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Zhao G, He S, Chen E, Ma T, Wu K, Wu J, Li W, Song C. Biomechanical effects of osteoporosis severity on the occurrence of proximal junctional kyphosis following long-segment posterior thoracolumbar fusion. Clin Biomech (Bristol, Avon) 2023; 110:106132. [PMID: 37924756 DOI: 10.1016/j.clinbiomech.2023.106132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 10/17/2023] [Accepted: 10/23/2023] [Indexed: 11/06/2023]
Abstract
BACKGROUND Proximal junctional kyphosis is a common long-term complication in adult spinal deformity surgery that involves long-segment posterior spinal fusion. However, the underlying biomechanical mechanisms of the impact of osteoporosis on proximal junctional kyphosis remain unclear. The present study was to evaluate adjacent segment degeneration and spine mechanical instability in osteoporotic patients who underwent long-segment posterior thoracolumbar fusion. METHODS Finite element models of the thoracolumbar spine T1-L5 with posterior long-segment T8-L5 fusion under different degrees of osteoporosis were constructed to analyze intervertebral disc stress characterization, vertebrae mechanical transfer, and pedicle screw system loads during various motions. FINDINGS Compared with normal bone mass, the maximum von Mises stresses of T7 and T8 were increased by 20.32%, 22.38%, 44.69%, 4.49% and 29.48%, 17.84%, 40.95%, 3.20% during flexion, extension, lateral bending, and axial rotation in the mild osteoporosis model, and by 21.21%, 18.32%, 88.28%, 2.94% and 37.76%, 15.09%, 61.47%, -0.04% in severe osteoporosis model. The peak stresses among T6/T7, T7/T8, and T8/T9 discs were 14.77 MPa, 11.55 MPa, and 2.39 MPa under lateral bending conditions for the severe osteoporosis model, respectively. As the severity of osteoporosis increased, stress levels on SCR8 and SCR9 intensified during various movements. INTERPRETATION Osteoporosis had an adverse effect on proximal junctional kyphosis. The stress levels in cortical bone, intervertebral discs and screws were increased with bone mass loss, which can easily lead to intervertebral disc degeneration, bone destruction as well as screw pullout. These factors have significantly affected or accelerated the occurrence of proximal junctional kyphosis.
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Affiliation(s)
- Gaiping Zhao
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, PR China.
| | - Shenglan He
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, PR China
| | - Eryun Chen
- School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, PR China
| | - Tong Ma
- Department of Bone and Joint Surgery, Yangpu Hospital, School of Medicine, Tongji University, Shanghai 200090, China
| | - Kunneng Wu
- Shanghai Institute of Medical Device Testing, Shanghai 201318, China
| | - Jie Wu
- Key Laboratory of Hydrodynamics, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Weiqi Li
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, PR China
| | - Chengli Song
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, PR China
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Zeng Q, Liao Y, Pou K, Chen Q, Li Y, Cai L, Huang Z, Tang S. Does Lumbar Interbody Fusion Modality Affect the Occurrence of Complications in an Osteoporotic Spine Under Whole-Body Vibration? A Finite Element Study. World Neurosurg 2023; 176:e297-e305. [PMID: 37224957 DOI: 10.1016/j.wneu.2023.05.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 05/15/2023] [Indexed: 05/26/2023]
Abstract
OBJECTIVE To evaluate the effects of 3 lumbar interbody fusion techniques on the occurrence of complications in an osteoporotic spine under whole-body vibration. METHODS A previously developed and validated nonlinear finite element model of L1-S1was modified to develop anterior lumbar interbody fusion (ALIF), posterior lumbar interbody fusion (PLIF), and transforaminal lumbar interbody fusion (TLIF) models with osteoporosis. In each model, the lower surface of the sacrum was absolutely fixed, a follower load of 400N was applied through the axis of the lumbar spine, and an axial sinusoidal vertical load of ±40N (5 Hz) was imposed on the superior surface of L1, to perform a transient dynamic analysis. The maximal values of intradiscal pressure, shear stress on annulus substance, disc bulge, facet joint stress, and screw and rod stress, along with their dynamic response curves, were collected. RESULTS Among these 3 models, the TLIF model generated the greatest screw and rod stress, and the PLIF model generated the greatest cage-bone interface stress. At the L3-L4 level, compared with the other 2 models, the maximal values and dynamic response curves of intradiscal pressure, shear stress of annulus ground substance, and disc bulge were all lower in the ALIF model. However, the facet contact stress at the adjacent segment in the ALIF model was higher than that in the other 2 models. CONCLUSIONS In an osteoporotic spine under whole-body vibration, TLIF has the highest risk of screw and rod breakage, PLIF has the highest risk of cage subsidence, and ALIF has the lowest risk of upper adjacent disc degeneration, but the highest risk of adjacent facet joint degeneration.
