Implantation of the XEN® 45 Gel Stent in patients with glaucoma at a University Hospital - a retrospective quality control study.

Abstract

The XEN45 gelatine stent (Allergan, Dublin, Ireland) is a surgical option for relevant glaucoma patients (Green et al. 2018). With this retrospective chart review, we wanted to evaluate the efficiency and safety of XEN stent implantation at our university hospital clinic over a 2-year period. We included all patients who had undergone XEN stent implantation from January 2017 to December 2018 at Odense University Hospital, Denmark. Intraocular pressure (IOP) and number of pressure-lowering eye drops were registered before treatment and postoperatively at 1, 3, 6 and 12 months. All complications, reoperations and revisions were registered at the time of surgery and postoperatively. We included 27 eyes in 27 patients with a mean age of 72 years. The vast majority had open-angle glaucoma. Mean deviation (MD) was - 16 dB in average. In 9 eyes (33 %), XEN stent implantation was combined with phacoemulsification. Five eyes had previously been treated with selective laser trabeculoplasty (SLT). Otherwise, no patients had undergone previous eye surgery. All XEN stent implantations were performed by two experienced glaucoma surgeons. Seventy-eight per cent of eyes attended the 12-month visit. We found a statistically significant reduction in IOP and number of pressure-lowering eye drops at all postoperative time intervals compared with baseline (p < 0.01). Mean IOP at baseline was 17.8 ± 7.4 mmHg (range: 11–48) and 11.5 ± 3.3 mmHg (range: 6–18) at 12 months of follow-up. Thus, in this study, XEN45 Gel Stent implantation led to an average reduction of 6.3 mmHg in IOP one year after surgery. Mean number of pressure-lowering eye drops at baseline was 3.2 ± 0.9, and 1.0 ± 1.3 after 12 months of follow-up, that is an average reduction of more than 2 pressure-lowering eye drops after one year. Sixty-seven per cent of eyes did not need pressure-lowering eye drops one year after surgery. We did not find any statistically significant differences regarding IOP in eyes in which XEN stent implantation was combined with phacoemulsification, except after 1 month (p < 0.01), where IOP was higher in the combined group. The number of eyes included was too small to make any reliable conclusions regarding SLT, but there was a trend (p = 0.05) towards a difference in number of pressure-lowering eye drops after 12 months in favour of those who had not received SLT treatment. Seventy per cent of all eyes did not require any postoperative surgical interventions. Needling (22%) and choroidal effusion (15%) were the most common postoperative surgical procedure and postoperative complication, respectively. Also, one very severe complication, necrotizing scleritis, was noted in this cohort, but after months of antibiotics, steroids and surgery, the eye was saved, and visual acuity and MD had not deteriorated. Seven of our 27 patients had XEN implantation in both of their eyes. When including these eyes in the statistical analyses, the results were largely the same. We therefore conclude that XEN stent implantation is an efficient method to lower IOP and reduce the need for pressure-lowering eye drops in patients with glaucoma for at least 12 months. Most complications in this retrospective study were minor; however, one severe complication was reported. Patients should be informed that reoperation or revision is not unusual. Major limitations to this study were the relatively low number of patients included and short follow-up time. The authors wish to thank the Region of Southern Denmark.