TLIF术中最优化单侧螺钉植入和融合器放置的有限元分析

发布时间：2018-08-09 13:36

【摘要】：目的比较经单侧腰椎间孔椎体间融合(transforaminal lumbar interbody fusion,TLIF)中不同轴向植入角度椎弓根螺钉和不同放置位置融合器的生物力学特性。方法建立正常L3~5有限元模型,在验证其有效性基础上,在L4~5节段模拟后路双侧TLIF和4种不同组合类型椎弓根螺钉植入和融合器放置的单侧TLIF有限元重构模型,即:小角度植入椎弓根螺钉+对侧放置融合器(模型A)、小角度植入椎弓根螺钉+同侧放置融合器(模型B)、大角度植入椎弓根螺钉+同侧放置融合器(模型C)、大角度植入椎弓根螺钉+对侧放置融合器(模型D),分别比较4种重构模型在各种生理应力下的活动范围(range of the motion,ROM)以及螺钉、融合器与L4下终板界面的最大Von Mises应力差异。结果 4种单侧TLIF重构模型在融合节段(L4~5)ROM均较正常模型显著下降,但仍高于双侧TLIF重构模型。4种单侧TLIF重构模型稳定性比较,模型C下降最多,其在屈伸、侧屈和扭转应力下ROM分别减少约为正常模型的50.7%、89.9%和90.3%。螺钉和融合器与L4下终板界面最大Von Mises应力比较,相对于其他3组模型,模型C除了在同侧侧屈和扭转外的大部分应力下承受较小的应力。结论在单侧TLIF重构模型中选择大角度植入椎弓根螺钉和同侧放置融合器能够获得最佳的生物力学稳定性,通过缩小与双侧TLIF模型稳定性差异以减少断钉或融合器下沉的风险,值得临床推广运用。
[Abstract]:Objective to compare the biomechanical characteristics of pedicle screw and fusion cage with different axial angle in transunilateral intervertebral foramen fusion (transforaminal lumbar interbody). Methods A normal L3 / 5 finite element model was established. Based on the validity of the model, the posterior bilateral TLIF and the unilateral TLIF finite element reconstruction model of pedicle screw implantation and fusion cage placement were simulated in L4 5 segment. That is: small angle pedicle screw placement cage (model A), small angle pedicle screw implantation ipsilateral fusion cage (model B), large angle implant pedicle screw ipsilateral fusion cage (model C), large angle) Transpedicle screw transpedicular cage (model D),) was used to compare the (range of the motionless ROM of four reconstructed models under various physiological stresses, as well as screws. The maximum Von Mises stress difference between the interface of the fusion cage and the lower end plate of L 4. Results the ROM of the four unilateral TLIF reconstruction models decreased significantly compared with the normal model, but still higher than that of the bilateral TLIF remodeling model. The stability of the four unilateral TLIF remodeling models was significantly lower than that of the bilateral TLIF remodeling model. The stability of the four unilateral TLIF remodeling models was significantly lower than that of the normal model. ROM was reduced to 50.789% and 90.3% of the normal model under lateral bending and torsional stress, respectively. Comparing the maximum Von Mises stress at the interface of screw and fusion cage with that of L4 lower end plate, compared with the other three groups of models, model C bears relatively small stress except for the majority of stresses in the ipsilateral bending and torsion. Conclusion the best biomechanical stability can be obtained by selecting large angle pedicle screw implantation and ipsilateral fusion cage in unilateral TLIF remodeling model, and the risk of breaking or sinking can be reduced by reducing the difference between the stability of TLIF model and that of bilateral TLIF model. It is worth popularizing in clinic.
【作者单位】：浙江省立同德医院骨伤科;广州中医药大学第一附属医院脊柱骨科;
【基金】：浙江省自然科学基金项目(LY13H060011)
【分类号】：R318.01;R687

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