Three-year effectiveness and safety of the XEN gel stent as a solo procedure or in combination with phacoemulsification in open-angle glaucoma: a multicentre study

Mid-term surgical success after transscleral ab interno glaucoma gel stent implantation

PURPOSE

To investigate the surgical success and efficacy of XEN45 implantation (XEN45 μm, AbbVie Inc., USA) with and without combined cataract surgery up to the first 5 years.

METHODS

In a prospective observational monocentric trial, 192 eyes of 157 patients with open-angle glaucoma received either XEN45 implants only (solo surgery group) or combined surgery/cataract surgeries (combined surgery group). Surgical success (qualified and full success; IOP-limit: ≤12, 15, 18, 21 mmHg), time to secondary IOP-lowering procedure, IOP and number of IOP-lowering medications were analysed for 1, 2, 3, 4 and 5 years.

RESULTS

Compared to baseline, IOP (24.1 ± 8.1 to 12.6 ± 2.8 mmHg, -48%, p < 0.001) and the number of IOP-lowering medications (3.0 ± 1.0 to 1.5 ± 1.2, -50%, p < 0.001) decreased significantly at 5 years. Although no differences between IOP and the number of IOP-lowering medication courses between the groups were detected at 5 years (p > 0.11), the combined procedure (63%, 37%) showed better success rates compared to the solo procedure (36%, 13%) in the definition IOP ≤18 and ≤12 mmHg (p = 0.035, 0.028). Solo XEN45 procedures had a higher rate of secondary IOP-lowering procedures compared to combined XEN45 cataract procedures (hazard ratio: 2.02, 95%CI: 1.03-3.97, p = 0.04). Twenty per cent of the eyes, including both procedures, required a secondary IOP-lowering procedure within 5 years.

CONCLUSIONS

The XEN45 implant is effective in lowering IOP and the number of IOP-lowering medications in patients with open-angle glaucoma in the mid-term. Comparing XEN45 implant results with the results of trabeculectomy available in current literature, we speculate that there might be a higher surgical success rate without medications in favour of trabeculectomy.

Matched case-control comparison of surgical success after XEN45 Gel Stent and PRESERFLO MicroShunt implantation in a Caucasian population

BACKGROUND

The aim of this study was to compare the outcome of implantation of a XEN45 Gel Stent with the outcome of implantation of a Preserflo MicroShunt in a matched-pair analysis in eyes being naïve to filtering surgery.

METHODS

In this comparative, retrospective study, 50 eyes that had undergone XEN45 Gel Stent implantation were compared with 50 eyes after Preserflo implantation. Follow-up was at least 6 months, and surgical success was measured by criteria A (IOP < 21 mmHg, IOP reduction >20%, no repeat surgery); criteria B (IOP < 18 mmHg, IOP reduction >20%, no repeat surgery); and criteria C (IOP ≤15 mmHg, IOP reduction ≥40%, no repeat surgery).

RESULTS

After a follow-up period of 12 months, mean IOP had decreased from preoperative 25.2 ± 4.8 mmHg in the XEN group to 14.5 ± 4.0 (n = 35) and from 25.3 ± 6.8 mmHg to 11.9 ± 2.9 (n = 41) in the Preserflo group, respectively. The IOP at the last follow-up of the two groups differed significantly (p < 0.01). The probability of surgical success did not differ concerning Criteria A and B, but surgical success was significantly higher in the Preserflo group for Criteria C (60%, p < 0.01).

CONCLUSION

Both the Preserflo and XEN45 Gel Stent provide an effective and safe treatment option for advanced glaucoma and have a high potential to reduce intraocular pressure. Absolute IOP levels of <16 mmHg after 12 months were significantly more frequent in the Preserflo group.

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.

Long-term effectiveness and safety of XEN45 in open-angle glaucoma patients

BACKGROUND

To investigate the long-term effectiveness and safety of XEN45 implant, either alone or in combination with phacoemulsification, in eyes with open-angle glaucoma (OAG).

METHODS

Retrospective and single center study conducted on consecutive OAG patients who underwent a XEN45 implant between February-2017 and December-2021. The primary endpoint was the mean intraocular pressure (IOP) lowering from preoperative values. Surgical success was defined as an IOP-lowering from preoperative values ≥ 20% and an IOP absolute value between 6 and 13 mm Hg, without (Complete-success) or with (Qualified-success) antiglaucoma medications.

RESULTS

A total of 158 eyes (34 (21.5%) eyes XEN-solo and 124 (78.5%) XEN + Phaco) were included. The median follow-up time was 28.5 months. In the overall study population, the mean preoperative IOP was significantly lowered from 19.4 ± 6.5 mm Hg to 12.4 ± 5.0 mm Hg. The mean preoperative (95% confidence interval) IOP was significantly lowered from 21.3 (19.3-23.2) mm Hg and 18.8 (17.7-20.0) mm Hg to 12.0 (10.4-13.6) mm Hg and 12.5 (11.6-13.5) mm Hg in the XEN-Solo and XEN + Phaco groups, respectively (p < 0.0001 each, respectively). The mean number of ocular-hypotensive medications was significantly reduced in the overall study sample (from 3.4 ± 0.9 to 0.9 ± 1.3, p < 0.0001), XEN-Solo (from 3.5 ± 1.1 to 0.6 ± 1.0, p < 0.0001, and XEN + Phaco (from 3.4 ± 1.1 to 0.9 ± 1.3, p < 0.0001) groups. Eighty-four (53.2%) eyes were categorized as success, with 49 (58.3%) classified as complete success. Eighty-one (51.3%) eyes underwent needling and 15 (9.5%) eyes required an additional surgical procedure. One (0.6%) eye had endophthalmitis.

CONCLUSION

XEN implant, either alone or in combination with phacoemulsification significantly lowered IOP and reduced the need of ocular-hypotensive medication, while maintaining a good safety profile.

Long-term efficacy and safety of XEN-45 gel stent implantation in patients with normal-tension glaucoma

BACKGROUND

Minimally invasive bleb surgery using the XEN-45 gel stent has not been established for the treatment of normal-tension glaucoma (NTG). The main objective of this study was to evaluate the long-term treatment efficacy and safety of XEN-45 in eyes with uncontrolled NTG.

METHODS

A retrospective analysis of patients with NTG who underwent XEN-45 gel stent implantation at university hospital Tuebingen between 2016 and 2021. The primary outcome measure was surgical success after three years defined as lowering of intraocular pressure (IOP) of ≥ 20%, with target IOP between 6 and 15 mmHg. Success was complete without and qualified irrespective of topical antiglaucoma medication use. The need for further glaucoma surgery, except for needling, was regarded as a failure. The secondary outcome measures included changes in mean IOP, number of antiglaucoma medications, and needling and complication rates.

RESULTS

Twenty-eight eyes from 23 patients were included in the final analysis. Complete and qualified success rates were 56.5% and 75% after three years, respectively. Mean postoperative IOP ± standard deviation decreased significantly after three years from 19.3 ± 2.0 mmHg at baseline to 13.7 ± 4.2 mmHg (n = 22; p < 0.0001). The median number of antiglaucoma medications decreased from 2 (range 0-4) to 0 after three years (range 0-3; p < 0.0001). Sixteen eyes (57%) required a median of 1 (range 1-3) needling procedures. One eye required further glaucoma surgery. No sight-threatening complications were observed.

