基于CT建立早期退变腰椎活动节段的三维有限元模型

目的:基于CT建立了脊柱L4-5活动节段早期退变的三维有限元模型,并对其进行力学性能测试.方法:选择1名39岁慢性下腰部疼痛的中国女性志愿者作为模拟对象,对其脊柱L4-5节段进行层厚0.75 mm的连续扫描,共获得CT断层图像138幅,获取用于建立三维模型的相关数据.将CT扫描的腰椎图像结合人体解剖学数据通过mimics 10.0软件建模形成L4-5运动节段的三维模型后,结合CAD软件CATIA对该活动节段进行数据优化,并形成实体模型.将模型数据导入有限元分析软件Patran转换成有限元模型.模拟中立位该节段的受力环境,将4个100N力以结点负荷形式分别施加于L4椎体旋转轴等距离的内前外后部椎体结点,以观察验证该模型的准确性.结果:建立了腰椎早期退变的L4-5节段的有限元模型,模型总节点数为27 130个,单元数113 834,其中包括Solid单元113 153个,Area 161个,Link单元520个,力学测试显示负荷在椎间盘分布不均,薄弱的纤维环后部受力增加.结论:通过CT断层扫描、图像数字化处理及计算机辅助设计等方法,可以以自动化程度较高的方法建立腰椎早期退变活动节段的高精度三维有限元模型,用于脊柱生物力学的进一步研究.

Three dimension finite element model of the earlier-period degeneration lumbar motion segments reconstruced from CT images

Objective:To develop and validate a three dimension finite element model of the earlier-period degeneration L4-5 lumbar motion segments reconstruced from CT Images.Method:To develop such FE model,a 138 frames of CT images with the distance 0.75 mm were gathered in clinic,from which the plane coordinate data were obtained,and then these 2D data were transformed into 3D coordinate.Finally,the 3D FE model of a Chinese woman the earlier-period degeneration L4-5 lumbar motion segment was developed using Patran analysis software,and then the model was validate by a 400N stress force.Results:The result shows that the model has good effect visually and mathematically,which was consisted of 27 130 nodes,113 834 elements,including Solid elements 113 153,Area elements 161,Link elements 520.The results of load test of the aforementioned FE model was consistented the published results.Conclusion:Based on CT image and with the help of CAD methods,this three dimension finite element model of the earlier-period degeneration L4-5 lumbar motion segments can be constructed automatically with excellent simulation results.