Effects of intraoperative sponge mitomycin C and 5-fluorouracil on scar formation following strabismus surgery in rabbits

PURPOSE: To investigate the influence of 5-fluorouracil (5-FU) and mitomycin C (MMC) on the postoperative adhesions following strabismus surgery in rabbits. METHODS: Twenty-one New Zealand white rabbits were used in this prospective, masked, controlled trial. Both eyes of 20 animals underwent 3-mm recession of the superior rectus muscle (SRM). In group I (io animals), one eye of each animal received topical application of MMC (0.2 mg/ml) for 5 minutes and the other eye (control eye) was treated with balanced salt solution (BSS) using an intraoperative sponge. In group II (10 animals), a randomly chosen eye of each animal was treated with 5-FU soaked sponges (50 mg/ml) for 5 minutes and the fellow eye (control eye) with BSS. Two eyes of a rabbit were included as unoperated controls. Four weeks after the surgery, conjunctival vascularity and postoperative adhesions between the SRM Tenon's capsule (TC) and SRM sclera (scl) were assessed. Additionally, eyes were enucleated and evaluated histopathologically for evidence of scarring, granuloma formation, and muscle tissue changes under a light microscope. RESULTS: MMC-treated eyes had a higher rate of avascular conjunctiva compared to both controls and 5-FU-treated eyes. Mean adhesion scores, particularly between the SRM-scl, were lower in eyes treated with antiproliferative agents compared to controls. The difference was statistically significant in MMC-treated eyes for the adhesions between SRM-scl (p = 0.03). Histopathological examination revealed less scarring and granuloma formation in MMC- and 5-FU-treated eyes compared to their control eyes. CONCLUSIONS: MMC, and to a lesser extent 5-FU, are shown to be effective in reducing postoperative scarring following strabismus surgery in rabbits. It seems reasonable to suggest that antimetabolites should be used for cases having an increased risk of postoperative adhesions.