摘要
目的:建立寰枢椎后路椎弓根螺钉固定系统三维有限元模型,分析寰枢椎后路椎弓根螺钉固定的稳定性。方法:1例寰枢椎不稳标本行后路椎弓根螺钉系统固定,采用螺旋CT扫描,通过工作站将扫描获得的图像导入计算机中,利用ANSYS8.0软件建立寰枢椎不稳三维有限元模型。给予模型加载不同边界条件,模拟寰枢椎的不同运动,分析寰枢椎不稳采用后路椎弓根螺钉固定的稳定性。结果:寰枢椎不稳采用后路椎弓根螺钉系统固定在不同运动状态下应力主要集中在枢椎椎弓根螺钉的根部。前屈运动时,椎弓根螺钉根部的应力为0.350×109Pa,前屈角度为0.7°;后伸运动时,椎弓根螺钉根部的应力为0.427×109Pa,后伸角度为1.2°;侧弯运动时,椎弓根螺钉根部的应力为0.295×109Pa,侧弯角度为0.3°;旋转运动时,椎弓根螺钉根部的应力0.635×109Pa,旋转角度为0.8°。结论:寰枢椎不稳采用后路椎弓根螺钉系统固定具有良好的术后即时稳定性。
Objective： To develop a finite element model （FEM） ofatlantoaxial instability fixation with posterior pedicle screws and analyze its stability and stress distribution. Methods： The geometries from one specimen of the atlantoaxial instability fixation with posterior pedicle screws were determined through computer tomography images on the sagittal and coronal planes. These images of CT were transferred to PC, and the data from the images were then processed to make a finite element model of atlantoaxial instability by ANSYS 8.0 software. The finite element model was validated for loading in the flexion, extension, lateral bending and rotation, and then was used to evaluate the stress changes of the posterior pedicle screws fixation. Results： The FEM analysis showed that the stress distributed mainly in the base of the pedicle screw at the different motion states. When the model was underwent the anterior flexion motion, the maximum stress value was about 0.350×10^9 Pa, and the ROM of ante-flexion 0.7°. When the model was given the posterior extension motion, the maximum stress value was 0.427×10^9 Pa, and the ROM of post-extension 1.2°. At the lateral bending condition, the maximum stress value was 0.295×10^9 Pa, and the ROM of lateral bending 0.3°At the rotation condition, the maximum stress value was 0.635 ×10^9 Pa, and the ROM of rotation 0.8°. Conclusions： According to FEM analysis of the developed model, the posterior pedicle screw fixation for treating atlantoaxial instability will produce strong fixation and increase the stability immediately after the operation.
出处
《中国临床解剖学杂志》
CSCD
北大核心
2008年第5期539-542,共4页
Chinese Journal of Clinical Anatomy
关键词
寰枢椎不稳
椎弓根螺钉
有限元
atlantoaxial instability
pedicle screw
finite element