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Affiliation(s)
- Qiuhong Zeng
- School of Chinese medicine, Jinan University, Guangzhou, China
| | - Yi Liao
- School of Chinese medicine, Jinan University, Guangzhou, China
| | - Kuokchon Pou
- School of Chinese medicine, Jinan University, Guangzhou, China
| | - Qian Chen
- School of Chinese medicine, Jinan University, Guangzhou, China
| | - Yixuan Li
- School of Chinese medicine, Jinan University, Guangzhou, China
| | - Lulu Cai
- School of Chinese medicine, Jinan University, Guangzhou, China
| | - Zhen Huang
- School of Chinese medicine, Jinan University, Guangzhou, China
| | - Shujie Tang
- School of Chinese medicine, Jinan University, Guangzhou, China.
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Biomechanical and clinical studies on lumbar spine fusion surgery: a review. Med Biol Eng Comput 2023; 61:617-634. [PMID: 36598676 DOI: 10.1007/s11517-022-02750-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 12/22/2022] [Indexed: 01/05/2023]
Abstract
Low back pain is associated with degenerative disc diseases of the spine. Surgical treatment includes fusion and non-fusion types. The gold standard is fusion surgery, wherein the affected vertebral segment is fused. The common complication of fusion surgery is adjacent segment degeneration (ASD). The ASD often leads to revision surgery, calling for a further fusion of adjacent segments. The existing designs of nonfusion type implants are associated with clinical problems such as subsidence, difficulty in implantation, and the requirement of revision surgeries. Various surgical approaches have been adopted by the surgeons to insert the spinal implants into the affected segment. Over the years, extensive biomechanical investigations have been reported on various surgical approaches and prostheses to predict the outcomes of lumbar spine implantations. Computer models have been proven to be very effective in identifying the best prosthesis and surgical procedure. The objective of the study was to review the literature on biomechanical studies for the treatment of lumbar spinal degenerative diseases. A critical review of the clinical and biomechanical studies on fusion spine surgeries was undertaken. The important modeling parameters, challenges, and limitations of the current studies were identified, showing the future research directions.
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Du X, Zhou Y, Li L, Persson C, Ferguson SJ. The porous cantilever beam as a model for spinal implants: Experimental, analytical and finite element analysis of dynamic properties. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2023; 20:6273-6293. [PMID: 37161106 DOI: 10.3934/mbe.2023270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Investigation of the dynamic properties of implants is essential to ensure safety and compatibility with the host's natural spinal tissue. This paper presents a simplified model of a cantilever beam to investigate the effects of holes/pores on the structures. Free vibration test is one of the most effective methods to measure the dynamic response of a cantilever beam, such as natural frequency and damping ratio. In this study, the natural frequencies of cantilever beams made of polycarbonate (PC) containing various circular open holes were investigated numerically, analytically, and experimentally. The experimental data confirmed the accuracy of the natural frequencies of the cantilever beam with open holes calculated by finite element and analytical models. In addition, two finite element simulation methods, the dynamic explicit and modal dynamic methods, were applied to determine the damping ratios of cantilever beams with open holes. Finite element analysis accurately simulated the damped vibration behavior of cantilever beams with open holes when known material damping properties were applied. The damping behavior of cantilever beams with random pores was simulated, highlighting a completely different relationship between porosity, natural frequency and damping response. The latter highlights the potential of finite element methods to analyze the dynamic response of arbitrary and complex structures, towards improved implant design.
