for the C0-C1 transarticular screw, 0.14 Nm for the C1 lateral mass screw, and 0.11 Nm for the direct occipital condyle screw. The condylar anatomy allows direct insertion of the occipital condyle screw and C0-C1 transarticular screw. These techniques are suitable options for the treatment of craniovertebral junction instabilities in selected patients. (author)

  4. Femoral neck shortening after internal fixation

    OpenAIRE

    LIU, YUE; AI, Zi Sheng; Shao, Jin; Yang, Tieyi

    2014-01-01

    Objective: The aim of this study was to assess the factors affecting femoral neck shortening after internal fixation of femoral neck fractures. Methods: Eighty-six patients with femoral neck fractures were treated using three parallel cannulated screws between May 2004 and January 2011. The shortening of the femoral neck in the horizontal (X), vertical (Y), and along the resultant along the (Z) vector (XÆ, YÆ, ZÆ) was measured on anteroposterior radiographs corrected by screw diameter and ...

  5. Design considerations for developing biodegradable and bioabsorbable magnesium implants

    Science.gov (United States)

    Brar, Harpreet S.; Keselowsky, Benjamin G.; Sarntinoranont, Malisa; Manuel, Michele V.

    2011-04-01

    The integration of biodegradable and bioabsorbable magnesium implants into the human body is a complex undertaking that faces major challenges. Candidate biomaterials must meet both engineering and physiological requirements to ensure the desired properties. Historically, efforts have been focused on the behavior of commercial magnesium alloys in biological environments and their resultant effect on cell-mediated processes. Developing causal relationships between alloy chemistry and microstructure, and effects as a cellular behavior can be a difficult and time-intensive process. A systems design approach has the power to provide significant contributions in the development of the next generation of magnesium alloy implants with controlled degradability, biocompatibility, and optimized mechanical properties, at reduced time and cost. This approach couples experimental research with theory and mechanistic modeling for the accelerated development of materials. The aim of this article is to enumerate this strategy, design considerations, and hurdles for developing new cast magnesium alloys for use as biodegradable implant materials.

  6. CT-guided fixation of sacral fractures and sacrolilac joint disruptions

    International Nuclear Information System (INIS)

    Placement of sacral fixation screws at surgery is performed blindly (ie, by palpation). The authors of this paper employed CT to localize the screw between the neutral foramina and anterior sacral cortex and to decrease the morbidity associated with general anesthesia and surgery. Six patients underwent CT-guided sacral fixation performed by means of the 7.0 mm A0 cannulated screw system. All patients had reducible vertical sacral fractures or sacroiliac joint disruptions. Following placement of an epidural catheter for anesthesia, patients were scanned in the prone or decubitus position. Measurements for placement of the guide pin were made from the preliminary scans. Following CT confirmation of satisfactory guide pin placement across the fracture, the screw track was drilled, the screw length was determined, and the fixation screw was placed in position. A CT scan was obtained to evaluate the final position of the screw

  7. 经伤椎置钉治疗胸腰椎骨折的临床运用及疗效分析%Posterior pedicle screw fixation at injured level for treatment of thoracolumbar spine fracture: analysis of clinical application and curative effect

    Institute of Scientific and Technical Information of China (English)

    袁志峰; 邵斌; 曾景平

    2013-01-01

    目的 探讨运用经伤椎置钉治疗胸腰椎骨折的效果.方法 2008年6月~2011年12月,50例胸腰椎骨折患者分别采用传统伤椎上下邻椎置钉(A组)及上下邻椎置钉加经伤椎置钉(B组)治疗,每组25例.以切口长度、手术时间、术中出血量、术前与术后伤椎椎体高度、术前与术后的侧位Cobb角、腰背部疼痛发生情况、内固定失败率等方面对比2组治疗效果.结果 切口长度、手术时间、术中出血量2组差异无统计学意义(P>0.05).2组患者术前、术后1周、术后6个月在椎体高度及Cobb角方面差异无统计学意义(P>0.05);在术后12个月及内固定取出后上述2项评价指标差异有显著的统计学意义(P<0.05).结论 经伤椎置钉治疗胸腰椎骨折术后椎体高度保持良好,腰背痛发生率低,切口长度、术中出血及手术时间无明显增加,是一种安全可靠、切实有效的治疗方法.%Objective To investigate the curative effect of posterior pedicle screw fixation at the injured level for the treatment of thoracolumbar spine fractures. Methods From June 2008 to December 2011 , a total of 50 patients with thoracolumbar spine fractures were equally randomized to Group A( treated with classic pedicle screw fixation ) and Group B( treated with pedicle screw fixation at the injured level )based on fixation methods( n = 25 ). The incision length, operation time, amount of bleeding in operation, preoperative and postoperative fractured vertebral body height, segmental lordosis ( Cobb' s angle ), visual analogue scale ( VAS ) score of lumbar pain and failure rate of internal fixation were assessed and compared clinically. Results There were no statistical significance in incision length, operation time and amount of bleeding( P >0. 05 ). Also, there were no statistical significance in fractured vertebral body height and Cobb' s angle at pre-operation, postoperative 1 week and postoperative 6 months( P >0. 05 ), But it had

  8. 特发性脊柱侧弯后路钉棒置入内固定:谁是影响效果的因素?%Posterior screw-rod fixation for idiopathic scoliosis:factors affecting the results

    Institute of Scientific and Technical Information of China (English)

    毕中普; 夏磊; 徐静磊; 周亚旗; 柯广水; 桑亮

    2014-01-01

    背景:特发性脊柱侧弯在脊柱侧弯中最常见,有时还伴有神经、内分泌系统以及营养代谢的异常,但保守治疗效果欠佳,通常需要进行手术治疗。畸形矫正是一个极其复杂的过程,对特发性脊柱侧弯治疗、转归等进行深入研究意义巨大,但目前缺少相近研究。  目的:观察后路钉棒内固定置入治疗特发性脊柱侧弯的矫正效果,探讨影响其效果的相关因素。  方法:回顾性分析近4年80例接受后路钉棒内固定置入治疗的特发性脊柱侧弯患者的病例资料,记录研究患者年龄、性别、病程、治疗前后X射线平片测量的冠状面Cobb's角、躯干偏移度等观察指标,并进行统计学分析。  结果与结论:单因素分析显示患者性别和患者病程均与内固定后矫正效果无明显相关(P>0.05);而患者年龄分布、侧凸的位置、侧凸的柔韧性均与内固定疗效相关(P OBJECTIVE:To observe the correction effect of posterior screw-rod fixation for idiopathic scoliosis, and explore the relevant factors influencing its effectiveness. METHODS:We retrospectively analyzed 80 cases receiving pedicle screw fixation in the treatment of idiopathic scoliosis in the latest four years. Age, gender, disease duration, preoperative and postoperative X-ray measurement of coronal Cobb’s angle, and trunk deviation were recorded, and statistical y analyzed. RESULTS AND CONCLUSION:Univariate analysis showed that gender and disease duration were not significantly correlated with postoperative correction results (P>0.05). However, the age distribution of patients, the location of scoliosis, and scoliosis flexibility were associated with curative effects of internal fixation (P<0.05). Posterior screw-rod fixation for idiopathic scoliosis can achieve significant effects. The patient’s age, location and flexibility of scoliosis have a significant effect on the effects of fixation. The

  9. A new concept for implant fixation: bone-to-bone biologic fixation.

    Science.gov (United States)

    Kim, D-Y; Kim, J-R; Jang, K Y; Lee, K-B

    2015-01-01

    Many attempts have been made to reduce complications of bone implant, such as pedicle screw loosening. To address this problem, the authors suggest a new concept of bone-to-bone biologic fixation using recombinant human bone morphogenetic protein-2 (rhBMP-2)-loaded cannulated pedicle screws. Recombinant human bone morphogenetic protein-2 is an osteoinductive cytokine. Four types of titanium pedicle screws were tested (uncannulated, cannulated with no loading, beta-tricalcium phosphate (TCP)-loaded, and TCP/BMP2 loaded) using 16 miniature pigs. Radiological evaluation was conducted to assess the fusion and loosening of pedicle screws. Twelve weeks after implantation, peak torsional extraction torque was measured, and the pedicle screw and bone interface was evaluated by micro-computed tomography (µCT) and histologic examination. The mean value of the radiological score was significantly greater in the TCP/BMP2 loaded group at 12 weeks post-operation compared to those in the other groups. CT images showed distinct bone formation surrounding TCP/BMP2 loaded cannulated pedicle screws compared to the other groups. Mean extraction torsional peak torque at 12 weeks postoperative was more than 10-fold higher in the TCP/BMP2 loaded pedicle screw group than in the other groups. Bone surface and bone volume, as quantitated through µCT, were higher in the TCP/BMP2 loaded group. Histologic examination revealed bone-to-bone fixation at the interface of pedicle screws and pre-existing bone. Bone-to-bone biologic fixation through the holes of TCP/BMP2 loaded pedicle screws significantly increased fixation strength and represents a novel method that can be applied to osteoporotic or tumour spine surgeries. PMID:25978116

  10. A new concept for implant fixation: bone-to-bone biologic fixation

    Directory of Open Access Journals (Sweden)

    D-Y Kim

    2015-05-01

    Full Text Available Many attempts have been made to reduce complications of bone implant, such as pedicle screw loosening. To address this problem, the authors suggest a new concept of bone-to-bone biologic fixation using recombinant human bone morphogenetic protein-2 (rhBMP-2-loaded cannulated pedicle screws. Recombinant human bone morphogenetic protein-2 is an osteoinductive cytokine. Four types of titanium pedicle screws were tested (uncannulated, cannulated with no loading, beta-tricalcium phosphate (TCP-loaded, and TCP/BMP2 loaded using 16 miniature pigs. Radiological evaluation was conducted to assess the fusion and loosening of pedicle screws. Twelve weeks after implantation, peak torsional extraction torque was measured, and the pedicle screw and bone interface was evaluated by micro-computed tomography (µCT and histologic examination. The mean value of the radiological score was significantly greater in the TCP/BMP2 loaded group at 12 weeks post-operation compared to those in the other groups. CT images showed distinct bone formation surrounding TCP/BMP2 loaded cannulated pedicle screws compared to the other groups. Mean extraction torsional peak torque at 12 weeks postoperative was more than 10-fold higher in the TCP/BMP2 loaded pedicle screw group than in the other groups. Bone surface and bone volume, as quantitated through µCT, were higher in the TCP/BMP2 loaded group. Histologic examination revealed bone-to-bone fixation at the interface of pedicle screws and pre-existing bone. Bone-to-bone biologic fixation through the holes of TCP/BMP2 loaded pedicle screws significantly increased fixation strength and represents a novel method that can be applied to osteoporotic or tumour spine surgeries.

  11. Strain-stress analysis of lower limb with applied fixator

    Directory of Open Access Journals (Sweden)

    Mrázek M.

    2010-07-01

    Full Text Available This paper compares physiological state of tibia before and after application of an external fixator. The fixator systems’ models but also model of tibia are loaded in the direction of body axis. The paper is focused on the examination of differences in stiffness before and after the application of fixation. Two types of axial external fixators are compared. Both fixators differ in their construction. The first fixator is two-frame and fixation rods are used for fixing the bone tissue (variant I. The second one is fixed into tibia with screws (variant II. We have found out that the two-frame external fixator has much bigger stiffness during limb fixation than the fixator with one body. Much higher deformations compared to physiological state of tibia occur in the variant II.

  12. Evaluation the treatment outcomes of intracapsular femoral neck fractures with closed or open reduction and internal fixation by screw in 18-50-year-old patients in Isfahan from Nov 2010 to Nov 2011

    Directory of Open Access Journals (Sweden)

    Mohammad Javdan

    2013-01-01

    Conclusion: This study showed that femoral neck fracture is associated with several complications, especially if open reduction was necessary. So, the surgical method and necessary equipments such as radiolucent bed, C-ARM machine, and implant cannulated screw set should be considered.

  13. Osteosynthesis-screw augmentation by ultrasound-activated biopolymer - an ovine in vivo study assessing biocompatibility and bone-to-implant contact

    OpenAIRE

    Neumann, Hanjo; Breer, Stefan; Reimers, Nils; Kasch, Richard; Schulz, Arndt-Peter; Kienast, Benjamin

    2015-01-01

    Objectives Screw fixation and fragment anchoring in osteoporotic bones is often difficult. Problems like the cut out phenomenon and implant migration in osteoporotic bones have been reported. One possibility of improving the anchoring force of screws is augmentation of the screw. Cement-augmented screws in spinal surgery could exhibit a better anchoring in osteoporotic bones. Methods The purpose of this study was to examine the effect of screw augmentation using a resorbable polymer. Ultrasou...

  14. GSS pedicle screw fixation combined with two-stage bone cement perfusion for thoracolumbar fractures%GSS椎弓根螺钉内固定并二期伤椎骨水泥灌注治疗胸腰椎骨折

    Institute of Scientific and Technical Information of China (English)

    宋洁富; 李利军; 常峰; 荆志振

    2012-01-01

    Objective To explore the efficacy and safety of surgical treatment of thoracolumbar fractures by GSS pedicle screw fixation combined with two-stage bone cement perfusion. Methods From March 2005 to October 2010, 31 patients with thoracolumbar bursting fractures were treated with posterior GSS pedicle screw fixation. The patients were reviewed by X-ray and CT scan 3-18 months postoperatively. Once "eggshell phenomenon" appeared, bone cement was used in the injured vertebral body before removing the fixators. Injured vertebral height and Cobb' s angle were measured preoperatively, postoperatively and at the final follow-up. Results No leakage of bone cement happened in all the patients. The internal fixators were removed 12-18 months postoperatively. Then the patients were followed up for 1-3 years. Fractured vertebral height and Cobb' s angle were significantly improved after surgery. Conclusion GSS combined with two-stage bone cement perfusion for thoracolumbar fractures can achieve a good therapeutic effect. It can be taken as an attempt at the treatment of thoracolumbar fractures.%目的 探讨GSS椎弓根螺钉内固定结合二期伤椎骨水泥灌注治疗胸腰椎骨折的有效性和安全性.方法 2005年3月~2010年10月共31例胸腰椎爆裂性骨折患者行后路GSS椎弓根螺钉内固定治疗,术后3~18个月根据X线及CT复查情况,出现"蛋壳现象"的患者在取出内固定前行伤椎骨水泥灌注,记录术前、术后及末次随访时的伤椎高度及X线片测量的Cobb角角度.结果 本组患者均未出现骨水泥渗漏,术后12~18个月取出内固定后再随访1~3年.术后伤椎椎体高度及Cobb角与术前相比有明显改善.结论 GSS椎弓根螺钉内固定结合二期伤椎骨水泥灌注治疗胸腰椎骨折可达到良好的治疗效果,可作为治疗胸腰椎骨折的新的尝试.

  15. 聚甲基丙烯酸甲酯和自体骨加强的椎弓根螺钉技术治疗退变性脊柱侧凸的临床疗效比较%Autogenous bone and polymethylmethacrylate augmentation of screw fixation for degenerative scoliosis

    Institute of Scientific and Technical Information of China (English)

    谢杨; 傅强; 陈自强; 石志才; 朱晓东; 孙晓飞; 李明

    2012-01-01

    Objective To compare the clinical effect of autogenous bone and polymethylmethacrylate (PMMA) augmentation of screw fixation in degenerative scoliosis with osteoporosis. Methods A retrospective analysis was conducted on 31 consecutive patients with degenerative scoliosis combined with osteoporosis who accepted pedicle screw fixation from December 2000 to December 2006. Fourteen of them underwent fixation with pedicle screw by augmentation with PMMA and the other 17 patients with autogenous bone. Peri-operative data were recorded. Preoperative, postoperative and final follow up corrective effects were compared. Results No significant difference was found in clinical data except for administration time of oral pain relief medicines and surgery cost between the two surgical strategies. Cement leakage was observed in 2 patients in PMMA augmentation group, but there was no evidence of nerve damage. Conclusion There is no difference in surgical effect between two surgery strategies on degenerative scoliosis combined with osteoporosis. Less oral pain medicines are taken in the polymethylmethacrylate-augmented pedicle screw fixation and fusion, but with much more cost and danger of cement leakage.%目的 比较应用聚甲基丙烯酸甲酯( PMMA)和自体骨加强的椎弓根螺钉技术治疗合并骨质疏松的退变性脊柱侧凸的临床疗效.方法 回顾性分析2000年12月至2006年12月手术治疗的31例伴骨质疏松的退变性脊柱侧凸患者,其中14例采用PMMA加强钉道,17例采用自体骨加强钉道.记录并发症等围手术期情况,比较手术前后及随访期间侧凸的矫正效果.结果 两种手术除口服止痛药使用时间和手术费用外,其他临床数据差异无统计学意义,PMMA加强组中2例出现骨水泥渗漏,但未出现神经损伤的症状.结论 两种手术对伴骨质疏松的退变性脊柱侧凸的临床疗效无明显差异,PMMA加强的椎弓根螺钉内固定融合术可减少口服止痛药的用量,

  16. Correlation of pull-out strength of cement-augmented pedicle screws with CT-volumetric measurement of cement.

    OpenAIRE

    Fölsch, Christian; Goost, Hans; Figiel, Jens; Paletta, Jürgen R. J.; Schultz, Wolfgang; Lakemeier, Stefan

    2012-01-01

    BACKGROUND: Cement augmentation of pedicle screws increases fixation strength in an osteoporotic spine. This study was designed to determine the cement distribution and the correlation between the pull-out strength of the augmented screw and the cement volume within polyurethane (PU) foam. METHODS: Twenty-eight cannulated pedicle screws (6×45 mm) (Peter Brehm, Erlangen, Germany) with four holes at the distal end of the screw were augmented with the acrylic Stabilit ER Bone Cement Vertebr...

  17. 空心拉力螺钉加镍钛聚髌器置入内固定重建骨折髌骨的生物力学条件%Biomechanical requirement for the reconstruction of patellar fracture treated with cancellous bone screw and nickel-titanium-patellar concentrator internal fixation

    Institute of Scientific and Technical Information of China (English)

    高振巢; 刘德昌; 蔡国平

    2013-01-01

    BACKGROUND: There are various internal fixation methods for the clinical treatment of patel ar fractures, but each method has advantages and disadvantages, respectively. The selection of proper internal fixation method wil directly affect the healing time and recovery of knee joint function. OBJECTIVE: To investigate the biomechanical reconstruction effect on patel ar fracture treated with cancel ous bone screw and nickel-titanium-patel ar concentrator internal fixation. METHODS: A retrospective analysis was performed on 27 cases of acute patel ar fracture patients from January 2011 to January 2012 in the Department of Orthopedics, Jinshan Hospital, Fudan University, including 13 cases of transverse fracture, 11 cases of comminuted fracture and three cases of upper or lower pole fracture. Al the 27 patients received cancel ous bone screw and nickel-titanium-patel ar concentrator internal fixation without plaster external fixation, and then the quadriceps active contraction training was performed from the 2nd day after internal fixation, and bed knee flexion and extension exercises were performed at 1 week after internal fixation. The knee joint function was evaluated with Böstman score system. RESULTS AND CONCLUSION: Al the 27 patients were fol owed-up for 4-14 months. Incisions obtained stage Ⅰ healing, and there was no fracture fixation or shedding, wound infection, skin necrosis or other complications. The average healing time was 8.5 weeks without delayed healing. According to clinical grading scale of Böstman score system, the mean score was 27.9, included 27 cases of excel ent (81%), four cases of good (15%), one case of poor (4%), and the excel ent and good rate was 96%. The results suggest that cancel ous bone screw combined with nickel-titanium-patel ar concentrator internal fixation can maintain the advantages of traditional internal fixation method, and can avoid the disadvantages of the traditional internal fixation method.%  背景:目前

  18. A Review of Material Degradation Modelling for the Analysis and Design of Bioabsorbable Stents.

    Science.gov (United States)

    Boland, Enda L; Shine, Rosa; Kelly, Nicola; Sweeney, Caoimhe A; McHugh, Peter E

    2016-02-01

    The field of percutaneous coronary intervention has witnessed many progressions over the last few decades, more recently with the advancement of fully degradable bioabsorbable stents. Bioabsorbable materials, such as metallic alloys and aliphatic polyesters, have the potential to yield stents which provide temporary support to the blood vessel and allow native healing of the tissue to occur. Many chemical and physical reactions are reported to play a part in the degradation of such bioabsorbable materials, including, but not limited to, corrosion mechanisms for metals and the hydrolysis and crystallization of the backbone chains in polymers. In the design and analysis of bioabsorbable stents it is important to consider the effect of each aspect of the degradation on the material's in vivo performance. The development of robust computational modelling techniques which fully capture the degradation behaviour of these bioabsorbable materials is a key factor in the design of bioabsorable stents. A critical review of the current computational modelling techniques used in the design and analysis of these next generation devices is presented here, with the main accomplishments and limitations of each technique highlighted. PMID:26271520

  19. Computer-Assisted Percutaneous Scaphoid Fixation: Concepts and Evolution

    OpenAIRE

    Smith, Erin J.; Ellis, Randy E.; Pichora, David R.

    2013-01-01

    Background The treatment for undisplaced scaphoid waist fractures has evolved from conventional cast immobilization to percutaneous screw insertion. Percutaneous fixation reduces some of the risks of open surgery, but can be technically demanding and carries the risk of radiation exposure. Recently, computer-assisted percutaneous scaphoid fixation (CAPSF) has been gaining interest.

  20. Pedicle screw reduction and fixation combined with calcium sulfate cement vertebroplasty in the treatment of thoracolumbar fractures%椎弓根钉复位固定结合注射型硫酸钙椎体成形术治疗胸腰椎骨折

    Institute of Scientific and Technical Information of China (English)

    魏力今; 周业金; 刘艺明; 潘良春; 李春; 何高

    2011-01-01

    目的 总结椎弓根钉复位固定结合注射型硫酸钙(CSC) 椎体成形术治疗胸腰椎骨折的方法与疗效.方法 对23 例(25椎)胸腰椎骨折采用切开复位椎弓根钉固定,用特定注射器经伤椎椎弓根穿刺注入CSC进行椎体成形术治疗,影像学评估术前、术后及取钉12个月后矢状位指数(SI)及椎体前、后缘高度压缩率变化.结果 平均每个椎体注入CSC 5.34 ml,6例术中发生椎旁渗漏,无椎管内渗漏,术后患者神经功能Frankel分级较术前提高1~2级(P<0.05).术后8~12周影像学结果 提示,硫酸钙在椎体内完全消失,被正常骨组织吸收.术后及取钉12个月后SI角及椎体前、后缘高度压缩率均较术前有明显改善(P<0.01),术后至取钉12个月后椎体前缘无明显丢失,但椎体后缘有少量丢失(P<0.05).本组无椎弓根钉失败病例.结论 椎弓根钉复位固定结合CSC椎体成形术治疗胸腰椎骨折,能使复位后的伤椎恢复其完整形态及椎体强度,提高胸腰椎骨折的临床疗效,其方法简便、安全,近期疗效满意.%Objective To investigate the method and effect of pedicle screw reduction and fixation combined with calcium sulfate cement ( CSC ) vertebroplasty in the treatment of thoracolumbar fractures. Methods 23 cases ( 25 vertebrae ) with thoracolumbar fractures were treated with pedicle screw sagittal index( SI ) angle reduction and fixation combined with CSC vertebroplasty. According to imaging, we evaluated the change SI angle and compression ratio of vertebral body at the time of preoperation, postoperation and 12 months later. Results Each vertebra was injected with 5. 34 ml CSC on average. 6 cases got paravertebral leakage. No vertebral canal leakage was found.Frankel grading of neural function was improved. CSC disappeared in 8 ~12 weeks and substituted by bone. In the postoperative and 12 months films, the SI angle, vertebral height were improved ( P <0. 01 ). The anterior height did not

  1. Ball screw inspection setup

    Science.gov (United States)

    Janusz, Rzepka; Sambor, Slawomir; Pienkowski, Janusz; Bielenin, Marcin

    2003-05-01

    In the following paper we describe arrangements of laser interferometer for investigation of screws and for inspection of ball screws. We have constructed two of them, namely: the technological setup for investigations of screw in process of production and the ball screw inspection setup. The former one is used to measure the pitch of screws. The data gathered during measurement is used to calculate the parameters for grinding machine. The later setup is used for testing parameters of complete ball screws. The software supporting this setup makes calculation of parameters of tested ball screw and creation of reports possible. Additionally, the inspection setup is the one that the torque measuring arrangements have been integrated on. Both the arrangements and the software allow for measurements of all parameters during movement of nut in full travel length of the ball screw and make charts and reports.

  2. Effect of the bio-absorbent on the microwave absorption property of the flaky CIPs/rubber absorbers

    International Nuclear Information System (INIS)

    Microwave absorbing composites filled with flaky carbonyl iron particles (CIPs) and the bio-absorbent were prepared by using a two-roll mixer and a vulcanizing machine. The electromagnetic (EM) parameters were measured by a vector network analyzer and the reflection loss (RL) was measured by the arch method in the frequency range of 1–4 GHz. The uniform dispersion of the absorbents was verified by comparing the calculated RL with the measured one. The results confirm that as the bio-absorbent was added, the permittivity was increased due to the volume content of absorbents, and the permeability was enlarged owing to the volume content of CIPs and interactions between the two absorbents. The composite filled with bio-absorbents achieved an excellent absorption property at a thickness of 1 mm (minimum RL reaches −7.8 dB), and as the RL was less than −10 dB the absorption band was widest (2.1–3.8 GHz) at a thickness of 2 mm. Therefore, the bio-absorbent is a promising additive candidate on fabricating microwave absorbing composites with a thinner thickness and wider absorption band. - Graphical abstract: Morphology of composites filled with flaky CIPs and the bio-absorbent. The enhancement of bio-absorbent on the electromagnetic absorption property of composites filled with flaky carbonyl iron particles (CIPs) is attributed to the interaction of the two absorbents. The volume content of the FCMPs with the larger shape CIPs play an important role in this effects, the composites filled with irons and bio-absorbents can achieve wider-band and thinner-thickness absorbing materials. - Highlights: • Absorbers filled with bio-absorbents and CIPs was fabricated. • Bio-absorbents enhanced the permittivity and permeability of the composites. • The absorbent interactions play a key role in the enhancement mechanism. • Bio-absorbents enhanced the composite RL in 1–4 GHz

  3. Short-segment versus long-segment pedicle screw fixation for repair of thoracolumbar fracture:one-year follow-up of vertebral compression rate%短节段与长节段椎弓根螺钉置入修复胸腰椎骨折比较:椎体压缩率1年随访

    Institute of Scientific and Technical Information of China (English)

    苏伟坤; 叶少腾

    2015-01-01

    背景:后路减压内固定修复胸腰椎骨折效果肯定,又根据处理方法的不同分为短节段与长节段椎弓根螺钉内固定。目前临床上关于两种修复方案的疗效,存在较大争议。目的:对比观察经后路短节段与长节段椎弓根螺钉置入内固定修复胸腰椎骨折患者的伤椎前缘压缩率及Cobb角变化率。方法:纳入胸腰椎骨折患者120例,根据内固定方案分为两组,研究组采用经后路短节段椎弓根螺钉内固定,对照组采用经后路长节段椎弓根螺钉内固定。观察两组患者内固定前、内固定后即刻、内固定后12个月伤椎前缘压缩率以及Cobb角变化率。结果与结论:内固定前两组患者伤椎前缘压缩率、Cobb角变化率差异均无显著性意义(P >0.05)。内固定后即刻及内固定后12个月,可见研究组伤椎前缘压缩率、Cobb角变化率均明显小于对照组,差异均有显著性意义(P 0.05). Anterior vertebral compression rate and Cobb angle were significantly smal er in the study group than in the control group immediately and 12 months after fixation (P<0.05). Besides, surgical time and blood loss volume were less in the study group than in the control group (P<0.05). These results indicated that posterior short-segment pedicle screw fixation for treatment of thoracolumbar fracture can effectively improve kyphosis, recover vertebral compression degree, and its surgical time is short and blood loss volume during surgery is little, so it is better than posterior long-segment pedicle screw fixation.

  4. 单侧椎弓根螺钉内固定联合单枚融合器治疗极外侧腰椎间盘突出症%Unilateral pedicle screw fixation combined with single cage interbody fusion for far lateral lumbar disc herniation

    Institute of Scientific and Technical Information of China (English)

    王佳; 周耀; 李伟; 杨方

    2013-01-01

    Objective To evaluate the surgical results of treating far lateral lumbar disc herniations by lumbar inter-body fusion with unilateral pedicle screw fixation and single cage. Methods 26 cases of far lateral lumbar disc herniations were received the treatment of lumbar interbody fusion with unilateral pedicle screw fixation and single cage via a posterior approach. X-ray or CT examinations were taken in the regular follow-up to observe the fusion rates and complications, and the outcome of the surgery was assessed by Japanese Orthopaedic Association ( JOA ) low back pain scores. Results There were no wound infection or nerve complications after operation. All patients were followed up for 18 ~27 months. The fusion rate was 96. 2%( 25/26 ). The average JOA scores of preoperation and final followed-up were 12. 43 2. 16 and 24. 53 2. 97 respectively, which showed significant difference ( P <0. 05 ) between the two observations. The mean improvement rate was 81. 6% , and 19 cases got excellent results,5 good and 2 fair. The excellent and good rate was 92. 3%( 24/26 ). Conclusions Lumbar interbody fusion with unilateral pedicle screw fixation combined with single cage can provide simple procedure, little trauma, reliable fixation, high fusion rate, and satisfactory clinical results.%目的 评估单侧椎弓根螺钉内固定联合单枚融合器治疗极外侧腰椎间盘突出症的疗效.方法 对26例极外侧腰椎间盘突出症患者经腰椎后路行单侧椎弓根螺钉内固定联合单枚cage的融合手术.术后定期复查X线片或CT片,观察融合率及并发症情况;采用JOA腰腿痛评分法评估疗效.结果 术后均无伤口感染、神经损伤.患者均获随访,时间18~27个月.临床融合率96.2%(25/26).JOA评分:术前为12.43分±2.16分,末次随访时为24.53分±2.97分,差异有统计学意义(P<0.05),平均改善率为81.6%.疗效评定:优19例,良5例,中2例,优良率92.3%(24/26).结论 单侧椎弓根螺钉内固定联合单

  5. Decompressive cervical laminectomy and lateral mass screw-rod arthrodesis. Surgical analysis and outcome

    OpenAIRE

    Obaidat Mouness H; Dabbas Waleed F; Qudsieh Tareq M; Obeidat Moutasem M; Audat Ziad A; Al Barbarawi Moh'd M; Malkawi Anas A

    2011-01-01

    Abstract Background This study evaluates the outcome and complications of decompressive cervical Laminectomy and lateral mass screw fixation in 110 cases treated for variable cervical spine pathologies that included; degenerative disease, trauma, neoplasms, metabolic-inflammatory disorders and congenital anomalies. Methods A retrospective review of total 785 lateral mass screws were placed in patients ages 16-68 years (40 females and 70 males). All cases were performed with a polyaxial screw-...

  6. 腓骨远端解剖型钢板与空心螺钉置入内固定修复Danis-Weber B型双踝骨折%The distal fibula anatomic plate combined with hollow screw fixation for Danis-Weber B double ankle fractures

    Institute of Scientific and Technical Information of China (English)

    马运宏

    2015-01-01

    背景:踝关节骨折是临床上常见的骨折,Danis-Weber B型骨折所占比例较大,对外踝的解剖复位以及选择适合的内固定物是修复成败的关键。  目的:观察解剖型钢板和空心螺钉联合内固定修复踝关节内外侧面骨折的解剖复位效果。  方法:对2010年3月至2013年10月收治的32例Danis-Weber B型踝关节骨折患者进行回顾性研究,内固定方式外踝均选用钢板螺钉固定,内踝骨块均选用双螺纹加压螺钉固定。采用美国足踝外科协会(AOFAS)的踝与后足评分系统及Kofoed踝关节评分对患者踝关节功能进行评估,以目测类比评分评定修复后疼痛程度的改善,根据影像学结果分析内固定后对线对位的生物力学水平。  结果与结论:所有患者均获得6-24个月随访,所有病例均骨性愈合。治疗后随访6个月患者踝关节AOFAS评分、Kofoed评分及目测类比评分均显著优于治疗前,差异有显著性意义(P <0.05)。影像学结果显示,内固定后对线对位良好。有1例感染患者,其他无不良反应。提示应用解剖型钢板和空心螺钉置入内固定修复踝关节内、外踝双踝骨折,可发挥解剖钢板与空心螺钉各自的特点及生物力学优势,使骨折达到踝关节的解剖复位。%BACKGROUND:Ankle joint fracture is a common fracture in the clinic. Proportion of Danis-Weber B fracture was large. Anatomic reduction and suitable internal fixator of lateral mal eolus are the key for successful repair. OBJECTIVE:To analyze the anatomic reduction effect of anatomic plate combined with hol ow screw fixation for inner and outer side fracture of the ankle joint. METHODS:A total of 32 patients with Danis-Weber B ankle fracture, who were treated from March 2010 to October 2013, were retrospectively analyzed. Plate and screw were used for internal fixation of lateral mal eolus. Double thread compression screw was used for fixation

  7. Absorbable scaphoid screw development: a comparative study on biomechanics

    OpenAIRE

    Xu, Yongqing

    2016-01-01

    Yi Wang, Muguo Song, Yongqing Xu, Xiaoqing He, YueLiang Zhu Department of Orthopedic Surgery, Kunming General Hospital, Chengdu Military Command, People’s Liberation Army, Kunming, Yunnan, People’s Republic of China Background: The scaphoid is critical for maintaining the stability and movement of the wrist joints. This study aimed to develop a new internal fixator absorbable scaphoid screw (ASS) for fixation of the scaphoid waist after fracture and to test the biomechan...