CONCLUSION

The XEN-45 stent is effective and safe for the long-term treatment of NTG. However, needling was frequently required to improve outcomes.

XEN45 gel stent in the treatment of pigmentary glaucoma: A two-year follow-up

PURPOSE

To investigate safety and efficacy of the XEN gel stent in patients with pigmentary glaucoma (PG).

METHODS

A retrospective analysis of 26 eyes of 19 patients with PG undergoing XEN gel stent implantation was performed. Best-corrected visual acuity, intraocular pressure (IOP), and number of antiglaucoma medications were analyzed preoperatively, and at 2 weeks and 3, 6, 12, and 24 months after surgery. Success, needling, and complications were analyzed. Complete success was defined as an IOP reduction of >20% and achieving a target IOP of ≤18, ≤15, or ≤12 mmHg without antiglaucoma medication. Qualified success was indicated if the IOP target was reached with or without medication.

RESULTS

Mean IOP decreased significantly from 27.6 ± 14.3 (standard deviation, SD) mmHg to 14.3 ± 4.6 mmHg after one year (p < 0.001) and 15.1 ± 2.7 mmHg (p < 0.001) after two years. The median number of hypotensive drugs declined significantly from 4 (range: 3-5) to 0 (0-2) and 0 (0-3) after one and two years, respectively. After two years, complete success with an IOP of ≤18 mmHg and ≤15 mmHg was achieved in 73.1% and 61.5%, respectively. Half of the eyes required needling after a median time of 8 months (0.5-34 months). No sight-threatening complications were observed.

CONCLUSION

The XEN gel stent is a safe and effective surgical treatment option for PG. Needling is an important part of the procedure and should be communicated preoperatively to the patients.

Using a Novel, Subconjunctival, Sustained-Release Mitomycin C Formulation in a Rabbit Model of Filtration Surgery with Gel Stent Implantation

Purpose: To investigate gel stent implantation with and without intraoperative sustained-release mitomycin C (MMC SR) in a rabbit model for gel stent implantation, and to examine aqueous humor outflow (AHO) postimplantation. Methods: Four groups of rabbits were included. Group 1 was untreated (control). Groups 2, 3, and 4 received the gel stent without MMC, with MMC solution (subconjunctival injection), and with MMC SR (subconjunctival injection), respectively. Intraocular pressure (IOP) and AHO were assessed via tonometry and indocyanine green-based angiography, respectively. The main efficacy measure was change in IOP from baseline. Results: Following gel stent implantation, Groups 2, 3, and 4 maintained ≥20% IOP reduction (response) for a median duration of 1 week, 6.5 weeks, and 30 weeks, respectively. Angiography showed normal aqueous humor drainage (Group 1) beginning at the perilimbal trabecular plexus and continuing posteriorly to episcleral outflow vessels. Following implantation, drainage occurred preferentially and directly into the subconjunctival bleb. Conclusions: Gel stent implantation with MMC SR was most effective in achieving sustained, long-term IOP reduction in the rabbit model, compared with implantation with or without MMC solution. Bleb presence and the postimplantation aqueous angiography results indicated redirection of the AHO to the subconjunctival vasculature and presumed lymphatics, suggesting efficient glaucoma filtration to lower IOP in this model. This rabbit model and aqueous angiography may help refine understanding of the mechanism of action of minimally invasive glaucoma surgeries and ultimately translate to improved surgical devices and procedures for patients with glaucoma.

Five-year outcomes of ab interno Xen 45 gel stent implantation

BACKGROUND

To assess the safety and 5-year efficacy of ab interno XEN 45 gel stent implantation with phacoemulsification in primary open-angle glaucoma (POAG).

METHODS

Single-centre, single-surgeon, retrospective case note review of consecutive OAG patients who underwent ab-interno gel stent placement combined with phacoemulsification. Surgeries were performed between 2/01/2014 and 2/01/2016.

PRIMARY OUTCOME MEASURES

mean reduction in intraocular pressure (IOP) and change in number of ocular hypotensive medications from baseline (follow-up range 1-7 years; mean 54 months).

SECONDARY OUTCOME MEASURE

change in visual field mean deviation (VFMD) from baseline. Safety data included intraoperative and post-operative complications and adverse events. Failure was defined by IOP reduction < 20% despite maximum medical therapy, the need for further laser or surgical intervention. At 5 years, 75% of eyes were free from failure (95% CI 64 to 83%).

RESULTS

Ninety-one eyes were analysed. Mean (SD) IOP and medications decreased from 20.2 (6.4) mmHg and 2.9 (1.0) at baseline to 15.4 (3.6) mmHg (p < 0.001) and 1.5 (1.4) medications at 5 (p < 0.001) years. Baseline mean VFMD (SD) was - 10.3dB (8.5) reducing to - 10.9(8.2) (p < 0.01) at 5 years. Two (2%) eyes had intraoperative complications, 4 (4.3%) experienced post-operative AEs, and 13 (14%) required secondary surgical intervention (SSI).

CONCLUSION

The gel stent combined with phacoemulsification was effective in reducing IOP and medications over 5 years, with an acceptable safety profile. Visual field change was clinically acceptable through the study period.

Combined versus standalone XEN45 Gel Stent implantation in either phakic or pseudophakic patients: a case-matched study

PURPOSE

To determine differing outcomes among either phakic or pseudophakic patients who received standalone XEN45 Gel Stent (Allergan, an AbbVie Company, CA, USA) implantation and patients who underwent combined surgery with phacoemulsification.

METHODS

This retrospective single-center study involved 180 eyes of 180 participants who underwent XEN45 Gel Stent implantation, of which 60 eyes received combined surgery with phacoemulsification (combined group). Standalone stent implantation was performed on 60 phakic (phakic group) and on 60 pseudophakic eyes (pseudophakic group). The groups were matched in a ratio of 1:1:1 based on multiple criteria. Successful surgery was defined by three scores: IOP at the longest follow-up of < 21 mmHg (Score A) or < 18 mmHg (Score B) and an IOP reduction > 20% or IOP ≤ 15 mmHg and an IOP reduction ≥ 40% (Score C). In all scores, one open conjunctival revision was allowed, and additional repeat surgery was considered a failure.

RESULTS

After an average follow-up time interval of 20.6 ± 12.6 months, there was a mean IOP-reduction by 37% among the entire cohort. Comparative analysis between the three groups did not show significant differences regarding postoperative IOP, postoperative medication score, side effects, revision rate, repeat surgery rate or success rate. A dysfunctional stent was detected in eight eyes (4%) during open conjunctival revision in 76 eyes.

CONCLUSION

The clinical endpoints investigated did not differ significantly among either phakic or pseudophakic patients who received standalone stent implantation and patients who underwent combined surgery. However mean latency between primary stent implantation and first revision surgery after combined surgery was markedly shorter.

