Object: Extensive peridural fibrosis after lumbar spine surgery may contribute to poor outcome and recurrent symptoms leading to repeated operation. Secondary procedures are considerably hampered by the presence of scar tissue. Moreover, after excision of the peridural scar, the fibrous tissue may recur, leading to unsuccessful surgical outcome. Mitomycin C (MMC), an alkylating antibiotic substance isolated from Streptomyces caespitosus, potentially suppresses fibroblast proliferation after surgical intervention. The authors investigated the effect of MMC on the reformation of epidural fibrosis in a laminectomy model in rats.
Methods: Twenty-four Wistar rats underwent a repeated lumbar laminectomy 3 months after the first operation. In 12 rats, MMC in a concentration of 1 mg/ml was locally applied to the laminectomy site. No treatment was performed in the control group of the other 12 rats. All rats underwent clinical evaluation. Mobility ratings and any evidence of neurological deficit were recorded. Twelve weeks after the second operation, the animals were killed for histological examination. The extent of epidural fibrosis and dural adherence was evaluated. All MMC-treated animals showed reduced epidural scarring, compared with the control group. In nine MMC-treated rats (75%), dural adhesions were moderate. In contrast, all control sites showed dense epidural fibrosis with marked dural adherence. No side effects of the treatment were observed.
Conclusions: In this experimental study, MMC in a concentration of 1 mg/ml locally applied significantly reduced recurrence of epidural fibrosis and dural adhesions without any side effects after repeated spinal surgery in a laminectomy model in rats.