微创经椎间孔腰椎间融合术的有限元分析

目的：建立微创经椎间孔腰椎融合的有限元模型，通过比较不同固定方式的生物力学特性，来探讨最适宜的固定融合方式。方法分别建立以下融合固定模型：单枚融合器＋双侧椎弓根钉（A型）；双枚融合器＋双侧椎弓根钉（B型）；单枚融合器＋单侧椎弓根钉（C型）；双枚融合器＋单侧椎弓根钉（D型）。对各模型进行前屈、后伸、左屈、右屈、左旋、右旋、轴压加载，比较各模型的角位移、椎弓根钉及融合器的所受应力情况。结果各融合固定模型在不同工况下椎弓根钉及融合器所受应力的Von Mises峰值各有差异，但均在最大受力范围之内。各工况下四种模型角位移均较有限元模型减少，A/B型、C/D型相比角位移减少程度相当，而单侧椎弓根钉固定时脊柱稳定性较双侧椎弓根钉固定差。结论建立了不同固定方式的腰椎融合模型，验证了在微创经椎间孔腰椎融合术中使用单侧椎弓根螺钉加单枚融合器置入可提供适当的稳定，可以作为微创经椎间孔腰椎间融合术的固定方法选择。

Finite element analysis of transforaminal lumbar interbody fusion

Objective To develop and validate three-dimensional finite element models of transforaminal lumbar interbody fu-sion,and explore the most appropriate method of fixation and fusion by comparing biomechanical characteristics of fixation method . Methods Developing four fusion models：bilateral pedicle screws fixation with a single cage insertion model （ A）;bilateral pedicle screws fixation with two cages insertion model （ B）;unilateral pedicle screws fixation with a single cage insertion model （ C）;unilateral pedicle screws fixation with two cages insertion model （ D） ,the models were subjected to different forces including axial compressive ,an-terior bending ,posterior extension ,left bending and rotation .The von Mises stress of the fusion segments on the pedicle screw and cages were recorded .Results There were differences in Von Mises peak stress between four models ,but were within the range of maximum force.The angular variation in A ,B,C and D decreased significantly compared with normal .There was no significant differences in angu-lar variation between A and B ,C and D.Bilateral pedicle screws fixation had more superior biomechanics than unilateral pedicle screws fixation.Conclusion The lumbar interbody fusion models were established using varying fixation methods ,and the results verified that unilateral pedicle screws fixation with a single cage could meet the demand in transforaminal single segment interbody fusion .