LIGAMENTA-FLAVA IN LUMBAR DISC HERNIATION AND SPINAL STENOSIS - LIGHTAND ELECTRON-MICROSCOPIC MORPHOLOGY

Methods. Ligamenta flava obtained from nine patients with lumbar disc herniation and ten patients with lumbar stenosis were studied at histo logic, histochemical, and ultrastructural levels. Lumbar ligamenta fla va removed from six patients who underwent surgeries for thoracolumbar fractures were used as controls. Results. Ligamenta flava from contro l subjects consisted of large elastic fibers, thin bundles of collagen fibers, and few spindle-shaped fibroblasts. In proximity to the lamin al insertion, the ligaments had fibrocartilagineous features. In the c ontrol subjects who were age 50 or older, the cells decreased in numbe r and areas that had fewer and thinner elastic fibers and a more abund ant collagen component were visable occasionally. In patients with dis c herniation, the ligaments had similar morphologic features to those of the controls of similar ages. The ligamenta flava from patients wit h lumbar stenosis showed areas of fibrosis in which the cells were oft en represented by actively synthesizing fibroblasts and areas of chond roid metaplasia. Degenerating elastic fibers were seen occasionally, w hile calcified areas were observed often. Conclusions. Ligamenta flava undergo slight fibrotic and chondrometaplastic changes with aging. No peculiar changes occur in patients with disc herniation. In spinal st enosis, fibrotic changes, chondroid metaplasia, and calcification redu ce the elasticity of the ligaments, which may thus bulge into the spin al canal in the standing position even in they are normal in thickness .