[Drainage systems in glaucoma surgery].
Glaucoma drainage devices, also known as aqueous shunts (AS) are widely used in the USA. They consist of a silicone tube that is inserted into the anterior chamber and connected to a plate made of silicone or polypropylene, the explant. The latter is positioned between the recti muscles and over several weeks the surrounding tissue forms a fibrous bleb around the plate. This serves as a permanent filtration reservoir.Recurrent failure of filtrating surgery is the main indication for the use of AS. Other indications include situations in which the formation of a filtering bleb seems to be unpromising because of extensive conjunctival scarring. Qualified success has been achieved for many years in 50-100% of the eyes treated depending on patient selection. The most serious complication is postoperative hypotonia that can lead to serious chorioidal detachment, suprachorioidal hemorrhage, flat anterior chamber and corneal decompensation. To avoid this complication some devices, i.e.the Ahmed Glaucoma and the Krupin valve have integrated mechanisms to sustain a residual intraocular pressure. With other devices i.e. the Molteno and the Baerveldt devices, the tube has to be temporarily ligated until bleb formation has started. On the other hand fibrous infiltration of the bleb 1-4 months after the surgery often leads to a reversible rise in introcular pressure, which can be treated by massaging the bulbus, needling the bleb or injection of antimetabolites. There are no obvious differences between the various forms of AS with regard to the success of pressure regulation. In summary,by close scrutiny of indications and management of complications,drainage systems are a useful option in the management of complicated glaucoma that carry a high risk of failure from conventional filtering surgery.
Hille
K
K
Universitäts-Augenklinik,Homburg/Saar, Germany.
Hille
A
A
Ruprecht
K W
KW
D004867:Equipment Design; D005901:Glaucoma / Q000601:surgery*; D020327:Glaucoma Drainage Implants; D006801:Humans; D011183:Postoperative Complications / Q000209:etiology; D012826:Silicone Elastomers
D012826:Silicone Elastomers