5-Fluorouracil augmented needle revision of trabeculectomy: does the location of outflow resistance make a difference?

Abstract

Purpose: To determine whether the outcome of needle revision of trabeculectomy is influenced by the presumed anatomic location of resistance to aqueous outflow.

Design: Retrospective case note review.

Participants: Thirty-four eyes of 30 consecutive patients undergoing their first needle revision of trabeculectomy.

Methods: We compared 2 types of needle revision: "type-1 needling," limited to breaking down fibrosis in the subconjuctival-subtenon space, and "type-2 needling," which additionally involved needling underneath the scleral flap.

Main outcome measures: Unqualified success was defined as a postneedling intraocular pressure (IOP) >4 mm Hg and ≤21 mm Hg at the most recent follow-up without further surgery, medications, or repeat needling. Qualified success was defined as a successful patient who required medications or repeat needling.

Results: The mean follow-up period was 2.1 ± 0.1 years (range, 1.0 to 3.8 y). Sixteen type-1 and 18 type-2 procedures were performed at a median of 124 days (22 d to 14 y) after trabeculectomy. IOP decreased from a mean of 28.2±1.3 mm Hg (19 to 52 mm Hg) preneedling to 6.7±0.8 mm Hg (2 to 22 mm Hg) on the first postoperative visit and 15.1±0.7 mm Hg (8 to 27 mm Hg) at the most recent follow-up. The overall success rate was 82.4% (47.1% unqualified and a further 35.3% qualified). There was no significant difference in the success rates between type-1 (14/16) and type-2 (14/18) needle revisions (Fisher exact test, P=0.66). Similar proportions of eyes undergoing type-1 and type-2 needling underwent a second needling procedure. There was no significant difference in the IOP reduction between type-1 and type-2 needling (Mann-Whitney U test, P=0.78).

Conclusions: Needle revision is an effective technique for trabeculectomy bleb remodeling and can result in a sustained reduction in IOP. The location of the obstruction did not influence outcome, with type-1 and type-2 needle revisions equally likely to succeed.