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Wang DH, Wu DN, Xin DQ, Shi Q, Wang WX, Xing WH, Yang HL. Biomechanical analysis of adjacent segments after correction surgery for adult idiopathic scoliosis: a finite element analysis. Sci Rep 2024; 14:13181. [PMID: 38849364 PMCID: PMC11161469 DOI: 10.1038/s41598-024-63113-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 05/24/2024] [Indexed: 06/09/2024] Open
Abstract
The biomechanical aspects of adjacent segment degeneration after Adult Idiopathic Scoliosis (AdIS) corrective surgery involving postoperative changes in motion and stress of adjacent segments have yet to be investigated. The objective of this study was to evaluate the biomechanical effects of corrective surgery on adjacent segments in adult idiopathic scoliosis by finite element analysis. Based on computed tomography data of the consecutive spine from T1-S1 of a 28-year-old male patient with adult idiopathic scoliosis, a three-dimensional finite element model was established to simulate the biomechanics. Two posterior long-segment fixation and fusion operations were designed: Strategy A, pedicle screws implanted in all segments of both sides, and Strategy B, alternate screws instrumentation on both sides. The range of motion (ROM), Maximum von Mises stress value of intervertebral disc (IVD), and Maximum von Mises stress of the facet joint (FJ) at the fixation adjacent segment were calculated and compared with data of the preoperative AdIS model. Corrective surgery decreased the IVD on the adjacent segments, increased the FJ on the adjacent segments, and decreased the ROM of the adjacent segments. A greater decrease of Maximum von Mises stress was observed on the distal adjacent segment compared with the proximal adjacent segment. The decrease of Maximum von Mises stress and increment of Maximum von Mises stress on adjacent FJ in strategy B was greater than that in strategy A. Under the six operation modes, the change of the Maximum von Mises stress on the adjacent IVD and FJ was significant. The decrease in ROM in the proximal adjacent segment was greater than that of the distal adjacent segment, and the decrease of ROM in strategy A was greater than that in strategy B. This study clarified the biomechanical characteristics of adjacent segments after AdIS corrective surgery, and further biomechanical analysis of two different posterior pedicle screw placement schemes by finite element method. Our study provides a theoretical basis for the pathogenesis, prevention, and treatment of adjacent segment degeneration after corrective surgery for AdIS.
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Affiliation(s)
- Dong-Hai Wang
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute of Soochow University, 188 Shizi Road, Suzhou, 215006, Jiangsu, People's Republic of China
- Department of Orthopedics, The Second Affiliated Hospital of Inner Mongolia Medical University, Orthopedic Institute of Inner Mongolia Autonomous Region, 59 Horqin South Road, Hohhot, 010090, Inner Mongolia, People's Republic of China
| | - Dan-Ni Wu
- School of Kinesiology, Shanghai University of Sport, Research Building 412, 200 Hengren Road, Shanghai, 200438, People's Republic of China
- Department of Orthopedics, The Second Affiliated Hospital of Inner Mongolia Medical University, Orthopedic Institute of Inner Mongolia Autonomous Region, 59 Horqin South Road, Hohhot, 010090, Inner Mongolia, People's Republic of China
| | - Da-Qi Xin
- Department of Orthopedics, The Second Affiliated Hospital of Inner Mongolia Medical University, Orthopedic Institute of Inner Mongolia Autonomous Region, 59 Horqin South Road, Hohhot, 010090, Inner Mongolia, People's Republic of China
| | - Qin Shi
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute of Soochow University, 188 Shizi Road, Suzhou, 215006, Jiangsu, People's Republic of China
| | - Wen-Xuan Wang
- Department of Orthopedics, The Second Affiliated Hospital of Inner Mongolia Medical University, Orthopedic Institute of Inner Mongolia Autonomous Region, 59 Horqin South Road, Hohhot, 010090, Inner Mongolia, People's Republic of China
- Department of Orthopedics, The Children's Hospital of Soochow University, 92 Zhongnan Street, Suzhou, 215025, Jiangsu, People's Republic of China
| | - Wen-Hua Xing
- Department of Orthopedics, The Second Affiliated Hospital of Inner Mongolia Medical University, Orthopedic Institute of Inner Mongolia Autonomous Region, 59 Horqin South Road, Hohhot, 010090, Inner Mongolia, People's Republic of China.
| | - Hui-Lin Yang
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute of Soochow University, 188 Shizi Road, Suzhou, 215006, Jiangsu, People's Republic of China.
