目的：采用有限元分析方法研究镍钛记忆合金支架-骨粒-可吸收骨水泥式腰椎间融合术的生物力学性能。 方法：依次建立正常的L3-L5节段有限元模型（M0）、盒状融合器模拟植入的L4/5椎间融合术模型（M1）、镍钛记忆合金支架模拟植入的L4/5椎间融合术模型（M2）以及镍钛记忆合金支架模拟植入复合骨粒-可吸收骨水泥混凝物浇注植骨的L4/5椎间融合术模型（M3）。对模型进行力学加载，分析各模型生物力学稳定性和L4椎体下终板的峰值应力。 结果：M1、M2模型L4/5节段在前屈、后伸、侧屈、轴向旋转方向上的活动度较M0明显降低。在M3中， 手术节段稳定性进一步提高，且L4下终板峰值应力远小于M1、M2。 结论：镍钛记忆合金支架与传统盒状融合器在单独用于腰椎间融合术时具有生物力学等效性，在复合应用骨粒-可吸收骨水泥混凝物浇注植骨后能进一步提升稳定性及降低终板应力。
Purpose: The objective of this study is to evaluate the postoperative biomechanics of NiTi memory alloy frame with absorbable bone cement/autogenous bone granule casting for lumbar interbody fusion. Methods: Validated model of normal L3-L5 segment finite element model (M0) , L4-5 intervertebral fusion model with box cage (M1), L4-5 intervertebral fusion model with NiTi memory alloy frame (M2) and L4-5 interbody fusion model with absorbable bone cement/autogenous bone granule casting (M3) were constructed. Under mechanical loading, the biomechanical stability of each model and the peak stress of L4 interior endplate were analyzed. Results: The range of motion of L4-5 segment in M1 and M2 models was significantly lower than that of M0 in flexion, extension, lateral flexion and axial rotation. In M3, the stability of the segment was further improved and the range of motion was even reduced by 96%. The stress distribution of M3 is relatively dispersed, and the peak stress is less than M1 and M2. Conclusion: NiTi memory alloy frame and traditional box fusion cage have biomechanical equivalence when used alone in lumbar interbody fusion. And application of concrete casting bone graft can further improve the stability and reduce the stress of endplate.