Automated Gonioscopy Assessment of XEN45 Gel Stent Angle Location After Isolated XEN or Combined Phaco-XEN Procedures: Clinical Implications

Precis: Angle location of the XEN implant both in isolated and in combined procedures did not appear to influence long-term outcomes. However, more posterior stent placements seem to be associated with increased early postoperative complications. Purpose: The purpose of this study was to assess success and safety outcomes of different levels of insertion of the XEN45 gel stent in the angle in standalone and combined procedures. Methods: This was a cross-sectional study of patients in whom XEN had been implanted without intraoperative gonioscopy. Automated gonioscopy was used for postoperative analysis of the XEN location, classified as anterior or posterior relative to the scleral spur. Absolute success was defined as >= 20% intraocular pressure decrease from baseline and ranging from 6 to 21 mm Hg without medication and qualified success if medicated. The need for additional drainage surgery was considered failure, but needling was allowed. Clinical data were retrieved from patient files. Results: Gonioscopy-assisted XEN location was performed on 42 eyes of 33 patients (14 isolated and 28 combined procedures) on average 18 +/- 9 months after surgery. Absolute (32% vs. 35%;P>0.99) and qualified (44% vs. 65%;P=0.22) success was similar in both anterior and posterior placements, respectively. Kaplan-Meier survival analysis yielded similar median survival times for both groups. The distribution of XEN insertion level in the angle was similar in standalone and combined procedures (P=0.75). Although overall safety outcome measures did not differ significantly, the proportion of intraoperative and early postoperative complications was higher in posterior XEN placements (P=0.03). Conclusions: Different locations of XEN45 did not seem to significantly impact late success and safety outcomes, although stents inserted more posteriorly may be associated with a higher rate of early complications. Combined implantation of XEN with phacoemulsification does not seem to influence stent location in the iridocorneal angle in a setting without intraoperative gonioscopy.