Tribology Research Institute, School of Mechanical Engineering, Southwest Jiaotong University, No. 111, North 1st Section of Second Ring Road, Chengdu 610000, China.
Department of Orthopedics, West China Hospital, Sichuan University, No.37, Guoxue Xiang, Chengdu 610000, China.
Med Eng Phys. 2022 Apr;102:103779. doi: 10.1016/j.medengphy.2022.103779. Epub 2022 Feb 19.
Clinic observations have shown that facet tropism with respect to the sagittal plane is associated with cervical degeneration, but their mechanisms haven't been clearly revealed. This study developed different levels of facet tropism musculoskeletal multi-body dynamics cervical models to investigate the biomechanical effect on the intervertebral compressive force (ICF), intervertebral shear force (ISF), facet joint force (FJF) and intervertebral disc displacement (IDD) during head flexion, extension, lateral bending and axial rotation movements. Results showed that the ICFs at the asymmetrical levels of the severe facet tropism models increased by 9.33% and 15.34% respectively during extension and right lateral bending, but did not change significantly during axial rotation. The ISFs at the asymmetrical levels of the severe facet tropism models increased by 56.64% and 164.40% respectively during right lateral bending and right axial rotation. The corresponding IDDs in medial-lateral direction at asymmetrical level also increased greatly during extension, right lateral bending and right axial rotation. The FJFs at asymmetrical level of the severe facet tropism models decreased by 3.41%, 10.55% and 9.19% during extension, right lateral bending and left axial rotation, but increased by 22.62% during right axial rotation. Facet tropism increased the ICFs, ISFs and IDDs of the asymmetrical level, but reduced the protection against cervical excessive motion during certain head movements. The results suggested that facet tropism may contribute to the initiation or enhancement of the process of intervertebral disc degeneration, especially intervertebral disc herniation.
临床观察表明，矢状面对小关节面的倾斜与颈椎退变有关，但它们的机制尚未明确揭示。本研究建立了不同程度的小关节面倾斜的颈脊柱多刚体动力学模型，以研究在头前屈、后伸、侧屈和旋转运动时，对椎间压（ICF）、椎间剪切力（ISF）、小关节面力（FJF）和椎间盘位移（IDD）的生物力学影响。结果表明，在严重小关节面倾斜模型的不对称水平上，伸展和右侧侧屈时 ICF 分别增加了 9.33%和 15.34%，但在旋转时没有明显变化。在严重小关节面倾斜模型的不对称水平上，右侧侧屈和右侧轴向旋转时 ISF 分别增加了 56.64%和 164.40%。在伸展、右侧侧屈和右侧轴向旋转时，不对称水平的相应椎间向内侧-外侧方向的位移也大大增加。在严重小关节面倾斜模型的不对称水平上，伸展、右侧侧屈和左侧轴向旋转时 FJF 分别减少了 3.41%、10.55%和 9.19%，但在右侧轴向旋转时增加了 22.62%。小关节面倾斜增加了不对称水平的 ICFs、ISFs 和 IDDs，但在某些头部运动时降低了对颈椎过度运动的保护作用。结果表明，小关节面倾斜可能有助于椎间盘退变过程的启动或加剧，特别是椎间盘突出。
