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

I - PReCIS: Dear Editor,Angle location of the XEN implant both in isolated or combined procedures did not appear to influence long term outcomes. However, more posterior stent placements seem to be associated with increased early post-operative complications. PURPOSE 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 Cross-sectional study of patients in whom XEN had been implanted without intra-operative gonioscopy. Automated gonioscopy was used for post-operative analysis of the XEN location, classified as anterior or posterior relative to the scleral spur. Absolute success was defined as ≥20% IOP decrease from baseline and ranging from 6 to 21▒mmHg without medication and qualified success if medicated. Need for additional drainage surgery was considered failure but needling was allowed. Clinical data was retrieved from patient file. 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. Distribution of XEN insertion level in the angle was similar in standalone and combined procedures (P=0.75). While overall safety outcome measures did not differ significantly, the proportion intra-operative and early post-operative 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 ICA in a setting without intra-operative gonioscopy.