Causes of unsatisfactory results of the use of mitomycin-C in endoscopic endonasal dacryocystorhinostomy

PURPOSE: To study the antifibrotic effectiveness of mitomycin-C in the tissues of the ostium site after it application for endonasal endoscopic dacryocystorhinostomy. MATERIAL AND METHODS: The study included 45 patients (48 cases) with primary obstruction of the nasolacrimal duct. All patients underwent endoscopic endonasal dacryocystorhinostomy (EEDCR). At the final stage of the operation, a swab with MMC was placed in the region of the formed ostium at a concentration of 0.2 mg/ml for 3 min. An ostium was not intubated. After that, biopsies of the mucous of the nasal cavity and lacrimal sac were performed to study the morphological changes that occur in the tissues overtime, as well as to calculate the concentration of the drug in the tissues. RESULTS: According to the chemical analysis, the concentration of MMC immediately after application was 0.626 ± 0.176 μg/g; after 30 min the concentration of the drug was reduced to 0.23 ± 0.06 μg/g; a day after the operation the drug was not found in the tissue samples. Morphological study established that the repair processes occurring in the mucosa of the nasal cavity and the lacrimal sac after EEDCR are similar to the reparative processes without the use of MMC. The effectiveness of surgical treatment: "positive results" - 77.1% of cases, "relapses" - 22.9% of cases. CONCLUSIONS: Application of MMC for prevention of excessive scarring after EEDCR is impractical as it is not possible to achieve antifibrotic concentration of the drug at dacryocystorhinostomy ostium site using this method.