  8. Absorbable scaphoid screw development: a comparative study on biomechanics

    OpenAIRE

    Wang Y; Song MG; Xu YQ; He XQ; Zhu YL

    2016-01-01

    Yi Wang, Muguo Song, Yongqing Xu, Xiaoqing He, YueLiang Zhu Department of Orthopedic Surgery, Kunming General Hospital, Chengdu Military Command, People’s Liberation Army, Kunming, Yunnan, People’s Republic of China Background: The scaphoid is critical for maintaining the stability and movement of the wrist joints. This study aimed to develop a new internal fixator absorbable scaphoid screw (ASS) for fixation of the scaphoid waist after fracture and to test the biomechanical cha...

  9. Absorbable scaphoid screw development: a comparative study on biomechanics

    OpenAIRE

    Wang, Yi; Song, Muguo; Xu, Yongqing; He, Xiaoqing; Zhu, Yueliang

    2016-01-01

    Background The scaphoid is critical for maintaining the stability and movement of the wrist joints. This study aimed to develop a new internal fixator absorbable scaphoid screw (ASS) for fixation of the scaphoid waist after fracture and to test the biomechanical characteristics of ASS. Materials and methods An ASS was prepared using polylactic acids and designed based on scaphoid measurements and anatomic features. Twenty fractured scaphoid waist specimens were randomly divided into experimen...

  10. Biomechanical analysis of lumbosacral fixation.

    Science.gov (United States)

    McCord, D H; Cunningham, B W; Shono, Y; Myers, J J; McAfee, P C

    1992-08-01

    Flexion testing was performed until failure on 66 lumbosacral bovine spinal segments comparing ten different lumbosacral instrumentation techniques. Maximum flexion moment at failure, flexural stiffness, and maximum angulation of the lumbosacral joint at failure were determined as well as strain measurements across the anterior aspect of the lumbosacral intervertebral disc using an extensometer. The maximum moment at failure was significantly greater for the only two devices that extended fixation into the ilium anterior to the projected image of the middle osteoligamentous column: ISOLA Galveston and ISOLA iliac screws (F = 12.2, P less than 0.001). The maximum stiffness at failure reinforced these findings (F = 23.7, P less than 0.001). A second subset of stability showed the advantages of S2 pedicle fixation by increasing the flexural lever arm (Cotrel-Dubousset butterfly plate, and Cotrel-Dubousset Chopin block, P less than 0.05). This exhaustive in vitro biomechanical study introduces the concept of a pivot point at the lumbosacral joint at the intersection of the middle osteoligamentous column (sagittal plane) and the lumbosacral intervertebral disc (transverse plane). A spinal surgeon can increase the stability of lumbosacral instrumentation by extending fixation through the anterior sacral cortex (Steffee plate group with pedicle screws that medially converge in a triangular fashion). A means of enhancing this fixation was to achieve more inferior purchase by extending the fixation down to the S2 pedicle (Cotrel-Dubousset Chopin and Cotrel-Dubousset butterfly groups). However, the best fixation was achieved by obtaining purchase between the iliac cortices down into the superior acetabular bone.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1523506

  11. Biomechanical analysis on transverse tibial fixation in anterior cruciate ligament reconstructions

    Directory of Open Access Journals (Sweden)

    Edmar Stieven Filho

    2015-04-01

    Full Text Available OBJECTIVE: To verify whether the combination of tibial cross pin fixation and femoral screw fixation presents biomechanical advantages when compared to femoral cross pin fixation and tibial screw fixation for the reconstruction of the anterior cruciate ligament (ACL.METHODS: Thirty-eight porcine knees and bovine extensor digitorum tendons were used as the graft materials. The tests were performed in three groups: (1 standard, used fourteen knees, and the grafts were fixated with the combination of femoral cross pin and a tibial screw; (2 inverted, used fourteen knees with an inverted combination of tibial cross pin and a femoral screw; (3 control, ten control tests performed with intact ACL. After the grafts fixation, all the knees were subjected to tensile testing to determine yield strength and ultimate strength.RESULTS: There was no statistically significant difference in survival techniques in regard to strength, yield load and tension. There was a higher survival compared in the standard curves of yield stress (p < 0.05.CONCLUSION: There is no biomechanical advantage, observed in animal models testing, in the combination of tibial cross pin fixation and femoral screw when compared to femoral cross pin fixation and tibial screw.

  12. Biomechanical analysis on transverse tibial fixation in anterior cruciate ligament reconstructions☆

    Science.gov (United States)

    Filho, Edmar Stieven; Mendes, Mariane Henseler Damaceno; Claudino, Stephanie; Baracho, Filipe; Borges, Paulo César; da Cunha, Luiz Antonio Munhoz

    2015-01-01

    Objective To verify whether the combination of tibial cross pin fixation and femoral screw fixation presents biomechanical advantages when compared to femoral cross pin fixation and tibial screw fixation for the reconstruction of the anterior cruciate ligament (ACL). Methods Thirty-eight porcine knees and bovine extensor digitorum tendons were used as the graft materials. The tests were performed in three groups: (1) standard, used fourteen knees, and the grafts were fixated with the combination of femoral cross pin and a tibial screw; (2) inverted, used fourteen knees with an inverted combination of tibial cross pin and a femoral screw; (3) control, ten control tests performed with intact ACL. After the grafts fixation, all the knees were subjected to tensile testing to determine yield strength and ultimate strength. Results There was no statistically significant difference in survival techniques in regard to strength, yield load and tension. There was a higher survival compared in the standard curves of yield stress (p < 0.05). Conclusion There is no biomechanical advantage, observed in animal models testing, in the combination of tibial cross pin fixation and femoral screw when compared to femoral cross pin fixation and tibial screw. PMID:26229913

  13. 单侧椎弓根钉固定结合单枚融合器治疗腰椎不稳症%Treatment of lumbar instability with transforaminal lumbar interbody fusion (with single cage) combined with uni-lateral pedicle screw fixation

    Institute of Scientific and Technical Information of China (English)

    华永均; 王人彦; 郭志辉; 朱利民; 陆建阳

    2014-01-01

    Objective:To explore the clinical effect of transforaminal lumbar interbody fusion (with single cage) combined with unilateral pedicle screw fixation in treating lumbar instability. Methods:The clinical data of 50 patients with lumbar in-stability were retrospectively analyzed. They underwent treatment and obtained following up more than 8 months from 2009 to 2012. All patients complicated with refractory or recurrent lower back pain ,and unilateral primarily or unilateral lower limb ra-diation pain,X ray and CT films showed lumbar instability. The patients were respectively treated with transforaminal lumbar interbody fusion (with single cage) combined with unilateral or bilateral pedicle screw fixation. According to different fixation methods,they divided into unilateral fixation group and bilateral fixation group. There were 20 patients with 22 intervertebral spaces in unilateral fixation group,8 males and 12 females,aged from 26 to 66 years old,2 cases with isthmic spondylolisthesis of degreeⅠ,8 cases with degenerative spondylolisthesis,10 cases with lumbar disc herniation;fusion location with L3,4 was in 1 case,L4,5 was in 12 cases,L5S1 was in 9 cases. There were 30 patients with 30 intervertebral spaces in bilateral fixation group,14 males and 16 females,aged from 41 to 62 years old,4 cases with isthmic spondylolisthesis of degree Ⅰ,14 cases with degenerative spondylolisthesis,12 cases with lumbar disc herniation;fusion location with L3,4 was in 3 cases,L4,5 was in 15 case,L5S1 was in 12 cases. Operation time,intraoperative blood loss,postoperative drainage,complications were analyzed and intervertebral height,lordosis angle changes,fusion rate and clinical effect were compared between two groups. Results:All incisions obtained primary healing,lower limb radiation pain and low back pain disappeared basically,no infection,endo-rachis injury was found. Foot drop occurred in one case of bilateral fixation group and no iatrogenic neurological symptom was

  14. Omni - posterior decompression and transpedicular screw fixation in thoracic spine for thoracic ossification of ligamentum flavum%后路全椎板减压+胸椎弓根钉内固定术治疗胸椎黄韧带骨化的疗效分析

    Institute of Scientific and Technical Information of China (English)

    施清选; 叶志明; 林文武; 朱志侠

    2011-01-01

    Objective To examine the clinical efficacy of omni - posterior decompression and transpedicular screw fixation in thoracic spine in the treatment of thoracic ossification of ligamentum flavum.Methods The clinical data of 27 patients with thoracic ossification of flavum who underwent omni -posterior decompression and transpedicular screw fixation in thoracic spine in our hospital from January 2002 to January 2008 were retrospectively analyzed.The patients included 18 males and 9 females at age of 47 to 71 years with an average of 58 years.All of them were given routine X - ray,CT and MRI examinations preoperatively.The improved Macnab standard and VAS scoring system were used to evaluate the surgical effects.Results According to the Macnab standard,the excellent and good rate was 77.8% in this cohort within one year after operation and the effective rate was 85.1%.The excellent and good rate reached 85.1% one year after operation.VAS scoring revealed that the satisfactory degree was 66.6%within a year and 75% a year later.The mean follow - up duration was 2.5 year( 1.5 to 5 years).Conclusion Omni - posterior decompression and transpedicular screw fixation in thoracic spine is a safe and effective operation method for thoracic ossification of ligamentum flavum.%目的 探讨后路全椎板减压+胸椎弓根钉内固定术治疗胸椎黄韧带骨化的疗效.方法 回顾性总结2002年至2008年间胸椎黄韧带骨化病例27例.患者术前均常规给予X线、CT及MRI检查.手术采用后路全椎板减压+椎弓根钉内固定术.术后采用改良Macnab疗效评定标准及VAS评分,评价治疗效果.结果 术后改良Macnab疗效评定标准,27例患者术后1年内优良率77.8%,手术总有效率85.2%,1年后优良率85.1%.VAS评分应用专用评分尺,患者总满意度为66.6%,1年后总满意度为75%.结论 后路全椎板减压+胸椎弓根钉内固定术为治疗胸椎黄韧带骨化安全有效的手术方式.

  15. 骨水泥强化椎弓根钉固定联合椎体成形术治疗重度骨质疏松性脊柱骨折%Pedicle screw fixation strengthened with bone cement combined with vertebroplasty for the treatment of severe osteoporotic fractures

    Institute of Scientific and Technical Information of China (English)

    胡明; 李大伟; 黄凤山; 刘玉川; 杨达宇; 马远征

    2011-01-01

    Objective To explore the peri-operative treatment and clinical efficacy of pedicle screw fixation strengthened with bone cement combined with vertebroplasty for the treatment of severe osteoporotic fractures. Methods The clinical data of 15 patients with severe vertebral osteoporotic compression fractures were retrospectively analyzed from August 2005 to April 2009. The average age of the patients was 63. 1 years old. They had no severe basal diseases. They were all treated with posterior pedicle screw fixation strengthened with bone cement combined with vertebroplasty. All patients were followed up for 10-38 months (21 months in average) after the operation. Results All patients could tolerate the surgery and the average operating time was 106. 7 ±5. 3 min. The average bleeding volume was 370 ± 6. 1 ml. The twist and back pain were significantly ameliorated after the surgery. The height of vertebral body recovered back to 90% after operation. The height loss was not obvious during the following up. Conclusion The efficacy of pedicle screw fixation strengthened with bone cement combined with vertebroplasty for the treatment of severe osteoporotic fractures is good at correcting fracture and maintaining the recovering effect of the vertebra. The key point of this therapy is the surgical indication and osteoporotic medicine treatment.%目的 探讨骨水泥强化椎弓根钉固定联合椎体成形术治疗严重骨质疏松性椎体压缩骨折的围术期处理和临床疗效.方法 回顾分析2005年8月~ 2009年4月收治的15例严重骨质疏松性椎体压缩骨折患者的临床资料,平均63.1岁,无重大基础病存在,经脊柱后入路椎弓根钉撑开复位,钉道采用骨水泥灌注加强并行经伤椎椎体成形术.术后随访10~ 38个月,平均21月.结果 均耐受手术,平均手术时间为106.7±5.3min;平均失血量为370±6.1ml,术后腰背痛明显改善,椎体高度恢复至90%左右,随访椎体高度

  16. 单双侧椎弓根钉内固定结合椎间融合术治疗腰椎椎间盘突出症初期疗效比较%Early clinical effects of internal fixation with unilateral versus bilateral transpedicle screws combined with intervtebral fusion in lumbar disc herniation

    Institute of Scientific and Technical Information of China (English)

    夏才伟; 王生介; 厉晓龙; 刘伟峰; 刘俊; 杨雷; 蒋小军

    2011-01-01

    Objective To compare the early clinical effects of internal fixation with unilateral versus bilateral transpedicle screws combined with intervertebral fusion in lumbar disc herniation. Methods From March 2008 to June 2009, 40 patients with L4/L5 disc herniation were treated by internal fixation with unilateral ( n = 16 ) or bilateral ( n = 24) transpedicle screws combined with intervertebral fusion. The pre- and postoperative data of patients were compared between the 2 techniques, such as visual analog scale (VAS) and Oswestry disability index (ODI) scores, operation time, blood loss, hospital days, cost of hospitalization, fusion rate and incidence rate of complications. Results The differences of the preoperative VAS and ODI scores between patients with different operation had no statistic significance ( P > 0. 05 ), and neither had the differences of VAS and ODI scores, fusion rate, and incidence rate of complications at the last follow-up (P>0. 05). The postoperative data of all patients were better than those before surgery. The operation time, blood loss and cost of hospitalization of patients with unilateral instruments were better than those of patients with bilateral instruments. Conclusion The internal fixation with unilateral transpedicle screws combined with intervertebral fusion is as effective as with bilateral instruments in L4/L5 disc herniation, which is lower cost, less operation time and blood loss during the operation.%目的 探讨单侧椎弓根钉内固定结合椎间融合术治疗L4/L5椎间盘突出症的初期临床疗效及优势.方法 2008年3月~2009年6月行内固定椎体间融合术治疗L4/L5椎间盘突出症患者40例,其中单侧内固定16例,平均随访22.1个月;双侧内固定24例,平均随访20.8个月.比较2种手术患者术前疼痛视觉模拟量表(visual analog scale,VAS)和Oswestry功能障碍指数(Oswestry disability index,ODI)评分、手术时间、术中出血量、术后住院天数、住院费用

  17. Fixação de fraturas ilíacas em cães com parafusos, fios de aço e cimento ósseo de polimetilmetacrilato Canine iliac fracture fixation with screws, orthopedic wire and polymethylmethacrylate bone cement

    Directory of Open Access Journals (Sweden)

    Claudio Roehsig

    2008-09-01

    Full Text Available O presente trabalho teve como objetivo verificar a recuperação da locomoção e o tempo para cicatrização óssea de fraturas ilíacas fixadas com parafusos, fios de aço e cimento ósseo de polimetilmetacrilato. Dezesseis cães de ambos os sexos, com peso de 1,8 a 16kg e idade entre sete meses e 11 anos, foram submetidos à osteossíntese da fratura de ílio, provocadas por acidente automobilístico. Em dois animais, realizou-se osteossíntese bilateral, totalizando 18 ossos ilíacos operados. A abordagem ao ílio foi lateral e quando necessária estendida caudalmente através da osteotomia do trocanter maior. As fraturas foram reduzidas e, em cada segmento ósseo, foram implantados dois a três parafusos e banda de tensão com fio de aço entre os parafusos adjacentes à linha de fratura. Sobre esses implantes aplicou-se cimento ósseo misturado com cefazolina sódica e após o endurecimento prosseguiu-se com a síntese dos tecidos moles com suturas rotineiramente utilizadas na clinica cirúrgica. No período pós-operatório, foram realizadas avaliações até 90 dias após a osteossíntese e observou-se locomoção apropriada em 15 animais. Avaliações radiográficas demonstraram sinais de completa consolidação óssea entre 60 e 90 dias. Falha da estabilização ocorreu em dois casos, obrigando a reintervenção cirúrgica em um deles. A partir dos resultados obtidos, é possível concluir que, em cães com até 16kg de peso, a fixação de fraturas ilíacas utilizando parafusos cimentados com PMMA constitui uma eficiente técnica, que proporciona adequada estabilidade, precoce recuperação funcional e cicatrização óssea.The present study aimed to verify the time for locomotion recovery and bone healing in canine iliac fractures fixated with screws, orthopedic wires and methylmetacrylate bone cement. Sixteen dogs from both genders accidentally hit by a car and showing iliac fractures were included. Dogs aged from 7 months to 11

  18. Biomechanical impact of C2 pedicle screw length in an atlantoaxial fusion construct

    Directory of Open Access Journals (Sweden)

    Risheng Xu

    2014-01-01

    Full Text Available Background: Posterior, atlantoaxial (AA fusions of the cervical spine may include either standard (26 mm or short (16 mm C2 pedicle screws. This manuscript focused on an in vitro biomechanical comparison of standard versus short C2 pedicle screws to perform posterior C1-C2 AA fusions. Methods: Twelve human cadaveric spines underwent C1 lateral mass screw and standard C2 pedicle screw (n = 6 versus short C2 pedicle screw (n = 6 fixation. Six additional controls were not instrumented. The peak torque, peak rotational interval, and peak stiffness of the constructs were analyzed to failure levels. Results: The peak torque to construct failure was not statistically significantly different among the control spine (12.2 Nm, short pedicle fixation (15.5 Nm, or the standard pedicle fixation (11.6 Nm, P = 0.79. While the angle at the peak rotation statistically significantly differed between the control specimens (47.7° of relative motion and the overall instrumented specimens (P < 0.001, the 20.7° of relative rotation in the short C2 pedicle screw specimens was not statistically significantly higher than the 13.7° of relative rotation in the standard C2 pedicle screw specimens (P = 0.39. Similarly, although the average stiffness was statistically significantly lower in control group (0.026 Nm/degree versus the overall instrumented specimens (P = 0.001, the standard C2 pedicle screws (2.54 Nm/degree did not differ from the short C2 pedicle screws (1.69 Nm/degree (P = 0.30. Conclusions: Both standard and short C2 pedicle screws allow for equally rigid fixation of C1 lateral mass-C2 AA fusions. Usage of a short C2 pedicle screw may be an acceptable method of stabilization in carefully selected patient populations.

  19. Treatment of unstable pelvic fractures with an external fixator and combined screwing at iliac crests and pubic symphysis%髂嵴-耻骨联合置钉外固定支架治疗不稳定型骨盆骨折

    Institute of Scientific and Technical Information of China (English)

    张伟; 宋世锋; 刘立柱; 李超艺; 李强; 唐捷; 张丕军

    2016-01-01

    目的 探讨髂嵴-耻骨联合置钉外固定支架治疗不稳定型骨盆骨折的临床疗效. 方法 回顾性分析2013年1月至2014年2月收治的12例不稳定型骨盆骨折患者资料,男8例,女4例;年龄为32 ~57岁,平均42.5岁.致伤原因:交通伤7例,高处坠落伤5例.骨折按Tile分型:B型8例,其中B1型3例,B2型3例,B3型2例;C1型4例.合并伤:休克7例,膀胱损伤1例,四肢长骨骨折6例,关节损伤3例,胸腰椎损伤4例.受伤至手术时间为12h至7d,平均4d.B型骨折采用髂嵴-耻骨联合置钉外固定支架治疗,C1型骨折采用髂嵴-耻骨联合置钉外固定支架加经皮S1骶髂关节螺钉内固定治疗. 结果 12例患者术后获5 ~12个月(平均9个月)随访.无一例患者死亡.本组患者骨折愈合时间为8~13周,平均11.3周.所有患者恢复正常行走,7例患者发生针道浅表感染,无针道深部感染.1例患者出现螺钉松动,无复位丢失、神经损伤及尿道损伤等并发症发生.末次随访时根据Majeed评分标准评定疗效:优10例,良1例,中1例. 结论 髂嵴-耻骨联合置钉外固定支架治疗不稳定型骨盆骨折可恢复骨盆前环的稳定性,临床疗效良好.%Objective To study the clinical efficacy of external fixator and combined screwing at iliac crests and pubic symphysis for the treatment of unstable pelvic fractures.Methods From January 2013 to February 2014,12 cases of unstable pelvic fracture were treated at our department.They were 8 men and 4 women,from 32 to 57 years of age (average,42.5 years).Seven cases were caused by a traffic accident,and 5 by falling from a height.By Tile classification,8 cases were type B (including type B1 in 3 cases,type B2 in 3 and type B3 in 2),and 4 cases type C1.Associated injury included shock in 7 cases,bladder injury in one,limb long bone fracture in 6,joint injury in 3,and thoracic and lumbar injury in 4.The interval from injury to operation averaged 4 days,ranging from 12 hours to 7 days

  20. Bioabsorbable Suture Anchor Migration to the Acromioclavicular Joint: How Far Can These Implants Go?

    Directory of Open Access Journals (Sweden)

    Giovanna Medina

    2014-01-01

    Full Text Available Few complications regarding the use of bioabsorbable suture anchors in the shoulder have been reported. What motivated this case report was the unusual location of the anchor, found in the acromioclavicular joint which, to our knowledge, has never been reported so far. A 53-year old male with previous rotator cuff (RC repair using bioabsorbable suture anchors presented with pain and weakness after 2 years of surgery. A suspicion of retear of the RC led to request of a magnetic resonance image, in which the implant was found located in the acromioclavicular joint. The complications reported with the use of metallic implants around the shoulder led to the development of bioabsorbable anchors. Advantages are their absorption over time, minimizing the risk of migration or interference with revision surgery, less artifacts with magnetic resonance imaging, and tendon-to-bone repair strength similar to metallic anchors. Since the use of bioabsorbable suture anchors is increasing, it is important to know the possible complications associated with these devices.

  1. QWIX螺钉置入内固定修复髌骨骨折:骨折断端的持续动静态加压作用%QWIX screw fixation in repair of patellar fractures:continuous dynamic and static pressure in the broken ends of the bones

    Institute of Scientific and Technical Information of China (English)

    刘杰; 高仕长; 梁安霖

    2014-01-01

    extension apparatus continuity and potential uncoordination of patel ofemoral joint. The aim of patel ar fracture surgery is to restore the smoothness of patel ar articular surface and to maintain the continuity of knee extension apparatus, to provide stable effective fixation, so as to do early functional exercises. OBJECTIVE:To evaluate the clinical effectiveness of a fixation technique for patel ar fractures using QWIX combined with Kirschner wire and wire. METHODS:From September 2011 to September 2012, 30 patients with patel ar fractures were treated using QWIX screws combined with Kirschner wire and wire in the First Affiliated Hospital of Chongqing Medical University, China. There were 17 males and 13 females, at the age of 47.7 years on average. In accordance with the situation of comminuted fracture and the degree of displacement, QWIX screws or QWIX screws+tension band wire or QWIX screws+Kirschner wire+tension band wire were used for fixation. Active and passive knee motion exercises began at 1 day after surgery, without any external fixation. At 6 weeks, 3, 6, 12 months, and 1 year after surgery, the patients were fol owed up in out-patient clinic to identify fracture healing and to make sure whether complications appeared or not. The range of flexion and extension of bilateral knee was measured. The knee function of the affected side was evaluated using Bostman score at 1 year postoperatively. RESULTS AND CONCLUSION:Al patients were fol owed up for 12 to 24 months. 24 cases were healed within 3 months after surgery, and 6 cases were healed within 4 months after surgery, with an average healing time of 3.2 months. With time prolonged, the range of flexion and extension of bilateral knee gradual y increased. The knee function of patients recovered to the level before injury at 1 year after surgery. During fol ow-up, one patient experienced knee pain due to Kirschner wire loosening. No infection, knee pain, fixation failure, or flexion dysfunction occurred in the

  2. 单侧椎弓根钉固定结合椎间融合治疗腰椎间盘突出症30例临床回顾报道%Unilateral Pedicle Screw Fixation Combined With Lumbar Disc Herniation in 30 Cases of Lumbar Disc Herniation

    Institute of Scientific and Technical Information of China (English)

    李加立

    2015-01-01

    Objective Discussion with unilateral pedicle screw ifxation and clinical efifcacy of the treatment of lumbar disc herniation of intervertebral fusion, and to evaluate its clinical value. Methods 30 cases of lumbar disc herniation underwent unilateral pedicle screw fixation combined with interbody fusion for treatment from March 2012~March 2013 in our hospital, surgery in 6 months, 12 months, 18 month, 24 month follow-up, follow-up observations of bone fusion, clinical symptoms as well as occurrence of complications. Results Clinical symptoms of all patients have received varying degrees of ease, clinical after 6 months, 12 months, 18 months, 24 months recovery rates were 76.7%, 83.3%, 90%and 86.7%. Perioperative complication rate was 23.3%, after treatment, symptoms were controlled and improved. Conclusion Clinical unilateral pedicle screw ifxation combined with interbody fusion for lumbar disc herniation is remarkable, worth promoting.%目的:探讨研究单侧椎弓根钉固定结合椎间融合治疗腰椎间盘突出症临床疗效,并评价其临床应用价值。方法给予2012年3月~2013年3月于我院就诊的30例腰椎间盘突出症患者行单侧椎弓根钉固定结合椎间融合术进行治疗,术后于6个月、12个月、18个月、24个月随访,随访观察记录骨融合情况、临床症状缓解情况以及并发症发生情况。结果所有病患的临床症状均得到了不同程度的缓解,临床术后6个月、12个月、18个月、24个月恢复率分别为76.7%、83.3%、90%、86.7%。围手术期并发症发生率为23.3%,经过治疗后症状均得到控制及改善。结论临床采用单侧椎弓根钉固定结合椎间融合术治疗腰椎间盘突出症疗效显著。

  3. Posterior cervical spine arthrodesis with laminar screws. A report of two cases

    International Nuclear Information System (INIS)

    We performed fixation using laminar screws in 2 patients in whom lateral mass screws, pedicle screws or transarticular screws could not be inserted. One was a 56-year-old woman who had anterior atlantoaxial subluxation (AAS). When a guide wire was inserted using an imaging guide, the hole bled massively. We thought the re-insertion of a guide wire or screw would thus increase the risk of vascular injury, so we used laminar screws. The other case was an 18-year-old man who had a hangman fracture. Preoperative magnetic resonance angiography showed occlusion of the left vertebral artery. A laminar screw was inserted into the patent side (i.e., the right side of C2). Cervical pedicle screws are the most biomechanically stable screws. However, their use carries a high risk of neurovascular complications during screw insertion, because the cervical pedicle is small and is adjacent laterally to the vertebral artery, medially to the spinal cord, and vertically to the nerve roots. Lateral mass screws are also reported to involve a risk of neurovascular injuries. The laminar screw method was thus thought to be useful, since arterial injuries could thus be avoided and it could also be used as a salvage modality for the previous misinsertion. (author)

  4. Posterior cervical spine arthrodesis with laminar screws: a report of two cases

    Directory of Open Access Journals (Sweden)

    Sugimoto,Yoshihisa

    2007-04-01

    Full Text Available We performed fixation using laminar screws in 2 patients in whom lateral mass screws, pedicle screws or transarticular screws could not be inserted. One was a 56-year-old woman who had anterior atlantoaxial subluxation (AAS. When a guide wire was inserted using an imaging guide, the hole bled massively. We thought the re-insertion of a guide wire or screw would thus increase the risk of vascular injury, so we used laminar screws. The other case was an 18-year-old man who had a hangman fracture. Preoperative magnetic resonance angiography showed occlusion of the left vertebral artery. A laminar screw was inserted into the patent side (i.e., the right side of C2. Cervical pedicle screws are the most biomechanically stable screws. However, their use carries a high risk of neurovascular complications during screw insertion, because the cervical pedicle is small and is adjacent laterally to the vertebral artery, medially to the spinal cord, and vertically to the nerve roots. Lateral mass screws are also reported to involve a risk of neurovascular injuries. The laminar screw method was thus thought to be useful, since arterial injuries could thus be avoided and it could also be used as a salvage modality for the previous misinsertion.

  5. Early curative effect of transpedicular screw fixation in treatment of thoracolumbar fracture combined with posterior ligamentous complex injuries%经椎弓根钉内固定治疗合并后方韧带复合体损伤胸腰椎骨折早期疗效观察

    Institute of Scientific and Technical Information of China (English)

    曹贵君; 孟纯阳; 张卫红; 孔祥清; 高峰; 吴同申; 陈国武

    2015-01-01

    目的 探讨后路经椎弓根钉内固定治疗合并后方韧带复合体(PLC)损伤的胸腰椎骨折早期临床疗效.方法 回顾性分析2008年7月-2013年3月行手术治疗的合并PLC损伤胸腰椎屈曲分离型骨折患者22例,其中男16例,女6例;年龄23 ~62岁,平均39岁.所有患者病情稳定后,在静吸复合麻醉下行后路椎弓根螺钉内固定术.根据骨折移位的程度及韧带损伤的类型行后外侧和(或)椎体间自体植骨.观察术前、术后3d、随访末期的椎体高度恢复率、Cobb角矫正率、美国脊髓损伤协会(ASIA)分级.结果 所有患者手术顺利,术中未发生手术并发症;患者均获得随访5~51个月(平均26.5个月).骨折复位满意,分离的后部结构闭合.椎体前缘高度术后较术前平均改善20.6% (P <0.01);Cobb角术后较术前平均改善10.60°(P<0.01).术前有神经损伤的8例术后均有不同程度恢复;术后感觉评分较术前平均改善20.7% (P <0.05),运动功能评分较术前改善30.9% (P <0.01).CT三维重建示植骨全部骨性愈合;患者无局部疼痛及内固定物断裂.结论 后路经椎弓根钉内固定手术治疗合并PLC损伤的胸腰椎屈曲分离型骨折短期疗效满意,钉棒固定可以达到满意复位、骨折失稳脊柱的三柱即刻稳定;充分植骨是获得永久性稳定的保障.%Objective To investigate the preliminary clinical result of thoracolumbar fracture combined with posterior ligamentous complex injuries repaired by posterior transpedicular screw fixation.Methods A retrospective review was performed on 22 patients with thoracolumbar flexion-distraction fracture combined with posterior ligamentous complex injuries treated with transpedicular screw fixation from July 2008 to March 2013.There were 16 males and 6 females with mean age of 39 years (range,23-62 years).After medically stable,posterior pedicle screw fixation was performed under intravenousinhalational anesthesia

  6. Cement leakage in pedicle screw augmentation: a prospective analysis of 98 patients and 474 augmented pedicle screws.

    Science.gov (United States)

    Mueller, Jan U; Baldauf, Joerg; Marx, Sascha; Kirsch, Michael; Schroeder, Henry W S; Pillich, Dirk T

    2016-07-01

    OBJECTIVE Loosening and pullout of pedicle screws are well-known problems in pedicle screw fixation surgery. Augmentation of pedicle screws with bone cement, first described as early as 1975, increases the pedicle-screw interface and pullout force in osteoporotic vertebrae. The aim of the present study was to identify cement leakage and pulmonary embolism rates in a large prospective single-center series of pedicle screw augmentations. METHODS All patients who underwent cement-augmented pedicle screw placement between May 2006 and October 2010 at the authors' institution were included in this prospective cohort study. Perivertebral cement leakage and pulmonary cement embolism were evaluated with a CT scan of the area of operation and with a radiograph of the chest, respectively. RESULTS A total of 98 patients underwent placement of cement-augmented pedicle screws; 474 augmented screws were inserted in 237 vertebrae. No symptomatic perivertebral cement leakage or symptomatic pulmonary cement embolism was observed, but asymptomatic perivertebral cement leakage was seen in 88 patients (93.6%) and in 165 augmented vertebrae (73.3%). Cement leakage most often occurred in the perivertebral venous system. Clinically asymptomatic pulmonary cement embolism was found in 4 patients (4.1%). CONCLUSIONS Perivertebral cement leakage often occurs in pedicle screw augmentation, but in most cases, it is clinically asymptomatic. Cement augmentation should be performed under continuous fluoroscopy to avoid high-volume leakage. Alternative strategies, such as use of expandable screws, should be examined in more detail for patients at high risk of screw loosening. PMID:26943258

  7. Screw-locking wrench

    Science.gov (United States)

    Vranish, John M. (Inventor)

    2007-01-01

    A tool comprises a first handle and a second handle, each handle extending from a gripping end portion to a working end portion, the first handle having first screw threads disposed circumferentially about an inner portion of a first through-hole at the working end portion thereof, the second handle having second screw threads disposed circumferentially about an inner portion of a second through-hole at the working end portion thereof, the first and second respective through-holes being disposed concentrically about a common axis of the working end portions. First and second screw locks preferably are disposed concentrically with the first and second respective through-holes, the first screw lock having a plurality of locking/unlocking screw threads for engaging the first screw threads of the first handle, the second screw lock having a plurality of locking/unlocking screw threads for engaging the second screw threads of the second handle. A locking clutch drive, disposed concentrically with the first and second respective through-holes, engages the first screw lock and the second screw lock. The first handle and the second handle are selectively operable at their gripping end portions by a user using a single hand to activate the first and second screw locks to lock the locking clutch drive for either clockwise rotation about the common axis, or counter-clockwise rotation about the common axis, or to release the locking clutch drive so that the handles can be rotated together about the common axis either the clockwise or counter-clockwise direction without rotation of the locking clutch drive.

