非线性三维有限元法分析腰椎间盘退变  

Analysis of lumbar disc degeneration using three.dimensional nonlinear finite element method

作　　者：唐小君[1] 陈其昕[1] 刘耀升[1] 李方才[1] 

机构地区：[1]浙江大学医学院附属第二医院骨科,杭州310009

出　　处：《中华医学杂志》2008年第23期1634-1638,共5页National Medical Journal of China

基　　金：卫生部科学研究基金重点资助项目（WKJ2005-Z-046）

摘　　要：目的探讨椎间盘退变对腰椎活动节段生物力学的影响。方法采用新型的基于CT图像的CAD建模方法精确建立L4-L5运动节段的三维非线性有限元模型，并通过改变椎间盘材料特性和椎间盘高度等参数，建立正常椎间盘模型和轻、中、重度椎间盘退变模型，分别对4种有限元模型进行生物力学测试，比较4种模型之间刚度、髓核内压、后部结构力、纤维环基质最大应力的差异，并比较椎体、终板的应力分布变化。结果各种载荷条件下，退变椎间盘模型刚度均与正常椎间盘模型不同，其中轻度退变模型刚度小于正常模型，而中度退变模型和重度退变模型刚度大于正常模型，且重度退变模型刚度大于中度退变模型；与正常模型比较，轻度退变模型的后部结构力略有增大，而中度退变和重度退变模型的后部结构力逐渐减小；随着椎间盘退变程度的增加，髓核内压逐渐减小，纤维环基质最大von Mises应力渐行性增大，各指标在5种载荷下表现一致；随着椎间盘退变的加重，椎间盘承载向纤维环分散，椎体、终板外缘出现应力集中现象。结论椎间盘退变可导致腰椎活动节段刚度改变，轻度椎间盘退变引起腰椎刚度下降，而中、重度椎间盘退变时腰椎刚度增加；椎间盘退变时腰椎间盘承载与腰椎后部结构力呈现负相关变化；退变椎间盘的承载模式发生改变，椎间盘、椎体、终板应力分布存在向外周扩散的趋势。Objective To explore the effects of intervertebral disc degeneration on the biomechanical behavior of the lumbar motion segment. Methods A three-dimensional nonlinear finite element model of L4-L5 segment was established using CAD technique based on CT images. A normal disc model and three degenerative disc models were established by changing the parameters such as disc material properties and disc height. The effects of disc degeneration on the biomechanical properties, including stiffness, nucleus pressure, maximum von Mises stress in the annulus, and force of posterior structure were studied under two moment loads （ flexion and extension） and for three different direct forces （ compression, and anterior and posterior shear forces）, and the stress distribution of vertebral body and end-plate was also analyzed. Results The stiffness of the lightly degenerative disc model was decreased compared with that of the normal disc, while it was increased in the moderately and severely degenerative disc models when compared with the normal disc. The force of posterior structure in the lightly degenerative disc model was increased while the values of force of posterior structure in the moderately and severely degenerative disc models were decreased gradually. The maximum von Mises stress in the annulus increased, and the nucleus pressure decreased as the disc degeneration progressed. Moreover, the stress of intervertebral disc, vertebral body, and end-plate was distributed more peripherally. Conclusion Light degeneration of intervertebral disc leads to instability of lumbar spine, while the stability restores with further degeneration of disc. There is a negative correlation between the force of posterior structure and the load on the intervertebral disc. With the disc degeneration progressing, the intervertebral disc load pattern changes, the stress of intervertebral disc, vertebral body, and end-plate is concentrated peripherally.

关 键 词：椎间盘 生物力学 非线性三维有限元法 腰椎 

分 类 号：R686[医药卫生—骨科学]