高应力与腰椎小关节方向变化关系的实验研究

Experimental study on the orientation of lumbar facet joints induced by high stress in rabbits

中文关键词:  腰椎小关节  应力  退变  方向  兔

英文关键词:Lumbar facet joints  Stress  Degeneration  Orientation  Rabbit

中文摘要:

  【摘要】 目的：观察兔腰椎小关节加载应力后小关节方向的变化，并探讨小关节在应力作用下方向变化的机制。方法：将42只6月龄新西兰白兔随机分为正常对照组（A组）、椎间盘退变组（B组）、小关节加载组（C组）及椎间盘退变联合小关节加载组（D组），A组6只，其他3组各12只。对B组和D组动物采用针刺抽吸髓核法建立L3/4、L5/6椎间盘退变模型，对A组和C组仅剥离椎旁肌。建模6周后分别对C组和D组的L3/4、L5/6小关节加载拉簧造成高应力模型，对A组和B组仅行小关节暴露，分别于小关节术后4个月、8个月获取腰椎，进行MicroCT扫描，观察小关节形态，B、C、D组在横断面上测量L3/4、L5/6小关节角度（关节突关节面与椎体正中矢状面的夹角）并将两个节段数据合并分析，A组测量L3/4、L4/5、L5/6、L6/7小关节角度并将数据合并分析，小关节角度越小，小关节方向越偏向矢状位。结果：组内比较，各组8个月时小关节方向较4个月时更加矢状化（均P＜0.05）；同一时间点，D组的小关节方向较B组更加矢状化，C组的小关节方向较A组更加矢状化，差异均有显著性意义（均P＜0.05），A、B组间及C、D组间比较小关节角度无显著性差异（P＞0.05）。小关节加载组（C组和D组）的小关节较小关节未加载组（B组）退变严重，时间越长退变越严重；各时间点A组小关节结构清晰。结论：高应力可引起兔腰椎小关节退变，小关节方向的矢状化改变是由小关节退变和重塑所导致。

英文摘要:

  【Abstract】 Objectives: To investigate the orientation of lumbar facet joints induced by experimental stress in rabbits, and to explore the associated mechanism of these changes. Methods: Forty-two New Zealand white rabbits were randomly divided into 4 groups(A, B, C, D) which were assigned into different treatments. Group A received sham operation with intact lumbar spine structures. In group B, nucleus pulposus was aspirated to produce disc degeneration at L3/4 and L5/6. In group C, springs were put on the adjacent facets of L3/4 and L5/6 6 weeks later to stress the facet joints. Group D received the both treatments of group B and C. Lumbar spines were harvested after 4 months or 8 months respectively and then scanned by MicroCT. The morphology of facet joints was observed. Lumbar facet joint angles at level L3/4 and L5/6 were measured on the axial MicroCT images in group B, C, D, and the data were combined for analysis. The angles were measured at level L3/4, L4/5, L5/6 and L6/7 in group A, the data at 4 levels were combined. The angles measured were defined as midsagittal line through the disc and intersecting lines formed by connecting the two end points of each facet. The smaller the angle was, the more sagittally oriented the facet joint. Results: In each group, facet joints at the 8th month were more sagittally oriented than those at the 4th month(P＜0.05). Facet joint angles between group A and B or group C and D did not show significantly treatment-associated difference(P＞0.05). While facet joints in group D, which was loaded with additional stress on facet joints, were more sagittally oriented than those in group B(P＜0.05), and facet joints in group C were more sagittally oriented than those in group A(P＜0.05). Facet joints in group C and D, which sustained additional stress, presented with more degeneration than those in group B. Degeneration aggravated with time. While the structure of facet joints was clear in group A at two time points. Conclusions: High stress on facet joints induces lumbar facet joint degeneration in rabbits. A more sagittal orientation of facet joints is due to secondary remodeling of degenerative facet joints.