Outcomes of Ab interno Gelatin Microstent with MMC using Targeted Supra-tenon’s Placement 
Ramzi Jumaa, 1,2 Jeb Alden Ong,1,2  Pearson Wu,1,2 Iqbal Ike K. Ahmed1,2
1University of Toronto, Department of Ophthalmology and Vision Science, Toronto, Canada; 2Prism Eye Institute, Mississauga, Canada
Abstract:
Purpose: To compare the success rate and outcomes of targeted vs non-targeted supra-tenon’s placement of ab interno gelatin microstent.  Despite theoretical merits of targeting the subconjunctival space to avoid intra-tenon’s placement of microstent, there is currently no published long-term data.
Study Design: Retrospective Single-Center Case Study
Methods: Primary outcome was time to failure (IOP outside of 6-17 on no medications) on two consecutive visits despite in-clinic maneuvers (including needling).  Secondary outcomes included IOP cutoffs of 14 and 21, interventions, complications, and reoperations.
Results: In total, 65 eyes received non-targeted microstent placement, whereas, 77 eyes received targeted supra-tenon’s microstent placement. HR for non-targeted relative to targeted placement was 0.96 (95% CI 0.50 - 1.87); proportional success at 1 year were 0.49 (0.08) for non-targeted and 0.52 (0.10) for targeted microstent placement. There were 20 and 25 interventions (30.8% and 32.5% had needling with MMC for non-targeted and targeted placement), with a similar reoperation rate in both groups (12.1% and 10.7%, respectively). Non-targeted group had a slightly smaller general complication percentage (e.g. hyphema, choroidal effusion, hypotony maculopathy) of 32.3% vs. 33.8% than targeted group. As well, the targeted group also had a higher percentage of had a microstent specific complication (e.g. blocked Xen, Iris Xen Touch) compared to the non-targeted group ( 10.4% vs. 4.6%).
Conclusions: Firstly, targeted supra-tenon’s placement of the ab-interno Xen-45 gelatin microstent showed similar outcomes as the non-targeted placement. Secondly, Multivariable analysis identified no baseline characteristics that led to greater risk of failure between targeted and non-targeted microstent placement, including preop IOP >21mmHg, MD ≥-6dB, glaucoma type, age ≥75years old. Finally, these are encouraging results as they suggest the ease of using the ab-interno Xen-45 gelatin microstent.

Outcomes of ab interno gelatin microstent with MMC using targeted supra-tenon’s placement

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