退行性变性腰椎滑脱的有限元模型研究

Study on finite element model of degenerative lumbar spondy-lolisthesis

目的:应用有限元方法,研究退行性变性腰椎滑脱的应力分布。方法:建立退行性变性腰椎滑脱节段的有限元力学模型,模拟不同体位下的加载,计算和分析滑脱节段各部应力分布。结果:①腰段脊柱发生滑脱后,下位椎体在Z轴上的应力前移。②椎间盘的剪切应力主要分布在纤维环。③小关节的平均剪切应力明显高于椎间盘。④峡部应力集中。结论:腰椎退行性变性滑脱时,下位椎体对重力的承载部位前移;小关节成为剪切应力的主要承载者;峡部最具被破坏的可能性。

AIM:To study the stress distribution of the degenerative lumbar spondylolisthe sis by using finite element analysis. METHODS:A mechanical finite element model of lumbar spondylolisthesis was set up. When the relative loading was added on the model, the condtions of different postures were imitated,and the stress distributions of each segment of the spon dylolisthesis were calculated and analyzed. RESULTS:①After spondylolisthesis generated,the compressive stress of lower ve rtera on the Z axis moved to the anterior segment.②The shear stress in interver tebral disc mainly distributed in fibrous rings.③The average shear stress on th e facet joints was obviously higher than that on intervertebral disc.④Von Mises stress on the pars interarticularis was intensive.CONCLUSION:After retrograde degenerated lumbar spine displacing toward anterio r,the compressive stress transfers the posterior parts to the anterior parts of the lower vertebral,shear stress mostly distributes in facet joints,and the pars interarticularis has the greatest possibility to be destroyed.