  8. Removal of internal fixation--the effect on patients' complaints: a study of 66 cases of removal of internal fixation after malleolar fractures

    DEFF Research Database (Denmark)

    Jacobsen, S; Honnens de Lichtenberg, M; Jensen, C M; Tørholm, C

    1994-01-01

    typically soreness over implant and cicatrix, reduced movement of the ankle joint, and strain-related pain. About 75% of these patients reported improvement after removal. The AO mode of fixation, i.e., typically by lateral semitubular plating and transsyndesmotic screw and a medial screw or pins, and the...

  9. MANAGEMENT OF INTERTROCHANTER FRACTURES OF HIP WITH DYNAMIC HIP SCREW : A CLINICAL STUDY

    Directory of Open Access Journals (Sweden)

    Nageshwara Rao

    2015-09-01

    Full Text Available BACKGROUND & OBJECTIVES: Fractures of proximal femur are the most commonly encountered fractures by orthopedic surgeon. Many management techniques are described in literature but internal fixation with Dynamic Hip Screw is the treatment of choice. This study analyzes the outcome of treatment of intertrochanteric fra cture with Dynamic Hip Screw. MATERIALS AND METHODS: Between April 2010 and May 2012, 40 patients with intertrochanteric fracture admitted in the department of Orthopedics, Government General Hospital, Kurnool were treated with internal fixation with Dynam ic Hip Screw and the results were evaluated using Kyle’s criteria. RESULTS : Incidence among both sexes was same. Average age of occurrence was 62.7 years, with level of osteoporosis Singh’s index 3 or 4. There were 25% excellent, 50% good, 15% fair, 10% po or results. CONCLUSION : Internal fixation with Dynamic Hip Screw is the treatment of choice for treatment of intertrochanteric fractures.

  10. Treatment strategies for early neurological deficits related to malpositioned pedicle screws in the lumbosacral canal

    Science.gov (United States)

    Du, J-Y.; Wu, J-S.; Wen, Z-Q.

    2016-01-01

    Objectives To employ a simple and fast method to evaluate those patients with neurological deficits and misplaced screws in relatively safe lumbosacral spine, and to determine if it is necessary to undertake revision surgery. Methods A total of 316 patients were treated by fixation of lumbar and lumbosacral transpedicle screws at our institution from January 2011 to December 2012. We designed the criteria for post-operative revision scores of pedicle screw malpositioning (PRSPSM) in the lumbosacral canal. We recommend the revision of the misplaced pedicle screw in patients with PRSPSM = 5′ as early as possible. However, patients with PRSPSM DOI: 10.1302/2046-3758.52.2000477. PMID:26868892

  11. A Technique of Superficial Medial Collateral Ligament Reconstruction Using an Adjustable-Loop Suspensory Fixation Device

    OpenAIRE

    Deo, Shaneel; Getgood, Alan

    2015-01-01

    This report describes superficial medial collateral ligament reconstruction of the knee using a novel method of graft fixation with the ACL Tightrope RT (Arthrex, Naples, FL). After tibial fixation with either a standard interference screw or staple, femoral fixation of the semitendinosus tendon is performed with the adjustable-loop suspensory fixation device, which allows for both initial graft tensioning and re-tensioning after cyclical knee range of motion. This provides the ability for th...

  12. Locking plate fixation for proximal humerus fractures.

    LENUS (Irish Health Repository)

    Burke, Neil G

    2012-02-01

    Locking plates are increasingly used to surgically treat proximal humerus fractures. Knowledge of the bone quality of the proximal humerus is important. Studies have shown the medial and dorsal aspects of the proximal humeral head to have the highest bone strength, and this should be exploited by fixation techniques, particularly in elderly patients with osteoporosis. The goals of surgery for proximal humeral fractures should involve minimal soft tissue dissection and achieve anatomic reduction of the head complex with sufficient stability to allow for early shoulder mobilization. This article reviews various treatment options, in particular locking plate fixation. Locking plate fixation is associated with a high complication rate, such as avascular necrosis (7.9%), screw cutout (11.6%), and revision surgery (13.7%). These complications are frequently due to the varus deformation of the humeral head. Strategic screw placement in the humeral head would minimize the possibility of loss of fracture reduction and potential hardware complications. Locking plate fixation is a good surgical option for the management of proximal humerus fractures. Complications can be avoided by using better bone stock and by careful screw placement in the humeral head.

  13. Preliminary results in anterior cervical discectomy and fusion with an experimental bioabsorbable cage – clinical and radiological findings in an ovine animal model

    OpenAIRE

    Daentzer, Dorothea; Floerkemeier, Thilo; Bartsch, Ivonne; Masalha, Waseem; Welke, Bastian; Hurschler, Christof; Kauth, Theresa; Kaltbeitzel, Daniel; HOPMANN, Christian; Kujat, Bernd; Kalla, Katharina

    2013-01-01

    Background Bioabsorbable implants are not widely used in spine surgery. This study investigated the clinical and radiological findings after anterior cervical discectomy and fusion (ACDF) in an ovine animal model with an experimental bioabsorbable cage consisting of magnesium and polymer (poly-ϵ-caprolactone, PCL) in comparison to a tricortical bone graft as the gold standard procedure. Materials and Methods 24 full-grown sheep had ACDF of C3/4 and C5/6 with an experimental bioabsorbable impl...

  14. Minimally invasive percutanuous cannulated pedicle screw system fixation for the treatment of thoracolumbar flexion-distraction fracture without neurologic impairment%微创经皮空心椎弓根固定系统治疗无神经功能障碍的屈曲牵张型胸腰椎骨折

    Institute of Scientific and Technical Information of China (English)

    张志成; 孙天胜; 刘智; 郭永智; 李连华

    2011-01-01

    Objective:To explore the feasibility and effect of percutanuous cannulated pedicle screw AF system fixation for the treatment of thoracolumbar flexion - distraction fracture without neurologic impairment. Methods: From June 2008 to June 2010,21 patients with thoracolumbar flexion-distraction fracture were treated with percutanuous cannulated pedicle screw fixation. There were 16 males and 5 females with the mean age of 32.7 years ranging from 23 to 55 years. Injured levels 5 cases was in T12,13 was in L1;3 was in L;. According to classification of AO,B1 was in 13 cases,B2 was in 8 cases. ASIA grade of all the patients were grade E. The mean operative time, bleeding volume, lengths of stay were evaluated. All the patients took the X -ray and three-dimensional CT reconstruction to observe the fracture healing and to measure the height of the anterior border of fracture vertebral body and the Cobb angle of kyphosis. The visual analogue scales (VAS) were compared preoperation and postoperation. The clinical effects were analyzed according to Oswestry Disability Index (ODI) from 10 aspects,including pain intensity .personal care, lifting, walking, sitting, standing, sleeping, sex life, social life, traveling. Results-.All the operations were successful and the mean time was (109.0±16.0) min,blood loss was (90.0±15.0) ml,lengths of stay was (7.7±2.3) d. No postoperative neurological deficits or wound infection occurred. One case occurred subcutaneous fluid of incision and 1 case occurred delayed healing of incision. Fifteen patients were followed up with an average of 16.7 months (12-33 months). The VAS score improved from preoperative 8.3±1.7 to 1.8±1.2 at final follow up (P0.05).There were satisfactory fracture reduction and good position of internal fixation, and no loss of reduction within 12 months and no fixation failure in follow-up. Conclusion: The minimally invasive percutaneous cannulated pedicle screw fixation technique is feasible in treatment of

  15. 下腰椎病变椎弓根螺钉系统内固定术后急性感染的临床治疗%Clinical treatment of acute infection of lower lumbar spine under pedicle screw fixation system

    Institute of Scientific and Technical Information of China (English)

    许建柱; 胡文跃

    2011-01-01

    OBJECTIVE To investigate the effect of the clinical treatment of acute infection under the lumbar spine after pedicle screw system. METHODS A total of 38 patients were treated under the lumbar spine in patients with pedicle screw system during the course of acute infection caused by the gap from Jan 2009 to Apr 2010. Towards the infected groupi according to the time of infection, the different clinical treatment methods were given. 57 cases treated in the same period under the lumbar pedicle screw system variable line fixed after a good recovery in patients were set as non-infected group. The patient's clinical manifestations. Diagnosis, treatment and prognosis of non-infected group of the indicators were analyzed. RESULTS After treatment, patients with acute infection, the patient showed better wound healing degrees, no recurrence of swelling, leaking and other adverse symptoms, and other discomfort. 38 patients, 1 patient lost, its 37 patients were followed up for 1 year, infection rate was 91. 89% good, the fine non-infected group was 92. 98% , two groups had no significant difference. CONCLUSION The lesions incision and drainage, lesion debridement, internal fixation removal surgery combined with intravenous antibiotics) sensitive treatment of lumbar pedicle screw system for acute postoperative infection is a more effective clinical treatment.%目的 探讨椎弓螺钉系统内固定术治疗下腰椎病变后急性感染的临床治疗效果.方法选择2009年1月-2010年4月收治的38例下腰椎病变行椎弓螺钉系统内固定过程中引发间隙急性感染患者,作为感染组,同一时期收治的57例下腰椎病变行椎弓螺钉系统内固定术后恢复良好的患者为非感染组,将两组患者的临床表现、诊断依据、治疗方法以及预后各项指标进行对比分析.结果急性感染患者经治疗后,患者的伤口均呈较好愈合度,未再次出现红肿、渗出等症状;38例患者,除有1

  16. Parafuso de massa lateral do atlas para fixação da coluna cervical superior: resultados cirúrgicos Tornillos de masa lateral del atlas para la fijación de la columna cervical superior: resultados quirúrgicos Lateral mass screws of the atlas for upper cervical spine fixation: surgical results

    Directory of Open Access Journals (Sweden)

    Enrico Ghizoni

    2011-01-01

    alcanzar la fusión y la estabilidad de la columna cervical, y con el conocimiento de la anatomía y de la técnica quirúrgica es posible obtenerse excelentes resultados.OBJECTIVE: To present the surgical results of a case series of upper cervical spine stabilization with the use of lateral mass screws of the atlas. METHODS: Retrospective review of the surgical results of patients submitted to upper cervical spine stabilization with the use of lateral mass screws of the atlas. RESULTS: Six patients were operated in the period between January 2009 to April 2010, four men and two women. There was no permanent morbidity or mortality in the presented series. The main cause of atlanto-axial instability was trauma and there was just one case of odontoid pathologic fracture from a prostate metastasis. Axis fixation was achieved with the use of three different screw techniques (pars, pedicle and laminar, with equal distribution among the patients. CONCLUSIONS: The use of lateral mass screws of the atlas is an important technique to achieve fusion and stability of the upper cervical spine and with the knowledge of the anatomy and of the surgical technique good results can be achieved.

  17. 后路经椎弓根内固定联合椎体成形术对高龄胸腰段脊椎骨折的疗效研究%Effects of in Elderly Patients of Thoracolumbar Vertebral Fractures by Posterior Pedicle Screw Internal Fixation Combined with Vertebral Angioplasty

    Institute of Scientific and Technical Information of China (English)

    冉仁国; 王齐兵

    2016-01-01

    , mean intraoperative blood loss, postoperative Cobb's angle, stenosis rate, vertebral compression ratio compared to preoperative have greatly improved (P0.05). Occurred in 2 cases of spinal canal leakage of bone cement, internal ifxation nail breakage of 3 cases did not occur abdominal parenchymal organs injury and screw withdrawal and so on complications. Conclusion:Through the posterior transpedicular screw system internal fixation, vertebral body plasty combination in the treatment of thoracolumbar spine with excellent biomechanical properties and improve the injured vertebral morphological integrity and strength, postoperative complications and prognosis of the patients with good effect, the effect is signiifcant.

  18. Clear Zone Formation around Screws in the Early Postoperative Stages after Posterior Lumbar Fusion Using the Cortical Bone Trajectory Technique

    OpenAIRE

    Ninomiya, Koshi; Iwatsuki, Koichi; Ohnishi, Yu-ichiro; Ohkawa, Toshika; Yoshimine, Toshiki

    2015-01-01

    Study Design Retrospective study. Purpose To evaluate the initial fixation using the cortical bone trajectory (CBT) technique for posterior lumbar fusion through assessment of the clear zones around the screws and the risk factors involved. Overview of Literature Postoperative radiolucent zones (clear zones) are an indicator of poor conventional pedicle screw fixation. Methods Between January 2013 and April 2014, 19 patients (8 men and 11 women) underwent posterior lumbar interbody fusion or ...

  19. Hollow-Bone-Graft Dynamic Hip Screw Can Fix and Promote Bone Union after Femoral Neck Fracture: an Experimental Research

    OpenAIRE

    SHEN, Jia-zuo; YAO, Jian-fei; LIN, Da-sheng; Lian, Ke-jian; Ding, Zhen-qi; Lin, Bin; GUO, Zhi-min; Zhang, Ming-Hua; Li, Qiang; LI, Lin; Qi, Peng

    2012-01-01

    Background: Delayed bone union, nonunion or osteonecrosis often occur after femoral neck fractures in young adults. Secondary bone healing requires strong internal fixation, intramedullary pressure reduction and early functional exercise. Objective: To compare bone healing of femoral neck fractures treated with hollow-bone-graft dynamic hip screws (Hb-DHS) and standard dynamic hip screws (DHS) in an animal model. Design: Testing of specifically designed fixation devices in a pig animal model....

  20. Hollow-Bone-Graft Dynamic Hip Screw Can Fix and Promote Bone Union after Femoral Neck Fracture: an Experimental Research

    OpenAIRE

    Jia-zuo SHEN, Jian-fei YAO, Da-sheng LIN, Ke-jian LIAN, Zhen-qi DING, Bin LIN, Zhi-min GUO, Ming-hua ZHANG, Qiang LI, Lin LI, Peng QI

    2012-01-01

    Background: Delayed bone union, nonunion or osteonecrosis often occur after femoral neck fractures in young adults. Secondary bone healing requires strong internal fixation, intramedullary pressure reduction and early functional exercise.Objective: To compare bone healing of femoral neck fractures treated with hollow-bone-graft dynamic hip screws (Hb-DHS) and standard dynamic hip screws (DHS) in an animal model.Design: Testing of specifically designed fixation devices in a pig animal model.In...

  1. Biomechanical testing of a unique built-in expandable anterior spinal internal fixation system

    OpenAIRE

    Zhou, Chu-Song; Xu, Yan-Fang; Zhang, Yu; Chen, Zhong; Lv, Hai

    2014-01-01

    Background Expandable screws have greater pullout strength than conventional screws. The purpose of this study was to compare the biomechanical stability provided by a new built-in expandable anterior spinal fixation system with that of 2 commonly used anterior fixation systems, the Z-Plate and the Kaneda, in a porcine partial vertebral corpectomy model. Methods Eighteen porcine thoracolumbar spine specimens were randomly divided into 3 groups of 6 each. A vertebral wedge osteotomy was perfor...

  2. The Use of MMF Screws: Surgical Technique, Indications, Contraindications, and Common Problems in Review of the Literature

    OpenAIRE

    Cornelius, Carl-Peter; Ehrenfeld, Michael

    2010-01-01

    Mandibulo-maxillary fixation (MMF) screws are inserted into the bony base of both jaws in the process of fracture realignment and immobilisation. The screw heads act as anchor points to fasten wire loops or rubber bands connecting the mandible to the maxilla. Traditional interdental chain-linked wiring or arch bar techniques provide the anchorage by attached cleats, hooks, or eyelets. In comparison to these tooth-borne appliances MMF screws facilitate and shorten the way to achieve intermaxil...

  3. [Sacroiliac fixation: a new technique after pelvic trauma].

    Science.gov (United States)

    Hoffmann, E; Levassor, N; Rillardon, L; Lavelle, G; Guigui, P

    2003-12-01

    We propose a new technique for sacroiliac fixation for the treatment of pelvic fracture with vertical and horizontal instability (Tile class C). This fixation technique allows control of vertical displacement while allowing, if needed, a certain degree of movement in the horizontal plane to facilitate reduction of anterior lesions. The technique involves insertion of two sacral screws, one in S1 and one in S2, and two iliac screws. The iliac screws are inserted in the posterior iliac crest through two sacroiliac connectors placed on a rod linking the two sacral screws. Vertical displacement is controlled by blocking the screw heads on the connecting rod. If needed, a certain degree of horizontal mobility of the half pelvis can be allowed by loosening the connectors on the rods. This technique was used for 4 patients. Anatomic reduction was achieved and no secondary movement of the osteosynthesis material nor secondary displacement were observed. The quality of the fixation allowed rapid weight bearing in the standing position and early walking without crutches. This type of fixation can only be used for type C12 fractures in the Tile classification. PMID:14726839

  4. 持续闭式引流(VSD)结合骨水泥抗生素链珠治疗腰椎骨折椎弓根钉棒系统内固定术后早期感染%Treatment of early postoperative infection of lumbar fracture internal fixation of pedicle screw rod system with vacuum sealing drainage(VSD)combined with antibiotic bone cement chain

    Institute of Scientific and Technical Information of China (English)

    朱余龙; 朱海涛; 丁德刚; 徐亮

    2014-01-01

    目的:探讨持续闭式引流(VSD)结合骨水泥抗生素链珠治疗腰椎骨折椎弓根钉棒系统内固定术后早期感染的临床疗效。方法2010年3月一2014年3月,使用持续闭式引流(VSD)结合骨水泥抗生素链珠治疗腰椎骨折椎弓根钉棒系统内固定术后早期感染11例,随访其临床效果。结果11例患者均得到随访,随访时间8—12月,平均10.5月。手术后感染治愈,无一例需取出原内固定物重新或者更换固定材料。结论持续闭式引流(VSD)结合骨水泥抗生素链珠治疗腰椎骨折椎弓根钉棒系统内固定术后早期感染操作简单、安全有效,可以作为治疗腰椎骨折椎弓根钉棒系统内固定术后早期感染手段之一。%Objective: To investigate the efficacy of the treatment of early postoperative infection of umbar fracture internal fixation of pedicle screw rod system with VSD combined with antibiotic bone cement chain. Methods: from 2010 March to 2014 March, the use of continuous closed drainage (VSD) combined with antibiotic bone cement bead chain, lumbar fracture internal fixation of pedicle screw rod system treatment of early postoperative infection in 11 cases, folow-up clinical results. Results: 11 patients were folowed up from 8-12 months, with an average of 8.5 months. Cured of infection after surgery, no case of need to remove or replace the original re-fixed within the implant material. Conclusion: The continuous closed drainage (VSD) combined with antibiotic bone cement beads chain to treat early infection is simple, safe and effective treatment of lumbar fracture internal fixation of pedicle screw rod system can be used as a means of early postoperative infection.

  5. 强化螺钉治疗老年腰椎管狭窄近中期疗效%The short and midterm clinical effect of pedicle screw fixation with bone cement augmentation in the treatment of senile lumbar spinal stenosis

    Institute of Scientific and Technical Information of China (English)

    瞿岱彪; 黄圣升; 吴华; 刘礼金

    2015-01-01

    目的:评价骨水泥强化椎弓根螺钉内固定治疗伴老年腰椎管狭窄症的近中期临床疗效。方法2012年6月至2014年6月间应用骨水泥强化椎弓根螺钉治疗老年性腰椎管狭窄患者24例,所有患者术前均行骨密度测定诊断为骨质疏松症。采用VAS、JOA下腰痛评分及Oswestry功能障碍指数问卷表(ODI)评分标准评价临床疗效。结果24例患者随访6-24个月,平均(11.50±2.11)个月,不适症状均得到一定改善。 VAS评分术前(7.55±1.30)、术后3个月为(3.65±0.87)、术后6个月为(3.15±0.71)、末次为(2.83±2.04);JOA评分术前为(8.66±7.01)、术后3个月为(14.09±2.07)、术后6个月为(16.88±1.95)、末次随访为(17.33±1.74);ODI评分术前为(0.71±0.31)、术后3个月为(0.44±0.12)、术后6个月为(0.31±0.11)、末次随访为(0.29±0.07)。术后3个月、6个月、末次随访所有评价指标分别与术前对比,差异均有统计学意义(P<0.05)。随访时复查相关影像学资料示只有1例因外伤出现椎弓根螺钉松动,末次随访椎间融合率高达87%。结论对于老年性合并骨质疏松的腰椎管狭窄症患者,应用骨水泥强化椎弓根螺钉技术临床疗效确切,有术后椎间融合率高、发生内固定松动率低、二次手术风险低等优势。%Objective To observe the short and midterm clinical effect of pedicle screw fixation with bone cement augmenta-tion in the treatment of senile lumbar spinal stenosis. Methods From June 2012 to June 2014,24 patients with Lumbar Spinal Stenosis and osteoporosis were treated by posterior decompression,intervertebral fusion with pedicle screw fixation with bone ce-ment augmentation. Osteoporosis was diagnosed by dual-energy X-ray absorptiometry (DEXA) examination in all cases preopera-tively. The clinical results were investigated by measuring VAS and JOA and ODI scoring. Results 24 patients were followed up from 6 to 24 months (average 11.50

  6. 经皮椎体成形术结合椎弓根螺钉内固定治疗胸腰段骨质疏松性爆裂性骨折%A combination of percutaneous vertebroplasty and pedicle screw fixation for thoracolumbar osteoporotic burst fractures

    Institute of Scientific and Technical Information of China (English)

    赵国辉; 陈孜; 金丹杰; 徐南伟; 张云坤

    2015-01-01

    背景:椎体成形术是治疗骨质疏松性骨折的有效方法,但是对于伴有椎体后壁破裂、椎管内存在压迫的骨折,单纯采用椎体成形并不能够达到满意的治疗效果。目的:探讨经皮椎体成形术(PVP)结合后路椎弓根螺钉内固定术治疗后壁破裂伴椎管内有骨片移位(AO分型:A3/A4)的骨质疏松性椎体骨折(OVCF)的临床疗效。方法:回顾分析2011年5月至2014年9月经CT证实为后壁破裂伴椎管内有骨片移位的椎体骨折患者11例的病例资料。男2例,女9例,年龄55~69岁,平均60.6岁。所有患者均接受PVP+椎弓根螺钉内固定手术,损伤节段:T111例, T124例,L14例,L22例。记录患者术前、术后1周和末次随访的疼痛视觉评分(VAS),Cobb角,椎体前缘、后缘高度。结果:手术均获得成功,2例出现骨水泥泄漏(1例前方泄漏、1例上方泄漏),无经后壁向椎管内泄漏病例。本组患者全部获得随访,时间6~36个月,平均20个月。1例损伤椎上方左侧椎弓根螺钉移位至椎间隙。术前VAS评分,椎体前柱、后柱高度,Cobb角,与术后1周、末次随访时比较,差异均有统计学意义(P<0.01)。结论:对于有后壁破裂伴椎管内有骨片移位的骨质疏松性椎体骨折,PVP+椎弓根螺钉内固定是一种值得选择的治疗方案。%Background: Percutancons vertebroplasty (PVP) is an effective treatment for osteoporotic vertebral compression fracture (OVCF). But when the OVCF combined with posterior wall rupture accompanied by bone fragment displacement with ver-tebral canal, it is not suitable to use PVP only. Objective:To evaluate therapeutic effects of a combination of PVP and posterior pedicle screw internal fixation for the treat-ment of OVCF with posterior wall rupture accompanied by bone fragment displacement within vertebral canal (AO type:A3/A4). Methods: Eleven patients with OVCF with posterior

  7. Fixation strength analysis of cup to bone material using finite element simulation

    Science.gov (United States)

    Anwar, Iwan Budiwan; Saputra, Eko; Ismail, Rifky; Jamari, J.; van der Heide, Emile

    2016-04-01

    Fixation of acetabular cup to bone material is an important initial stability for artificial hip joint. In general, the fixation in cement less-type acetabular cup uses press-fit and screw methods. These methods can be applied alone or together. Based on literature survey, the additional screw inside of cup is effective; however, it has little effect in whole fixation. Therefore, an acetabular cup with good fixation, easy manufacture and easy installation is required. This paper is aiming at evaluating and proposing a new cup fixation design. To prove the strength of the present cup fixation design, the finite element simulation of three dimensional cup with new fixation design was performed. The present cup design was examined with twist axial and radial rotation. Results showed that the proposed cup design was better than the general version.

  8. Use of tightrope fixation in ankle syndesmotic injuries

    Institute of Scientific and Technical Information of China (English)

    Julian Maempel; Anthony Ward; Tim Chesser; Michael Kelly

    2014-01-01

    Objective:Conventional fixation of syndesmotic injuries with screws remains problematic.A novel fibrewire device (Tightrope(R)) has suggested advantages.However,small case series have reported high soft tissue complication rates.The purpose of our study was to quantify complication rates and further procedures in patients treated with Tightropes.A secondary objective was to determine incidence of complications and further procedures in those treated with syndesmotic screws over the same period.Methods:All patients undergoing syndesmotic fixation for ankle fracture between May 2008 and October 2009 were retrospectively reviewed.Incidence of complications,secondary procedures,maintenance of syndesmotic reduction and time spent on non-weight bearing were recorded.Family doctors were contacted for those treated with Tightropes to check for any complications managed elsewhere.Results:Thirty-five patients required syndesmotic fixation,in which 12 were treated with Tightropes.They were followed up in clinic for a mean of 12.4 weeks.Family doctors were contacted at mean 14.6 months after treatment to determine any complications suffered.There were no complications attributable to method of fixation.In this series,12 patients underwent 13 procedures and no patient had recurrent diastasis at discharge; 23 patients treated with screw fixation underwent 45 procedures (19 were screw removals).There was 1 case ofsyndesmotic diastasis.Screw removal resulted in 2 minor complications.Conclusion:Tightrope fixation provideds effective syndesmotic fixation that is maintained at discharge.We do not experience soft tissue complications reported elsewhere.

  9. INTER TROCHANTERIC # NECK FEMUR FIXATION WITH TFN– 250 CASES.

    Directory of Open Access Journals (Sweden)

    Prasad Vijaykumar

    2013-04-01

    Full Text Available INTRODUCTION: Increasing number of hip fractures constitutes a hea lth care burden .U nstable intertrochanteric fractures treatment has a moderat e complication rate. Osteoporosis, fracture geometry, and the success of surgical treatment are strong predictors of outcome. The surgeon can control fracture reduction , implant selection, and implant placement. Options available for Unstable Intertrochanteric Nec k Femur Fracture Fixation are:- 1. DYNAMIC HIP SCREW AND SIDE PLATE.WITH OR WITHOUT USE OF DEROTATION SCREW OR TROCHANTERIC STABILISATION PLATE. 2. 95^ FIXED ANGLE DCS SCREW+ PLATE OR BLADE PLATE. 3. PROXIMAL FEMORAL NAIL.

  10. 加压钢板及螺钉前外侧与内侧入路修复肱骨中下段骨折:疗效及安全性评价%Anterolateral and medial approach fixation with compression plate and screw for middle and inferior humeral fractures:efficacy and safety

    Institute of Scientific and Technical Information of China (English)

    吴畏; 汪海波

    2015-01-01

    BACKGROUND:Reduction and fixation are presently used for middle and inferior humeral fractures. The methods of fixation approach include anterolateral (including modified upper arm anterolateral), posterior and medial approaches. The repair approach of middle and inferior humeral fractures remains controversial. OBJECTIVE:To compare efficiency and safety of anterolateral and medial approach fixation with compression plate and screw for middle and inferior humeral fractures. METHODS:A total of 90 cases of middle and inferior humeral fractures treated in Chongqing Red Cross Hospital were equaly and randomly divided into experimental group and control group. In the control group, patients were subjected to compression plate and screw through anterolateral approach. In the experimental group, patients were subjected to compression plate and screw through medial approach. Operation time, intraoperative blood loss, complications and the recovery of shoulder joint and elbow joint function were compared in patients of both groups. RESULTS AND CONCLUSION:Intraoperative blood loss was significantly lower in the experimental group than in the control group (P 0.05). During 6 months of folow-up, no significant difference in shoulder joint function Neer score and elbow joint function Mayo score was detected between the two groups (P > 0.05). During the folow-up period, no wound infection, bone nonunion or chronic osteomyelitis appeared in both groups. These data confirm that the effects of medial approach and anterolateral approach for middle and inferior humeral fractures are similar. Medial approach leads to less blood loss, can effectively make up for the defects of the traditional repair scheme, and can be considered as one of fixation approach for middle and inferior humeral fractures.%背景:目前对肱骨中下段骨折主要采用复位内固定治疗,内固定入路方式主要有3种:前外侧入路(包括改良上臂前外侧入路)、后侧入路以及内

  11. DLC screw preload. Loosening prevention

    Directory of Open Access Journals (Sweden)

    Ivete Aparecida de Mattias Sartori

    2008-01-01

    Full Text Available The screw loosening is a reason to prosthetic rehabilitation failure. However, the DLC (Diamond-like carbon screw treatment lead thefriction decrease and sliding between the components, which increases the screw preload benefit and decreases the chance of looseningoccurrence. This case shows a clinical indication of the association of the correct preload applied and the DLC screw, which can be considered an optimized protocol to solve screw loosening recidivate of unitary prosthesis in anterior maxillary site.

  12. Comparison of in vivo acute stent recoil between the bioabsorbable everolimus-eluting coronary stent and the everolimus-eluting cobalt chromium coronary stent: insights from the ABSORB and SPIRIT trials

    DEFF Research Database (Denmark)

    Tanimoto, Shuzou; Serruys, Patrick W; Thuesen, Leif;

    2007-01-01

    OBJECTIVES: This study sought to evaluate and compare in vivo acute stent recoil of a novel bioabsorbable stent and a metallic stent. BACKGROUND: The bioabsorbable everolimus-eluting coronary stent (BVS) is composed of a poly-L-lactic acid backbone, coated with a bioabsorbable polymer containing ...

  13. Percutaneous reduction and fixation of intraarticular calcaneal fractures

    OpenAIRE

    Schepers, Tim; Vogels, Lucas; Schipper, Inger; Patka, Peter

    2008-01-01

    textabstractObjective: Percutaneous reduction by distraction and subsequent percutaneous screw fixation to restore calcaneal and posterior talocalcaneal facet anatomy. The aim of this technique is to improve functional outcome and to diminish the rate of secondary posttraumatic arthrosis compared to conservative treatment and, secondly, to reduce infectious complications compared to open reduction and internal fixation (ORIF). Indications: Sanders type II-IV displaced intraarticular calcaneal...

  14. Lateral Mass Fixation in Subaxial Cervical Spine: Anatomic Review

    OpenAIRE

    Mohamed, Elrahmany; Ihab, Zidan; Moaz, Anwar; Ayman, Nabawi; Haitham, Abo-elw

    2012-01-01

    Introduction The cervical spine is a highly mobile segment of the spinal column, liable to a variety of diseases and susceptible to trauma. It is a complex region where many vital structures lie in close proximity. Lateral mass screw fixation has become the method of choice in stabilizing subaxial cervical spine among other posterior cervical fixation techniques whenever the posterior elements are absent or compromised. Objective This study examined cervical specimens of cadavers and cervical...

  15. Decompressive cervical laminectomy and lateral mass screw-rod arthrodesis. Surgical analysis and outcome

    Directory of Open Access Journals (Sweden)

    Obaidat Mouness H

    2011-05-01

    Full Text Available Abstract Background This study evaluates the outcome and complications of decompressive cervical Laminectomy and lateral mass screw fixation in 110 cases treated for variable cervical spine pathologies that included; degenerative disease, trauma, neoplasms, metabolic-inflammatory disorders and congenital anomalies. Methods A retrospective review of total 785 lateral mass screws were placed in patients ages 16-68 years (40 females and 70 males. All cases were performed with a polyaxial screw-rod construct and screws were placed by using Anderson-Sekhon trajectory. Most patients had 12-14-mm length and 3.5 mm diameter screws placed for subaxial and 28-30 for C1 lateral mass. Screw location was assessed by post operative plain x-ray and computed tomography can (CT, besides that; the facet joint, nerve root foramen and foramen transversarium violation were also appraised. Results No patients experienced neural or vascular injury as a result of screw position. Only one patient needed screw repositioning. Six patients experienced superficial wound infection. Fifteen patients had pain around the shoulder of C5 distribution that subsided over the time. No patients developed screw pullouts or symptomatic adjacent segment disease within the period of follow up. Conclusion decompressive cervical spine laminectomy and Lateral mass screw stabilization is a technique that can be used for a variety of cervical spine pathologies with safety and efficiency.

