Objective: To investigate the risk factors for failure of 5-fluorouracil (5-FU) needling revision, a useful procedure for restoring a failed filtration bleb.

Methods: Interventional case series. Methods: Retrospectively conducted study. Methods: Institutional. Methods: Sixty-four eyes of 64 consecutive glaucoma patients that underwent 5-FU needling revisions for failed filtering bleb following either trabeculectomy or phaco-trabeculectomy with or without adjunctive mitomycin C (MMC). Methods: Goldmann applanation tonometry, Kaplan-Meier survival analysis, and Cox proportional hazards regression analysis. Methods: Successful outcome of the initial 5-FU needling revision, arbitrarily defined as target intraocular pressure (IOP) control with not more than two topical glaucoma medications and no additional 5-FU needling or other surgical procedures, was analyzed by Kaplan-Meier survival analysis, and risk factors for failure of the initial 5-FU needling revision were analyzed by Cox proportional hazards regression analysis.

Results: The cumulative success rate of the initial 5-FU needling revision was 45% at 1 year, 33% at 2 years, and 28% at 4 years. Failure of the initial 5-FU revision correlated significantly with preneedling IOP > 30 mm Hg (P =.0003), lack of MMC use during the previous filtration surgery (P =.013), and IOP >10 mm Hg immediately following needling revision (P =.0012) according to Cox's proportional hazards regression analysis.

Conclusions: Pre-needling IOP > 30 mm Hg, lack of MMC use during the previous filtration surgery, and IOP > 10 mm Hg immediately after needling were found to be significant risk factors for failure of the initial 5-FU needling procedure. Therefore, it is important to monitor IOP closely following needling revision in those patients with such risk factors. They are more likely to require additional therapeutic interventions, including repeat needling revisions.