旋转手法中侧屈方向对颈椎间盘位移、内在应力的影响及意义

Effect of lateral bending position on displacement and intra-stress of cervical disc with cervical rotatory manipulation in three-dimensional element analysis

目的利用三维有限元模拟颈椎分别在左、右侧屈位下行旋转手法,探讨该手法在不同方向侧屈体位下对颈椎间盘位移、内在应力的影响及意义。方法对一名25岁健康成年女性志愿者的颈椎进行CT扫描成像,应用Mimics10.01、Geomagic2012、Solidworks2014等软件建立C_(5/6)三维有限元模型,将模型导入Ansys Workbench14.5软件进行有效性验证及手法模拟。分别在颈椎左、右侧屈位下向右旋转,模拟实施旋转手法,将各项力学参数代入三维有限元模型进行计算分析,即时显示旋转手法作用时颈椎间盘的位移和内在应力变化。结果在左、右侧屈位下向右旋转,C_(5/6)三维有限元模型椎间盘左侧后部均出现向前回缩位移,左侧屈位(0.93 mm)小于右侧屈位(1.12 mm);椎间盘内在应力在左侧屈位时集中于旋转侧后部,右侧屈位时集中于旋转对侧后部,其中左侧屈位的最大应力(7.00 MPa)小于右侧屈位(8.19 MPa)。结论颈椎左侧屈位条件下向右旋转时对颈椎间盘位移、内在应力的影响均小于右侧屈位,更有利于保护同侧椎间盘;使用旋转手法治疗神经根型颈椎病时让患者向健侧旋颈时应向患侧侧屈,可在缓解症状的同时降低患侧椎间盘二次损伤的风险。

Objective To simulate the cervical rotatory manipulation（ CRM） in left/right lateral bending position by using the three-dimensional finite element,so as to investigate the effect of lateral bending position on the displacement and intra-stress of cervical disc when performing CRM. Methods With Mimics10. 01,Geomagic Studio,and Solidworks 14. 0 software,a three-dimensional finite element model of C5-6 was developed from the CT scan images of a 25-year-old normal adult female. The model was imported into Ansys Workbench 14. 5 to verify and simulate the CRM. The CRM was decomposed by principium of manipulation in left/right lateral flexion and rotated to the right side. The parameter of mechanics was analyzed with the finite element system. The change of displacement and intra-stress distribution in cervical disc simultaneously were displayed during simulating the manipulation. Results In left/right lateral bending position and rotated to the right side,the posterior part of the left side of cervical disc was all retracted. And the displacement was toward anterior,left lateral flexion（ 0. 93 mm） was smaller than the right lateral flexion（ 1. 12 mm）. The intra-stress of cervical disc were focused on the posterior part of the right side and the left side in left/right lateral flexion,respectively,and the maximum stress of left lateral bending（ 7. 00 MPa） was smaller than that of the right lateral bending（ 8. 19 MPa）.Conclusion When the cervical vertebra is in the left lateral bending position and rotates to the right side,the effects on the displacement and intra-stress are smaller than that of the right lateral bending position. Therefore,the left lateral bending position is more likely to protect the left side of cervical disc. When we treat cervical spondylotic radiculopathy with CRM,should let the patients rotate to the contralateral side with lateral flexion to the ipsilateral side. In this way,it can alleviate the symptom,and reduce the risk of secondary injury to the cervical disc of ipsilateral side at the same time.