Mitomycin C: Techniques and Tissue Effects

Abstract

Cicatricial closure of the dacryocystorhinostomy ostium is one of the frequent causes of surgical failure [1]. Mitomycin C (MMC) has been used in dacryocystorhinostomy to modulate aggressive wound healing and prevent cicatricial closure of the DCR ostium [2, 3]. Several basic science studies have provided evidence of its effects on nasal mucosal fibroblasts [4–7]. Clinical application is either in the form of an intraoperative topical application or injectable in the circumostial (COS) areas, a technique described as COS-MMC. The utility of COS-MMC has been demonstrated in short- and long-term outcomes [3, 8]. The therapeutic range of MMC in DCR surgery was found to be 0.02 mg% for 3 min to 0.04 mg% and <5 min [4]. Ultrastructural effects of topical MMC (0.02 mg%, 3 min) and COS-MMC (0.2 mg/ml) on nasal mucosa have been evaluated and compared with the untreated naïve nasal mucosa (as controls) [7]. Detailed transmission electron microscopic effects of standardized MMC on nasal mucosa using various modalities of drug applications have been documented. The MMC affected all the components of the mucosa, including epithelium, glands, and vascular and fibrocollagenous tissues. The nasal mucosal fibroblasts show a dramatic structural response to MMC, including developing intracellular edema, pleomorphic and vesicular mitochondria, dilated smooth and rough endoplasmic reticulum, and chromatin condensation. Moreover, topical and COS-MMC showed profound changes in nasal mucosal fibroblasts, but the effects seem more marked in the COS-MMC group without any tissue necrosis. The ultrastructural evidence showed that MMC is likely effective against aggressive wound healing if used in appropriate doses with standardized techniques.