腰椎单、双Cage置入加椎弓根钉内固定的三维有限元分析比较

3d-Finite Element Analysis of Single vs Double Fusion Cage Combined by Internal Pedicle Screw Fixation in Lumber Motional Model

目的:对腰椎单、双Cage置入加椎弓根钉内固定两种手术方法的生物力学进行比较,判断上述两种手术方法在生物力学上的优劣。方法:选取正常青壮年男性新鲜尸体的L4/5脊柱标本一具,进行横切扫描,利用三维重建软件M im ics建立椎弓根钉内固定有限元模型(模型1),单融合器置入加椎弓根螺钉内固定有限元模型(模型2)和双枚融合器植入加椎弓根螺钉内固定有限元模型(模型3);然后在模型上施加压缩、前屈、后伸载荷并测定在各种情况下螺钉和融合器上的应力,结果在excel软件上进行统计分析。结果:在所测的运动状态中,模型1的螺钉应力明显高于模型2和模型3(P<0.05),而模型2与模型3的螺钉应力的差异没有统计学意义(P>0.05);模型2的融合器压力高于模型3,其中在前屈及压缩状态下两者的差别有统计学意义(P<0.05),而后伸状态下差别无统计学意义(P>0.05)。结论:在所测的运动状态下,上述两种手术方法在生物力学上差异无显著性,应用椎弓根螺钉内固定加后路单枚椎间融合器斜行置入进行腰椎内固定融合的手术方法是可行的。

Objective：To compare the biological mechanics of two surgical approaches, single vs double fusion Cage combined by internal pedicle screw fixation in lumber model, providing the experimental evidences for clinical application. Methods： fresh normal male vertebra of L4-L5 specimen was used to construct the 3D pictures of model 1, model 2 and model 3 by continuous CT scan. The virtual sample was given different forces and measured for the stress of pedicle screw and fusion cage. All the measure data were sent into the computer and analyzed by the statistic software of Excel. Results ： In all movement states, stress of the screw in the model 1 was heavier than the model 2 and model 3 （ P 〈 0.05 ）, but stress of screw was not statistically different from model 2 with the model 3 （ P 〉 0.05 ） ; Stress of the fusion cage in the model 2 was heavier than the model 3, especially in the vertical compression and anterior bent states（P〈0.05）. Conclusions： In all movement states,there was no significant difference of biomechanics in two surgical models. The surgery with single cage combined by internal pedical screw is feasible.