Outcomes of Ahmed valve implant following a failed initial trabeculotomy and trabeculectomy in refractory primary congenital glaucoma

Abstract

Purpose:The aim was to report the outcome of Ahmed glaucoma valve (AGV) (New World Medical, Inc., Rancho Cucamonga, CA, USA) implantation as a surgical intervention following an initial failed combined trabeculotomy + trabeculectomy (trab + trab) in refractory primary congenital glaucoma (RPCG).Materials and Methods:Retrospective chart review of 11 eyes of 8 patients who underwent implantation of AGV (model FP8) for RPCG between 2009 and 2011. Prior trab + trab had failed in all the eyes. Success was defined as an intraocular pressure (IOP) >5 and ≤ 18 mmHg during examination under anesthesia with or without medications and without serious complications or additional glaucoma surgery.Results:The mean age at AGV implantation was 15.4 ± 4.9 months. The mean preoperative IOP was 28 ± 5.7 mmHg which reduced to 13.6 ± 3.4 mmHg postoperatively at the last follow-up (P < 0.0001). The number of topical antiglaucoma medications reduced from a mean of 2.6 ± 0.5 to 1.6 ± 0.9 postoperatively (P = 0.009). The definition of qualified success was met in 10 (90%) eyes. One eye developed a shallow anterior chamber with choroidal detachment at 1-week, which resolved spontaneously with medications. None of the eyes developed a hypertensive phase. One eye had a long tube resulting in tube corneal touch that required trimming of the tube. One eye developed tube retraction, which was treated with a tube extender. The mean follow-up was 17.9 ± 9.3 (6.2-35.4) months.Conclusion:Managing RPCG remains a challenge. AGV implant was successful in a significant proportion of cases.

Primary congenital glaucoma: An updated review

“…The use of anti-metabolites, such as mitomycin C (MMC), in PCG patients has been reported in some studies to improve success rates of surgery, quoted as 52–82% 73, 74. The use of MMC is preferred in refractory cases, aphakic eyes, and older children 75, 76, 79. Although some are doubtful about the application of MMC in children, evidence suggests that its use is safe and postoperative complications encountered are similar to those seen in adults 76, 77.…”

Review on the Management of Primary Congenital Glaucoma

“…Retrospective studies on Ahmed glaucoma valve (AGV) revealed a 28 to 49% reduction in the mean IOP and a success rate ranging from 63 to 97% at 1 year. 66 - 68 The definition of success is similar across studies, which is defined as absence of serious complications or lost of light perception, with an acceptable IOP with or without the use of medication, thought the acceptable IOP ranges from 18 to 23 mm Hg across studies. 66 - 68 Hispanic ethnicity and gender female have been reported to be independent predictors for failure of the GDD procedure, but the underlying reason has yet to be identified.…”

“… 73 It has been suggested that GDD may be preferable to trabeculectomy when conjunctival scarring is evident, 74 or in buphthalmic eyes with very thin sclera. 66 It is hypothesized that as the bleb is located more posteriorly in GDD, the long-term risk of infection is, thus, theoretically lower. 66 However, GDD is associated with more complications that requires re-operation than trabeculectomy (46% vs 13%), in particular displacement of tube leading to tube-endothelial touch and tube retraction.…”

The Choice of Drainage Device in Complicated Glaucomas: Comparing Ahmed and Baerveldt Implants

“…Furthermore, these patients used a significantly lower number of medications postoperatively (1.6 vs. 2.6 preoperatively), as our patients did. The referred complications included shallow anterior chamber with choroidal detachment at 1 week, which resolved spontaneously with medications, tube corneal touch and tube retraction(15).…”