Inhibition of epidural scar tissue formation after spinal surgery: External irradiation vs. spinal membrane application

Purpose: The scar tissue that forms after lumbar dissection is a severe com plication and a cause of lumbar and radicular pain. It was recently shown t hat radiotherapy could inhibit peridural fibrosis after laminectomy. In thi s study, the efficiency of external irradiation was compared with spinal me mbrane application. Method and Materials: Thirty male New Zealand rabbits underwent L5 laminect omy. Ten rabbits each received a single fraction of 900-cGy external irradi ation administered by 9-MeV electron beam 24 h after the surgery. Ten other rabbits each had spinal membrane applied during laminectomy. The remaining 10 rabbits constituted the control group. All of the rabbits were killed 3 0 days after the laminectomy. Axial histologic sections through the laminec tomy defect were evaluated. Each specimen was scored for the extent and den sity of fibrosis and arachnoidal adherence. Results: The extent and density of fibrosis and arachnoidal adherence diffe red significantly between the control group and the treatment groups (p < 0 .05). However, the extent and density of fibrosis and arachnoidal adherence did not differ significantly between the spinal membrane and irradiation g roups (p > 0.05). Conclusion: This preliminary study showed that high-single-fraction/low-tot al-dose administered postoperatively can successfully inhibit postsurgical epidural fibrosis as effectively as applied spinal membrane. (C) 2001 Elsev ier Science Inc.