The Outcome of Baerveldt Implant with Pars Plana Modification

Abstract

Abstract: : Purpose:To assess the safety and efficacy of the Baerveldt glaucoma drainage device (GDD) with the Hoffman modification for pars plana implantation in the treatment of refractory glaucomas. Methods:All patients identified to have pars plana Baerveldt GDD’s from the operating room’s supply records in a single speciality eye hospital were enrolled in a retrospective, non–comparative case series. All eyes underwent pars plana vitrectomy followed by implantation of 350 mm² Baerveldt GDD with Hoffman modification, after intraoperative application of Mitomycin–C (0.4 mg/ml) for 5 minutes. To avoid excessive flow in the early post–operative period, all tubes were stented with an intraluminal 3/0 braided nylon (Supramid) suture in addition to either a vicryl external ligature or gas–fluid exchange. Outcome measures included; glaucoma medications, IOP, visual acuity and complications. Qualified and complete successes were defined as IOP of < 22 mmHg with or without glaucoma medications respectively. Results:19 eyes of 17 patients (8 men and 9 women) were identified and case notes reviewed, the average age was 49 years (range 10 – 80).They were followed up for an average of 15 months (range 4– 34). The mean pre operative IOP was 30 mmHg (range 12 –63), on an average of 3 medications (range 1–4). The average final postoperative IOP was 13 mmHg (range 4–22) on an average 0.4 glaucoma medications (range 0–3). Complete and qualified success at the final follow up were 68% (13/19) and 84% (16/19) respectively. Hypotony occurred in 5 eyes and two of which were persistent, and two eyes had tube blockage by vitreous strands. Erosion of the Hoffman elbow occurred in 4 out of the 18 eyes that did not have a donor scleral patch graft (22%). No retinal detachment was recorded in this series. Conclusion:Successful IOP control shown in this series is in keeping with other published studies of this technique, which range from 64–95%. The rate of erosion of the plate portion of the Hoffman elbow was much higher (22%) than would be expected with other GDD when a scleral patch is not used. Despite these findings, this type of implant offers good IOP control in intractable glaucoma in those in whom anterior segment GDD placement is impractical.

Keywords: intraocular pressure