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Guo LX, Zhang DX, Zhang M. Destruction mechanism of anterior cervical discectomy and fusion in frontal impact. Med Biol Eng Comput 2024:10.1007/s11517-024-03167-z. [PMID: 39048839 DOI: 10.1007/s11517-024-03167-z] [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: 02/24/2024] [Accepted: 06/22/2024] [Indexed: 07/27/2024]
Abstract
The aim of this study was to quantitatively study the effect of anterior cervical discectomy and fusion (ACDF) on the risk of spinal injury under frontal impact. A head-neck finite element model incorporating active neck muscles and soft tissues was developed and validated. Based on the intact head-neck model, three ACDF models (single-level, two-level and three-level) were used to analyze the frontal impact responses of the head-neck. The results revealed that various surgical approaches led to distinct patterns of vertebral damage under frontal impact. For single-level and three-level ACDFs, vertebral destruction was mainly concentrated at the lower end of the fused segment, while the other vertebrae were not significantly damaged. For two-level ACDF, the lowest vertebra was the first to suffer destruction, followed by severe damage to both the upper and lower vertebrae, while the middle vertebra of the cervical spine exhibited only partial damage around the screws. Fusion surgery for cervical spine injuries predominantly influences the vertebral integrity of the directly fused segments when subjected to frontal impact, while exerting a comparatively lesser impact on the cross-sectional properties of adjacent, non-fused segments.
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Affiliation(s)
- Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, 110819, China.
| | - Dong-Xiang Zhang
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, 110819, China
| | - Ming Zhang
- Res Inst Sports Sci & Technol, Hong Kong Polytechnic University, Hong Kong, 999077, China
- Dept Biomed Engn, Hong Kong Polytechnic University, Hong Kong, 999077, China
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Hu Y, Liu S, Yang R, Wang H. Biomechanical Analysis of a Newly Proposed Surgical Combination (MIS Screw-Rod System for Indirect Decompression+ Interspinous Fusion System for long Term Spinal Stability) in Treatment of Lumbar Degenerative Diseases. World Neurosurg 2024; 184:e809-e820. [PMID: 38364897 DOI: 10.1016/j.wneu.2024.02.061] [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: 02/07/2024] [Accepted: 02/10/2024] [Indexed: 02/18/2024]
Abstract
OBJECTIVE The aim of this study is to analyze the biomechanical stability of a newly proposed surgical combination (minimally invasive surgery of screw-rod system for indirect decompression + interspinous fusion system for long term spinal stability) in treatment of lumbar degenerative diseases. METHODS The three-dimensional (3D) computed tomography (CT) image data of an adult healthy male volunteer were selected. An intact model of L4/5 was further established and validated by using Mimic and 3-matic, 3D slicer, abaqus, Python. Four surgical models were constructed. The biomechanical stability among these surgical modes was compared and analyzed using finite element analysis. RESULTS The maximum von mises on fixation system in surgical models 2 and 3 exhibited comparable values. This finding suggested that the increase in interspinous fusion did not result in a significant elevation in maximum von mises on fixation system. Compared with the third surgical model, the fourth model, which received less average von mises experienced by the screw in contact with both cancellous and cortical bone. The findings indicated that the inclusion of facet joint fusion in surgical procedures might not be necessary to increase the average von Mises stress experienced by the screw in contact with both cancellous and cortical bone. CONCLUSIONS The biomechanical stability of the newly proposed surgical combination (MIS screw-rod for indirect decompression + interspinous fusion for long term spinal stability technique) was not lower than that of the other surgical combination groups, and it might not be necessary to perform facet joint fusion during the surgery.
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Affiliation(s)
- Yunxiang Hu
- School of Graduates, Dalian Medical University, Dalian City, Liaoning Province, China; Department of Orthopedics, Dalian Municipal Central Hospital Affiliated of Dalian Medical University, Dalian City, Liaoning Province, China
| | - Sanmao Liu
- School of Graduates, Dalian Medical University, Dalian City, Liaoning Province, China; Department of Orthopedics, Dalian Municipal Central Hospital Affiliated of Dalian Medical University, Dalian City, Liaoning Province, China
| | - Rui Yang
- School of Graduates, Dalian Medical University, Dalian City, Liaoning Province, China; Department of Orthopedics, Dalian Municipal Central Hospital Affiliated of Dalian Medical University, Dalian City, Liaoning Province, China
| | - Hong Wang
- Department of Orthopedics, Dalian Municipal Central Hospital Affiliated of Dalian Medical University, Dalian City, Liaoning Province, China.