Navigating hypotony challenges with XEN gel implantation

INTRODUCTION

The XEN Gel, a hydrophilic tube meticulously crafted to adhere to the principles of the Hagen - Poiseuille law, is designed to facilitate efficient aqueous shunting without inducing hypotony. Implantable ab interno or ab externo, with or without conjunctival opening, the device shows no significant outcome differences. Despite numerical hypotony signaling failure, patients may fare well below 6 mmHg.

AREAS COVERED

This review provides insights into device variability, challenges related to hypotony, associated risk factors, and hypotony management.

EXPERT OPINION

The progressive evolution of the XEN Gel constitutes a significant advancement in the field of glaucoma management. Comparative studies investigating diverse implantation methodologies, particularly the ab interno and closed conjunctival approaches, highlight the device versatility in addressing individual patient needs. Exploring hypotony from both statistical and clinical perspectives challenges the traditional view of intraocular pressure as a straightforward success or failure indicator. The incidence of hypotony-related issues varies between device models, emphasizes the need for an individualized approach during device selection. Overall, understanding the dynamics of hypotony is crucial for optimizing the outcomes of XEN Gel implantation.

XEN®-45 implantation for refractory uveitic glaucoma

PURPOSE

To evaluate the efficacy of XEN®-45 gel stent ab interno implantation for medically uncontrolled uveitic glaucoma.

METHODS

Retrospective analysis of 25 eyes receiving XEN® gel stent for medically uncontrolled uveitic glaucoma from February 2019 to February 2023 with recording of intraocular pressure (IOP) values, ocular hypotensive medication, requirement for revision or secondary surgery and complications. Prerequisites for XEN® implantation were a clear cornea, an open iridocorneal angle and an unscarred, mobile conjunctiva at the implantation site. Minimum follow-up required for inclusion was 3 months. The primary outcome measure was IOP compared to baseline. Complete and qualified success were defined as final IOP of ≤ 18 mmHg without or with topical antiglaucomatous treatment, respectively. Failure was defined as IOP > 18 mmHg on two consecutive visits, IOP reduction < 20%, persisting complications from hypotony and open conjunctival bleb revision. Further glaucoma surgical intervention was defined as complete failure.

RESULTS

Mean preoperative IOP was 35.3 ± 10.9 mmHg on 2.9 ± 0.9 topical antiglaucomatous agents. 19 of 25 patients (76%) received additional oral acetazolamide. 19 eyes were pseudophakic, 5 eyes phakic and 1 aphakic. Early postoperatively, mean IOP reduced to 7.7 ± 3.0 mmHg (75.8% reduction). At final follow-up (mean 17.7 months) mean IOP was 12.0 ± 3.8 mmHg (62.5% reduction) on 0.2 ± 0.6 medications. Six eyes (24%) required bleb revision at mean 28 weeks and therefore were categorized as failure. One eye failed despite bleb revision and restart of topical ocular hypotensive medication. Three other eyes (12%) had IOP spikes with uveitis flare-ups. Transient hypotony complications occurred in 32%. At final follow-up, 18 eyes (72%) achieved complete success and one eye (4%) qualified success.

CONCLUSION

The XEN® gel stent effectively reduced IOP in uncontrolled uveitic glaucoma, with 72% complete success. Bleb revision was required in 24%. IOP spikes occurred in 12% despite functioning blebs. Further follow-up is needed to determine long-term outcomes.

XEN-45 in the management of early glaucoma surgery: A national Delphi consensus study

BACKGROUND AND OBJECTIVE

Recommendations on general glaucoma management and the use of early minimally invasive and microincisional surgeries are limited. This study aimed to establish consensus regarding glaucoma management, focusing on the XEN-45 gel stent implant.

METHODS

A Delphi consensus-driven process was used. The scientific committee led the study, identified the expert panel, and participated in elaborating the questionnaire. Fifty-one panelists were invited to complete, on a nine-point Likert scale, an 89-item questionnaire covering three topic blocks. Two Delphi rounds were performed. Consensus was achieved if ≥66.6% of panelists reached agreement or disagreement.

RESULTS

Panelists agreed on 84 items related to the patients' quality of life, the therapeutic algorithm and patient profile, and surgical and pre- and post-operative management. Panelists agreed on the suitability of XEN stent implants to treat glaucoma at different stages and for different patient profiles: young patients, elderly or with significant comorbidities, and with myopic glaucoma, patients who failed previous surgeries, and with previous poor post-operative experience. XEN surgery was considered a therapeutic step prior to classic filtering surgery and a possible first surgical option in elderly patients with comorbidities and uncontrolled intraocular pressure. XEN surgery allows the patient to return to routine daily activities faster than conventional filtering surgeries and to reduce and/or eliminate topical treatments.

CONCLUSIONS

This Delphi-driven consensus resulted in a series of general recommendations for glaucoma management, including those related to patient quality of life, therapeutic algorithm, and patient profile, and specific ones regarding the use of XEN stent gel surgery.

Factors Associated with the Efficacy of XEN Gel Implant

INTRODUCTION

Microinvasive glaucoma surgery (MIGS) is a growing trend, and XEN gel implant is one of the most effective types of MIGS. This study aimed to examine factors associated with the surgical success of XEN gel implants.

METHODS

This retrospective cohort study enrolled patients with glaucoma receiving XEN implantation alone or combined with phacoemulsification (PHACOXEN) with a follow-up period of more than 6 months at Hualien Tzu Chi Hospital, Taiwan. If intraocular pressure (IOP) elevated above 20 mmHg during the follow-up, needling or open revision was performed. The primary outcome measures included IOP and the number of glaucoma medications.

RESULTS

Male patients had lower postoperative IOP; male patients and higher preoperative IOP were associated with higher IOP change rates, and older patients had a higher chance of achieving IOP < 18 mmHg and being medication-free at months 12, 24, and 36. The Kaplan-Meier curve showed that the probability of free-of-rescue intervention over the follow-up period was not different between the XEN alone and the PHACOXEN group (P = 0.859). Both needling and open revision were effective rescue interventions, but open revision had a higher chance of achieving IOP ≤ 18 mmHg and being medication-free (P = 0.031) and required less medication afterward (P = 0.044). Older age (P = 0.013) and male patients (P = 0.022) had a lower IOP after rescue interventions. Compared with open revision, needling was associated with higher IOP (P = 0.048) and more required medications (P = 0.048).

CONCLUSIONS

XEN alone and PHACOXEN had comparable surgical outcomes, whereas open revision had a better IOP lowering effect than needling as a rescue intervention. Male and older patients had better surgical results in primary XEN implantations and rescue interventions.

Effectiveness and safety of XEN45 implant over 12 months of follow-up: data from the XEN-Glaucoma Treatment Registry

OBJECTIVES

To evaluate the 1-year effectiveness and safety of the XEN45, either alone or in combination with phacoemulsification, in glaucoma patients.

METHODS

This multicentre, prospective, observational study included consecutive eyes of glaucoma patients from the Italian XEN-Glaucoma Treatment Registry (XEN-GTR) who underwent XEN45 alone or in combination with phacoemulsification, with at least 1 year of follow-up. Surgical success was defined as intraocular pressure (IOP) < 18 mmHg and ≥20% reduction from preoperative IOP, over 1 year of follow-up.

