Migration of XEN45 Implant: Findings, Mechanism, and Management

AIM: The aim of this study is to report the mechanism of XEN migration and its management. BACKGROUND: Over the past decade, new less invasive surgical approaches for glaucoma have been devised and carried out successfully. One such technique is the use of the XEN gel stent. We present a rare and relatively unknown complication of XEN migration and present in detail the likely mechanism by which this occurs, and its subsequent management. CASE DESCRIPTION: A 73-year-old male with primary angle closure on maximal medical treatment presented with an intraocular pressure of 30 mm Hg in the left eye. The visual acuity was 6/5, iridocorneal angles were open in all four quadrants, and the cup disc ratio was 0.4. As phacoemulsification alone was unlikely to adequately lower intraocular pressures, the patient underwent combined phacoemulsification and XEN implantation. Although the patient had a good postoperative result with pressures lowered to 11 mm Hg, 4 months after the operation, the XEN was found to have migrated 4 mm into the anterior chamber, associated with a low-grade uveitis. The patient subsequently had the XEN explanted a new XEN inserted. Pressures lowered 1 month postoperatively to 14 mm Hg. CONCLUSION: XEN migration is likely due to a combination of mechanical and frictional forces. If the XEN is positioned such that more than 2 mm is in the subconjunctival space, the XEN is likely to be angled upward and, therefore, be more susceptible to these forces and undergo migration. CLINICAL SIGNIFICANCE: It is essential that XEN implants are correctly sited and that this is confirmed intraoperatively to prevent the need for further procedures. HOW TO CITE THIS ARTICLE: Ali ZC, Khoo DI, et al. Migration of XEN45 Implant: Findings, Mechanism, and Management. J Curr Glaucoma Pract 2019;13(2):79–81.