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Guo LX, Liu J. Topology optimization and dynamic characteristic evaluation of W-shaped interspinous process device. Comput Methods Biomech Biomed Engin 2023; 26:1610-1619. [PMID: 36200492 DOI: 10.1080/10255842.2022.2129968] [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: 12/10/2021] [Revised: 09/21/2022] [Accepted: 09/25/2022] [Indexed: 11/03/2022]
Abstract
For reducing the adjacent segment degeneration of the lumbar spine, the interspinous process device as a kind of flexible non-fusion device was designed to overcome the deficiencies associated with rigid fusion devices. However, it was not clear how the interspinous process device influenced the human spine system, especially the lumbar spine under a vibration environment. This study was designed to evaluate the effect of StenoFix under the vibration condition and also to optimize the structure of the device to obtain better biomechanical performance. A finite element model of the intact lumbar spine was developed and validated. The surgical finite element model was constructed by implanting the interspinous process device StenoFix. Using topology optimization, a new device StenoFix-new was redesigned. The results showed that the interspinous process device decreased vibration amplitudes of annulus stress and intradiscal pressure under vibration at the surgical level. The redesigned StenoFix-new with the smaller stiffness exhibited a better dynamic flexibility performance than StenoFix. In addition, the range of motions of StenoFix-new was closer to the intact model than StenoFix at the surgical level. These results might encourage the designers to give more consideration to the dynamic characteristics of the human spine on the premise of ensuring the safety and strength of implanted devices.
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Affiliation(s)
- Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Juan Liu
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
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Fan W, Zhang C, Wang QD, Guo LX, Zhang M. The effects of topping-off instrumentation on biomechanics of sacroiliac joint after lumbosacral fusion. Comput Biol Med 2023; 164:107357. [PMID: 37586205 DOI: 10.1016/j.compbiomed.2023.107357] [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: 04/29/2023] [Revised: 08/02/2023] [Accepted: 08/12/2023] [Indexed: 08/18/2023]
Abstract
BACKGROUND Lumbar/lumbosacral fusion supplemented with topping-off devices has been proposed with the aim of avoiding adjacent segment degeneration proximal to the fusion construct. However, it remains unclear how the biomechanics of the sacroiliac joint (SIJ) are altered after topping-off surgery. The objective of this study was to investigate the biomechanical effects of topping-off instrumentation on SIJ after lumbosacral fusion. METHODS The validated finite element model of an intact lumbar spine-pelvis segment was modified to simulate L5-S1 interbody fusion fixed with a pedicle screw system. An interspinous spacer, Device for Intervertebral Assisted Motion (DIAM), was used as a topping-off device and placed between interspinous processes of the L4 and L5 segments. Range of motion (ROM), von-Mises stress distribution, and ligament strain at SIJ were compared between fusion (without DIAM) and topping-off (fusion with DIAM) models under moments of four physiological motions. RESULTS ROM at the left and right SIJs in the topping-off model was higher by 26.9% and 27.5% in flexion, 16.8% and 16.1% in extension, 18.8% and 15.8% in lateral bending, and 3.7% and 7.4% in axial rotation, respectively, compared to those in the fusion model. The predicted stress and strain data showed that under all physiological loads, the topping-off model exhibited higher stress and ligament strain at the SIJs than the fusion model. CONCLUSIONS Motion, stress, and ligament strain at SIJ increase when supplementing lumbosacral fusion with topping-off devices, suggesting that topping-off surgery may be associated with higher risks of SIJ degeneration and pain than fusion alone.
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Affiliation(s)
- Wei Fan
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China.
| | - Chi Zhang
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Qing-Dong Wang
- Department of Mechanical Engineering, Tsinghua University, Beijing, China
| | - Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Ming Zhang
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong, China; Research Institute for Sports Science and Technology, The Hong Kong Polytechnic University, Hong Kong, China
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Effect of Interbody Implants on the Biomechanical Behavior of Lateral Lumbar Interbody Fusion: A Finite Element Study. J Funct Biomater 2023; 14:jfb14020113. [PMID: 36826912 PMCID: PMC9962522 DOI: 10.3390/jfb14020113] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/30/2023] [Accepted: 02/10/2023] [Indexed: 02/22/2023] Open
Abstract
Porous titanium interbody scaffolds are growing in popularity due to their appealing advantages for bone ingrowth. This study aimed to investigate the biomechanical effects of scaffold materials in both normal and osteoporotic lumbar spines using a finite element (FE) model. Four scaffold materials were compared: Ti6Al4V (Ti), PEEK, porous titanium of 65% porosity (P65), and porous titanium of 80% porosity (P80). In addition, the range of motion (ROM), endplate stress, scaffold stress, and pedicle screw stress were calculated and compared. The results showed that the ROM decreased by more than 96% after surgery, and the solid Ti scaffold provided the lowest ROM (1.2-3.4% of the intact case) at the surgical segment among all models. Compared to solid Ti, PEEK decreased the scaffold stress by 53-66 and the endplate stress by 0-33%, while porous Ti decreased the scaffold stress by 20-32% and the endplate stress by 0-32%. Further, compared with P65, P80 slightly increased the ROM (<0.03°) and pedicle screw stress (<4%) and decreased the endplate stress by 0-13% and scaffold stress by approximately 18%. Moreover, the osteoporotic lumbar spine provided higher ROMs, endplate stresses, scaffold stresses, and pedicle screw stresses in all motion modes. The porous Ti scaffolds may offer an alternative for lateral lumbar interbody fusion.
