复杂性腰椎管狭窄症的有限元建模与分析

目的精确建立复杂性腰椎管狭窄症(lumbar spinal stenosis,LSS)的退变腰椎全节段有限元模型,与正常模型进行对比。方法选取复杂性LSS患者采集CT数据,采用专用生物力学软件建立退变腰椎全节段模型,同时构建正常材质和几何形态的腰椎模型,用相同边界条件进行对比分析。结果复杂性LSS腰椎的刚度增加、活动度范围比正常模型要小,特别是后伸工况减少了25.4%。总体上,退变腰椎的应力有增大趋势,退变节段椎间盘L4～L5和邻近上位椎间盘L3～L4的终板、髓核和和维环基质应力分布趋向四周边缘集中,特别是基质应力最大增加129%。结论复杂性腰椎管狭窄症的腰椎有限元模型的活动度减少、刚度增加,退变椎间盘四周出现应力集中,促进邻近椎间盘退变。

Finite element modeling and analysis of complicated lumbar spinal stenosis

Objective To establish an accurate finite element(FE) model of complete lumbar spine with complicated lumbar spinal stenosis(LSS),then compare and analyze with normal model.Methods A woman with diagnosed complicated LSS was enrolled in this study after her agreement of informed consent.Her CT scan data were collected.By using specially designed modeling system,a complete FE model of the lumbar with complicated LSS was generated,as well as comparing lumbar model with normal material and geometry.Then,same boundary conditions were applied to do comparison.Results The results demonstrated that the complicated LSS model was stiffer,and its active movement range decreased by 25.4% compared to normal model.Generally,the stress in the complicated LSS model intended to increase.There were stress concentration around the endplate and disk at the degenerative intervertebral disc L4-L5 and adjacent disc L3-L4.And the maximum Mises stress of the anulus fibrosus was increased by 129%.Conclusion The lumbar spine with complicated LSS has less range of motion and is stiffer compared to normal model,and there are stress concentration at the degenerative intervertebral disc and adjacent intervertebral disc.The analysis result is useful to practical clinical diagnosis of lumbar spine with LSS.