Surgeon perspectives on learning ab-interno gelatin microstent implantation

Budget impact analysis of the XEN®63 for the treatment of primary openangle glaucoma in Spain

BACKGROUND AND OBJECTIVE

To evaluate the economic impact in Spain derived from the introduction of the XEN®63 implant as a surgical alternative in the management of primary open angle glaucoma (POAG) with or without cataract in refractory patients.

MATERIALS AND METHODS

A budget impact analysis was designed to estimate the costs of surgical treatment of POAG from the perspective of the Spanish National Health System (NHS), over a time horizon of 1 year. The comparators considered (trabeculectomy, deep non-penetrating sclerectomy, Ahmed valve, iStent inject, Preserflo® microshunt and XEN®45) correspond to those used in Spanish public clinical practice. For the calculation of the target population, market shares and resource use in terms of follow-up visits, additional procedures and post-surgery complications, data from the literature were used and validated with a panel of 4 experts. Unit costs (€ 2021) were obtained from the ESALUD database.

RESULTS

The inclusion of XEN®63 could generate savings of €2,569,737 after one year since its introduction, derived from savings in the cost of the implant and procedure (-€423,120; -0.7%), follow-up visits (-€777,407; -4.5%), additional procedures (-€1,048,145; -20.6%) and post-surgery complications (-€321,065; -14.2%).

CONCLUSIONS

The incorporation of XEN63®in the surgical arsenal for the treatment of refractory POAG with and without cataracts could generate savings for the NHS.

Efficacy of ab-interno gelatin microstent implantation in primary and refractory glaucoma

OBJECTIVE

To evaluate the outcomes of ab interno gelatin microstent implantation alone and in combination with phacoemulsification for the reduction of intraocular pressure (IOP).

DESIGN

Retrospective cohort study.

PARTICIPANTS

141 eyes of 141 patients with any glaucoma subtype, including refractory glaucoma, operated in the Centre Hospitalier de l'Université de Montréal (CHUM) from 2015-2018. Patients were included if they were over 40 years of age and had a preoperative IOP of >18 mm Hg on maximum tolerated medical therapy.

METHODS

All patients received ab-interno microstent implantation (XEN-45, Allergan, Madison, NJ) with mitomycin C +/- combined phacoemulsification. The primary outcome was complete surgical success (IOP 6-18 mm Hg and <20% reduction from baseline without IOP medications or reoperations or cyclophotocoagulation); secondary outcomes included qualified success allowing for medications, percentage reduction in mean IOP and medications, and reduction in number of complications, interventions, and reoperations.

RESULTS

Mean follow-up was 30.5 ± 10.2 months (±SD). Mean IOP was 23.3 ± 7.0 mm Hg on 3.4 ± 0.8 medications at baseline and 13.3 ± 4.7 mm Hg on 1.9 ± 1.5 medications at 24 months of follow-up (p < 0.001). From 24-month survival analysis estimates, complete success was achieved in 34.1% of microstent eyes versus 20.7% with combined phacoemulsification (p = 0.02); 79.1% versus 75.1% achieved qualified success, respectively (p = 0.86). Cases with combined phacoemulsification had a higher rate of failure (hazard ratio [HR] = 1.6, 95% CI 1.1-2.3, p = 0.02). Needling with mitomycin-C or 5-fluorouracil postoperatively occurred in 54 eyes (38.3%). Complications included transient hypotony (10.6%), transient hyphema (6.4%), macular edema (4.3%), and microstent exposure (2.8%). There were 33 eyes (23.4%) with reoperations and 14 (9.9%) requiring subsequent cyclophotocoagulation lasers.

CONCLUSIONS

Microstent implantation required topical therapy in most cases 24 months following surgery in primary and refractory glaucoma and, when combined with phacoemulsification, had a higher risk of failure.

Surgeon Experience as a Risk Factor for Short-Term Failure for Ab Interno Gelatin Microstent: A Canadian Multicenter Propensity-Matched Study

PURPOSE

To compare the efficacy and safety of early versus later ab interno gelatin microstent placement with mitomycin C.

DESIGN

Canada-wide, multicenter, retrospective propensity score-matched cohort study.

PARTICIPANTS

Two hundred seventy eyes (135 early cases and 135 later cases) with no prior incisional surgery.

METHODS

Surgeons' first 20 patients (early cases group), from 6 glaucoma surgeons across 4 Canadian sites, were matched 1:1 to patients with the closest propensity score from the later (21+) patients (later cases group).

