The Short-term Effect of Subtenon Sponge Application Versus Subtenon Irrigation of Mitomycin-C on the Outcomes of Trabeculectomy With Ex-PRESS Glaucoma Filtration Device: A Randomized Trial
Traditionally, during trabeculectomy, Mitomycin-C (MMC) is applied to the tissues using surgical sponges. However, alternate modes of application exist. This study assessed the success rates, complication rates, final intraocular pressure (IOP), and bleb characteristics between patients receiving subtenon MMC application by sponge versus irrigation.Patients and Methods:
A total of 100 patients with glaucoma were enrolled and each was randomized to 1 of the 2 treatment groups. Patients underwent trabeculectomy with Ex-PRESS shunt and MMC placement and were followed for 6 months. Complication rates assessed included bleb failure, bleb leaks, bleb encapsulation, and hypotony, amongst others. Additional factors evaluated included bleb morphology, glaucoma drop usage, Fluorouracil (5-FU) application, bleb revision, and subsequent glaucoma surgery.Results:
The irrigation method provided greater IOP lowering effects (P=0.03); correspondingly the irrigation group had higher rates of hypotony (P=0.03) but with no significant consequences. Patients who had trabeculectomy/Ex-PRESS alone had greater IOP reduction than those who had concurrent cataract surgery (P<0.001). The sponge group had higher rates of 5-FU use (P=0.007) and higher reoperation rates (P=0.02) when compared with the irrigation group. Success was defined as achieving 4 mm Hg≤IOP≤15 mm Hg without any anatomical bleb failure or subsequent glaucoma surgery. The overall success rate was 87%.Conclusions:
Application of subtenon MMC by irrigation seems to provide improved short-term outcomes compared with application with sponges. With a similar safety profile, the irrigation method provides better IOP control, and decreases the need for further clinical/surgical intervention in the short-term after trabeculectomy. Longer-term studies will be useful in analyzing if these differences persist with time.