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Hosseinzadeh-Posti M, Kamal Z, Rajaeirad M. Exploring vertebral bone density changes in a trunk with adolescent idiopathic scoliosis: a mechanobiological modeling investigation of intact and unilaterally paralyzed muscles. Comput Methods Biomech Biomed Engin 2024:1-17. [PMID: 39105616 DOI: 10.1080/10255842.2024.2377345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 06/27/2024] [Accepted: 07/02/2024] [Indexed: 08/07/2024]
Abstract
This study aimed to elucidate the vertebral bone density variations associated with adolescent idiopathic scoliosis (AIS), specifically examining the impact of unilateral muscle paralysis using an integrated approach combining Frost's Mechanostat theory, a three-dimensional subject-specific finite element model and a musculoskeletal model of the L2 vertebra. The findings revealed a spectrum of bone density values ranging from 0.29 to 0.31 g/cm3, along with vertebral micro-strain levels spanning from 300 to 2200, consistent with existing literature. Furthermore, the ratio of maximum von Mises stress between the concave and convex side in the AIS model with intact muscles was approximately 1.08, which decreased by 4% due following unilateral paralysis of longissimus thoracis pars thoracic muscle. Overall, this investigation contributes to a deeper understanding of AIS biomechanics and lays the groundwork for future research endeavors aimed at optimizing clinical management approaches for individuals with this condition.
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Affiliation(s)
| | - Zeinab Kamal
- Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
| | - Mohadese Rajaeirad
- Department of Biomedical Engineering, Faculty of Engineering, University of Isfahan, Isfahan, 81746, Iran
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Liu W, Zang L, Kang N, Yang L, An L, Zhu W, Hai Y. Influence of configuration and anchor in ligamentous augmentation to prevent proximal junctional kyphosis: A finite element study. Front Bioeng Biotechnol 2022; 10:1014487. [DOI: 10.3389/fbioe.2022.1014487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 10/07/2022] [Indexed: 11/06/2022] Open
Abstract
Ligament augmentation has been applied during spinal surgery to prevent proximal junctional kyphosis (PJK), but the configuration and distal anchor strategies are diverse and inconsistent. The biomechanics of different ligament augmentation strategies are, therefore, unclear. We aimed to create a finite element model of the spine for segments T6–S1. Model Intact was the native form, and Model IF was instrumented with a pedicle screw from segments T10 to S1. The remaining models were based on Model IF, with ligament augmentation configurations as common (CM), chained (CH), common and chained (CHM); and distal anchors to the spinous process (SP), crosslink (CL), and pedicle screw (PS), creating SP-CH, PS-CHM, PS-CH, PS-CM, CL-CHM, CL-CH, and CL-CM models. The range of motion (ROM) and maximum stress on the intervertebral disc (IVD), PS, and interspinous and supraspinous ligaments (ISL/SSL) was measured. In the PS-CH model, the ROM for segments T9–T10 was 73% (of Model Intact). In the CL-CHM, CL-CH, CL-CM, PS-CM, and PS-CHM models, the ROM was 8%, 17%, 7%, 13%, and 30%, respectively. The PS-CH method had the highest maximum stress on IVD and ISL/SSL, at 80% and 72%, respectively. The crosslink was more preferable as the distal anchor. In the uppermost instrumented vertebrae (UIV) + 1/UIV segment, the CM was the most effective configuration. The PS-CH model had the highest flexion load on the UIV + 1/UIV segment and the CL-CM model provided the greatest reduction. The CL-CM model should be verified in a clinical trial. The influence of configuration and anchor in ligament augmentation is important for the choice of surgical strategy and improvement of technique.
