Hypertrophied ligamentum flavum in lumbar spinal canal stenosis. Pathogenesis and morphologic and immunohistochemical observation
Yoshida, M.; Shima, K.; Taniguchi, Y.; Tamaki, T.; Tanaka, T.
Spine 17(11): 1353-1360
1992
ISSN/ISBN: 0362-2436 PMID: 1462211 Document Number: 395370
To investigate the pathogenesis of hypertrophy of the liagmentum flavum, 45 cases of lumbar canal stenosis were evaluated by computed tomography scan and pathologic and immunohistochemical studies. The ligamentum flavum along with the medial one-third of the superior facet was obtained en bloc to include the enthesis. Statistically significant differences in transverse area and thickness of the ligamentum flavum were evident compared to the control group (P lt 0.01). Pathogenesis of the hypertrophied ligamentum flavum was classified into three major groups: 1) fibrocartilage change due to the proliferation of type II collagen, 2) ossification and 3) calcium crystal deposition. It is stressed that marked proliferation of Type II collagen from the enthesis to the ligament side was revealed in the capsular portion of the hypertrophied ligament.