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Ye S, Ye J, Hou Z, You X, Shen S, Zhang J, Yu L, Gu Y, Wang W, Zhao L. Biomechanical study of anterior transpedicular root screw intervertebral fusion system of lower cervical spine: a finite element analysis. Front Bioeng Biotechnol 2024; 12:1352996. [PMID: 38357708 PMCID: PMC10865374 DOI: 10.3389/fbioe.2024.1352996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 01/18/2024] [Indexed: 02/16/2024] Open
Abstract
Background: The cervical anterior transpedicular screw (ATPS) fixation technology can provide adequate stability for cervical three-column injuries. However, its high risk of screw insertion and technical complexity have restricted its widespread clinical application. As an improvement over the ATPS technology, the cervical anterior transpedicular root screw (ATPRS) technology has been introduced to reduce the risk associated with screw insertion. This study aims to use finite element analysis (FEA) to investigate the biomechanical characteristics of a cervical spine model after using the novel ATPRS intervertebral fusion system, providing insights into its application and potential refinement. Methods: A finite element (FE) model of the C3-C7 lower cervical spine was established and validated. After two-level (C4-C6) anterior cervical discectomy and fusion (ACDF) surgery, FE models were constructed for the anterior cervical locked-plate (ACLP) internal fixation, the ATPS internal fixation, and the novel ATPRS intervertebral fusion system. These models were subjected to 75N axial force and 1.0 Nm to induce various movements. The range of motion (ROM) of the surgical segments (C4-C6), maximum stress on the internal fixation systems, and maximum stress on the adjacent intervertebral discs were tested and recorded. Results: All three internal fixation methods effectively reduced the ROM of the surgical segments. The ATPRS model demonstrated the smallest ROM during flexion, extension, and rotation, but a slightly larger ROM during lateral bending. Additionally, the maximum bone-screw interface stresses for the ATPRS model during flexion, extension, lateral bending, and axial rotation were 32.69, 64.24, 44.07, 35.89 MPa, which were lower than those of the ACLP and ATPS models. Similarly, the maximum stresses on the adjacent intervertebral discs in the ATPRS model during flexion, extension, lateral bending, and axial rotation consistently remained lower than those in the ACLP and ATPS models. However, the maximum stresses on the cage and the upper endplate of the ATPRS model were generally higher. Conclusion: Although the novel ATPRS intervertebral fusion system generally had greater endplate stress than ACLP and ATPS, it can better stabilize cervical three-column injuries and might reduce the occurrence of adjacent segment degeneration (ASD). Furthermore, further studies and improvements are necessary for the ATPRS intervertebral fusion system.
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Affiliation(s)
- Senqi Ye
- Department of Spinal Surgery, Yuyao People’s Hospital, Yuyao, China
| | - Jiachun Ye
- The Affiliated Lihuili Hospital, Ningbo University, Ningbo, China
| | - Zhipeng Hou
- Health Science Center, Ningbo University, Ningbo, China
| | - Xinmao You
- Department of Spinal Surgery, Yuyao People’s Hospital, Yuyao, China
| | - Shufeng Shen
- Department of Spinal Surgery, Yuyao People’s Hospital, Yuyao, China
| | - Jihui Zhang
- Department of Spinal Surgery, Ningbo No 6.Hospital of Ningbo University, Ningbo, China
| | - Liang Yu
- Department of Spinal Surgery, Ningbo No 6.Hospital of Ningbo University, Ningbo, China
| | - Yongjie Gu
- Department of Spinal Surgery, Ningbo No 6.Hospital of Ningbo University, Ningbo, China
| | - Wei Wang
- Urumqi DW Innovation Infotech Co., Ltd., Urumqi, Xinjiang, China
| | - Liujun Zhao
- Department of Spinal Surgery, Ningbo No 6.Hospital of Ningbo University, Ningbo, China
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Sun Z, Sun Y, Mi C. Comprehensive modeling of annulus fibrosus: From biphasic refined characterization to damage accumulation under viscous loading. Acta Biomater 2024; 174:228-244. [PMID: 38070844 DOI: 10.1016/j.actbio.2023.12.007] [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: 09/06/2023] [Revised: 11/26/2023] [Accepted: 12/05/2023] [Indexed: 12/17/2023]
Abstract
