个体化颈椎椎间融合器的三维有限元分析

Three-dimensional finite element analysis of individual cervical interbody fusion cage

目的探讨个体化颈椎椎间融合器(个体化Cage)的即刻稳定性及防下沉性能。方法提取1例神经根型颈椎病患者的颈椎CT骨三维数据,通过三维有限元前处理软件设计个体化Cage结构模型,使用三维有限元分析软件进行个体化Cage的有效性、即刻稳定性及防下沉性能分析。结果有限元模型在轴向压缩位移模拟上的预测结果与体外实验数据及学者们所建模型的预测结果无明显差异(P>0.05),而颈椎运动范围(ROM)角度模拟失真(P <0.05)。在轴向压缩、前屈、后伸及侧弯运动下,个体化Cage植入后C6椎体轴向压缩位移均明显减少,C6皮质骨与松质骨强度值得到提升(P <0.05);颈椎前屈、后伸及侧弯运动时刚度值明显增高(P <0.05),而在轴向压缩运动时刚度值无明显变化(P>0.05)。个体化Cage植入后,各结构在各方向颈椎运动中的最大Von-Mises应力均较前明显提升(P <0.05);应力云图可见C5、C6及个体化Cage均有应力集中区域,其压缩位移波动于0.03～0.11 mm之间。结论个体化Cage具有良好的即刻稳定性及防下沉性能。

Objective To investigate the immediate stability and anti-subsidence performance of the individual cervical interbody fusion cage.Methods Three-dimensional cervical vertebral CT data of 1 patient with cervical spondylotic radiculopathy were extracted,structural model of the individualized cervical intervertebral fusion cage was designed by 3D finite element pre-processing software,and its effectiveness,instant stability and anti-subsidence performance were evaluated by 3D finite element analysis software.Results Compared with experimental data in vitro or models built by some scholars,prediction results in the finite element model under the simulation of axial compression displacement showed no statistical differences(P>0.05),while the simulation distortion was found in angles of cervical range of motion(ROM,P<0.05).After the implantation of individual cage,axial compressive displacement of C6 vertebrae under axial compression,flexion,extension,and lateral bending motion were reduced significantly,and the strength values of C6 cortical bone and cancellous bone were also increased(P<0.05);Stiffness values under cervical flexion,extension and lateral bending were significantly higher(P<0.05),but in the axial compression movement,the stiffness values were not changed(P>0.05).When the individual cage was implanted,the maximum Von-Mises stress of each structure in each cervical vertebra movement was significantly higher than that before(P<0.05);The stress concentration region was found in C5,C6 and individual cage by the stress cloud image analysis,and the compression displacement fluctuated between 0.03 to 0.11 mm.Conclusion The individual cage has good immediate stability and anti-subsidence performance.