人工椎间盘置换腰椎节段有限元模型的建立

目的：建立UL节段正常及人工腰椎间盘置换的三维有限元模型，用于进一步的腰椎生物力学研究。方法：取新鲜成人腰椎标本，通过螺旋CT扫描、图像数字化处理、三维图像重建技术及自由造型系统进行图像表面光滑处理，再对表面图像矢量化，转入有限元软件，建立L4／L5腰椎节段和SMH人工腰椎间盘的有限元模型，模仿腰椎前路椎间盘除术，建立人工腰椎间盘置换的三维有限元模型，用不同的材料参数仿真腰椎和人工椎间盘各结构特性。结果：建立了L4/L5节段人工腰椎间盘置换的有限元模型，模型由皮质骨、松质骨、椎间盘、韧带和人工椎间盘等结构组成。模型分为53452个单元，86329个结点，其中包括53408个固体单元，44个缆绳单元。结论：通过CT扫描可以获得准确的腰椎几何构型数据，并可在此基础上建立高仿真脊柱节段有限元模型。

Development of a three dimensional finite element model of lumbar motion segment with artificial disc replacement

Objective: To develop intact and artificial disc replacement altered three dimensional finite element model of L4/L5 for the study of lumbar spine biomechanical behavior. Methods: A fresh-frozen adult lumbar spine specimen was used for spiral computed tomography scanning. The geometric data of L4/L5 segment were obtained. We established a finite element model of L4/L5 by three dimensional image reconstruction and finite element software. The intact model was denucleated and implanted with SMH artificial intervertebral disc through anterior approach. Different material parameters were used to simulate structure properties of lumbar spine and artificial disc. Results: A finite element model of L4/L5 with artificial disc replacement was created. The model was composed of 53452 elements including 53408 eight-node solid elements and 44 two-node cable elements. Conclusions: Accurate geometric data of lumbar spine can be obtained through spiral computed tomography scanning and then we can establish a finite element model to simulate lumbar spine behavior.