Eyeworld

EW FEATURE 77 Alternatives to trabeculectomy may better suit specific patients and clinical goals than that long-dominant procedure A s growing numbers of new devices and surgical procedures for treating various forms of glau- coma continue to emerge, surgeons are increasingly favoring alternatives to the long-dominant trabeculectomy procedure. Although not all of the newer approaches have received FDA ap- proval, both approved and as-yet unapproved approaches may better serve specific patients and individual clinical goals than trabeculectomy, according to some surgeons. These emerging technologies and approaches "will give us a greater ability to individualize in- stead of using a single gold stan- dard," said Douglas J. Rhee, M.D., assistant professor, Massachusetts Eye and Ear Infirmary, Harvard Med- ical School, Boston. "There is not one single procedure out there that is going to supplant trabeculectomy for all of the scenarios in which one might find himself; however, there are many clinical scenarios where some of these new procedures are the same or superior to trabeculec- tomy. We're moving away from the gold standard concept." Richard A. Lewis, M.D., Sacra- mento, Calif., also sees the glaucoma surgery field broadening beyond tra- beculectomy. "Instead of essentially one ham- mer [i.e., trabeculectomy] for almost everything, we are beginning to cus- tomize the treatment and, more im- portantly, now have procedures that have or will have fewer complica- tions," Dr. Lewis said. Among the newer approaches that have received FDA approval and yield better clinical outcomes for some patients is the ab interno Trabectome (Neomedix, Tustin, Calif.). The thermal cautery device, which ablates the trabecular mesh- work and Schlemm's canal for about 3-5 clock hours through a temporal clear corneal incision, may best suit patients also undergo- ing cataract surgery. Dr. Rhee noted that repeated studies have shown that Trabectome treatments provided in conjunction with cataract surgery are about as ef- fective as cataracts done in conjunc- tion with trabeculectomy, although neither approach is as effective as trabeculectomy performed alone. The Trabectome combined surgical approach has the advantage of gen- erally fewer complications than tra- beculectomy. The Trabectome combined ap- proach, Dr. Rhee said, best fits open- angle glaucoma patients who need modest pressure lowering, as well as patients who do not need pressure lowering but want to minimize the risk of a post-cataract IOP spike. The use of the Trabectome ap- proach also allows surgeons to per- form a subsequent trabeculectomy if the initial device fails, Dr. Rhee and his associates found in a soon-to-be- published study. "Nothing is risk free, but the Trabectome has a relatively low complication rate," Dr. Rhee said. "The selection of patients is a little more limited because of the limited effectiveness profile." Such ab interno approaches "are very exciting," Dr. Lewis said. "They are less traumatic to the eye—and conjunctiva—safer, and faster." Another surgical option that may benefit some patients better than trabeculectomy is the iStent (Glaukos, Laguna Hills, Calif.). Al- though this snorkel-like device had not yet received FDA approval as of late December, research indicates that it provides better IOP control when combined with cataract sur- gery than trabeculectomy combined with cataract removal, as well as lower complication rates, Dr. Rhee noted. The iStent "offers a very safe clear corneal approach to placement of a tiny transtrabecular stent," said Louis B. Cantor, M.D., chairman and professor of ophthalmology, Eu- gene and Marilyn Glick Eye Institute, Indiana University School of Medi- cine, Indianapolis. "If this device is able to achieve good IOP reduction, it offers an advantage over many of our more invasive or complex proce- dures." Stand-alone option Alternatively, early stage or mild open-angle glaucoma patients who do not need cataract surgery and don't want a trabeculectomy may benefit from canaloplasty, said Dr. Rhee. The procedure also suits pa- tients whose glaucoma has advanced to the point where the physician is concerned that dynamic anterior chamber changes during a tra- beculectomy procedure (repeated flattening and refilling of the ante- rior chamber) could endanger the optic nerve. Dr. Cantor noted that a canalo- plasty is "technically challenging" but is effective in enhancing the tra- becular outflow while avoiding the creation of a filtering bleb on the eye. "I believe that the next genera- tion of glaucoma surgery should strive to control IOP without creat- ing