Mini-glaucoma shunt viable option for difficult cases

August 1, 2005

Rockford, IL—A glaucoma shunt that is relatively new to the market is getting very good results in patients whose IOP is uncontrolled despite multiple medications and glaucoma filtering surgeries. The Express Mini-Glaucoma Shunt (Optonol Ltd.) has thus far exceeded the expectations of Edward Yavitz, MD, who said that device is his shunt of choice.

Rockford, IL-A glaucoma shunt that is relatively new to the market is getting very good results in patients whose IOP is uncontrolled despite multiple medications and glaucoma filtering surgeries. The Express Mini-Glaucoma Shunt (Optonol Ltd.) has thus far exceeded the expectations of Edward Yavitz, MD, who said that device is his shunt of choice.

"I have used the Ahmed shunt [Ahmed Glaucoma Valve Implant, New World Medical Inc.], and it requires a much more extensive surgery," said Dr. Yavitz, assistant clinical professor, department of ophthalmology, University of Illinois College of Medicine, Rockford, IL. "In addition, surgery to implant the Ahmed shunt is longer compared with the mini-shunt. This surgery is also less invasive and shorter than a filtering surgery."

The surgery to implant the mini-shunt can be done in conjunction with a cataract procedure without the need to enlarge the incision a great deal and it requires less conjunctival and sub-Tenon's exposure, Dr. Yavitz explained.

To date, Dr. Yavitz has used the mini-shunt to treat six patients and has had "spectacular" results in two of the patients. Both had been taking multiple medications and had undergone failed trabeculectomies and failed trabeculoplasties.

"With the mini-shunt, not only did their IOP return to the normal range quickly after the surgery without the development of hypotony, but also the visual acuity improved by two lines, which I can't completely explain," he said.

He suggested that perhaps the visual acuity improvement occurred because there was no traumatic period of hypotony associated with the surgery, which normally occurs with trabeculectomy. The other four patients also had a very good postoperative course with normalization of their IOP in the range of 12 to 15 mm Hg. The blebs were very thin-walled and small compared with those associated with trabeculectomies and the corneas were quiet, he commented.

Dr. Yavitz presently uses the mini-shunt in patients whose condition has been refractory to both medical and surgical glaucoma treatments. However, he is considering using the device as a first-line treatment approach.

"Based on my initial successes, I am very tempted to use the mini-shunt as a first-line procedure for patients whose glaucoma is not controlled with drops alone," Dr. Yavitz said. "The device appears to be sufficiently safe and the surgery is easy to perform, so that any patient who is taking multiple anti-glaucoma medications would be a candidate for the shunt.

"I am starting to offer it to any patient who wants it," he said. "This device has changed my outlook on when to use a shunt procedure, because it is not difficult or dangerous in terms of postoperative complications."

One apparent drawback to the steel mini-shunt seems to be its size: 3 mm long and 400 μm in diameter. Initially, Dr. Yavitz said it was difficult to disassemble and reassemble the device without dropping it, even when using a fine forceps. The manufacturer has recently introduced a sleeve that covers the shunt that allows the surgeon to push the shunt off of its holder.

"It is a good idea to lubricate the shunt holder and place the shunt back on its holder 180° from the initial orientation," Dr. Yavitz said. "In this way, the shunt does not reattach itself as firmly to the holder and it can be implanted more easily. This is a trick I learned to ensure that the device would come off of its holder. Once it is inserted into the eye, a fish-hook-type barb holds it in place and this procedure eliminates any struggle with the device.