XEN Glaucoma Implant for the Management of Operated Uncontrolled Glaucoma: Results and Complications during a Long-Term Follow-Up

Systematic Literature Reviews Comparing the Long-Term Safety Outcomes for the Port Delivery System with Ranibizumab (PDS) Versus Other Ocular Implants

OBJECTIVES

To determine whether the types and rates of post-surgical complications associated with the Port Delivery System with ranibizumab (PDS) are comparable with those reported for other ocular implants that cross the sclera.

METHODS

Systematic literature reviews were conducted to determine the long-term (≥ 18-month) safety of ocular implants that cross the sclera in clinical trials and real-world studies. Complication types and rates were compared with those reported for the PDS in phase III clinical trials (Archway, Pagoda, and Pavilion).

RESULTS

Sixteen clinical trials (24 publications) and 43 real-world studies were identified reporting 30 complications in eyes with 15 implant types and 8 ocular diseases. Implants were associated with an acceptable, well-characterized safety profile, with most complications resolving spontaneously or with treatment. Device-related complications were reported in 0.7% (0.0-5.0%) of study eyes in clinical trials and 1.3% (0.0-14.5%) of eyes in real-world studies. Rates of conjunctival complications were 2.1% (0.0-22.8%) and 2.2% (0.9-4.6%), respectively. The overall types and rates of adverse events of special interest reported for the PDS in phase III trials (cataract, conjunctival bleb, vitreous hemorrhage, conjunctival erosion, conjunctival retraction, endophthalmitis, implant dislocation, retinal detachment, and hyphema) were within the ranges reported for other ocular implants.

CONCLUSIONS

The rates of complications reported in phase III clinical trials for the PDS were within the ranges reported for other ocular implants that cross the sclera. This suggests that the long-term safety of the PDS is consistent with other ocular devices established in ophthalmology clinical practice.

TRIAL REGISTRATION

PROSPERO international prospective register of systematic reviews: CRD5202234129, CRD42022343129.

Recanalization of Xen45 gel stent implant occlusion using 10 - 0 nylon suture in refractory glaucoma: a case report

BACKGROUND

Xen Gel Stent implant is a new minimally invasive surgical treatment for glaucoma that has been proven effectiveness and safety profile. However, it may also lead to some complications. Xen Gel Stent occlusion is a relatively rare complication reported less frequently and has limited treatment experience. In our case report, we proposed a novel surgical treatment using a 10 - 0 nylon suture to successfully recanalize the occluded Xen45 Gel Stent.

CASE PRESENTATION

A 16-year-old female patient had bilateral juvenile glaucoma for the past 5 years. Her right eye had undergone three glaucoma surgeries but failed. At a presentation to our hospital, the right eye's intraocular pressure (IOP) was 30 mmHg despite applying four different active principles. Xen45 Gel Stent implant was chosen for treatment, but six days after implantation, the IOP rose to 40 mmHg as a result of an anterior chamber tip occlusion of the Xen45 Gel Stent. Nd: YAG laser shockwave therapy was attempted but failed. The patient eventually had to return to the operating room for a revision procedure. The Xen45 Gel Stent was recanalized from the ab externo by making an L-shaped conjunctival incision at the fornix base and threading a 10 - 0 nylon suture through it. The IOP was successfully controlled in the 11-month follow-up without medication.

CONCLUSION

If postoperative occlusion arises after Xen45 Gel Stent implantation, surgery using 10 - 0 nylon suture to recanalize Xen45 Gel Stent should be considered as a relatively safe, effective that does not require removal of Xen45 Gel Stent.

Efficacy and safety of the XEN45 implant in glaucoma surgery: Retrospective study of our first 73 cases

OBJECTIVE

To analyze the results of the Xen45 implant in our hospital center, both in terms of efficacy and safety.

METHODS

Observational, retrospective, single-center study of patients undergoing Xen45 surgery at the University Hospital of Jaén between January 1, 2018 and June 31, 2021.

RESULTS

A total of 73 patients were implanted with the Xen45 device (48 with in combined surgery with phacoemulsification of the crystalline lens and 25 standalone Xen45 surgery). IOP decreased from 19.9 ± 4.9 mmHg at the first visit to a mean of 17.1 ± 5.3 (P = .001) at the sixth month. Drug use required between the first visit and Xen implantation was reduced from 2.1 ± 0.9 to 0.6 (P < .000). A second surgery was necessary in 18 patients (26.6%) in the first 6 months.

CONCLUSIONS

Glaucoma surgery by Xen45 implant, alone or combined with cataract surgery, is an effective and safe procedure for IOP lowering.

