EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
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36 EW FEATURE February challenges/MIGS May 2013 Glaucoma 2011 Glaucoma surgery practice patterns changing by Erin L. Boyle EyeWorld Senior Staff Writer AT A GLANCE • A 2008 survey of AGS members found tube shunt use had grown since 1996. • The same 2008 survey found that trabeculectomy use had fallen. • Past Medicare data has shown that trabeculectomy use is declining. • MIGS could play a role in changing glaucoma surgical treatment practice patterns. With use of trabeculectomy and tube shunt surgery changing, surgical practice patterns appear to be shifting T he glaucoma surgical treatment paradigm has been shifting for a number of years, as surveys of physicians and Medicare data have shown, with trabeculectomy appearing not as popular as it once was, tubes slightly increasing in use, and microinvasive glaucoma surgery (MIGS) and ab externo procedures possibly gaining ground. The most recent published data on the use of trabeculectomy and tube shunts, specifically, is from 2008. Manishi A. Desai, MD, Department of Ophthalmology, Boston University School of Medicine and Boston Medical Center, and colleagues conducted an anonymous web-based survey of American Glau- coma Society (AGS) members that year, asking them for their preferred surgical approach in 10 clinical settings. Results were compared to findings from 1996 and 2002. From the 125 AGS members who responded to the survey, Dr. Desai and colleagues found that glaucoma drainage device use had increased from 17.5% in 1996 to 50.8% in 2008, while mean trabeculectomy use had decreased from 80.8% in 1996 to 45.5% in 2008. "Tubes are becoming a larger part of the physician armamentarium in the treatment of glaucoma," Dr. Desai said in an interview with EyeWorld. "In general, more physicians are becoming more comfortable with their use in treating glaucoma. I also feel it is becoming the surgery of choice for certain settings/types of glaucoma, especially neovascular glaucoma." Additional data Pradeep Y. Ramulu, MD, associate professor of ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, and colleagues published a paper in 2007 that examined Medicare data of glaucoma surgery from 1995 to 2004. In that time, they found that trabeculectomy in eyes without previous surgery or trauma decreased 53%, while the amount of aqueous shunting devices placed rose 184%. "If you look at more recent trends, tube shunts are still increasing, although maybe not as drastically as they did up until about 2007," Dr. Ramulu said. "If you look at trabeculectomy, it's been going down for many years, almost continuously for the last 10 or 15 years. The volume goes down almost every year. A little of this is because there's something besides tubes and trabeculectomy, there are other surgical procedures that are coming into the fold." "It's unclear whether some of these newer procedures are also taking away from trabeculectomy or to what extent people are choosing tubes instead of trabeculectomy, especially in more complicated cases, such as reoperations or operations for other types of glaucoma," he said. Before assuming that trabeculectomy is no longer as practiced as it once was, Garry P. Condon, MD, associate professor, College of Medicine, Drexel University, Pittsburgh, advised caution. He said there are multiple factors behind the increased use of tube shunts. Those include residents learning the procedure in training because it is less intrusive, and Medicare coding for modified trabeculectomy with use of the EX-PRESS Glaucoma Filtration Device (Alcon, Fort Worth, Texas) complicating the counting of trabeculectomy procedures performed. "What's really going on? I don't think we know. I think that a lot more new graduates are doing tubes than a decade ago. But with the established glaucoma people, I'm not convinced that's the case. On the other hand, with the established glaucoma people, a lot of them have converted many of their cases to the EX-PRESS device and we're seeing a drop in the trabeculectomy code because of that," he said. TVT study The Tube Versus Trabeculectomy (TVT) study, with its first results published in 2007, showed in a multicenter clinical trial that tube shunt surgery had maintained good IOP control and avoided many complications associated with trabeculectomy. Study first author Steven J. Gedde, MD, professor of ophthalmology, Bascom Palmer Eye Institute, Miami, said the TVT study enrolled patients who were less refractory than historically had undergone tube shunt surgery. "[The study] showed that both operations are very viable surgical options in patients with previous cataract and/or glaucoma surgery. I think that has supported a shift in practice patterns that was already occurring even before the published results of the TVT study," Dr. Gedde said. While bringing attention to tube shunts, the TVT study has also demonstrated that tubes can be as successful as trabeculectomy in certain cases, Dr. Desai said. However, the study also showed that tube shunt patients are typically on more drops during the first 2 years after surgery, and trabeculectomy can have great results with less medication needed immediately postoperatively. That difference is key for patients who need their pressure lowered with fewer related follow-ups visits, Dr. Condon said. Slit lamp photograph shows a tube implanted in a glaucomatous eye. Source: Manishi A. Desai, MD