Xen ab interno, externo outcomes comparable
PHILADELPHIA – Ab interno and ab externo Xen gel stent implantation outcomes were similar with regard to IOP and medication reductions, with the external approach demonstrating less need for postoperative bleb needling, according to a study presented at the Wills Eye Conference.
The ab interno approach, which traverses the anterior chamber to deliver the Xen stent (Allergan) is the traditional method of deployment, whereas an ab externo approach “starts from the outside in,” Robert Purgert, MD, PhD, said.
An insertion tunnel is developed beneath the conjunctiva, pierces through the sclera and enters the anterior chamber, where the stent is deposited.
“The outcomes of the ab interno approach are well described, but the outcomes of the ab externo approach remain uncharacterized, so our goal was to compare the outcomes of these two delivery methods,” Purgert said.
In a retrospective review of a single surgeon’s Xen implantation patients since 2017, 72 eyes of 61 patients were identified. Of those eyes, 42 underwent ab interno implantation and 30 underwent ab externo implantation.
At 12 months, both implantation methods resulted in statistically significant lowering of IOP and medications from baseline.
Both approaches carried similar low failure rates, with reoperation needed in 14% of ab interno eyes vs. 10% of ab externo eyes.
In the ab externo group, only 5% of eyes required needling of the bleb.
“You get to the same place as far as outcomes,” Purgert said. “But you need more needling to get there with your traditional interno approach.” – by Kate Burba
Reference: Purgert R. Outcomes of ab externo vs. ab interno Xen gel stent implantation. Presented at: Wills Eye Conference; March 5-7, 2020; Philadelphia.
Disclosure: Purgert reports no relevant financial disclosures.