The annulus fibrosus (AF), a permeable, hydrated, and fiber-reinforced soft tissue, exhibits complex responses influenced by fluid pressure, osmotic pressure, and structural mechanics. Existing models struggle to comprehensively represent these intricate interactions and the heterogeneous solid responses within the AF. Additionally, the mechanisms driving differential damage accumulation between non-degenerative and degenerative intervertebral discs remain poorly understood. In this study, we introduce a biphasic-swelling damage model for the AF. We conceptually develop and rigorously validate this model through tissue-level tests employing various loading modes, consistently aligning model predictions with experimental data. Leveraging parametric geometric algorithms and custom Python scripts, we construct models simulating both non-degenerative and degenerative discs. Following calibration, we subject these models to viscous loading protocols. Our findings reveal the posterior AF's susceptibility to damage, contingent upon loading rate and water content. We elucidate the underlying mechanisms by examining the temporal evolution of fluid pressure, osmotic pressure, and the regionally dependent fiber network. This research presents a highly accurate model of the AF, providing valuable insights into disc damage. Future research endeavors should expand this model to incorporate ionic transport and diffusion, enabling a more profound exploration of intervertebral disc mechanobiology. This comprehensive model contributes to a better understanding of AF behavior and may inform therapeutic strategies for disc-related pathologies. STATEMENT OF SIGNIFICANCE: This research presents a comprehensive model of the annulus fibrosus (AF), a crucial component of the intervertebral disc that provides structural support and resists deformation. The study introduces a biphasic-swelling damage model for the AF and validates it through tissue-level tests. The model accounts for fluid pressure, osmotic pressure, and matrix mechanics, providing a more accurate representation of the AF's behavior. The study also investigates the differential damage accumulation between non-degenerative and degenerative discs, shedding light on the mechanisms driving disc degeneration. The findings have significant implications for medical treatments and interventions, as they highlight the posterior AF's susceptibility to damage. This research is of great interest to readers interested in biomechanics, tissue engineering, and medical treatments for disc degeneration.
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Affiliation(s)
- Zhongwei Sun
- Jiangsu Key Laboratory of Engineering Mechanics, School of Civil Engineering, Southeast University, Nanjing, Jiangsu 210096, China
| | - Yueli Sun
- Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, Shanghai 200032, China
| | - Changwen Mi
- Jiangsu Key Laboratory of Engineering Mechanics, School of Civil Engineering, Southeast University, Nanjing, Jiangsu 210096, China.
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Nikpasand M, Abbott RE, Kage CC, Singh S, Winkelstein BA, Barocas VH, Ellingson AM. Cervical facet capsular ligament mechanics: Estimations based on subject-specific anatomy and kinematics. JOR Spine 2023; 6:e1269. [PMID: 37780821 PMCID: PMC10540825 DOI: 10.1002/jsp2.1269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/30/2023] [Accepted: 06/02/2023] [Indexed: 10/03/2023] Open
Abstract
Background To understand the facet capsular ligament's (FCL) role in cervical spine mechanics, the interactions between the FCL and other spinal components must be examined. One approach is to develop a subject-specific finite element (FE) model of the lower cervical spine, simulating the motion segments and their components' behaviors under physiological loading conditions. This approach can be particularly attractive when a patient's anatomical and kinematic data are available. Methods We developed and demonstrated methodology to create 3D subject-specific models of the lower cervical spine, with a focus on facet capsular ligament biomechanics. Displacement-controlled boundary conditions were applied to the vertebrae using kinematics extracted from biplane videoradiography during planar head motions, including axial rotation, lateral bending, and flexion-extension. The FCL geometries were generated by fitting a surface over the estimated ligament-bone attachment regions. The fiber structure and material characteristics of the ligament tissue were extracted from available human cervical FCL data. The method was demonstrated by application to the cervical geometry and kinematics of a healthy 23-year-old female subject. Results FCL strain within the resulting subject-specific model were subsequently compared to models with generic: (1) geometry, (2) kinematics, and (3) material properties to assess the effect of model specificity. Asymmetry in both the kinematics and the anatomy led to asymmetry in strain fields, highlighting the importance of patient-specific models. We also found that the calculated strain field was largely independent of constitutive model and driven by vertebrae morphology and motion, but the stress field showed more constitutive-equation-dependence, as would be expected given the highly constrained motion of cervical FCLs. Conclusions The current study provides a methodology to create a subject-specific model of the cervical spine that can be used to investigate various clinical questions by coupling experimental kinematics with multiscale computational models.