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Han L, Yang H, Li Y, Li Z, Ma H, Wang C, Yuan J, Zheng L, Chen Q, Lu X. Biomechanical Evaluation of the Cross-link Usage and Position in the Single and Multiple Segment Posterior Lumbar Interbody Fusion. Orthop Surg 2022; 14:2711-2720. [PMID: 36102202 PMCID: PMC9531066 DOI: 10.1111/os.13485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 07/28/2022] [Accepted: 08/09/2022] [Indexed: 12/29/2022] Open
Abstract
OBJECTIVE Previous studies have neither explored the usage of cross-links nor investigated the optimal position of the cross-links in posterior lumbar interbody fusion (PLIF). This study evaluates biomechanical properties of cross-links in terms of different fixation segments and optimal position in single- and multi-segment posterior lumbar interbody fusion. METHODS Two finite element (FE) models of instrumented lumbosacral spine with single-(L4/5) and multi-segment (L3-S1) PLIF surgery were simulated. On the basis of the two models, the benefits of the usage of cross-links were assessed and compared with the status of no application of cross-links. Moreover, the effects of position of cross-links on multi-segment PLIF surgery were studied in Upper, Middle, and Lower positions. RESULTS No significant difference was found in the range of motion (ROM), intersegmental rotational angle (IRA) of adjacent segments, and intradiscal pressure (IDP) regardless of the usage of cross-links in the single-segment PLIF surgery, while the cross-link increased the maximum von Mises stress in the fixation (MSF) under the axial rotation (53.65 MPa vs 41.42 MPa). In the multi-segment PLIF surgery, the usage of cross-links showed anti-rotational advantages indicated by ROM (Without Cross-link 2.35o , Upper, 2.24o ; Middle, 2.26o ; Lower, 2.30o ) and IRA (Without Cross-link 1.19o , Upper, 1.08o ; Middle, 1.09o ; Lower, 1.13o ). The greatest values of MSF were found in without cross-link case under the flexion, lateral bending, and axial rotation (37.48, 62.61, and 86.73 MPa). The application of cross-links at the Middle and Lower positions had lower values of MSF (48.79 and 69.62 MPa) under the lateral bending and axial rotation, respectively. CONCLUSION The application of cross-links was not beneficial for the single-segment PLIF, while it was found highly advantageous for the multi-segment PLIF. Moreover, the usage of cross-links at the Middle or Lower positions resulted in a better biomechanical stability.
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Affiliation(s)
- Lin Han
- Department of OrthopaedicsShanghai Changzheng Hospital, Second Military Medical UniversityShanghaiChina
| | - Haisong Yang
- Department of OrthopaedicsShanghai Changzheng Hospital, Second Military Medical UniversityShanghaiChina
| | - Yongheng Li
- Biomechanics LaboratorySchool of Biological Science & Medical Engineering, Southeast UniversityNanjingChina
| | - Zhiyong Li
- Biomechanics LaboratorySchool of Biological Science & Medical Engineering, Southeast UniversityNanjingChina,School of Mechanical Medical and Process Engineering, Queensland University of TechnologyBrisbaneAustralia
| | - Hongdao Ma
- Department of OrthopaedicsShanghai Changzheng Hospital, Second Military Medical UniversityShanghaiChina
| | - Chenfeng Wang
- Department of OrthopaedicsShanghai Changzheng Hospital, Second Military Medical UniversityShanghaiChina
| | - Jincan Yuan
- Department of OrthopaedicsShanghai Changzheng Hospital, Second Military Medical UniversityShanghaiChina
| | - Luyu Zheng
- School of Medicine, Zhengzhou UniversityZhengzhouChina
| | - Qiang Chen
- Biomechanics LaboratorySchool of Biological Science & Medical Engineering, Southeast UniversityNanjingChina
| | - Xuhua Lu
- Department of OrthopaedicsShanghai Changzheng Hospital, Second Military Medical UniversityShanghaiChina
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A biomechanical investigation of lumbar interbody fusion techniques. J Mech Behav Biomed Mater 2021; 125:104961. [PMID: 34781226 DOI: 10.1016/j.jmbbm.2021.104961] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 11/01/2021] [Accepted: 11/06/2021] [Indexed: 11/24/2022]
Abstract
The anterior, posterior, transforaminal, and circumferential lumbar interbody fusions (ALIF, PLIF, TLIF, CLIF/360) are used to treat spondylolisthesis, trauma, and degenerative pathologies. This study aims to investigate the biomechanical effects of the lumbar interbody fusion techniques on the spine. A validated T12-sacrum lumbar spine finite-element model was used to simulate surgical fusion of L4-L5 segment using ALIF, PLIF with one and two cages, TLIF with unilateral and bilateral fixation, and CLIF/360. The models were simulated under pure-moment and combined (moment and compression) loadings to investigate the effect of different lumbar interbody fusion techniques on range of motion, forces transferred through the vertebral bodies, disc pressures, and endplate stresses. The range of motion of the lumbar spine was decreased the most for fusions with bilateral posterior instrumentations (TLIF, PLIF, and CLIF/360). The increase in forces transmitted through the vertebrae and increase in disc pressures were directly proportional to the range of motion. The discs superior to fusion were under higher pressure, which was attributed to adjacent segment degeneration in the superior discs. The increase in endplate stresses was directly proportional to the cross-sectional area and was greater in caudal endplates at the fusion level, which was attributed to cage subsidence. The response of the models was in line with overall clinical observations from the patients and can be further used for future studies, which aim to investigate the effect of geometrical and material variations in the spine. The model results will assist surgeons in making informed decisions when selecting fusion procedures based on biomechanical effects.
