Ligamentum flavum analysis in patients with lumbar discus hernia and lumbar spinal stenosis

The normal ligamentum flavum (LF) is a well-defined elastic structure with specific innervation. Several studies investigated LF in patients with lumbar spinal stenosis (LSS) and used lumbar discus hernia (LDH) patients as control group, only on the presumed thesis that LF in this patients have normal morphology. In patients with LSS thickening of the LF is the main cause of stenosis, which is most often presented with neurogenic claudication, whose pathophysiological mechanism is not completely understood. We conducted observational cohort study of 60 operated patients divided into two groups. The first group of 30 patients underwent micro-discectomy (LSH group), and second group with 30 patients underwent decompression, after which analysis of harvested LF was performed. Patients from the LDH group and LSS group differed significantly in the frequencies of chief complaints, duration of symptoms, physical examination, and specific morphological/radiological parameters. The LF analysis showed that the groups differed significantly in the amount of collagen and elastic fibers, as well as in the histological appearance/architectonics of elastic fibers. Also, groups differ in the presence of LF nerve fibers. Our findings speak in favor of the recently postulated inflammatory theory in the origin of spinal neurogenic claudication's.