There is increasing evidence that topical application of
mitomycin-C can be beneficial in reducing epidural
scar adhesion. However, the ideal concentration of
mitomycin-C is unknown. The purpose of this study was to verify its efficacy for preventing epidural adhesion and the immediate electrophysiological responses caused by it in a
laminectomy model. Seventy rats underwent
laminectomy at L-1 and L-2. Cotton pads soaked with saline and various concentrations of
mitomycin-C (0.1 mg/ml, 0.3 mg/ml, 0.5 mg/ml and 0.7 mg/ml) were applied to the exposed dura for 5 min. Spine somatosensory evoked potentials (SSEP) were monitored in preoperative and the immediate electrophysiological responses of
mitomycin-C used. Four weeks postlaminectomy the rats were killed. The area of epidural
scar tissue and degree of epidural adhesion were determined by 7.0 T Micro MR imaging. Macroscopic evaluations were performed according to the Rydell standard. The results showed that severe epidural adhesion was formed in the saline group and no dural adherence or incomplete adhesions were found in the
mitomycin-C group. The Rydell classification and the degree of epidural adhesion and the area of the
scar in 0.5 mg/ml group and 0.7 mg/ml
mitomycin-C group revealed a significant decrease compared with the control group and 0.1 mg/ml group and 0.3 mg/ml
mitomycin-C group. The spine sensory evoked potentials did not alter obviously in both preoperative and the immediate electrophysiological responses of
mitomycin-C used. In conclusion, locally applied
mitomycin-C in a concentration of 0.5 mg/ml and 0.7 mg/ml
mitomycin-C may be the optimal concentration in preventing postlaminectomy epidural adhesion.