Protection of the conjunctival flap from contact with mitomycin C during tunnel-trabeculectomy

The mid-term appearance of the filtering bleb and surgical outcome following tunnel-trabeculectomy, in which protective measures were carried out to avoid contact between the mitomycin C (MMC) and the conjunctival flap, are presented.

In a retrospective study the records of 20 consecutive patients who had undergone tunnel-trabeculectomy >/=24 months earlier, using fornix-based conjunctival flap and MMC (0.4 mg/ml) application were evaluated. Inclusion criteria were patients in whom: (I) the MMC-socked sponge was applied without contact with the conjunctival flap; (II) during MMC washout, a second Weck cell sponge was held anterior to the conjunctival flap, to protect the flap from mitomycin contact during its back-flow. Excluded were five patients who either did not complete 24 months of follow-up (n=4) or underwent an intraocular surgery during that period (n=1).

After 24-32 (26.9+/-2.2) months, the filtering bleb was completely vascularized and thick in 13/15 patients (86.7%), mostly vascularized with some para-limbal thick cysts in one and avascular and cystic in another. Mean intraocular pressure (IOP) dropped from a preoperative level of 25.3+/-7.0 mmHg with 3.5+/-0.9 hypotensive medications to 13.9+/-2.9 mmHg with 0.9+/-1.1 medications (P<0.0001, Wilcoxon test). Of the five excluded patients, the IOP ranged between 10 and 16 mmHg with 0-1 medications at the last examination, 1-15 months postoperatively.

In this pilot study, an intraoperative protection of the conjunctival flap from mitomycin contact was mostly associated with a vascularized and thick filtering bleb after mid-term follow-up. Further controlled prospective studies are required to confirm these observations.