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Affiliation(s)
- Xiaoyu Du
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Yijun Zhou
- Division of Biomedical Engineering, Uppsala University, Uppsala, Sweden
| | - Lingzhen Li
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
- Institute of Structural Engineering, ETH Zurich, Zurich, Switzerland
| | - Cecilia Persson
- Division of Biomedical Engineering, Uppsala University, Uppsala, Sweden
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Zhang C, Guo LX. Effect of whole-body vibration at different frequencies on the lumbar spine: A finite element study based on a whole human body model. Proc Inst Mech Eng H 2022; 236:1752-1761. [DOI: 10.1177/09544119221135688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Many previous studies have found that occupational drivers commonly suffered from low back pain, and low back pain and degeneration of the intervertebral disc might be associated with vibration conditions. However, the biomechanical mechanisms of whole-body vibration that caused pain and injury were not clear. In this study, a validated whole human body finite element model was used, and vibration loads at frequencies of 3, 5, 7 and 9 Hz were loaded to evaluate the frequency effects on the spine. The results showed that the responses of the spine were strong at the 5 Hz vibration load. Vibration loads would produce alternating stresses and bulges in the annulus fibrosus and change the direction of the pressure in the nucleus pulposus. The posterior region of the intervertebral disc showed greater stress fluctuations than the anterior region. The Risk Factors showed that long-term exposure to whole-body vibrations at 5 and 7 Hz might have greater adverse effects on the spine. The findings of this study confirmed that vibrations near the resonance frequency of the human body would cause more injuries to the spine than other frequencies. Alternating stress and bulge might cause fatigue and the degeneration of the intervertebral disc, which might be the mechanisms of spinal injury caused by whole-body vibration, and the posterior regions of the intervertebral disc were more susceptible to degeneration. Some appropriate measures should be taken to reduce the adverse effects of whole-body vibration on spinal health.
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Affiliation(s)
- Chi Zhang
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
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Zhu J, Shen H, Cui Y, Fogel GR, Liao Z, Liu W. Biomechanical Evaluation of Transforaminal Lumbar Interbody Fusion with Coflex-F and Pedicle Screw Fixation: Finite Element Analysis of Static and Vibration Conditions. Orthop Surg 2022; 14:2339-2349. [PMID: 35946442 PMCID: PMC9483060 DOI: 10.1111/os.13425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 07/02/2022] [Accepted: 07/02/2022] [Indexed: 12/29/2022] Open
Abstract
OBJECTIVE To investigate the biomechanics of transforaminal lumbar interbody fusion (TLIF) with interspinous process device (IPD) or pedicle screw fixation under both static and vibration conditions by the finite element (FE) method. METHOD A validated FE model of the L1-5 lumbar spine was used in this study. This FE model derived from computed tomography images of a healthy female adult volunteer of appropriate age. Then the model was modified to simulate L3-4 TLIF. Four conditions were compared: (i) intact; (ii) TLIF combined with bilateral pedicle screw fixation (BPSF); (iii) TLIF combined with U-shaped IPD Coflex-F (CF); and (iv) TLIF combined with unilateral pedicle screw fixation (UPSF). The intact and surgical FE models were analyzed under static and vibration loading conditions respectively. For static loading conditions, four motion modes (flexion, extension, lateral bending, and axial rotation) were simulated. For vibration loading conditions, the dynamic responses of lumbar spine under sinusoidal vertical load were simulated. RESULT Under static loading conditions, compared with intact case, BPSF decreased range of motion (ROM) by 92%, 95%, 89% and 92% in flexion, extension, lateral bending and axial rotation, respectively. While CF decreased ROM by 87%, 90%, 69% and 80%, and UPSF decreased ROM by 84%, 89%, 66% and 82%, respectively. Compared with CF, UPSF increased the endplate stress by 5%-8% in flexion, 7%-10% in extension, 2%-4% in lateral bending, and decreased the endplate stress by 16%-19% in axial rotation. Compared with CF, UPSF increased the cage stress by 9% in flexion, 10% in extension, and decreased the cage stress by 3% in lateral bending, and 13% in axial rotation. BPSF decreased the stress responses of endplates and cage compared with CF and UPSF. Compared BPSF, CF decreased the facet joint force (FJF) by 6%-13%, and UPSF decreased the FJF by 4%-12%. During vibration loading conditions, compared with BPSF, CF reduced maximum values of the FJF by 16%-32%, and vibration amplitudes by 22%-35%, while UPSF reduced maximum values by 20%-40%, and vibration amplitudes by 31%-45%. CONCLUSION Compared with other surgical models, BPSF increased the stability of lumbar spine, and also showed advantages in cage stress and endplate stress. CF showed advantages in IDP and FJF especially during vertical vibration, which may lead to lower risk of adjacent segment degeneration. CF may be an effective alternative to pedicle screw fixation in TLIF procedures.
