Postoperative Complications of Ab Interno Gelatin Microstent

Abstract

Purpose: To report 4 previously undescribed postoperative complications in 4 cases of ab interno XEN45 Gel Stent (XEN) implantation following uncomplicated surgeries. Patients and Methods: A total of 51 consecutive XEN implantations performed between July 1, 2017 and April 30, 2018 were reviewed. All cases were performed by 7 experienced glaucoma surgeons affiliated with the William Beaumont Hospital, Department of Ophthalmology. Cases with postoperative complications were identified, and a literature review was performed on PubMed.gov between April 5, 2018 and June 2, 2018 to identify previously unreported XEN complications. Results: Case 1 consisted of an 86-year-old woman who suffered a suprachoroidal hemorrhage and associated rhegmatogenous retinal detachment following XEN implantation. One month after sclerotomy drainage and pars plana vitrectomy repair, an amputated XEN was found to have eroded through the conjunctiva. Case 2 consisted of a 68-year-old man with persistent elevated intraocular pressure due to recurrent Tenon’s capsule fibrosis who developed complete XEN retraction into the subconjunctival space. Cases 3 and 4 consisted of a 68-year-old man and a 78-year-old woman who developed occlusion of the microstent’s internal ostium by a partially detached Descemet’s membrane. Case 3 maintained normal intraocular pressure on timolol, whereas case 4 resulted in bleb failure, despite Nd:YAG laser lysis of the occluded XEN internal ostium. Conclusions: Although the XEN is a promising new surgical option for the management of primary open-angle glaucoma, it can present unique postoperative challenges that are still being elucidated. Timely intervention or prevention of these complications can be improved by early surgeon recognition and effective communication with comanaging ophthalmologists.

Comparing the efficacy of trabeculectomy and XEN gel microstent implantation for the treatment of primary open-angle glaucoma: a retrospective monocentric comparative cohort study

“…Rooney et al reported several cases of postoperative complications after XEN implantation. Gabbay et al also stated that patients should be advised regarding failure rates, possible need for bleb revision and the resumption of medication use after XEN implantation 16,48 .…”

Xen gel stent occlusion with iris pigment epithelium

“…IOP elevation after Xen gel implantation could be due to the obstruction of the stent with iris tissue, blood, detached Descemet's membrane, lens cortical material if Xen implantation is combined with cataract surgery, steroid response and subconjunctival episcleral fibrosis . The Xen occlusion commonly occurs during the early postoperative weeks and Nd:Yag laser may be employed to reopen the stent.…”

Navigating Challenges after Xen

“…It is well known and expected to have numerical hypotony after XEN implantation in the early postoperative days. There have been cases of numerical hypotony following XEN reported in the literature [43,44]. In most cases, this hypotony is transient and self-resolving, but occasionally it becomes clinical hypotony.…”

“…However, a viscoelastic with a high molecular weight (cohesive) is not recommended as it has been shown to create IOP spikes [43]. In cases of over-filtration with prominent blebs present, reports have also been published of successful management with a modified transconjunctival bleb compression suture technique and a bleb revision [44].…”