椎板不同切除范围对腰椎生物力学影响的有限元分析

建立全腰椎有限元模型,模拟三种后路手术方式,分析不同椎板切除范围对腰椎生物力学的影响。综合利用三维重建自编软件和Hyper Mesh软件,建立腰椎(L1-L5)有限元模型并与前人所作体外实验数据比较,验证本模型的有效性。在此基础上模拟全椎板切除、半椎板切除及椎板开窗减压术,比较减压节段的运动范围及相应椎间盘的应力改变。L3-4、L4-5节段后部结构切除后,腰椎运动范围与椎板切除大小成正比,纤维环应力最大变化发生在前屈、后伸和左右旋转运动时,而在侧屈运动时无明显的变化。腰椎运动范围的增加与腰椎后部结构的切除程度有关。在彻底减压的同时,最大程度的保留腰椎后部结构,可以减小术后椎间盘应力,减轻关节突等结构的进一步退变。

Biomechanical research on different pairs of lumbar laminectomy with finite element analysis

The finite element model of the intact lumbar spine (L1-L5) was set up to study the biomechanical changes of three different pairs of the lumbar laminectomy. The three-dimensional finite elements model of L1-L5 vertebrae structure was constructed by the combination of self-compiled software and Hyper Mesh. The finite element model was compared with the experimental data in vitro. The finite element model was modified of stenosis at L3-L4 and L4-L5 with the same boundary conditions and physical loads to study the motion and loading in the annulus changes at the surgical site as a result of surgical alteration. The study suggested that the removal of posterior lumbar spinal elements for the treatment of stenosis at L3-L4 and L4-L5 produced a graded increase in motion at the surgical site, with the greatest changes occurring in flexion-extension and axial rotation and that during lateral bending the amount of resection was only slightly affected. The data showed that for flexion-extension and axial rotation the increases in motion were correlated to the extent of posterior element removal. It is necessary to retain the greatest degree of posterior lumbar structures in thorough decompression, which can further reduce the postoperative intervertebral disc, facet degeneration.