Eyeworld

EW FEATURE 50 MIGS roundup • July 2017 AT A GLANCE • The XEN Gel Stent is implanted with one end in the anterior chamber and the other in the subconjunctival space for ab interno bleb formation. • The 6-mm porcine gel material crosslinked with glutaraldehyde, 45 µm in diameter, becomes flexible when inserted in the eye. • Physicians report a strong safety and efficacy profile in a variety of situations. by Liz Hillman EyeWorld Staff Writer Panarelli said he would consider it in ocular hypertension patients who are intolerant of medical therapy as well as those with mild to moderate glaucoma. Dr. Sheybani said, "For me, it's that the surgery is so predict- able that I prefer it for even earlier intervention because those are the eyes where you would hate to take someone with good vision and mini- mal field loss but high pressures, you would hate to subject them to the aggressive surgery … but in this case, we have an operation that seems to have less risk." Dr. Sheybani said he would use it in angle closure and pediatric cases, which are also con- sidered off-label. Dr. Radcliffe has used the XEN in a number of different scenarios, but his favorite candidate is a young, phakic individual with excellent vision. "A 24-year-old patient of mine had juvenile primary open-angle glaucoma, and his pressures were 40 tiva, erosion would be more com- mon, and the swelling is important because once it has been placed, it's not likely to move and fixes itself into position." The composition of the material itself also does not elicit a fibrotic response, Dr. Sheybani said. The procedure is creating a controlled wound in the eye, he explained, and the body naturally wants to cause fibrosis. Certain materials naturally elicit a fibrotic response, so having a material that doesn't is a theoretical advantage, Dr. Sheybani said. Patient selection Per on-label uses, the XEN is indicat- ed for refractory glaucoma patients with failed previous surgical treat- ment and for patients with primary open-angle glaucoma (POAG) or those with pseudoexfoliative or pigmentary glaucoma with open angles who are not responsive to the maximum medical therapy. However, some doctors consider off-label applications as well. Dr. not quite MIGS; it's not quite the higher risk glaucoma surgeries," Dr. Sheybani said. "The other reason I call it a hybrid is it's almost a hybrid of a trabeculectomy and a tube. It's a tube itself, but the flow starts im- mediately in the [subconjunctival] sub-Tenon's space, and we have to use mitomycin just like we do with our trabeculectomies." About the implant The XEN received approval from the U.S. Food and Drug Administra- tion (FDA) in November 2016 and launched in the U.S. in early 2017. The translimbal implant target- ing the subconjunctival space for ab interno bleb formation consists of a 6-mm porcine gel material cross- linked with glutaraldehyde, 45 µm in diameter, that swells and becomes flexible when implanted. "The advantages there are it will accommodate to the tissue and this should limit the erosion," Dr. Radcliffe explained. "If you had something rigid under the conjunc- "Hybrid" MIGS device launches in U.S. market O ptions—that's what many physicians say the XEN45 Gel Stent (Allergan, Dub- lin, Ireland), one of the latest implants to join the market of surgical glaucoma proce- dures, gives them. Joseph Panarelli, MD, assistant professor, Department of Oph- thalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, said he thinks the XEN has broad applications in a variety of patients. Nathan Radcliffe, MD, clinical assistant professor, Department of Ophthalmology, New York Univer- sity Langone Medical Center, New York, emphasized that XEN can be a standalone procedure or coupled with cataract surgery. It also leaves the option open for more aggressive glaucoma surgery, if needed, later down the line. Arsham Sheybani, MD, assis- tant professor of ophthalmology and visual sciences, Washington Univer- sity School of Medicine, St. Louis, discussed the XEN as a "hybrid" between microinvasive glaucoma surgery (MIGS) and traditional glau- coma surgery. "I say hybrid for two reasons. I think it is a hybrid between tradi- tional surgery and MIGS because it's minimally invasive, it's very controlled, but it also accesses the subconjunctival space route, which right now is our best way to lower pressure with a trab or a tube. It's XEN Gel Stent: When to use and how to implant continued on page 52 The Xen Gel Stent is inserted through a clear corneal incision with one end implanted in the subconjunctival space and the other in the anterior chamber to facilitate aqueous outflow for ab interno bleb formation. Source: Joseph Panarelli, MD

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