  16. BIOMECHANICAL EVALUATION OF THE INFLUENCE OF CERVICAL SCREWS TAPPING AND DESIGN

    Science.gov (United States)

    Silva, Patricia; Rosa, Rodrigo César; Shimano, Antonio Carlos; Albuquerque de Paula, Francisco José; Volpon, José Batista; Aparecido Defino, Helton Luiz

    2015-01-01

    Objective: To assess if the screw design (self-drilling/self-tapping) and the pilot hole tapping could affect the insertion torque and screw pullout strength of the screw used in anterior fixation of the cervical spine. Methods: Forty self-tapping screws and 20 self-drilling screws were inserted into 10 models of artificial bone and 10 cervical vertebrae of sheep. The studied parameters were the insertion torque and pullout strength. The following groups were created: Group I-self-tapping screw insertion after pilot hole drilling and tapping; Group II-self-tapping screw insertion after pilot hole drilling without tapping; Group III-self-drilling screw insertion without drilling and tapping. In Groups I and II, the pilot hole had 14.0 mm in depth and was made with a 3mmn drill, while tapping was made with a 4mm tap. The insertion torque was measured and the pullout test was performed. The comparison between groups was made considering the mean insertion torque and the maximum mean pullout strength with the variance analysis (ANOVA; p≤ 0.05). Results: Previous drilling and tapping of pilot hole significantly decreased the insertion torque and the pullout strength. Conclusion: The insertion torque and pullout strength of self-drilling screws were significantly higher when compared to self-tapping screws inserted after pilot hole tapping. PMID:27004189

  17. Effect of different radial hole designs on pullout and structural strength of cannulated pedicle screws.

    Science.gov (United States)

    Chen, Hsin-Chang; Lai, Yu-Shu; Chen, Wen-Chuan; Chen, Jou-Wen; Chang, Chia-Ming; Chen, Yi-Long; Wang, Shih-Tien; Cheng, Cheng-Kung

    2015-08-01

    Cannulated pedicle screws are designed for bone cement injection to enhance fixation strength in severely osteoporotic spines. However, the screws commonly fracture during insertion. This study aims to evaluate how different positions/designs of radial holes may affect the pullout and structural strength of cannulated pedicle screws using finite element analysis. Three different screw hole designs were evaluated under torsion and bending conditions. The pullout strength for each screw was determined by axial pullout failure testing. The results showed that when the Von Mises stress reached the yield stress of titanium alloy the screw with four radial holes required a greater torque or bending moment than the nine and twelve hole screws. In the pullout test, the strength and stiffness of each screw with cement augmentation showed no significant differences, but the screw with four radial holes had a greater average pullout strength, which probably resulted from the significantly greater mean maximum lengths of cement augmentation. Superior biomechanical responses, with lower stress around the radial holes and greater pullout strength, represented by cannulated pedicle screw with four radial holes may worth recommending for clinical application. PMID:26054806

  18. Ball Screw Actuator Including a Compliant Ball Screw Stop

    Science.gov (United States)

    Wingett, Paul T. (Inventor); Hanlon, Casey (Inventor)

    2015-01-01

    An actuator includes a ball nut, a ball screw, and a ball screw stop. The ball nut is adapted to receive an input torque and in response rotates and supplies a drive force. The ball screw extends through the ball nut and has a first end and a second end. The ball screw receives the drive force from the ball nut and in response selectively translates between a retract position and a extend position. The ball screw stop is mounted on the ball screw proximate the first end to translate therewith. The ball screw stop engages the ball nut when the ball screw is in the extend position, translates, with compliance, a predetermined distance toward the first end upon engaging the ball nut, and prevents further rotation of the ball screw upon translating the predetermined distance.

  19. Minimally Invasive Pedicle Screw Fixation Combined with Vertebroplasty with Calcium Phosphate Bone Cement in the Treatment of Thoracolumbar Burst Fracture%微创椎弓根钉内固定联合磷酸钙骨水泥椎体成形术治疗胸腰椎爆裂性骨折

    Institute of Scientific and Technical Information of China (English)

    顾宇彤; 梁朝革; 张亮; 林红; 周健

    2015-01-01

    目的:评估微创椎弓根钉内固定(微小切口非空心椎弓根钉技术)联合磷酸钙骨水泥经皮穿刺椎体成形术(percutaneous vertebroplasty ,PVP)治疗胸腰椎爆裂性骨折的疗性和安全性。方法:采用微创椎弓根钉内固定联合磷酸钙骨水泥 PVP术治疗23例单节段胸腰椎新鲜爆裂性骨折且无神经症状的患者,伤椎位于 T11~L2,均属A3型骨折。记录手术时间、术中出血量、骨水泥注射量和住院天数。记录术前及术后即刻、1个月、2个月、3个月、6个月、1年、2年的腰背痛评分,计算并比较各时点的椎体高度压缩率、恢复率、椎体后凸角、椎体后凸矫正率。结果:磷酸钙骨水泥平均注射量为4.9(3.8~6.4)mL,平均手术时间92(75~120) min ,平均出血量52(40~75) mL ,平均住院5.6(4~7) d ,术后平均随访26(24~29)个月。VAS评分由术前的(8.8±1.2)分下降至术后即刻的(1.8±0.6)分及术后2年的(0.4±0.5)分,差异均有显著统计学意义(P<0.001)。高度压缩率由术前的(50.4±7.2)%显著下降至术后即刻的(6.2±1.5)%及术后2年的(6.9±1.4)%,差异均有显著统计学意义(P<0.001)。后凸角由术前的(22.6±1.8)°下降至术后即刻的(3.2±1.7)°及术后2年的(5.1±1.5)°,差异均有显著统计学意义( P<0.001)。随访过程中术后高度恢复率、后凸矫正率无明显减小;未出现螺钉松动、断钉或断棒。结论:微创椎弓根钉内固定联合磷酸钙骨水泥PV P术是治疗胸腰椎爆裂性骨折的安全、有效的方法。%Objective:To evaluate the efficacy and safety of minimally invasive pedicle screw fixation combined with percutaneous vertebroplasty(PVP) with calcium phosphate bone cement in the treatment of acute thoracolumbar burst fracture . Methods:Twenty‐three patients

  20. Novel anterior cruciate ligament graft fixation device reduces slippage

    Directory of Open Access Journals (Sweden)

    Lopez MJ

    2013-05-01

    Full Text Available Mandi J Lopez,1 Allen Borne,2 W Todd Monroe,3 Prakash Bommala,1 Laura Kelly,1 Nan Zhang11Laboratory for Equine and Comparative Orthopedic Research, Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, 2Louisiana State University, New Orleans Health Sciences Center, School of Medicine, New Orleans, 3Department of Biological and Agricultural Engineering, Agricultural Center, Louisiana State University, Baton Rouge, LA, USAAbstract: Clinically significant laxity occurs in 10%–30% of knees after anterior cruciate ligament reconstruction. Graft slippage and tension loss at the hamstring graft tibial fixation site during and after reconstruction surgery contribute to postoperative joint laxity and are detrimental to long-term knee stability and graft properties. Limiting graft slippage will reduce associated complications. We sought to compare the in vitro mechanical properties and in vivo joint stabilization, postoperative limb use, and graft incorporation of the novel GraftGrab™ (GG device designed to reduce hamstring graft tibial fixation slippage with the commercially available bioabsorbable Bio-Post™ and spiked washer (BP. Mechanical testing was performed on canine tibia-hamstring graft constructs to quantify initial fixation properties. In vivo joint stabilization, postoperative limb use and graft incorporation of hamstring graft reconstructions were determined in a canine model. Outcomes included tibial translation and ground reaction forces preoperatively and 4 and 8 weeks postoperatively, three-dimensional graft and bone tunnel dimensions at the latter two time points, and graft-bone microstructure, as well as mechanical properties 8 weeks after implantation. Immediately after fixation, all grafts slipped from the BP constructs versus about 30% of GG constructs. In vivo limb use remained low, and tibial translation increased with time in the BP cohort. These results together

  1. 经皮后路椎弓根螺钉固定治疗脊柱胸腰段骨折的临床效果%Clinical effect of percutaneous posterior pedicle screw fixation in the treatment of thoracolumbar fracture of spine

    Institute of Scientific and Technical Information of China (English)

    顾云峰

    2015-01-01

    目的:探讨经皮后路椎弓根螺钉固定治疗脊柱胸腰段骨折的临床效果。方法随机抽选2012年10月~2014年8月在我院骨科进行手术治疗的72例脊柱胸腰段骨折患者,将其根据抽签法氛围对照组、观察组,各36例。对照组采用开放椎弓根螺钉固定法进行治疗,观察组采用经皮后路椎弓根螺钉固定法进行治疗。比较两组的临床效果。结果观察组患者的手术切口长度明显短于对照组,术中出血量、术后引流量明显少于对照组,止痛针使用时间、住院时间明显短于对照组(P0.05);the two groups had no serious complication,the incidence rate of complication was 0. Conclusion Percu-taneous posterior pedicle screw fixation in the treatment of thoracolumbar fracture of spine has advantages of small wound,slight pain,quick recovery,great effect,and few complication.Therefore,as a clinical therapeutic method,it is scien-tific,effective,ideal,and safe.

  2. 带缝匠肌骨瓣移植联合空心钉内固定治疗青少年股骨颈骨折的临床效果分析%Clinical effect analysis of sartorial-pedicled ilium bone transplantation combined with hollow screw fixation treating femoral neck fracture of youngsters

    Institute of Scientific and Technical Information of China (English)

    郑凌云; 邓秋平; 田华强; 方良韬

    2015-01-01

    目的:分析带缝匠肌骨瓣移植联合空心钉内固定对青少年股骨颈骨折的治疗效果。方法选取本院2012年7月~2014年6月收治的80例青少年股骨颈骨折患者,按随机数字表法分成研究组和对照组,各40例。研究组采用带缝匠肌骨瓣移植术联合空心钉内固定术进行治疗;对照组单纯采用空心螺钉内固定术进行治疗。比较两组手术时间、术中出血量、住院时间、股骨头缺血性坏死发生率、骨折愈合时间、临床疗效及治疗前、后生活质量。结果研究组手术时间长于对照组(P0.05);研究组股骨头缺血性坏死发生率低于对照组(P0.05);研究组治疗后生活质量得分高于对照组(P0.05). The life quality score of research group after treatment was higher than that of control group (P<0.05). Conclusion Sartorial-pedicled ilium bone transplantation combined with hollow screw fixation treating femoral neck fracture of youngsters has the advantages of rapid recovery and good efficacy.

  3. Fixation of distal radius fractures in adults: a review.

    Science.gov (United States)

    Obert, L; Rey, P-B; Uhring, J; Gasse, N; Rochet, S; Lepage, D; Serre, A; Garbuio, P

    2013-04-01

    In patients for whom function is a priority, anatomic reduction and stable fixation are prerequisites for good outcomes. Several therapeutic options exist, including orthopedic treatment and internal fixation with pins (intra- and extrafocal), external fixation which may or may not bridge the wrist, and different internal fixation techniques with dorsal or palmar plates using or not, locking screws. Arthroscopy may be necessary in case of articular fracture. In the presence of significant metaphyseal bone defects, filling of the comminution with phosphocalcic cements provides better graft stability. The level of evidence is too low to allow recommending one type of fixation for one type of fracture; and different fixation options to achieve stable reduction exist, each with its own specific complications. With the new generations of palmar plate, secondary displacement is becoming a thing of the past. PMID:23518070

  4. The archimedes screw

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    On May 5, 2011, the Ontario Waterpower Association hosted the emergent hydro workshop in Peterborough. In the course of this workshop, GreenBug Energy Inc. presented the archimedes screw. This system consists of a screw turning under the weight of water falling, the screw turns the gear box and the generator, leading to the production of electricity. This technology can be used in 1 to 10 meter heads and can produce between 1 and 100 kW. The archimedes screw does not affect the passage of fish nor the water level, quantity or quality. There are thousands of low head sites across Canada in which the archimedes screw could be used to produce renewable electricity. However, the uncertainty of its being approved is an important issue as the industry cannot invest thousands of dollars in projects that might not be approved. This presentation showed that the archimedes screw could be a solution for producing electricity from low head sites but that some code analogous to the building code is required to minimize the uncertainty of approval.

  5. 单侧椎弓根螺钉固定经椎间孔腰椎体间融合治疗腰椎间盘突出症疗效分析%The effect analysis of transforamen lumbar interbody fusion in treatment of lumbar intervertebral disk herniation with unilateral pedicle screw fixation

    Institute of Scientific and Technical Information of China (English)

    李光富; 刘文斌; 罗政; 周焱涛

    2015-01-01

    Objective To explore the effect of transforamen lumbar interbody fusion in treatment of lumbar intervertebral disk herniation with unilateral pedicle screw fixation. Methods Retrospectivly studied the clinical data of 36 patients with lumbar intervertebral disk herniation who were treated through transforamen lumbar interbody fusion with unilateral pedicle screw from January 2011 to October 2012. There were 22 male and 14 female patients, aged form 44 to 68 years old with mean age of 56. The lesion positions included 8 patients in L3/4, 17 patients in L4/5, and 11 patients in L5/S1. The data of operation time, intraoperative bleeding volume, and postoperative drainage volume were collected. Therapeutic effect were evaluated by visual analogue score (VAS), lumbar vertebral score of Japanese Orthopedic Association (JOA) score, and Oswestry dysfunction index (ODI). Results Operation time was 65-100 min with mean time of 85 min. Intraoperative bleeding volume was 100-250 ml with mean volume of 135 ml. Postoperative drainage volume was 100-200 ml with mean volume of 150 ml. Followed up for 12-36 months with mean time of 20 months. No loosening, breakage of screws or displacement of interbody fusion cages were found in the follow up period. The rate of anastomosis was 100%(36/36). The VAS was (7.9 ± 1.2) scores before operation and (1.1±0.3) scores at the end of follow up period, there was significant difference( P<0.05). The JOA score was (10.2±2.6) scores before operation and (23.2±4.3) scores at the end of follow up period, there was significant difference (P<0.05). The ODI was (43.3±6.2) scores before operation and (15.2±4.3) scores at the end of follow up period, there was significant difference ( P<0.05). Conclusion The effect of transforamen lumbar interbody fusion with unilateral pedicle screw fixation is proper for the patients who are suffering from lumbar intervertebral disk herniation, which has advantages of less invasion, less bleeding, better

  6. Iso-C臂三维导航系统指导下的脊柱侧弯椎弓根钉内固定:问题与优势%Pedicle screw fixation for scoliosis using Iso-C arm three-dimensional navigation:problems and advantages

    Institute of Scientific and Technical Information of China (English)

    陈强; 张怡元; 林妙阔; 冯尔宥

    2015-01-01

    背景:由于脊柱侧弯患者脊柱解剖结构的变异、椎体旋转、椎体缺如、椎管变形等异常情况,椎弓根螺钉一旦置入发生偏差,即可导致灾难性结果。近年来随着椎弓根螺钉的广泛应用和计算机导航的不断发展,使脊柱侧弯修复手术更加精确、安全。  目的:综述Iso-C臂三维导航系统指导脊柱侧弯椎弓根钉置入内固定存在的问题及优势。  方法:由第一作者检索至2012年12月为止 PubMed数据(http://www.ncbi.nlm.nih.gov/PubMed)及CNKI中国期刊全文数据库(http://www.cnki.net/),以“计算机导航,脊柱侧弯,椎弓根钉”为检索词,检索摘要内同时包含上述检索词的文献。共检索到50多篇相关文献,13篇文献符合纳入标准。  结果与结论:应用 Iso-C 臂三维导航系统进行脊柱侧弯椎弓根螺钉置入内固定具有显著优势。它充分结合了CT三维导航和术中透视导航的优点,可快速、准确的采集术中影像数据,通过影像实时显示,从而确保修复手术的安全。Iso-C臂三维导航其自动注册的功能无疑提高了修复效率和精确性,帮助术者以更加精确、安全的方式进行各种复杂的脊柱侧弯修复手术。%BACKGROUND:Due to variation of spinal anatomic structure, vertebral body rotation, absence of vertebral body, and spinal canal deformation in patients with scoliosis, the deviation of pedicle screw placement can induce catastrophic results. Recently, with the wide application of pedicle screw and the continuous development of computer navigation, scoliosis surgery becomes more accurate and safe. OBJECTIVE:To review the existing problems and advantages of Iso-C arm three-dimensional (3D) navigation system for guiding internal fixation of pedicle screw implantation in the treatment of scoliosis. METHODS: The first author searched PubMed (http://www.ncbi.nlm.nih.gov/PubMed) and CNKI (http

  7. Treatment of canal tumors of the upper cervical spine by posterior laminectomy and fixation screw rod system%后路椎板切除、钉棒系统内固定治疗上颈椎椎管内肿瘤

    Institute of Scientific and Technical Information of China (English)

    林斌; 王宗江; 丁真奇; 刘晖; 郭志民; 陈长青; 郭林新

    2009-01-01

    Objective To investigate the methods and curative effects of posterior laminectomy and fixation screw rod system in treatment of canal tumors of the upper cervical spine. Methods Between Jan-uary 2003 and June 2008, 16 patients (10 males and 6 females, average age 44.7 years, range 33-68 years) with canal tumor of the upper cervical spine were treated, including epidural neoplasms in 2 cases, intradu-ral extramedullary tumors in 13, and intramedullary tumor in 1 case. The tumors were located between medulla oblongata and C1 in 3 cases, C1,2 in 8, C2 in 2, C1-3 in 2, C2,3 in 1; 4 cases were located at ventralis of cervical cord. Spinal cord was pressed by tissue of tumor in fifteen patients which were diagnosed by MRI and computerized tomographic (CT) scans. According to the Frankel grading system, there was C in 5 cases, D in 10 cases, E in 1 case. They were treated by posterior approach to remove of tumors after laminectomy, fixation with pedicle screw rod system and fusion with autogenous bone grafts. Results The follow-up was obtained for 6-58 months(mean 27.4 months). According to the JOA grading system, the preoperative average score was 8.8, 16 at 6 months postoperatively, and the average improvement rate was 88.1%. According to the Frankel grading system, 7 cases improved from D to E, 5 from C to D, but none in 3 cases with Frankel D and 1 with E. The good fusion of bone graft was found in iconography examination. Conclusion The treatment by posterior approach to remove of tumors after laminectomy, and fixation with pedicle screw sys-tem and fusion with autogenous bone grafts, can relive compression of cervical cord, nerve root, remove of tu-mor lesion thoroughly, reconstruct stabilization of the upper cervical spine and improve life quality of pa-tients.%目的 探讨后路椎板切除、钉棒系统内固定及自体髂骨植骨融合术治疗上颈椎椎管内肿瘤的方法及疗效.方法 2003年1月至2008年6月,共收治

  8. Posterior vertebral column resections combined with titanium screw rod fixation for the treatment of severe spinal deformity%后路椎体环截及钛合金钉棒内固定治疗重度脊柱畸形

    Institute of Scientific and Technical Information of China (English)

    卡哈尔•艾肯木; 楚戈; 黄佳; 高琪乐; 吴加文; 林旻中

    2013-01-01

    BACKGROUND:Vertebral column resection is the frequently mentioned spinal orthopaedic concept. Due to the high requirement of the operation skil , difficulty and more complications, the previous studies have reported from different aspects, and many researchers have focused on the analysis of complications, that may be related with the procedure and manner. OBJECTIVE:To analyze the efficacy and complications of posterior vertebral column resection combined with titanium screw rod fixation for the treatment of severe spinal deformity. METHODS:We retrospectively analyzed 48 patients with severe spinal deformity who treated with posterior vertebral column resection and titanium screw rod fixation, with an average removal of 1.6 vertebral. The patients were fol owed-up for 15-64 months. The Cobb angle (coronal plane and sagittal plane) of the patients before treatment, after treatment and in the final fol ow-up was analyzed, and the relative complications of the surgery were analyzed. RESULTS AND CONCLUSION:The patients with spinal deformity were divided into five categories, included kyphoscoliosis (n=11), severe scoliosis (n=20), congenital spinal deformity (n=4), spherical kyphosis (n=3), and angular kyphosis (n=10). The average coronal plane deformity angle of the patients was corrected from 84° preoperation to 35° postoperation, with the total correction rate of 54%. The average sagittal plane deformity angle was corrected from 90° preoperation to 42° postoperation, and the sagittal plane Cobb angle was decreased for 48°. The mean operation time was 545 minutes (204-1 355 minutes), the intraoperative blood loss was 1 610 mL (50-8 244 mL), and the average blood loss was 65%. After treatment, 31 cases had complications, including 13 cases of intraoperative neurological dysfunction (observed through electrophysiological monitoring and wake), permanent neurological dysfunction did not occur after timely treatment. The posterior vertebral column resection and

  9. Bone Cement Augmentation of Pedicle Screw Fixation Combined with Kyphoplasty for Osteoporotic Thoracolumbar Burst Fractures%骨水泥强化椎弓根螺钉固定结合椎体后凸成形术治疗骨质疏松性胸腰段爆裂骨折

    Institute of Scientific and Technical Information of China (English)

    于亮; 蒋伟宇; 赵刘军; 马维虎; 徐荣明

    2014-01-01

    [目的]评估骨水泥强化椎弓根螺钉固定结合椎体后凸成形术(percutaneous kyphoplasty,PKP)治疗骨质疏松性胸腰椎爆裂骨折的临床疗效。[方法]收集本院2011年1月至2012年12月采用骨水泥强化椎弓根螺钉固定结合PKP治疗的31例无神经损伤的骨质疏松性胸腰椎爆裂骨折患者,观测术前、术后1周及术后1年伤椎前后缘压缩率改变、后凸Cobb角、视觉模拟评分(visual analogue scale,VAS)及术后并发症,评估手术效果。[结果]术前椎体前、后缘压缩率分别为(49.5±6.1)%和(16.7±3.2)%,术后1年椎体前后缘压缩率分别为(9.1±1.3)%和(1.2±0.9)%,Cobb角由术前平均(25.7±4.5)°矫正至术后(3.3±2.1)°,平均矫正19.8°,VAS评分由术前平均(7.2±0.5)分降为术后(1.9±0.6)分,各项指标术后与术前比较差异均有统计学意义(P<0.05)。术后随访12~24个月,无1例发生手术并发症。[结论]骨水泥强化椎弓根螺钉固定结合PKP治疗骨质疏松性胸腰椎爆裂骨折,能有效恢复脊柱矢状序列,同时也能较好地维持伤椎的高度和强度,避免术后椎体塌陷,有助于早期康复,减少并发症。%Objective] To assess the efficacy of bone cement augmentation of pedicle screw fixation combined with kyphoplasty for osteoporotic thoracolumbar burst fractures. [Methods] Thirty-one cases of neurological y intact osteoporotic thoracolumbar burst fractures treated by bone cement augmentation of pedicle screw fixation combined with kyphoplasty between January 2011 and December 2012 were included in this study. Then analyze the front and back edges height of the injured vertebra, kyphosis Cobb ’s angle, visual analogue scale(VAS) and complications. [Results] Patients were fol owed up for 12 to 24 months(mean 18.2 months), there was no complication. Al patients recovered satisying, front and back edges of the compression ratio was (49.5±6.1)%and

  10. 选择性椎间融合与椎弓根螺钉置入修复退变性腰椎侧凸:脊柱稳定性评价%Selective interbody fusion combined with pedicle screw fixation for degenerative lumbar scoliosis:spinal stability

    Institute of Scientific and Technical Information of China (English)

    尹承慧; 符臣学; 叶永平; 徐皓

    2015-01-01

    fusion should be conducted. This can achieve nerve decompression, spinal stability, and is relatively minimaly invasive. OBJECTIVE:To explore the efficacy of selective interbody fusion, limited neural decompression combined with pedicle screw system fixation for degenerative lumbar scoliosis. METHODS:Clinical characteristics of 53 patients with degenerative lumbar scoliosis were retrospectively analyzed, and the indication and contraindication were investigated. Selective interbody fusion, and limited neural decompression combined with pedicle screw system fixation were performed in the patients. Treatment effect and complication were analyzed. During folow-up, Suk standard was utilized to judge bone graft fusion. Before treatment and during final folow-up, lower back pain score system recommended by the Japanese Orthopaedic Association was used for assessment, and the excelent and good rate of curative effects was calculated. Cobb’s angle on the sagittal and coronal positions was compared and analyzed before and after treatment. RESULTS AND CONCLUSION:The patients were folowed up for 12 to 36 months. According to low back pain score of Japanese Orthopaedic Association Scores, the excelent and good rate of curative effect was 89% during the last folow-up. According to Suk standard, the fusion rate of vertebra was 94%. The last X-ray films revealed that Cobb’s angle was averagely (4.3±2.3)° (0°-13.5°) on the coronal plane after treatment, and the correction rate of scoliosis was 56%. The Cobb’s angle was averagely (45.1±12.5)° (10.4°-65.3°) after treatment, and the correction rate of lordosis was 36%. Complications after repair consisted of cerebrospinal fluid leakage in two cases, nerve injury in two cases, instrumental failure in one case, and pulmonary infection in one case, and symptomatic deep venous thrombosis in three cases. These findings suggest that selective interbody fusion, and limited neural decompression combined with pedicle screw system

  11. ADOLESCENT IDIOPATHIC SCOLIOSIS: EVALUATION ON THE EFFECT OF SCREW DENSITY IN THE CORRECTION

    Directory of Open Access Journals (Sweden)

    Enguer Beraldo Garcia

    2016-03-01

    Full Text Available ABSTRACT Objective: The objective was to investigate implant density or the number of screws correlated with the correction of the main curve in patients undergoing surgery for adolescent idiopathic scoliosis (AIS. Methods: We evaluated 112 medical records: 33 patients with screw density of up to 50%, and 79 patients with a density of 100%; all patients underwent surgical correction by posterior approach with transpedicular fixation. Results: In the group of patients with screw density of up to 50% the residual Cobb median was 10°; in the group with 100% density, the median was 7°. Conclusion: Biostatistical analysis showed that the group with up to 50% of screw density presented correction rate of 82.1% and the group with 100% density had correction of about 86.8%. It is therefore concluded that the difference is statistically significant in favor of the fixation with 100% density (p =0.010.

  12. Intra-operative computer navigation guided cervical pedicle screw insertion in thirty-three complex cervical spine deformities

    Directory of Open Access Journals (Sweden)

    S Rajasekaran

    2010-01-01

    Full Text Available Background: Cervical pedicle screw fixation is challenging due to the small osseous morphometrics and the close proximity of neurovascular elements. Computer navigation has been reported to improve the accuracy of pedicle screw placement. There are very few studies assessing its efficacy in the presence of deformity. Also cervical pedicle screw insertion in children has not been described before. We evaluated the safety and accuracy of Iso-C 3D-navigated pedicle screws in the deformed cervical spine. Materials and Methods: Thirty-three patients including 15 children formed the study group. One hundred and forty-five cervical pedicle screws were inserted using Iso-C 3D-based computer navigation in patients undergoing cervical spine stabilization for craniovertebral junction anomalies, cervico-thoracic deformities and cervical instabilities due to trauma, post-surgery and degenerative disorders. The accuracy and containment of screw placement was assessed from postoperative computerized tomography scans. Results: One hundred and thirty (89.7% screws were well contained inside the pedicles. Nine (6.1% Type A and six (4.2% Type B pedicle breaches were observed. In 136 levels, the screws were inserted in the classical description of pedicle screw application and in nine deformed vertebra, the screws were inserted in a non-classical fashion, taking purchase of the best bone stock. None of them had a critical breach. No patient had any neurovascular complications. Conclusion: Iso-C navigation improves the safety and accuracy of pedicle screw insertion and is not only successful in achieving secure pedicle fixation but also in identifying the best available bone stock for three-column bone fixation in altered anatomy. The advantages conferred by cervical pedicle screws can be extended to the pediatric population also.

  13. A new alternative to expandable pedicle screws: Expandable poly-ether-ether-ketone shell.

    Science.gov (United States)

    Demir, Teyfik

    2015-05-01

    Screw pullout is a very common problem in the fixation of sacrum with pedicle screws. The principal cause of this problem is that the cyclic micro motions in the fixation of sacrum are higher than the other regions of the vertebrae that limit the osteo-integration between bone and screw. In addition to that, the bone quality is very poor at sacrum region. This study investigated a possible solution to the pullout problem without the expandable screws' handicaps. Newly designed poly-ether-ether-ketone expandable shell and classical pedicle screws were biomechanically compared. Torsion test, pullout tests, fatigue tests, flexion/extension moment test, axial gripping capacity tests and torsional gripping capacity tests were conducted in accordance with ASTM F543, F1798 and F1717. Standard polyurethane foam and calf vertebrae were used as embedding medium for pullout tests. Classical pedicle screw pullout load on polyurethane foam was 564.8 N compared to the failure load for calf vertebrae's 1264 N. Under the same test conditions, expandable poly-ether-ether-ketone shell system's pullout loads from polyurethane foam and calf vertebrae were 1196.3 and 1890 N, respectively. The pullout values for expandable poly-ether-ether-ketone shell were 33% and 53% higher than classical pedicle screw on polyurethane foam and calf vertebrae, respectively. The expandable poly-ether-ether-ketone shell exhibited endurance on its 90% of yield load. Contrary to poly-ether-ether-ketone shell, classical pedicle screw exhibited endurance on 70% of its yield load. Expandable poly-ether-ether-ketone shell exhibited much higher pullout performance than classical pedicle screw. Fatigue performance of expandable poly-ether-ether-ketone shell is also higher than classical pedicle screw due to damping the micro motion capacity of the poly-ether-ether-ketone. Expandable poly-ether-ether-ketone shell is a safe alternative to all other expandable pedicle screw systems on mechanical perspective

  14. Tightening force and torque of nonlocking screws in a reverse shoulder prosthesis

    OpenAIRE

    Terrier, Alexandre; Kochbeck, Stephanie; Merlini, Francesco; Gortchacow, Miguel; Pioletti, Dominique P; Farron, Alain

    2010-01-01

    Background. Reversed shoulder arthroplasty is an accepted treatment for glenohumeral arthritis associated to rotator cuff deficiency. For most reversed shoulder prostheses, the baseplate of the glenoid component is uncemented and its primary stability is provided by a central peg and peripheral screws. Because of the importance of the primary stability for a good osteo-integration of the baseplate, the optimal fixation of the screws is crucial. In particular, the amplitude of the tightening f...

  15. Surface polishing positively influences ease of plate and screw removal

    Directory of Open Access Journals (Sweden)

    JS Hayes

    2010-02-01

    Full Text Available Difficulties removing temporary fracture fixation devices due to excessive bony on-growth results in extended surgical time leading to excessive blood loss, debris contamination and potentially refracture. Commercially available locking plates and screws are manufactured for clinics with a micro-rough surface, which contributes to the excessive bony on-growth reported. We have applied polishing technology to commercially pure titanium locking compression plates (LCP and titanium-6%aluminium-7%niobium (TAN plates and screws to assess if it can alleviate problems with strong bony overgrowth. Samples were implanted for 6, 12 and 18 months in a bilateral sheep tibia non fracture model and assessed for screw removal torque, percentage of bone contact and tissue-material response. Both electropolishing (p=0.001 and paste polishing (p=0.010 of TAN screws significantly reduced the mean torque required for removal compared to their micro-rough counterparts. This was accompanied by a trend for a lower percentage of bone contact for polished screws. This difference in bone contact was significant for paste polished TAN screws (p<0.001 but not electropolished TAN screws (p=0.066. Ex vivo, soft tissue removal was much easier (~five minutes for polished constructs, which was difficult and at least four times longer for standard micro-rough constructs. We suggest that polishing of locked plate/screw systems will improve ease of removal and reduce implant related removal complications encountered due to excessive strong bony on-growth while maintaining biocompatibility and implant stability. Future studies aim to assess the potential of this technology in the next level of complication, a fracture model.

