Experimental Model of Intervertebral Disk Mediated Postoperative Epidural Fibrosis

Postoperative epidural fibrosis (EF) after lumbar discectomy is the most common and at the same time controversial issue.

The etiology and pathogenesis creates a lot of discussion and selection of methods of treatment and prevention continues.

LIV laminectomy with dura mater (DM) exposition was done in 24 rats, and then, 0.3 ml of elements of suspension of autologous intervertebral disk was implicated on DM. As autologous intervertebral disk, we used the intervertebral disk from amputated tail. In all the animals, incisions were closed with 3/0 Vicryl. EF was examined. Fibroblast cell density was calculated in each field at ×40 magnification: Grade 1 - fewer than 100 fibroblasts in each field; Grade 2 - 100-150 fibroblasts in each field; Grade 3 - more than 150 fibroblasts in each field.

Based on histological results, we confirmed our model of experiment. On the 30th day of evaluation, there were significant histological evidences of postoperative epidural adhesions in experimental animals, which included the obliteration of epidural space, the presence of adhesions in the dura and nerve roots, the restructuring of the yellow ligament, bone sclerosis, excessive appearance of fibrous tissue around the autologous intervertebral disk tissue that applied on the DM.

In our work, we describe a new experimental model, where the elements of autologous intervertebral disk play the role of inflammation trigger, which cause postoperative scar and EF.