Systematic Occlusion of Shunts: Control of Early Postoperative IOP and Hypotony-related Complications Following Glaucoma Shunt Surgery

Abstract

Objective: Evaluation of a protocol of total intraluminal occlusion of Baerveldt shunts and its effects on early postoperative intraocular pressure (IOP) control and hypotony-related complications.

Design: This was a noncomparative, prospective, and interventional study.

Participants: Glaucoma patients were recruited to undergo Baerveldt shunt surgery. A total of 116 eyes of 112 patients were enrolled.

Intervention: During shunt implantation, aqueous outflow was restricted using an intraluminal occluding stent inserted through the entire tube length, with and without external ligation, to halt aqueous flow. Postoperatively, eyes underwent ligature laser suture lysis and partial or complete stent removals, at predetermined time intervals.

Main outcome measure: Loss of postoperative IOP control was categorized as transient or persistent hypotony (IOP≤5 mm Hg) or hypertony (IOP>21 mm Hg). Patients were followed up for 1 year.

Results: Preoperatively median IOP was 23 mm Hg (mean 26 mm Hg, SD 12 mm Hg), median number of glaucoma medications was 3.0 (mean 3.0, SD 1.2). During year 1, laser suture lysis was performed in 30 eyes (26%) and stent removal in 93 eyes (80%) (23 partial; 70 complete). There was 1 case of transient hypotony, no cases of persistent hypotony, 10 of transient hypertony, and 3 of persistent hypertony. Nine eyes had IOP≤5 mm Hg at ≥1 time points and hypotony-related complications occurred in 8 eyes (7%). At 1 year, median IOP was 12 mm Hg (mean 13 mm Hg, SD 4 mm Hg) with a median of 1.0 glaucoma medications (mean 1.1, SD 1.3). The cumulative probability of failure during the first 12 months follow-up was 6% (n=7). Overall postoperative complications occurred in 11 eyes (9%).

Conclusions: The surgical and postoperative protocol resulted in controlled, step-wise reductions of IOP with low rates of hypotony and related complications.