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Affiliation(s)
- Jia Zhu
- Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhenChina,Department of Mechanical EngineeringTsinghua UniversityBeijingChina,Biomechanics and Biotechnology LabResearch Institute of Tsinghua University in ShenzhenShenzhenChina
| | - Hangkai Shen
- Department of Mechanical EngineeringTsinghua UniversityBeijingChina,Biomechanics and Biotechnology LabResearch Institute of Tsinghua University in ShenzhenShenzhenChina
| | - Yangyang Cui
- Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhenChina,Department of Mechanical EngineeringTsinghua UniversityBeijingChina,Biomechanics and Biotechnology LabResearch Institute of Tsinghua University in ShenzhenShenzhenChina
| | | | - Zhenhua Liao
- Biomechanics and Biotechnology LabResearch Institute of Tsinghua University in ShenzhenShenzhenChina
| | - Weiqiang Liu
- Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhenChina,Department of Mechanical EngineeringTsinghua UniversityBeijingChina,Biomechanics and Biotechnology LabResearch Institute of Tsinghua University in ShenzhenShenzhenChina
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Liu Z, Zhang S, Li J, Tang H. Biomechanical comparison of different interspinous process devices in the treatment of lumbar spinal stenosis: a finite element analysis. BMC Musculoskelet Disord 2022; 23:585. [PMID: 35715775 PMCID: PMC9204899 DOI: 10.1186/s12891-022-05543-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 06/08/2022] [Indexed: 11/10/2022] Open
Abstract
Background Lumbar spinal stenosis (LSS) is a common disease among elderly individuals, and surgery is an effective treatment. The development of minimally invasive surgical techniques, such as the lumbar interspinous process device (IPD), has provided patients with more surgical options. Objective To investigate the biomechanical properties of different IPDs, including BacFuse, X-Stop and Coflex, in the treatment of LSS. Methods Based on the computed tomography images of a patient with LSS, four finite element (FE) models of L3-S5 were created in this study. The FE models included a surgical model of the intact lumbar spine and surgical models of the lumbar IPDs BacFuse, X-Stop, and Coflex. After validating the models, they were simulated for four physiological motions: flexion, extension, lateral bending and axial rotation, and range of motion (ROM). Stress distribution of discs and facet joints in each segment, stress distribution of the spinous process in the operated section, and stress distribution of the internal fixation were compared and analysed. Results Compared to the model of the intact lumbar spine, the other three models showed a decrease in ROM and disc and facet joint stresses in the surgical segment during movement and an increase in ROM and disc and facet joint stresses in the adjacent segments. These effects were greater for the proximal adjacent segment with BacFuse and more pronounced for the distal adjacent segment with Coflex, while X-Stop had the greatest stress effect on the spinous process in the surgical segment. Conclusion BacFuse, Coflex and X-Stop could all be implemented to effectively reduce extension and disc and facet joint stresses, but they also increase the ROM and disc and facet joint stresses in adjacent segments, which may cause degeneration.
