EyeWorld Asia-Pacific September 2017 Issue

September 2017 EWAP SECONDARY FEATURE 27 XEN Gel Stent: When to use and how to implant AT A GLANCE r 5IF 9&/ (FM 4UFOU JT JNQMBOUFE XJUI POF FOE JO UIF BOUFSJPS DIBNCFS BOE UIF PUIFS JO UIF TVCDPOKVODUJWBM TQBDF GPS BC JOUFSOP CMFC GPSNBUJPO r 5IF NN QPSDJOF HFM NBUFSJBM DSPTTMJOLFE XJUI HMVUBSBMEFIZEF çN JO EJBNFUFS CFDPNFT áFYJCMF XIFO JOTFSUFE JO UIF FZF r 1IZTJDJBOT SFQPSU B TUSPOH TBGFUZ BOE FGàDBDZ QSPàMF JO B WBSJFUZ PG TJUVBUJPOT “Hybrid” MIGS device launches in U.S. market O ptions—that’s what many physicians say the XEN45 Gel Stent (Al- lergan, Dublin, Ireland), one of the latest implants to join the market of surgical glaucoma procedures, gives them. Joseph Panarelli, MD , as- sistant professor, Department of Ophthalmology, 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, Depart- ment of Ophthalmology, New York University 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 , as- sistant professor of ophthalmology and visual sciences, Washington by Liz Hillman EyeWorld Staff Writer University School of Medicine, St. Louis, discussed the XEN as a “hybrid” between microinvasive glaucoma surgery (MIGS) and tradi- tional glaucoma 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 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 immediately in the [subcon- junctival] 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 crosslinked 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- 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. Shey- bani said. Patient selection Per on-label uses, the XEN is indicated for refractory glaucoma patients with failed previous surgi- cal treatment and for patients with primary open-angle glaucoma (POAG) or those with pseudoexfoli- ative 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. 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 predictable that I prefer it for even earlier intervention because those are the eyes where you would hate to take someone with good vi- sion and minimal field loss but high pressures, you would hate to subject them to the aggressive surgery … but in this case, we have an opera- tion that seems to have less risk.” Dr. Sheybani said he would use it in angle closure and pediatric cases, which are also considered off-label. Dr. Radcliffe has used the XEN in a number of different scenarios, but his favorite candidate is a young, phakic individual with ex- cellent vision. “A 24-year-old patient of mine had juvenile primary open-angle glaucoma, and his pressures were 40 mmHg on all of the medications. I did XEN Gel Stents in both eyes, and he’s now off all of his drops with pressures of 8,” Dr. Radcliffe said. “That’s an ideal scenario, but now he’s going to have a life with 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 continued on page 28