  16. 椎间打压植骨联合棘突椎板复合体回植内固定治疗退变性腰椎不稳症%LUMBAR INTERBODY FUSION IMPACTED BONE GRAFTS COMBINED WITH REGRAFTING IN SITU WITH SPINOUS PROCESS AND VERTEBRAL PLATE COMPLEX AND PEDICLE SCREW FIXATION FOR LUMBAR DEGENERATIVE INSTABILITY

    Institute of Scientific and Technical Information of China (English)

    张超远; 孟祥翔; 秦晓彬; 付玉娟; 付鹏军

    2012-01-01

    Objective To evaluate the effectiveness of lumbar interbody fusion impacted bone grafts combined with regrafting in situ with spinous process and vertebral plate complex and pedicle screw fixation for lumbar degenerative instability. Methods Between January 1998 and October 2010, 48 patients with lumbar degenerative instability were treated by posterior decompression, lumbar interbody fusion impacted bone grafts combined with regrafting in situ with spinous process and vertebral plate complex and pedicle screw fixation. There were 26 males and 22 females, aged 52-76 years (mean, 62.4 years). The disease duration was 7 months to 25 years (mean, 6.5 years). One segmental instability was located at L3,4 in 1 case, at L4,5 in 10 cases, and at L5, S1 in 11 cases; multi-segmental instability was located at L3,4, L4,5, and L5, S1 in 5 cases, at L2,3 and L3,4 in 2 cases, at L3,4 and L4,5 in 10 cases, and at L4,5 and L5, S1 in 9 cases. Of 48 patients, 32 complicated by lumbar disc herniation, 46 by lumbar spinal stenosis, and 16 by degenerative scoliosis. The clinical results were evaluated by the Japanese Orthopaedic Association (JOA) score, recovery rate, disc height, and lumbar lordosis angles. Results The incisions obtained healing by first intention after operation. No nerve injury, rod or screw breakage, and infection occurred during and after operation. All 48 patients were followed up 1 to 6 years. The fusion time was 12-18 weeks (mean, 16.2 weeks). Vertebra slipping or degenerative scoliosis was corrected, and spinal column series became normal. At preoperation, 6 months after operation, and last follow-up, the disc heights were (5.2 ± 2.3), (11.9 ± 2.0), and (11.6 + 2.1) mm, respectively; the JOA scores were 3.2 + 2.1, 12.8 ± 1.6, and 13.6 + 1.2, respectively; and the lumbar lordosis angles were (-20.5 ± 10.5), (30.5 ± 8.5), and (31.2 + 5.6)°, respectively. The JOA scores, disc heights, and lumbar lordosis angles were significantly improved at 6 months after

  17. Instrumental design for anterior fixation of dorsal and lumbar spine

    International Nuclear Information System (INIS)

    This is an experimental work; the main purpose is design a system for anterior fixation of thoracolumbar spine. The system includes screws, rods and transverse connectors. Mechanical tests to the system with axial and rotation charges showed elevated resistance and plasticity. The process include the development of elements for application of the system

  18. 上颈椎3D打印模型的精确性验证及在前路枕-寰-枢螺钉内固定术中的可行性%3D-printed upper cervical models: accuracy validation and feasibility study into anterior occiput-to-axis screw fixation on them

    Institute of Scientific and Technical Information of China (English)

    吴爱悯; 金海明; 车灿文; 吴立军; 林仲可; 倪文飞; 徐华梓; 池永龙; 王向阳

    2016-01-01

    Objective To validate the accuracy of 3D-printed upper cervical models and investigate the feasibility of use of the models in anterior occiput-to-axis screw fixation, in an attempt to provide a protocol of pre-operative plan for surgeons.Methods Forty-five adult atlantoaxial CT scans were obtained, imported into Mimics software for 3 D reconstruction, successively imported into 3 D printer to print the 3D models.Fourteen parameters were measured on both imaging system and 3D-printed models to validate the accuracy of 3D-printed models.Thirty upper cervical CT data were obtained and imported into Mimics software for 3D reconstruction.Cylinders in 1.75 mm radius were drawn to simulate the trajectory of anterior occiput-to-axis screw fixation.Anteroposterior view of the minimum lateral angle (α1) and maximum lateral angle (α2) and lateral view of the minimum posterior angle (β1) and maximum posterior angle (β2) were measured.Mean value of α1 and α2 was calculated as α3 and mean value of β1 and β2 as β3.Meanwhile, the 3D models were printed, and an angle guide device was used to introduce the anterior occiput-to-axis screws into the 3D models in reference to the angles of α3 and β3.Anteroposterior view of lateral angle (α4) and lateral view of posterior angle (β4) were measured.Differences in α3 vs.α4 and β3 vs.β4 were compared.Results All above 14 parameters did not differ significantly between radiographic images and 3D-printed models (P > 0.05).Intraclass correlation coefficient (ICC) values of 13 parameters were > 0.800.On the 3D digital models, the α3 was (12.6 ± 3.7) ° (left) and (12.0 ±4.2) ° (right), and the β3 was (23.9 ± 4.8) ° (left) and (23.4 ± 4.9) ° (right).On the 3 D-printed models, the α4 was (12.0 ± 4.1) ° (left) and (12.3 ± 4.1) ° (right), and β4 was (23.4 ± 4.2) ° (left) and (22.8 ± 4.4)° (right).There were no significant differences in both comparisons of α3 vs.α4 and β3 vs.β4 (P > 0.05).Conclusions

  19. Surface polishing positively influences ease of plate and screw removal

    OpenAIRE

    JS Hayes; U Seidenglanz; AI Pearce; SG Pearce; CW Archer; RG Richards

    2010-01-01

    Difficulties removing temporary fracture fixation devices due to excessive bony on-growth results in extended surgical time leading to excessive blood loss, debris contamination and potentially refracture. Commercially available locking plates and screws are manufactured for clinics with a micro-rough surface, which contributes to the excessive bony on-growth reported. We have applied polishing technology to commercially pure titanium locking compression plates (LCP) and titanium-6%aluminium-...

  20. Comparison of the bending performance of solid and cannulated spinal pedicle screws using finite element analyses and biomechanical tests.

    Science.gov (United States)

    Shih, Kao-Shang; Hsu, Ching-Chi; Hou, Sheng-Mou; Yu, Shan-Chuen; Liaw, Chen-Kun

    2015-09-01

    Spinal pedicle screw fixations have been used extensively to treat fracture, tumor, infection, or degeneration of the spine. Cannulated spinal pedicle screws with bone cement augmentation might be a useful method to ameliorate screw loosening. However, cannulated spinal pedicle screws might also increase the risk of screw breakage. Thus, the purpose of this study was to investigate the bending performance of different spinal pedicle screws with either solid design or cannulated design. Three-dimensional finite element models, which consisted of the spinal pedicle screw and the screw's hosting material, were first constructed. Next, monotonic and cyclic cantilever bending tests were both applied to validate the results of the finite element analyses. Finally, both the numerical and experimental approaches were evaluated and compared. The results indicated that the cylindrical spinal pedicle screws with a cannulated design had significantly poorer bending performance. In addition, conical spinal pedicle screws maintained the original bending performance, whether they were solid or of cannulated design. This study may provide useful recommendations to orthopedic surgeons before surgery, and it may also provide design rationales to biomechanical engineers during the development of spinal pedicle screws. PMID:26208430

  1. In vitro evaluation of various bioabsorbable and nonresorbable barrier membranes for guided tissue regeneration

    Directory of Open Access Journals (Sweden)

    Smeets Ralf

    2008-10-01

    Full Text Available Abstract Background Different types of bioabsorbable and nonresorbable membranes have been widely used for guided tissue regeneration (GTR with its ultimate goal of regenerating lost periodontal structures. The purpose of the present study was to evaluate the biological effects of various bioabsorbable and nonresorbable membranes in cultures of primary human gingival fibroblasts (HGF, periodontal ligament fibroblasts (PDLF and human osteoblast-like (HOB cells in vitro. Methods Three commercially available collagen membranes [TutoDent® (TD, Resodont® (RD and BioGide® (BG] as well as three nonresorbable polytetrafluoroethylene (PTFE membranes [ACE (AC, Cytoplast® (CT and TefGen-FD® (TG] were tested. Cells plated on culture dishes (CD served as positive controls. The effect of the barrier membranes on HGF, PDLF as well as HOB cells was assessed by the Alamar Blue fluorometric proliferation assay after 1, 2.5, 4, 24 and 48 h time periods. The structural and morphological properties of the membranes were evaluated by scanning electron microscopy (SEM. Results The results showed that of the six barriers tested, TD and RD demonstrated the highest rate of HGF proliferation at both earlier (1 h and later (48 h time periods (P P ≤ 0.001. In HOB cell culture, the highest rate of cell proliferation was also calculated for TD at all time periods (P Conclusion Results from the present study suggested that GTR membrane materials, per se, may influence cell proliferation in the process of periodontal tissue/bone regeneration. Among the six membranes examined, the bioabsorbable membranes demonstrated to be more suitable to stimulate cellular proliferation compared to nonresorbable PTFE membranes.

  2. Screw-Retaining Allen Wrench

    Science.gov (United States)

    Granett, D.

    1985-01-01

    Steadying screws with fingers unnecessary. Crimp in uncompressed spring wire slightly protrudes from one facet of Allen wrench. Compressed spring retains Allen screw. Tool used with Allen-head screws in cramped spaces with little or no room for fingers to hold fastener while turned by wrench.

  3. INFLUENCE OF SELF-TAPPING SCREW ELECTRO-ARC MACHINING ON ITS TWISTING-IN IN SPECIMENS MADE OF VARIOUS MATERIALS AND TWISTING-OUT PROCEDURE

    OpenAIRE

    M. G. Kiselev; A. V. Drozdov; S. G. Monich; P. S. Bogdan

    2015-01-01

    The paper provides an experimental evaluation pertaining to the influence of steel self-tapping screw on its twisting-in specimens made of various materials and its twisting-out process. Main principles of the investigation methodology including description of  technological scheme of self-tapping screw electro-arc machining and specimens applied while executing the experiments and hardware measuring tools used for fixation of torque which has been applied to the self-tapping screw during its...

  4. In vitro biomechanical study of pedicle screw pull-out strength based on different screw path preparation techniques

    Science.gov (United States)

    Moldavsky, Mark; Salloum, Kanaan; Bucklen, Brandon; Khalil, Saif; Mehta, Jwalant S

    2016-01-01

    Background: Poor screw-to-bone fixation is a clinical problem that can lead to screw loosening. Under-tapping (UT) the pedicle screw has been evaluated biomechanically in the past. The objective of the study was to determine if pedicle preparation with a sequential tapping technique will alter the screw-to-bone fixation strength using a stress relaxation testing loading protocol. Materials and Methods: Three thoracolumbar calf spines were instrumented with pedicle screws that were either probed, UT, standard-tapped (ST), or sequential tapped to prepare the pedicle screw track and a stress relaxation protocol was used to determine pull-out strength. The maximum torque required for pedicle screw insertion and pull-out strength was reported. A one-way ANOVA and Tukeys post-hoc test were used to determine statistical significance. Results: The pedicle screw insertion torques for the probed, UT, ST and sequentially tapped (SQT) techniques were 5.09 (±1.08) Nm, 5.39 (±1.61) Nm, 2.93 (±0.43) Nm, and 3.54 (±0.67) Nm, respectively. There is a significant difference between probed compared to ST (P ≤ 0.05), as well as UT compared to both ST and SQT (P ≤ 0.05). The pull-out strength for pedicle screws for the probed, UT, ST and SQT techniques was 2443 (±782) N, 2353(±918) N, 2474 (±521) N, and 2146 (±582) N, respectively, with no significant difference (P ≥ 0.05) between techniques. Conclusions: The ST technique resulted in the highest pull-out strength while the SQT technique resulted in the lowest. However, there was no significant difference in the pull-out strength for the various preparation techniques and there was no correlation between insertion torque and pull-out strength. This suggests that other factors such as bone density may have a greater influence on pull-out strength. PMID:27053808

  5. Strength analysis of clavicle fracture fixation devices and fixation techniques using finite element analysis with musculoskeletal force input.

    Science.gov (United States)

    Marie, Cronskär

    2015-08-01

    In the cases, when clavicle fractures are treated with a fixation plate, opinions are divided about the best position of the plate, type of plate and type of screw units. Results from biomechanical studies of clavicle fixation devices are contradictory, probably partly because of simplified and varying load cases used in different studies. The anatomy of the shoulder region is complex, which makes it difficult and expensive to perform realistic experimental tests; hence, reliable simulation is an important complement to experimental tests. In this study, a method for finite element simulations of stresses in the clavicle plate and bone is used, in which muscle and ligament force data are imported from a multibody musculoskeletal model. The stress distribution in two different commercial plates, superior and anterior plating position and fixation including using a lag screw in the fracture gap or not, was compared. Looking at the clavicle fixation from a mechanical point of view, the results indicate that it is a major benefit to use a lag screw to fixate the fracture. The anterior plating position resulted in lower stresses in the plate, and the anatomically shaped plate is more stress resistant and stable than a regular reconstruction plate. PMID:25850983

  6. A Novel Fixation System for Acetabular Quadrilateral Plate Fracture: A Comparative Biomechanical Study

    Directory of Open Access Journals (Sweden)

    Guo-Chun Zha

    2015-01-01

    Full Text Available This study aims to assess the biomechanical properties of a novel fixation system (named AFRIF and to compare it with other five different fixation techniques for quadrilateral plate fractures. This in vitro biomechanical experiment has shown that the multidirectional titanium fixation (MTF and pelvic brim long screws fixation (PBSF provided the strongest fixation for quadrilateral plate fracture; the better biomechanical performance of the AFRIF compared with the T-shaped plate fixation (TPF, L-shaped plate fixation (LPF, and H-shaped plate fixation (HPF; AFRIF gives reasonable stability of treatment for quadrilateral plate fracture and may offer a better solution for comminuted quadrilateral plate fractures or free floating medial wall fracture and be reliable in preventing protrusion of femoral head.

  7. Distal Locking Screws for Intramedullary Nailing of Tibial Fractures.

    Science.gov (United States)

    Agathangelidis, Filon; Petsatodis, Georgios; Kirkos, John; Papadopoulos, Pericles; Karataglis, Dimitrios; Christodoulou, Anastasios

    2016-01-01

    Recently introduced tibial intramedullary nails allow a number of distal screws to be used to reduce the incidence of malalignment and loss of fixation of distal metaphyseal fractures. However, the number of screws and the type of screw configuration to be used remains obscure. This biomechanical study was performed to address this question. Thirty-six Expert tibial nails (Synthes, Oberdorf, Switzerland) were introduced in composite bone models. The models were divided into 4 groups with different distal locking configurations ranging from 2 to 4 screws. A 7-mm gap osteotomy was performed 72 mm from the tibial plafond to simulate a 42-C3 unstable distal tibial fracture. Each group was divided in 3 subgroups and underwent nondestructive biomechanical testing in axial compression, coronal bending, and axial torsion. The passive construct stiffness was measured and statistically analyzed with one-way analysis of variance. Although some differences were noted between the stiffness of each group, these were not statistically significant in compression (P=.105), bending (P=.801), external rotation (P=.246), and internal rotation (P=.370). This in vitro study showed that, when using the Expert tibial nail for unstable distal tibial fractures, the classic configuration of 2 parallel distal screws could provide the necessary stability under partial weight-bearing conditions. PMID:26840700

  8. Treatment of scaphoid waist fractures with the HCS screw

    Directory of Open Access Journals (Sweden)

    Gehrmann, Sebastian V.

    2014-11-01

    Full Text Available The aim of the study was to evaluate the clinical results of the Headless Compression Screw (HCS, Synthes when used for treatment of acute scaphoid waist fractures. The new screw design generates interfragmentary compression with use of a compression sleeve. Twenty-one patients were treated for acute scaphoid waist fractures type B2 with HCS screws. The average time to the final follow-up examination was 12.8 months. All 21 fractures united after a mean time of 7.2 weeks. The mean DASH score was 7.1. The average motion of the wrist in extension was 61°, flexion was 46°, radial abduction reached 25° and the ulnar abduction was 31°. The maximally achieved grip strength was 86% compared to the uninjured side. Treatment of type B2 scaphoid fractures with the Headless Compression Screw showed good functional and radiographic results. The results are similar to those identified using other screw fixation systems.

  9. In vitro and in vivo studies on the degradation of high-purity Mg (99.99wt.%) screw with femoral intracondylar fractured rabbit model.

    Science.gov (United States)

    Han, Pei; Cheng, Pengfei; Zhang, Shaoxiang; Zhao, Changli; Ni, Jiahua; Zhang, Yuanzhuang; Zhong, Wanrun; Hou, Peng; Zhang, Xiaonong; Zheng, Yufeng; Chai, Yimin

    2015-09-01

    High-purity magnesium (HP Mg) takes advantage in no alloying toxic elements and slower degradation rate in lack of second phases and micro-galvanic corrosion. In this study, as rolled HP Mg was fabricated into screws and went through in vitro immersion tests, cytotoxicity test and bioactive analysis. The HP Mg screws performed uniform corrosion behavior in vitro, and its extraction promoted cell viability, bone alkaline phosphatase (ALP) activity, and mRNA expression of osteogenic differentiation related gene, i.e. ALP, osteopontin (OPN) and RUNX2 of human bone marrow mesenchymal stem cells (hBMSCs). Then HP Mg screws were implanted in vivo as load-bearing implant to fix bone fracture and subsequently gross observation, range of motion (ROM), X-ray scanning, qualitative micro-computed tomography (μCT) analysis, histological analysis, bending-force test and SEM morphology of retrieved screws were performed respectively at 4, 8, 16 and 24 weeks. As a result, the retrieved HP Mg screws in fixation of rabbit femoral intracondylar fracture showed uniform degradation morphology and enough bending force. However, part of PLLA screws was broken in bolt, although its screw thread was still intact. Good osseointegration was revealed surrounding HP Mg screws and increased bone volume and bone mineral density were detected at fracture gap, indicating the rigid fixation and enhanced fracture healing process provided by HP Mg screws. Consequently, the HP Mg showed great potential as internal fixation devices in intra-articular fracture operation. PMID:26117658

  10. Comparison of clinical efficacy of minimally invasive versus open transforaminal lumbar interbody fusion with unilat-eral pedicle screw fixation for lumbar disc herniation%单侧微创与开放经椎间孔腰椎椎体间融合内固定治疗腰椎椎间盘突出症的临床疗效比较

    Institute of Scientific and Technical Information of China (English)

    井贵龙; 袁峰; 郭开今; 孙玛骥

    2014-01-01

    Objective To compare the clinical effect of minimally invasive versus open transforaminal lumbar interbody fusion with unilateral pedicle screw fixation for lumbar disc herniation.Methods The data of 54 patients with lumbar disc herniation who were a-dopted from October 2009 to October 2012 were retrospectively analyzed.There were 32 males and 22 females, and the mean age was 42. 7 years (rang, 32-60 years).The level of surgery was L4/L5 in 34 patients,L5/S1 in 20 patients.All patients were divided into 2 groups according to the surgical methods, including 30 patients undergoing open transforaminal lumbar interbody fusion (OTLIF) and 24 patients undergoing minimally invasive transforaminal lumbar interbody fusion(MiTLIF).The operation time, intraoperative and postoperative blood loss, length of hospital-stay, intraoperative and postoperative complications were recorded .Intervertebral fusion rates 1 year after the operation were observed by radiographic data.Japanese Orthopaedic Association (JOA) scores were used for assessment.Results All patients were followed up for a mean period of 21.4 months (range, 12-36 months).In the MiTLIF group, the intraoperative andpostoperative blood loss was (40.2±15.6) mL, the length of hospital-stay was (6.2 ±2.4) d.Two weeks after the operation, the JOAscore was 18.7±1.9.In the OTLIF group, the intraoperative and postoperative blood loss was (203.6 ±52.8) mL, the length of hospital-stay was (10.8±4.2) d.Two weeks after the operation, the JOA score was 15.1 ±1.4.The difference between the 2 groups werestatistically significant (P 0.05). Conclusion The MiTLIF has the advantages of less blood loss, shorter hospitalization time and rapid postoperative recovery in thetreatment of lumbar disc herniation with unilateral pedicle screw fixation.%目的:比较微创经椎间孔融合内固定与传统开放经椎间孔融合内固定术治疗腰椎椎间盘突出症的临床疗效。方法2009年10月~2012年10月,对54例腰

  11. SURVEY SUBAXIAL CERVICAL VERTEBRAE FOR TRANSPEDICULAR SCREW FIXATION

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Therearemanycausesofsubaxialcervicalinstabilitysuch astrauma,degenerativedisease,neoplasm,andinfection.Therearenumerousinternalfixationproceduresthathavebeen usedforone stageposteriordecompressionandstabilizationof thecervicalspine.Recentlydevelopedposteriorplatescrew fixationprocedureshavebeenperformedinthecervicalspine byusingalateralmassscreworapediclescrewformal stage posteriordecompressionandstabilizationofthecervical spine[1].Theseveralpotentialrisksofneurovascularcomplica tions,whicharecausedbyinadeq...

  12. Bilateral pedicle screw and echelon tight closure spinal cord technique combined with implant fixations for correcting stiff spinal angular kyphosis%双侧钉棒梯次紧凑闭合脊髓短缩联合植入物内固定矫正僵硬性脊柱角状后凸

    Institute of Scientific and Technical Information of China (English)

    马华松; 李龙; 伍佳剑; 张敬; 郑蕊; 辛莘; 王晓平; 谭荣; 陈志明; 陆明; 袁伟; 徐启明; 任冬云; 麻巍

    2014-01-01

    BACKGROUND:The treatment difficulties of thoracolumbar angular kyphosis surgery are:low correction rate, hard to rebuild sagittal plane, easily induce neurological complications, postoperative loss of balance, high incidence of pseudarthrosis and postoperative loss of correction degree. OBJECTIVE:To explore the safety and efficacy of modified posterior vertebral column resection osteotomy and bilateral pedicle screw combined with echelon tight closure spinal cord technique and implant fixation for severe spinal angular kyphosis. METHODS:A total of 87 severe spinal angular kyphosis patients, 36 males and 51 females, who were treated in the Department of Orthopedics, the 306 Hospital of Chinese PLA from January 2006 to December 2013, were enrol ed in this study. They underwent posterior vertebral column resection, bilateral pedicle screw combined with echelon tight closure spinal cord, and implant fixation. Kyphosis, spinal sagittal imbalance, offset rate towards trunk side, operation time and intraoperative blood loss were observed before and after treatment. RESULTS AND CONCLUSION:The preoperative average kyphosis was 90.1° (31°-138°). The postoperative average kyphosis was 27.9° (15°-57°). The improvement rate was 76%. The improvement rate of trunk sagittal offset was 76%. Intraoperative blood loss was 800-3 000 mL, and average blood loss was 2 300 mL. The operation time was 5-7 hours, averagely 5.9 hours. Before treatment, two patients affected neurologic symptoms in double lower extremity, and their Frankel classification was grade C and became grade E after treatment. Al patients were fol owed up for 9-57 months. Bony fusion was achieved in al patients. No complications of spinal cord injury appeared, and no orthopedic angle missing occurred. These results indicate that during posterior vertebral column resection for treating severe angular stiffness of the thoracic kyphosis, blood vessels could be maintained greatly. Blood vessel injury-induced ischemic

  13. Effect of immersion in simulated body environment on mechanical properties of twist-oriented poly(lactic acid) screws

    Science.gov (United States)

    Sakaguchi, Masato; Kobayashi, Satoshi; composite engineering lab Collaboration

    Poly(lactic acid) (PLA) has been applied to bone fixation devices, since it has high biocompatibility. In order to apply PLA device to a higher loaded part, mechanical properties of PLA have been improved by uniaxial drawing. However, mechanical properties along the other loading direction than the drawing direction such as torsion were not improved. Therefore, surgeon should be carefully conducted not to brake the reinforced PLA screw when tightening. In this study, screw is focused on as a bone fixation device. In order to improve torsional strength of a PLA screw, twist-orientation method was developed. PLA screw is prepared through a series of routes including casting, extrusion drawing, twist-orientation and forging. This screw was immersed in the phosphate buffered solution for 0, 8, 16 and 24 weeks, then shear strength, orientation function, crystallinity and molecular weight were measured. As a result, twist-orientation improves the initial torsional strength of PLA screw without the decrease in initial shear strength. In addition, the shear strength on twist-oriented screw is equivalent that of non-twist oriented screw during immersion until 24 weeks. This result shown that the twist-orientation does not decrease shear strength after immersion.

  14. A screwing device for handling and assembly of micro screws

    OpenAIRE

    Gegeckaite, Asta; Hansen, Hans Nørgaard; Eriksson, Torbjörn Gerhard

    2007-01-01

    Nowadays, the application of specially designed handling devices in micro technology is an important topic and a necessity for the industry. Conventional methods for screwing can not be applied directly to micro screws. This is caused by the 3D micro object geometry and dimensions which inducing specific requirements for the torque and displacement regarding precision and repeatability. Micro screws are used as critical mechanical components in micro assemblies such as watches, dials, compute...

  15. NUT SCREW MECHANISMS

    Science.gov (United States)

    Glass, J.A.F.

    1958-07-01

    A reactor control mechanism is described wherein the control is achieved by the partial or total withdrawal of the fissile material which is in the form of a fuel rod. The fuel rod is designed to be raised and lowered from the reactor core area by means of two concentric ball nut and screw assemblies that may telescope one within the other. These screw mechanisms are connected through a magnetic clutch to a speed reduction gear and an accurately controllable prime motive source. With the clutch energized, the fuel rod may be moved into the reactor core area, and fine adjustments may be made through the reduction gearing. However, in the event of a power failure or an emergency signal, the magnetic clutch will become deenergized, and the fuel rod will drop out of the core area by the force of gravity, thus shutting down the operation of the reactor.

  16. Spontaneous urinary voiding of metallic screws in a patient with symphyseal plating for type II pelvic ring disruption

    Directory of Open Access Journals (Sweden)

    Yadav Sanjay

    2013-08-01

    Full Text Available 【Abstract】With rapid advancement in surgical techniques and improvement in implant materials, rate of internal fixation for pubic symphyseal disruption in rotationally and vertically unstable pelvic ring injuries has increased. Among various modes of implant failure, screw/ plate breakage and loosening are common complications following unstable fixation. Migration of loose screws into the urinary bladder has been reported as an extremely un-common complication of pubic symphyseal plating. Here we present a case report of a 52-year-old female who pre-sented with asymptomatic passage of screws in her urine following migration into the bladder, 2 years after symphy-seal plating for pubic diastasis in an anteroposterior com-pression pelvic ring injury. Key words: Pubic symphysis diastasis; Bone plates; Bone screws

  17. ROTARY SCREW SYSTEMS IN CEMENT

    OpenAIRE

    Taratuta V. D.; Belokur K. A.; Serga G. V.

    2016-01-01

    The article presents results of research of rotary-screw systems in relation to the creation of rotary kilns for the annealing of-cuttings in the preparation of cement clinker. Using the proposed design, in comparison with known designs of similar purpose, it significantly improves performance, reduces size and power consumption through the use of rotary screw systems in the form of screw rotors and drums made hollow with sidewalls assembled from separate strips or plates of different geometr...

  18. A Technique of Superficial Medial Collateral Ligament Reconstruction Using an Adjustable-Loop Suspensory Fixation Device.

    Science.gov (United States)

    Deo, Shaneel; Getgood, Alan

    2015-06-01

    This report describes superficial medial collateral ligament reconstruction of the knee using a novel method of graft fixation with the ACL Tightrope RT (Arthrex, Naples, FL). After tibial fixation with either a standard interference screw or staple, femoral fixation of the semitendinosus tendon is performed with the adjustable-loop suspensory fixation device, which allows for both initial graft tensioning and re-tensioning after cyclical knee range of motion. This provides the ability for the graft to accommodate for resultant soft-tissue creep and stress relaxation, thereby allowing for optimal soft-tissue tension and reduction in laxity at the end of the procedure. PMID:26258041

  19. Biomechanical optimization of different fixation modes for a proximal femoral L-osteotomy

    Directory of Open Access Journals (Sweden)

    Chen Hsih-Hao

    2009-09-01

    Full Text Available Abstract Background Numerous proposed surgical techniques have had minimal success in managing greater trochanter overgrowth secondary to retarded growth of the femoral capital epiphysis. For reconstruction of residual hip deformities, a novel type of proximal femur L-osteotomy was performed with satisfactory results. Although the clinical outcome was good, the biomechanical characteristics of the femur after such an osteotomy have not been clearly elucidated. Therefore, this study presents a three dimensional finite element analysis designed to understand the mechanical characteristics of the femur after the L-osteotomy. Methods A patient with left hip dysplasia was recruited as the study model for L-osteotomy. The normal right hip was used as a reference for performing the corrective surgery. Four FEA models were constructed using different numbers of fixation screws but the same osteotomy lengths together with four FEA models with the same number of fixation screws but different osteotomy lengths. The von Mises stress distributions and femoral head displacements were analyzed and compared. Results The results revealed the following: 1. The fixation devices (plate and screws sustained most of the external loading, and the peak value of von Mises stress on the fixation screws decreased with an increasing number of screws. 2. Additional screws are more beneficial on the proximal segment than on the distal segment for improving the stability of the postoperative femur. 3. The extent of osteotomy should be limited because local stress might be concentrated in the femoral neck region with increasing length of the L-osteotomy. Conclusion Additional screw placement on the proximal segment improves stability in the postoperative femur. The cobra-type plate with additional screw holes in the proximal area might improve the effectiveness of L-osteotomies.

  20. Open Reduction and Internal Fixation of a Fracture-dislocation of the Ankle

    Directory of Open Access Journals (Sweden)

    Yaniel Truffin Rodriguez

    2015-12-01

    Full Text Available Open reduction and internal fixation of the fracture-dislocation of the ankle with plates, screws and Kirschner wires is a well-defined treatment method. This paper presents the management of a fracture-dislocation of the right ankle in a 33-year-old female patient stabilized by using a one-third tubular plate, screws, Kirschner wires with tension-band wires. Results were satisfactory.

  1. A screwing device for handling and assembly of micro screws

    DEFF Research Database (Denmark)

    Gegeckaite, Asta; Hansen, Hans Nørgaard; Eriksson, Torbjörn Gerhard

    2007-01-01

    Nowadays, the application of specially designed handling devices in micro technology is an important topic and a necessity for the industry. Conventional methods for screwing can not be applied directly to micro screws. This is caused by the 3D micro object geometry and dimensions which inducing ...

  2. Study of second phase in bioabsorbable magnesium alloys: Phase stability evaluation via Dmol3 calculation

    Directory of Open Access Journals (Sweden)

    Huazhe Yang

    2013-11-01

    Full Text Available Thermodynamical stabilities of four conventional second phases as well as magnesium matrix in bioabsorbable magnesium alloys were investigated theoretically via computer calculation method. Model of individual phase and systems including phase and four water molecular (phase-4H2O were established to simulate the in vitro and in vivo environment. Local orbital density functional theory approach was applied to calculate the total energy for the individual phase and phase-4H2O system. The results demonstrated that all the second phases possessed higher phase stability compared with magnesium matrix, but the phase stability was quite different for different types of second phases or second phase-4H2O systems. Furthermore, a schematic process of inflammation reaction caused by magnesium alloy implants was proposed for the further evaluation on biocompatibility of different second phases.

  3. In vitro release of doxycycline from bioabsorbable materials and acrylic strips

    DEFF Research Database (Denmark)

    Larsen, T

    1990-01-01

    Treatment of marginal periodontitis may include use of local antibiotics. In the present in vitro study the bioabsorbable materials Surgicel, Tissell, and CollaCote and acrylic strips were examined for release of doxycycline into liquids and residual antibacterial activity of the materials. Pieces...... of material were incubated in 1 ml of water or human serum which was exchanged every day for 9 days. The concentration of doxycycline in the liquids was measured spectrophotometrically while the residual antibacterial activity of the materials was determined microbiologically. Surgicel constantly showed very....... In serum the acrylic strip was partly dissolved and Surgicel was totally dissolved after 2 days. Left undisturbed in serum Surgicel was not dissolved for 2 weeks. These results indicate that Surgicel and Tissel may be capable of prolonged release of doxycycline in vivo....

  4. The flying buttress construct for posterior spinopelvic fixation: a technical note

    Directory of Open Access Journals (Sweden)

    van Ooij Bas

    2011-04-01

    Full Text Available Abstract Background Posterior fusion of the spine to the pelvis in paediatric and adult spinal deformity is still challenging. Especially assembling of the posterior rod construct to the iliac screw is considered technically difficult. A variety of spinopelvic fixation techniques have been developed. However, extreme bending of the longitudinal rods or the use of 90-degree lateral offset connectors proved to be difficult, because the angle between the rod and the iliac screw varies from patient to patient. Methods We adopted a new spinopelvic fixation system, in which iliac screws are side-to-side connected to the posterior thoracolumbar rod construct, independent of the angle between the rod and the iliac screw. Open angled parallel connectors are used to connect short iliac rods from the posterior rod construct to the iliac screws at both sides. The construct resembles in form and function an architectural Flying Buttress, or lateral support arches, used in Gothic cathedrals. Results and discussion Three different cases that illustrate the Flying Buttress construct for spinopelvic fixation are reported here with the clinical details, radiographic findings and surgical technique used. Conclusion The Flying Buttress construct may offer an alternative surgical option for spinopelvic fixation in circumstances wherein coronal or sagittal balance cannot be achieved, for example in cases with significant residual pelvic obliquity, or in revision spinal surgery for failed lumbosacral fusion.

  5. Novel free-hand T1 pedicle screw method: Review of 44 consecutive cases

    Directory of Open Access Journals (Sweden)

    Mark A Rivkin

    2014-01-01

    Full Text Available Summary of Background Data: Multilevel posterior cervical instrumented fusions are becoming more prevalent in current practice. Biomechanical characteristics of the cervicothoracic junction may necessitate extending the construct to upper thoracic segments. However, fixation in upper thoracic spine can be technically demanding owing to transitional anatomy while suboptimal placement facilitates vascular and neurologic complications. Thoracic instrumentation methods include free-hand, fluoroscopic guidance, and CT-based image guidance. However, fluoroscopy of upper thoracic spine is challenging secondary to vertebral geometry and patient positioning, while image-guided systems present substantial financial commitment and are not readily available at most centers. Additionally, imaging modalities increase radiation exposure to the patient and surgeon while potentially lengthening surgical time. Materials and Methods: Retrospective review of 44 consecutive patients undergoing a cervicothoracic fusion by a single surgeon using the novel free-hand T1 pedicle screw technique between June 2009 and November 2012. A starting point medial and cephalad to classic entry as well as new trajectory were utilized. No imaging modalities were employed during screw insertion. Postoperative CT scans were obtained on day 1. Screw accuracy was independently evaluated according to the Heary classification. Results: In total, 87 pedicle screws placed were at T1. Grade 1 placement occurred in 72 (82.8% screws, Grade 2 in 4 (4.6% screws and Grade 3 in 9 (10.3% screws. All Grade 2 and 3 breaches were <2 mm except one Grade 3 screw breaching 2-4 mm laterally. Only two screws (2.3% were noted to be Grade 4, both breaching medially by less than 2 mm. No new neurological deficits or returns to operating room took place postoperatively. Conclusions: This modification of the traditional starting point and trajectory at T1 is safe and effective. It attenuates additional bone

  6. Biomechanical properties of a novel biodegradable magnesium-based interference screw

    Directory of Open Access Journals (Sweden)

    Marco Ezechieli

    2016-06-01

    Full Text Available Magnesium-based interference screws may be an alternative in anterior/posterior cruciate ligament reconstruction. The well-known osteoconductive effects of biodegradable magnesium alloys may be useful. It was the purpose of this study to evaluate the biomechanical properties of a magnesium based interference screw and compare it to a standard implant. A MgYREZr-alloy interference screw and a standard implant (Milagro®; De Puy Mitek, Raynham, MA, USA were used for graft fixation. Specimens were placed into a tensile loading fixation of a servohydraulic testing machine. Biomechanical analysis included pretensioning of the constructs at 20 N for 1 min following cyclic pretensioning of 20 cycles between 20 and 60 N. Biomechanical elongation was evaluated with cyclic loading of 1000 cycles between 50 and 200 N at 0.5 Hz. Maximum load to failure was 511.3±66.5 N for the Milagro® screw and 529.0±63.3 N for magnesium-based screw (ns, P=0.57. Elongations after preload, during cyclical loading and during failure load were not different between the groups (ns, P>0.05. Stiffness was 121.1±13.8 N/mm for the magnesiumbased screw and 144.1±18.4 for the Milagro® screw (ns, P=0.32. MgYREZr alloy interference screws show comparable results in biomechanical testing to standard implants and may be an alternative for anterior cruciate reconstruction in the future.