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Affiliation(s)
- Zhengpeng Liu
- Department of Orthopaedics, Beijing Friendship Hospital, Capital Medical University, Xicheng District, Beijing, 101100, China.,Department of Spine Surgery, Affiliated Hospital of Chengde Medical University, Chengde, 067000, Hebei, China
| | - Shuyi Zhang
- Department of Spine Surgery, Affiliated Hospital of Chengde Medical University, Chengde, 067000, Hebei, China
| | - Jia Li
- Department of Joint Surgery, Affiliated Hospital of Chengde Medical University, Chengde, 067000, Hebei, China
| | - Hai Tang
- Department of Orthopaedics, Beijing Friendship Hospital, Capital Medical University, Xicheng District, Beijing, 101100, China.
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Yuan X, Li Y, Chen Q, Zeng Q, Pou K, Wong H, Tang S. Effect of pedicle screw fixation on adjacent segments in osteoporotic spine following transforaminal lumbar interbody fusion under whole body vibration. World Neurosurg 2022; 161:e523-e530. [DOI: 10.1016/j.wneu.2022.02.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 02/11/2022] [Accepted: 02/12/2022] [Indexed: 10/19/2022]
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Shen H, Fogel GR, Zhu J, Liao Z, Liu W. Biomechanical analysis of lumbar fusion with proximal interspinous process device implantation. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3498. [PMID: 33998776 DOI: 10.1002/cnm.3498] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 03/27/2021] [Accepted: 05/14/2021] [Indexed: 06/12/2023]
Abstract
Lumbar spinal fusion may cause adjacent segment degeneration (ASD) in the long term. Recently, inserting an interspinous process device (IPD) proximal to the fusion has been proposed to prevent ASD. The aim of this study was to investigate the biomechanics of lumbar fusion with proximal IPD implantation (LFPI) under both static loads and whole body vibration (WBV). A previously validated finite element (FE) model of the L1-5 lumbar spine was modified to simulate L4-5 fusion. Three different IPDs (Coflex-F, Wallis and DIAM) were inserted at the L3-4 segment of the fusion model to construct the LFPI models. The intact and surgical FE models were analyzed under static loads and WBV, respectively. Under static loading conditions, LFPI decreased range of motion (ROM) and intradiscal pressure (IDP) at the transition segment L3-4 compared with the fusion case. At the segment (L2-3) adjacent to the transition level, LFPI induced higher motion and IDP than rigid fusion. Under WBV, vibration amplitudes of the L3-4 IDP and L4-5 facet joint force (FJF) decreased by more than 54.3% after surgery. The LFPI model with the DIAM system offered the most comparable biomechanics to the intact model under static loads, and decreased the dynamic responses of the L4-5 FJF under WBV. The LFPI model with the Wallis and Coflex-F systems could stabilize the transition segment, and decrease dynamic responses of the L3-4 IDP. The DIAM system may be more suitable in LFPI.
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Affiliation(s)
- Hangkai Shen
- Department of Mechanical Engineering, Tsinghua University, Beijing, China
- Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen, China
| | - Guy R Fogel
- Orthopedics Department, Spine Pain Begone Clinic, San Antonio, Texas, USA
| | - Jia Zhu
- Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen, China
| | - Zhenhua Liao
- Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen, China
| | - Weiqiang Liu
- Department of Mechanical Engineering, Tsinghua University, Beijing, China
- Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen, China
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Zhao G, Wu K, Liu D, Zhao J, Liang P, Hang S. A biomechanical study of proximal junctional kyphosis after posterior long segment fusion with vertebral body augmentation. Clin Biomech (Bristol, Avon) 2021; 87:105415. [PMID: 34174675 DOI: 10.1016/j.clinbiomech.2021.105415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 04/19/2021] [Accepted: 05/24/2021] [Indexed: 02/07/2023]
Abstract
