Experimental rabbit hemilaminotomy model in the evaluation of peridural fibrosis: a minimally invasive peridural fibrosis model.

The neuronal adhesions of newly synthesized scar tissue to dura mater after spinal peridural operations represent an unsolved problem in neurosurgical practice. This experimental study was planned to compare the success of a rabbit hemilaminotomy procedure with the total laminectomy model in the evaluation of peridural fibrosis in terms of proposing a lesser invasive peridural adhesion model. Fourteen New Zealand white rabbits were used in this experiment. Laminectomy was performed in one level, and hemilaminotomy was done in another level. Four weeks after operation the rabbits were sacrificed by perfusion with 10 % neutral buffered formalin solution. 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. Two blocks of tissue were taken from each laminectomy site to be processed and embedded in paraffin. In seven (50 %) of the laminectomy sites of the rabbits, fibrous tissue penetrated the spinal canal through the laminectomy defect and produced neural compression (Grade III). Eight (57 %) hemilaminotomy sites were in Grade III fibrosis. There was no difference between laminectomy and hemilaminotomy in regard to the dural adhesions. In this experimental study, we modified the rabbit total laminectomy model by using a hemilaminotomy procedure in the study of peridural scar formation. The authors conclude that this procedure is more simple, reliable, and lesser invasive than the total laminectomy model.