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Completed

NCT Number: NCT04454138

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

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.

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Key information

Conditions

Glaucoma Eye Diseases Ocular Hypertension

Age range

30 year–90 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Prism Eye Institute

Oakville, Ontario, L6H 0J8, Canada

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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).

Treatment and study plan

XEN-45 gelatin microstent

Device

Placement either in the subconjunctival space or supratenon's area

Primary outcomes

  1. Postoperative Intraocular Pressure Changes Between Targeted Supratenon's Placement of XEN-45 Gelatin Stent and Nontargeted Placement.

    Time frame: Post op year 1

    Mean change in IOP from baseline, IOP thresholds of ≥6 and ≤14 (mmHg) on no medications

  2. Postoperative Intraocular Pressure Changes Between Targeted Supratenon's Placement of XEN-45 Gelatin Stent and Nontargeted Placement 2.

    Time frame: Post op Year 1

    Mean change in IOP from baseline, IOP thresholds of ≥6 and ≤14 (mmHg) +/- Medications

  3. Postoperative Intraocular Pressure Changes Between Targeted Supratenon's Placement of XEN-45 Gelatin Stent and Nontargeted Placement 3.

    Time frame: Post op year 1

    Mean change in IOP from baseline, IOP thresholds of ≥6 and ≤17 (mmHg) on no medications

  4. Postoperative Intraocular Pressure Changes Between Targeted Supratenon's Placement of XEN-45 Gelatin Stent and Nontargeted Placement 4.

    Time frame: Post op Year 1

    Mean change in IOP from baseline, IOP thresholds of ≥6 and ≤17 (mmHg) +/- medication

  5. Postoperative Intraocular Pressure Changes Between Targeted Supratenon's Placement of XEN-45 Gelatin Stent and Nontargeted Placement 5.

    Time frame: Post op Year 1

    Mean change in IOP from baseline, IOP thresholds of ≥6 and ≤21 (mmHg) on no medications

  6. Postoperative Intraocular Pressure Changes Between Targeted Supratenon's Placement of XEN-45 Gelatin Stent and Nontargeted Placement 6.

    Time frame: Post op year 1

    Mean change in IOP from baseline, IOP thresholds of ≥6 and ≤14 (mmHg) +/- medications

Secondary outcomes

  1. Number of Participants With Postoperative Complications Between Targeted Supratenon's Placement of XEN-45 Gelatin Stent and Non-targeted Placement.

    Time frame: Post op year 1

    Presence or absence of the following complications:

    i. Starting after POM1: shallow AC w/ iridocorneal touch, any hyphema, corneal edema, wound leak/dehiscience, choroidal effusion, malignant glaucoma, dellen/non-healing epithelial defect, ptosis, diplopia.

    ii. At any point: additional glaucoma surgery, loss of light perception vision, vitreous hemorrhage, ≥2mm hyphema, hypotony maculopathy, implant migration/blockage/exposure/extrusion, macular edema, choroidal effusion/hemorrhage requiring drainage, suprachoroidal hemorrhage, retinal detachment, suture abscess/blebitis/endophthalmitis

  2. Number of Participants With Postoperative Interventions Between Targeted Supratenon's Placement of XEN-45 Gelatin Stent and Non-targeted Placement.

    Time frame: Post op year 1

    Presence or absence of the following management interventions (not considered complications): bleb needling, AC reformation, suture release, digital ocular compression, use of glaucoma medications, or laser/tpa to blocked ostomy or lumen.

Sponsors and collaborators

Lead sponsor

Prism Eye Institute

Other

Collaborators

  • Allergan

Registry information

Important dates

Study start
2019
Primary completion
2020
Study completion
2020
First posted
Jul 1, 2020
Registry last updated
Aug 14, 2020

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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