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Affiliation(s)
- Maryam Nikpasand
- Department of Mechanical EngineeringUniversity of Minnesota—Twin CitiesMinneapolisMinnesotaUSA
| | - Rebecca E. Abbott
- Department of Rehabilitation MedicineUniversity of Minnesota—Twin CitiesMinneapolisMinnesotaUSA
| | - Craig C. Kage
- Department of Rehabilitation MedicineUniversity of Minnesota—Twin CitiesMinneapolisMinnesotaUSA
| | - Sagar Singh
- Department of BioengineeringUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Beth A. Winkelstein
- Department of BioengineeringUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Victor H. Barocas
- Department of Mechanical EngineeringUniversity of Minnesota—Twin CitiesMinneapolisMinnesotaUSA
- Department of Biomedical EngineeringUniversity of Minnesota—Twin CitiesMinneapolisMinnesotaUSA
| | - Arin M. Ellingson
- Department of Rehabilitation MedicineUniversity of Minnesota—Twin CitiesMinneapolisMinnesotaUSA
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Yang C, Wang F, Huang X, Zhang H, Zhang M, Gao J, Shi S, Wang F, Yang F, Yu X. Finite element analysis of biomechanical effects of mineralized collagen modified bone cement on adjacent vertebral body after vertebroplasty. Front Bioeng Biotechnol 2023; 11:1166840. [PMID: 37485322 PMCID: PMC10358328 DOI: 10.3389/fbioe.2023.1166840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 06/29/2023] [Indexed: 07/25/2023] Open
Abstract
Objective: To investigate whether mineralized collagen modified polymethyl methacrylate (MC-PMMA) bone cement impacts the implanted vertebral body and adjacent segments and the feasibility of biomechanical properties compared with common bone cement in the treatment of osteoporotic vertebral compression fractures (OVCF). Methods: A healthy volunteer was selected to perform a three-dimensional reconstruction of the T11-L1 vertebral body to establish the corresponding finite element model of the spine, and the changes in the stress distribution of different types of cement were biomechanically analyzed in groups by applying quantitative loads. Results: The stress distribution of the T11-L1 vertebral body was similar between the two bone types of cement under various stress conditions. Conclusion: Mineralized collagen modified bone cement had the advantages of promoting bone regeneration, good biocompatibility, good transformability, and coupling, and had support strength not inferior to common PMMA bone cement, indicating it has good development prospects and potential.
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Affiliation(s)
- Cunheng Yang
- Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Fumin Wang
- Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Xingxing Huang
- Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Hao Zhang
- Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Meng Zhang
- Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Junxiao Gao
- Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Shengbo Shi
- Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Fuyang Wang
- Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Fangjun Yang
- Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Xiaobing Yu
- Affiliated Zhongshan Hospital of Dalian University, Dalian, China
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Li J, Cao S, Guo D, Lu T, Zang Q. Biomechanical properties of different anterior and posterior techniques for atlantoaxial fixation: a finite element analysis. J Orthop Surg Res 2023; 18:456. [PMID: 37365580 DOI: 10.1186/s13018-023-03905-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 06/03/2023] [Indexed: 06/28/2023] Open
Abstract
BACKGROUND Many techniques for atlantoaxial fixation have been developed. However, the biomechanical differences among various atlantoaxial fixation methods remain unclear. This study aimed to evaluate the biomechanical influence of anterior and posterior atlantoaxial fixation techniques on fixed and nonfixed segments. METHODS An occiput-C7 cervical finite element model was used to construct 6 surgical models including a Harms plate, a transoral atlantoaxial reduction plate (TARP), an anterior transarticular screw (ATS), a Magerl screw, a posterior screw-plate, and a screw-rod system. Range of motion (ROM), facet joint force (FJF), disc stress, screw stress, and bone-screw interface stress were calculated. RESULTS The C1/2 ROMs were relatively small in the ATS and Magerl screw models under all loading directions except for extension (0.1°-1.0°). The posterior screw-plate system and screw-rod system generated greater stresses on the screws (77.6-1018.1 MPa) and bone-screw interfaces (58.3-499.0 MPa). The Harms plate and TARP models had relatively small ROMs (3.2°-17.6°), disc stress (1.3-7.6 MPa), and FJF (3.3-106.8 N) at the nonfixed segments. Changes in disc stress and FJF of the cervical segments were not consistent with changes in ROM. CONCLUSIONS ATS and Magerl screws may provide good atlantoaxial stability. The posterior screw-rod system and screw-plate system may have higher risks of screw loosening and breakage. The Harms plate and TARP model may more effectively relieve nonfixed segment degeneration than other techniques. The C0/1 or C2/3 segment may not be more susceptible to degeneration than other nonfixed segments after C1/2 fixation.
