Grading of epidural fibrosis in a new rabbit experimental model for epidural adhesive scar tissue formation

Abstract

This experimental study was planned to evaluate the success of rabbit hemilaminotomy procedure and proposing of a new grading system in the evaluation of epidural fibrosis. Fourteen New Zealand white rabbits were used in this experiment. Hemilaminotomy was performed in one level and 4 weeks later after operation rabbits were sacrificied. The lumbar spines were removed and immersed in 10% neutral buffered formalin for approximately 24 hours. Then each specimen was decalcified in 5% formic acid for approximately 3 weeks. Specimens were cut coronally for gross inspection. We proposed a new grading system in the evaluation of peridural fibrosis. In seven (50%) of the rabbits of hemilaminotomy sites, fibrous tissue penetrated into the spinal canal through the bone defect and produced neural compression with reaching to the posterior longitudinal ligament (Grade IV). Four hemilaminotomy sites were in Grade III fibrosis. Remaining 3 rabbits had Grade II fibrosis. In this experimental study, we modified the rabbit total laminectomy model by using of hemilaminotomy procedure in the studying of peridural scar formation. In the same time we proposed a new grading system in the evaluation of epidural scar tissue formation. © 2009 OMU All rights reserved.