Second glaucoma drainage devices in refractory pediatric glaucoma: Failure by fibrovascular ingrowth

Purpose To evaluate initial glaucoma drainage device failure and subsequent glaucoma drainage device placement for refractory pediatric glaucoma. Design Retrospective interventional case series. Methods The Duke University surgical records from a single surgeon from 1997 to 2012 were reviewed for patients having at least 2 glaucoma drainage devices for refractory pediatric glaucoma. Data collected included glaucoma diagnosis, age at surgery, surgical interventions, preoperative/postoperative IOP and medications, and complications. Failure was defined as having an IOP >21 mm Hg (or clinically inadequate), and/or IOP-reducing surgery/devastating complication. Results Forty-three eyes (37 patients) had 2 or more glaucoma drainage devices. Mean age at second glaucoma drainage device implantation was 9.2 ±7.1 years, with mean IOP 30 ±11 mm Hg, on 3 ± 1 IOP-lowering medications. Fibrovascular ingrowth was documented during second glaucoma drainage device surgery in 12 of 43 eyes (28%), occurring only in Ahmed devices, at a mean of 70 months (range 11-153) after initial implantation. Failure of the second glaucoma drainage device surgery occurred in 18 of 43 eyes (42%) at mean 26.1 ± 32.2 months (median 19.3 months). Surgical success of second glaucoma drainage devices (Kaplan-Meier analysis) at 1 year, 2 years, and 3 years was 81%, 62%, and 50%, respectively. Conclusions Single glaucoma drainage device surgery fails to control IOP in some eyes with refractory pediatric glaucoma. Second glaucoma drainage device implantation offers a treatment option with modest success over time. Fibrovascular ingrowth should be suspected as a relatively common cause of IOP elevation and failure after Ahmed device implantation.