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Affiliation(s)
- Jie Li
- Department of Orthopedics, The Second Affiliated Hospital of Xi'an Jiaotong University, 157Th West Fifth Road, Xi'an, 710004, Shaanxi Province, China
| | - Shuai Cao
- Department of Orthopedics, Civil Aviation General Hospital, No. 1, Gaojing Stress, Chaoyang District, Beijing, 100123, China
| | - Dong Guo
- Department of Orthopedics, The Second Affiliated Hospital of Xi'an Jiaotong University, 157Th West Fifth Road, Xi'an, 710004, Shaanxi Province, China
| | - Teng Lu
- Department of Orthopedics, The Second Affiliated Hospital of Xi'an Jiaotong University, 157Th West Fifth Road, Xi'an, 710004, Shaanxi Province, China.
| | - Quanjin Zang
- Department of Orthopedics, The Second Affiliated Hospital of Xi'an Jiaotong University, 157Th West Fifth Road, Xi'an, 710004, Shaanxi Province, China.
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Sun X, Zhang Q, Cao L, Wang J, Huang J, Liu Y, Zhang Y, Song Z, Tang W, Chen Y, Sun S, Lu S. Biomechanical effects of hybrid constructions in the treatment of noncontinuous cervical spondylopathy: a finite element analysis. J Orthop Surg Res 2023; 18:57. [PMID: 36658557 PMCID: PMC9854215 DOI: 10.1186/s13018-023-03537-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 01/12/2023] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Hybrid construction (HC) may be an ideal surgical strategy than noncontinuous total disc replacement (TDR) and noncontinuous anterior cervical discectomy and fusion (ACDF) in the treatment of noncontinuous cervical spondylopathy. However, there is still no consensus on the segmental selection for ACDF or TDR in HC. The study aims to analyse the effects of different segment selection of TDR and ACDF on cervical biomechanical characteristics after HC surgery. METHODS Twelve FEMs of C2-C7 were constructed based on CT images of 12 mild cervical spondylopathy volunteers. Two kinds of HC were introduced in our study: Fusion-arthroplasty group (Group 1), upper-level (C3/4) ACDF, and lower-level TDR (C5/6); Arthroplasty-fusion group (Group 2), upper-level (C3/4) TDR and lower-level ACDF (C5/6). The follow-load technique was simulated by applying an axial initial load of 73.6 N through the motion centre of FEM. A bending moment of 1.0 Nm was applied to the centre of C2 in all FEMs. Statistical analysis was carried out by SPSS 26.0. The significance threshold was 5% (P < 0.05). RESULTS In the comparison of ROMs between Group 1 and Group 2, the ROM in extension (P = 0.016), and lateral bending (P = 0.038) of C4/5 were significantly higher in Group 1 group. The average intervertebral disc pressures at C2/3 in all directions were significantly higher in Group 1 than those in Group 2 (P < 0.005). The average contact forces in facet joints of C2/3 (P = 0.007) were significantly more than that in Group 2; however, the average contact forces in facet joints of C6/7 (P < 0.001) in Group 1 group were significantly less than that in Group 2. CONCLUSIONS Arthroplasty-fusion is preferred for intervertebral disc degeneration in adjacent upper segments. Fusion-arthroplasty is preferred for patients with lower intervertebral disc degeneration or lower posterior column degeneration. TRIAL REGISTRATION This research was registered in Chinese Clinical Trial Registry (ChiCTR1900020513).
