Ahmed Glaucoma Valve Implantation: Graft-Free Short Tunnel Small Flap versus Scleral Patch Graft after 1-Year Follow-up: A Randomized Clinical Trial

Failed Ahmed glaucoma valves: trabeculectomy versus repeat shunt surgery

INTRODUCTION

To investigate the outcomes of trabeculectomy (TRAB) versus repeat Ahmed glaucoma valve (re-AGV) implantation in eyes with Ahmed glaucoma valve (AGV) failure.

METHODS

This quasi-experimental study includes patients with failed AGV implants requiring additional surgical intervention between 2018 and 2022. Patients in the TRAB group underwent a fornix-based procedure with mitomycin C 0.01% injection (0.1 mL). Eyes in the re-AGV group underwent repeat shunt surgery. The choice of the procedure was based on conjunctival condition. The primary outcome measure was surgical success rate based on various intraocular pressure (IOP) targets and percentages of IOP reduction from baseline: IOP ≤ 21 mmHg and 20% reduction (conventional criteria), IOP ≤ 18 and > 20% reduction (criterion A), IOP ≤ 15 and > 25% reduction (criterion B), and IOP ≤ 12 and > 30% reduction (criterion C).

RESULTS

Forty-eight eyes of 48 patients were operated and reported herein, consisting of 22 eyes of 22 patients undergoing TRAB and 26 eyes of 26 subjects undergoing re-AGV. No significant difference was observed between the study groups in terms of initial diagnoses, baseline IOP or the number of prior surgeries. The cumulative probability of survival at one year was significantly higher in the trabeculectomy group using the three stricter success definitions. In both study groups, IOP was significantly reduced from baseline at all postoperative visits, and was significantly lower in the TRAB group at all time points beyond one month. At 12 months, 5% of TRAB versus 48% of re-AGV eyes required glaucoma medications (P < 0.001). The rate of complications was comparable between the study groups (P = 0.76) but there was a trend toward a greater need for repeat surgery in the re-AGV group (4 eyes versus nil, P = 0.07).

CONCLUSIONS

Trabeculectomy can be considered a safe and effective surgical option in eyes with failed AGV leading to significantly lower IOP levels and more favorable success rates than re-AGV in selected patients.

Scleral Grafts in Ophthalmic Surgery. A Review

AIM

To summarize the history and current trends in the use of scleral grafts in ophthalmology.

MATERIALS AND METHODS

We conducted a review of the literature through the MEDLINE and Cochrane Library databases. The search terms were "sclera", "graft", and "surgery". The search resulted in 1596 articles, of which we evaluated 192 as relevant. The relevant articles were sorted chronologically and according to the method of using scleral grafts, which enabled the development of a review article.

RESULTS

The sclera has been routinely used in ophthalmology since the 1950s in many different indications. Some of these indications have become practically obsolete over time (for example, use in the surgical management of retinal detachment), but a large number still find application today (especially use in glaucoma or oculoplastic surgery, or as a patch for a defect in the sclera or cornea).

CONCLUSION

Even though allogeneic sclera is currently used less frequently in ophthalmology compared to other tissue banking products and the range of its indications has partially narrowed, it remains a useful material due to its availability and properties.

Recent Advancements in Glaucoma Surgery-A Review

Surgery has long been an important treatment for limiting optic nerve damage and minimising visual loss in patients with glaucoma. Numerous improvements, modifications, and innovations in glaucoma surgery over recent decades have improved surgical safety, and have led to earlier and more frequent surgical intervention in glaucoma patients at risk of vision loss. This review summarises the latest advancements in trabeculectomy surgery, glaucoma drainage device (GDD) implantation, and minimally invasive glaucoma surgery (MIGS). A comprehensive search of MEDLINE, EMBASE, and CENTRAL databases, alongside subsequent hand searches-limited to the past 10 years for trabeculectomy and GDDs, and the past 5 years for MIGS-yielded 2283 results, 58 of which were included in the final review (8 trabeculectomy, 27 GDD, and 23 MIGS). Advancements in trabeculectomy are described in terms of adjunctive incisions, Tenon's layer management, and novel suturing techniques. Advancements in GDD implantation pertain to modifications of surgical techniques and devices, novel methods to deal with postoperative complications and surgical failure, and the invention of new GDDs. Finally, the popularity of MIGS has recently promoted modifications to current surgical techniques and the development of novel MIGS devices.

