Novel membrane-tube type glaucoma shunt device for glaucoma surgery

Background: The background of this study is to introduce the surgical technique and outcomes of a novel membrane-tube (MT) type glaucoma shunt device (MicroMT), which was developed to achieve safer and more predictable intraocular pressure (IOP) control compared with conventional trabeculectomy. Design: This is a retrospective, non-comparative, interventional case series study. Participants: The MicroMT was implanted in 43 glaucomatous eyes with insufficient IOP control despite medical treatment. Methods: The MicroMT consists of an expanded polytetrafluoroethylene membrane and a silicone tube with an intraluminal stent, which allows aqueous drainage from the anterior chamber to the lamellar scleral flap. The intraluminal stent prevents excessive aqueous drainage and allows additional IOP reduction through retraction or removal of the stent. Main Outcome Measures: The main outcome measures of this study are IOP changes and complications. Results: The mean (SD) IOP decreased from a preoperative value of 22.5 (6.9) mmHg to 11.1 (3.6) mmHg 3 years after the operation (50.7% reduction from baseline; P<0.01). Intraluminal stent removal 4 weeks after the operation induced an additional 40.2% IOP reduction (P<0.01). When success was defined as an IOP between 6 and 21 mmHg, and an IOP reduction of >= 20% from baseline, the success rate was 89.5% at 3 years after the operation. No postoperative ocular hypotony (IOP <6 mmHg) or tube-related complications occurred. Conclusions: MicroMT implantation is a novel therapy that may reduce IOP safely and effectively, with no apparent risk of postoperative ocular hypotony. Glaucoma surgery using this device may be a good alternative to conventional glaucoma surgery.