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Zhang M, Ren W, Mo Z, Li J, Pu F, Fan Y. Biomechanics of adjacent segment after three-level lumbar fusion, hybrid single-level semi-rigid fixation with two-level lumbar fusion. Comput Methods Biomech Biomed Engin 2021; 25:455-463. [PMID: 34338556 DOI: 10.1080/10255842.2021.1959557] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Multi-level spinal fusion has been reported in some cases to lead to adjacent segment disease (ASD) and proximal junctional kyphosis (PJK). The purpose of this study was to demonstrate a polyether-ether-ketone (PEEK) rod fixation system implanted adjacent to a two-level lumbar fusion would have a lower risk of PJK than three-level lumbar fusion, which was investigated by comparing the biomechanical effects on the adjacent level after surgical procedures. Four finite element (FE) models of the lumbar-sacral spine (intact model (INT), L4-S1 fusion model (L4-S1 FUS), L3-S1 fusion model (L3-S1 FUS), and single-level PEEK rod semi-rigid fixation adjacent to L4-S1 fusion model (FUSPRF)) were established. Displacement-controlled finite element (FE) analysis was used during the simulation. Compared with the two-level fusion model (L4-S1 FUS), both three-level implanted models (L3-S1 FUS and FUSPRF) showed an increase intersegmental rotation angle, and maximum von-Mises stress on the disc annulus. The results also showed that the intersegmental rotation, stress on the disc annulus and maximum stress on the rod were lower in the FUSPRF model than the L3-S1 FUS model. Though the maximum screw stress was higher in the FUSPRF model than the L3-S1 FUS model under all moments except for torsion, the maximum screw stress in the two models were far below the yield strength of titanium alloy. As the parameters above have been indicated as risk factors for PJK, it can be concluded that hybrid single-level PEEK rod semi-rigid fixation and two-level lumbar fusion have a lower risk of PJK than three-level lumbar fusion.
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Affiliation(s)
- Mingzheng Zhang
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, Key Laboratory of Neuro-functional Information and Rehabilitation Engineering of the Ministry of Civil Affairs, National Research Center for Rehabilitation Technical Aids, Beijing, P. R. China
| | - Weiyan Ren
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, Key Laboratory of Neuro-functional Information and Rehabilitation Engineering of the Ministry of Civil Affairs, National Research Center for Rehabilitation Technical Aids, Beijing, P. R. China
| | - Zhongjun Mo
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, Key Laboratory of Neuro-functional Information and Rehabilitation Engineering of the Ministry of Civil Affairs, National Research Center for Rehabilitation Technical Aids, Beijing, P. R. China
| | - Jian Li
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, Key Laboratory of Neuro-functional Information and Rehabilitation Engineering of the Ministry of Civil Affairs, National Research Center for Rehabilitation Technical Aids, Beijing, P. R. China
| | - Fang Pu
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, P. R. China
| | - Yubo Fan
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, P. R. China
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Cornaz F, Widmer J, Snedeker JG, Spirig JM, Farshad M. Cross-links in posterior pedicle screw-rod instrumentation of the spine: a systematic review on mechanical, biomechanical, numerical and clinical studies. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2020; 30:34-49. [DOI: 10.1007/s00586-020-06597-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 05/13/2020] [Accepted: 09/05/2020] [Indexed: 12/14/2022]
Abstract
Abstract
Purpose
Dorsal screw-rod instrumentations are used for a variety of spinal disorders. Cross-links (CL) can be added to such constructs, however, no clear recommendations exist. This study aims to provide an overview of the available evidence on the effectiveness of CL, potentially allowing to formulate recommendations on their use.
