背景:在颈椎病的致病因素中,椎间盘突出、小关节错位和椎间孔狭窄是导致患者出现症状的重要因素,而不适当的手法复位可能会加重颈椎间盘破裂的可能性,导致患者症状加重. 目的:通过有限元分析比较传统颈椎旋转复位手法与颈椎矢状位端提手法对施术节段椎间盘、小关节和椎间孔面积的影响. 方法:选取1名颈部正常男性志愿者的颈部CT资料,将CT数据导入Mimics 17.0三维重建软件,依次使用Geo-magic Studio 12.0、Solidworks 2017和Ansys Workbench 17.0软件构建椎间盘、关节软骨等C3-6颈椎有限元模型;固定C5椎体下终板,在上位椎体(C3)的上表面施加均匀分布、垂直向下的50 N载荷,比较实施传统颈椎旋转复位手法与颈椎矢状位端提手法和整复时,C4-C5节段椎间盘应力、形变大小及方向、关节囊应力、小关节位移及双侧椎间孔面积的变化. 结果与结论:①实施旋转复位手法时,C4-5椎间盘的最大范式等效应力为8.06 MPa、总形变为1.05 mm,纤维环向左前外膨出;实施矢状位端提手法时,C4-5椎间盘的最大范式等效应力为2.60 MPa、总形变为0.90 mm,纤维环向左后方膨出;相比于旋转复位手法,矢状位端提手法在施术时对椎间盘的压力较小(约为颈椎旋转手法的32.3%)、椎间盘形变程度也轻(约为旋转手法的85.7%);②实施旋转复位手法时,左侧和右侧关节囊韧带最大应力分别为0.37 MPa和1.69 MPa,小关节的总体位移为2.21 mm,右侧椎间孔面积减小约3.8%,左侧椎间孔面积增大约0.9%;实施矢状位端提手法时,左侧和右侧关节囊韧带最大应力分别为0.27 MPa和1.70 MPa,小关节的总体位移为1.63 mm,右侧椎间孔面积增大约2.6%,左侧椎间孔面积减小约0.9%;与旋转复位手法相比,矢状位端提手法对小关节的位移、关节囊应力和椎间孔面积改变较小,操作时较为安全;③结果提示,与颈椎旋转复位手法相比,矢状位端提手法对小关节位移、椎间盘应力/形变程度、关节囊应力和椎间孔面积的改变较小,临床中在准确评估患者病情后应结合生物力学结果选择更为合适的手法.
BACKGROUND:Among the pathogenic factors of cervical spondylosis,herniation of the intervertebral disc,dislocation of the facet joint and the stenosis of the intervertebral foramen are important factors leading to symptoms in patients.Moreover,inappropriate manipulation may aggravate the possibility of cervical disc rupture,leading to exacerbation of symptoms in patients. OBJECTIVE:To compare the effect between sagittal cervical manipulation and traditional cervical rotation manipulation on the area of the intervertebral disc,facet joint and intervertebral foramen at the operative segment by the finite element analysis. METHODS:The neck CT data of a male volunteer with a normal neck were selected and imported into Mimics 17.0 three-dimensional reconstruction software.Geo-magic Studio 12.0,Solidworks 2017 and Ansys Workbench 17.0 software were used for the construction of the finite element model of cervical vertebrae(C3-6)including intervertebral disc and articular cartilage.The lower end plate of the C5 vertebral body was fixed.A uniformly distributed vertical downward 50 N load was applied on the upper surface of the upper vertebral body(C3).The stress,deformation and deformation direction of the C4-5 intervertebral disc,joint capsule stress,the displacement of facet joints and the area of bilateral intervertebral foramen were compared between sagittal cervical manipulation and traditional rotation reduction. RESULTS AND CONCLUSION:(1)When using the rotation technique,the maximum normal equivalent stress(von Mises stress)of the C4-5 disc was 8.06 MPa;the total deformation was 1.05 mm,and the fiber ring expanded to the left and outside.When using the sagittal tip lifting technique,the maximum normal equivalent stress(von Mises stress)of the C4-5 disc was 2.60 MPa;the total deformation was 0.90 mm,and the fiber ring expanded to the left and back.Compared with the rotation technique,the pressure of the cervical manipulation technique on the disc was less(about 32.3%of the rotation technique),and the deformation degree of the disc was also light(about 85.7%of the rotation technique).(2)When the rotation technique was used,the maximum stresses of the left and right articular capsule ligaments were 0.37 MPa and 1.69 MPa,respectively.The overall displacement of the facet joint was 2.21 mm.The area of the right intervertebral foramen decreased by about 3.8%and the area of the left intervertebral foramen increased by about 0.9%.When the sagittal end lifting manipulation was performed,the maximum stresses of the left and right articular capsule ligaments were 0.27 MPa and 1.70 MPa,respectively;the overall displacement of the facet joint was 1.63 mm;the area of the right intervertebral foramen increased by about 2.6%,and the area of the left intervertebral foramen decreased by about 0.9%.Compared with rotation manipulation,sagittal end lifting manipulation had fewer changes in the displacement of facet joint,joint capsule stress and intervertebral foramen area,so it was safer to operate.(3)In conclusion,compared with cervical rotation manipulation,sagittal end lifting manipulation has fewer changes in facet joint displacement,intervertebral disc stress/deformation degree,joint capsule stress,and foraminal area.In clinical practice,more appropriate manipulation should be selected based on biomechanical results after an accurate assessment of patients'conditions.