Duan Yang, Jin Anmin, Zhang Hui, Min Shaoxiong, Hu Konghe
Department of Orthopaedics, Zhujiang Hospital, Southern Medical University, Guangzhou Guangdong 510282, PR China.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2010 Dec;24(12):1494-9.
To establish sophisticated three-dimensional finite element model of the lower cervical spine and reconstruct lower cervical model by different fixation systems after three-column injury, and to research the stress distribution of the internal fixation reconstructed by different techniques.
The CT scan deta were obtained from a 27-year-old normal male volunteer. Mimics 10.01, Geomagic Studio10.0, HyperMesh10.0, and Abaqus 6.9.1 softwares were used to obtain the intact model (C3-7), the model after three-column injury, and the models of reconstructing the lower cervical spine after three-column injury through different fixation systems, namely lateral mass screw fixation (LSF) and transarticular screw fixation (TSF). The skull load of 75 N and torsion preload of 1.0 N*m were simulated on the surface of C3. Under conditions of flexion, extension, lateral bending, and rotation, the Von Mises stress distribution regularity of internal fixation system was evaluated.
The intact model of C3-7 was successfully established, which consisted of 177 944 elements and 35 668 nodes. The results of the biomechanic study agreed well with the available cadaveric experimental data, suggesting that they were accord with normal human body parameters and could be used in the experimental research. The finite element models of the lower cervical spine reconstruction after three-column injury were established. The stress concentrated on the connection between rod and screw in LSF and on the middle part of screw in TSF. The peak values of Von Mises stress in TSF were higher than those in LSF under all conditions.
For the reconstruction of lower cervical spine, TSF has higher risk of screw breakage than LSF.
建立精确的下颈椎三维有限元模型，模拟下颈椎三柱损伤后采用不同固定系统进行重建，并研究不同技术重建内固定的应力分布。
选取一名27岁正常男性志愿者进行CT扫描获取数据。利用Mimics 10.01、Geomagic Studio10.0、HyperMesh10.0和Abaqus 6.9.1软件，构建完整模型（C3 - 7）、三柱损伤后模型以及三柱损伤后采用不同固定系统重建下颈椎的模型，即侧块螺钉固定（LSF）和经关节螺钉固定（TSF）。在C3表面模拟75 N的颅骨载荷和1.0 N·m的扭转预载荷。在屈伸、侧弯和旋转工况下，评估内固定系统的Von Mises应力分布规律。
成功构建C3 - 7完整模型，该模型由177 944个单元和35 668个节点组成。生物力学研究结果与现有的尸体实验数据吻合良好，表明其符合人体正常参数，可用于实验研究。建立了下颈椎三柱损伤后重建的有限元模型。LSF中应力集中在棒与螺钉的连接处，TSF中应力集中在螺钉中部。在所有工况下，TSF的Von Mises应力峰值均高于LSF。
在下颈椎重建中，TSF比LSF发生螺钉断裂的风险更高。