Methods
A systematic literature review was performed on PubMed and 37 original articles were included and grouped into mechanical, biomechanical, finite element and clinical studies. The change in range of motion (ROM) was analyzed in mechanical and biomechanical studies, ROM, stiffness and stress distribution were evaluated in finite element studies and clinical outcome parameters were analyzed in clinical studies.
Results
A relative consistent reduction in ROM in axial rotation with CL-augmentation was reported, while minor and less consistent effects were observed in flexion–extension and lateral bending. The use of CLs was clinical beneficial in C1/2 fusion, while the limited clinical studies on other anatomic regions show no significant benefit for CL-augmentation.
Conclusion
While CL provides some additional axial rotation stability in most situations, lateral bending and flexion–extension are less affected. Based on clinical data, CL-augmentation can only be recommended for C1/2 instrumentations, while for other cases, further clinical studies are needed to allow for evidence-based recommendations.
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Umale S, Yoganandan N, Kurpad SN. Development and validation of osteoligamentous lumbar spine under complex loading conditions: A step towards patient-specific modeling. J Mech Behav Biomed Mater 2020; 110:103898. [PMID: 32957203 DOI: 10.1016/j.jmbbm.2020.103898] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 05/13/2020] [Accepted: 05/30/2020] [Indexed: 01/04/2023]
Abstract
Finite-element models are used to investigate the biomechanics of normal, diseased and surgically fused spines. Generally, nominal spine geometries are used to understand the biomechanics, which has created a need for a technique that develops patient-specific lumbar spine geometries. In the current study, a lumbar spine (T12-Sacrum) was developed using a technique that facilitates geometrical morphing, which assists in incorporating patient-specific morphologies into the model. The model evaluations can be used to propose a biomechanically suitable lumbar spine fusion procedure for patients. This study focuses on the validation of the base model under pure-moment, pure-compression and combined-compression-and-moment loadings. Experimental data from the literature were used to validate the response of the model. The L1-L2, L2-L3, L3-L4, L4-L5 and L5-sacrum segments demonstrated a range of motion of 4.5, 4.0, 5.4, 5.0 and 8.9° in flexion; 3.0, 2.5, 3.6, 3.1 and 5.2° in extension; 6.2, 5.8, 6.4, 5.0 and 6.1° in right and left lateral bending; and 2.9, 3.0, 2.9, 1.9 and 2.5° in right and left axial rotation, all under 10 Nm pure-moment loading. The L1-L2, L2-L3, L3-L4, L4-L5 and L5-sacrum discs demonstrated compressions of 1.1, 1.4, 1.6, 1.4 and 0.9 mm under 1200 N follower- or pure-compression loading. With the combined loading of 280 N follower and 7.5 Nm moment, the L1-L5 model demonstrated 11.7, 7.2, 18.3 and 10.4 degrees of range of motion in flexion, extension, bending and rotation, respectively. The model results were in good agreement with corridors from six different experimental studies and can be used for future clinical studies.
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Affiliation(s)
- Sagar Umale
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, USA.
| | - Narayan Yoganandan
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, USA; Clement J. Zablocki VA Medical Center, Milwaukee, WI, USA; Center for NeuroTrauma Research, Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Shekar N Kurpad
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, USA; Clement J. Zablocki VA Medical Center, Milwaukee, WI, USA; Center for NeuroTrauma Research, Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, USA
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8
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Strains in trussed spine interbody fusion implants are modulated by load and design. J Mech Behav Biomed Mater 2018; 80:203-208. [DOI: 10.1016/j.jmbbm.2018.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 01/06/2018] [Accepted: 02/02/2018] [Indexed: 12/31/2022]
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Lopes VM, Neto MA, Amaro AM, Roseiro LM, Paulino M. FE and experimental study on how the cortex material properties of synthetic femurs affect strain levels. Med Eng Phys 2017. [DOI: 10.1016/j.medengphy.2017.06.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Wu W, Chen C, Ning J, Sun P, Zhang J, Wu C, Bi Z, Fan J, Lai X, Ouyang J. A Novel Anterior Transpedicular Screw Artificial Vertebral Body System for Lower Cervical Spine Fixation: A Finite Element Study. J Biomech Eng 2017; 139:2618332. [DOI: 10.1115/1.4036393] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Indexed: 11/08/2022]
Abstract
A finite element model was used to compare the biomechanical properties of a novel anterior transpedicular screw artificial vertebral body system (AVBS) with a conventional anterior screw plate system (ASPS) for fixation in the lower cervical spine. A model of the intact cervical spine (C3–C7) was established. AVBS or ASPS constructs were implanted between C4 and C6. The models were loaded in three-dimensional (3D) motion. The Von Mises stress distribution in the internal fixators was evaluated, as well as the range of motion (ROM) and facet joint force. The models were generated and analyzed by mimics, geomagic studio, and ansys software. The intact model of the lower cervical spine consisted of 286,382 elements. The model was validated against previously reported cadaveric experimental data. In the ASPS model, stress was concentrated at the connection between the screw and plate and the connection between the titanium mesh and adjacent vertebral body. In the AVBS model, stress was evenly distributed. Compared to the intact cervical spine model, the ROM of the whole specimen after fixation with both constructs is decreased by approximately 3 deg. ROM of adjacent segments is increased by approximately 5 deg. Facet joint force of the ASPS and AVBS models was higher than those of the intact cervical spine model, especially in extension and lateral bending. AVBS fixation represents a novel reconstruction approach for the lower cervical spine. AVBS provides better stability and lower risk for internal fixator failure compared with traditional ASPS fixation.
