摘要目的 利用三维有限元模型初步评价经皮前路腰骶轴向融合(AxiaLIF)螺钉的生物力学性能并临床应用提供依据.方法 利用Unigraphics软件对螺钉进行计算机建模,并且以iges格式导入到有限元分析软件ANSYS中进行有限元建模,根据临床实际将建立好的螺钉有限元模型与从"中国力学虚拟人"模型库中选择的完整人体L5-S1的有限元模型有效整合,分析不同工况下螺钉的应力分布情况.结果 3种工况下螺钉应力峰值:垂直载荷为175.334 Mpa、扭转载荷为183.765 Mpa和侧弯载荷为146.237 Mpa.螺钉总体应力均较小,以椎间融合部为中心,上、下3～5个螺纹内局部应力稍高,应力峰值最高值均位于螺钉注射孔下第一个螺纹内.3种工况之间比较,以扭转载荷下应力为最高,垂直载荷次之,侧弯载荷下螺钉所受应力为最小.结论 腰骶螺钉强度可以满足人体日常垂直压缩,扭转,侧弯等要求,可进行临床进一步应用.

abstractsObjective To establish a 3D finite element model of L5/S1 motion segment with percutaneous axial lumbosacral interbody fusion (AxiaLIF) screw and conduct a preliminary analysis of biomechanical stress. Methods The titanium screw was implanted in L5 and S1 vertebral body. Solid model was established by CAD software according to the actual dimensions of screw. Then computer graphics were obtained from iges format and imported into the finite element analysis software to establish the finite element model. With the aid of Mechanical Virtual Human of China, a 3D finite element model of L5/S1 motion segment with AxiaLIF screw was established. Vertical compression, torque moment and bending moment were loaded respectively on the upper surface of L5 vertebrae to simulate the load stress in human body. Stress distribution of screw was obtained. Results Generally stress values were relatively low. Peak stresses of screw under three loading conditions were 175. 334 Mpa, 183. 765 Mpa and 146. 237 Mpa respectively. Stress value was relatively high at the central part of interbody fusion. And all the highest values were localized at the first thread below the central part. Result of comparison between three conditions; torque load was the highest, followed by vertical load and lateral bending. Conclusion Percutaneous axial lumbosacral screw can meet the normal loading conditions. Further clinical applications are recommended.