Neovascularization of nucleus pulposus - A diagnostic feature of intervertebral disc prolapse

Study Design. Seventy-five surgically excised prolapsed intervertebral disc s were histopathologically evaluated. Fifteen prospective normal cadaveric discs were used as control specimens. Objective. To compare the morphologic features between the prolapsed and no rmal discs. Summary of Background Data. The histologic criteria were edge neovasculariz ation of the fibrocartilage, chondrocyte cloning, fibrillation with fraying , and granular change. Methods. Sections stained with hematoxylin and eosin, Van Gieson's, and tol uidine blue were studied. The presence or absence of edge neovascularizatio n was noted. The other criteria were graded based on a semi-quantitative sc oring system. Results. Edge neovascularization was observed in 56% of the discs in the te st group and in none of the control specimens. Fibrillation with fraying wa s the most significant finding in the test group (P < 0.001). Although the mean grades were higher in the test group, they did not predict the presenc e of edge neovascularization. Conclusions. Edge neovascularization was the most significant finding to co nfirm disc prolapse. Fibrillation with fraying, was observed more frequentl y in prolapsed intervertebral discs and the grades of fibrillation with fra ying, chondrocyte cloning, and granular change were significantly higher in the test group. Pathologists can usually agree on the presence or absence of a particular histologic characteristic but are rarely consistent when th ey estimate the degree. Simple, reproducible agreed-on criteria are needed before semiquantitative evaluations become reliable.