有限元法分析多节段颈椎病4种颈前路修复方式的生物力学特点

Biomechanics characteristics of four anterior cervical reconstructive techniques in the surgical management of multilevel cervical spondylotic myelopathy: a finite element model study

背景:多节段颈椎病因脊髓多严重受压,故多需手术去除压迫,但是对于选择何种前路修复方法最好,目前仍未达成共识。目的:利用三维有限元模型对4种颈椎前路修复方式进行对比分析,分析其生物力学特点。方法:基于健康成年男性C2-C7节段CT图像建立颈椎有限元模型。模拟4种颈椎前路修复方式分别建模,包括颈椎前路椎间盘切除融合、颈椎前路椎体次全切除融合、颈椎前路混合减压融合、颈椎前路间盘切除减压单纯Cage置入融合,计算C盘以及钛板-螺钉界面应力变化情况。2/3、C6/7椎间结果与结论:(1)4种颈椎前路修复方式在前屈、后伸、侧屈、旋转工况下相邻节段的椎间盘应力均为C2/3节段大于C6/7节段,而且均是颈椎前路间盘切除减压单纯Cage置入融合组椎间盘应力最小,颈椎前路椎体次全切除融合组椎间盘应力最大;(2)钛板-螺钉界面应力颈椎前路椎体次全切除融合组最大,颈椎前路椎间盘切除融合组最小;(3)结果说明,在修复多节段颈椎病的4种颈前路融合内固定方式中,颈椎前路间盘切除减压单纯Cage置入融合对于相邻节段的生物力学影响最小,理论上可以降低邻近节段退变的发病率,但该方法存在增加融合器沉降的风险。

BACKGROUND：Surgical treatment is commonly used for decompressing the spinal cord in multilevel cervical spondylotic myelopathy, but the optimum anterior cervical reconstructive method has not been determined. OBJECTIVE：To compare and analyze the biomechanical characteristics of four anterior cervical reconstructive techniques in the surgical management of multilevel cervical spondylotic myelopathy utilizing the three-dimensional finite element model. METHODS：A three-dimensional finite element model of an intact C2–7 segment was developed and validated based on healthy adult male CT images. Four additional models were developed from the fusion model, including anterior cervical discectomy and fusion, anterior cervical corpectomy and fusion, anterior cervical hybrid decompression and fusion and anterior cervical discectomy and fusion with Cage alone. Von Mises stresses on the plate and the disc of adjacent levels （C2/3, C6/7） were comparatively analyzed. RESULTS AND CONCLUSION：（1） The C2/3 disc stress in flexion, extension, lateral bending and rotation condition was significantly higher than the C6/7 disc in 4 anterior cervical reconstructive techniques, and the adjacent disc stress （C2/3, C6/7） was lowest in the anterior cervical discectomy and fusion with Cage alone, and highest in the anterior cervical corpectomy and fusion. （2） The stress at the plate-screw interface was highest in the anterior cervical corpectomy and fusion, and lowest in the anterior cervical discectomy and fusion. （3） In conclusion, among the four anterior cervical reconstructive techniques for multilevel cervical spondylotic myelopathy, the anterior cervical discectomy and fusion with Cage alone makes little effect on the adjacent disc stress, which might reduce the incidence of adjacent segment disease after fusion. However, the accompanying risk of the increased incidence of cage subsidence should never be neglected.