下腰椎关节突关节骨性关节炎程度与黄韧带厚度和骶骨倾斜角的关系

The relationships between the degree of facet joint osteoarthritis at lower lumbar spine and ligamentum flavum thickness as well as the sacral inclination

目的：探讨下腰椎关节突关节骨性关节炎（facet joint osteoarthritis，FJOA）程度与黄韧带厚度和骶骨倾斜角的关系。方法：在90例60—80岁腰腿痛患者的CT轴位骨窗像上评定L3／4、L4，5、L5／S1水平两侧的HOA等级，共分为I、Ⅱ、Ⅲ、Ⅳ级．再分为FJOAI-Ⅱ级和FJOA III—IV级两组；在CT轴位软组织窗像上测量和比较两组黄韧带的厚度（黄韧带中点处的厚度）。回顾同一关节水平两侧HOA等级对称以及不对称的影像资料，分别对两侧相应的黄韧带厚度进行比较。在二维重建矢状位CT像上测量骶骨倾斜角并按其大小分为两组．比较骶骨倾斜角大小不同组的黄韧带厚度及HOAⅢ-IV级构成比。结果：L3／4、L4／5、L5／S1的HOAI-Ⅱ级构成比分别为60．5％、56．1％、68．9％，HOA III—IV级构成比分别为39．5％、43．9％、31．1％。在HOAI-Ⅱ级组中，L3／4、L4／5、L5／S1水平的黄韧带厚度平均分别为3．52mm、3．77mm、3．22mm；在FJOA III-IV级组中，L3／4、L4／5、L5届1水平的黄韧带厚度平均分别为3．72mm、4．01mm、3．89mm；各水平两组比较均有显著性差异（P〈0．05）。在两侧HOA等级对称者中，各水平两侧黄韧带厚度均无显著性差异（P〉0．05）。在两侧HOA等级不对称者中，各水平HOAⅢ-IV级侧的黄韧带均较FJOAI-Ⅱ级侧显著增厚（P〈0．05）。骶骨倾斜角平均为33．2°，〈33．2°组L4／5、L5／S1水平的黄韧带与≥33．2。组比较显著增厚（P〈0．05），在L3／4水平两组无显著性差异（P〉0．05）。骶骨倾斜角〈33．2°组各水平FJOAⅢ-IV级构成比与≥33．2°组比较无显著性差异（P〉0．05）。结论：下腰椎两侧关节突关节存在骨性关节炎程度不对称的现象。下腰椎HOA的加重与黄韧带增厚有关，与骶骨倾斜角的减小无关。

Objectives：To investigate the relationships between the degree of facet joint osteoarthritis （FJOA） at lower lumbar spine and ligamentum flavum（LF） thickness as well as the sacral inclination. Methods： The grade of bilateral FJOA from 90 patients aged 60-80 years and suffering from low back pain and sciatica was evaluated at L3/4, L4/5 and L5/S1 levels on axial CT scan, and all cases were divided into two groups as grade I- II （group I） and grade III-IV（group 2）. The thicknesss of LF in two groups were measured at their median part and compared statistically. By reviewing the image data of symmetric or asymmetric FJOA at the same level, the thickness of LF on one side was compared statistically with the contralateral side at each level. Sacral inclination angle was measured on sagittal two-dimensional CT images and divided into two groups. The thicknesss of LF and component percentage of FJOA III-IV were compared between two groups at different sacral inclination respectively. Results： At L3/4, L4/5and L5/S1 levels, the FJOA I- II accounted for 60.5%, 56.1% and 68.9% respectively, while the FJOA III-IV accounted for 39.5%, 43.9% and 31.1% respectively. In group 1, the mean thickness of LF was 3.52mm, 3.77mm, and 3.22mm for L3/4, L4/5 and L5/S1 respectively; while in group 2, the mean thickness of LF was 3.72mm, 4.01mm and 3.89mm for L3/4, L4/5 and L5/S1 respectively, which showed significant difference between the two groups at each level （P〈 0.05）. In patients with symmetric FJOA on both sides, there was no significant side-related difference as for the LF thickness at each level（P〉0.05）. In patients with asymmetric FJOA on both sides, the side of FJOA III -IV showed greater LF thickness compared with the other side of FJOA I- II at all three levels （P〈0.05）. The mean sacral inclination angle was 33.2°. The group with sacral inclination angle 〈33.2° had significantly thicker LF than group with sacral inclination angle ≥33.2° at L4/5 and L5/S1（P〈0.05）, but had no significant difference compared with L3/4 level（P〉0.05）. The rate of FJOA III-IV in group with sacral inclination angle 〈 33.2° at each level showed no difference with sacral inclination angle ≥33.2°（P〉0.05）. Conclusions： Asymmetric FJOA on both sides is present in lower lumbar spine. The severity of FJOA at lower lumbar spine is associated with LF thickening rather than decrease of sacral inclination angle.