European Journal of Biomedical and Pharmaceutical Sciences

THE ROLE OF MITOMYCIN-C (MMC) IN PRIMARY PTERYGIUM SURGERY FOR PREVENTION OF RECURRENCE

Dr. Hashim Thiab Hassan*

ABSTRACT

Backgroud: Pterygium is a fibrovascular wing shaped, sub-epithelial fleshy ingrowth of bulbar conjunctival tissue which can spread to the corneal limbus and beyond. Pterygium is now accepted as a distorted wound-healing response and dys-regulated cell proliferation disease rather than a degenerative lesion. The stromal overgrowth of fibroblast and blood vessels is accompanied by an inflammatory cells infiltrate and accumulation of abnormal extracellular matrix. Pterygia are relatively common in the general population and typically follow an indolent course. It is a common health problem in Iraq because of dry hot climate. Simple excision of the pterygium alone has a very high recurrence rate. Many adjunctive methods have been used to reduce the recurrence such as chemical agents like mitomycin-C (MMC). The mechanism of action of MMC seem to inhibit fibroblast proliferation at the level of the episclera. The aim of study was to evaluate the effect of intraoperative MMC 0.04%(0.4 mg/ml) for 3 minutes on pterygium recurrence and complications after surgical removal with the bare sclera resection (BSR) technique. Patients And Methods: Prospective non-comparative interventional study was conducted at Eye unit, Alyarmouk Teaching Hospital. Fifty patients with primary nasal pterygium were selected. Detailed history was taken. Complete ocular examination done and those fulfilling inclusion criteria were applied in the study. We used topical proparacaine 0.5% and local infiltration of 2% lidocaine with 1:200.000 adrenaline, to all patients freshly prepared MMC 0.04% (0.4mg/ml) for 3 minutes was applied through a sponge spear at the bare part of the sclera then the eyes were thoroughly rinsed with a 100ml sterile balanced salt solution (BSS). Average surgery time was 20 minutes (range: 15–25min). All patients received topical corticosteroid and antibiotic treatment for at least 4 weeks postoperatively. All patients were followed for a minimum of one year and recurrence rates and complications were assessed after 3, 6, 9, and 12 months. Recurrence defined as fibrovascular tissues invading the cornea 1mm or more. Results: We recruited 50 eyes of 50 patients, 33 female patients and 17 male patients, with 26 right and 24 left eyes. Age range from 21-60 years, mean age at operation was 42.55 years. The size of pterygium on cornea was 2-5mm. Average surgery time was 20 minutes (range: 15–25min). Recurrence was defined as 1 mm fibrovascular tissue over the corneascleral limbus onto clear cornea in the area of previous pterygium excision. Two recurrent cases encountered (recurrence rate 4%), one male after 3 months and another female after 6 months, the mean is 4.5 months. The side effects encountered were: ocular discomfort, phtophobia, lacrimation, foreign body sensation, and ocular pain in 35 cases(70%). Chemosis, oedema & hyperemia of surrounding conjunctiva in 30 cases (60%). Superficial punctate keratitis in 2 cases (4%). Conjuctival avascularity in areas of pterygium excision in 15 cases (30%). Avascularised sclera in 25 cases(50%) between 1-6 months postoperatively. Granuloma in one case after 1 month (2%). The adverse side effects were all mild, self limiting, and easily treated. No patients experienced severe complications during 1 year of postoperative follow-up. Conclusion: A single intraoperative application of 0.04% (0.4mg/ml) MMC for 3 minutes after BSR technique of pterygium is associated with minimal complication and effectively reduces the recurrence rates. We prefer BSR technique followed by intraoperative MMC which was safe,simple and acceptable adjuvant for prevent recurrence, in comparism to MMC eye drops postoperatively in which the risk of overuse from self-administration of this toxic chemotherapeutic agent by the patients themselves at home, and postoperative therapy entails repeated bathing of the entire ocular, nasolacrimal, and oropharyngeal surfaces for 5–14days with MMC which carry high serious side effects and also prefer to another technique like conjuctival autograft (CAG) which is technically more difficult, time consume and inapplicable in cases with previous conjuctival disturbance.

Keywords: bare sclera resction (BSR), blanced salt solution(BSS), conjuctival autograft (CAG), mitomycin-C (MMC), intraoperative(IO), postoperative(PO), pterygium, recurrence, ultraviolet (UV).