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Sun B, Han Q, Sui F, Zhang A, Liu Y, Xia P, Wang J, Yang X. Biomechanical analysis of customized cage conforming to the endplate morphology in anterior cervical discectomy fusion: A finite element analysis. Heliyon 2023; 9:e12923. [PMID: 36747923 PMCID: PMC9898605 DOI: 10.1016/j.heliyon.2023.e12923] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 12/28/2022] [Accepted: 01/09/2023] [Indexed: 01/13/2023] Open
Abstract
In anterior cervical discectomy and fusion (ACDF), an interbody fusion device is an essential implant. An unsuitable interbody fusion device can cause postoperative complications, including subsidence and nonunion. We designed a customized intervertebral fusion device to reduce postoperative complications and validated it by finite element analysis. Herein, we built a non-homogeneous model of the C3-7 cervical spine. Three implant models (customized cage, commercial cage, and bone graft cage) were constructed and placed in the C45 cervical segment after ACDF surgery. The simulated range of motion (ROM), stress at the cage-bone interface, and stress on the cage and implants were compared under different conditions. The commercial cage showed maximum stress peaks at 40.3 MPa and 43.2 MPa in the inferior endplate of C4 and superior endplate of C5 under rotational conditions, higher compared to 29.7 MPa and 26.4 MPa, respectively, in the customized cage. The ROM was not significantly different between the three cages placed after ACDF. The stresses on the commercial cage were higher compared to the other two cages under all conditions. The bone graft in the customized cage was subject to higher stress than the commercial cage under all conditions, particularly lateral bending, wherein the maximum stress was 5.5 MPa. These results showed that a customized cage that better conformed to the vertebral anatomy was promising for reducing the risk of stress shielding and the occurrence of subsidence.
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Yu Z, Thakolkaran P, Shea K, Stanković T. Artificial neural network supported design of a lattice-based artificial spinal disc for restoring patient-specific anisotropic behaviors. Comput Biol Med 2022. [DOI: 10.1016/j.compbiomed.2022.106475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Huang ZB, Nie MD, Zhang NZ, Liu S, Yuan JB, Lin XM, Cheng CK, Shi ZC, Mao NF. Biomechanical evaluation of a short-rod technique for lumbar fixation surgery. Front Bioeng Biotechnol 2022; 10:959210. [PMID: 36032712 PMCID: PMC9403742 DOI: 10.3389/fbioe.2022.959210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Objective: The purpose of this study was to analyze the stability and instrument-related complications associated with fixation of the lumbar spine using the Short-Rod (SR) technique. Methods: Using finite element analysis, this study assessed the stability of a bilateral lumbar fixation system when inserting the pedicle screws at angles of 10°, 15°, and 20° to the endplate in the sagittal plane. Using the most stable construct with a screw angle, the model was then assessed with different rod lengths of 25, 30, 35, and 45 mm. The optimal screw inclination angle and rod length were incorporated into the SR model and compared against traditional parallel screw insertion (pedicle screws in parallel to the endplate, PPS) in terms of the stability and risk of instrument-related complications. The following parameters were evaluated using the validated L4–L5 lumbar finite element model: axial stiffness, range of motion (ROM), stress on the endplate and facet joint, von-Mises stress on the contact surface between the screw and rod (CSSR), and screw displacement. Results: The results showed that the SR model with a 15° screw inclination angle and 35 mm rod length was superior in terms of construct stability and risk of complications. Compared to the PPS model, the SR model had lower stiffness, lower ROM, less screw displacement, and lower stress on the facet cartilage, the CSSR, and screws. However, the SR model also suffered more stress on the endplate in flexion and lateral bending. Conclusion: The SR technique with a 15° screw inclination and 35 mm rod length offers good lumbar stability with a low risk of instrument-related complications.
