Finite element analysis of cervical spine (C2-c7) with degenerated disc under normal loading and massage / 中国组织工程研究

ABSTRACT

BACKGROUND: Massage is a cost-effective treatment for cervical spondylosis. When the cervical vertebrae with different degenerative degree of intervertebral disc are massaged, the massage strength will have different effects because of the different degenerative degree, and improper manipulation of massage may also cause damage to the degenerative cervical vertebrae. At present, the related research is still lacking. OBJECTIVE: To investigate the mechanism of mechanical changes of cervical vertebrae with different degrees of disc degeneration under normal load and massage, and to explore the influence of massage rotation angle on different degrees of disc degeneration, so as to provide operational guidance for cervical vertebrae with different degrees of disc degeneration. METHODS: The finite element model of three-dimensional human cervical vertebrae (C2-C7) with high geometric similarity and accuracy and 2 million grids was established. The model with different degrees of cervical vertebrae degradation was obtained by changing the parameters of intervertebral disc. The finite element method was used to explore the mechanical mechanism of different degenerative degrees of intervertebral disc under the action of massage. RESULTS AND CONCLUSION: (1) After degeneration, the stress of intervertebral disc was redistributed; the bearing capacity of nucleus pulposus decreased; the bearing capacity of annulus fibrosus increased significantly; and the joint stress also increased. (2) Under normal load condition, the stress concentration area of the fiber ring was mainly located at the posterior side of the cervical spine. With the increase of degradation degree, the stress concentration region extended inward from the edge and the area increased. (3) The stress concentration area of fiber ring was mainly at the back and left and right sides with massage angle. The higher the degree of degradation, the greater the stress concentration area and the greater the stress value was. (4) When the massage was in rotation phase, the higher the degree of degeneration, the smaller the axial displacement and the smaller the deformation ability of the disc was. (5) C4-5 intervertebral disc degeneration will affect the maximum stress and joint contact force of the vertebral body (C4, C5) of the segment, and the stress value increases with the degree of degradation, but the degradation has no obvious effect on other segments. (6) Combined with the stress safety and deformation ability, the rotation angle should be reduced according to the degree of degradation.