State of the art, advantages and drawbacks of XEN 63 gel stent in glaucoma surgery

Abstract

Purpose

The XEN gel stent (Allergan) is a minimally-invasive, subconjunctival bleb-forming device designed for glaucoma surgery. Originally available in three sizes (45, 63 and 140 μm), it consists of a flexible, permanent collagen implant that is positioned ab-interno.

Design

Narrative review.

Methods

A search was conducted in the Cochrane Central, PubMed/Medline, Google Scholar, Web of Science, and ClinicalTrials.gov databases for studies related to the XEN 63 model up to May 2024.

Results

Initial studies with the previous version of the XEN 63 device indicated a significant reduction in intraocular pressure (IOP), although the failure rate was over 30 % due to the absence of intraoperative mitomycin C. The complete success rate—defined as final IOP ≤18 mmHg with at least a 20 % reduction from baseline—was approximately 25 %. Subsequent reports following the introduction of the revised XEN 63 stent model demonstrated IOP reductions of 40–45 % from baseline. This newer model also significantly reduced the need for postoperative topical medications. After 12–18 months of follow-up, the complete success rates reported were around 60 %, and the final IOP values were lower than those observed with the XEN 45 stent in comparative studies. The most common postoperative complication is hypotony, which varies from 18 to 66 %. While usually subclinical and treatable with medical intervention, 3–5 % of cases lead to complications such as choroidal detachment or anterior chamber shallowing. Other infrequent adverse events include anterior chamber hemorrhage and hyphema. The rates of needing subsequent needling procedures are similar to those observed with the XEN 45 stent, ranging from 10 to 35 %.

Conclusion

The XEN 63 stent has shown promising results and greater efficacy in lowering IOP compared to the XEN 45 stent. Further research is essential to determine its long-term efficacy and confirm the rate of postoperative complications.