Stand-Alone Xen Gel Microstent Implantation Compared With Kahook Dual Blade Goniotomy

Both Xen gel Microstent implantation and Kahook Dual Blade (KDB) goniotomy are safe and effective as stand-alone procedures, but the Xen Gel Microstent was associated with more postoperative interventions and achieved higher success at a lower intraocular pressure threshold.

To evaluate outcomes of stand-alone Xen Gel Microstent implantation compared with stand-alone KDB goniotomy for moderate to severe glaucoma.

A retrospective, single-center, case-series analysis comparing outcomes of Xen Gel Microstent implantation and KDB goniotomy stand-alone cases in 75 eyes. Primary outcomes included intraocular pressure (IOP) reduction, glaucoma medication reduction, surgical success, and complications. Surgical success was defined using IOP<21 mm Hg and IOP<18 mm Hg thresholds, with or without glaucoma medications, and without further glaucoma surgery. Subjects were followed for at least 24 months after surgery.

Mean baseline IOP was comparable between the Xen Gel Microstent and KDB goniotomy groups (23.7±8.4 and 25.9±7.9 mm Hg, respectively, P =0.32). At 24 months after surgery, the mean IOP after Xen Gel Microstent was 14.7±3.2 mm Hg (32.7% reduction from baseline, P =0.018) and KDB goniotomy was 16.7±3.2 mm Hg (40.4% reduction from baseline, P =0.049). Although the mean IOP was significantly lower during the first month after Xen Gel Microstent implantation, no difference in mean IOP was observed between the 2 treatment groups at 24 months after surgery ( P =0.416). At 24 months after surgery, the percent reduction of IOP from baseline was not significantly different between the 2 groups. The mean reduction of glaucoma medications from baseline at 24 months was 1.69 drops after Xen Gel Microstent implantation ( P =.008) and 1.67 drops after KDB goniotomy ( P =0.038). Postoperative complications were nonvision-threatening and were not significantly different between the 2 groups ( P =0.550). Interventions not included with complications were needling performed in 21 (37%) of eyes in the Xen Gel Microstent group and Nd:YAG goniopuncture in 1 (5.6%) eye after KDB goniotomy. With an IOP threshold <21 mm Hg, surgical success was not significantly different between the 2 groups ( P =0.06). At a lower IOP threshold (<18 mm Hg), surgical success was higher after Xen Gel Microstent implantation compared with KDB goniotomy ( P =0.001).

Both stand-alone Xen Gel Microstent implantation and KDB goniotomy can effectively and safely reduce IOP for moderate to severe glaucoma. The Xen Gel Microstent was associated with a higher need for postoperative interventions and achieved greater success at a lower IOP threshold.