Efficacy of the XEN-Implant in Glaucoma and a Meta-Analysis of the Literature

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.

Inferior implant of XEN63 Gel stent in a refractory open-angle glaucoma due to silicone oil tamponade: A case report

BACKGROUND

To discuss the efficacy of an inferior implant of XEN 63 gel stent in a patient with refractory glaucoma after trabeculectomy failure and vitreoretinal surgery with silicone oil tamponade.

CASE DESCRIPTION

We report the case of a 73-year-old man with a history of refractory open glaucoma with trabeculectomy failure. He experienced recurrent retinal detachments with silicone oil tamponade, with uncontrolled intra-ocular pressure (IOP) after silicone oil removal. Due to the presence of oil emulsion in the anterior chamber, the chosen location for XEN 63 implantation was the infero-temporal quadrant. Mild hyphema and vitreous hemorrhage were seen post-operatively, but were self-limiting. At week 1, the intraocular pressure was 8 mmHg with a well-formed bleb seen in anterior segment optical coherence tomography (AS-OCT). At 6 month follow up, the patient maintained a IOP of 12 mmHg without topical hypotensive drugs. Slit lamp examination revealed a widespread, developed bleb with no signs of inflammation.

CONCLUSION

In this case of refractory glaucoma in a vitrectomized eye with previous oil tamponade, the inferior placement of the XEN 63 gel stent delivered an adequate intraocular pressure even at 6-months follow up, with a diffuse functional infero-nasal bleb seen with AS-OCT.

Microfluidics in the eye: a review of glaucoma implants from an engineering perspective

Glaucoma is a progressive optic neuropathy in the eye, which is a leading cause of irreversible blindness worldwide and currently affects over 70 million individuals. Clinically, intraocular pressure (IOP) reduction is the only proven treatment to halt the progression of glaucoma. Microfluidic devices such as glaucoma drainage devices (GDDs) and minimally invasive glaucoma surgery (MIGS) devices are routinely used by ophthalmologists to manage elevated IOP, by creating an artificial pathway for the over-accumulated aqueous humor (AH) in a glaucomatous eye, when the natural pathways are severely blocked. Herein, a detailed modelling and analysis of both the natural microfluidic pathways of the AH in the eye and artificial microfluidic pathways formed additionally by the various glaucoma implants are conducted to provide an insight into the causes of the IOP abnormality and the improvement schemes of current implant designs. The mechanisms of representative glaucoma implants have been critically reviewed from the perspective of microfluidics, and we have categorized the current implants into four groups according to the targeted drainage sites of the AH, namely Schlemm's canal, suprachoroidal space, subconjunctival space, and ocular surface. In addition, we propose to divide the development and evolution of glaucoma implant designs into three technological waves, which include microtube (1st), microvalve (2nd) and microsystem (3rd). With the emerging trends of minimal invasiveness and artificial intelligence in the development of medical implants, we envision that a comprehensive glaucoma treatment microsystem is on the horizon, which is featured with active and wireless control of IOP, real-time continuous monitoring of IOP and aqueous rate, etc. The current review could potentially cast light on the unmatched needs, challenges, and future directions of the microfluidic structural and functional designs of glaucoma implants, which would enable an enhanced safety profile, reduced complications, increased efficacy of lowering IOP and reduced IOP fluctuations, closed-loop and on-demand control of IOP, etc.

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.

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.

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.

Efficacy of the PRESERFLO MicroShunt and a Meta-Analysis of the Literature

Background: Recent studies on the PRESERFLO MicroShunt suggest that it may be effective in lowering intraocular pressure (IOP); however, the number of studies on this device remains limited. Therefore, we assessed the efficacy of the PRESERFLO MicroShunt in patients with glaucoma and performed a meta-analysis of published results. Methods: Prospective study including all patients that underwent PRESERFLO MicroShunt surgery from 2018 onwards. Sub-analyses were performed for cataract-combined procedures. To compare our results, we performed a systematic review and meta-analysis. IOP, IOP-lowering medication and surgical complications reported in the retrieved studies were assessed. Results: A total of 72 eyes underwent PRESERFLO-implant surgery (59 as standalone procedure and 13 as cataract-combined procedure). No significant differences were found in IOP and IOP-lowering medication between both groups. The mean ± standard deviation IOP and IOP-lowering medications of both groups taken together declined from 21.72 ± 8.35 to 15.92 ± 8.54 mmHg (p < 0.001, 26.7% reduction) and 3.40 to 0.93 (p < 0.001, 72.6% reduction) at 1 year follow-up, respectively. Secondary surgeries were required in 19.4% of eyes, the majority (71.4%) within 6 months. The meta-analysis including 14 studies (totaling 1213 PRESERFLO MicroShunt surgeries) from the systematic review showed a mean preoperative IOP and IOP-lowering medication of 22.28 ± 5.38 and 2.97 ± 1.07, respectively. The three-years postoperative pooled mean was (weighted mean difference, 95% CI) 11.07 (10.27 [8.23−12.32], p < 0.001) mmHg and 0.91 (1.77 [1.26−2.28], p < 0.001) for IOP and IOP-lowering medication, respectively. The most common reported complication was hypotony (2−39%). Conclusion: The PRESERFLO MicroShunt is effective and safe in lowering IOP and the number of IOP-lowering medications.

