Abstract
Abstract: :
Purpose: To identify the risk factors that make certain patients prone to failure of their Baerveldt glaucoma implant. Prior studies reported a 19 to 53% failure rate. What risk factors contribute to this high failure rate in both the "normal" and refractory glaucoma population? Methods: We retrospectively reviewed the medical records of the 203 patients who had Baerveldt implant surgery performed at the Bascom Palmer Eye Institute between July 1995 and September 1997. We gathered demographic data to include age, gender and race. Pre and post–operative information was collected including: the specific glaucoma diagnosis, glaucoma medications, surgical history, visual acuity and intra–ocular pressure measurements. We recorded operative data such as: implant size, implantation quadrant, ligation material, tube location, tube fenestrations, patch graft material and concomitant surgery. We also compiled a list of post–operative complications and whether the patient required further surgery. Failure was defined as having a sustained pressure over 21 mm Hg, hypotony with two lines of vision loss, reoperation for pressure control or surgical revision of the Baerveldt implant. Results: The 183 patients, with at least 3 months of follow–up, were divided into five diagnostic categories: primary open angle glaucoma, neo–vascular glaucoma, uveitic glaucoma, chronic angle closure glaucoma and "other" glaucoma. The "other" glaucoma cases failed the most often (50% versus 25% at five years.) The reasons for failure, listed in descending order, were: need for tube revision, re–operation for pressure control, and pressure above 21 mm Hg and hypotony with pressure below 5mm Hg. A multivariate analysis revealed four statistically significant risk factors associated with Baerveldt failure. The African–American race and anything other than supero–temporal tube placement are significant risk factors. The 350 mm implant fails less often than the 250 mm implant. Lens status is also important risk factor. Aphakes have the highest percentage of failures, while pseudophakes are at moderate risk and phakic patients are the least likely to fail. Age, pre–operative intra–ocular pressure and number of prior incisional surgeries were not statistically significant risk factors. Conclusions:A 350 mm Baerveldt implant, placed in the supero–temporal quadrant, of a phakic, non–black patient has the greatest chance for success. The 5–year survival of a Baerveldt implant was relatively equal for patients with primary open angle glaucoma, neo–vascular glaucoma, uveitic glaucoma or chronic angle closure glaucoma.
Keywords: anterior segment • clinical (human) or epidemiologic studies: risk factor assessment • clinical (human) or epidemiologic studies: outcomes/complications