Eyeworld

EW GLAUCOMA 76 by Faith A. Hayden EyeWorld Staff Writer An update on canaloplasty Encouraging long-term data indicates procedure is here to stay W ith every new proce- dure, novel tech- nique, and device invention, doctors go through the same choreographed dance in three dis- tinct parts. First comes skepticism, where surgeons watch and wait. Will the new technique prove safe and effective? Then come the practical considerations, where physicians ask if a procedure is right for their prac- tice. Will their patient population support a need for the technique? Full integration is the final step in the often years-long tango, with the question morphing from "Should I?" to "How do I?" Canaloplasty, a non-penetrating and minimally invasive procedure for open-angle glaucoma, is cur- rently traversing that journey. If the 3-year safety and efficacy study re- sults are any indication, the initial phase is passing. "A couple of years ago, there was still a healthy amount of skepti- cism" surrounding canaloplasty, said Robert Noecker, M.D., vice chair, ophthalmology department, Univer- sity of Pittsburgh Medical Center Eye Center. "We've moved beyond that. There's been data published, and it's been recommended by qual- ity surgeons who have had good re- sults." Richard A. Lewis, M.D., cataract surgeon and glaucoma spe- cialist, Sacramento, Calif., and col- leagues published the most recent data in the April issue of the Journal of Cataract & Refractive Surgery (2011; 37:682-690). "Canaloplasty led to significant and sustained IOP reduction in adult patients with open-angle glaucoma and had an excellent short- and long-term postoperative safety pro- file," the researchers wrote. Complications in the 157 eyes studied were infrequent. Early prob- lems included a 12.1% incidence of microhyphema and a 0.6% occur- rence of hypotony. Four blebs, or 2.5% of eyes, occurred at 36 months, but no long-term bleb-related diffi- culties were observed. The mean IOP for study eyes was 15.2. "The long-term results were very good," said Dr. Lewis. "Studies are continuing, and there will probably be a 5-year paper." An intimidating procedure Despite promising patient outcomes, many surgeons are hesitant to add canaloplasty to their armamentar- ium. Both Drs. Lewis and Noecker believe that the reluctance is prima- rily due to unfamiliarity with the anatomy of Schlemm's canal. "Canaloplasty isn't as simple as a trabeculectomy where you just have to make a hole," explained Dr. Lewis. "In this case, you have to re- ally know where the anatomy is and carefully dissect down into it. It's about getting to that comfort level of knowing you can dissect into a certain spot." Dr. Lewis advised that canal ac- cess is deeper down than antici- pated, and there are certain anatomical cues a surgeon can look for to help with orientation. "The sclera is white and the cornea has a blue-gray look to it," he said. "In the transition between that, the scleral fibers begin to have more of a horizontal orientation. When you see the change, you know you're either into or next to the canal." One challenge Dr. Noecker men- tioned was suturing the end of the microcatheter. Surgeons don't sew much anymore, so to prepare for canaloplasty, he recommended brushing up on suturing skills. A web lab could also be beneficial for the surgeon and the staff. Dr. Noecker estimated it would take five cases for a beginner to become effi- cient at canaloplasty and 10 cases to hit a stride. "The more you do it, the easier it gets," he said. "You do have to pay attention to detail. There are multi- ple steps you have to learn. None of them are particularly difficult or unique. We've all done parts of the procedure within other procedures. It's just never been packaged into one." Another challenge physicians encounter is difficulty passing the catheter, which can become blocked by a valve in the canal or by scarring from a previous surgery. The trick, said Dr. Lewis, is to pull out and go in the other direction. "Because it's a 360-degree sys- tem, you can go left or right," he said. "You can manipulate an area where there's a blockage. There are a number of little tricks you can do to facilitate the passage of the catheter. You can dilate with viscoelastic and try to enlarge [the canal] and pass the catheter through." Proper patient population Surgeons often wonder if canalo- plasty is right for their patient popu- lation. According to Dr. Noecker, more patients qualify for the proce- dure than is initially obvious. "The practitioners who are high- volume cataract, just by default with the demographics, are taking care of February 2011 September 2011 A lthough there are many new glaucoma innovations on the horizon, one of the first to be available in the U.S. is canaloplasty— the focus of this Corner of the world. To perform a canaloplasty, the surgeon first finds Schlemm's canal and then uses a very elegant cannula to place a 9-0 su- ture. The suture ends are tied together and this keeps the entire inner wall of the canal under tension. The goal of the procedure is internal drainage of aque- ous rather than external drainage through a bleb. The procedure has been studied in multiple case series both in the U.S. and in Europe. The results have been very impressive—pressures in the mid-teens with very few complications and no blebs. The barriers to performing it are mainly technical—finding Schlemm's canal and manipulating the cannula and fine sutures. We are very fortunate to have Rick Lewis, M.D., and Rob Noecker, M.D., who both have ex- tensive credentials with canaloplasty and other innovative procedures, giving us their insights into this exciting new procedure. Canaloplasty is potentially a breakthrough glaucoma procedure. Sur- geons wanting to avoid the complica- tions of trabeculectomy will be moving more and more to canaloplasty. Reay Brown, M.D., glaucoma editor Glaucoma editor's corner of the world A gonioscopic view of the tensioning suture left in the canal of Schlemm to increase outflow through the trabecular meshwork Source: Robert Noecker, M.D.

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