椎间盘退变对L4-L5在垂直载荷下生物力学行为特性的影响

Effects of Intervertebral Disc Degeneration on Biomechanics Behavior Characteristics of L4-L5 Under the Vertical Load

利用三维绘图软件构建人体腰椎L4-L5节段几何模型,采用有限元分析方法并调整计算精度,模拟研究椎间盘发生退变等四种工况,如轻度退变、中度退变、重度退变以及椎间盘完全摘除时关节峡部的受力情况。通过施加在L4椎板上378.93N的垂直载荷,得到四种工况下关节峡部的应力云图。结果表明,椎间盘退变程度影响小关节处的接触面积,从而使关节峡部应力发生相应的变化。说明关节峡部是腰椎后部抗压的重要结构,而关节峡部应力分布与大小以及腰椎后部结构刚度大小和小关节处的接触面积有关。该结论可为脊柱生物力学分析及人工椎间盘置换提供一定的理论参考依据。

A geometrical model of L4-L5 lumbar segment was constructed using a three-dimensional graphics software.Four conditions of the degenerated discs,i.e.light degeneration,moderate degeneration,severe degeneration and complete excision degeneration,were simulated with loading situations using finite element method under the condition of appropriate computational accuracy.By applying a vertical load of 378.93 Non L4vertebral plate,stress nephograms on joint isthmus under four different working conditions were obtained.The results showed that the contacted area of facet joint was influenced by the degree of intervertebral disc degeneration level,which influenced the mises stress on joint isthmus.It was proved that joint isthmus was the important pressure-proof structure of the back of lumbar vertebra,and the stress values and distribution were related to structural stiffness of the back of lumbar vertebra as well as the contact area of facet joint.The conclusion could be the theoretical reference for the analysis of spinal biomechanics and artificial disc replacement as well.