Ahmed Glaucoma Valve Implantation to Reduce Intraocular Pressure: Updated Perspectives

Trabeculectomy and glaucoma drainage device implantation are the most commonly performed glaucoma surgeries worldwide. Although trabeculectomy is the gold standard, at the present time there is an increase in the use of glaucoma drainage devices. The Ahmed glaucoma valve is one of the most widely used glaucoma drainage devices worldwide. Corneal endothelial cell loss and eventually corneal decompensation is one of the serious complication of glaucoma drainage device implantation. To avoid this, drainage tube can be inserted into the ciliary sulcus instead of the anterior chamber, especially in eyes with high risk for corneal decompensation. Tube/plate exposure, hypertensive phase, endophthalmitis, cataract formation, diplopia and ocular hypotony are the other potential complications that can develop after Ahmed glaucoma valve implantation.

A graft-free scleral sleeve technique of Ahmed Glaucoma Valve implantation in refractory glaucoma- Rising to the challenge of COVID-19 pandemic

We describe a case of 63-year-old woman, with primary open-angle glaucoma (POAG) who presented to us in the COVID era with uncontrolled intraocular pressure (IOP) on maximum medical therapy (MMT) in the right eye (OD), previously operated twice for trabeculectomy in (OD), and once in left eye (OS). A modified graft-free surgical technique of inserting the Ahmed Glaucoma valve (AGV) tube through a scleral sleeve was employed. Visual acuity and IOP remained stable during 6-month follow-up period.

Autologous Scleral Pocket Technique for Ahmed Glaucoma Valve Implantation with Pars Plana Tube Insertion for Neovascular Glaucoma

Specific postoperative complications, such as tube exposure and conjunctival erosion, have occurred despite the favorable surgical outcomes of tube shunt surgeries for refractory glaucoma. The new autologous scleral pocket technique is performed by inserting the tube into the vitreous cavity without using a donor scleral patch. The purpose of this study was to evaluate the surgical results of Ahmed glaucoma valve (AGV) implantation using this technique for neovascular glaucoma (NVG), which is one of the representative refractory types of glaucoma. This observational retrospective case series included 15 consecutive eyes of 15 patients with NVG who had undergone AGV implantation at Kobe University between January 2018 and December 2019. The mean preoperative intraocular pressure (IOP) was 37.2 ± 13.8 mmHg and the glaucoma drug score was 4.2 ± 2.2. The mean IOP and glaucoma drug score at 1 year postoperatively decreased to 15.0 ± 4.6 mmHg and 1.3 ± 2.0, respectively (p < 0.001). No significant change in the corneal endothelial cell density following surgery was observed (p = 0.09); however, one patient required an additional trabeculectomy at 7 months postoperatively. No cases of tube exposure or conjunctival erosion were observed at 1 year postoperatively. These results indicated the effectiveness and safety of this technique in patients with NVG.

Aurolab Aqueous Drainage Implant With and Without Scleral Patch Graft in Refractory Adult and Pediatric Glaucomas: A Comparative Study

PURPOSE

To compare the 2-year outcomes of eyes that received the Aurolab aqueous drainage implant (AADI) with and without a scleral patch graft.

DESIGN

Retrospective comparative interventional case series.

METHODS

Eyes with AADI and a minimum of a 2-year follow-up were included. Eyes that underwent implantation before January 2016 had surgery with a scleral patch graft covering the distal end of the tube, whereas those that were implanted after this period underwent surgery using a needle-generated scleral tunnel without the patch graft. The cumulative failure of the AADI was defined as intraocular pressure (IOP) >18 mm Hg or not reduced by 30% below baseline on 2 consecutive follow-up visits after 3 months.

RESULTS

We included 215 adult eyes (n = 147 with patch graft, n = 68 without patch graft) and 111 pediatric eyes (n = 73 with patch graft, n = 38 without a patch graft). The mean IOP in eyes without the patch graft was higher at 1 month in adult eyes (before, 27.5 ± 14.1 vs after, 22.3 ± 11.1; P = .01) but not in pediatric eyes (14.3 ± before, 5.8 vs after, 17.8 ± 11.0; P = .39); there were no differences in IOP, vision, number of antiglaucoma medications, and complications between groups at all other time points. None of the eyes without the patch graft experienced tube exposure. Cumulative success rates at 2 years in adults (66.2% vs 63.9%, respectively; P = .85) were similar to those in children (77.2% vs 71.9%, respectively; P = .83) with both techniques.

CONCLUSIONS

AADI placed without a scleral patch graft is as safe and effective as AADI placed with a patch graft in pediatric and adult refractory glaucomas.