基于CAD技术的个体化退变腰椎有限元模型库的建立

目的根据退变腰椎的形态特征,采用计算机辅助设计（computer aided design,CAD）方法精确建立不同形态改变的退变腰椎L4-L5运动节段三维有限元模型。方法采用改良的“非种子区域分割”以及非平行“最佳切割平面”等一系列新型CAD方法精确建立包括终板凹陷角、椎间盘高度、腰椎小关节角及椎间盘前凸角改变的L4-L5节段表面模型基本“结构模块”,表面模型数据导入ANSYS获得各“结构模块”有限元模型后,通过界面间的拼接粘贴构建不同形态改变的退变腰椎有限元模型并进行充分加载验证。结果所构建的有限元模型包含L4-L5节段所有重要解剖结构,正常和退变腰椎有限元模型预测结果与体外实验生物力学研究结果相符合。结论基于CT数据的新型CAD方法实现了个体化退变腰椎有限元模型库的建立。

Establishment of individually finite element models libraries of degenerative lumbar spine basing CAD technique

Objective Three-dimensional finite element (FE) models of the degenerative lumbar L4-L5 segment with different morphological characteristics were developed using computer aided design (CAD) technique. Methods A series of new effective CAD methods such as modified "no-seed region segmentation" and non-parallel "best cross-section planes" were used to accurately establish of basic "fabric module" of the lumbar surface model representing the variation of endplate angle, disc height, facet joint angle and the lordosis angle of the intervetebral disc, After importing data of the models into ANSYS for the three-dimensional FE mesh construction different kinds of intact and degeneration lumbar FE models were established by jainting and stickup the surfaces and validated under different loading configurations. Results All of the important anatomical structures of lumbar L4-L5 segment can be represented by the established FE models. The predicted results of intact and degenerative L4-L5 segment FE models were closely correlated with published experimental data. Conclusion New CAD method based on CT data realized the establishment of individual FE model libraries of degenerative lumbar spine.