Gold shunt shines in study of patients with POAG

September 1, 2008

Implantation of a glaucoma drainage device made entirely from medical-grade gold (SOLX GMS Plus Gold Shunt, SOLX Inc.) is a viable surgical option for primary open-angle glaucoma (POAG).

Key Points

Chicago-Implantation of a glaucoma drainage device made entirely from medical-grade gold (SOLX GMS Plus Gold Shunt, SOLX Inc.) is a viable surgical option for primary open-angle glaucoma (POAG). It reduces IOP, decreases the number of medications patients need, leaves no filtering bleb, and has a low rate of complications, according to Gabriel Simon, MD, PhD, speaking here at the annual meeting of the American Society of Cataract and Refractive Surgery.

The gold shunt is designed to reduce IOP by establishing flow through the device from the anterior chamber to the suprachoroidal space. No filtering bleb is created. The shunt is 5.21 mm long, 2.4 mm wide at the "head" end, and 3.2 mm wide at the "tail" end. It is 68 µm thick, 40 µm high, and 25 µm wide.

Dr. Simon, of the Instituto Oftalmologia, Madrid, Spain, and colleagues implanted the gold shunt in 82 eyes at two centers in Spain and one in Israel. The 82 patients in this study all had a diagnosis of POAG, their conditions had failed to respond to maximally tolerated medications, and they had a suitable quadrant for shunt implantation. The patients' mean age was 67.5 ± 11.3 years. Fifty-seven percent of the patients were female, 73% were pseudophakic, 18% were phakic, and 9% were aphakic. Most of the patients (64%) had undergone prior intraocular surgery, and 47% had a prior failed trabeculectomy.

Acute mild hyphema (<3 mm Hg) was the most common complication seen (in 32 [39%] patients), but in all cases, the hyphema had resolved by the 1-week follow-up. Grade 1 or 2 AC cells or flare were reported in about one-fourth of the patients; it typically resolved within 3 days. Nine percent reported Grade 1 or 2 pain that did not require treatment.

Less common complications included shunt-cornea touch (4% of patients), shunt-iris touch (1%), transient hypotony (1%), iritis (1%), and infection (1%).

"[Shunt] implantation is a viable surgical option for the treatment of POAG," Dr. Simon said. "Mean IOP fell into the mid teens immediately after surgery from an average of almost 28 mm Hg at baseline, then stabilized at about a 33% reduction in at 12 months, and there was a concomitant decrease, by about one-half, in the number of medications used."

Implantation

The technique to implant the shunt is relatively straightforward, he said:

• The implant is installed at an angle into the suprachoroidal space. First, a 4 X 4-mm conjunctival flap is prepared, followed by a 3-mm incision cut to the depth of 90% of the sclera.

"This is important because you're going to make a cut all the way into the suprachoroidal space later in the procedure," Dr. Simon said.

•A tunneling incision then is made, usually with a 3.2-mm blade, anteriorly into the angle.

"You're trying to maintain a very thin scleral shelf underneath this cut," he said.

•The full-thickness incision then is made into the suprachoroidal space directly below the original incision.

"You can verify the entry into the suprachoroidal space with a cyclodialysis spatula, which should move freely in the space at this time," Dr. Simon said.

•The shunt then is introduced into the incision, forward into the angle.

•The tail end of the shunt then is pulled backward into the opening made in the suprachoroidal space. This can be done with a needle tip or with a paracentesis needle from the other side to push the shunt.

•The scleral incision then is sutured closed watertight.

•The conjunctiva is closed separately after final positioning to ensure that the tip of the shunt is placed deep in the angle.

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