自制椎板钩分散椎弓根螺钉系统应力作用的有限元分析  

A finite element analysis on stress change of spinal pedicle screw system after adding laminal hook

作　　者：汪宇[1] 潘滔[2] 刘先银[1] 周希平[3] 

机构地区：[1]东莞市人民医院骨科,广东省东莞市523018 [2]中山大学附属第一医院骨科,广东省广州市510080 [3]华南理工大学交通学院力学实验中心,广东省广州市510641

出　　处：《中国组织工程研究与临床康复》2007年第22期4292-4295,共4页Journal of Clinical Rehabilitative Tissue Engineering Research

基　　金：2002年度广东省科技计划重点项目资助(2002C30206)~~

摘　　要：目的:观察加用自制椎板钩对分散椎弓根螺钉系统应力的作用。方法:实验于2005-10-20在华南理工大学交通学院力学实验中心完成。①建立自行设计的新型椎板钩钉系统有限元模型:椎弓根螺钉长度为40mm,圆棒长度120mm,二者直径均为6mm,椎板钩高度为9mm,长度为22mm。②有限元模型建立:根据以上参数,应用ANSYS8.0软件,按实际大小和结构以二维线梁单元BEAM188建立新型椎板钩钉系统有限元模型,约束尾侧椎弓根螺钉和尾侧椎板钩内表面,垂直于头侧椎弓根螺钉进行加载。③应力测量:前屈扭矩5N·m状态下,对椎弓根螺钉系统不加与加用椎板钩时,整个系统各处的应力变化进行评估。结果:加钩后整个系统受力点增加,受力更加均匀。临床上容易发生断钉的部位应力显著降低。头、尾侧椎弓根钉根部加钩后轴向应力显著降低,以尾侧钉为著,降低37.08%。头、尾侧钉棒连接处加钩后剪切应力下降明显,头侧下降44.02%,尾侧下降60.71%。结论:椎板钩使得椎弓根螺钉系统应力分散,以尾侧椎弓根钉根部及钉棒连接处为著,从而减少椎弓根螺钉断钉的发生。AIM： To evaluate the stress of the spinal pedicle screw internal fixation system after adding laminal hOOKS. METHODS： The experiment was carried out in the Mechanics Experiment Center, College of Traffic and Communication, South China University of Technology on October 20, 2005.①Three-dimensional finite element analysis was applied to establish the model of the spinal pedicle screw system. The length of the pedicle screw and the rod was 40 mm and 120 mm respectively. The diameter of beth was 6 mm. The height of the laminal hook was 9 mm and length was 22 mm. ②The finite element model of pedicle screw system was established using ANSYS 8.0 software to restrain the caudal pedicle screw and the endosurfaca of caudal laminal hook, the loading was vertical to the cephalic pedicle screw.③Stress measurement： The stress change of spinal pedicle screw internal fixation system with or without laminal hOOks was explored under 5 N. m anteflexion torque. RESULTS： After adding hooks, the load-bearing points increased in number and became well-distributed. The stress on those points was significantly decreased, where was easily broken in clinic. The stress of axial direction was significantly decreased at the end of pedicle screws after hood added, especially in caudal pedicle screw where was decreased by 37.08%. The stress of shearing was significantly decreased in the conjunction of scraw-rod, the cephalic and caudal screws, which was decreased by 44.02% and 60.71% respectively. CONCLUSION： After novel hooks add, the stress of the pedicle screw system is well-distributed, significantly at the end of caudal screw and the conjunction of screw-rod. Thus the breakage of pedicle screws decreases.

关 键 词：椎弓根螺钉 椎板钩 有限元分析 

分 类 号：R318[医药卫生—生物医学工程]