Efficacy and Security of Bleb Needling Revision in Failed Trabeculectomies of Glaucoma Patients: A 10-Year Retrospective Study (2004-2014)

When the reason for a trabeculectomy failure is deemed to be an excess of fibrous tissue preventing the activity of the fistula, one has to opt for either a conservative management or a more aggressive interventional approach. In the decision making process many variables need to be born in mind: the mechanism of glaucoma, the technique employed for the original surgery, the state of the conjunctiva, the eventual comorbidities, the time to failure from the original surgery and the patient’s preference are some of them. The conservative management usually relies on the use of topical aqueous suppressants, such as carbonic anhydrase inhibitors, alpha-2 agonists and beta-blockers. Conversely, the interventional approach frequently consists in the attempt to revive the bleb function via bleb needle revision (BNR). BNR is performed entering the conjunctiva far back from the filtering site and puncturing and cutting the fibrous tissue around the bleb with sweeping motion in the attempt of increasing the outflow. The procedure is often associated with the use of antimetabolites to enhance the chances of success. One of the most common is the pyrimidine analogue 5-fluorouracil (5-FU) which is injected under the conjunctiva. The opinion on the efficacy of the BNR is still debated: some believe that should be avoided in the first place, as it jeopardizes the remaining function of the bleb; others strongly advocate its use early on, even when the trabeculectomy activity seems adequate but the morphology of the bleb appears suboptimal. The aim of this study is to cast some light on the safety and efficacy of bleb needling revision performed on partly or completely failed trabeculectomies. Procedures carried out during a time window of 10 years (2004-2014) in the same setting (Moorfields Eye Hospital, NHS Trust, London, UK) with a consistent technique were included in the study.