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Affiliation(s)
- Xiangyao Sun
- grid.413259.80000 0004 0632 3337Department of Orthopaedics, Xuanwu Hospital Capital Medical University, Beijing, 100053 China ,National Clinical Research Center for Geriatric Diseases, Beijing, 100053 China ,Beijing Glitzern Technology Co., Ltd, Beijing, 100077 China
| | - Qingming Zhang
- grid.413259.80000 0004 0632 3337Department of Orthopaedics, Xuanwu Hospital Capital Medical University, Beijing, 100053 China ,National Clinical Research Center for Geriatric Diseases, Beijing, 100053 China
| | - Li Cao
- grid.413259.80000 0004 0632 3337Department of Orthopaedics, Xuanwu Hospital Capital Medical University, Beijing, 100053 China ,National Clinical Research Center for Geriatric Diseases, Beijing, 100053 China
| | - Juyong Wang
- grid.413259.80000 0004 0632 3337Department of Orthopaedics, Xuanwu Hospital Capital Medical University, Beijing, 100053 China ,National Clinical Research Center for Geriatric Diseases, Beijing, 100053 China
| | - Jiang Huang
- grid.413259.80000 0004 0632 3337Department of Orthopaedics, Xuanwu Hospital Capital Medical University, Beijing, 100053 China ,National Clinical Research Center for Geriatric Diseases, Beijing, 100053 China
| | - Yuqi Liu
- grid.413259.80000 0004 0632 3337Department of Emergency, Xuanwu Hospital, Capital Medical University, Beijing, 100053 China
| | - Yang Zhang
- grid.414252.40000 0004 1761 8894Department of Orthopaedics, The Seventh Medical Center of PLA General Hospital, Beijing, 100191 China
| | - Zelong Song
- grid.216938.70000 0000 9878 7032Nankai University School of Medicine, Nankai University, Tianjin, 300071 China ,grid.414252.40000 0004 1761 8894Department of Orthopaedics, The PLA General Hospital, Beijing, 100000 China
| | - Wei Tang
- Beijing Glitzern Technology Co., Ltd, Beijing, 100077 China
| | - Yunqiang Chen
- Beijing Glitzern Technology Co., Ltd, Beijing, 100077 China
| | - Siyuan Sun
- grid.169077.e0000 0004 1937 2197Department of Interdisciplinary, Life Science, Purdue University, West Lafayette, IN 47907 USA
| | - Shibao Lu
- grid.413259.80000 0004 0632 3337Department of Orthopaedics, Xuanwu Hospital Capital Medical University, Beijing, 100053 China ,National Clinical Research Center for Geriatric Diseases, Beijing, 100053 China
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Hadagali P, Cronin D. Enhancing the Biofidelity of an Upper Cervical Spine Finite Element Model within the Physiologic Range of Motion and Its Effect On the Full Ligamentous Neck Model Response. J Biomech Eng 2022; 145:1143325. [PMID: 35864785 DOI: 10.1115/1.4055037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Indexed: 11/08/2022]
Abstract
Contemporary finite element neck models are developed in a neutral posture; however, evaluation of injury risk for out-of-position impacts requires neck model repositioning to non-neutral postures, with much of the motion occurring in the upper cervical spine (UCS). Current neck models demonstrate a limitation in predicting the intervertebral motions within the UCS within the range of motion (ROM), while recent studies have highlighted the importance of including the tissue strains resulting from repositioning FE neck models to predict injury risk. In the current study, the ligamentous cervical spine from a contemporary neck model (GHBMC M50 v4.5) was evaluated in flexion, extension and axial rotation by applying moments from 0 to 1.5 Nm in 0.5 Nm increments, as reported in experimental studies and corresponding to the physiologic loading of the UCS. Enhancements to the UCS model were identified, including the C0-C1 joint-space and alar ligament orientation. Following geometric enhancements, an analysis was undertaken to determine the UCS ligament laxities, using a sensitivity study followed by an optimization study. The ligament laxities were optimized to UCS-level experimental data from the literature. The mean percent difference between UCS model response and experimental data improved from 55% to 23% with enhancements. The enhanced UCS model was integrated with a ligamentous cervical spine (LS) model and assessed with independent experimental data. The mean percent difference between the LS model and the experimental data improved from 46% to 35% with the integration of the enhanced UCS model.
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Affiliation(s)
- Prasannaah Hadagali
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave. West, Waterloo, Ontario, Canada, N2L 3G1
| | - Duane Cronin
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave. West, Waterloo, Ontario, Canada, N2L 3G1
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Liang W, Han B, Hai Y, Yang J, Yin P. Biomechanical Analysis of the Reasonable Cervical Range of Motion to Prevent Non-Fusion Segmental Degeneration After Single-Level ACDF. Front Bioeng Biotechnol 2022; 10:918032. [PMID: 35782514 PMCID: PMC9243332 DOI: 10.3389/fbioe.2022.918032] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 05/05/2022] [Indexed: 11/13/2022] Open
Abstract
The compensatory increase in intervertebral range of motion (ROM) after cervical fusion can increase facet joint force (FJF) and intradiscal pressure (IDP) in non-fusion segments. Guiding the post-ACDF patient cervical exercise within a specific ROM (defined as reasonable ROM) to offset the increase in FJF and IDP may help prevent segmental degeneration. This study aimed to determine the reasonable total C0–C7 ROM without an increase in FJF and IDP in non-fusion segments after anterior cervical discectomy and fusion (ACDF). A three-dimensional intact finite element model of C0–C7 generated healthy cervical conditions. This was modified to the ACDF model by simulating the actual surgery at C5–C6. A 1.0 Nm moment and 73.6 N follower load were applied to the intact model to determine the ROMs. A displacement load was applied to the ACDF model under the same follower load, resulting in a total C0–C7 ROM similar to that of the intact model. The reasonable ROMs in the ACDF model were calculated using the fitting function. The results indicated that the intervertebral ROM of all non-fusion levels was increased in the ACDF model in all motion directions. The compensatory increase in ROM in adjacent segments (C4/5 and C6/7) was more significant than that in non-adjacent segments, except for C3/4 during lateral bending. The intervertebral FJF and IDP of C0–C7 increased with increasing ROM. The reasonable ROMs in the ACDF model were 42.4°, 52.6°, 28.4°, and 42.25° in flexion, extension, lateral bending, and axial rotation, respectively, with a decreased ROM of 4.4–7.2%. The postoperative increase in FJF and IDP in non-fusion segments can be canceled out by reducing the intervertebral ROM within reasonable ROMs. This study provided a new method to estimate the reasonable ROMs after ACDF from a biomechanical perspective, and further in vitro and clinical studies are needed to confirm this.
