Analysis and study on the factors of degenerative lumbar spondylolisthesis by multi-slice spiral CT / 中国医师进修杂志

Objective To explore the influencing factors of degenerative lumbar spondylolisthesis (DLS).Methods Sixty-one DLS patients (DLS group) were enrolled in this study.The control group was formed by 61 patients with same gender and age matched.The lesion position was L4 in two groups.The correlation of intervertebral joint angle,degeneration degree,lumbosacral angle and lumbar spondylolisthesis were analyzed.Results The intervertebral joint and sagittal angle in DLS group was less than that in control group[(37.11 ± 7.52)° vs.(42.44 ± 7.61)°] (P ＜ 0.01).The lumbosacral angle between two groups had no significant difference (P ＞ 0.05).The degeneration degree between two groups had significant difference (P ＜ 0.01).Conclusion Intervertebral joint and sagittal angle and intervertebral joint degeneration degree have important roles in DLS.

The Influence of Fixation Rigidity on Intervertebral Joints - An Experimental Comparison between a Rigid and a Flexible System

OBJECTIVE: Spinal instrumentation without fusion often fails due to biological failure of intervertebral joints (spontaneous fusion, degeneration, etc). The purpose of this study is to investigate the influence of fixation rigidity on viability of intervertebral joints. METHODS: Twenty pigs in growing period were subjected to posterior segmental fixation. Twelve were fixed with a rigid fixation system(RF) while eight were fixed with a flexible unconstrained implant(FF). At the time of the surgery, a scoliosis was created to monitor fixation adequacy. The pigs were subjected to periodic radiological examinations and 12pigs (six in RF, six in FF) were euthanized at 12-18months postoperatively for analysis. RESULTS: The initial scoliotic curve was reduced from 31+/-5degrees to 27+/-8degrees in RF group (p=0.37) and from 19+/-4degrees to 17+/-5degrees in FF group (p=0.21). Although severe disc degeneration and spontaneous fusion of facet joints were observed in RF group, disc heights of FF group were well maintained without major signs of degeneration. CONCLUSION: The viability of the intervertebral joints depends on motion spinal fixation. Systems allowing intervertebral micromotion may preserve the viability of intervertebral discs and the facet joint articular cartilages while maintaining a reasonably stable fixation.