Needling revision of trabeculectomies bleb morphology and long-term survival.

PURPOSE

To assess the long-term success rate and to determine factors that predict survival after 5-fluorouracil-augmented needling revision of poorly functioning trabeculectomy blebs.

DESIGN

Prospective observational cohort study.

PARTICIPANTS

Eighty-one consecutive patients undergoing bleb needling.

METHODS

Survival analysis was performed after a minimum of 2 years' follow-up. Cox proportional hazards regression analysis was used to test the association between survival and study variables, including bleb morphology.

MAIN OUTCOME MEASURES

Intraocular pressure (IOP) reduction by >20% and to <or=21 mmHg (definition 1) or IOP reduction by >20% and to <or=16 mmHg (definition 2).

RESULTS

The mean follow-up period was 3.4 years. Survival rates were 64.2%, 54.3%, 45.7%, 31.9%, and 13.0% at 6, 12, 24, 36, and 48 months, respectively, with mean survival of 123.8 weeks (95% confidence interval [CI], 96.3-151.3; median, 74.0) using definition 1. Results for definition 2 were not significantly different. Survival time was shorter if multiple needlings were employed (P = 0.04) or if an immediate reduction in IOP to <or=10 mmHg was not achieved (P<0.001). Preneedling elevated bleb morphology was predictive of survival in comparison with flat blebs (P = 0.02), but this effect was significantly modified by (1) the interval between trabeculectomy and needling, (2) degree of bleb vascularization, and (3) presence of microcysts. Elevated blebs needled within 3 months of trabeculectomy or blebs that were also highly vascularized or microcystic were more likely to survive than flat blebs by factors of 4.7, 4.3, and 3.0, respectively (P = 0.002, P = 0.007, and P = 0.015, respectively). A higher proportion of blebs needled early after trabeculectomy survived to 12 months, but the timing of needling did not by itself significantly predict survival in the long term.

CONCLUSIONS

Needling with 5-fluorouracil is an effective intervention in the short to medium term, but long-term results show that additional intervention is necessary in the majority of cases. Bleb morphology can be used to predict success in recent, highly vascularized, or microcystic trabeculectomy blebs.