RESULTS

Two hundred thirty-nine eyes (239 patients) were analyzed, 144 (60.2%) eyes in the XEN-solo and 95 (39.8%) eyes in the XEN+Phaco groups. One hundred-sixty-eight (70.3%) eyes achieved overall success, without statistically significant differences between study groups (p = 0.07). Preoperative IOP dropped from a median (IQR) of 23.0 (20.0-26.0) mmHg to 14.0 (12.0-16.0) mmHg at month 12 (p < 0.001), with overall 39.9 ± 18.3% IOP reduction. The mean number of preoperative ocular hypotensive medications (OHM) was significantly reduced from 2.7 ± 0.9 to 0.5 ± 0.9 at month 12 (p < 0.001). Preoperative IOP < 15 mmHg (HR: 6.63; 95%CI: 2.61-16.84, p < 0.001) and temporal position of the surgeon (HR: 4.25; 95%CI: 2.62-6.88, p < 0.001) were significantly associated with surgery failure. One hundred-forty-six (61.1%) eyes had no intraoperative complications, whereas 91 (38.1%) and 56 (23.4%) eyes experienced at least one complication, respectively early (< month 1) and late (≥ month 1), all self-limiting or successfully treated without sequelae. Needling occurred in 55 (23.0%) eyes at least once during follow-up.

CONCLUSION

Over 1-year follow-up, XEN45 alone or in combination with phacoemulsification, had comparable success rates and effectively and safely lowered IOP and the need for OHM.

[Review by the French Glaucoma Society on the roles of new surgical techniques in glaucoma]

The surgical management of glaucoma has been enriched in recent years by the arrival of new surgical techniques as a group known as MIGS (minimally invasive glaucoma surgery). The objective of these new techniques is to reduce intraocular pressure (IOP) while limiting the risk of complications of conventional filtering surgery and allowing faster visual recovery. MIGS can be classified into three main categories depending on the route used to promote the outflow of aqueous humor: the trabecular route, the suprachoroidal route and the subconjunctival route. MIGS using the subconjunctival route are also called minimally invasive bleb surgery (MIBS). These new techniques do not replace conventional filtering surgery, which remains the gold standard technique, but now offer new alternatives for the surgical management of glaucoma patients in combination with cataract surgery or as stand-alone procedures.

Minimally Invasive Glaucoma Surgery: Latest Developments and Future Challenges

The development of minimally invasive glaucoma surgeries (MIGSs) was intended to provide safe and modestly efficacious modalities for early intervention of mild-to-moderate glaucoma, with minimal trauma and rapid recovery. They were mainly ab interno procedures that reduce intraocular pressure by facilitating the aqueous outflow by bypassing the trabecular meshwork resistance, reinforcing the uveoscleral flow via the supraciliary space, and reducing aqueous production by the ciliary body. While the cumulating evidence helps shape the role of the available MIGS, the exponential new development and advancement in this field has expanded the territory of MIGS. Apart from developing subconjunctival MIGS filtration devices (Xen gel stent and PRESERFLO MicroShunt), there is a tendency to revisit the "traditional" MIGS for alternative use and to modify the procedures with consideration of the fundamental aqueous outflow physiology. Combined MIGS has also been suggested, based on the theory that their different mechanisms may provide additive or synergistic effects. The advancement of laser procedures is also promising and could supplement unmet needs along the glaucoma treatment algorithm. This review examines the broad array of MIGS, updates the recent findings, discusses their potential alternative applications, and explores future challenges.

XEN 45 Gel Stent Implantation in Open Angle Glaucoma: 5-Year Results of a Prospective Study

PRCIS

XEN 45 Gel Stent is safe and effective for 3 years. The study results provide useful insight into the outcome of XEN 45 Gel Stent surgery over 5 years in daily clinical practice.

PURPOSE

To evaluate 5-year outcomes of XEN 45 gel stent implantation (XEN) in patients with open angle glaucoma.

METHODS

This is a prospective, single-center, interventional study. XEN implantation either alone (XEN) or combined with phacoemulsification (Phaco + XEN) was performed on 170 consecutive eyes (126 patients) with uncontrolled intraocular pressure (IOP) or disease progression despite medical treatment. "Complete" surgical success at 60 months was defined as unmedicated IOP ≤15 mm Hg and a relative IOP reduction ≥20% from medicated baseline, while "qualified" success allowed fewer ocular hypotensive medications than at baseline. Other definitions of success with various IOP targets were also analyzed. Secondary outcomes included mean IOP and IOP-lowering medication changes and rates of reoperations.

RESULTS

Mean age was 78.1±9.2 years, and 70.3% were female. Mean medicated IOP decreased from 19.8±7.7 mm Hg [19.6±7.1 (XEN) vs. 19.8±7.0 mm Hg (Phaco+XEN)] at baseline to 12.6±3.1 mm Hg [12.5± 3.1 (XEN) vs. 12.6±3.1 (Phaco+XEN)] at 5 years (-37.0%; P < 0.001). Medications decreased from 2.0±1.3 [2.0±1.3 (XEN) vs. 2.0±1.3 (Phaco+XEN)] to 0.8±1.1 [0.8±1.1 (XEN) vs. 0.8±1.1 (Phaco + XEN)] (-60%; P <0.001). Needling was performed in 84 eyes (49%), and 19.4% underwent a secondary surgical intervention. Complete success at 3 years was a strong predictor of success at 5 years (odds ratio: 3.06, P <0.01), while needling was associated with higher rates of failure (odds ratio: 3.6, P <0.01).

CONCLUSIONS

At 5 years, XEN gel stent implantation was a safe procedure and achieved clinically meaningful IOP and medication reduction. Success at 3 years is a predictor of success at 5 years. Needling correlates with higher failure rates.

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.

New XEN63 Gel Stent Implantation in Open-Angle Glaucoma: A Two-Year Follow-Up Pilot Study

Purpose

The XEN gel stent was developed to reduce the risks of filtration surgery by standardizing the outflow of aqueous humor into the subconjunctival space. Recently, a modified version of the XEN63 gel stent was introduced. The goal of this study was to assess its efficacy and safety.

Methods

This is a prospective, nonrandomized, observational, consecutive case series study at a single tertiary centre. Patients with open-angle glaucoma with above target intraocular pressure (IOP) despite maximal tolerated medication were included. The primary outcome was a change of median IOP. Secondary outcomes included a change in the number of medications, complete success, needling and complication rates. Success was defined as a lowering of IOP > 20% from baseline and IOP ≤ 14 mmHg. Complete success indicated that the target IOP was reached without medications.

Results

Six patients were included. The median IOP decreased from 35.5 mmHg (25.0-40.0 mmHg) at baseline to 11.5 mmHg (4.0-15.0 mmHg, p = 0.03), and median IOP-lowering medication was reduced from 4.0 (3.0-4.0) at baseline to 0 (0-1.0, p = 0.03) after two years. Five patients (83.0%) had a complete success after two years. Two patients (33.0%) required a needling procedure. Three patients (50.0%) required an intervention due to symptomatic hypotony within the first three weeks postoperatively. Hypotony resolved completely or was asymptomatic after three months.

