48 EyeWorld Asia-Pacific | December 2024 Obstacle #5: Low-teens target Dr. Li said that while she can’t count on a consistent, lowteens target with the XEN, she has had more success if she modifies the stent, cutting it to be a little shorter than its original 6 mm. “By decreasing the length of the tube, it decreases resistance and increases the flow rate to achieve a lower IOP,” she said. “The sub-Tenon’s portion is also a little shorter so potentially you’ll have less length to be embedded into Tenon’s.” Obstacle #6: XEN failure Dr. Yohannan said a lot of avoiding XEN failure comes down to good intraoperative technique. If you’re placing it sub-Tenon’s, there’s not much you can do if it starts failing postop because it’s hard to needle in that position, and it’s a flimsy stent. “It’s going to be hard to separate that thick tissue from the stent, whereas when you’re subconjunctival, it’s a little easier because there’s not thick tissue over it,” he said. “I think the main thing is ensuring you control inflammation. About the Physicians Ang Li, MD | Assistant Professor of Ophthalmology, Case Western Research School of Medicine, Cleveland Clinic Cole Eye Institute, Cleveland, Ohio | lia2@ccf.org Jithin Yohannan, MD | Boone-Pickens Assistant Professor of Ophthalmology, Johns Hopkins University School of Medicine, Wilmer Eye Institute, Baltimore, Maryland | jyohann1@jhmi.edu Relevant Disclosures Li: MicroSurgical Technology, New World Medical, Nova Eye Medical Yohannan: AbbVie, Alcon References 1. El Helwe H, et al. Comparing outcomes of 45 Xen implantation ab interno with closed conjunctiva to ab externo with open conjunctiva approaches. J Glaucoma. 2024;33:116–125. 2. Tan NE, et al. Comparison of safety and efficacy between ab interno and ab externo approaches to Xen Gel Stent placement. Clin Ophthalmol. 2021;15:299–305. 3. Yuan L, et al. Short-term outcomes of Xen-45 Gel Stent ab interno versus ab externo transconjunctival approaches. J Glaucoma. 2023;32:e71–79. 4. Ruda RC, et al. Clinical outcomes of ab interno placement versus ab externo placement of XEN45 Gel Stents. Ophthalmol Glaucoma. 2023;6:4–10. This article originally appeared in the September 2024 issue of EyeWorld. It has been slightly modified and appears here with permission from the ASCRS Ophthalmic Services Corp. I’ll do steroids every 2 hours for a week. … If you have an occlusion of the proximal lumen from the iris, sometimes doing a YAG to the tip may be helpful. Even if there is no occlusion from the iris and the IOPs begin to go up, a YAG to the tip in the AC to shorten the overall length of the XEN may be helpful to increase flow and reduce IOP. In my experience, needling does not work well when the stent fails after the sub-Tenon’s approach. Most of the time, it works well with a great bleb morphology in the right patient, and you’re not subjecting them to in-office needlings.” If the XEN fails despite these efforts, Dr. Yohannan said he’ll add back medications and see how the patient does. If they remain uncontrolled, he’ll do a trab next to the XEN. “By scarring the XEN, they’ve shown me that they’re able to fibrose well. They’re probably not going to become hypotonous after trab,” he said. Since its inception, Dr. Li said many pearls have been learned overall, to overcome some of the initial hurdles with the XEN. “There are so many different ways of doing the XEN, which is exciting,” she explained. GLAUCOMA
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