Abstract: Objective To study the biomechanical character of intervertebral disc in different loadings of axial compression, flexion, lateral bending, extension, rotation to develop the finite element (FE) of human lumbar L3-5 segment. Methods According to CT radiological data of a healthy adult, the vertebra and intervertebral disc of lumbar L3-5 segment were respectively reconstructed by Mimics 10.0 software and Geomagic 10.0 software. The FE model of L3-5 segment was reconstructed, and intact disc and herniated lumbar disc were created by adding the lumbar attaching ligaments into the simulating model and changing the corresponding material properties after the disc was extruded in Ansys software. The biomechanical characteristics of two models were simulated under the five loadings of axial compression, flexion, lateral bending, extension and rotation by FE method. Results After the L3, 4 lumbar disc was extruded, the stress distribution on the disc and the ability of load transfer were changed. The stress was concentrated in the posterior lateral of annulus fibrous. Conclusion After the disc was extruded, the load-bearing capacity decreased.

Key words: Lumbar vertebrae, Biomechanics, Intervertebral disk displacement, Stress, mechanical, Finite element analysis

摘要： 目的  建立人体腰椎运动节段（L3 ~ 5）有限元模型，于轴向正压力、前屈、侧弯、后伸及旋转等载荷下研究椎间盘的生物力学特征。方法  根据健康成年人腰椎运动节段（L3 ~ 5）的CT 影像学资料，采用Mimics 10.0 医学图像处理软件和Geomagic 10.0 逆向工程软件分别建立腰椎运动节段（L3 ~ 5）椎体和椎间盘的几何模型，Ansys 软件附加腰椎相关韧带及通过改变椎间盘突出后对应的材料属性，构建正常模型和腰椎间盘突出（L3-4）模型，运用有限元方法模拟正常椎间盘和突出椎间盘于轴向正压力、前屈、侧弯、后伸和旋转等载荷下生物力学特征参数。结果  腰椎运动节段（L3，4）发生椎间盘突出后即改变了椎间盘的应力分布及传递载荷能力，应力主要集中于纤维环之后外侧。结论  腰椎运动节段（L3-4）椎间盘突出后椎间盘的承载功能明显下降。

关键词: 腰椎, 生物力学, 椎间盘移位, 应力, 物理, 有限元分析