a bleb, as bleb-associated compli- cations are the Achilles' heel of standard glaucoma filtering surgery today." The external approach of canaloplasty uses a dissection down to Schlemm's canal, where a catheter is threaded through. The procedure aims to leave a dilated canal, left under tension by a 10-0 prolene su- ture, along with an internal scleral lake that functions as an internal bleb. Although no head-to-head com- parisons have been conducted be- tween canaloplasty and the Trabectome, Dr. Rhee noted that canaloplasty's "success profile" is su- perior to that reported for the Tra- bectome. Research indicates that a failed canaloplasty would reduce the abil- ity to perform a subsequent tra- beculectomy, Dr. Rhee said. Subsequent surgical treatment with a tube device is recommended. "Canaloplasty and the Trabec- tome procedure are mutually exclu- sive," Dr. Rhee said. "Once you do one, you cannot do the other." However, effective trabeculec- tomies are still possible in the cases of failed Trabectomes and iStents. Patients with refractory glau- coma also have the option of an en- dolaser cyclophotocoagulation procedure. Additionally, Dr. Rhee noted the endolaser camera can pro- vide "significant help" when per- forming other procedures. The de- vice generally has the same risks and patient profile as the Trabectome. "If I have a patient in whom I am doing a cataract extraction and I want a little more pressure lowering then I will add an endolaser," Dr. Rhee said. Trabeculectomy add-on Patients who receive a trabeculec- tomy may benefit from the addition of an EX-PRESS Glaucoma Filtration Device (Alcon, Fort Worth, Texas). The transcleral procedure moves be- yond traditional trabeculectomies by offering internal resistance to poten- tially reduce hypotony-related com- plications. "The disadvantage is that it is made of stainless steel so the long- term issues may be problematic," Dr. Rhee said. "Also, there is an addi- tional cost and the additional bene- fit is modest." Ongoing research is expected to help further clarify which patients and conditions will most benefit from each of these procedures. How- ever, none of them are expected to supplant trabeculectomy for all pro- cedures. "Given the long-term complica- tions of trabeculectomy and the high peri-operative complication rates in comparison to these new de- vices, we need to move away from this gold standard concept and start to adopt the concept of utilizing spe- cific devices and procedures for the management of individual condi- tions, patients, and scenarios," Dr. Rhee said. EW Editors' note: Dr. Cantor was an inves- tigator for Glaukos and iScience (Menlo Park, Calif.), and he has financial in- terests with Abbott Medical Optics (Santa Ana, Calif.). Dr. Lewis has fi- nancial interests with Alcon, AqueSys (Irvine, Calif.), Glaukos, iScience, Ivan- tis (Irvine, Calif.), and Transcend Med- ical (Menlo Park, Calif.). Dr. Rhee has no financial interests related to his comments. Contact information Cantor: 317-274-8485, lcantor@iupui.edu Lewis: 916-649-1515, rlewiseyemd@yahoo.com Rhee: 617-573-3670, douglas_rhee@meei.harvard.edu February 2011 February 2011 GLAUCOMA What are your fellow surgeons talking about today? Are you missing out on something new? Need a quick answer or consultation? Got a suggestion for a fellow surgeon? Just want to stay in the loop? Subscribe to ASCRS's eyeCONNECT today and connect with colleagues in a worldwide virtual community. Visit www.EyeSpaceMD.org and click the eyeCONNECT tab. Login (it's the same as logging in on the ASCRS website) Click "My Subscriptions" Choose the list(s) you wish to subscribe to, the delivery method, and click "save." Not yet a member of ASCRS? Visit www.ASCRS.org and join online today. Click the "Membership" tab. Discussions are taking place right now on ASCRS' eyeCONNECT — one of ASCRS' most popular member benefits. Ask questions, help others, or just follow the engaging discussions from around the world. But don't be left out! Here's what members say about eyeCONNECT: "It provides instantaneous feedback that benefits my patients." Warren E. Hill, MD, FACS "There is simply no better way for tapping into the expertise of my colleagues." Uday Devgan, MD "It's like having grand rounds with ophthalmology's best thinkers." W. Lee Wan, MD "There's not an ophthalmologist in the world that won't learn from this forum." Richard L. Lindstrom, MD EWAD4 by Rich Daly EyeWorld Contributing Editor Moving beyond the "gold standard" for glaucoma 58-81 Feature_EW February 2011-DL2_Layout 1 2/4/11 2:31 PM Page 77

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