脊柱腰段三维有限元模型的构建与椎间盘应力分析

Construction of three-dimensional finite element model of lumbar spine and stress analysis of intervertebral disc

目的建立正常脊柱腰段三维有限元模型,为生物力学研究及腰椎损伤研究提供可靠模型。方法采集1名健康成年男性脊柱腰段CT和MRI断层影像数据,应用Mimics软件依据CT数据对全部腰椎骨及骶骨上部进行三维模型重建,依据MRI数据对L 1~L 5椎间盘髓核进行三维模型重建。将椎骨与髓核进行空间配准,在此基础上建立椎间盘、关节囊和韧带的三维模型。在Ansys中划分网格并定义材料属性,对模型施加运动性载荷模拟脊柱腰段处于前屈、后伸、侧弯和扭转等运动工况下的生物力学特征,验证模型的有效性。结果建立了完整的脊柱腰段三维有限元模型,包含椎骨、椎间盘、骶骨上端、韧带、关节囊等重要结构,总节点数为104190个、总单元数为339165个。模型通过有效性验证,运动工况下的角位移范围和椎间盘的应力分布特点符合腰椎的生物力学特性。结论本研究建立的三维有限元模型仿真度高,可用于脊柱腰段的生物力学研究以及模拟疾病和手术对腰椎生物力学的影响。

Objective To establish a three-dimensional finite element model of normal lumbar spine,and provide a reliable model for biomechanical research and lumbar spine injury research.Methods CT and MRI data of lumbar spine of a healthy adult male were collected.The three-dimensional model of lumbar vertebrae and upper sacrum was reconstructed by Mimics software based on CT data.The three-dimensional model of L 1-L 5 disc nucleus pulposus was reconstructed by MRI data.The biomechanical characteristics of the lumbar spine under flexion,extension,lateral bending and torsion were simulated by applying exercise muscle loads to the model,and verify the validity of the model.Results A complete three-dimensional finite element model of lumbar spine was established,including the important structures of vertebra,intervertebral disc,upper sacrum,ligament and articular capsule.The total number of nodes was 104190,and the total number of elements was 339165.The angular displacement range and the stress distribution characteristics of the intervertebral disc under the condition of exercise were consistent with the biomechanical characteristics of the lumbar spine,which verifies the validity of the model.Conclusion The three-dimensional finite element model established in this study has a high degree of simulation,and can be used to study the biomechanics of the lumbar spine,to simulate effects of disease and surgery on biomechanics of lumbar spine.