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Affiliation(s)
| | | | - Yong Hai
- *Correspondence: Yong Hai, ; Peng Yin,
| | | | - Peng Yin
- *Correspondence: Yong Hai, ; Peng Yin,
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Ansaripour H, Ferguson S, Flohr M. In-vitro Biomechanics of the Cervical Spine: a Systematic Review. J Biomech Eng 2022; 144:1140519. [PMID: 35482019 DOI: 10.1115/1.4054439] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Indexed: 11/08/2022]
Abstract
In-vitro testing has been conducted to provide a comprehensive understanding of the biomechanics of the cervical spine. This has allowed a characterization of the stability of the spine as influenced by the intrinsic properties of its tissue constituents and the severity of degeneration or injury. This also enables the pre-clinical estimation of spinal implant functionality and the success of operative procedures. The purpose of this review paper was to compile methodologies and results from various studies addressing spinal kinematics in pre- and post-operative conditions so that they could be compared. The reviewed literature was evaluated to provide suggestions for a better approach for future studies, to reduce the uncertainties and facilitate comparisons among various results. The overview is presented in a way to inform various disciplines, such as experimental testing, design development, and clinical treatment. The biomechanical characteristics of the cervical spine, mainly the segmental range of motion (ROM), intradiscal pressure (IDP), and facet joint load (FJL), have been assessed by testing functional spinal units (FSUs). The relative effects of pathologies including disc degeneration, muscle dysfunction, and ligamentous transection have been studied by imposing on the specimen complex load scenarios imitating physiological conditions. The biomechanical response is strongly influenced by specimen type, test condition, and the different types of implants utilized in the different experimental groups.
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Affiliation(s)
- Hossein Ansaripour
- CeramTec GmbH, Plochingen, Germany; Institute for Biomechanics, D-HEST, ETH, Zurich, Switzerland, CeramTec GmbH, CeramTec-Platz 1-9, 73207 Plochingen, Germany
| | - Stephen Ferguson
- Institute for Biomechanics, D-HEST, ETH, Zurich, Switzerland, Hönggerbergring 64, HPP O-22, 8093 Zurich, Switzerland
| | - Markus Flohr
- CeramTec GmbH, Plochingen, Germany, CeramTec GmbH, CeramTec-Platz 1-9, 73207 Plochingen, Germany
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Sun Z, Lu T, Li J, Liu J, Hu Y, Mi C. A finite element study on the effects of follower load on the continuous biomechanical responses of subaxial cervical spine. Comput Biol Med 2022; 145:105475. [PMID: 35381450 DOI: 10.1016/j.compbiomed.2022.105475] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/10/2022] [Accepted: 03/29/2022] [Indexed: 11/28/2022]
Abstract
In spine biomechanics, follower loads are used to mimic the in vivo muscle forces acting on a human spine. However, the effects of the follower load on the continuous biomechanical responses of the subaxial cervical spines (C2-T1) have not been systematically clarified. This study aims at investigating the follower load effects on the continuous biomechanical responses of C2-T1. A nonlinear finite element model is reconstructed and validated for C2-T1. Six levels follower loads are considered along the follower load path that is optimized through a novel range of motion-based method. A moment up to 2 Nm is subsequently superimposed to produce motions in three anatomical planes. The continuous biomechanical responses, including the range of motion, facet joint force, intradiscal pressure and flexibility are evaluated for each motion segment. In the sagittal plane, the change of the overall range of motion arising from the follower loads is less than 6%. In the other two anatomical planes, both the magnitude and shape of the rotation-moment curves change with follower loads. At the neutral position, over 50% decrease in flexibility occurs as the follower load increases from zero to 250 N. In all three anatomical planes, over 50% and 30% decreases in flexibility occur in the first 0.5 Nm for small (≤100 N) and large (≥150 N) follower loads, respectively. Moreover, follower loads tend to increase both the facet joint forces and the intradiscal pressures. The shape of the intradiscal pressure-moment curves changes from nonlinear to roughly linear with increased follower load, especially in the coronal and transverse planes. The results obtained in this work provide a comprehensive understanding on the effects of follower load on the continuous biomechanical responses of the C2-T1.
