Late Needling of Flat Filtering Blebs with Adjunctive Mitomycin C: Efficacy and Safety for the Corneal Endothelium

Abstract

To assess the efficacy of needle revision using mitomycin C (MMC) for reviving failed filtering blebs during the late postoperative period and its safety for the corneal endothelium. Prospective interventional case series. We recruited 125 eyes from 98 patients with uncontrolled glaucoma. All had at least 1 failed trabeculectomy, a flat filtering bleb, and a patent internal ostium on gonioscopy. The average time between the last trabeculectomy and needle revision was 5.3±5.3 years (range, 6 months to 30 years). Needling revision with a subconjunctival injection of 8 μg of MMC. Intraocular pressure (IOP) and number of hypotensive medications at latest visit, central corneal thickness (CCT), corneal endothelial cell density (ECD), coefficient of variation of cell size (CV), and hexagonality before and after needling. We performed 186 needling procedures on 125 eyes (mean, 1.5±0.6 procedures/eye). Seventy-three eyes (58.4%) were needled once, 44 eyes (35.2%) were needled twice, 7 eyes (5.6%) were needled 3 times, and 1 eye (0.8%) was needled 4 times. We reestablished aqueous flow and obtained a raised bleb in 115 eyes (92%). After an average follow-up of 20.8±12.0 months, the mean IOP decreased from 20.1±5.2 mmHg preoperatively to 13.2±6.8 mmHg (P<0.001), and the mean number of hypotensive medications per eye decreased from 2.4±1.1 to 0.8±1.3 (P<0.001) at the latest visit. The overall success rate (IOP ≤16 mmHg) was 76% (58.4% without medication and 17.6% with hypotensive medications). Kaplan-Meier survival rates were 91.2% at the 1-month follow-up, 84.5% at 6 months, 81.0% at 1 year, 74.6% at 2 years, and 66.3% at 3 years. We studied the corneal endothelium in 42 eyes of 36 patients. There was no statistically significant difference between preoperative CCT, ECD, CV, or hexagonality and postoperative measurements at 1 week and 1, 3, 6, and 12 months. Needling revision with adjunctive MMC is effective for reviving flat filtering blebs and controlling IOP, even several years after the original trabeculectomy, and seems to be safe for the corneal endothelium.