腰椎单节段术后失稳三维有限元模型的建立

目的建立腰椎L4-5单节段退变模型,模拟腰椎后路椎板减压术(后部结构分级切除)建立术后不同程度失稳有限元模型,为进一步开展腰椎失稳的生物力学研究奠定基础。方法利用交互式医学图像控制系统MIMICS软件对健康志愿者腰椎的薄扫CT图像进行预处理,建立L4-5节段完整三维模型,并进行面网格化,在此基础上模拟手术分级切除L4-5椎体后部结构,进一步建立L4-5节段术后不同程度的失稳模型,再将面网格化的三维模型导入ABAQUS软件进行体网格化,并定义材料及截面属性、定义韧带及其属性、定义椎体间以及椎体与椎间盘相互作用,并加载载荷进行计算。结果成功建立了腰椎单节段后路椎板减压术术后不同程度失稳的三维有限元模型,几何相似性好,经验证模型有效,计算可收敛。结论腰椎单节段术后失稳三维有限元模型具有良好的生物逼真度,适用于临床科研分析,为进一步生物力学研究奠定了良好的模型基础。

Three dimensional finite element models of postoperative single-segmental lumbar spinal instability after graded laminectomy

Objective To build a 3D finite element model of single-segmental degenerative lumbar spine and simulate posterior graded laminectomy,and establish different 3D finite element models of posterior L4-5 segmental instability for the further study of biomechanical analysis.Methods C1-S1 segment data were obtained from computed tomography（CT） scans of healthy male.A three-dimensional finite element model of degenerative L4-5 segment was built in the MIMICS and the ABAQUS software.And the different 3D finite element models of posterior L4-5 segmental instability were established after graded laminectomy and facetectomy in the MIMICS software.These models were composed of the bony vertebrae,articulating facets,intervertebral disc,and associated ligaments,The basic stress analysis of L4-5 segment motion segment was made under the considerations of different material properties of bone,ligaments and facet joints contacting frictional property.Results The finite element model of degenerative L4-5 segment was built successfully.And the 3D finite element models of postoperative L4-5 segmental graded instability were also constructed successfully.These models had good geometric similarity,and preliminary test results showed that these models were effective.Conclusion The effective 3D finite element models of postoperative L4-5 motion segmental graded instability had good biological fidelity,be suitable for clinical research analysis.