Needling after XEN gel implant: What's the efficacy? A 1-year analysis

To analyse the long-term efficacy and safety of bleb needling in glaucoma patients previously submitted to XEN implantation.

Retrospective, observational study. Charts from patients who underwent XEN gel implant surgery between October 2015 and December 2017 were reviewed. Needling protocol involves use of Mitomycin C 0.2 mg/mL in an operating room. Primary outcome was defined as intraocular pressure (IOP) lowering efficacy at 12 months post-operative. Complete success was defined as a decrease in IOP > 20% and overall value <18 mmHg. Secondary outcomes included safety parameters (both intra and post-operative). Exploratory analysis of predictive factors for success were performed. Statistical analysis was performed using SPSS version 24.

About 94 charts were reviewed, with 18 patients (19%) having undergone needle revision. This salvage procedure was performed after 3.3 ± 3.4 months, achieving a mean IOP reduction of 8.3 ± 8.4 mmHg at 12 months after the procedure (pre-needling: 24.0 ± 5.2 mmHg vs 12th month: 13.5 ± 5.9 mmHg, p < 0.0001). Accordingly, success was achieved in 72% (complete success in 61% of cases). Among predictive factors, there was a higher tendency for success in patients on two types of medications or fewer pre-operatively, cases of standalone XEN surgery and patients with a higher IOP difference pre-needling - day 1. No vision-threatening complications were recorded.

XEN salvage procedure with mitomycin C is a valid option in early bleb failure. This single intervention had a long-lasting effect on bleb survival, with almost two-thirds achieving long term significant drop-free IOP reduction.