Outcome of repeat trabeculectomy with mitomycin C in isolation or combined with phacoemulsification

Purpose: To evaluate the effectiveness of repeat trabeculectomy with Mitomycin C (MMC) in isolation or combined with phacoemulsification, and to identify risk factors for failure over 1 year. Methods: Retrospective review of 113 eyes of 113 patients (49 primary open angle, 27 primary angle closure, 37 secondary glaucoma) who underwent repeat trabeculectomy with MMC (isolated trabeculectomy 75 and phacotrabeculectomy 38). The primary outcome measure was intraocular pressure (IOP) at 1 year follow-up. Three IOP criteria were chosen to measure success A) IOP <= 21 mmHg and >= 20% reduction from baseline. B) IOP <= 17 mmHg and >= 20% reduction from baseline. C) IOP <= 14 mmHg. Results: Mean IOP decreased from 24.5 +/- 8.8 mmHg to 16.4 +/- 7.6 mmHg 1 year after repeat trabeculectomy. The mean number of medications reduced from 2.9 +/- 1.0 to 0.6 +/- 1.0. Complete success with trabeculectomy versus phacotrabeculectomy for criterion A was 60% vs 55.3%, criterion B 54.7% vs 50.0% and criterion C 40.0% vs 28.9%. IOP <= 14 mmHg was more likely with trabeculectomy than phacotrabeculectomy (P = 0.047). On regression analysis, duration between surgeries <= 14 years (P = 0.018) and secondary glaucoma (P = 0.046) were identified as risk factors for surgical failure with criterion A. Younger age (P = 0.042), fornix based flap (P = 0.058), and phacotrabeculectomy (P = 0.042) for criterion C. Conclusion: Repeat trabeculectomy with MMC is successful at lowering IOP and decreasing number of antiglaucoma medications. Low IOP levels are less likely with phacotrabeculectomy.