  7. Frictional performance of ball screw

    International Nuclear Information System (INIS)

    As feed screws, ball screws have become to be adopted in place of trapezoidal threads. The structure of ball screws is complex, but those are the indispensable component of NC machine tools and machining centers, and are frequently used for industrial robots. As the problems in the operation of ball screws, there are damage, life and the performance related to friction. As to the damage and life, though there is the problem of the load distribution on balls, the results of the research on rolling bearings are applied. The friction of ball screws consists of the friction of balls and a spiral groove, the friction of a ball and a ball, the friction in a ball-circulating mechanism and the viscous friction of lubricating oil. It was decided to synthetically examine the frictional performance of ball screws, such as driving torque, the variation of driving torque, efficiency, the formation of oil film and so on, under the working condition of wide range, using the screws with different accuracy and the nuts of various circuit number. The experimental setup and the processing of the experimental data, the driving performance of ball screws and so on are reported. (Kako, I.)

  8. Screw/stud removal tool

    Science.gov (United States)

    Daniels, K.; Herrick, D. E.; Rothermel, L.

    1980-01-01

    Tool removes stubborn panheaded screws or studs where conventional tools would be either too weak or inconvenient to use. Screws with damaged heads or slots can also be removed this way. Tool can be worked with one hand and easily fits limited-access and blind areas. It can be made in various sizes to fit different screwheads.

  9. Factors influencing success of cement versus screw-retained implant restorations: a clinical review

    Directory of Open Access Journals (Sweden)

    Ahmad Manawar

    2012-10-01

    Full Text Available Aim: As more and more dental practitioners are focusing on implant-supported fixed restorations, some clinicians favor the use of cement retained restorations while others consider screw retained prosthesis to be the best choice. Discussion: In screw-retained restorations, the fastening screw provides a solid joint between the restoration and the implant abutment, while in cement-retained prostheses the restorative screw is eliminated to enhance esthetics, occlusal stability, and passive fit of the restorations. The factors that influence the type of fixation of the prostheses to the implants like passivity of the framework, ease of fabrication, occlusion, esthetics, accessibility, retention and retrievability are discussed in this article with scientific studies demonstrating superior outcomes of one technique over another. Screwretained implant restorations have an advantage of predictable retention, retrievability and lack of potentially retained subgingival cement. However, a few disadvantages exist such as precise placement of the implant for optimal and esthetic location of the screw access hole and obtaining passive fit. On the other hand, cement retained restorations eliminate unesthetic screw access holes, have passive fit of castings, reduced complexity of clinical and lab procedures, enhanced esthetics, reduced cost factors and non disrupted morphology of the occlusal table. Conclusion: This article compares the advantages, potential disadvantages and limitations of screw and cement retained restorations and their specific implications in the most common clinical situation.

  10. The Use of MMF Screws: Surgical Technique, Indications, Contraindications, and Common Problems in Review of the Literature.

    Science.gov (United States)

    Cornelius, Carl-Peter; Ehrenfeld, Michael

    2010-06-01

    Mandibulo-maxillary fixation (MMF) screws are inserted into the bony base of both jaws in the process of fracture realignment and immobilisation. The screw heads act as anchor points to fasten wire loops or rubber bands connecting the mandible to the maxilla. Traditional interdental chain-linked wiring or arch bar techniques provide the anchorage by attached cleats, hooks, or eyelets. In comparison to these tooth-borne appliances MMF screws facilitate and shorten the way to achieve intermaxillary fixation considerably. In addition, MMF screws help to reduce the hazards of glove perforation and wire stick injuries. On the downside, MMF screws are attributed with the risk of tooth root damage and a lack of versatility beyond the pure maintenance of occlusion such as stabilizing loose teeth or splinting fragments of the alveolar process. The surgical technique of MMF screws as well as the pros and cons of the clinical application are reviewed. The adequate screw placement to prevent serious tooth root injuries is still an issue to rethink and modify conceptual guidelines. PMID:22110819

  11. A STUDY OF INTERNAL FIXATION OF INTRACAPSULAR FRACTURE NECK OF FEMUR IN ADULTS BY MULTIPLE CANNULATED CANCELLOUS LAG SCREEWS

    Directory of Open Access Journals (Sweden)

    Sanjeevaiah

    2015-07-01

    Full Text Available INTRODUCTION: Fractures of neck of femur have always presented great challenges to the Orthopaedic surgeons. In many ways today the unsolved fracture as per as treatment and results are concerned. Fractures of neck of femur are usually entirely intracapsular results depend upon extent of injury and adequacy of reduction and fixation. Fixation with cannulated cancellous lagscrews is usually adequate for femoral neck fractures. Lateral cortex place a very important role in screw fixation. AIMS & OBJECTIVES : To evaluate the cannulated cancellous lagscrew fixation in case of intra capsular neck of femur. MATERIAL AND METHODS : The patients with intra capsular fracture neck of femur are evaluated with pre - operative X - Rays of the concerned hip joints both in anterio posterior and lateral views and their outcome post operatively after fixation with cancellous screws. The outcome was evaluated in terms of pain relief and ambulation after surgery. The patients followed upto one year to assess the outcome. RESULTS: The excellent results was obtained in 22.63% good result in 59.09% fair in 9.09% poor in 9.09%. Nonunion and loosening of screws in one case. Nonunion and extrusion of screws in one case. Cut through o f the screws in to the articular surface leading to painful joint in one case. Most of the cases are fracture neck of femur were in the age group of 20 to 40 with male preponderance. CONCLUSION: By the usage of cannulated cancellous lag screws compression of the fracture site is achieved, with also avoids rotations. Multiple cannulated cancellous lagscrews in intra capsular neck of femur is an easy procedure with encouraging results. AIM : An attempt has been made to evaluate the role of multiple cannulated cancellous lag Screws in internal fixation of intracapsular fracture neck of femur. Patients selected for this operation were between the age group of 15 to 55 years with intracapsular fracture neck of femur during the years 2011 to 2014.

  12. MANAGEMENT OF UNSTABLE THORACOLUMBAR FRACTURES BY POSTERIOR INSTRUMENTATION WITH TRANSPEDICULAR PEDICLE SCREWS AND CONNECTING RODS

    Directory of Open Access Journals (Sweden)

    Jayaram

    2015-09-01

    Full Text Available OBJECTIVE: To evaluate the use of pedicle screw and rod fixation in post - traumatic unstable thoracolumbar Spine fractures. METHODS: Thirty six patients with posttraumatic instability of thoracolumbar were included in the study. Thoracolumbar injury severity scoring was used to assess spinal instability. All patients underwent open reduction and internal fixation by posterior approach. Pedicles were localized using detailed anatomical landmarks and intraoperative imaging. The neurological status of the patients was assessed using ASIA grading and any other complications were noted up to 6 months. RESULTS: There were 36 patients with unstable thoracolumbar junction injuries who were managed with pedicle screws and rods. M ales were more affected (M: F ratio was 8: 1. AO type A was the commonest. The most common level was L1. None of the patients deteriorated after surgery. 27 patients with incomplete cord injury showed at least one frankel grade improvement. 8 patients with complete cord injury showed no improvement. The mean kyphotic angle by Cobb’s method was 20.8° on admission, 4.6° post operatively and 6.1° at latest follow - up . Average anterior vertebral body height at the time of admission was 52%, post op was 85% and at final follow up was 80%. T here was 1 case of malpositiong of screw and 5 patients developed bed sores. CONCLUSION: Pedicle screw fixation is a useful choice for thoracolumbar junction injuries for achieving reduction and stability, without affecting extra motion segments.

  13. Simple coating with fibronectin fragment enhances stainless steel screw osseointegration in healthy and osteoporotic rats.

    Science.gov (United States)

    Agarwal, Rachit; González-García, Cristina; Torstrick, Brennan; Guldberg, Robert E; Salmerón-Sánchez, Manuel; García, Andrés J

    2015-09-01

    Metal implants are widely used to provide structural support and stability in current surgical treatments for bone fractures, spinal fusions, and joint arthroplasties as well as craniofacial and dental applications. Early implant-bone mechanical fixation is an important requirement for the successful performance of such implants. However, adequate osseointegration has been difficult to achieve especially in challenging disease states like osteoporosis due to reduced bone mass and strength. Here, we present a simple coating strategy based on passive adsorption of FN7-10, a recombinant fragment of human fibronectin encompassing the major cell adhesive, integrin-binding site, onto 316-grade stainless steel (SS). FN7-10 coating on SS surfaces promoted α5β1 integrin-dependent adhesion and osteogenic differentiation of human mesenchymal stem cells. FN7-10-coated SS screws increased bone-implant mechanical fixation compared to uncoated screws by 30% and 45% at 1 and 3 months, respectively, in healthy rats. Importantly, FN7-10 coating significantly enhanced bone-screw fixation by 57% and 32% at 1 and 3 months, respectively, and bone-implant ingrowth by 30% at 3 months compared to uncoated screws in osteoporotic rats. These coatings are easy to apply intra-operatively, even to implants with complex geometries and structures, facilitating the potential for rapid translation to clinical settings. PMID:26100343

  14. Rotational Stability of Scaphoid Osteosyntheses: An In Vitro Comparison of Small Fragment Cannulated Screws to Novel Bone Screw Sets

    Science.gov (United States)

    Erhart, Jochen; Unger, Ewald; Schefzig, Philip; Varga, Peter; Trulson, Inga; Gormasz, Anna; Trulson, Alexander; Reschl, Martin; Hagmann, Michael; Vecsei, Vilmos; Mayr, Winfried

    2016-01-01

    Background The current standard of care for operative repair of scaphoid fractures involves reduction and internal fixation with a single headless compression screw. However, a compression screw in isolation does not necessarily control rotational stability at a fracture or nonunion site. The single screw provides rotational control through friction and bone interdigitation from compression at the fracture site. We hypothesize that osteosyntheses with novel bone screw sets (BSS) equipped with anti-rotational elements provide improved rotational stability. Methods Stability of osteosynthesis under increasing cyclic torsional loading was investigated on osteotomized cadaveric scaphoids. Two novel prototype BSS, oblique type (BSS-obl.) and longitudinal type (BSS-long.) were compared to three conventional screws: Acutrak2®mini, HCS®3.0 and Twinfix®. Biomechanical tests were performed on scaphoids from single donors in paired comparison and analyzed by balanced incomplete random block design. Loading was increased by 50 mNm increments with 1,000 cycles per torque level and repeated until a rotational clearance of 10°. Primary outcome measure was the number of cycles to 10° clearance, secondary outcome measure was the maximum rotational clearance for each torque level. Findings BSS-obl. performed significantly better than Acutrak2®mini and HCS® (p = 0.015, p<0.0001). BSS-long. performed significantly better than HCS® (p = 0.010). No significant difference in performance between BSS-obl. and BSS-long. (p = 0.361), between BSS obl. and Twinfix® (p = 0.50) and BSS long. and Twinfix® (p = 0.667) was detected. Within the torque range up to 200 mNm, four of 21 (19%) BSS-long. and four of 21 (19%) BSS-obl. preparations showed early failure. The same loading led to early failure in four (29%) Twinfix®, seven (50%) Acutrak2®mini and 10 (71%) HCS® of 14 screw samples, respectively. Conclusions For both BSS and to a lesser extent for Twinfix® (as dual-component screw

  15. ROTARY SCREW SYSTEMS IN CEMENT

    Directory of Open Access Journals (Sweden)

    Taratuta V. D.

    2016-01-01

    Full Text Available The article presents results of research of rotary-screw systems in relation to the creation of rotary kilns for the annealing of-cuttings in the preparation of cement clinker. Using the proposed design, in comparison with known designs of similar purpose, it significantly improves performance, reduces size and power consumption through the use of rotary screw systems in the form of screw rotors and drums made hollow with sidewalls assembled from separate strips or plates of different geometrical shapes with form inside the screw breaks or smooth edges, screw surfaces and screw grooves. It is shown that the housing of the rotary kiln is expedient to produce helical surfaces whose centers of curvature are located within the housing. Using the proposed constructions rotary kiln during the firing when preparing cement wedge can increase the speed of rotation of the housing, furnaces 5-10 times due to changes in the rotary-screw systems increase efficiency and reduce the size of furnaces

  16. The pullout performance of pedicle screws

    CERN Document Server

    Demir, Teyfik

    2015-01-01

    This brief book systematically discusses all subjects that affect the pullout strength of pedicle screws. These screws are used in spinal surgeries to stabilize the spine. The holding strength of the pedicle screw is vital since loosening of the pedicle screws can cause revision surgeries. Once the pedicle screw is pulled out, it is harder to obtain same stabilization for the fused vertebrae. The book reviews the effect of screw designs, application techniques, cement augmentation, coating of the screw and test conditions on the pullout strength. The studies with finite element analysis were also included.

  17. Spline screw autochanger

    Science.gov (United States)

    Vranish, John M.

    1993-06-01

    A captured nut member is located within a tool interface assembly and being actuated by a spline screw member driven by a robot end effector. The nut member lowers and rises depending upon the directional rotation of the coupling assembly. The captured nut member further includes two winged segments which project outwardly in diametrically opposite directions so as to engage and disengage a clamping surface in the form of a chamfered notch respectively provided on the upper surface of a pair of parallel forwardly extending arm members of a bifurcated tool stowage holster which is adapted to hold and store a robotic tool including its end effector interface when not in use. A forward and backward motion of the robot end effector operates to insert and remove the tool from the holster.

  18. Split spline screw

    Science.gov (United States)

    Vranish, John M. (Inventor)

    1993-01-01

    A split spline screw type payload fastener assembly, including three identical male and female type split spline sections, is discussed. The male spline sections are formed on the head of a male type spline driver. Each of the split male type spline sections has an outwardly projecting load baring segment including a convex upper surface which is adapted to engage a complementary concave surface of a female spline receptor in the form of a hollow bolt head. Additionally, the male spline section also includes a horizontal spline releasing segment and a spline tightening segment below each load bearing segment. The spline tightening segment consists of a vertical web of constant thickness. The web has at least one flat vertical wall surface which is designed to contact a generally flat vertically extending wall surface tab of the bolt head. Mutual interlocking and unlocking of the male and female splines results upon clockwise and counter clockwise turning of the driver element.

  19. Percutaneous Sacroiliac Screw Technique.

    Science.gov (United States)

    Tidwell, John; Cho, Rosa; Reid, J Spence; Boateng, Henry; Copeland, Carol; Sirlin, Edward

    2016-08-01

    Remembering that preoperative planning, surgical indications, and fracture reduction are paramount for this procedure, presented here is our technique for performing percutaneous sacroiliac screws, both transiliac-transsacral and sacral style. A combination of video, still pictures, and fluoroscopy images will guide the viewer through the process we routinely use highlighting specific details. Patient positioning and intraoperative fluoroscopy imaging are critical to a successful procedure. Although inlet and outlet films remain important, we find the procedure best started on the lateral sacral view to reduce the need for start site, trajectory, and imaging position changes during the case. A cannulated pig sticker (drill guide) used with long drill tip guide wires provide improved manual control to both finding a good start site and directing the trajectory. For patient safety, sacral anatomy and safe zones are discussed as well. Using these technical points will help make this a successful procedure. PMID:27441927

  20. Removal torque of nail interlocking screws is related to screw proximity to the fracture and screw breakage.

    Science.gov (United States)

    White, Alexander A; Kubacki, Meghan R; Samona, Jason; Telehowski, Paul; Atkinson, Patrick J

    2016-06-01

    Studies have shown that titanium implants can be challenging to explant due to the material's excellent biocompatibility and resulting osseointegration. Clinically, titanium alloy nail interlocking screws may require removal to dynamize a construct or revise the nail due to nonunion, infection, pain, or periprosthetic fracture. This study was designed to determine what variables influence the removal torque for titanium alloy interlocking screws. An intramedullary nail with four interlocking screws was used to stabilize a 1-cm segmental femoral defect in a canine model for 16 weeks. The animals were observed to be active following a several-day recovery after surgery. In six animals, the femora and implanted nail/screws were first tested to failure in torsion to simulate periprosthetic fracture of an implant after which the screws were then removed. In four additional animals, the screws were removed without mechanical testing. Both intraoperative insertional and extraction torques were recorded for all screws. Mechanical testing to failure broke 10/24 screws. On average, the intact screws required 70% of the insertional torque during removal while broken screws only required 16% of the insertional torque (p < 0.001). In addition, intact screws closer to the fracture required 2.8 times more removal torque than the outboard distal screw (p < 0.005). On average, the angle of rotation to peak torque was ∼80°. The peak axial load did not significantly correlate with the torque required to remove the screws. On average, the removal torque was lower than at the time of insertion, and less torque was required to remove broken screws and screws remote to the fracture. However, broken screws will require additional time to retrieve the remaining screw fragment. This study suggests that broken screws and screws in prematurely active patients will require less torque to remove. PMID:27129382

  1. Clinical efficacy of responsibility segment laminectomy and lateral mass screw fixation in the treatment of patients with cervical spondylotic myelopathy (CSM) combined with ossification of posterior longitudinal ligament (OPLL)%责任节段椎板全切侧块螺钉内固定术治疗伴后纵韧带骨化症的多节段颈椎病疗效分析

    Institute of Scientific and Technical Information of China (English)

    陈华星; 杨圣; 芦健民; 李树强; 邱兴; 廉皓屹; 付大鹏

    2013-01-01

    [目的]探讨责任节段椎板全切侧块螺钉内固定术治疗伴后纵韧带骨化症的多节段颈椎病的临床疗效.[方法]回顾性分析2007年5月~ 2010年10月手术治疗的多节段颈椎病伴后纵韧带骨化症表现的患者61例,所选多节段病例中(≥3),3个节段50例,4个节段11例.分别采用前后路两种术式,都在显微镜辅助下操作,其中颈后路责任节段椎板全切除侧块螺钉内固定术47例(A组),颈前路椎体次全切钛网植骨融合钛板内固定术14例(B组),分别记录两组手术前后JOA评分及轴性症状VAS评分,加以评定两组术后神经功能改善率(RIS)情况,通过对比分析责任节段椎板全切侧块螺钉内固定术的临床疗效.[结果] 61例患者均获得随访,随访时间在6~38个月,平均16个月.A组的JOA和VAS评分术前分别为(7.2±1.5)、(6.8±2.1)分;术后1周分别为(13.2±2.4)、(2.5±1.4)分;末次随访分别为(13.7±1.8)、(2.3±2.0)分;RIS为(59.92±13.46)%.B组术前JOA和VAS评分分别为(7.5±1.3)、(7.1±2.4)分;术后1周分别为(13.8±2.1)、(2.3±1.5)分;末次随访分别为(14.1±1.6)、(2.2±1.8)分;RIS为(62.28±14.16)%.A组、B组术后1周、末次随访JOA和VAS评分与术前比较均有显著性差异(P<0.05),两组间的术前JOA、VAS评分及术后RIS无统计学差异(P>0.05).[结论]颈前、后路治疗伴后纵韧带骨化症的多节段颈椎病均取得良好的手术疗效,少节段局灶性后纵韧带骨化应以前路为主,对于多节段连续性后纵韧带骨化尤其椎管明显狭窄者,后路责任节段椎板全切侧块螺钉内固定术在有效改善神经功能、轴性症状的同时兼顾了良好的脊柱稳定性,是一种相对安全灵活、使用范围较广的术式.%[ Objective] To observe the clinical outcome of responsibility segment laminectomy and lateral mass screw fixation in the treatment of cervical spondylotic myelopathy (CSM) combined with ossification of

  2. Biomechanical analysis of different types of pedicle screw augmentation: a cadaveric and synthetic bone sample study of instrumented vertebral specimens.

    Science.gov (United States)

    Chao, Kuo-Hua; Lai, Yu-Shu; Chen, Wen-Chuan; Chang, Chia-Ming; McClean, Colin J; Fan, Chang-Yuan; Chang, Chia-Hao; Lin, Leou-Chyr; Cheng, Cheng-Kung

    2013-10-01

    This study aims to determine the pull-out strength, stiffness and failure pull-out energy of cement-augmented, cannulated-fenestrated pedicle screws in an osteoporotic cadaveric thoracolumbar model, and to determine, using synthetic bone samples, the extraction torques of screws pre-filled with cement and those with cement injected through perforations. Radiographs and bone mineral density measurements from 32 fresh thoracolumbar vertebrae were used to define specimen quality. Axial pull-out strength of screws was determined through mechanical testing. Mechanical pull-out strength, stiffness and energy-to-failure ratio were recorded for cement-augmented and non-cement-augmented screws. Synthetic bone simulating a human spinal bone with severe osteoporosis was used to measure the maximum extraction torque. The pull-out strength and stiffness-to-failure ratio of cement pre-filled and cement-injected screws were significantly higher than the non-cement-augmented control group. However, the cement pre-filled and cement-injected groups did not differ significantly across these values (p=0.07). The cement pre-filled group had the highest failure pull-out energy, approximately 2.8 times greater than that of the cement-injected (pcement-injected group had a greater maximum extraction torque than the cement pre-filled group, but was statistically insignificant (p=0.17). The initial fixation strength of cannulated screws pre-filled with cement is similar to that of cannulated screws injected with cement through perforations. This comparable strength, along with the heightened pull-out energy and reduced extraction torque, indicates that pedicle screws pre-filled with cement are superior for bone fixation over pedicle screws injected with cement. PMID:23669371

  3. Combination therapy of transforaminal lumbar interbody fusion and Wiltse pedicle screw fixation approach in the treatment of the lumbar disc protrusion%经椎间孔椎间融合术联合Wiltse入路椎弓根固定治疗腰椎间盘突出症

    Institute of Scientific and Technical Information of China (English)

    隋海涛; 冯涛; 李亮; 于学忠

    2013-01-01

    [Objective] To compare the clinical effects of transforaminal lumbar interbody fusion with Wiltse pedicle screw fixation approach combined (TLIF,group A) and posterior lumbar interbody fusion (PLIF,group B).[Methods] From March 2008 to September 2012,186 patients on treatment for lumbar disc were divided into two groups:there were 104 patients in group A,48 males and 56 females,aged between 43 to 65,55 on average and 82 patients in group B,39 males and 43 females,aged between 45 to 67,57 on average.The bleeding volume,average time of operation,the rate of complications,fusion rate,the intervertebral space and the improvements in symptoms were compared and statistical analyzed.Visual analogue pain score (VAS) of low back pain and leg pain as well as the Oswestry disability index (ODI) were used in preoperative assessment and postoperative follow-up for symptoms evaluation.[Results] There were no statistical differences in the age,sex,intervertebral space,VAS score and ODI score before operation.The follow-up times without statistical difference were 26 months on average in group A and 23 months in group B.No significant differences were found between the two groups in last VAS scores of leg pain,ODI scores,fusion rate and intervertebral space (P > O.05).But group A had significant (P < 0.01) advantages of the bleeding volume,average time of operation,the rate of complications and the last VAS scores of low back pain.Significant improvements (P < 0.01) of intervertebral space,VAS scores and ODI scores after operation were ensured in both groups by the last follow-ups.[Conclusion] The efficacy of TLIF and PLIF are both satisfactory,but TLIF is better for less trauma,fewer complications and lower residual low back pain rate after operation.%[目的]比较经椎间孔腰椎椎间融合术(transforaminal lumbar interbody fusion,TLIF,A组)联合Wiltse入路椎弓根固定与传统经后路腰椎椎间融合术(posterior lumbar interbody fusion,PLIF,B组)治疗腰

  4. Computer-assisted percutaneous scaphoid fixation: concepts and evolution.

    Science.gov (United States)

    Smith, Erin J; Ellis, Randy E; Pichora, David R

    2013-11-01

    Background The treatment for undisplaced scaphoid waist fractures has evolved from conventional cast immobilization to percutaneous screw insertion. Percutaneous fixation reduces some of the risks of open surgery, but can be technically demanding and carries the risk of radiation exposure. Recently, computer-assisted percutaneous scaphoid fixation (CAPSF) has been gaining interest. Materials and Methods Conventional percutaneous scaphoid fixation is performed under fluoroscopic guidance and involves insertion of a guide wire along the length of the scaphoid to facilitate placement of a cannulated screw. Adapting computer-assisted techniques for scaphoid fixation poses several unique challenges including patient tracking and registration. Results To date, five groups have successfully implemented systems for CAPSF. These systems have implemented wrist immobilization strategies to resolve the issue of patient tracking and have developed unique guidance techniques incorporating 2D fluoroscope, cone-beam CT, and ultrasound, to circumvent patient-based registration. Conclusions Computer-aided percutaneous pinning of scaphoid waist fractures can significantly reduce radiation exposure and has the potential to improve the accuracy of this procedure. This article reviews the rationale for, and the evolution of, CAPSF and describes the key principles of computer-assisted technology. PMID:24436833

  5. Influences of implant condyle geometry on bone and screw strains in a temporomandibular implant.

    Science.gov (United States)

    Mesnard, M; Ramos, A; Simões, J A

    2014-04-01

    A 3D finite element model of an in vitro implanted mandible was analysed. The load point was placed on the condyle in three positions (inside the mouth, centred and outside) to simulate different contact points between the mandible condyle and the temporal bone. The strain fields in the condyle were assessed and detailed around the surgical screws. The temporomandibular implant studied here was modelled on a commercial device that uses four screws to fix it in vivo in a very similar position. The boundary conditions of the numerical model simulated a load on the incisors with a 15 mm mouth aperture. The same contact loads were applied to the two condyles. Numerical results were successfully obtained for the three different contact points: the inside contact produced lower strains on the condyle. The first screw created a critical strain distribution in the bone, just under the screw. The study shows that centred and inside contact induces lower strain distributions. This suggests that spherical condyle geometry should be applied in order to reduce the strains in fixation. As the top screw was observed to play the most critical role, the third screw is in fact unnecessary, since the lower strain distribution suggests that it will be loosened. PMID:23726645

  6. 椎弓根螺钉内固定材料置入并植骨融合后路矫正治疗重度僵硬性青少年特发性脊柱侧凸20例%Posterior correction using pedicle screw fixation combined with bone grafting and fusion for treatment of severe and rigid adolescent idiopathic scoliosis in 20 cases

    Institute of Scientific and Technical Information of China (English)

    臧危平; 刘祖德; 李展春; 冯宇; 张磊

    2008-01-01

    主弯平均Cobb角从术前的82°(75o~ 92o)矫正到31°(22°~37°),平均矫正率为62%.③双肩高度差及住院时间:术后脊柱侧位片均显示患者胸腰椎基本恢复正常后凸及前凸,平均双肩高度差为7.5 mm(0~11 mm),患者住院日为8~11 d, 平均9 d.④随访结果:所有患者均获术后4年随访,所有侧凸主弯矫正角度未发生丢失,固定节段全部融合,无断钉、断棒发生.结论:单纯后路椎弓根螺钉内固定材料置入并植骨融合术能有效治疗主弯在75o~92o,柔韧性≥ 20%的重度僵硬性青少年特发性脊柱侧凸.%BACKGROUND: Traditional anterior release followed by posterior correction and fusion is frequently used to treat severe and rigid adolescent idiopathic scoliosis, which is considered as Cobb angle of the major curve > 65° and flexibility < 34.5%; however, there are a great majority of complications. Whether isolated posterior correction using pedicle screw fixation combining with bone grafting and fusion may provide better effects on severe and rigid adolescent idiopathic scoliosis needs to be further studied.OBJECTIVE: To evaluate isolated posterior correction using pedicle screw fixation combining with bone grafting and fusion for the treatment of severe and rigid adolescent idiopathic scoliosis. DESIGN: Case analysis.SETTING: Department of Orthopaedics, Renji Hospital, Medical College of Shanghai Jiao Tong University.PARTICIPANTS: Twenty patients with severe and rigid adolescent idiopathic scoliosis, including 8 males and 12 females, were selected from Department of Orthopaedics, Renji Hospital, Medical College of Shanghai Jiaotong University from June 1999 to August 2005. They were 12-18 years old, and the mean age was 14.6 years. All patients were finally diagnosed as X-ray of whole spine. According to King-Moe criteria, patients were classified into type Ⅰ(n =4), type Ⅱ(n =6), type Ⅲ (n =5), type Ⅳ(n =3) and type Ⅴ(n =2). Before surgery, mean Cobb angle of the major curve was 82

  7. Technique tip: percutaneous fixation of partial incongruous Lisfranc injuries in athletes.

    Science.gov (United States)

    Bleazey, Scott T; Brigido, Stephen A; Protzman, Nicole M

    2013-06-01

    Open reduction with screw fixation is considered the standard surgical approach for injuries of the Lisfranc complex in athletes. However, multiple incisions are required, which increase the risk for postoperative complications. We present a novel percutaneous reduction and solid screw fixation technique that may be a viable option to address partial incongruous injuries of the Lisfranc complex in athletes. At our institution, no intraoperative or postoperative complications have been encountered. Screw breakage did not occur. Reduction of the second metatarsal was considered anatomic across all patients. All patients have returned to their respective sport without limitation. The percutaneous approach appears to decrease complications while the targeting-reduction guide appears to precisely reduce the injury. Consequently, outcomes have been more consistent and predictable. The authors note that this percutaneous approach is specific to partial incongruous injuries of the Lisfranc complex. When presented with more extensive injuries, the authors advocate an open approach. PMID:23631892

  8. Pull-out strength comparison of a novel expanding fastener against an orthopaedic screw in an ovine vertebral body: an ex-vivo study.

    Science.gov (United States)

    Oldakowski, Matthew; Oldakowska, Intan; Kirk, Thomas B; Ford, Chris T; Sercombe, Tim B; Hardcastle, Philip; Day, Robert E

    2016-01-01

    The purpose of this study was to mechanically test a novel Unthreaded Expandable Fastener (UEF), manufactured using Selective Laser Melting, which was designed for fixation in the cervical lateral mass. The pull-out strength and stiffness of the prototype UEFs was evaluated in a non-osteoporotic ovine bone model against equivalent screws. The prototype UEF demonstrated a 41% increase in failure force and a 60% reduction in failure force standard deviation compared to the screws. All bone samples were micro CT-scanned and no significant differences in bone microstructural properties was found between the screw and UEF sample sets, indicating that the UEFs may be less sensitive to bone quality variation. This increased performance can potentially translate into improved surgical outcome and reduced surgical risk for lateral mass fixation. With further design optimisation, additional improvement in performance over screws may be possible in future studies. PMID:26758778

  9. Neuron attachment properties of carbon negative-ion implanted bioabsorbable polymer of poly-lactic acid

    International Nuclear Information System (INIS)

    Modification of a bioabsorbable polymer of poly-lactic acid (PLA) by negative carbon ion implantation was investigated with resect to radiation effects on surface physical properties and nerve-cell attachment properties. Carbon negative ions were implanted to PLA at energy of 5-30 keV with a dose of 1014-1016 ions/cm2. Most C-implanted PLA samples showed contact angles near 80 deg. and almost same as that of unimplanted PLA, although a few samples at 5 keV and less 3x1014 ions/cm2 had contact angles larger than 90 deg. The attachment properties of nerve cells of PC-12h (rat adrenal phechromocytoma) in vitro were studied. PC-12h cells attached on the unimplanted region in C-implanted PLA samples at 5 and 10 keV. On the contrary, the nerve cells attached on only implanted region for the C-implanted PLA sample at 30 keV and 1x1015 ions/cm2

  10. Lagged Syndesmotic Fixation: Our Clinical Experience.

    Science.gov (United States)

    Kwaadu, Kwasi Yiadom; Fleming, Justin James; Salmon, Trudy

    2015-01-01

    Ankle fractures are very common, and although algorithms are in place for osseous management, consensus has not been reached regarding treatment of associated ligamentous injuries. Although tibiofibular syndesmotic stabilization can be done using different forms of fixation, the biomedical literature has long emphasized the risk of long-term restriction of ankle mobility with the use of lagged transfixation. However, when reduction cannot be maintained with positional fixation, we found that lagging the syndesmotic screw helped to maintain the reduction without causing functional restriction. In this report, we describe our experience with patients who had undergone lagged tibiofibular transfixation and were available for short- to intermediate-term follow-up to assess ankle function. A total of 31 patients (32.63% of 95 consecutive patients) were available at a mean of 34.87 (range 18 to 52) months to complete the American Orthopedic Foot and Ankle Society ankle-hindfoot questionnaire. The mean score was 88.38 (range 42 to 100) points at a mean follow-up interval of 34.87 (range 18 to 52) months. Of 31 patients, 19 had an AOFAS score of 90 points, 9 an AOFAS score of 80 to 89 points, 2 an AOFAS score of 60 to 69 points, and 1 an AOFAS score of ankle kinematics than positional syndesmotic fixation. PMID:25736445

  11. Primary stability of inferior tilt fixation of the glenoid component in reverse total shoulder arthroplasty: A finite element study.