Conclusion

Our study demonstrated a statistically significant reduction in both IOP and number of IOP-lowering medications. Complications were well manageable and had no long-term sequelae.

Gel Stent Versus Trabeculectomy: The Randomized, Multicenter, Gold-Standard Pathway Study (GPS) of Effectiveness and Safety at 12 Months

PURPOSE

To compare effectiveness and safety of the gel stent to trabeculectomy in open-angle glaucoma (OAG).

DESIGN

Prospective, randomized, multicenter, noninferiority study.

METHODS

Patients with OAG and intraocular pressure (IOP) 15 to 44 mm Hg on topical IOP-lowering medication were randomized 2:1 to gel stent implantation or trabeculectomy. Primary end point (surgical success): percentage of patients at month 12 achieving ≥20% IOP reduction from baseline without medication increase, clinical hypotony, vision loss to counting fingers, or secondary surgical intervention (SSI) in a noninferiority test with 24% margins. Secondary end points (month 12) included mean IOP and medication count, postoperative intervention rate, visual recovery, and patient-reported outcomes (PROs). Safety end points included adverse events (AEs).

RESULTS

At month 12, the gel stent was statistically noninferior to trabeculectomy (between-treatment difference [Δ], -6.1%; 95% CI, -22.9%, 10.8%); 62.1% and 68.2% achieved the primary end point, respectively (P=.487); mean IOP and medication count reductions from baseline were significant (P<.001); and the IOP change-related Δ (2.8 mm Hg) favored trabeculectomy (P=.024). The gel stent resulted in fewer eyes requiring in-office postoperative interventions (P=.024 after excluding laser suture lysis), faster visual recovery (P≤.048), and greater 6-month improvements in visual function problems (ie, PROs; P≤.022). The most common AEs were reduced visual acuity at any time (gel stent, 38.9%; trabeculectomy, 54.5%) and hypotony (IOP <6 mm Hg at any time) (gel stent, 23.2%; trabeculectomy, 50.0%).

CONCLUSIONS

At month 12, the gel stent was statistically noninferior to trabeculectomy, per the percentage of patients achieving ≥20% IOP reduction from baseline without medication increase, clinical hypotony, vision loss to counting fingers, or SSI. Trabeculectomy achieved a statistically lower mean IOP, numerically lower failure rate, and numerically lower need for supplemental medications. The gel stent resulted in fewer postoperative interventions, better visual recovery, and fewer AEs.

XEN®-63 Compared to XEN®-45 Gel Stents to Reduce Intraocular Pressure in Glaucoma

The XEN® gel stent reduces intraocular pressure (IOP) in glaucoma. XEN®-45 is widely used; the newer XEN®-63 has a larger lumen targeting potentially lower IOP outcomes. We retrospectively compared the first 15 XEN®-63 cases to 15 matched XEN®-45 controls. With a preoperative IOP of 18.1 ± 3.9 mmHg (mean ± SD) and a final IOP of 9.1 ± 2.0 mmHg, XEN®-63 implantation resulted in an IOP reduction of 44.6 ± 16.5%. Similarly, with a preoperative IOP of 18.3 ± 4.5 mmHg and a final IOP of 10.3 ± 2.1 mmHg, XEN®-45 implantation resulted in an IOP reduction of 40.1 ± 17.2%. The median follow-up period was 204 days (range 78-338 days) for the XEN®-63 group and 386 days (range 99-1688 days) for the XEN®-45 group. In total, 5/15 eyes of each group underwent open conjunctival bleb revision within the period of observation. Three eyes of the XEN®-63 group had secondary glaucoma surgery. One eye in the XEN®-63 group and three eyes in the XEN®-45 group required a restart of antiglaucomatous medication. In conclusion, both stents effectively lower IOP and medication. XEN®-63 achieved a slightly lower IOP over a short follow-up. Complication and revision rates were similar.

Four-Year Outcome of XEN 45 Gel Stent Implantation in a Swedish Population

Purpose

To report the long-time success rate of XEN 45 gel stent implantation in a Scandinavian population.

Patients and Methods

This was a retrospective single-center analysis of all patients undergoing XEN 45 stent surgery between December 2015 and May 2017. The main outcome was success rate according to several definitions of success. Subgroup analysis was performed. Secondary outcomes were change in intraocular pressure (IOP) and number of IOP-lowering agents. Need for secondary glaucoma surgery, needling rate and complications were recorded.

Results

A total of 103 eyes could be evaluated after four years. Mean age was 70.6 years. Primary open-angle glaucoma (POAG) accounted for 46.6% and exfoliative glaucoma (PEXG) for 39.8%. Mean IOP dropped from 24.0 to 15.9 mmHg (p<0.001) and IOP-lowering agents from 3.5 to 1.5 (p<0.001). The success rate with individual target pressures after four years was 43.7%. Secondary glaucoma surgery was performed in 45 (43.7%) of cases. Combined cases (n=12) were not statistically different to stand-alone procedures (p=0.28). No difference between PEXG and POAG could be detected (p=0.44). During the learning curve, stent misplacement was common and resulted in worse outcome for less experienced surgeons.

Conclusion

The overall success rate of XEN 45 gel stent surgery in the present cohort is relatively low in a long-time follow-up under the given circumstances if all initial patients are included to follow-up. The influence of the surgeon's learning curve is obvious, and improvement in success can be expected when used by experienced and high-volume surgeons. No significant differences were found in PEXG compared to POAG or in XEN surgery combined with cataract surgery compared to stand-alone.

Long-Term Effectiveness of XEN 45 Gel-Stent in Open-Angle Glaucoma Patients

Purpose

To assess the effectiveness of XEN45, either alone or in combination with phacoemulsification, in open-angle glaucoma (OAG) patients in clinical practice.

Methods

Retrospective and single-center study conducted on OAG patients who underwent XEN45 implant, either alone or in combination with cataract surgery. We compared the clinical outcomes of the eyes of thosewho underwent XEN-solo versus those who underwent XEN+Phacoemulsification. The primary endpoint was the mean change in intraocular pressure (IOP) from baseline to the last follow-up visit.

Results

A total of 154 eyes, 37 (24.0%) eyes that underwent XEN-solo and 117 (76.0%) eyes that underwent XEN+Phacoemulsification, were included. The mean preoperative IOP was significantly lowered from 19.1±5.0 mmHg to 14.9±3.8 mmHg at month-36, p<0.0001. Preoperative IOP was significantly lowered from 21.2±6.2 mmHg and 18.4±4.3 mmHg to 14.3±4.0 mm Hg and 15.2±3.7 mmHg at month-36 in the XEN-solo and XEN+Phacoemulsification groups, p<0.0004 and p=0.0009; with no significant differences between them. In the overall study population, the mean number of antiglaucoma medications was significantly reduced from 2.1±0.8 to 0.2±0.6, p<0.0001. There were no significant differences in the proportion of eyes with a final IOP ≤14 mmHg and ≤16 mmHg between XEN-solo and XEN+Phaco groups (p=0.8406 and 0.04970, respectively). Thirty-six (23.4%) eyes required a needling procedure.

