Abstract
Purpose:
Glaucoma drainage devices (GDDs) for refractory pediatric glaucoma can fail to control intraocular pressure (IOP) by several mechanisms. In addition to encapsulation, fibrovascular ingrowth can limit outflow in valved Ahmed GDDs. This study evaluates initial GDD failure and subsequent GDD placement for refractory pediatric glaucoma.
Methods:
Ongoing, retrospective review of all patients having >2 GDDs for refractory pediatric glaucoma, >6mos follow up, single surgeon, 1/1995-8/2012. Data collected included glaucoma diagnosis, age at surgery, surgical interventions, pre-/post-operative IOP and medications, complications. Failure defined as IOP>21mmHg (or clinically inadequate), and/or IOP-reducing surgery/devastating complication
Results:
Included to date are 33 eyes (27 patients) having >two GDDs. Glaucoma diagnoses included congenital/infantile (n=13eyes), aphakic (n=10eyes), uveitic (n=5eyes), and other (n=5eyes). Average age at second GDD was 10.6±7.3yrs, with mean IOP 30±12mmHg, on 3±1 medications. Initial GDDs implanted were: Ahmed (New World Medical, Inc., Rancho Cucamonga, CA, n=28), Baerveldt (Abbott Medical Optics, Abbott Park, IL, n=5). Fibrovascular ingrowth-sometimes unsuspected, and confirmed under anesthesia by bleb needling-was documented at second GDD surgery in 13/33 eyes (39%), and only in Ahmed GDDs [models S2 (n=4), FP7 (n=4), S3 (n=3) ,unspecified (n=2)]. Mean time to failure of initial Ahmed GDDs by fibrous ingrowth was 70 months (range 11-153). Second GDDs placed were: Ahmed (same location/replacing Ahmed, n=8; different location, n=13); Baerveldt (same location/replacing Ahmed, n=6; different location, n=6). Failure of second GDDs occurred in 15/33 eyes (45%): 10/15 (67%) underwent third GDD surgery, 3/15 (20%) had endoscopic laser cycloablation, and 2/15 (13%) suffered retinal detachment.
Conclusions:
Published studies report failure of Ahmed models S2 and S3 from fibrovascular valve chamber ingrowth, but similar reports for the newer FP7 model are lacking. This study documents fibrovascular ingrowth of Ahmed FP7 GDDs in pediatric glaucoma. Fibrovascular ingrowth commonly causes Ahmed GDD failure in refractory pediatric glaucoma, and may be under-diagnosed.
Keywords: 462 clinical (human) or epidemiologic studies: outcomes/complications •
568 intraocular pressure •
427 aqueous