Finite element analysis on adjacent segments for its biomechanical changes after artificial cervical disc prosthesis / 医用生物力学

ABSTRACT

ObjectiveTo study the range of movement (ROM) in adjacent vertebral segments and the changes in intervertebral disc stress after implanting artificial cervical disc. MethodA 3D finite element model for normal cervical spine was established using CT images scanned from a cadaver cervical spine. Simulation of bone graft and fusion of vertebral bodies as well as implantation of intervertebral disc prosthesis were performed between C5 and C6 . Then the ROM of adjacent functional spinal units (FSU, C4/5、C6/7) and the stress in C4/5 and C6/7 intervertabral disc were analyzed. Results（1）The model including the structures of ligaments, joint capsule and other soft tissue is built with high reality and accuracy；（2）Vertebral fusion increased movement range in adjacent FSU, and the stress in corresponding discs is significantly raised as well. The stress in nucleus pulposus and annulus fibrosus is increased about 70% at upper segment and 40% at lower segment; (3) After implantation of artificial disc, only the extension of cervicle spine is limited（P<0.05）; the stress in adjacent intervertebral disks is increased less than 10%. ConclusionsThe implanted artificial cervical disc can appropriately reduce the stress in adjacent vertebral segments, which is beneficial to improve the movement of the cervical spine.