人工颈椎间盘置换术对邻近节段生物力学影响的三维有限元分析

Biomechanical effects of placement of a disc prosthesis and adjacent vertebral bodies

[目的]建立人工颈椎间盘置换术前、术后(C4～7)的三维有限元模型,分析颈椎间盘置换术的特点,并探讨术后对邻近节段生物力学的影响。[方法]选取1名行人工颈椎间盘置换的男性病人的术前、术后CT片,范围为C4～7,(包括椎体、邻近椎体和邻近椎间盘)分别建立术前、术后的三维脊柱功能单元的有限元模型。对模型加载2N.m的力矩和10N.m的转矩,分析其在垂直载荷、前屈、后伸、侧屈及旋转的情况下,手术前后的椎体的变化以及椎体皮质骨、松质骨、椎间盘、终板的应力改变,以及活动度的变化。[结果]手术后轴向负荷力线后移,人工间盘邻近椎体上下终板所受应力,以及邻近椎间盘所受应力有所增加,但所受压力、张力不明显。节段活动度的变化减小不明显。[结论]人工颈椎间盘置换术有效的改善了脊柱功能单位的生物力学性能,但需谨慎选择人工椎间盘的大小,并且最大限度保留终板骨性组织,以避免出现术后假体下沉、移位、脱出、节段后凸等不良影响。

[Objective]To present a validated two-functional spinal unit C4~7 finite element model with simulated placement of a disc prosthesis treatment to predict stresses and strains within adjacent vertebal bodies. [Methods]Two finite element models of C4~7 were generated using the CT scans taken from a male patient following placement of a disc prosthesis treatment,which were included with adjacent bodies,intervertebral discs. Simulations were conducted imposing a compression preload combined to a flexion/extension moment,a pure lateral bending moment and a pure torsion moment,and to quantify the stress levels in intervertebral discs,endplate,cancellous bone,cortical bone and adjacent bodies following placement of a disc prosthesis under clinically relevant loading conditions.[Results]The BryanTM disc prosthesis allows to correctly reproduce a physiological motion at the implanted level,and the changes in stresses and strains in levels adjacent to a placement of a disc prosthesis treatment level were minimal.[Conclusion]The artificial cervical disc prosthesis well restores the biomechanical behavior of the intact spine. Moreover,the selection of surgical indications and proper manipulations shoule bve paid more attehtion to.