접수번호:07-081 Korean Journal of Ophthalmology 2009;23:86-92 ISSN : 1011-8942 DOI : 10.3341/kjo.2009.23.2.86 Clinical Outcomes of Ahmed Glaucoma Valve Implantation Using Tube Ligation and Removable External Stents Jong Joo Lee, MD1, Ki Ho Park, MD, PhD1, Dong Myung Kim, MD, PhD1, Tae Woo Kim, MD, PhD2 1Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea 2Department of Ophthalmology, Seoul National University Bundang Hospital, Seongnam, Korea Purpose: To investigate the immediate and long-term outcomes of Ahmed glaucoma valve (AGV) implantation with silicone tube ligation and removable external stents. Methods: This retrospective non-comparative study investigated the outcomes of AGV implantation with silicone tube ligation and removable external stents in 95 eyes (90 patients) with at least 12 months of postoperative follow-up. Qualified success was defined as an intraocular pressure (IOP) of ≤21 mmHg and ≥6 mmHg regardless of anti-glaucoma medication. Those who required additional glaucoma surgery, implant removal or who had phthisis bulbi were considered failures. Hypotony was defined as an IOP of <6 mmHg. Results: Mean IOP reduced from 37.1±9.7 mmHg preoperatively to 15.2±5.6 mmHg at 12 months postoperatively (p<0.001). Qualified success was achieved in 84.2% at 1 year. Hypotony with an IOP of <6 mmHg was seen in 8.4% and an IOP of <5 mmHg in 3.2% on the first postoperative day. No case of hypotony required surgical intervention. Suprachoroidal hemorrhage did not occur in this study. When stents were removed on the first post- operative day because of an insufficient IOP decrease, the mean IOP decreased significantly from 42.0 mmHg to 14.1 mmHg (p<0.001) after 1 hour. The most common complication was hyphema, which occurred in 17.9%. Conclusions: Hypotony-related early complications requiring surgical intervention were reduced by ligation and external stents in the tube. In addition, early postoperative high IOPs were managed by removing external stents. The described method can prevent postoperative hypotony after AGV implantation and showed long-term success rates comparable to those reported previously. Korean J Ophthalmol 2009;23:86-92 ⓒ 2009 by the Korean Ophthalmological Society. Key Words: Ahmed glaucoma valve, External stents, Tube ligation Glaucoma drainage devices are generally used to control intraocular pressure (IOP) in refractory glaucoma1 and can lower IOP by allowing aqueous humor to be drained to an extrascleral reservoir through a small-caliber tube. Earlier glaucoma drainage devices have low resistance to aqueous outflow and cause hypotony during the immediate postope- rative period until a fibrous capsule develops around the extrascleral plate.2-4 To overcome early postoperative hypotony and its attendant complications, valved implants have been developed, which are designed to restrict excessive aqueous drainage. The Ahmed glaucoma valve (AGV) implant (New World Medical, Inc. Rancho Cucamonga, LA, USA) is a valved implant that was approved by the United States Food and Drug Administration in Received: December 7, 2007 Accepted: March 24, 2009 Reprint requests to Ki Ho Park, MD, PhD. Department of Ophthalmology, Seoul National University Hospital, #28 Yeongeon-dong, Jongno-gu, Seoul 110-744, Korea. Tel: 82-2-2072-2438, Fax: 82-2-741-3187, E-mail: kihopark@ snu.ac.kr * The contents in this paper were presented in the 94th Annual Meeting of the Korean Ophthalmological Society in Seoul on October 7, 2005. 86 1993.5 The AGV implant is designed to open when the IOP is between 8 mmHg and 10 mmHg, and thus maintains an IOP of 8 mmHg or higher.5-7 Moreover, AGV implantation showed a lower incidence of postoperative hypotony than non-valved glaucoma drainage device implantation, but the clinical problem of postoperative hypotony was not resolved by valved glaucoma drainage devices.5,8-12 Previous in vitro tests have shown that valved implants may not completely close after initial perfusion with fluid, and that they may function as flow-restricting devices without demonstrable opening or closing pressures.6,7 Partial ligation of the AGV tube has been attempted to lower early postoperative hypotony and its surgical complications.13,14 Here, we describe the use of a ligated silicone tube with external stents in AGV implant surgery. The tube ligation was considered to restrict flow from the anterior chamber. External stents were added to be easily removed in cases of high IOP during the early postoperative period before the ligated suture was absorbed. In this study we aimed to in- vestigate the immediate and long-term outcomes, in terms of IOP and complications, in AGV implantation using tube ligation and external stents.