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Affiliation(s)
- Weidong Wu
- Department of Anatomy, Guangdong Provincial Medical Biomechanical Key Laboratory, Academy of Orthopedics of Guangdong Province, Southern Medical University, Guangzhou 510515, China
- Wuhan Concrete Technology Company Limited, Gaoxin Avenue 818, Wuhan 430200, Hubei, China e-mail:
| | - Chun Chen
- Department of Orthopedics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, Zhejiang, China e-mail:
| | - Jinpei Ning
- Department of Orthopedics, Wuzhou Red Cross Hospital, Wuzhou 543002, Guangxi, China e-mail:
| | - Peidong Sun
- Department of Anatomy, Guangdong Provincial Medical Biomechanical Key Laboratory, Academy of Orthopedics of Guangdong Province, Southern Medical University, Guangzhou 510515, China e-mail:
| | - Jinyuan Zhang
- Department of Anatomy, Guangdong Provincial Medical Biomechanical Key Laboratory, Academy of Orthopedics of Guangdong Province, Southern Medical University, Guangzhou 510515, China e-mail:
| | - Changfu Wu
- Department of Orthopedic Surgery, The Affiliated Hospital of Putian University, Putian 351100, Fujian, China
- Department of Orthopedic Surgery, The Affiliated Putian Hospital of Southern Medical University, Putian 351100, Fujian, China e-mail:
| | - Zhenyu Bi
- Department of Anatomy, Guangdong Provincial Medical Biomechanical Key Laboratory, Academy of Orthopedics of Guangdong Province, Southern Medical University, Guangzhou 510515, China e-mail:
| | - Jihong Fan
- Department of Anatomy, Guangdong Provincial Medical Biomechanical Key Laboratory, Academy of Orthopedics of Guangdong Province, Southern Medical University, Guangzhou 510515, China e-mail:
| | - Xianliang Lai
- Department of Orthopedic Surgery, Wenzhou Hospitals of Traditional Chinese and Western Medicine, Wenzhou 325000, Zhejiang, China e-mail:
| | - Jun Ouyang
- Professor Department of Anatomy, Guangdong Provincial Medical Biomechanical Key Laboratory, Academy of Orthopedics of Guangdong Province, Southern Medical University, No. 1023 Shatai Road, Baiyun District, Guangzhou 510515, China e-mail:
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Long-term effects of placing one or two cages in instrumented posterior lumbar interbody fusion. INTERNATIONAL ORTHOPAEDICS 2016; 40:1239-46. [DOI: 10.1007/s00264-016-3173-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 03/13/2016] [Indexed: 10/21/2022]
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Study of Double-level Degeneration of Lower Lumbar Spines by Finite Element Model. World Neurosurg 2016; 86:294-9. [DOI: 10.1016/j.wneu.2015.09.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 09/09/2015] [Accepted: 09/11/2015] [Indexed: 11/20/2022]
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Liu F, Feng Z, Liu T, Fei Q, Jiang C, Li Y, Jiang X, Dong J. A biomechanical comparison of 3 different posterior fixation techniques for 2-level lumbar spinal disorders. J Neurosurg Spine 2015; 24:375-80. [PMID: 26637067 DOI: 10.3171/2015.7.spine1534] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
OBJECT This study sought to make a biomechanical comparison of 3 different posterior fixation techniques for 2-level lumbar spinal disorders. METHODS Eight fresh-frozen human cadaver lumbar spines (4 from L-1 to L-5, 4 from L-1 to S-1) were tested by applying pure moments of ± 8 Nm. Each specimen was first tested intact, and then the left facetectomies of L3-4 and L4-5 were performed to establish an unstable condition without removal of discs. Three instrumentation systems were then tested randomly: unilateral pedicle screw (UPS), UPS with contralateral translaminar facet screw (UPSFS), and bilateral pedicle screw (BPS). The range of motion (ROM) and the neutral zone (NZ) of L3-5 were measured. RESULTS All fixation types could reduce the ROM of L3-5 significantly in flexion, extension, and lateral bending, compared with the intact state. In