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.

XEN® 63 gel stent to treat a refractory uveitic glaucoma: A case report

PURPOSE

To describe the effectiveness of the XEN^® 63 gel stent in a refractory uveitic glaucoma after failure of an Ahmed Glaucoma Valve.

CASE DESCRIPTION

We report the case of a 54-year-old man with a history of uveitic glaucoma on his left eye due to Fuchs heterochromic iridocyclitis and neovascular glaucoma after a central retinal vein occlusion. Pre-operative intraocular pressure was 30 mmHg despite a QD (once-daily) dosed bimatoprost 0.3 mg and timolol 5 mg topical medication. At week 1, the eye exam showed an intraocular pressure of 6 mmHg with a well-formed bleb, a very mild hyphema and a localized choroidal detachment. At month 1, intraocular pressure was 14 mmHg with a formed bleb. Both hyphema and choroidal detachments had resolved. After a year, intraocular pressure was 16 mmHg without any medication and the bleb was still well-formed.

CONCLUSION

The XEN^® 63 gel stent provides a good intraocular pressure reduction and can be an efficient alternative for tube and filtration surgery in refractory glaucoma. Its long-term effectiveness needs to be evaluated.

Efficacy and Safety of Micropulse Transscleral Cyclophotocoagulation

Background: Early studies have shown that micropulse transscleral cyclophotocoagulation (MP-TSCPC) might be an effective and safe treatment option for lowering intraocular pressure (IOP). These studies were, however, somewhat limited, in particular by their retrospective nature and the length of follow-up. Therefore, we assessed the efficacy and safety of this novel treatment in a large cohort for up to 4 years. Methods: We performed a prospective cohort study, including all patients who were treated with MP-TSCPC since November 2017. The primary outcome was a reduction of IOP and the number of IOP-lowering medications. Results: The mean ± standard deviation baseline IOP and number of IOP-lowering medications were 26.6 ± 10.8 mmHg and 3.3 ± 1.3. IOP was reduced by 8.2 ± 7.9 (31.8% reduction), 6.9 ± 8.7 (28.1% reduction), and 7.1 ± 8.4 (30.2% reduction) mmHg after 6, 12, and 24 months, respectively (p < 0.001). The mean postoperative number of IOP-lowering medications was significantly reduced after 6 months by 0.6 ± 1.5 (p = 0.002) but was not significantly different after 12 or 24 months. Oral acetazolamide was significantly reduced from 28 (29%) eyes before treatment, to 9 (9%) at the last follow-up visit (p < 0.001). No major complications were observed after treatment. Conclusions: MP-TSCPC is a safe and effective treatment option for lowering IOP, but only reduced IOP-lowering medications in the first 6 months after treatment. However, MP-TSCPC is especially effective in getting patients off oral IOP-lowering drugs.

Clinical outcomes of combined Preserflo Microshunt implantation and cataract surgery in open-angle glaucoma patients

To assess the effectiveness and safety of the Preserflo Microshunt (PMS) implantation combined with cataract surgery in open-angle glaucoma (OAG) patients. Retrospective, open-label study conducted on insufficiently controlled OAG patients, who underwent a PMS implant procedure with mitomycin-C 0.2%, either alone or in combination with cataract surgery, and were followed for at least 12 months. Success was defined as an intraocular pressure (IOP) ≤ 18 mmHg and a reduction of at least 20% without (complete) or with (qualified) hypotensive medication. Fifty-eight eyes were included in the study, 35 eyes underwent PMS alone and 23 underwent PMS + Phaco. In the overall study sample, mean IOP was significantly lowered from 21.5 ± 3.3 mmHg at baseline to 14.6 ± 3.5 mmHg at month 12 (p < 0.0001). The IOP was significantly reduced in both groups; p < 0.0001 each, respectively. Ocular hypotensive medication was significantly reduced (p < 0.0001) in both groups. No significant differences were observed in IOP lowering or medication reduction between groups. At month 12, 62.1% eyes were considered as complete success and 82.8% eyes as qualified success. The most common adverse events were device close-to-endothelium, conjunctival fibrosis, and wound leakage. PMS, either alone or in combination with phacoemulsification, may be considered as a valuable option for treating OAG patients.