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

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

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

Conditions
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Glaucoma

Intervention / Treatment
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* Device: XEN-45 gelatin microstent


Participation Criteria
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Eligibility Criteria
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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).

Ages Eligible for Study
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Minimum Age: 30 Years
Maximum Age: 90 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Targeted supratenon's placement of XEN 45<br>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. | Device: XEN-45 gelatin microstent<br>* Placement either in the subconjunctival space or supratenon's area<br>|
| Non-targeted placement of XEN 45<br>Implantation of the XEN-45 gelatin microstent within the subconjunctival space, avoiding intra-tenon's placement. | Device: XEN-45 gelatin microstent<br>* Placement either in the subconjunctival space or supratenon's area<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postoperative Intraocular Pressure Changes Between Targeted Supratenon's Placement of XEN-45 Gelatin Stent and Nontargeted Placement. | Mean change in IOP from baseline, IOP thresholds of ≥6 and ≤14 (mmHg) on no medications | Post op year 1 | 
| Postoperative Intraocular Pressure Changes Between Targeted Supratenon's Placement of XEN-45 Gelatin Stent and Nontargeted Placement 2. | Mean change in IOP from baseline, IOP thresholds of ≥6 and ≤14 (mmHg) +/- Medications | Post op Year 1 | 
| Postoperative Intraocular Pressure Changes Between Targeted Supratenon's Placement of XEN-45 Gelatin Stent and Nontargeted Placement 3. | Mean change in IOP from baseline, IOP thresholds of ≥6 and ≤17 (mmHg) on no medications | Post op year 1 | 
| Postoperative Intraocular Pressure Changes Between Targeted Supratenon's Placement of XEN-45 Gelatin Stent and Nontargeted Placement 4. | Mean change in IOP from baseline, IOP thresholds of ≥6 and ≤17 (mmHg) +/- medication | Post op Year 1 | 
| Postoperative Intraocular Pressure Changes Between Targeted Supratenon's Placement of XEN-45 Gelatin Stent and Nontargeted Placement 5. | Mean change in IOP from baseline, IOP thresholds of ≥6 and ≤21 (mmHg) on no medications | Post op Year 1 | 
| Postoperative Intraocular Pressure Changes Between Targeted Supratenon's Placement of XEN-45 Gelatin Stent and Nontargeted Placement 6. | Mean change in IOP from baseline, IOP thresholds of ≥6 and ≤14 (mmHg) +/- medications | Post op year 1 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants With Postoperative Complications Between Targeted Supratenon's Placement of XEN-45 Gelatin Stent and Non-targeted Placement. | 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 | Post op year 1 | 
| Number of Participants With Postoperative Interventions Between Targeted Supratenon's Placement of XEN-45 Gelatin Stent and Non-targeted Placement. | 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. | Post op year 1 |