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Affiliation(s)
- Zhongwei Sun
- Jiangsu Key Laboratory of Engineering Mechanics, School of Civil Engineering, Southeast University, 2 Sipailou Street, Nanjing, 210096, Jiangsu, China
| | - Teng Lu
- Department of Orthopedics, Second Affiliated Hospital of Xi'an Jiaotong University, 30 Huangcheng West Road, Xi'an, 710004, Shaanxi, China
| | - Jialiang Li
- Department of Orthopedics, Second Affiliated Hospital of Xi'an Jiaotong University, 30 Huangcheng West Road, Xi'an, 710004, Shaanxi, China
| | - Jiantao Liu
- Department of Orthopedics, First Affiliated Hospital of Xi'an Jiaotong University, 277 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Yuanbin Hu
- Department of Orthopedics, Zhongda Hospital, Southeast University, 2 Sipailou Street, Nanjing, 210096, Jiangsu, China.
| | - Changwen Mi
- Jiangsu Key Laboratory of Engineering Mechanics, School of Civil Engineering, Southeast University, 2 Sipailou Street, Nanjing, 210096, Jiangsu, China.
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Finley SM, Astin JH, Joyce E, Dailey AT, Brockmeyer DL, Ellis BJ. FEBio finite element model of a pediatric cervical spine. J Neurosurg Pediatr 2022; 29:218-224. [PMID: 34678779 DOI: 10.3171/2021.7.peds21276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 07/28/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The underlying biomechanical differences between the pediatric and adult cervical spine are incompletely understood. Computational spine modeling can address that knowledge gap. Using a computational method known as finite element modeling, the authors describe the creation and evaluation of a complete pediatric cervical spine model. METHODS Using a thin-slice CT scan of the cervical spine from a 5-year-old boy, a 3D model was created for finite element analysis. The material properties and boundary and loading conditions were created and model analysis performed using open-source software. Because the precise material properties of the pediatric cervical spine are not known, a published parametric approach of scaling adult properties by 50%, 25%, and 10% was used. Each scaled finite element model (FEM) underwent two types of simulations for pediatric cadaver testing (axial tension and cardinal ranges of motion [ROMs]) to assess axial stiffness, ROM, and facet joint force (FJF). The authors evaluated the axial stiffness and flexion-extension ROM predicted by the model using previously published experimental measurements obtained from pediatric cadaveric tissues. RESULTS In the axial tension simulation, the model with 50% adult ligamentous and annulus material properties predicted an axial stiffness of 49 N/mm, which corresponded with previously published data from similarly aged cadavers (46.1 ± 9.6 N/mm). In the flexion-extension simulation, the same 50% model predicted an ROM that was within the range of the similarly aged cohort of cadavers. The subaxial FJFs predicted by the model in extension, lateral bending, and axial rotation were in the range of 1-4 N and, as expected, tended to increase as the ligament and disc material properties decreased. CONCLUSIONS A pediatric cervical spine FEM was created that accurately predicts axial tension and flexion-extension ROM when ligamentous and annulus material properties are reduced to 50% of published adult properties. This model shows promise for use in surgical simulation procedures and as a normal comparison for disease-specific FEMs.
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Affiliation(s)
- Sean M Finley
- 1Department of Biomedical Engineering and Scientific Computing and Imaging Institute, and
| | - J Harley Astin
- 1Department of Biomedical Engineering and Scientific Computing and Imaging Institute, and
| | - Evan Joyce
- 2Department of Neurosurgery, Division of Pediatric Neurosurgery, University of Utah, Salt Lake City, Utah
| | - Andrew T Dailey
- 2Department of Neurosurgery, Division of Pediatric Neurosurgery, University of Utah, Salt Lake City, Utah
| | - Douglas L Brockmeyer
- 2Department of Neurosurgery, Division of Pediatric Neurosurgery, University of Utah, Salt Lake City, Utah
| | - Benjamin J Ellis
- 1Department of Biomedical Engineering and Scientific Computing and Imaging Institute, and
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