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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0.75mm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mimics10.0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27130个,单元数113834,其中包括Solid单元113153个,Area161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。
OBJECTIVE: To establish a three-dimensional finite element model of early degeneration of L4-5 active segment based on CT, and to test its mechanical properties. Methods: A Chinese female volunteer aged 39 years old with lower lumbar pain was selected as a simulation object. The spinal column L4-5 was scanned continuously with 0.75mm slice thickness. A total of 138 CT tomographic images were obtained. Relevant data of the model. The CT scan of the lumbar spine images combined with human anatomy data by mimics10.0 software modeling L4-5 motion segment of the three-dimensional model, combined with CAD software CATIA the activity of the segment data optimization and the formation of a solid model. The model data into the finite element analysis software Patran converted into finite element model. Simulating the stress environment of this segment, four 100N forces were applied to the vertebral junction of the anterior and posterior vertebral body at the equatorial distance from the rotation axis of L4 vertebral body in the form of node load, respectively, to verify the accuracy of the model . Results: The finite element model of L4-5 segment with early degenerative lumbar spine was established. The total number of nodes in the model was 27130 with 113834 elements, including 113,153 Solid units, 161 Area units and 520 Link units. The mechanical tests showed that the load The uneven distribution of the disc, the weakness of the posterior annulus increased stress. Conclusion: High-precision three-dimensional finite element model of early degenerative lumbar spine motion segments can be established with high degree of automation through CT tomography, digital image processing and computer-aided design, and can be used for further study of spinal biomechanics.