Conclusion

XEN implant significantly lowered IOP and reduced the need of ocular hypotensive medication, while maintaining a good safety profile. Beyond week-1, there were no significant differences in IOP lowering between XEN-solo and XEN+Phacoemulsification groups.

[Comparison of new and old procedures in glaucoma surgery : Trabeculectomy, Preserflo and XEN]

Glaucoma is one of the most frequent causes of irreversible blindness worldwide. The main risk factor of the disease is an individually too high intraocular pressure and pressure reduction is still the only established treatment. If conservative pressure reduction and adherence are insufficient, and if the patient is unable to tolerate conservative treatment, surgical procedures become necessary. There are nowadays more than a dozen different surgical procedures for lowering the pressure. This article presents and discusses the procedures that have a subconjunctival pre-equatorial drainage in common. These include trabeculectomy, the XEN-gel implant and the Preserflo microshunt.

Glaucoma medical treatment as a predictor of XEN45 subconjunctival gel implant hypotensive efficacy

PURPOSE

The aim of this study was to determine the preoperative characteristics influencing hypotensive efficacy of the XEN45 gel stent in patients with open-angle glaucoma at one-year follow-up.

MATERIALS AND METHODS

This was a retrospective multicentre study. All patients who underwent XEN45 gel stent implantation between January 2017 and January 2021 were included. The main study outcome was the assessment of one-year postoperative intraocular pressure (IOP) and glaucoma medication differences according to the number and type of preoperative topical treatments or glaucoma surgery, glaucoma stage and time since diagnosis. Follow-up period was 1-year post-surgery in all cases. IOP reduction and surgery success (not requiring reoperation or pressure failures [IOP > 18 mmHg and < 20% reduction in IOP]), safety and cost savings in topical glaucoma therapy after surgery were secondarily assessed. Linear regression analysis to determine the preoperative parameters influence on 1-year postoperative results was performed.

RESULTS

XEN45 gel stent was implanted in 85 patients. One-year postoperative mean IOP dropped from 20.6 ± 4.1 to 13.7 ± 2.8 mmHg (p < 0.0001). Likewise, mean number of topical treatments decreased from 2.05 ± 0.9 to 0.36 ± 0.65 (p < 0.001). Both were mainly influenced by the number of preoperative glaucoma treatments, such that for each one-glaucoma medication increase, postoperative intraocular pressure increased by 1.18 mmHg (95% CI 0.56-1.79, p < 0.0001) and number of glaucoma medications increased by 0.3 (95% CI 0.16-0.43, p < 0.001). Overall success rates (with and without supplemental glaucoma medication use) were 97.6% (95% CI 94.5-100%), 87.1% (95% CI 80.2-87.1%) and 61.2% (95% CI 51.6-72.5%) at 3, 6 months and 1 year after surgery. No sight-threatening adverse events were reported. Mean annual cost savings on medical treatment since surgery reached EUR 251.19 ± 169. 93 euros.

CONCLUSIONS

One year after surgery, XEN45 gel implant significantly reduced IOP and number of topical medications with an adequate safety profile being both mainly influenced by the number of preoperative glaucoma treatments.

Novel Bleb Classification Following Ab Interno Implantation of Gel-Stent Using Anterior Segment Optical Coherence Tomography

PRCIS

A novel qualitative tomographical classification for bleb after implantation of XEN-Gel-Stent using ab interno approach is presented. Association of anatomic patterns to intraocular pressure (IOP) and success rates (SR) illustrates that anterior segment optical coherence tomography can be useful tool in clinical guidance.

PURPOSE

To present a novel classification of bleb resulting from ab interno implantation of XEN-Gel-Stent and report association of tomographical patterns with IOP and SR.

MATERIALS AND METHODS

A cross-sectional 1-armed study of patients receiving XEN-Gel-Stent. Tomographical changes in the bleb area were studied using swept-source optical coherence tomography in an early (d 29-90 postsurgery) and late (starting from d 91 postsurgery) phase. Frequency of patterns and their association with IOP and SR (defined as IOP<18 mmHg without medications) were studied.

RESULTS

One hundred eleven examinations of 49 blebs (49 patients) were included. Three tomographical patterns at conjunctival, 4 at tenons capsule, and 2 at episcleral level were characterized. Most frequent conjunctival pattern was subconjunctival spaces (56.3% and 53.2% in the early and late phase, respectively) and associated with lower IOP (13.0±6.0 mmHg) and higher SR (89%) but only in the early phase compared with other conjunctival patterns ( P <0.05). At tenons capsule level, the hyporeflective pattern was most frequent (50% and 51.9% in early and late phase) followed by the cavernous pattern. Both patterns associated with lower IOP and higher SR compared with hyper-reflective or loss of tenon changes ( P <0.005). Most blebs showed no episcleral lake (87.5% and 89.9% in early and late phase). No difference of IOP and SR was noted compared with those showing an episcleral lake.

CONCLUSION

A practical and clinically relevant novel classification system is proposed to tomographically describe and classify blebs after implantation of XEN-Gel-Stent. Certain patterns were associated with lower IOP and higher SR.

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.

Devices and Treatments to Address Low Adherence in Glaucoma Patients: A Narrative Review

Poor adherence to topical glaucoma medications has been linked to worse visual field outcomes in glaucoma patients. Therefore, identifying and overcoming the adherence barriers are expected to slow down the progression of disease. The most common barriers to adherence, in addition to the lack of knowledge, include forgetfulness, side effects of medications, difficulties with drop instillation and low self-efficacy. Symptoms and signs of ocular surface disease, which importantly reduce patients' quality of life, are decreased by using preservative-free topical medications. Sustained drug delivery systems using different vehicles seem promising for relieving the burden of drop administration. Currently, only the bimatoprost sustained-release intracameral implant is available for clinical use and single administration. In the era of digitalization, smart drug delivery-connected devices may aid adherence and, by sharing data with care providers, improve monitoring and adjusting treatment. Selective laser trabeculoplasty as first-line treatment delays the need for drops, whereas minimally invasive glaucoma procedures with and without devices combined with cataract surgery increase the likelihood of patients with early-to-moderate glaucoma to remain drop free or reduce the number of drops needed to control intraocular pressure. The aim of this narrative review is to present and discuss devices and treatments that may improve adherence by reducing the need for drops and side effects of medications and aiding in glaucoma monitoring. For the future, there is a need for studies focusing on clinically important outcomes, quality of life and the cost of intervention with longer post-interventional follow up.