Background Proximal junction kyphosis is a common clinical complication of posterior long-segment spinal fusion and vertebral body augmentation method is one of the effective approaches to prevent it. The purpose of this study was to explore the biomechanical effect of proximal junction kyphosis after posterior long-segment thoracolumbar fusion with different vertebral augmentation schemes using finite element analysis. Methods 3D nonlinear finite element models of T1-L5 spine posterior long-segment T8-L5 thoracolumbar fusion combined with T7, T8 and T7&T8 vertebral bone cement augmentation were constructed from human spine CT data and clinical surgical operation scheme to analyze the von Mises stress in the vertebrae, intervertebral discs pressure and pedicle screws system loads under the flexion, extension, lateral bending and axial rotation motion. Findings Compared with thoracolumbar posterior long-segment fusion model, T7 maximum stress in T7, T8 and T7&T8 vertebrae augmentation models were reduced by 8.64%, 7.17%, 8.51%;0.79%, -3.88%,1.67%;4.02%, 5.30%, 4.27% and 3.18%, 3.06%, -6.38% under the flexion, extension, lateral bending and axial rotation motion. T7/T8 intervertebral disc pressure in T7, T8, T7&T8 vertebral augmentation models were 36.71Mpa,29.78Mpa,36.47Mpa;22.25Mpa,18.35Mpa,22.06Mpa;84.27Mpa,68.17Mpa, 83.89Mpa and 52.23Mpa, 38.78Mpa,52.10Mpa under the same condition. The maximum stress 178.2Mpa of pedicle screws is mainly distributed at the root of screw. Interpretation Thoracolumbar posterior long-segment fusion with proximal double-segment vertebral augmentation should be recommended to prevent proximal junction kyphosis than single-segment augmentation. Simulation results can provide theoretical foundations and assist surgeons in selecting the appropriate operation scheme.
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Affiliation(s)
- Gaiping Zhao
- Department of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, China.
| | - Kunneng Wu
- Department of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Dongqing Liu
- Department of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Jian Zhao
- Department of Orthopedics, Western Theater General Hospital, Chengdu, China
| | - Peng Liang
- Department of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Shengqi Hang
- Department of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, China
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Shen H, Chen Y, Liao Z, Liu W. Biomechanical evaluation of anterior lumbar interbody fusion with various fixation options: Finite element analysis of static and vibration conditions. Clin Biomech (Bristol, Avon) 2021; 84:105339. [PMID: 33780788 DOI: 10.1016/j.clinbiomech.2021.105339] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 03/16/2021] [Accepted: 03/23/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND Anterior lumbar interbody fusion combined with supplementary fixation has been widely used to treat lumbar diseases. However, few studies have investigated the influence of fixation options on facet joint force and cage subsidence. The aim of this study was to explore the biomechanical performance of anterior lumbar interbody fusion with various fixation options under both static and vertical vibration loading conditions. METHODS A previously validated finite element model of the intact L1-5 lumbar spine was employed to compare five conditions: (1) Intact; (2) Fusion alone; (3) Fusion combined with anterior lumbar plate; (4) Fusion combined with Coflex-F fixation; (5) Fusion combined with bilateral pedicle screw fixation. The models were analyzed under static and vertical vibration loading conditions respectively. FINDINGS Bilateral pedicle screws provided highest stability at surgical level. Applying supplementary fixation diminished the dynamic responses of lumbar spine. Compared with anterior lumbar plate and Coflex-F device, bilateral pedicle screws decreased the stress responses of the endplates and cage under both static and vibration conditions, while increased the facet joint force at adjacent levels. As for comparison between Coflex-F device and anterior lumbar plate, results showed a similarity in biomechanical performance under static loading, and a slightly higher dynamic response of the latter under vertical vibration. INTERPRETATION The biomechanical performance of lumbar spine was significantly influenced by the variation of fixations under both static and vibration conditions. Bilateral pedicle screws showed advantages in stabilizing surgical segment and relieving cage subsidence, but may increase the facet joint force at adjacent levels.
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Affiliation(s)
- Hangkai Shen
- Department of Mechanical Engineering, Tsinghua University, Beijing 100086, China; Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057, China
| | - Yuru Chen
- Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057, China
| | - Zhenhua Liao
- Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057, China
| | - Weiqiang Liu
- Department of Mechanical Engineering, Tsinghua University, Beijing 100086, China; Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057, China.
