Scleral free auto-implant plug with mitomycin as limitation of trepanosclerectomy flow in glaucoma filtering surgery.

The purpose of this study is to evaluate the effect of trephination with free scleral auto-implant plug exposed to Mitomycin-C out of the eye, in surgical treatment of primary open-angle glaucoma (POAG), in comparison with efficacy of trabeculectomy with MMC (32 eyes with POAG of patients, younger than 55 years-group 1). Trephination with scleral auto-implant plug with MMC was done on 35 eyes of patients, younger than 55 years, with POAG (group 2). The postoperative follow-up was 28.52 +/- 8.78 months.

Methods: A limbal 1.0 mm diameter trephination is made beneath the limbus-based conjunctival flap, a small iridectomy is performed. From the external layers of the trephine button one third of the corneoscleral thickness, in the form of a thin disc, is excised. The scleral disc, a free auto-implant, is dipped into liquid containing MMC with concentration 0.2 mg/ml for 5 minutes, outside the eye. Afterwards the scleral disc soaked with MMC is carefully irrigated with 150 ml of BSS and placed in the external part of the trephine fistula in primary position and stabilized with two interrupted 10-0 nylon sutures. The operation is ended as a typical trabeculectomy. The final success rate in terms of IOP (IOP < 14 mmHg) was 100%, without or with antiglaucoma medication, in both groups, but the number of postoperative complications was significantly lower in group 2. Trephination with free scleral auto-implant plug soaked with MMC may represent a viable alternative to trabeculectomy with MMC; the scleral plug may be taken out of the eye and exposed to antimetabolite outside the eye to minimize toxicity.