颈椎半椎板切除后小关节部位的应力分析

根据CT数据建立了颈椎C4-C6功能节段的三维非线性有限元完整模型,并在此模型基础上建立了椎板切除模型。考察了椎板半切除术对小关节的生物力学影响。将C6椎体下表面固定作为边界条件,采用三种加载模式,即于C4椎体上表面施加1.8Nm分别沿矢状面、冠状面、轴面方向的纯弯矩。通过计算得到了C5半椎板切除后小关节部位的应力变化。结果表明,半椎板切除手术对各加载模式下小关节面的Von Mises应力有较大的影响,应力变化最大处应力上升了187.5%。评价颈椎半椎板切除术不能忽视手术对小关节的影响。

Stress Analysis of Facets after Cervical Laminectomy

To investigate the biomechanical effects on the facets post-laminectomy,a three-dimensional nonlinear intact C4-C6 FEY(finite element) model was developed.The modified FE model was set up to simulate laminectomy for stress analysis.The inferior surface of C6 vertebra was constrained in all directions as boundary condition.Pure moment of 1.8Nm was applied over the top surface of C4 vertebra to simulate the movements of cervical spine under flexion,extension,lateral bending and axial rotation respectively.Results showed that there were apparent effects on facets under the above different loads after laminectomy.The stress was increased by a maximum of 187.5%.A conclusion can be drawn that the influences on the facets post-surgery should be considered when making a biomechanical evaluation on laminectomy.