    Science.gov (United States)

    Chae, Soo-Won; Lee, Haea; Kim, Soo Min; Lee, Juneyoung; Han, Seung-Ho; Kim, Soung-Yon

    2016-06-01

    Glenoid component fixation with inferior tilt has been suggested as one of the surgical methods to decrease scapular notching and improve stability, but its clinically beneficial effect remains a concern. We evaluated the influence of inferior tilt fixation of the glenoid component on primary stability in reverse total shoulder arthroplasty by finite element analysis. Finite element models were constructed from cadaveric scapulae of females over the age of 60 years and glenoid components from reverse total shoulder arthroplasty. The relative micromotion at the bone-glenoid component interface, distribution of bone stress under the glenoid component and around the screws, contact area between the bone and screws, and cut surface area of the cancellous bone exposed after glenoid reaming were analyzed and compared between a neutral and 10° inferior tilt fixation of the glenoid component. The 10° inferior tilt fixation demonstrated greater relative micromotion and higher bone stress than the neutral tilt fixation. Eccentric reaming, which is done to produce the inferior tilt fixation of the glenoid component, increased glenoid cancellous bone exposure and decreased bone-screws contact area. Inferior tilt fixation of the glenoid component may adversely affect primary stability and longevity after reverse total shoulder arthroplasty. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1061-1068, 2016. PMID:26621211

  12. Comparison of the clinical accuracy of cervical (C2-C7) pedicle screw insertion assisted by fluoroscopy, computed tomography-based navigation, and intraoperative three-dimensional C-arm navigation

    Institute of Scientific and Technical Information of China (English)

    LIU Ya-jun; TIAN Wei; LIU Bo; LI Qin; HU Lin; LI Zhi-yu; YUAN Qiang; L(U) Yan-wei; SUN Yu-zhen

    2010-01-01

    Background The complicated anatomy of the cervical spine and the variation among pedicles reduces the accuracy and increases the risk of neurovascular complications associated with screw implantation in this region. In this study, we compared the accuracy of cervical (C2-C7) pedicle screw fixation assisted by X-ray fluoroscopy, computed tomography (CT)-based navigation, or intraoperative three-dimensional (3D) C-arm navigation.Methods This prospective cohort study was performed in 82 consecutive patients who underwent cervical pedicle screw fixation. The accuracy of screw insertion was assessed by postoperative CT scan with 3D reconstruction. The accuracy of screw insertion was assessed as: excellent (screw completely within pedicle); acceptable (≤ 1 mm screw outside pedicle cortex); poor (>1 mm screw outside pedicle cortex).Results A total of 145 screws were inserted in 24 patients who underwent C-arm fluoroscopy. Of these, 96 screws (66.2%) were excellent, 37 (25.5%) were acceptable, and 12 (8.3%) were poor. One hundred and fifty-nine screws were inserted in 29 patients in the CT-based navigation group. Among these, 141 (88.7%) were excellent, 14 (8.8%) were acceptable, and 4 (2.5%) were poor. A total of 140 screws were inserted in 29 patients in the intraoperative 3D C-arm navigation group, of which 127 (90.7%) were excellent, and 13 (9.3%) were acceptable. No severe or permanent neurovascular complications associated with screw insertion were observed in any patient.Conclusione CT-based and intraoperative 3D C-arm navigation were similarly accurate, and were both significantly more accurate than C-arm fluoroscopy for guiding cervical pedicle screw fixation. They were able to accurately guide the angle and depth of screw placement using visual 3D images. These two techniques are therefore preferable for high-risk cervical pedicle screw fixation. The ease and convenience of intraoperative 3D C-arm navigation suggests that it may replace virtual

  13. Degradation behaviour of LAE442-based plate–screw-systems in an in vitro bone model

    International Nuclear Information System (INIS)

    The use of absorbable implant materials for fixation after bone fracture helps to avoid a second surgery for implant removal and the risks and costs involved. Magnesium (Mg) is well known as a potential metallic material for degradable implants. The aim of the present in vitro study was to evaluate if degradable LAE442-based magnesium plate–screw-systems are suitable candidates for osteosynthesis implants in load-bearing bones. The corrosion behaviour was tested concerning the influence of different surface treatments, coatings and screw torques. Steel plates and screws of the same size served as control. Plates without special treatment screwed on up to a specified torque of 15 cNm or 7 cNm, NaOH treated plates (15 cNm), magnesium fluoride coated plates (15 cNm) and steel plates as control (15 cNm) were examined in pH-buffered, temperature-controlled SBF solution for two weeks. The experimental results indicate that the LAE442 plates and screws coated with magnesium fluoride revealed a lower hydrogen evolution in SBF solution as well as a lower weight loss and volume decrease in μ-computed tomography (μCT). The nanoindentation and SEM/EDX measurements at several plate areas showed no significant differences. Summarized, the different screw torques did not affect the corrosion behaviour differently. Also the NaOH treatment seemed to have no essential influence on the degradation kinetics. The plates coated with magnesium fluoride showed a decreased corrosion rate. Hence, it is recommended to consider this coating for the next in vivo study. - Highlights: • Mg-based plate screw systems were examined in an in vitro corrosion setup. • Different screw torques did not affect the corrosion behaviour. • Pretreatment with NaOH showed no increase in corrosion resistance. • Fluoride coating slowed down the corrosion rate of plates. • Fluoride coating might be an alternative for decrease of corrosion rate in vivo

  14. Degradation behaviour of LAE442-based plate–screw-systems in an in vitro bone model

    Energy Technology Data Exchange (ETDEWEB)

    Wolters, Leonie [Small Animal Clinic, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, 30559 Hannover (Germany); Besdo, Silke [Institute of Continuum Mechanics, Leibniz Universität Hannover, Appelstraße 11, 30167 Hannover (Germany); Angrisani, Nina [Small Animal Clinic, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, 30559 Hannover (Germany); Wriggers, Peter [Institute of Continuum Mechanics, Leibniz Universität Hannover, Appelstraße 11, 30167 Hannover (Germany); Hering, Britta [Institute of Production Engineering and Machine Tools, Leibniz Universität Hannover, An der Universität 2, 30823 Garbsen (Germany); Seitz, Jan-Marten [Institute of Materials Science, Leibniz Universität Hannover, An der Universität 2, 30823 Garbsen (Germany); Reifenrath, Janin, E-mail: janin.reifenrath@tiho-hannover.de [Small Animal Clinic, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, 30559 Hannover (Germany)

    2015-04-01

    The use of absorbable implant materials for fixation after bone fracture helps to avoid a second surgery for implant removal and the risks and costs involved. Magnesium (Mg) is well known as a potential metallic material for degradable implants. The aim of the present in vitro study was to evaluate if degradable LAE442-based magnesium plate–screw-systems are suitable candidates for osteosynthesis implants in load-bearing bones. The corrosion behaviour was tested concerning the influence of different surface treatments, coatings and screw torques. Steel plates and screws of the same size served as control. Plates without special treatment screwed on up to a specified torque of 15 cNm or 7 cNm, NaOH treated plates (15 cNm), magnesium fluoride coated plates (15 cNm) and steel plates as control (15 cNm) were examined in pH-buffered, temperature-controlled SBF solution for two weeks. The experimental results indicate that the LAE442 plates and screws coated with magnesium fluoride revealed a lower hydrogen evolution in SBF solution as well as a lower weight loss and volume decrease in μ-computed tomography (μCT). The nanoindentation and SEM/EDX measurements at several plate areas showed no significant differences. Summarized, the different screw torques did not affect the corrosion behaviour differently. Also the NaOH treatment seemed to have no essential influence on the degradation kinetics. The plates coated with magnesium fluoride showed a decreased corrosion rate. Hence, it is recommended to consider this coating for the next in vivo study. - Highlights: • Mg-based plate screw systems were examined in an in vitro corrosion setup. • Different screw torques did not affect the corrosion behaviour. • Pretreatment with NaOH showed no increase in corrosion resistance. • Fluoride coating slowed down the corrosion rate of plates. • Fluoride coating might be an alternative for decrease of corrosion rate in vivo.

  15. Replacement screws valve operating under Trunnion; Substituicao de parafusos de valvulas Trunnion em regime de operacao

    Energy Technology Data Exchange (ETDEWEB)

    Souza Netto, Charles de; Santos, Rogerio Andre Zolin dos; Arnhold, Diego [Companhia de Gas do Estado do Rio Grande do Sul (SULGAS), Porto Alegre, RS (Brazil); Jacques, Rodrigo das Neves [Guidotti e Vieira Manutencao Industrial Ltda., Canoas, RS (Brazil)

    2012-07-01

    The report shows the process created for the substitution and extraction of bearing screws of the Trunnion valves, in operation. The methodology was developed at the 'Companhia de Gas do Estado do Rio Grande do Sul - SULGAS', with the objective of avoiding failure emergency situations, and or sudden breaking of the screws of fixation of the lid of the inferior bearing of the Trunnion valves. it is a preventive process of substitution of these screws, that after a great period of use in atmospheres with high potential of oxidation present structural failure. The breaking of these components creates a leaking process by the inferior lid of the valves, fact that is intended to be avoided with the application of the technical procedure of this report, guaranteeing the integrity of the valves that are vital components for the continuous operation of the gas pipe line. (author)

  16. The role of reduction and internal fixation of Lisfranc fracture–dislocations: a systematic review of the literature

    Science.gov (United States)

    Stavlas, Panagiotis; Roberts, Craig S.; Xypnitos, Fragiskos N.

    2010-01-01

    A systematic review of the literature was performed in order to evaluate the role of reduction and internal fixation in the management of Lisfranc joint fracture–dislocations. Articles were extracted from the Pubmed database and the retrieved reports were included in the study only if pre-specified eligibility criteria were fulfilled. Eleven articles were eligible for the final analysis, reporting data for the management of 257 patients. Injuries of the first three metatarsal rays were treated by closed reduction and internal fixation with screws in 16.3% of the patients, open reduction and internal fixation with screws in 66.5% and open reduction and internal fixation with Kirschner wires (K-wires) in 17.1% of the patients. The preferred method for the stabilisation of the fourth and fifth metatarsal rays was K-wires. Screw-related complications were common and were reported in 16.1% of the cases. The mean American Orthopaedic Foot and Ankle Society midfoot score was 78.1 points. Post-traumatic radiographic arthritis was reported in 49.6% of the patients, but only in 7.8% of them it was severe enough to warrant an arthrodesis. We conclude that open reduction and internal fixation of the first three metatarsal rays with screws is a reliable method for the management of Lisfranc injuries. This can be complemented by K-wires application in the fourth and fifth metatarsal rays if needed. PMID:20683593

  17. 中空加压螺钉及带旋髂深血管髂骨移位对青壮年股骨颈骨折髋关节功能恢复的影响%Effect of canulate compression bone screws and iliac bone flap with deep iliac circumflex vessel on functional restoration of hip joint after femoral neck fracture of young people

    Institute of Scientific and Technical Information of China (English)

    袁宏伟; 叶应荣

    2002-01-01

    Objective To retrospect therapeutic effects of iliac flap with deep iliac circumflex vessel with canulate compression bone screws internal fixation on femoral neck fracture of young people. Method 34 cases of femoral neck fracture had been treated with pedicle bone flap with deep iliac circumflex artery and canulate bone screws internal fixation. Result By follow-up for 1 to 1.5 years, 32 cases were healing by first intention, and patients obtained satisfactory joint function. Conclusion Femoral neck fracture can be treated by transplanting pedicle bone flap with deep iliac circumflex vessel and canulate bone screws internal fixation.

  18. Guide to radiation fixatives

    International Nuclear Information System (INIS)

    This report identifies and then characterizes a variety of substances available in the market place for potential effectiveness as a fixative on radiologically contaminated surfaces. The substances include both generic chemicals and proprietary products. In selecting a fixative for a particular application, several attributes of the fixative may be relevant to the choice. These attributes include: toxicity, durability, and cleanliness and removability. In addition to the attributes of the fixative, one should also take into account certain characteristics of the site to be treated. These characteristics relate to climate, nature of the surface, use to which the treated surface will be put, subsequent cleanup operations, and type of neighboring surfaces. Finally, costs and potential environmental effects may influence the decision. A variety of fixatives are evaluated with respect to these various attributes and summarized in a reference table

  19. In vivo degradation of a new concept of magnesium-based rivet-screws in the minipig mandibular bone.

    Science.gov (United States)

    Schaller, Benoit; Saulacic, Nikola; Beck, Stefan; Imwinkelried, Thomas; Goh, Bee Tin; Nakahara, Ken; Hofstetter, Willy; Iizuka, Tateyuki

    2016-12-01

    Self-tapping of magnesium screws in hard bone may be a challenge due to the limited torsional strength of magnesium alloys in comparison with titanium. To avoid screw failure upon implantation, the new concept of a rivet-screw was applied to a WE43 magnesium alloy. Hollow cylinders with threads on the outside were expanded inside drill holes of minipig mandibles. During the expansion with a hexagonal mandrel, the threads engaged the surrounding bone and the inside of the screw transformed into a hexagonal screw drive to allow further screwing in or out of the implant. The in vivo degradation of the magnesium implants and the performance of the used coating were studied in a human standard-sized animal model. Four magnesium alloy rivet-screws were implanted in each mandible of 12 minipigs. Six animals received the plasmaelectrolytically coated magnesium alloy implants; another six received the uncoated magnesium alloy rivet-screws. Two further animals received one titanium rivet-screw each as control. In vivo radiologic examination was performed at one, four, and eight weeks. Euthanasia was performed for one group of seven animals (three animals with coated, three with uncoated magnesium alloy implants and one with titanium implant) at 12weeks and for the remaining seven animals at 24weeks. After euthanasia, micro-computed tomography and histological examination with histomorphometry were performed. Significantly less void formation as well as higher bone volume density (BV/TV) and bone-implant contact area (BIC) were measured around the coated implants compared to the uncoated ones. The surface coating was effective in delaying degradation despite plastic deformation. The results showed potential for further development of magnesium hollow coated screws for bone fixation. PMID:27612710

  20. A new adhesive technique for internal fixation in midfacial surgery

    Directory of Open Access Journals (Sweden)

    Riediger Dieter

    2008-05-01

    Full Text Available Abstract Background The current surgical therapy of midfacial fractures involves internal fixation in which bone fragments are fixed in their anatomical positions with osteosynthesis plates and corresponding screws until bone healing is complete. This often causes new fractures to fragile bones while drilling pilot holes or trying to insert screws. The adhesive fixation of osteosynthesis plates using PMMA bone cement could offer a viable alternative for fixing the plates without screws. In order to achieve the adhesive bonding of bone cement to cortical bone in the viscerocranium, an amphiphilic bone bonding agent was created, analogous to the dentin bonding agents currently on the market. Methods The adhesive bonding strengths were measured using tension tests. For this, metal plates with 2.0 mm diameter screw holes were cemented with PMMA bone cement to cortical bovine bone samples from the femur diaphysis. The bone was conditioned with an amphiphilic bone bonding agent prior to cementing. The samples were stored for 1 to 42 days at 37 degrees C, either moist or completely submerged in an isotonic NaCl-solution, and then subjected to the tension tests. Results Without the bone bonding agent, the bonding strength was close to zero (0.2 MPa. Primary stability with bone bonding agent is considered to be at ca. 8 MPa. Moist storage over 42 days resulted in decreased adhesion forces of ca. 6 MPa. Wet storage resulted in relatively constant bonding strengths of ca. 8 MPa. Conclusion A new amphiphilic bone bonding agent was developed, which builds an optimizied interlayer between the hydrophilic bone surface and the hydrophobic PMMA bone cement and thus leads to adhesive bonding between them. Our in vitro investigations demonstrated the adhesive bonding of PMMA bone cement to cortical bone, which was also stable against hydrolysis. The newly developed adhesive fixing technique could be applied clinically when the fixation of osteosynthesis plates

  1. Fixation Options for the Volar Lunate Facet Fracture: Thinking Outside the Box.

    Science.gov (United States)

    Harness, Neil G

    2016-03-01

    Background Fractures of the distal radius with small volar ulnar marginal fracture fragments are difficult to stabilize with standard volar locking plates. The purpose of this study is to describe alternative techniques available to stabilize these injuries. Materials and Methods Five patients were identified retrospectively with unstable volar lunate facet fracture fragments treated with supplemental fixation techniques. The demographic data, pre- and postoperative radiographic parameters, and early outcomes data were analyzed. The AO classification, preoperative and final postoperative ulnar variance, articular step-off, volar tilt, radial inclination, and teardrop angle were measured. The lunate subsidence and length of the volar cortex available for fixation were measured from the initial injury films. Description of Technique Lunate facet fixation was based on the morphology of the fragment, and stabilization was achieved with headless compression screws in three patients, a tension band wire construct in one, and two cortical screws in another. Results Five patients with a mean age of 58 years (range: 41-82) were included. There were two AO C3.2 and three B3.3 fractures. Preoperative radiographic measurements including radial inclination, tilt, and ulnar variance all improved after surgery and were maintained within normal limits at 3-month follow-up. There was no change in the teardrop angle at final follow-up (70-64 degrees; p = 0.14). None of the patients had loss of fixation or volar carpal subluxation. The mean visual analog scale pain score at 3 months was 1 (range: 0-2). Conclusions The morphology of volar lunate facet fracture fragments is variable, and fixation must be customized to the particular pattern. Small fragments may preclude the use of plates and screws for fixation. These fractures can be managed successfully with tension band wire constructs and headless screws. These low-profile implants may decrease the risk of tendon

  2. The stainless steel screw as an orthopaedic implant

    Energy Technology Data Exchange (ETDEWEB)

    Rozman, J. [ITIS d. o. o. Ljubljana, Centre for Implantable Technology and Sensors Lepi pot 11, 1001 Ljubljana (Slovenia); Kmetic, M. [Institute of Materials and Technology Lepi pot 11, University of Ljubljana, 1001 Ljubljana (Slovenia); Bunc, M. [School of Medicine, Institute of Pathophysiology, Zaloska 4, 1001 Ljubljana (Slovenia); Pihlar, B. [Faculty of Chemistry and Chemical Technology, Askerceva 5, 1000 Ljubljana (Slovenia)

    2002-12-01

    The study reported here dealt with the metallographical inspection and analysis of corrosion behavior of screws for mild Slipped Capital Femoral Epiphysis (SCFE), which is a serious orthopedical problem in early adolescence. The screws were fabricated from low carbon, austenitic grade stainless steel type 316L (AISI) with 1600 ppm of nitrogen (316LN2). They were clinically tested in a nearly 25-year-long study where patients in early adolescence were operated with these screws with the fixation in situ. Since the results obtained in all patients were similar, we present the results obtained in screws removed after 3 years of implantation from a 14-year-old boy. Metallographical inspection results reveal that a low content of carbon in the SS 316LN2, and annealing this material at a high temperature ensures the monophasic microstructure of austenitic grains. In the grains twin bands that appeared during mechanical deformation were observed. As the hardness measured at the stalk (262 HV) was lower than that measured at the head of the screw (293 HV) it was concluded that cold mechanical deformation of the head was much more extensive than that of the stalk. Accordingly, corrosion of the head could be more probable than that of the stalk. Corrosion behavior of the screw in simulated physiological media (0.9% NaCl solution), carried out by the electrochemical method, gave an E{sub corr} of -0.124 V (vs. SCE), corrosion current density of 21 nA/cm{sup 2}, and corrosion rate of 0.010 {+-} 0.005 mpy. This low corrosion rate indicates that SS 316LN2 expresses relatively high corrosion resistance in a saline solution. However, potentiodynamic polarization measurements, where the specimen was driven to more than 1.8 V above the E{sub corr.}, showed that in the region between -0.1 and 0.15 V the specimen corroded, while around 0.2 V a small valley appeared where passivation proceeded. The narrow passive region between 0.15 and 0.25 V indicated that chlorides prevented the

  3. STUDY OF MANAG EMENT OF EXTRACAPSULAR FRACTURE OF NECK OF FEMUR BY DYNAMIC HIP SCREW

    Directory of Open Access Journals (Sweden)

    Kishore Roy

    2014-01-01

    Full Text Available INTRODUCTION: Increased incidence of trochanteric fractures is a direct sequalae of ageing population. Treatment of trochantric fractures with internal fixation will have an added advantage of early mobilization and ambulation besides nursing care for fragile and suppl e individuals. The dynamic hip screw is one of the very simple , affordable device and surgically not a demanding procedure. The present study was undertaken to assess the utility of DHS as a useful method in the management of extracapsular fractures. MATERIALS AND METHODS: This is a prospective study undertaken to evaluate the effectiveness of dynamic hip screw fixation device in the management of extra capsular fracture neck of femur at ASRAM Medical College Hospital , Eluru during the periodbetween Ma y 2008 and October 2010.Thirty patients with stable extracapsular fracture neck of femurtreated with dynamic hip screw fixation were selected for the present study. RESULTS: The final outcome was excellent in 16 patients , good in 10 patients , fair in 3 pati ents and poor in 1 patient. CONCLUSION: From this study we conclude that DHS is a good implant for the treatment of EVANS type - 1 Extra capsular factures neck of femur. Because it enhances fracture stability and union with controlled collapse

  4. An Articulating Tool for Endoscopic Screw Delivery

    OpenAIRE

    Petrzelka, Joseph Edward; Menon, Manas C.; Stefanov-Wagner, Clara J.; Agarwal, Suresh K.; Chatzigeorgiou, Dimitrios; Lustrino, Michelle E.; Slocum, Alexander H.

    2010-01-01

    This paper describes the development of an articulating endoscopic screw driver that can be used to place screws in osteosynthetic plates during thoracoscopic surgery. The device is small enough to be used with a 12 mm trocar sleeve and transmits sufficient torque to fully secure bone screws. The articulating joint enables correct screw alignment at obtuse angles, up to 60 deg from the tool axis. A novel articulating joint is presented, wherein a flexible shaft both transmits torque and actua...

  5. Screw insertion in trabecular bone causes peri-implant bone damage.

    Science.gov (United States)

    Steiner, Juri A; Ferguson, Stephen J; van Lenthe, G Harry

    2016-04-01

    Secure fracture fixation is still a major challenge in orthopedic surgery, especially in osteoporotic bone. While numerous studies have investigated the effect of implant loading on the peri-implant bone after screw insertion, less focus has been put on bone damage that may occur due to the screw insertion process itself. Therefore, the aim of this study was to localize and quantify peri-implant bone damage caused by screw insertion. We used non-invasive three-dimensional micro-computed tomography to scan twenty human femoral bone cores before and after screw insertion. After image registration of the pre- and post-insertion scans, changes in the bone micro-architecture were identified and quantified. This procedure was performed for screws with a small thread size of 0.3mm (STS, N=10) and large thread size of 0.6mm (LTS, N=10). Most bone damage occurred within a 0.3mm radial distance of the screws. Further bone damage was observed up to 0.6mm and 0.9mm radial distance from the screw, for the STS and LTS groups, respectively. While a similar amount of bone damage was found within a 0.3mm radial distance for the two screw groups, there was significantly more bone damage for the LTS group than the STS group in volumes of interest between 0.3-0.6mm and 0.6-0.9mm. In conclusion, this is the first study to localize and quantify peri-implant bone damage caused by screw insertion based on a non-invasive, three-dimensional, micro-CT imaging technique. We demonstrated that peri-implant bone damage already occurs during screw insertion. This should be taken into consideration to further improve primary implant stability, especially in low quality osteoporotic bone. We believe that this technique could be a promising method to assess more systematically the effect of peri-implant bone damage on primary implant stability. Furthermore, including peri-implant bone damage due to screw insertion into patient-specific in silico models of implant-bone systems could improve the

  6. Biomechanical comparison of pedicle screws versus spinous process screws in C2 vertebra A cadaveric study

    OpenAIRE

    Guan-yi Liu; Lu Mao; Rong-ming Xu; Wei-hu Ma

    2014-01-01

    Background: Biomechanical studies have shown C2 pedicle screw to be the most robust in insertional torque and pullout strength. However, C2 pedicle screw placement is still technically challenging. Smaller C2 pedicles or medial localization of the vertebral artery may preclude safe C2 pedicle screw placement in some patients. The purpose of this study was to compare the pullout strength of spinous process screws with pedicle screws in the C2. Materials and Methods: Eight fresh human cadav...

  7. Absorbable scaphoid screw development: a comparative study on biomechanics

    Directory of Open Access Journals (Sweden)

    Wang Y

    2016-04-01

    Full Text Available Yi Wang, Muguo Song, Yongqing Xu, Xiaoqing He, YueLiang Zhu Department of Orthopedic Surgery, Kunming General Hospital, Chengdu Military Command, People’s Liberation Army, Kunming, Yunnan, People’s Republic of China Background: The scaphoid is critical for maintaining the stability and movement of the wrist joints. This study aimed to develop a new internal fixator absorbable scaphoid screw (ASS for fixation of the scaphoid waist after fracture and to test the biomechanical characteristics of ASS.Materials and methods: An ASS was prepared using polylactic acids and designed based on scaphoid measurements and anatomic features. Twenty fractured scaphoid waist specimens were randomly divided into experimental and control groups (n=10/group. Reduction and internal fixation of the scaphoid were achieved with either Kirschner wires (K-wires or ASS. A moving target simulator was used to test palmar flexion and dorsal extension, with the range of testing (waist movement set from 5° of palmar flexion to 25° of dorsal extension. Flexion and extension were repeated 2,000 times for each specimen. Fracture gap displacements were measured with a computerized tomography scanning. Scaphoid tensile and bending strengths were measured by using a hydraulic pressure biomechanical system.Results: Prior to biomechanical fatigue testing, fracture gap displacements were 0.16±0.02 mm and 0.22±0.02 mm in the ASS and K-wire groups, respectively. After fatigue testing, fracture gap displacements in the ASS and the K-wire groups were 0.21±0.03 mm and 1.52±0.07 mm, respectively. The tensile strengths for the ASS and K-wire groups were 0.95±0.02 MPa and 0.63±0.02 MPa, respectively.Conclusion: Fixation using an ASS provided sufficient mechanical support for the scaphoid after fracture. Keywords: absorbable scaphoid screw, biomechanics, internal fixator, Kirschner wires

  8. Comparison of Routine Fixation of Tissues with Rapid Tissue Fixation

    OpenAIRE

    Tripathi, Meenakshi; Bansal, Rani; Gupta, Mamta; Bharat, Vinay

    2013-01-01

    Introduction: Conventional formalin-fixed, paraffin-embedded tissue provides superior cellular morphology and long-term storage. Problems with formalin fixation comprise delay of fixation and variations in the duration of fixation. Microwave assisted tissue fixation removes the use of noxious and potentially toxic formalin that decreases the turnaround time and creates a personnel friendly workflow.

  9. Slotted headless screws -- Metric series

    CERN Document Server

    International Organization for Standardization. Geneva

    1972-01-01

    Specifies the dimensions for diameters from 1 mm up to and including 10 mm; refers to ISO/R 888 for length, and to ISO/R 262 for thread series; for the different shapes and dimensions of screw ends no reference has been made.

  10. Designs and Techniques That Improve the Pullout Strength of Pedicle Screws in Osteoporotic Vertebrae: Current Status

    Directory of Open Access Journals (Sweden)

    Thomas M. Shea

    2014-01-01

    Full Text Available Osteoporosis is a medical condition affecting men and women of different age groups and populations. The compromised bone quality caused by this disease represents an important challenge when a surgical procedure (e.g., spinal fusion is needed after failure of conservative treatments. Different pedicle screw designs and instrumentation techniques have been explored to enhance spinal device fixation in bone of compromised quality. These include alterations of screw thread design, optimization of pilot hole size for non-self-tapping screws, modification of the implant’s trajectory, and bone cement augmentation. While the true benefits and limitations of any procedure may not be realized until they are observed in a clinical setting, axial pullout tests, due in large part to their reproducibility and ease of execution, are commonly used to estimate the device’s effectiveness by quantifying the change in force required to remove the screw from the body. The objective of this investigation is to provide an overview of the different pedicle screw designs and the associated surgical techniques either currently utilized or proposed to improve pullout strength in osteoporotic patients. Mechanical comparisons as well as potential advantages and disadvantages of each consideration are provided herein.

  11. Fixation versus hemiarthroplasty for undisplaced intracapsular hip fractures.

    Science.gov (United States)

    Parker, Martyn J; White, Andrew; Boyle, Adrian

    2008-07-01

    The conventional treatment for an undisplaced intracapsular hip fracture is internal fixation. A possible alternative treatment is replacement hemiarthroplasty. We have compared the outcomes of an age, sex and co-morbidity matched cohort of 346 patients who have had their undisplaced intracapsular hip fracture treated using cannulated screws with a group of 346 patients who have had a displaced intracapsular fracture treated using a hemiarthroplasty. Patients treated by internal fixation had a shorter operation time (43 versus 67 min), reduced orthopaedic ward stay (11 versus 15 days), lower incidence of peri-operative complications (24 versus 81), and a lower 1-year mortality (19% versus 26%). Additional benefits for the fixation group were less pain at 1 year, less reduction in mobility and lower dependence on walking aids. All these differences were statistically significant. Hemiarthroplasty had a lower re-admission rate (43 versus 14 cases) and re-operation rate (59 versus 22 cases). These results support the use of internal fixation for undisplaced intracapsular fractures and confirm that the final outcome for an undisplaced intracapsular hip fracture is significantly better than for a displaced intracapsular fracture, despite a higher re-operation rate after internal fixation. PMID:18407277

  12. Assessment of sagittal split ramus osteotomy rigid internal fixation techniques using a finite element method.

    Science.gov (United States)

    Albougha, S; Darwich, K; Darwich, M A; Albogha, M H

    2015-07-01

    In this study, finite element analysis (FEA) was used to evaluate nine rigid internal fixation techniques for sagittal split ramus osteotomy. To achieve this, a computed tomography (CT) scan of a healthy patient was obtained and used to generate the geometry of a half-mandible. The geometries of bicortical screws, miniplates, and monocortical screws were designed and combined with the mandible in nine models simulating various techniques. Four models used bicortical screws in various arrangements and four used miniplates of various designs. One model represented a hybrid technique. A load of 500 N was applied to the posterior teeth and FEA was applied. The most stable techniques were the hybrid technique and a single straight miniplate, presenting the least displacement among all models. Bicortical screws, while presenting reasonable stability, showed high strain areas near the anterior ramus ridge, superoposterior to the screws, implying a risk of bone fracture in this area. On the other hand, the T-shaped and double Y-shaped miniplates were associated with high von Mises stresses that would impair their rigidity, especially where angles appeared in their designs. We recommend the use of a single straight miniplate because it provides sufficient stable fixation with minimal risks or disadvantages. PMID:25766461

  13. Metallurgical examination of gun barrel screws

    Energy Technology Data Exchange (ETDEWEB)

    Bird, E.L.; Clift, T.L.

    1996-06-01

    The examination was conducted to determine the extent of degradation that had occurred after a series of firings; these screws prevent live rounds of ammunition from being loaded into the firing chamber. One concern is that if the screw tip fails and a live round is accidentally loaded into the chamber, a live round could be fired. Another concern is that if the blunt end of the screw begins to degrade by cracking, pieces could become small projectiles during firing. All screws used in firing 100 rounds or more exhibited some degree degradation, which progressively worsened as the number of rounds fired increased. (SEM, metallography, x-ray analysis, and microhardness were used.) Presence of cracks in these screws after 100 fired rounds is a serious concern that warrants the discontinued use of these screws. The screw could be improved by selecting an alloy more resistant to thermal and chemical degradation.

  14. Long-Term Follow-Up Results of Delayed Fixation of Femoral Neck Fractures in Adults

    Directory of Open Access Journals (Sweden)

    Asghar Elmi

    2013-01-01

    Full Text Available Background: Femoral neck fractures are urgent injuries that require precise reduction and stable fixation. In some cases, however, early treatment is not possible.Objectives: The present study aimed to evaluate long-term results of delayed fixation of femoral neck fractures using cannulated screws.Patients and Methods: This retrospective descriptive-analytical study was conducted on 26 patients with femoral neck fractures. The patients were treated through a closed reduction and fixation method using cannulated screws. Patients were followed up for at least five years and the rate of complications was determined.Results: In this study, 26 patients with mean age of 34.3 years were assessed. Average time interval from injury to surgery was 46.4 ± 12.2 hours; 18 patients (69% were operated on with more than 36 hours of delay. Incidence of AVN and nonunion was reported in 10 (38.4% and 3 (11.5% patients, respectively.Conclusions: Time plays an important role in treatment results of femoral neck fractures. To treat the fractures, closed reduction and fixation using cannulated screws may still be the best option.