MAIN OUTCOME MEASURES

Primary outcome was hazard ratio (HR) of failure of the early versus later cases groups, with failure defined as IOP of less than 6 mmHg with more than 2 lines of vision loss or more than 17 mmHg with no medications (complete success) on 2 consecutive visits despite in-clinic maneuvers (including needling) more than 1 month after surgery. Secondary outcomes were HRs for failure, defined as IOP outside the range of 6 to 14 mmHg and 6 to 21 mmHg with and without allowing for medications (qualified success), interventions, complications, and reoperations.

RESULTS

Hazard ratio of failure for early versus later cases groups was 1.38 (95% confidence interval [CI], 0.97-1.96) for the IOP range of 6 to 17 mmHg, 1.29 (95% CI, 0.90-1.84) for 6 to 14 mmHg, and 1.48 (95% CI, 1.03-2.13) for 6 to 21 mmHg without medication and 0.95 (95% CI, 0.55-1.64), 0.95 (95% CI, 0.61-1.48), and 0.95 (95% CI, 0.52-1.75) for the same IOP ranges allowing for medications. Needling rates were 43.0% (early cases group) and 41.5% (later cases group). Complication rates after 1 month occurred in 9.6% (early cases group) and 11.1% (later cases group; P = 0.69). Reoperation rates were 14.8% (early cases group) and 8.1% (later cases group; P = 0.08).

CONCLUSIONS

There is some evidence for improved success in the later cases group. Similar needling rates, similar complication rates, and a slightly higher reoperation rate were found for the early cases group. The results suggest that this procedure can be adopted by existing surgeons with current training regimens, although they may see an improvement in their success outcomes over time.

Technique of Xen Implant Revision Surgery and the Surgical Outcomes: A Retrospective Interventional Case Series

Purpose

The Xen® Gel Stent (Allergan, Irvine, CA, USA) is a minimally invasive glaucoma surgery device implanted to reduce intra-ocular pressure (IOP) in glaucoma. The stents can fail to drain post-operatively due to scarring of the conjunctiva around the stent opening. Data on the success rates of revision surgery in patients with Xen stent failure are scarce. We present the first detailed report of the steps, outcomes and complications of Xen revision surgery with 12 months of follow-up data.

Methods

We share our experiences on the circumstances in which to perform Xen revision surgery, the steps of the surgery and the results of a retrospective interventional case series of all Xen revisions performed at a single centre from 2013 to 2018.

Results

A total of 151 Xen implants were inserted into eyes at our tertiary centre during the study period, of which 21 eyes (patients) underwent revision surgery. Mean pre-operative IOP was 26.1 (standard deviation 8.3) mmHg with the patient on two drops of anti-glaucoma medication. Four patients were excluded from the analysis due to incomplete data (medical records were unavailable for 2 patients; 1 patient died shortly after surgery; and 1 patient moved to another area). A non-functioning Xen implant was identified in another patient during revision surgery, and the procedure was converted to a trabeculectomy. The remaining 16 patients were included in the analysis, all of whom had a minimum follow-up of 12 months, with the longest follow-up being 4 years following revision surgery. Of these 16 patients, four required needling and 5-fluorouracil injection in the first 12 months following revision surgery, three required further glaucoma drainage surgery due to the failure of the revision surgery to control IOP in the first year and one suffered bleb-related endophthalmitis at the site of previous trabeculectomy surgery. Mean IOP at 12 months following revision surgery was 16.3 (standard deviation 3.7) mmHg on 0.7 drops of anti-glaucoma medication, which equates to a 37.5% reduction in IOP and a 65% reduction in the amount of IOP-lowering drops required.

Conclusion

Our study shares experience on when to perform Xen revision surgery and the steps required. The results of our small cohort are the first in the literature and show that revisions can achieve promising IOP and medication reductions. Some patients still require needling in the post-operative period to optimise outcomes.

[XEN-45 Gel Stent implant in glaucoma treatment]

The XEN-45 drainage implant is a hypotensive device made of hydrophilic gelatin and stabilized by glutaraldehyde. The implant is designed for modern Microinvasive Glaucoma Surgery (MIGS). Being installed ab interno, the stent drains aqueous fluid from the anterior chamber into the subconjunctival space. According to indications, XEN-45 can be used in treatment of primary open angle glaucoma, pseudoexfoliation or pigment glaucoma with uncompensated intraocular pressure amid maximum tolerated hypotensive therapy, and refractory glaucoma including cases with history of unsuccessful surgery. The implant can also be effectively used in combination with phacoemulsification. The article describes the structure and implantation process of the XEN drainage and reviews existing clinical trials on its effectiveness. The article also presents results on hypotensive efficacy of the implant, as well as characteristics and complications of postoperative management.