颈前路零切迹椎间融合固定系统椎间融合术对邻近椎间盘生物力学影响的有限元分析

目的 探索颈前路零切迹椎间融合固定系统(Zero-P)椎间融合术对邻近椎间盘生物力学的影响,为颈椎病中远期疗效的评估提供参考.方法 采用正常成人颈椎薄层CT图像建立下颈椎(C4~C7)有限元模型,并验证其有效性,在此基础上建立单节段颈椎(C5/6)植入Zero-P系统后的有限元模型.分别加载前屈、后伸、侧弯、旋转等应力负荷,计算正常下颈椎及单节段颈椎(C5/6)植入Zero-P后相邻节段椎间盘的应力.结果 成功地建立了人体正常下颈椎、单节段(C5/6)植入Zero-P融合器后的下颈椎有限元模型.颈前路Zero-P椎间融合术后对邻近颈椎间盘应力较术前明显增大,以前屈及侧弯时更显著.结论 颈前路Zero-P椎间融合术可增加相邻椎间盘应力,术者需权衡利弊,充分考虑手术方式的影响,术后相应调整康复计划以减轻邻近节段负担.

Finite element analysis of effects of anterior cervical interbody fusion using Zero-profile device on biomechanics of adjacent cervical intervertebral disc

Objective To explore the effects of anterior cervical interbody fusion using Zero-profile device(Zero-P) on the biomechanics on adjacent cervical intervertebral disc,thereby to provide the reference for the evaluation of medium-and long-term efficacy on cervical spondylopathy.Methods A finite element model(FEM) of lower cervical spine(C4-C7) was established using thin-layer CT images of normal adult cervical spine,and then its validity was verified.On this basis,the FEM with Zero-P implanted into single segment of cervical spine(C5/6) was established.The stresses of adjacent cervical intervertebral discs were calculated in normal lower cervical spine and single segment of cervical spine(C5/6) after Zero-P implantation under different stress loads including flexion,extension,lateral bending and rotation.Results The FEMs of normal lower cervical spine and single segment of cervical spine(C5/6) after Zero-P implantation were successfully established.The stress of adjacent intervertebral disc increased obviously after anterior cervical interbody fusion with Zero-P,especially under flexion and lateral bending.Conclusion The stress of adjacent intervertebral discs increases after anterior cervical interbody fusion with Zero-P,thereby operators need to weigh the pros and cons and to fully consider the influence of surgical methods then adjust the corresponding rehabilitation plan to reduce the burden of adjacent segment.