Long-term surgical outcomes of two different Ahmed Valve implantation techniques in refractory glaucoma: Scleral flap vs scleral tunnel

Abstract

Purpose To compare the outcomes and complications of the partial-thickness scleral flap technique to the long scleral tunnel technique in patients who underwent mitomycin C (MMC)-augmented Ahmed glaucoma valve (AGV) implantation. Patients and Methods In this retrospective study, we reviewed 139 eyes of 137 patients with refractory glaucoma who underwent AGV-Model FP7 implantation. The eyes were divided into the scleral flap group (n = 74) and the scleral tunnel group (n = 65). Results The mean follow-up was 57.91 ± 18.18 months for the flap and 61.18 ± 15.13 months for the tunnel group (p = 0.2499). The postoperative intraocular pressure (IOP) at 1 to 6 years was significantly lower than the baseline IOP in each group (p < 0.001). The average number of postoperative glaucoma medications decreased in the tunnel group (p = 0.0001) and in the flap group (p = 0.6194) compared to baseline. No statistically significant differences in postoperative visual acuity (p = 0.6396) and cumulative success (p = 0.054) were noted between the two groups. Conjunctival erosion or tube migration only occurred in the flap group. Significantly more reoperations were performed in the flap than in the tunnel group (p = 0.048). Conclusions Both MMC-augmented AGV tube implantation methods lowered IOP. The flap technique was associated with higher rates of postoperative serious complications and more reoperations than the tunnel technique. Previous glaucoma surgery and the technique used to implant the surgical tube proved to be significant risk factors for conjunctival erosion.

Comparison of Tenon duplication with dura mater covering technique for Ahmed glaucoma valve implantation

“…[ 20 ] Although there are many comparative studies on tube covering techniques such as scleral flap and scleral tunnel techniques, pericardium, and lyophilized sclera, there are limited reports on dura mater covering and Tenon duplication techniques in AGV implantation surgery. [ 21 22 ] The present study compares the Tenon duplication technique and dura mater covering in terms of postoperative complications and the success rate.…”