Minimally Invasive Glaucoma Surgery: Safety of Individual Devices

Primary open-angle glaucoma progression in those already on maximal medical therapy has traditionally been treated with trabeculectomy, a surgical procedure that carries a high degree of morbidity. In the last few decades, significant advances have been made in the field of minimally invasive glaucoma surgery (MIGS) devices, which aim to defer or prevent trabeculectomy via less arduous surgical techniques in certain types of glaucoma. Although reviews have been published examining the efficacy of various MIGS techniques, no article synthesises the comparative safety of all available devices. We performed a literature review examining the safety of MIGS devices. Fifteen devices were included, variously attempting to increase aqueous outflow through the trabecular meshwork or the suprachoroidal space, shunting into the subconjunctival space, or reducing aqueous production through ciliary body ablation. Notably, the earliest product attempting to increase outflow to the suprachoroidal space, Alcon's CyPass Micro-Stent, was withdrawn from the market due to concerns regarding increased corneal endothelial cell loss at five years post-implantation. All other devices were described as well-tolerated, with the most common adverse effects including hyphaema, intraocular pressure spikes, and device migration or obstruction. MIGS devices are purported to be uniformly safe, and many studies report no statistically significant increased complications beyond those associated with cataract surgery alone. It is important to note, however, the generally poor quality of current studies, with a dearth of randomised, or even prospective, data, and a large proportion of studies funded by device producers.

XEN® implantation: an effective strategy to stop glaucoma progression despite prior minimally invasive glaucoma surgery

Purpose

The aim of this study was to evaluate whether XEN® implantation is a reasonable and safe method to lower the intraocular pressure (IOP) and amount of medication for adult primary open-angle glaucoma (POAG) over a 3-year period. The influence of the type of anesthesia, previous glaucoma surgery, and postoperative interventions on the outcome were examined.

Methods

In this retrospective study, 96 eyes were included. XEN® implantation was performed as sole procedure under general (n = 86) or local anesthesia (n = 10). IOP and number of glaucoma medication were assessed preoperatively: day 1, week 6, month 3, 6, 12, 24, and 36. Further outcome parameters were Kaplan–Meier success rates, secondary intervention, and complication rates.

Results

IOP decreased from 20.7 ± 5.1 to 12.8 ± 2.5 mmHg at the 36-month follow-up (p < 0.001) and glaucoma therapy was reduced from 3.3 ± 0.8 to 1.2 ± 1.6 (36 months, p < 0.001). Transient postoperative hypotony was documented in 26 eyes (27.1%). General anesthesia resulted in a significant improvement of the survival rate compared to local anesthesia (77% vs. 50%, p = 0.044). Prior iStent inject®, Trabectome®, or SLT laser had no significant impact, such as filter bleb revision. The number of postoperative needlings had a significantly negative influence (p = 0.012).

Conclusion

XEN® implantation effectively and significantly lowers the IOP and number of glaucoma therapy in POAG in the 36-month follow-up with a favorable profile of side effects and few complications. In case of IOP, general anesthesia has a significant positive influence on the survival rate, whereas prior SLT or MIGS does not have significant impact.

3-year Outcomes of XEN Implant Compared to Trabeculectomy, With or Without Phacoemulsification for Open-angle Glaucoma

PRCIS

Trabeculectomy surgery reduces the intraocular pressure (IOP) more than the XEN45 implant over 3 years. There is no difference in the number of antiglaucoma medications between the two procedures. The decision to perform either trabeculectomy or XEN45 implantation must be evaluated on a case-by-case basis, taking into account the high rate of needling of the XEN45.

PURPOSE

The aim of this study was to compare the differences between the efficacy and safety of the XEN45 implant and trabeculectomy (TRAB), either alone or in combination with phacoemulsification (PHACO), in patients with open-angle glaucoma (OAG) at 36 months.

METHODS

A retrospective, single-center and comparative study conducted on OAG patients that underwent XEN45 implantation or trabeculectomy from 2016 to 2018. Patients were divided into four groups: group 1 (XEN45 alone); group 2 (XEN45+PHACO); group 3 (TRAB alone); group 4 (TRAB+PHACO). For statistical purposes, groups 1 and 2 were combined (XEN45 implant), while groups 3 and 4 were also combined (TRAB surgery). Intraocular pressure (IOP), number of antiglaucoma medications (NOAM) and adverse events were evaluated. The main outcome measure was the reduction in IOP at 36 months postoperatively.

RESULTS

One hundred and thirty-four patients (134 eyes; 63 XEN45 and 71 TRAB) were included. The mean (95% CI) IOP reduction at the end of the study follow-up was-6.3 (-11.0 to -1.6 mmHg, P=0.025, XEN45 alone),-8.9 (-11.0 to-6.8 mmHg, P<0.001, TRAB alone),-2.5 (-4.5 to -0.4 mmHg, P=0.019, XEN45+PHACO), and-5.6 (-7.7 to-3.4 mmHg, P<0.001, TRAB±PHACO). The proportion of patients achieving an IOP≥6 and≤16 mmHg without treatment at the end of the 36-month follow-up were 50.8% (32/63) in the XEN45 implant and 49.3% (35/71) in the TRAB surgery group, P=0.863. The mean number of antiglaucoma medications was significantly reduced in all the study groups. The needling rate was 19% in XEN45 versus 5.6% in the TRAB group (P=0.030), and 2.81% and 36.6% of eyes in the TRAB group presented anterior chamber (AC) flattening and hyphema, respectively.

CONCLUSIONS

Trabeculectomy surgery lowered IOP significantly more than XEN45 implant with or without phacoemulsification over 3 years and had a significantly lower need for additional needling surgery. Both procedures reduce the number of antiglaucoma medications to a similar rate. These findings are relevant to the informed consent process and patient decisions for one procedure over the other.

The efficacy of XEN gel stent implantation in glaucoma: a systematic review and meta-analysis

Background

Xen is a device for minimally invasive glaucoma surgery, and is used to treat POAG, pseudoexfoliative or pigmentary glaucoma, as well as refractory glaucoma. The efficacy of XEN in treating glaucoma remains to be confirmed and clarified. Hence, we conducted a systematic review and meta-analysis to examine the efficacy and associated complication of XEN implantations.

Methods

We conducted a literature search in PubMed, EMBASE, the Cochrane Library of Systematic Reviews, Web of Science, China National Knowledge Infrastructure, WanFang and SinoMed databases to identify studies, published before May 15, 2021, which evaluated XEN in glaucoma, and parameters for measurements included intra-ocular pressure (IOP), number of anti-glaucoma medications (NOAM), and bleb needling rate. We compared the measurements of XEN-only procedure between phaco-XEN and trabeculectomy, and we also did sub-analysis based on time points, glaucoma types, ethnics, etc. Sensitivity analyses and publication bias were conducted for evaluating bias.This study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA 2020) reporting guideline.

Results

We identified 78 eligible studies, analysis revealed obvious IOP reduction after XEN stent implantation (SMD: 1.69, 95% CI 1.52 to 1.86, p value < 0.001) and NOAM reduction (SMD: 2.11, 95% CI 1.84 to 2.38, p value < 0.001). Sub-analysis showed no significant difference with respect to time points, ethnicities, and economic status. No significant difference was found between XEN treatment effect on POAG and PEXG eyes and between pseudo-phakic and phakic eyes. Also no significant difference was found between XEN and phaco-XEN surgery in terms of IOP after surgery (SMD: -0.01, 95% CI -0.09 to 0.08, p value 0.894). However, NOAM (after publication bias correction) and bleb needling rate (RR: 1.45, 95% CI 1.06to 1.99, p value 0.019) were lower in phaco-XEN group compared to XEN only group. Compared to trabeculectomy, XEN implantation had similar after-surgery IOP, however bleb needling rate (RR: 2.42, 95% CI 1.33 to 4.43, p value 0.004) was higher.

