不同单节段颈椎前路椎间融合系统对邻近节段的生物力学影响

目的 对比Zero-P零切迹颈椎前路椎间融合固定系统和Cage-Plate融合系统对相邻节段的生物力学影响，为单节段颈椎病的治疗远期临床疗效提供参考。方法 选择正常人CT扫描数据建立颈椎C1～7有限元模型，在验证模型的有效性后，分别建立在颈椎C5～6植入Zero-P和Cage-Plate融合系统的有限元模型。分别加载1.5 N·m扭矩模拟颈椎前屈、后伸、侧弯和旋转运动，对比正常情况下颈椎和分别植入Zero-P与Cage-Plate融合系统后相邻节段活动范围（range of motion, ROM）变化和椎间盘髓核、纤维环、终板及小关节上的应力。结果 两种颈椎融合器植入后，C4～5椎间ROM增大20%，但C6～7椎间ROM增大120%，C4～5、C6～7髓核上的应力分别增大78%、110%，相邻节段终板和纤维环上的应力均有所增大。结论 Cage-Plate和Zero-P融合系统植入后均会引起相邻节段ROM增大，以及相邻椎间盘髓核、纤维环和小关节上应力增大，长远上会引起邻近节段的病变。但Cage-Plate和Zero-P融合系统对邻近节段的生物力学影响没有本质区别。
Objective To compare biomechanical effects of Zero-Profile anterior cervical intervertebral fusion system and Cage-Plate fusion system on the adjacent segments, so as to provide references for the long-term clinical efficacy of single segment cervical spondylosis. Methods The finite element model of cervical spine C1-7 was established based on CT scan data of normal people. After the validity of the model was validated, two finite element models of C5-6 segment implanted with Zero-P fusion system and Cage-Plate fusion system were built. The physiological torque 1.5 N·m was loaded respectively on the normal model, Zero-P implanted model and Cage-Plate implanted model to simulate cervical flexion, extension, lateral bending and rotation. Changes in the ranges of motion (ROMs) of adjacent segments and stresses on nucleus pulposus, endplate and annulus, facet joints of intervertebral disc were compared for the three models. Results After the two kinds of anterior cervical intervertebral fusion systems were implanted, ROMs of C4-5 segments increased by 20%, but ROMs of C6-7 segments increased up to 120%. The stresses on C4-5 nucleus increased by 78%, while the stresses on C6-7 nucleus increased up to 110%. The stresses on the adjacent endplates and the fiber ring also increased. Conclusions The implantation of Cage-Plate and Zero-P fusion system both increased the ROMs of the adjacent segments, and the stresses on annulus, fiber rings and facet joints of the adjacent discs increased as well, which would cause lesions of the adjacent segments in the long run. However, there was no essential difference in biomechanical effects of the Cage-Plate and Zero-P cage fusion system on the adjacent segments.