Efficacy and safety at 6 months of the XEN implant for the management of open angle glaucoma

Abstract

The purpose of this study is to evaluate the efficacy and complications of the XEN implant as a solo procedure or in association with cataract surgery in patients with open angle glaucoma (OAG). All patients who received a XEN implant between June 2017 and June 2018 were included in the study. The primary and secondary outcomes were: the reduction of the intraocular pressure (IOP) at 6 months postoperatively, the decrease of the glaucoma medications 6 months after surgery, the clinical success rate (eyes (%) achieving ≥20% IOP reduction on the same or fewer medications without secondary surgical intervention), the frequency and type of postoperative interventions as well as the complication rate. We included one hundred and seven eyes from 97 patients with primary OAG (79%), or secondary OAG (21%). Seventy-seven patients (72%) received a standalone XEN implantation and 30 (28%) underwent XEN implantation combined with phacoemusification. The IOP decreased from 20.4 mm Hg ± 6.4 preoperatively to 15.4 mm Hg ± 5.3 six months after the surgery, which represented a reduction of 24.5% (P = 1.4.10 −7). It was associated with a lowering of glaucoma medications from 2.8 ± 1.0 preoperatively to 0.6 ± 1.0 six months postoperatively (P = 3.6.10 −34). The clinical success rate was 67.2% six months after the surgery. The most frequent complications were: IOP spikes >30 mmHg (16.8%), improper position or angled drain (14.0%) and transient minimal hyphema (<1 week) (11.2%). During the follow-up, the needling was required in 34.6% of cases and a total of 10 eyes (9.4%) required a new glaucoma surgery. To conclude XEN implantation appears to be an effective short-and midterm surgical technique to control IOP in OAG with a low risk of complication. However postoperative maneuvers were frequently required to maintain efficiency. Glaucoma is the first cause of irreversible blindness 1. It is a optic neuropathy that affects more than 70 million people worldwide 2. Nowadays, reducing the intraocular pressure (IOP) is the only effective therapeutic strategy to stop the progression of glaucoma 3-5 , it includes pressure-lowering eye-drops, laser treatments and surgery. In the case of open angle glaucoma (OAG), the most performed glaucoma surgeries are trabeculectomy and non-penetrating deep sclerectomy (NPDS). These two techniques are based on a derivation of the aqueous humor towards the subconjunctival space by creating a filtration bleb (FB). As effective these filtering surgeries are, they are also accompanied by a non-negligible rate of complications such as postoperative bleb leakage, hypotony, and cataract 6-8. Fibrosis of the bleb is responsible for the majority of surgical failures 7. Rarely, an infection of the filtering bleb occurs, exposing the eye to a risk of endophthalmitis 7,8. Consequently, innovative glaucoma surgery techniques and devices described as "Minimally Invasive Glaucoma Surgeries" (MIGS) have been developed. XEN is one of these new minimally invasive therapeutic option (used for the IOP reduction procedure) c...

Effective treatment of a normal-tension glaucoma patient with bilateral ab externo XEN Gel Stent implantation

“…A number of studies have examined ab interno XEN Gel Stent implantation in mixed POAG populations and found mean IOP reductions ranging from 28 to 42.1% with postoperative IOPs ranging from 12 to 15 mmHg. 18 , 21 , 22 , 23 , 24 , 37 , 38 , 39 , 40 , 41 Direct comparison of ab interno XEN Gel Stent implantation with trabeculectomy in POAG patients found no difference in the rates of surgical success or reduction in IOP lowering medications. 24 , 39 , 42 , 43 While one study found that trabeculectomy resulted in lower postoperative IOPs, 39 others found no difference.…”

“…While the XEN Gel Stent has the theoretical potential to achieve IOPs ≤10 mmHg, in practice, post-implantation IOPs are typically in the 12–15 mmHg range in OAG patients using an ab interno approach. 18 , 21 , 22 , 23 , 24 It has been suggested that this discrepancy is due to additional outflow resistance of a suboptimal conjunctival bleb created following ab interno implantation. 25 , 26 In contrast, an ab externo approach offers the opportunity to dissect Tenon's from the episclera and optimize stent positioning, 27 which may allow for better bleb morphologies that can achieve lower IOPs closer to the theoretic limit.…”

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

“…Reported needling rates after XEN microstent implantation differ between study populations. Reported needling rates lie between 22 and 51% during the first year after surgery, and are even reported to be as high as 55% after 3 years of follow-up after XEN microstent implantation 14,18,27,28,[34][35][36][37][38][39] . Length of follow-up, aggressiveness of postsurgical treatment, patient´s preferences and targeted IOP are among the numerous factors influencing needling rates.…”

“…13 . The IOP-lowering and medication-sparing efficacy of the XEN microstent has already been demonstrated in different single and multicenter trials 12,[14][15][16] . The aim of this study was to compare the efficacy and safety profile of the XEN microstent with standard TET in a comparable group of POAG cases in a retrospective, monocentric single surgeon setting.…”

Choroidal Detachment after XEN Gel Stent Implantation

“…Among the complication of glaucoma filtration surgeries, choroidal detachment (CD) is frequently observed. The estimated incidence varies from 3% to 34% and changes accordingly to the surgical technique to the ocular and the demographic characteristics of the patients and the diagnostic technique accuracy [ 1 – 6 ]. A limited CD can be asymptomatic, resolve spontaneously, and remain undetected if not adequately investigated.…”