腰椎滑脱疲劳试验模型的研制与应用

Development and application of fatigue text model of isthmic spondylolisthsis

目的研制椎弓崩裂型腰椎滑脱疲劳实验模型,观察滑脱节段在脊柱内固定下不同方式椎体间植骨的生物力学变化。方法6具新鲜脊柱标本,截取L3～S2节段,制作腰椎滑脱试件。将试件随机分成2组,按临床方法安装复位固定系统(reduction fixation,RF),一组于椎间隙行双侧柱状植骨(bilateral-PLIF),另一组常规单侧植骨(single-PLIF)作为对照。在脊柱疲劳实验装置上进行生物力学测试。结果载荷500N时滑脱节段屈曲压缩位移变化显示,single-PLIF和bilateral-PLIF组疲劳前和初步疲劳(1500次)后都保持着良好的稳定性;10000次疲劳后双侧柱状植骨组在生物力学稳定性上明显优于对照组。结论本实验制作的腰椎滑脱疲劳实验模型适用于脊柱的生物力学测试;双侧柱状植骨有助于提高术后脊柱稳定性。

Objective To establish the fatigue text model of isthmic spondylolisthsis and observe the biomechanics stability of 2 kinds of posterior intervertebral fusion with spinal fixation.Methods Six specimens of lumbosacral cadaveric spine（L3-S2） were randomly divided into 2 groups and performed by implanting autograft iliac bones and spinal reduction fixation according to clinical operation,while one group underwent single posterior lumbar intervertebral fusion（single-PLIF） and the other group underwent bilateral posterior lumbar intervertebral fusion（bilateral-PLIF） as control.The specimens had biomechanical test on spinal fatigue testing machine.Results In the isthmic spondylolisthsis models,flexibility under loading 500 N showed that the stiffness of single-PLIF and bilateral-PLIF were good at initial and 1500 cycles.Bilateral-PLIF group had more biomechanics stability than single-PLIF group at 10000 cycles.Conclusion This fatigue text model of isthmic spondylolisthsis is fit for biomechanical study of spine.The stability of bilateral-PLIF is established immediately after operation.