Mo Zhongjun, Zhao Yanbin, Du Chengfei, Sun Yu, Zhang Ming, Fan Yubo
*School of Biological Science and Medical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, National Key Lab of Virtual Reality Technology, Beihang University, Beijing, P. R. China †Orthopaedic Department of Peking University Third Hospital, Beijing, P. R. China ‡Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong; and §National Research Center for Rehabilitation Technical Aids, Beijing, China.
Spine (Phila Pa 1976). 2015 Apr 15;40(8):E469-75. doi: 10.1097/BRS.0000000000000818.
A 3-dimensional finite element investigation.
To compare the biomechanical performances of different rotation centers (RCs) in the prevalent artificial cervical discs.
Various configurations are applied in artificial discs. Design parameters may influence the biomechanics of implanted spine. The RC is a primary variation in the popular artificial discs.
Implantation of 5 prostheses was simulated at C5-C6 on the basis of a validated finite element cervical model (C3-C7). The prostheses included ball-in-socket design with a fixed RC located on the inferior endplate (BS-FI) and on the superior endplate (BS-FS), with a mobile RC at the inferior endplate (BS-MI), dual articulation with a mobile RC between the endplates (DA-M), and sliding articulation with various RCs (SA-V). The spinal motions in flexion and extension served as a displacement loading at the C3 vertebrae.
Total disc replacements reduced extension moment. The ball-in-socket designs required less flexion moment, whereas the flexion stiffness of the spines with DA-M and SA-V was similar to that of the healthy model. The contributions of the implanted level to the global motions increased in the total disc replacements, except in the SA-V and DA-M models (in flexion). Ball-in-socket designs produced severe stress distributions in facet cartilage, whereas DA-M and SA-V produced more severe stress distribution on the bone-implant interface.
Cervical stability was extremely affected in extension and partially affected in flexion by total disc replacement. With the prostheses with mobile RC, cervical curvature was readjusted under a low follower load. The SA-V and BS-FS designs exhibited better performances in the entire segmental stiffness and in the stability of the operative level than the BS-MI and BS-FI designs in flexion. The 5 designs demonstrated varying advantages relative to the stress distribution in the facet cartilages and on the bone-implant interface.
三维有限元研究。
比较常见人工颈椎间盘不同旋转中心（RC）的生物力学性能。
人工椎间盘有多种构型。设计参数可能影响植入脊柱的生物力学。旋转中心是常见人工椎间盘中的一个主要变量。
基于经过验证的有限元颈椎模型（C3 - C7），在C5 - C6模拟植入5种植入物。这些植入物包括球窝设计，其固定旋转中心位于下终板（BS - FI）和上终板（BS - FS），下终板有活动旋转中心（BS - MI），终板间有活动旋转中心的双关节设计（DA - M），以及具有不同旋转中心的滑动关节设计（SA - V）。颈椎屈伸运动作为C3椎体的位移载荷。
全椎间盘置换降低了伸展力矩。球窝设计所需的屈曲力矩较小，而采用DA - M和SA - V的脊柱的屈曲刚度与健康模型相似。在全椎间盘置换中，除SA - V和DA - M模型（在屈曲时）外，植入节段对整体运动的贡献增加。球窝设计在小关节软骨中产生严重的应力分布，而DA - M和SA - V在骨 - 植入物界面产生更严重的应力分布。
全椎间盘置换在伸展时对颈椎稳定性影响极大，在屈曲时部分影响颈椎稳定性。对于具有活动旋转中心的植入物，在低跟随载荷下颈椎曲度会重新调整。在屈曲时，SA - V和BS - FS设计在整个节段刚度和手术节段稳定性方面比BS - MI和BS - FI设计表现更好。这5种设计在小关节软骨和骨 - 植入物界面的应力分布方面表现出不同的优势。
5级。