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Yin JY, Guo LX. Biomechanical analysis of lumbar spine with interbody fusion surgery and U-shaped lumbar interspinous spacers. Comput Methods Biomech Biomed Engin 2020; 24:1-11. [PMID: 33241697 DOI: 10.1080/10255842.2020.1851368] [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: 08/01/2020] [Revised: 10/11/2020] [Accepted: 11/11/2020] [Indexed: 10/22/2022]
Abstract
Previous research indicates whole-body vibration may lead to low back pain. The aim of this study is assessing the dynamic characteristics of a lumbar spine with Coflex and Coflex-F (commercial implants used as lumbar interspinous spacers) and effect of lumbar interbody fusion surgery. A transient dynamic analysis is performed on three numerical lumbar spine models under the loading condition of a vertical sinusoidal force of ±40 N with a compressive follower preload of 400 N. Also, Coflex-F model with and without interbody fusion surgery is analyzed under the same loading condition. The results show that the maximum value and vibration amplitude of von Mises stress in annulus ground substance (AGS) and intradiscal pressure (IDP) at implanted segment decrease from healthy model to Coflex model, and Coflex-F model. By contrast, for adjacent segments the maximum value of implanted models are larger than that of healthy model. The maximum value of endplates with and without cage are 2.44 MPa and 1.73 MPa (L4 inferior endplate), 1.94 MPa and 1.42 MPa (L5 superior endplate), respectively. The vibration amplitude of Coflex-F model with fusion surgery is smaller than that without fusion surgery. Coflex and Coflex-F not only protect implanted segment but also have a negative effect on adjacent segments. Inserting cage for Coflex-F model can absorb vibration energy at adjacent segments.
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Affiliation(s)
- Jia-Yu Yin
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
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Biomechanical Analysis of Different Lumbar Interspinous Process Devices: A Finite Element Study. World Neurosurg 2019; 127:e1112-e1119. [DOI: 10.1016/j.wneu.2019.04.051] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/03/2019] [Accepted: 04/04/2019] [Indexed: 12/27/2022]
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Fan W, Guo LX. A comparison of the influence of three different lumbar interbody fusion approaches on stress in the pedicle screw fixation system: Finite element static and vibration analyses. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2019; 35:e3162. [PMID: 30294902 DOI: 10.1002/cnm.3162] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 09/13/2018] [Accepted: 10/01/2018] [Indexed: 06/08/2023]
Abstract
This study aimed to examine breakage risk of the bilateral pedicle screw (BPS) fixation system under static and vibration loadings after three different types of lumbar interbody fusion surgery. A previously validated intact L1-sacrum finite element model was modified to simulate anterior, posterior, and transforaminal lumbar interbody fusion (ALIF, PLIF, and TLIF, respectively) with BPS fixation system (consisting of pedicle screws and rigid connecting rods) at L4-L5. As a risk parameter for breakage, the von Mises stresses in the pedicle screws and the rods for the ALIF, PLIF, and TLIF models under static loading (flexion, extension, lateral bending, and axial torsion moments) and vibration loading (sinusoidal vertical load) were calculated and compared. The calculated von Mises stresses were different in the ALIF, PLIF, and TLIF models, but these stresses for all the fusion models were found to be concentrated in neck of the pedicle screw and middle of the rod under both the static and vibration loadings. The results from static analyses showed that the maximum stress in the BPS fixation system was greater in the TLIF model than in the ALIF and PLIF models under all the applied static loadings. The results from transient dynamic analyses also showed that the TLIF generated greater dynamic responses of the stress in the BPS fixation system to the vertical vibration compared with the ALIF and PLIF. It implies that the TLIF procedure might incur a higher risk of breakage for the BPS fixation system than the ALIF and PLIF procedures.
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Affiliation(s)
- Wei Fan
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
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Fan W, Guo LX. Biomechanical comparison of the effects of anterior, posterior and transforaminal lumbar interbody fusion on vibration characteristics of the human lumbar spine. Comput Methods Biomech Biomed Engin 2019; 22:490-498. [DOI: 10.1080/10255842.2019.1566816] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Wei Fan
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
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