Neil Canavan

March 21, 2012

March 21, 2012 (New York City) — Using the Trabectome (NeoMedix) surgical device to perform ab interno trabeculotomies significantly reduces intraocular pressure (IOP), according to a study presented here at the American Glaucoma Society 22nd Annual Meeting.

"We found a significant reduction in IOP and in the use of glaucoma medications up to 2 years after trabeculotomy surgery," said Yachna Ahuja, MD, from the Mayo Clinic in Rochester, New York.

The Trabectome device was approved by the US Food and Drug Administration in April 2004 and first used in the United States in January 2006. However, there are gaps in the clinical data regarding its use. "Compounding this issue, comparison with other glaucoma trials is problematic because of the different definitions used for success or failure of treatment," said Dr. Ahuja.

The objective of this retrospective study was to determine the success rate at a single center and to identify risk factors for the failure of the Trabectome ab interno trabeculotomy procedure.

Inclusion criteria for study enrollment included surgery from September 2006 to December 2010 and refractory primary open-angle glaucoma (POAG) or cataract surgery in the setting of open-angle glaucoma with or without previous glaucoma surgery. Exclusion criteria were fewer than 3 months of postoperative follow-up and previous retina or cornea procedures.

Dr. Ahuja and colleagues reviewed 246 patient charts. Of these, 158 patients had undergone combined trabeculotomy plus cataract extraction and 88 had undergone trabeculotomy only. Median age was 73 years, 95% of the patients were white, and 72% were women. The majority of patients were being treated for POAG (56%) or pseudoexfoliative glaucoma (26%).

After surgery, mean IOP dropped by 35%, compared with baseline. "This difference remained significant up to 2.5 years postsurgery (< .05)," said Dr. Ahuja.

Mean use of glaucoma medications dropped by 35%, and this improvement was maintained to 3.5 years (< .05).

According to the less-stringent criteria of success defined by the researchers — IOP level of 21 mm Hg or lower after the procedure or a 20% reduction in IOP from baseline — 64% of procedures were deemed successful at 1 year, dropping to 58% by year 3. In a subanalysis, the success rate at 3 years was higher for combined trabeculotomy plus cataract removal than for trabeculotomy alone (71% vs 33%; < .01).

For the more-stringent criteria — IOP level of 18 mm Hg or lower after the procedure or a 20% reduction in IOP from baseline — "there was a much lower success rate — 28% at 1 year and 18% at 3 years," Dr. Ahuja reported. There was no significant difference between groups in the subanalysis.

Of the 246 patients, 65 (26.4%) required a second surgery. Mean time to the second procedure was 10 months.

Emerging risk factors for treatment failure according to the more-stringent criteria were POAG (hazard ratio [HR], 3.14), previous argon laser trabeculoplasty (HR, 1.81), and myopia (HR, 1.10). Interestingly, pseudoexfoliation played a protective role [HR, 0.43]," Dr. Ahuja said.

"These data suggest that ab interno trabeculotomy with the Trabectome is a reasonable option for patients with mild glaucoma. I would recommend it for patients with high preoperative IOP, target IOPs of greater than 21, or when only a modest IOP reduction is required."

According to Marc Lieberman, MD, clinical professor of ophthalmology at the University of California, San Francisco, and owner of Glaucoma Consultants of the Bay Area, there is a disease in contemporary medicine in which "people think that because it's new and fancy it has some preordained merit. This drives people to try out these new very expensive toys and to sometimes lose sight of the more important things, like how to reach people who really need care."

"Why doesn't anybody just compare this electrical version of a surgical technique to standard goniotomy?" Dr. Lieberman asked. "If they had done that, it would have shown that [the Trabectome] may not have much additional merit."

"The Trabectome results that I have seen are very modest by all expectations, and the longer they go out [in follow-up], the alleged 20% reduction may not be particularly significant," said Dr. Lieberman.

Dr. Ahuja and Dr. Lieberman have disclosed no relevant financial relationships.

American Glaucoma Society 22nd Annual Meeting: Abstract 5. Presented March 1, 2012.

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