axial torsion, only BPS reduced the ROM significantly, compared with the intact state. The UPSFS technique provided intermediate stability, which was superior to the UPS in flexion-extension and lateral bending, and inferior to the BPS in lateral bending. Compared with the intact state, the NZs decreased significantly for UPS, UPSFS, and BPS in flexion-extension, while not significantly in lateral bending and axial torsion. CONCLUSIONS In this study, among the 3 fixation techniques, BPS offered the highest stability, UPSFS provided intermediate stability, and UPS was the least stable for 2-level lumbar spinal disorders. UPSFS appeared to be able to offer a less invasive choice than BPS in well-selected patients with 2-level lumbar spinal disorders.
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Affiliation(s)
- Fubing Liu
- Department of Orthopaedics, Zhongshan Hospital of Fudan University; and
| | - Zhenzhou Feng
- Department of Orthopaedics, Zhongshan Hospital of Fudan University; and
| | - Tianze Liu
- Department of Orthopaedics, Zhongshan Hospital of Fudan University; and
| | - Qinming Fei
- Department of Orthopaedics, Zhongshan Hospital of Fudan University; and
| | - Chun Jiang
- Department of Orthopaedics, Zhongshan Hospital of Fudan University; and
| | - Yuanchao Li
- Institute of Biomedical Production and Life Quality Program, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaoxing Jiang
- Department of Orthopaedics, Zhongshan Hospital of Fudan University; and
| | - Jian Dong
- Department of Orthopaedics, Zhongshan Hospital of Fudan University; and
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Alizadeh M, Kadir MRA, Fadhli MM, Fallahiarezoodar A, Azmi B, Murali MR, Kamarul T. The use of X-shaped cross-link in posterior spinal constructs improves stability in thoracolumbar burst fracture: a finite element analysis. J Orthop Res 2013; 31:1447-54. [PMID: 23640802 DOI: 10.1002/jor.22376] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 04/01/2013] [Indexed: 02/04/2023]
Abstract
Posterior instrumentation is a common fixation method used to treat thoracolumbar burst fractures. However, the role of different cross-link configurations in improving fixation stability in these fractures has not been established. A 3D finite element model of T11-L3 was used to investigate the biomechanical behavior of short (2 level) and long (4 level) segmental spine pedicle screw fixation with various cross-links to treat a hypothetical L1 vertebra burst fracture. Three types of cross-link configurations with an applied moment of 7.5 Nm and 200 N axial force were evaluated. The long construct was stiffer than the short construct irrespective of whether the cross-links were used (p < 0.05). The short constructs showed no significant differences between the cross-link configurations. The XL cross-link provided the highest stiffness and was 14.9% stiffer than the one without a cross-link. The long construct resulted in reduced stress to the adjacent vertebral bodies and screw necks, with 66.7% reduction in bending stress on L2 when the XL cross-link was used. Thus, the stability for L1 burst fracture fixation was best achieved by using long segmental posterior instrumentation constructs and an XL cross-link configuration. Cross-links did not improved stability when a short structure was used.
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Affiliation(s)
- Mina Alizadeh
- Medical Implant Technology Group (MEDITEG), Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia
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Lo CC, Tsai KJ, Zhong ZC, Chen SH, Hung C. Biomechanical differences of Coflex-F and pedicle screw fixation combined with TLIF or ALIF – a finite element study. Comput Methods Biomech Biomed Engin 2011; 14:947-56. [DOI: 10.1080/10255842.2010.501762] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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