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Affiliation(s)
- Ze-Bin Huang
- Department of Spine Surgery, First Affiliated Hospital of Naval Medical University, Shanghai, China
| | - Mao-Dan Nie
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Ning-Ze Zhang
- Key Laboratory of Biomechanics and Mechanobiology, Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Shu Liu
- Department of Spine Surgery, First Affiliated Hospital of Naval Medical University, Shanghai, China
| | - Jia-Bin Yuan
- Department of Spine Surgery, First Affiliated Hospital of Naval Medical University, Shanghai, China
| | - Xu-Miao Lin
- Department of Spine Surgery, First Affiliated Hospital of Naval Medical University, Shanghai, China
| | - Cheng-Kung Cheng
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- *Correspondence: Cheng-Kung Cheng, ; Zhi-Cai Shi, ; Ning-Fang Mao,
| | - Zhi-Cai Shi
- Department of Spine Surgery, First Affiliated Hospital of Naval Medical University, Shanghai, China
- *Correspondence: Cheng-Kung Cheng, ; Zhi-Cai Shi, ; Ning-Fang Mao,
| | - Ning-Fang Mao
- Department of Spine Surgery, First Affiliated Hospital of Naval Medical University, Shanghai, China
- *Correspondence: Cheng-Kung Cheng, ; Zhi-Cai Shi, ; Ning-Fang Mao,
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Guo T, Zhang X, Hu Y, Lin M, Zhang R, Chen X, Yu D, Yao X, Wang P, Zhou H. New Hope for Treating Intervertebral Disc Degeneration: Microsphere-Based Delivery System. Front Bioeng Biotechnol 2022; 10:933901. [PMID: 35928951 PMCID: PMC9343804 DOI: 10.3389/fbioe.2022.933901] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 06/13/2022] [Indexed: 12/04/2022] Open
Abstract
Intervertebral disc (IVD) degeneration (IVDD) has been considered the dominant factor in low back pain (LBP), and its etiological mechanisms are complex and not yet fully elucidated. To date, the treatment of IVDD has mainly focused on relieving clinical symptoms and cannot fundamentally solve the problem. Recently, a novel microsphere-based therapeutic strategy has held promise for IVD regeneration and has yielded encouraging results with in vitro experiments and animal models. With excellent injectability, biocompatibility, and biodegradability, this microsphere carrier allows for targeted delivery and controlled release of drugs, gene regulatory sequences, and other bioactive substances and supports cell implantation and directed differentiation, aiming to improve the disease state of IVD at the source. This review discusses the possible mechanisms of IVDD and the limitations of current therapies, focusing on the application of microsphere delivery systems in IVDD, including targeted delivery of active substances and drugs, cellular therapy, and gene therapy, and attempts to provide a new understanding for the treatment of IVDD.
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Affiliation(s)
- Taowen Guo
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, China
- Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, China
| | - Xiaobo Zhang
- Department of Spine Surgery, Honghui Hospital, Xi’an Jiaotong University, Xi’an, China
- *Correspondence: Haiyu Zhou, ; Xiaobo Zhang,
| | - Yicun Hu
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, China
- Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, China
| | - Maoqiang Lin
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, China
- Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, China
| | - Ruihao Zhang
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, China
- Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, China
| | - Xiangyi Chen
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, China
- Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, China
| | - Dechen Yu
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, China
- Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, China
| | - Xin Yao
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, China
- Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, China
| | - Peng Wang
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, China
- Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, China
| | - Haiyu Zhou
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, China
- Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, China
- Xigu District People’s Hospital, Lanzhou, China
- *Correspondence: Haiyu Zhou, ; Xiaobo Zhang,
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Mechanical Model and FEM Simulations for Efforts on Biceps and Triceps Muscles under Vertical Load: Mathematical Formulation of Results. MATHEMATICS 2022. [DOI: 10.3390/math10142441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Although isometric contractions in human muscles have been analyzed several times, there are no FEA models that allow us to use the same modeled joint (the elbow under our case) in different conditions. Most elbow joints use 3D elements for meshing. Representing the muscles in the joint is quite useful when the study is focused on the muscle itself, knowing stress distribution on muscle, and checking damage in muscle in a detailed manner (tendon–muscle insertion, for example). However, this technique is not useful for studying muscle behavior at different positions of the joint. This study, based on the mechanical model of the elbow joint, proposes a methodology for modelling muscles that will be studied in different positions by meshing them with 1D elements. Furthermore, the methodology allows us to calculate biceps and triceps efforts under load for different angles of elbow joint aperture. The simulation results have been mathematically modelled to obtain general formulations for these efforts, depending on the load and the aperture angle.
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