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目的:探讨腰椎形态结构变化对峡部裂性滑脱及小关节退变的作用和意义。方法:采用改良的“非种子区域分割方法”及非平行“最佳切割平面”等一系列新型计算机辅助设计(CAD)方法精确建立包括椎间盘高度、腰椎小关节角、椎间盘前凸角改变的L4~L5活动节段有限元模型;在2700N轴向压缩载荷条件下,分别对各有限元模型的峡部、小关节应力、小关节接触力以及椎间盘负载进行测试。结果:压缩载荷下,腰椎活动节段峡部、小关节等效应力及小关节接触力随椎间盘高度的减小而减小,随小关节角的增大而增加,随椎间盘前凸角的增加而减小。结论:椎间盘高度、腰椎小关节角、椎间盘前凸角等形态结构变化对腰椎节段有限元模型的峡部、小关节应力及小关节接触力有明显的影响。提示腰椎峡部应力性骨折及小关节退变的发生与椎间盘高度、腰椎小关节角、椎间盘前凸角等解剖形态因素有关。
Objective: To investigate the effect and significance of lumbar spine structural changes on isthmic spondylolisthesis and degeneration of facet joints. Methods: A series of new computer-aided design (CAD) methods such as improved “non-seed region segmentation method” and non-parallel “optimal cutting plane” were used to accurately construct the L4 ~ L5 active segment finite element model; under the axial compressive load of 2700N, the isthmus, facet joint stress, facet joint contact force and intervertebral disc load of each finite element model were tested respectively. Results: Under compressive load, the equivalent force of the isthmus and facet joint and the contact force of facet joint decreased with the decrease of disc height, and increased with the increase of the angle of small joint. With the increase of disc lordosis angle Decrease CONCLUSION: The changes of disc height, facet joint angle and disc lordosis have significant effects on isthmus, facet joint stress and facet joint contact force of lumbar spine finite element model. Prompted lumbar isthmus stress fracture and facet joint degeneration and disc height, lumbar facet joint angle, lumbar disc angle and other anatomical factors.