Effectiveness and Safety of Xen Gel Stent in Glaucoma Surgery: A Systematic Review of the Literature

Although topical medical therapy and selective-laser-trabeculoplasty represent the treatments of choice to reduce intraocular pressure, many patients do not achieve adequate glaucoma control; therefore, they require further options and eventually surgery. Trabeculectomy is still considered the gold standard, but the surgical management of glaucoma has undergone continuous advances in recent years, XEN-gel-stent has been introduced as a safer and less traumatic means of lowering intraocular pressure (IOP) in patients with open-angle glaucoma (OAG). This study aimed to review the effectiveness and safety of clinical data on XEN-stent in OAG patients with a Synthesis-Without-Meta-analysis (SWiM) methodology. A total of 339 studies were identified following a literature search adhering to PRISMA guidelines and, after evaluation, 96 studies are discussed. XEN63 and XEN45 device data were collected both short and long term. In addition, this document has evaluated different aspects related to the XEN implant, including: its role compared to trabeculectomy; the impact of mitomycin-C dose on clinical outcomes; postoperative management of the device; and the identification of potential factors that might predict its clinical outcomes. Finally, current challenges and future perspectives of XEN stent, such as its use in fragile or high myopia patients, were discussed.

Intraocular Pressure and Medication Changes Associated with Xen Gel Stent: A Systematic Review of the Literature

The Xen gel stent (Allergan Inc, an AbbVie company; Dublin, Ireland) was conceived as an option for patients requiring modest IOP reduction but for whom trabeculectomy was not yet indicated. As with any glaucoma surgery, establishing criteria for patient selection and identifying factors that contribute to a high likelihood of success are important. To help guide clinical decision-making, a systematic review of published studies on the gel stent was performed, with the goal of understanding postoperative outcomes based on clinical and patient factors. Results were organized around a series of pertinent clinical questions based on scenarios encountered in clinical practice. Criteria for including studies were intentionally broad, with the objective of simulating the diverse population of glaucoma patients encountered in real-world practice. Outcomes for IOP and medication reduction postoperatively were assessed in various analyses, including in eyes with various glaucoma types and severity; in eyes naïve to surgery as well as those with a history of prior incisional glaucoma surgery; and when surgery was performed as a standalone procedure or at the time of cataract surgery. The results of each of the various analyses were consistent in demonstrating that successful gel stent surgery achieved a postoperative IOP of approximately 14.0 mm Hg and reduction to fewer than 1 glaucoma medication. Additional data are shown on outcomes by method of implant (ab interno vs ab externo); intraoperative use of antifibrotics; and rates of needling in published studies.

Safety and Efficacy of the Preserflo® Microshunt in Refractory Glaucoma: A One-Year Study

Purpose: To evaluate the safety and efficacy of Preserflo^® microshunt implantation in eyes with refractory glaucoma. Methods: In this retrospective study, a cohort of patients who underwent Preserflo^® microshunt implantation between April 2019 and August 2020 for refractory glaucoma were evaluated. At the time of surgery, all eyes had uncontrolled intraocular pressure (IOP) despite maximally tolerated medical therapy and at least one previous failed glaucoma filtering surgery. The primary outcome was a complete success, defined as postoperative IOP ≤ 21 mm Hg with an IOP reduction ≥ 20% and no repeat filtering surgery. The secondary outcome was qualified success, defined as a complete success with the use of antiglaucoma medications. The rates of needling, bleb repair, and postoperative complications were also recorded. Results: Forty-seven eyes with a mean preoperative IOP of 30.1 ± 7.1 mm Hg and a mean of 3.4 ± 1 glaucoma medications were included. The mean number of previous surgeries prior to microshunt implantation was 2.3 ± 1.3. After 1 year, the mean IOP was significantly reduced to 18.8 ± 4.6 mm Hg, with the mean number of medications significantly reduced to 1.4 ± 1.2. Complete success was achieved in 35% of eyes, and a qualified success in 60% of eyes. A decrease in IOP of at least 30% was found in 55% of eyes. Needling or bleb repair was performed in 49% of eyes. Complications were minimal and transient, except for one eye which presented with tube extrusion, and another eye with a transected tube. A repeat glaucoma surgery had to be performed in 17% of eyes. Conclusions: The Preserflo^® Microshunt provided moderate success but a significant reduction in IOP, with a good safety profile after one year of follow-up in eyes at high risk for failure of filtering surgery.

Comparative Cost-effectiveness of Trabeculectomy versus MicroShunt in the US Medicare System

PURPOSE

To assess the societal cost-utility of the MicroShunt compared with trabeculectomy for the surgical management of glaucoma in the US Medicare system.

DESIGN

Cost-utility analysis using efficacy and safety results of a randomized controlled trial and other pivotal clinical trials.

PARTICIPANTS

Markov model cohort of patients with open-angle glaucoma.

