抄録
This study is concerned with the mechanical causes of isthmic spondylolisthesis. The effects of disc degeneration on instability of isthmic defect vertebrae are discussed by using finite element analyses. The finite element model of disc is refined based on the model used in former study. Disc degeneration is modeled as a change of mechanical properties of annulus fibrosus. The results of flexion motion analyses show that the percentage of slipping is decreased by the change of mechanical properties of disc however the decrease of instability is not significant quantitatively. As slip angle is significantly increased, it may cause an initial damage of tissue in the disc.
