TLIF单双侧椎弓根螺钉固定融合前后的有限元分析

目的 探索经椎间孔腰椎椎间融合术(TLIF)单双侧椎弓根螺钉固定方式在椎间植骨融合前后存在的差异.方法 基于正常人L3~5节段的CT扫描数据建立人正常L3~5三维有限元模型(INT )和 TLIF手术模型 ,并在此基础上构建椎间融合前单侧和双侧椎弓根螺钉固定模型(M1和M2) ,以及椎间融合后单侧和双侧椎弓根螺钉固定模型(M3和M4).在设定的加载和边界条件下 ,模拟腰椎前屈、后伸、侧屈及旋转运动 ,并记录L4~5节段角位移和内植物应力分布情况.结果 单侧和双侧椎弓根螺钉固定模型在融合前均较完整状态减少了节段的活动度 ,双侧固定减少幅度更大 ,而融合后这种差异明显缩小.融合前单侧固定的钉棒系统Von Mises应力峰值明显高于双侧固定 ,而融合之后二者应力峰值趋于一致.结论 融合后单侧固定可以提供和双侧固定一致的节段稳定性 ,T L IF手术应用单侧椎弓根螺钉固定的远期临床效果与双侧固定相似.

Finite element analysis of unilateral and bilateral pedicle screw fixation before and after segment fusion in transforaminal lumbar interbody fusion

Objective To explore the difference between before and afteintervertebral fusion in transforaminal lumbainter-body fusion (TLIF) by unilateral obilateral pedicle screw (PS) fixation .MethodThe L3 -5 Cdatbased on the normal people were used to rebuild the L3 -5 three-dimensional finite elemenmodel(INT) and TLIF operative model .On thibasi,the unilateral Pfixation (M1) and bilateral Pfixation (M2) modelbefore the intervertebral fusion and the unilateral Pfixation (M3) and bi-lateral Pfixation (M4) modelafteintervertebral fusion were buil.Aftesetting the boundary and loading the burden ,the ante-flexion ,retroversion ,lateral bending and rotation of lumbavertebrwere simulated and the L 4 -5 segmenanguladisplacemenand the stresdistribution of implanwere recorded .ResultThe unilateral and bilateral Pfixation model before fusion reduced the range of motion(ROM ) of segmencompared with the Inmodel ,the bilateral fixation wareduced greatethan the unilateral fixa-tion ,buthe difference aftefusion wasignificantly decreased .The peak Von Misestressebefore fusion in the unilateral Pfixa-tion wasignificantly highethan thain the bilateral fixation ,while theipeak Von Misestresseaftefusion trended to be con-sisten.Conclusion The unilateral Pfixation aftefusion can provide the consistensegmenstability same to the bilateral Pfixa-tion .The long-term effecof TLIF with unilateral Pfixation isimilato thawith the bilateral Pfixation .