The Reconstruction Of The Lumbar Spondylolisthesis Model And A Study Of Different Fusion Surgery Based On A Three-dimensional Finite Element Method

In shis study, we reconstructed the posterior approach fusion model of spondylolisthesis, such as the model of simple vertebral pedicle screw fixation system(model one), the simple double cages fixation system(model two), the fixation of vertebral pedicle screw plus post-lateral bone graft(model three), the vertebral pedicle screw plus double cages(model four), the vertebral pedicle screw plus single cages(model five), and so on. Then we studied thefive methods and compared their differences of the biomechanics.The results of this study as follow: First, the stability of interbody fusion is superior to either vertebral pedicle screw plus post-lateral bone graft or simple vertebral pedicle screw fixation. Second, no significant differences of screw stress and stability have been perceived, between the fixation of vertebral pedicle screw plus post-lateral bone graft and simple vertebral pedicle screw system, indicating that using a post-lateral graft-infusion method is not reliable in spondylolysis treatment. At last, whether using vertebral pedicle screw fixation either with double cage or monobloc cage, or merely using double cage method, segmental stability can be made. Combined with clinical experiences, monobloc cage causes less biomechanics changes and has fewer complications, and is cheaper as well. Thus, we consider it as the first choice in treating with patients with spondylolisthesis.