Trabeculectomy With Extended Subscleral Tunnel Versus Conventional Trabeculectomy in the Management of POAG: A 1-Year Randomized-controlled Trial.

PRECIS: This clinical trial compares a modified trabeculectomy technique [extended subscleral tunnel (ESST)] with conventional trabeculectomy [subscleral trabeculectomy (SST)] in terms of success rate and bleb morphology. ESST showed comparable results, with lower incidence of bleb-related complications and need for postoperative antiglaucoma medications.

BACKGROUND

To evaluate the outcome of modified trabeculectomy with extended subscleral tunnel "ESST" versus conventional subscleral trabeculectomy "SST" in the management of uncontrolled primary open-angle glaucoma.

PARTICIPANTS AND

METHODS

This is a randomized clinical trial of 40 eyes (40 patients) divided into 2 equal groups. In the first group, a conventional SST with adjuvant 0.3% mitomycin-C was performed. In the second group, the ESST group, an additional 1.00 mm wide longitudinal scleral groove was dissected and excised in the center of the deep scleral bed extending 1.00 mm beyond the posterior margin of the flap. Patients were examined on days 1, 7, 14, 30, 90, 180, and at 1 year, with a special focus on intraocular pressure and bleb morphology. Postoperative ultrasound biomicroscopy was performed to evaluate the surgical area.

RESULTS

Both groups showed a significant reduction in intraocular pressure, with the ESST group showing significantly lower values on days 7, 14, 30, 90, and 180 (P=0.001, 0.004, 0.026, 0.001, and 0.048), but no significant differences on day 1 and at 1 year (P=0.06 and 0.07). The need for postoperative antiglaucoma medications was significantly lower in the ESST group (P=0.043). Visually significant cataract and bleb related complications were more in the SST group (P=0.044 and <0.001). Significantly more eyes in the ESST group showed normal bleb vascularity and wider extent.

CONCLUSIONS

ESST offers a guarded posterior flow with a success rate comparable to that of conventional SST. ESST could minimize bleb-related complications and bleb-dysesthesia with better long-term bleb morphology and vascularity. It could also minimize the need for further adjuvant postoperative antiglaucoma medications.