  15. Negative pressure wound therapy and external fixation device: a simple way to seal the dressing.

    Science.gov (United States)

    Bulla, Antonio; Farace, Francesco; Uzel, André-Pierre; Casoli, Vincent

    2014-07-01

    Negative pressure therapy is widely applied to treat lower limb trauma. However, sealing a negative pressure dressing in the presence of an external fixation device may be difficult and time consuming. Therefore, screws, pins, wires, etc, may preclude the vacuum, preventing the plastic drape to perfectly adhere to the foam. To maintain the vacuum, we tried to prevent air leaking around the screws putting bone wax at the junction between the pins and the plastic drape. This solution, in our hands, avoids air leakage and helps maintain vacuum in a fast and inexpensive way. PMID:24296597

  16. Treatment of Gustilo grade Ⅲ leg fractures by external fixation associated with limited internal fixation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chun-qiang; ZHENG Hong-yu; WANG Bing; HUANG He; HE Fei; ZHAO Xue-ling

    2010-01-01

    Objective: To explore the clinical ef-fects of external fixation associated with limited internal fixa-tion on treatment of Gustilo grade Ⅲ leg fractures.Methods: From July 2006 to December 2008, 40 cases of Gustilo grade Ⅲ leg fiactures were emergently treated in our unit with external fixation frames.Soft tissue injuries were grouped according to the Gustilo classification as ⅢA in 17 cases, ⅢB in 13 cases, and ⅢC in 10 cases.All the patients were debrided within 8 hours, and then fracture reposition was preformed to reestablish the leg alignment.Limited internal fixation with plates and screws were per-formed on all the Gustilo Ilia cases and 10 Gustilo ⅢB cases at the first operation.But all the Gustilo ⅢC cases and 3 Gustilo ⅢB cases who had severe soft tissue injuries and bone loss only received Vacuum-sealing drainage (VSD).Broad-spectrum antibiotics were regularly used and VSD must be especially maintained easy and smooth for one week or more after operation.Limited internal fixation and transplanted free skin flaps or adjacent musculocutaneous flaps were not used to close wounds until the conditions of the wounds had been improved.Results: The first operations were completed within 90-210 minutes (170 minutes on average).The blood trans-fusions were from 400 ml to 1500 ml (those used for anti-shock preoperatively not included).All the 40 patients in this study were followed up for 6-28 months, 20.5 months on average.The lower limb function was evaluated accord-ing to the comprehensive evaluation standards of leg func-tion one year after operation and the results of 28 cases were excellent, 9 were good and 3 were poor.Conclusion: External fixation associated with limited internal fixation to treat Gustilo grade Ⅲ leg fractures can get satisfactory early clinical therapeutic effects.

  17. Unilateral lag-screw technique for an isolated anterior 1/4 atlas fracture

    Science.gov (United States)

    Keskil, Semih; Göksel, Murat; Yüksel, Ulaş

    2016-01-01

    Study Design: Fractures of the atlas are classified based on the fracture location and associated ligamentous injury. Among patients with atlas fractures treated using external immobilization, nonunion of the fracture could be seen. Objective: Ideally, treatment strategy for an unstable atlas fracture would involve limited fixation to maintain the fracture fragments in a reduced position without restricting the range of motion (ROM) of the atlantoaxial and atlantooccipital joints. Summary of Background Data: Such a result can be established using either transoral limited internal fixation or limited posterior lateral mass fixation. However, due to high infection risk and technical difficulty, posterior approaches are preferred but none of these techniques can fully address anterior 1/4 atlas fractures such as in this case. Materials and Methods: A novel open and direct technique in which a unilateral lag screw was placed to reduce and stabilize a progressively widening isolated right-sided anterior 1/4 single fracture of C1 that was initially treated with a rigid cervical collar is described. Results: Radiological studies made after the surgery showed no implant failure, good cervical alignment, and good reduction with fusion of C1. Conclusions: It is suggested that isolated C1 fractures can be surgically reduced and immobilized using a lateral compression screw to allow union and maintain both C1-0 and C1-2 motions, and in our knowledge this is the first description of the use of a lag screw to achieve reduction of distracted anterior 1/4 fracture fragments of the C1 from a posterior approach. This technique has the potential to become a valuable adjunct to the surgeon's armamentarium, in our opinion, only for fractures with distracted or comminuted fragments whose alignment would not be expected to significantly change with classical lateral mass screw reduction. PMID:27041886

  18. The role of bone SPECT/CT in the evaluation of lumbar spinal fusion with metallic fixation devices

    DEFF Research Database (Denmark)

    Damgaard, Morten; Nimb, Lars; Madsen, Jan L

    2010-01-01

    useful to detect a lack of fixation of the pedicle screws and hence to predict instability of the fused vertebral segments. MATERIALS AND METHODS: A retrospective analysis of 9 patients who were referred to bone scintigraphy, including combined SPECT/CT, due to persistent pain or discomfort after...

  19. Freehand Thoracic Pedicle Screw Placement: Review of Existing Strategies and a Step-by-Step Guide Using Uniform Landmarks for All Levels.

    Science.gov (United States)

    Avila, Mauricio J; Baaj, Ali A

    2016-01-01

    Pedicle screw fixation in the thoracic spine presents certain challenges due to the critical regional neurovascular anatomy as well as the narrow pedicular corridor that typically exists. With increased awareness of the dangers of intraoperative radiation, the ability to place pedicle screws with anatomic landmarks alone is paramount. In this study, we reviewed the literature from 1990 to 2015 for studies that included freehand pedicle screw placement in the thoracic spine with special emphasis on entry points and the trajectories of the screws. We excluded studies that used fluoroscopy guidance, navigation techniques, cadaveric and biomechanical articles, case reports, and experimental studies on animals. The search retrieved 40 articles, and after careful selection, seven articles were analyzed. Over 8,000 screws were placed in the different studies. The mean accuracy for placement of the thoracic screws was 93.3%. However, there is little consensus between studies in entry points, sagittal, and axial trajectories of the screws. We complete this review by presenting our step-by-step technique for the placement of freehand pedicle screws in the thoracic spine. PMID:27014535

  20. New method for fixation point of tibialis posterior tendon transfer

    OpenAIRE

    Yeganeh, Ali; Motaghi, Arash; Shahhoseini, Gholamreza; Farahini, Hosein

    2013-01-01

    Background The transfer of the tibialis posterior tendon to the dorsum of foot can restore the function of theparalyzed dorsiflexor muscles of the foot and ankle. In order to reduce the wound complication in the insertionsite of tendon to bone by a plantar knop we used a new method of fixation by an absorbable screw inserted dorsally. Methods we performed this operation on 15 patients in a 3 years period. All patients had drop foot deformitydue to irreversible lesions of the peroneal nerve. T...

  1. Absorbable scaphoid screw development: a comparative study on biomechanics

    Science.gov (United States)

    Wang, Yi; Song, Muguo; Xu, Yongqing; He, Xiaoqing; Zhu, YueLiang

    2016-01-01

    Background The scaphoid is critical for maintaining the stability and movement of the wrist joints. This study aimed to develop a new internal fixator absorbable scaphoid screw (ASS) for fixation of the scaphoid waist after fracture and to test the biomechanical characteristics of ASS. Materials and methods An ASS was prepared using polylactic acids and designed based on scaphoid measurements and anatomic features. Twenty fractured scaphoid waist specimens were randomly divided into experimental and control groups (n=10/group). Reduction and internal fixation of the scaphoid were achieved with either Kirschner wires (K-wires) or ASS. A moving target simulator was used to test palmar flexion and dorsal extension, with the range of testing (waist movement) set from 5° of palmar flexion to 25° of dorsal extension. Flexion and extension were repeated 2,000 times for each specimen. Fracture gap displacements were measured with a computerized tomography scanning. Scaphoid tensile and bending strengths were measured by using a hydraulic pressure biomechanical system. Results Prior to biomechanical fatigue testing, fracture gap displacements were 0.16±0.02 mm and 0.22±0.02 mm in the ASS and K-wire groups, respectively. After fatigue testing, fracture gap displacements in the ASS and the K-wire groups were 0.21±0.03 mm and 1.52±0.07 mm, respectively. The tensile strengths for the ASS and K-wire groups were 0.95±0.02 MPa and 0.63±0.02 MPa, respectively. Conclusion Fixation using an ASS provided sufficient mechanical support for the scaphoid after fracture. PMID:27217756

  2. Posterior Spinal Reconstruction with Pedicle Screws, Multiple Iliac Screws and Wisconsin Spinal Wires in a Patient with Neurofibromatosis Scoliosis: A Case Report.

    Science.gov (United States)

    Kim, Woong-Beom; Park, Young-Seop; Park, Jong-Hwa; Hyun, Seung-Jae

    2015-09-01

    A 54-year-old female with neurofibromatosis type 1 presented with progressing truncal shift owing to spinal deformity. On plain radiograph, the Cobb angle was 54 degree in coronal plane. Radiological examinations showed severe dystrophic change with dysplastic pedicles, bony scalloping, neural foraminal widening from dural ectasia. The patient underwent deformity correction and reconstruction surgery from the T9 to the pelvis using multiple iliac screws and Wisconsin interspinous segmental instrumentation by wiring due to maximize fixation points. The postoperative course was uneventful. One-year follow-up radiographs showed a successful curve correction with solid fusion. We report a case of pedicle dysplasia and dystrophic change treated by posterior segmental spinal instrumentation and fusion with help of multiple iliac screws and modified Wisconsin interspinous segmental wiring. PMID:26512279

  3. Assessment of a percutaneous iliosacral screw insertion simulator

    CERN Document Server

    Tonetti, J; Girard, P; Dubois, M; Merloz, P; Troccaz, Jocelyne; 10.1016/j.otsr.2009.07.005

    2009-01-01

    BACKGROUND: Navigational simulator use for specialized training purposes is rather uncommon in orthopaedic and trauma surgery. However, it reveals providing a valuable tool to train orthopaedic surgeons and help them to plan complex surgical procedures. PURPOSE: This work's objective was to assess educational efficiency of a path simulator under fluoroscopic guidance applied to sacroiliac joint percutaneous screw fixation. MATERIALS AND METHODS: We evaluated 23 surgeons' accuracy inserting a guide-wire in a human cadaver experiment, following a pre-established procedure. These medical trainees were defined in three prospective respects: novice or skilled; with or without theoretical knowledge; with or without surgical procedure familiarity. Analysed criteria for each tested surgeon included the number of intraoperative X-rays taken in order to achieve the surgical procedure as well as an iatrogenic index reflecting the surgeon's ability to detect any hazardous trajectory at the time of performing said procedu...

  4. Screw-fed pump system

    Science.gov (United States)

    Sprouse, Kenneth M

    2014-11-25

    A pump system includes a pump that includes a first belt and a second belt that are spaced apart from each other to provide generally straight sides of a passage there between. There is an inlet at one end of the passage and an outlet at an opposite end of the passage, with a passage length that extends between the inlet and the outlet. The passage defines a gap distance in a width direction between the straight sides at the passage inlet. A hopper includes an interior space that terminates at a mouth at the passage inlet. At least one screw is located within the interior space of the hopper and includes a screw diameter in the width direction that is less than or equal to the gap distance.

  5. Biomechanical failure of metacarpal fracture resorbable plate fixation.

    Science.gov (United States)

    Lionelli, Gerald T; Korentager, Richard A

    2002-08-01

    Metacarpal fractures are a relatively common hand injury that may require operative intervention to ensure adequate reduction and stabilization. The use of permanent hardware, although acceptable, may lead to complications and an increased number of surgical procedures. The use of resorbable hardware such as poly-L-lactic acid and polyglycolic acid copolymer plates and screws may circumvent some of these complications. In vitro studies have demonstrated that the biomechanical characteristics of these resorbable plates may provide the rigid fixation necessary to allow for union of metacarpal fractures in vivo. However, limited clinical data are available regarding the success of their use in this application. The authors present what they believe is the first reported case of the failure of a poly-L-lactic acid and polyglycolic acid copolymer miniplate after use in the fixation of a metacarpal shaft fracture. PMID:12187350

  6. Clinical efficacy of open reduction and semirigid internal fixation in management of displaced pediatric mandibular fractures: A series of 10 cases and surgical guidelines

    Directory of Open Access Journals (Sweden)

    Samir Joshi

    2015-01-01

    Full Text Available Aim: To evaluate the efficacy of open reduction and semirigid internal fixation in the management of displaced pediatric mandibular fractures. Method: Ten patients with displaced mandibular fractures treated with 1.5 mm four holed titanium mini-plate and 4 mm screws which were removed within four month after surgery. Results: All cases showed satisfactory bone healing without any growth disturbance. Conclusion: Open reduction and rigid internal fixation (ORIF with 1.5 mm titanium mini- plates and 4 mm screws is a reliable and safe method in treatment of displaced paediatric mandibular fractures.

  7. Biomechanical testing of the LCP--how can stability in locked internal fixators be controlled?

    Science.gov (United States)

    Stoffel, Karl; Dieter, Ulrich; Stachowiak, Gwidon; Gächter, André; Kuster, Markus S

    2003-11-01

    New plating techniques, such as non-contact plates, have been introduced in acknowledgment of the importance of biological factors in internal fixation. Knowledge of the fixation stability provided by these new plates is very limited and clarification is still necessary to determine how the mechanical stability, e.g. fracture motion, and the risk of implant failure can best be controlled. The results of a study based on in vitro experiments with composite bone cylinders and finite element analysis using the Locking Compression Plate (LCP) for diaphyseal fractures are presented and recommendations for clinical practice are given. Several factors were shown to influence stability both in compression and torsion. Axial stiffness and torsional rigidity was mainly influenced by the working length, e.g. the distance of the first screw to the fracture site. By omitting one screw hole on either side of the fracture, the construct became almost twice as flexible in both compression and torsion. The number of screws also significantly affected the stability, however, more than three screws per fragment did little to increase axial stiffness; nor did four screws increase torsional rigidity. The position of the third screw in the fragment significantly affected axial stiffness, but not torsional rigidity. The closer an additional screw is positioned towards the fracture gap, the stiffer the construct becomes under compression. The rigidity under torsional load was determined by the number of screws only. Another factor affecting construct stability was the distance of the plate to the bone. Increasing this distance resulted in decreased construct stability. Finally, a shorter plate with an equal number of screws caused a reduction in axial stiffness but not in torsional rigidity. Static compression tests showed that increasing the working length, e.g. omitting the screws immediately adjacent to the fracture on both sides, significantly diminished the load causing plastic

  8. Magnetic resonance imaging of poly-L-lactic acid interference screws after anterior cruciate ligament reconstruction

    International Nuclear Information System (INIS)

    This study investigated the reaction around the poly-L-lactic acid (PLLA) interference screws implanted for graft fixation in anterior cruciate ligament (ACL) reconstruction using the magnetic resonance imaging (MRI). Twenty-two patients (four males and 18 females, average age 28 years old) followed for more than six months after ACL reconstruction using bone patellar tendon bone graft were evaluated. The average duration of follow up was 14 months. PLLA interference screws were used for graft fixation. MRI scans were performed in all patients. Clinical results were good. Lysholm score was 95 points on average, and Lachman test was (-) in 15 cases, (±) in five cases, (+) in two cases. On MRI scans, three patients showed wide high signal intensity around the PLLA screws. In the three patients the mean Lysholm score was 93 points, two patients showed negative Lachman test, and one showed (+). We could not detect any relation between clinical results and the high signal area on MRI in this study. (author)

  9. Feasibility of C2 Vertebra Screws Placement in Patient With Occipitalization of Atlas: A Tomographic Study.

    Science.gov (United States)

    Ji, Wei; Liu, Xiang; Huang, Wenhan; Huang, Zucheng; Li, Xueshi; Chen, Jianting; Wu, Zenghui; Zhu, Qingan

    2015-09-01

    Occipitalization of atlas (OA) is a congenital disease with the possibility of anomalous bony anatomies and the C2 pedicle screw insertion is technically challenging. However, there are no existing literatures clarified the dimensions and angulations of the C2 pedicles, lamina and lateral masses for screw insertion in patients with OA. Therefore, the aim of this study was to assess the morphometric features of C2 for screw placement in OA to guide the use of surgical screws. Measurements of the OA patients on the computer tomography (CT) images including lamina angle, length and thickness, pedicle angle, length and thickness, and lateral mass thickness and length of the axis vertebra. The OA patients data were compared with age and gender matched cohort of randomly selected patients in a control group without OA. The picture archiving and communication system was used for all patients who had received cervical CT scanning between January 2001 and January 2015. Measurements were performed independently by 2 experienced observers who reviewed the CT scans and recorded the patients with OA. Statistical analysis was performed at a level of significance P mass, no value was bigger than 12 mm in the OA group, whereas 40% of the values in the control group were bigger than 12 mm. The average pedicle and laminar angles were 37° and 49° in the patients with OA, respectively. The variable anatomy in patients with OA needs to be taken into account when performing spinal stabilization as the C2 bony architectures are significantly smaller than normal. Anatomically, translaminar screw is a more viable option in comparison with pedicle screw for C2 fixation in OA. Nevertheless, the suitability should be fully assessed prior to surgery. PMID:26376390

  10. Screw Placement Accuracy and Outcomes Following O-Arm-Navigated Atlantoaxial Fusion: A Feasibility Study.

    Science.gov (United States)

    Smith, Jacob D; Jack, Megan M; Harn, Nicholas R; Bertsch, Judson R; Arnold, Paul M

    2016-06-01

    Study Design Case series of seven patients. Objective C2 stabilization can be challenging due to the complex anatomy of the upper cervical vertebrae. We describe seven cases of C1-C2 fusion using intraoperative navigation to aid in the screw placement at the atlantoaxial (C1-C2) junction. Methods Between 2011 and 2014, seven patients underwent posterior atlantoaxial fusion using intraoperative frameless stereotactic O-arm Surgical Imaging and StealthStation Surgical Navigation System (Medtronic, Inc., Minneapolis, Minnesota, United States). Outcome measures included screw accuracy, neurologic status, radiation dosing, and surgical complications. Results Four patients had fusion at C1-C2 only, and in the remaining three, fixation extended down to C3 due to anatomical considerations for screw placement recognized on intraoperative imaging. Out of 30 screws placed, all demonstrated minimal divergence from desired placement in either C1 lateral mass, C2 pedicle, or C3 lateral mass. No neurovascular compromise was seen following the use of intraoperative guided screw placement. The average radiation dosing due to intraoperative imaging was 39.0 mGy. All patients were followed for a minimum of 12 months. All patients went on to solid fusion. Conclusion C1-C2 fusion using computed tomography-guided navigation is a safe and effective way to treat atlantoaxial instability. Intraoperative neuronavigation allows for high accuracy of screw placement, limits complications by sparing injury to the critical structures in the upper cervical spine, and can help surgeons make intraoperative decisions regarding complex pathology. PMID:27190736

  11. Degradation behaviour of LAE442-based plate-screw-systems in an in vitro bone model.

    Science.gov (United States)

    Wolters, Leonie; Besdo, Silke; Angrisani, Nina; Wriggers, Peter; Hering, Britta; Seitz, Jan-Marten; Reifenrath, Janin

    2015-04-01

    The use of absorbable implant materials for fixation after bone fracture helps to avoid a second surgery for implant removal and the risks and costs involved. Magnesium (Mg) is well known as a potential metallic material for degradable implants. The aim of the present in vitro study was to evaluate if degradable LAE442-based magnesium plate-screw-systems are suitable candidates for osteosynthesis implants in load-bearing bones. The corrosion behaviour was tested concerning the influence of different surface treatments, coatings and screw torques. Steel plates and screws of the same size served as control. Plates without special treatment screwed on up to a specified torque of 15cNm or 7cNm, NaOH treated plates (15cNm), magnesium fluoride coated plates (15cNm) and steel plates as control (15cNm) were examined in pH-buffered, temperature-controlled SBF solution for two weeks. The experimental results indicate that the LAE442 plates and screws coated with magnesium fluoride revealed a lower hydrogen evolution in SBF solution as well as a lower weight loss and volume decrease in μ-computed tomography (μCT). The nanoindentation and SEM/EDX measurements at several plate areas showed no significant differences. Summarized, the different screw torques did not affect the corrosion behaviour differently. Also the NaOH treatment seemed to have no essential influence on the degradation kinetics. The plates coated with magnesium fluoride showed a decreased corrosion rate. Hence, it is recommended to consider this coating for the next in vivo study. PMID:25686954

  12. Primary internal fixation and soft-tissue reconstruction in the treatment for an open Lisfranc fracture-dislocation.

    Science.gov (United States)

    Sanli, Ilknur; Hermus, Joris; Poeze, Martijn

    2012-06-01

    The importance of anatomical reduction for improved outcome has been recognised in the management of Lisfranc injuries. Operative fixation is indicated in case of dislocation or unstable ligamentous injury, because discongruity of the Lisfranc joint can lead to deleterious functional outcome. Screws are the recommended method of fixation of the medial en middle column, and K-wires are used for stabilisation of the unstable lateral column. Primary arthrodesis can provide advantages in pure ligamentous injury. In the management of complex open Lisfranc fractures, external fixation with K-wires can be used, but often results in a high percentage of arc deformities and functional limitations. In recent years, there is a progressive change from external to internal fixation in primary stabilisation of open fractures. This case report describes the treatment for a grade III open Lisfranc fracture-dislocation by use of primary internal fixation and soft-tissue reconstruction. PMID:21706153

  13. An augmented fixation method for distal fibular fractures in elderly patients: a biomechanical evaluation.

    Science.gov (United States)

    Dunn, Warren R; Easley, Mark E; Parks, Brent G; Trnka, Hans-Jörg; Schon, Lew C

    2004-03-01

    This biomechanical investigation compared two fixation techniques for distal fibular fractures. Elderly cadaver lower extremities with simulated fibula fractures underwent fixation either with a plate and intramedullary Kirschner wires (K-wires) with or without the addition of three screws inserted through the four cortices of the fibula and the tibia. The specimens were axially loaded to body weight on a materials testing machine, and the supinated foot was externally rotated to failure. Displacement at the fracture site was monitored with an extensometer. Comparing the augmented technique with the technique without additional screws, mean stiffness was 460 +/- 100 and 320 +/- 200 N-mm/deg, strength at failure was 31 +/- 10 and 19 +/- 7 N-m, strength at 30 degrees external rotation was 15 +/- 5 and 10 +/- 6 N-m, and axial deformation was 0.04 +/- 0.06 mm and 0.10 +/- 0.04 mm, respectively. All differences were statistically significant. PMID:15006332

  14. Radionuclides fixation by hydroxyapatite

    International Nuclear Information System (INIS)

    Some characteristic results on strontium fixation by coprecipitation and sorption with hydroxyapatite are presented. Coprecipitation experiments performed at wide range of experimental conditions have confirmed that strontium incorporated into hydroxyapatite by isomorphous substitution of calcium. Adsorption on the surface of well crystallized hydroxyapatite follows Langmuir's adsorption isotherm with monolayer capacity of 1.5 10-4 mol/g. (author)

  15. Rotational Efficiency of Photo-Driven Archimedes Screws for Micropumps

    OpenAIRE

    Chih-Lang Lin; Yu-Sheng Lin; Baldeck, Patrice L.

    2015-01-01

    In this study, we characterized the rotational efficiency of the photo-driven Archimedes screw. The micron-sized Archimedes screws were fabricated using the two-photon polymerization technique. Free-floating screws trapped by optical tweezers align in the laser irradiation direction and rotate spontaneously. The influences of the screw pitch and the number of screw blades have been investigated in our previous studies. In this paper, the blade thickness and the central rod of the screw were ...

  16. Application of intermediate screw technology on thoracolumbar fractures%经伤椎椎弓根置钉技术在胸腰段骨折中的应用

    Institute of Scientific and Technical Information of China (English)

    吕豪珍; 林红; 张绍昆; 闫明; 刘理迪

    2012-01-01

    BACKGROUND: For thoracolumbar fractures, there are a lot of fixed ways, however, at present intermediate screws in shortsegment pedicular fixation is minimal damage, cost less, and fixed tightly.OBJECTIVE: To systemic illustrate the technology of intermediate screw and clinical application effect.METHODS: A computer-based online search was performed on PuMed database and CNKI database with key words of"Intermediate screws, pedicular screw fixation, thoracolumbar fracture" in English and Chinese from January 1983 to June 2011.Repeated literatures were eliminated.RESULTS AND CONCLUSION: A total of 48 articles were included to review. Biological mechanics experimental and clinicalapplication result indicates that intermediate screws in short segment pedicular fixation can instantly reset vertebral fracture,restore vertebral body height, and compared with the traditional short segments of the posterior fixation, intermediate screws inshort segment pedicular fixation can effectively reduce the incidence of complications of internal fixation loose or screw breakage,vertebral height lost again.%背景:对于胸腰椎骨折,有很多固定方式,但目前经伤椎后路短节段内固定是损伤最小、费用较少,且固定牢固的固定方式.目的:系统阐述伤椎置钉技术的发展及其临床应用效果.方法:应用计算机检索1983-01/2011-06 PubMed数据库、中国知网数据库中相关文章,中文检索词为"伤椎置钉,椎弓根螺钉内固定,胸腰段骨折",英文检索词为"intermediate screws,pedicular screw fixation,thoracolumbar fracture".排除重复文献.结果与结论:共纳入48篇文献进行综述.目前,生物力学实验及临床应用结果证明,经伤椎短节段椎弓根螺钉内固定能即时复位骨折椎体,恢复椎体高度,且同传统的后路短节段内固定相比,能有效地降低内固定松动或短钉、伤椎高度再次丢失等并发症的发生率.

  17. A COMPARATIVE STUDY BETWEEN DYNAMIC HIP SCREW AND PRIMARY HEMIARTHROPLASTY IN TROCHANTERIC FRACTURE O F FEMUR IN ELDERY

    OpenAIRE

    Prasanta Kumar; Dibakar; Mrinal Kanti; Fagu Ram; Amalendu Bikash

    2013-01-01

    ABSTRACT : Hip fractures, particularly in older persons, resul t in problems that extend far beyond the orthopedic injury, with repercussions in t he areas of medicine , rehabilitation, psychiatry, social work, and health care economics. The degree of osteoporosis may influence fracture type. For these reasons, the treatment of i ntertrochanteric fractures is operative. Our propose of the study to compare the result of dyn amic hip screw fixation and hemiarthr...

  18. Only fixation for cervical spondylosis: Report of early results with a preliminary experience with 6 cases

    OpenAIRE

    Atul Goel

    2013-01-01

    Aim: The author reports early post-operative outcome and preliminary experience with an alternative form of treatment of cervical degenerative or spondylotic disease leading to spinal canal stenosis that involves fixation-arthrodesis of the affected spinal segment using one or two (double insurance) transarticular screws for each joint. Materials and Methods: During the period of months from March 2013 to July 2013, six patients having cervical spondylotic cord compression were treated with t...

  19. Navicular stress fractures treated with minimally invasive fixation

    Directory of Open Access Journals (Sweden)

    Korula Mani Jacob

    2013-01-01

    Early intervention with minimally invasive surgery has significantly less morbidity and a reliable early return to active sports and is therefore the best option in high-performance athletes. Materials and Methods: Nine athletes with ten stress fractures of the navicular treated at our institution between April 1991 and October 2000. The mean age of the patients was 22.8 years (range 18-50 years. All patients were treated by minimally invasive screw fixation and early weight bearing mobilization without a cast. The average followup was 7 years (range 2-11 years. Results: Seven of the nine patients returned to their pre-fracture level of sporting activity at an average of 5 months (range 3-9 months. One patient returned to full sporting activity following a delay of 2 years due to an associated tibial stress fracture and one patient had an unsatisfactory result. Long term review at an average of 7 years showed that six of these eight patients who returned to sports remained symptom free with two patients experiencing minimal intermittent discomfort after prolonged activity. Conclusions: We recommend percutaneous screw fixation as a reliable, low morbidity procedure allowing early return to full sporting activity without long term complications or recurrences.

  20. Migration pattern of cementless press fit cups in the presence of stabilizing screws in total hip arthroplasty

    Directory of Open Access Journals (Sweden)

    Zilkens C

    2011-03-01

    Full Text Available Abstract The aim of this study was to evaluate the initial acetabular implant stability and late acetabular implant migration in press fit cups combined with screw fixation of the acetabular component in order to answer the question whether screws are necessary for the fixation of the acetabular component in cementless primary total hip arthroplasty. One hundred and seven hips were available for follow-up after primary THA using a cementless, porous-coated acetabular component. A total of 631 standardized radiographs were analyzed digitally by the "single-film-x-ray-analysis" method (EBRA. One hundred 'and one (94.4% acetabular components did not show significant migration of more than 1 mm. Six (5.6% implants showed migration of more than 1 mm. Statistical analysis did not reveal preoperative patterns that would identify predictors for future migration. Our findings suggest that the use of screw fixation for cementless porous- coated acetabular components for primary THA does not prevent cup migration.

  1. Migration pattern of cementless press fit cups in the presence of stabilizing screws in total hip arthroplasty.

    Science.gov (United States)

    Zilkens, C; Djalali, S; Bittersohl, B; Kälicke, T; Kraft, C N; Krauspe, R; Jäger, Marcus

    2011-03-28

    The aim of this study was to evaluate the initial acetabular implant stability and late acetabular implant migration in press fit cups combined with screw fixation of the acetabular component in order to answer the question whether screws are necessary for the fixation of the acetabular component in cementless primary total hip arthroplasty. One hundred and seven hips were available for follow-up after primary THA using a cementless, porous-coated acetabular component. A total of 631 standardized radiographs were analyzed digitally by the "single-film-x-ray-analysis" method (EBRA). One hundred and one (94.4 %) acetabular components did not show significant migration of more than 1 mm. Six (5.6%) implants showed migration of more than 1 mm. Statistical analysis did not reveal preoperative patterns that would identify predictors for future migration. Our findings suggest that the use of screw fixation for cementless porous-coated acetabular components for primary THA does not prevent cup migration. PMID:21486725

  2. Twin screw subsurface and surface multiphase pumps

    Energy Technology Data Exchange (ETDEWEB)

    Dass, P. [CAN-K GROUP OF COMPANIES, Edmonton, Alberta (Canada)

    2011-07-01

    A new subsurface twin screw multiphase pump has been developed to replace ESP and other artificial lift technologies. This technology has been under development for a few years, has been field tested and is now going for commercial applications. The subsurface twin screw technology consists of a pair of screws that do not touch and can be run with a top drive or submersible motor; and it carries a lot of benefits. This technology is easy to install and its low slippage makes it highly efficient with heavy oil. In addition twin screw multiphase pumps are capable of handling high viscosity fluids and thus their utilization can save water when used in thermal applications. It also induces savings of chemicals because asphaltenes do not break down easily as well as a reduction in SOR. The subsurface twin screw multiphase pump presented herein is an advanced technology which could be used in thermal applications.

  3. Femoral Condyles Tangential Views: An Effective Method to Detect the Screw Penetration of Femoral Condyles After Retrograde Nailing

    Institute of Scientific and Technical Information of China (English)

    Zhan-Le Zheng; Xian Yu; Wei Chen; Yue-Ju Liu; Kun-Lun Yu; Tao Wu; Ying-Ze Zhang

    2015-01-01

    Background: Postoperative knee soft tissue irritation is a common complication after retrograde nail fixation of femoral fractures.Distal locking screw prominence is one of the causes for soft tissue irritation.This study aimed to determine whether the use of the femoral condyles tangential views improve the diagnostic accuracy compared with anteroposterior (A-P) view in detecting distal locking screw penetrations during retrograde femoral nailing.Methods: The angle between the sagittal plane and lateral aspect of the condyle and the angle between the sagittal plane and medial aspect of condyle were measured on computed tomography (CT) images.After the angles were measured and recorded, cadaveric femurs were used in a simulated surgical procedure.The retrograde femoral nail was inserted into the femur and placed distal locking screws, which were left 2, 4, and 6 mm proud of the medial and lateral condyles for each femur.A-P view, lateral condyle tangential view and medial condyle tangential view were obtained.All fluoroscopic images were recorded and sent to three observers blinded to the experimental procedure to determine whether screws penetrated the condyle cortex or not.Results: According to the results of CT scan, the lateral condyle view was 20.88 ± 0.98° and the medial condyle view was 40.46 ± 3.14°.In the A-P view, we detected 0% at 2 mm penetration, 16.7% (lateral condyle screw) and 25.0% (medial condyle screw) at 4 mm, and 41.7% (lateral condyle screw) and 58.3% (medial condyle screw) at 6 mm.In the lateral tangential view, we detected 91.7% at 2 mm penetration of the lateral condyle and 100% at 4 mm and 6 mm.In the medial tangential view, we detected 66.7% at 2 mm penetration of the medial condyle and 100% at 4 mm and 6 mm.The femoral condyle tangential views provided significant improvement in detecting screw penetrations at all lengths (2, 4, and 6 mm) compared with the A-P view (P < 0.05).Conclusions: The femoral condyles

  4. Femoral Condyles Tangential Views: An Effective Method to Detect the Screw Penetration of Femoral Condyles After Retrograde Nailing

    Directory of Open Access Journals (Sweden)

    Zhan-Le Zheng

    2015-01-01

    Full Text Available Background: Postoperative knee soft tissue irritation is a common complication after retrograde nail fixation of femoral fractures. Distal locking screw prominence is one of the causes for soft tissue irritation. This study aimed to