Ab Interno Gelatin Stent With Mitomycin C Using Targeted Supra-tenon's Placement

Prism Eye Institute

Status: Completed

Conditions: Glaucoma

Treatments: Device: XEN-45 gelatin microstent

Study type: Observational

Funder types: Other; Industry

Identifiers

NCT04454138

955

Details and patient eligibility

About

The Xen-45 gelatin microstent is a novel, bleb-forming microinvasive glaucoma surgery (MIGS). Despite demonstrating similar efficacy and safety to trabeculectomy (traditional surgery), the Xen-45 gelatin microstent continues to suffer from occasional surgical failure due to fibrosis of the filtering bleb, and obstruction of the stent. During surgery, placement in a surgery known as supra-tenon's space is believed to maximize aqueous outflow, while preventing obstruction, limiting fibrosis of the bleb, and promoting long-term patency. Despite the theoretical merits, long-term data of outcomes after targeted supra-tenon's placement is needed to fully assess its potential in improving Xen-45 microstent outcomes.

Full description

The Xen-45 gelatin microstent (Allergan, Dublin, Ireland) is a novel, bleb-forming microinvasive glaucoma surgery (MIGS). Creation of a filtering bleb through the gel stent and under the conjunctiva lowers intraocular pressure (IOP) by bypassing the natural outflow pathway of aqueous. A recent retrospective cohort study showed comparable safety and risk of failure to trabeculectomy. Amongst the main advantages of this device is the ability to create a bleb without dissecting and disrupting tissue, thus decreasing the amount of wound healing and potentially limiting bleb failure. However, despite demonstrating similar efficacy and safety to trabeculectomy,2 the Xen-45 gelatin microstent continues to suffer from occasional surgical failure due to fibrosis of the filtering bleb, and obstruction of the stent. Although antimetabolites, such as mitomycin C, have decreased reactionary wound healing that can result following surgery, fibrosis may still occur, especially when the components of the Xen-45 gelatin microstent are in close proximity to the fibroblastic structures of tenon's fascia.Tenon's capsule resembles a sponge-like layer with multiple adhesions to the overlying conjunctiva and underlying episclera. Implantation of the XEN within this space creates a higher risk of obstruction and subsequent failure. To ensure the lowest potential for occlusion, bleb scarring, and failure, one must ensure careful placement of the device in the subconjunctival space, avoiding intra-tenon's placement. Placement in the supra-tenon's space is believed to maximize aqueous outflow, while preventing obstruction, limiting fibrosis of the bleb, and promoting long-term patency. Despite the theoretical merits, long-term data of outcomes after targeted supra-tenon's placement is needed to fully assess its potential in improving Xen-45 microstent outcomes.

Enrollment: 142 patients

Sex: All

Ages: 30 to 90 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Patients aged 30-90 with primary or pigmentary/pseudoexfolliative open angle, primary closed angle, or combined mechanism glaucoma with IOP of 18-40 mmHg on maximum tolerated medical therapy who received a gelatin stent with MMC at Prism Eye Institute from June 2012 to August 2019.

Exclusion criteria

• Other forms of glaucoma
• Prior incisional glaucoma surgery
• CPC
• Prior corneal graft (PKP, DALK, DSAEK, DMEK).

Trial design

142 participants in 2 patient groups

Targeted supratenon's placement of XEN 45

Description:

Placement of Xen-45 gelatin microstent in the supra-tenon's space to maximize aqueous outflow, while preventing obstruction, limiting fibrosis of the bleb, and promoting long-term patency.

Treatment:

Device: XEN-45 gelatin microstent

Non-targeted placement of XEN 45

Description:

Implantation of the XEN-45 gelatin microstent within the subconjunctival space, avoiding intra-tenon's placement.

Treatment:

Device: XEN-45 gelatin microstent