Evaluation of DuraGen in preventing peridural fibrosis in rabbits

Abstract

Object Peridural fibrosis is the scar tissue formed over the dura mater after a laminectomy. It has been implicated as a cause of persistence of pain after spinal surgery and associated with increased risk of complications during revision surgery. The application of a mechanical barrier to cover the peridural space to block the migration of inflammatory cells from superficial layers to the epidural space can potentially prevent or decrease scar formation. The authors evaluated the use of DuraGen for this purpose. Methods Seventeen New Zealand White rabbits underwent bilateral L-4 and L-7 laminectomies. Each space was randomly assigned to either receive DuraGen, fat graft, or no (sham) treatment. At a mean 18 ± 4 weeks after surgery, the animals underwent magnetic resonance (MR) imaging with and without Gd enhancement, and the area of the scar tissue overlying the middle of the laminectomy was measured. The rabbits were killed and the spinal cords with an intact dural covering were harvested. The midsection of each treated level was evaluated histologically and the scar area was measured. In rabbits in which a fat graft was placed, MR imaging of the epidural space demonstrated a significant (p < 0.05) increase in the mean area (0.9713 mm2) of scar tissue compared with those in which DuraGen was used (0.687 mm2) or those receiving sham treatment (0.6661 mm2). The same correlation was observed when the histological sections were measured at the middle of the laminectomy site where the mean areas of both DuraGen (1008 mm2) and control (2249 mm2) groups were significantly lower than that in the fat graft group (6007 mm2) (p < 0.01 and 0.05, respectively). No significant differences between the DuraGen and control groups were observed. Conclusions The authors demonstrated that peridural scarring formed in all groups. The mean area of scar deposition was significantly higher in the fat graft group than in the DuraGen or control group both on MR imaging and histological analysis. DuraGen was more effective than a fat graft in preventing epidural fibrosis but not significantly different from that occurring in control animals.