Ab Interno XEN Gel Stent Implantation in Eyes with Previous Tube Shunt Surgery

• Published in: Clinical ophthalmology (Auckland, N.Z.) N.Z.), 2022-09, Vol.16, p.3205-3212
• Main Authors: Xu, Lily Kai Man, Chan, Toby Yiu Bong
• Format: Article
• Language: English
• Subjects: ab interno xen implant; ahmed glaucoma valve; baerveldt glaucoma device; Cornea; Eye surgery; Glaucoma; Iodine; Medical research; Medicine, Experimental; migs; Ophthalmic drugs; Prisoners of war; Short Report; Stent (Surgery); Surgery; Transplants & implants; tube shunt; Viscoelasticity
• ISSN: 1177-5483; 1177-5467; 1177-5483
• DOI: 10.2147/OPTH.S378038

Purpose: After tube shunt surgery, many factors may contribute to insufficient filtration over time, prompting further intervention to achieve optimal intraocular pressure (IOP) control. This study explores whether ab interno XEN gel stent implantation could be a viable approach in eyes that need further IOP reduction after tube shunt surgery. Methods: This is a retrospective, single-surgeon case series on ab interno XEN45 gel stent implantation in eyes that had previous tube shunt surgery. Main outcome measures were IOP and number of glaucoma medications at the pre-operative visit, post-operative week (POW) 1, and post-operative month (POM) 1, 3, 6, and 12. Adverse events and further interventions were noted. Surgery outcome was qualified as absolute success (IOP [less than or equal to] 18mmHg or [greater than or equal to] 20% IOP reduction without glaucoma medications), qualified success (IOP < 18mmHg or [greater than or equal to] 20% IOP reduction with glaucoma medications), or failure (IOP > 18mmHg and < 20% IOP reduction with maximum tolerated glaucoma medications). Results: 7 eyes from 6 patients were included in this study. IOP was reduced from 23.9 [+ or -] 5.3 mmHg (mean [+ or -] standard deviation) preoperatively to 14.0 [+ or -] 5.3 mmHg at POM12 (p < 0.05). Number of glaucoma medications was reduced from 4.3 [+ or -] 1.3 pre-operatively to 1.6 [+ or -] 1.6 at POM12 (p < 0.05). Hypotony and choroidal effusion were noted in one case which resolved before POM1. Bleb needling was required in 3 of the 7 eyes (43%), with one eye requiring needling twice. By POM12, 2 of 7 eyes (29%) achieved absolute success, 4 eyes (57%) qualified success, and 1 eye (14%) was qualified as failure. Conclusion: Ab interno XEN gel stent can effectively reduce IOP and number of glaucoma medications after failed tube shunt surgery. Nonetheless, further interventions such as bleb needling may still be required to optimize IOP control. Keywords: glaucoma, MIGS, tube shunt, Ahmed glaucoma valve, Baerveldt glaucoma device, ab interno XEN implant