METHODS

Open-angle glaucoma treatment costs and effects were analyzed with a deterministic model over a 1-year horizon using TreeAge software. Health states included the Hodapp-Parrish-Anderson glaucoma stages (mild, moderate, advanced, blind) and death. Both treatment arms received additional ocular hypotensive agents to control intraocular pressure (IOP). Treatment effect was measured as mean number of ocular hypotensive medications and reduction in IOP, which had a direct impact on transition probabilities between health states. Analyses of scenarios were performed with longer time horizons. One-way sensitivity and probabilistic sensitivity analyses were conducted to assess the impact of alternative model inputs. Both treatment arms were subject to reported complication rates, which were factored in the model.

MAIN OUTCOME MEASURES

Incremental cost per quality-adjusted life-year (QALY) gained.

RESULTS

At 1 year, the MicroShunt had an expected cost of US dollars (USD) 6318 compared with USD 4260 for trabeculectomy. MicroShunt patients gained 0.85 QALYs compared with 0.86 QALYs for trabeculectomy, resulting in a dominated incremental cost-utility ratio of USD 187 680. Dominance is a health economic term used to describe a treatment option that is both more costly and less effective than the alternative. The MicroShunt remained dominant in 1-way sensitivity analyses using best-case input parameters (including a device fee of USD 0). At a willingness-to-pay threshold of USD 50 000, the likelihood of the MicroShunt being cost-effective was 6.4%. Dominance continued in longer time horizons, up to 20 years.

CONCLUSIONS

Trabeculectomy appears to be a dominant treatment strategy over the MicroShunt in the surgical management of glaucoma. More independent, long-term studies are required for the MicroShunt and other subconjunctival microstent devices to evaluate their use in clinical practice.

Impact of Primary Needling on the XEN Implant Clinical Outcomes: A Real-Life Retrospective Study

Purpose

To assess the effectiveness and safety of primary-needling in eyes who underwent a XEN45 implant.

Methods

Retrospective and single center study. Consecutive patients with early-to-moderate open-angle glaucoma (OAG) or ocular hypertension, who underwent XEN45 surgery, either alone or combined with phacoemulsification, and had at least a valid 12-month post-operative visit, were included in the study. Primary needling was performed by using a 30-gauge needle without viscoelastic. Subjects were divided in two groups: Eyes who underwent XEN+primary-needling (needling) and those who underwent XEN without primary-needling (no-needling). The primary end-point was the mean change in IOP from baseline to the last follow-up visit.

Results

Sixty-three eyes, 19 (30.2%) in the needling group and 44 (69.8%) in the no-needling one, were included in the study. There were not significant differences in mean IOP lowering between needling and no-needling groups at month-12 (mean difference −2.5±5.3 mm Hg, p=0.0926). No significant differences in mean reduction of ocular-hypotensive medications were observed between needling and no-needling groups, p=0.8690. At month-12, 50 (80.6%) had blebs considered as functioning, with no difference between groups, p = 0.5631. At month-12, 59 (93.7%) eyes were classified as success, with no significant differences between needling (17/19) and no-needling (42/44) groups, p=0.3754. Secondary needling was performed in 8 (12.7%) eyes, without differences between groups (p=0.6333).

Conclusion

Primary needling, at the time of surgery, was a safe procedure in OAG patients who underwent a XEN implant, although it was not associated with a lower postoperative IOP or less ocular hypotensive medications.

The Outcomes of XEN Gel Stent Implantation: A Systematic Review and Meta-Analysis

Purpose

XEN gel stents are used for the treatment of open-angle glaucoma (OAG), including primary and secondary glaucoma that are uncontrolled by previous medical therapy and cases with previous failed surgery. Our aim was to systematically review of the clinical data of currently published ab-interno XEN gel stents with an emphasis on intraocular pressure (IOP), antiglaucoma medication outcomes, and safety profiles.

Methods

We analyzed all of the publications (MEDLINE, EMBASE, Cochrane Library) on the ab-interno XEN gel stent to evaluate the reduction in IOP and antiglaucoma medications following the procedure. The primary outcomes measured for the meta-analysis were reduction in IOP and anti-glaucoma medications. The secondary outcome were adverse events. For each study, we used a random effects analysis model to calculate the mean difference and 95% confidence intervals for the continuous results (reduction in IOP and antiglaucoma medications) using the inverse variance statistical method.

Results

Five hundred twenty-seven articles were checked and 56 studies were found to be relevant with a total of 4,410 eyes. There was a significant reduction in IOP as well as in the number of medications required in patients treated with ab-interno XEN implant either alone or combined with cataract surgery. This new treatment for various types of glaucoma reduced the IOP by 35% to a final average close to 15 mmHg. This reduction was accompanied by a decrease in the number of antiglaucoma medications in all the studies, approximately 2 classes of medication at the price of more needlings. The overall complete success rate was 21.0–70.8% after 2 years using strict criteria originally designed to record success rate in filtration surgery. The incidence of complications vision-threatening was low at <1%.

Conclusions

XEN gel stent was effective and safe for primary and secondary OAG. Further studies should be performed to investigate the impact of ethnicity on the success and failure rate after XEN implantation.