Conclusion

Our results confirmed that XEN is effective in lowering both IOP and NOAM till 48 months after surgery. It is noteworthy that XEN implantation leads to higher needling rate, compared to phaco-XEN or trabeculectomy. Further research, studying complications of XEN on non-European ethnicities, especially on Asian, are in urgent need before XEN is widely applied.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02502-y.

Compatibility and Durability of the Gel Stent Material

INTRODUCTION

The XEN Gel Stent (AbbVie Pharmaceuticals) is a device made from Gelatin; a well-known material in the medical field that is firm enough to hold its shape and soft enough to conform to tissues and reduce the risk of erosion. The Gel Stent creates a permanent outflow connection between the anterior chamber and subconjunctival space.

AREAS COVERED

Validation testing done on the Gel Stent to evaluate biocompatibility and durability of the material as well as real-world experience are included and discussed in this paper.

EXPERT OPINION

Correlating the results of the preclinical testing, study outcomes available in the published literature, and the surgeons' experiences, the device and materials have shown to have an acceptable biocompatibility and durability profile, with a stable, nondegradable, and permanent implant.

Retrospective Analysis of 12 Months Glaucoma Implant Efficacy: XEN45 and PreserFlo Microshunt

PURPOSE

Several new implant devices have recently been introduced to glaucoma surgery using various techniques for reducing intraocular pressure (IOP). Two implants introduced during the past couple of years, XEN45 and PreserFlo Microshunt, are both designed to control subconjunctival filtration. There are two Swiss multicenter studies that collected the data retrospectively to analyze the efficacy and safety of these two devices separately. In this study, we report the analysis of the combined data subset from the University Hospital of Basel.

SUBJECTS AND METHODS

The XEN45 implantation technique was introduced to Basel University Hospital in 2016 and PreserFlo Microshunt in 2018. Sixty operated patients, thirty in each group, were operated on by one surgeon, clinically followed up, and their data retrospectively analyzed from medical records. Only standalone procedures, without combined phacoemulsification, were considered in this analysis; the lens status, however, was neither an inclusion nor an exclusion criterion. Further inclusion criteria were the diagnosis of open-angle glaucoma, no previous glaucoma surgery, other than laser trabeculoplasty, and complete medical records during the 12 months of follow-up. IOP reduction during a 12-month postoperative period was the primary outcome measure as well as the number of IOP reducing drugs. The number of subsequent surgical interventions and complications/adverse events are descriptively reported.

RESULTS

Patient age, gender, ophthalmological diagnosis, and initial preoperative IOP were well balanced between the two groups. Postoperative IOP course was comparable between the two methods for the first 12 months. IOP measurements were taken preoperatively and then on the first postop day, week 1, month 1, and months 3, 6, and 12 for the PreserFlo Microshunt vs. XEN45 (mmHg): 23.6 vs. 24.9, 9.0 vs. 8.9, 11.4 vs. 10.6, 13.0 vs.18.3, 16.8 vs.15.1, 15.9 vs.15.0, and 15.4 vs.14.5, respectively. IOP reducing medications were also comparable between the two groups. The study showed that subsequent interventions were more frequent in the XEN45 (13) than in the PreserFlo Microshunt group (7).

CONCLUSION

Both methods demonstrate satisfactory IOP control within a 12-month postoperative period with practically no serious adverse events/complications, but with relatively high numbers of subsequent interventions (needlings), particularly in the XEN45 group.

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.

Predictability of success and open conjunctival revision rates in the subsequent eye after XEN45 Gel Stent implantation according to lens status

PURPOSE

To determine the predictability of success and the risk of open conjunctival revision in the subsequent eye after XEN45 Gel Stent implantation according to lens status.

METHODS

This was a retrospective single-centre study involving 132 eyes of 66 participants who had undergone intraocular pressure (IOP)-lowering XEN45 Gel Stent implantation, either as a standalone procedure in phakic and pseudophakic eyes or in combination with phacoemulsification. Successful surgery was defined by three scores: IOP at follow-up < 21 mmHg (score A) or < 18 mmHg (score B) and an IOP reduction > 20% or IOP ≤ 15 mmHg and an IOP reduction ≥ 40% (score C). In all scores, one open conjunctival revision was allowed, and additional repeat surgery was considered a failure. The predictability of success and revision rate depending on the outcome of the first eye were calculated using Bayes' theorem.

RESULTS

IOP-lowering did not differ significantly between the first and second eyes. Success rates of standalone surgery in the second eye after successful surgery in the first eye significantly exceed rates after prior failure. For the combined procedure, the rates did not differ significantly. For score A, we determined a 76.6% chance of success following a prior success and a 57.9% chance, if prior surgery failed. The corresponding probabilities were 75% and 59.1% for score B, while 66.7% and 15.7% for score C, respectively. We calculated a 60% risk for revision surgery in the standalone phakic group. If the first eye was not revised, the risk of revision in the subsequent eye was 20%. The corresponding risks were 72.7% and 5% for the standalone procedure in pseudophakic patients and 38.4% and 41.7% for the combined procedure, respectively.

CONCLUSION

The results of our study offer a tool to predict the outcome of subsequent eye surgeries based on either the outcome in the initial eye and the type of surgery performed, owing to the high predictive potential.

Impact of failed ab-interno trabeculectomy (trabectome) on subsequent XEN45 gel stent implantation in pseudophakic eyes

PURPOSE

To determine the impact of failed ab-interno trabeculectomy on the postoperative outcome of subsequent XEN45 gel stent (Allergan, CA, USA) implantation in pseudophakic eyes.

METHODS

In this retrospective single-center study, we included 60 pseudophakic eyes from 60 participants who underwent XEN45 gel stent implantation. Thirty eyes each underwent primary stent implantation (control group) or had previously undergone a failed ab-interno trabeculectomy (trabectome group). The groups were matched at a 1:1 ratio based on the following criteria: preoperative and maximum Intraocular pressure (IOP), preoperative medication score, cup/disk-ratio, follow-up time, best-corrected visual acuity at baseline, age, and the proportion of patients classified as primary open angle glaucoma or exfoliation glaucoma. We defined a successful surgery by the following three scores: an IOP reduction > 20% and IOP at the longest follow-up < 21 mmHg (Score A) or < 18 mmHg (Score B) or IOP ≤ 15 mmHg and an IOP reduction ≥ 40% (Score C). One open conjunctival revision was allowed in all scores, and a repeat surgery was considered a failure.

RESULTS

Following an average follow-up period of 22 ± 12 months, we observed a mean IOP reduction of 38%, from 23.5 ± 5.2-14.5 ± 5.0 mmHg. Comparative analyses between the groups did not reveal a significant difference in the postoperative IOP, postoperative medication score, side effects, revision rate, repeat surgery rate, or success rate.

CONCLUSIONS

Trabectome is a viable first-line procedure for medically uncontrolled glaucoma before filtering ab-interno microstent surgery is considered.