NEOVASCULARIZATION IN HERNIATED LUMBAR DISC: A HISTOLOGICAL STUDY

Background: Inter-vertebral disc is the largest avascular structure in human body, which is primarily a load bearing and stabilizing unit of the human spine. Degenerative disorders and disc herniation causes proliferation or in growth of new blood vessels in this structure. Lumbar disc herniated tissues were studied microscopically in comparison with the cadaveric lumbar disc tissue, to evaluate the changes particularly the formation of new blood vessels. Methods: It was a case control study in which 45 lumbar herniated disc tissues (L4 – L5 and L5 – S1) and 45 dissected, fresh cadaveric disc tissues of same level and almost of same age groups were collected and in reference to age were divided into groups. Both sets of tissues were processed, sectioned and stained with Hemotoxyllin / Eosin, to observe the architecture of annuli fibrosis and nuclei pulposus parts of disc and the micro-vessels under light microscope. Results: Cadaveric discs, group A, B and C compared with herniated discs A1, B1 and C1, Annuli fibrosi in herniated discs (A1, B1, and C1) showed significant reduction of cells, disorganized lamellar pattern of collagen, formation of cysts, clefts and numerous new micro-vessels as compared to fresh cadaveric disc tissues (A, B and C). Conclusion: Disc degeneration and herniation results in the formation of micro-vessels which may not only serve as source of nutrients but also contribute in the healing process of discal tears.