Needling after XEN gel implant: What's the efficacy? A 1-year analysis

Anterior Segment Optical Coherence Tomography for Cases of High Intraocular Pressure Following XEN Implant for Glaucoma

PRCIS

This study showed that the XEN patency should be verified by OCT imaging in cases of encapsulated blebs. Although fibrosis plays the principal role, humor aqueous flow reduction could affect the "spacer" effect that inhibits the fibroblast attachments.

PURPOSE

To evaluate the application of the anterior segment optical coherence tomography (AS-OCT) imaging in studying the relationship between a low flow rate through the XEN63 and the development of a cystic bleb.

METHODS

Retrospective case series of 3 eyes presenting a cystic bleb after an XEN63 implantation for uncontrolled intraocular pressure (IOP). Demographic and clinical data were obtained from medical records. The imaging findings, complications, and managements following the surgery were evaluated.

RESULTS

Three patients, with an average age of 67.3 years, initially showed a patent stent lumen and a functional bleb after surgery. The IOP of all eyes increased on average at 28.3 days from the surgery, with a mean value of 39.66 mm Hg. The slit lamp examination showed a cystic bleb. The AS-OCT imaging confirmed the previous finding and revealed either a partial or total occlusion of the stent internal ostium. A Nd:YAG laser, in proximity to the ostium, was performed to resolve the obstruction. Although the AS-OCT imaging showed the device patency and the IOP immediately decreased, the latter became elevated again. Consequently, in all the cases, a further needling procedure was needed to achieve an adequate IOP reduction. Six months after the two-step procedure, the IOP averaged 13.33 mm Hg, the XEN63 lumens appeared cleared, and the blebs showed a functional morphology. No adverse events were observed.

CONCLUSION

The development of a cystic bleb may result from an altered balance between the flow rate through the XEN63 and the fibrosis development in the postoperative healing process. A proper follow-up based on slit lamp biomicroscopy, IOP measurement, and AS-OCT imaging is advisable to estimate and manage a cystic bleb following XEN63 implantation.

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.

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.

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.

Two-year Outcomes of XEN Implantation with Minimal Bleb Needling

Aim

Our study aims to report the 2 years outcomes of the XEN implant in a single unit, single surgeon setting with minimal bleb needling.

Methods

A retrospective cohort study was conducted. Inclusion criteria were patients who underwent implantation with a XEN device between May 2016 and December 2017. This included patients who underwent both combined phacoemulsification and intraocular lens implantation alongside XEN implantation and those who underwent XEN implantation alone. Data gathered included basic demographic data, best-corrected visual acuity (LogMAR), intraocular pressure (IOP) in mm Hg, mean deviation from their visual field test, and the number of IOP-lowering medications they were on. This information was recorded for their preoperative visit, and then at 6, 12, 18 and 24 months postoperatively. The primary outcome assessed was a complete success when the patient was without glaucoma medications and had an IOP of 18 mm Hg or less, but more importantly, this also had to equate to a 20% reduction in IOP compared to baseline. Qualified success was defined as the same change in IOP but with medications. Surgical failure is defined as those who required additional glaucoma surgery or those who did not obtain an IOP of 18 mm Hg alongside a 20% reduction in IOP compared to baseline.

Results

At 24 months follow-up 82.5% of patients were surgical successes. Complete surgical success was achieved in 27% of patients. Qualified surgical success was achieved in 55.6% of patients. Subgroup analysis of those undergoing XEN implantation on its own and those combined with phacoemulsification + IOL were similar. The rate of bleb needling was low at 4.5%. Complication rates were acceptable at 9.5%.

Conclusion

It is possible to get good IOP control with minimal postoperative bleb needling in patients who have undergone XEN implantation. Similar success rates are found in those undergoing combined procedures.

Clinical Significance

Bleb needling carries its own risks. Minimizing the number of bleb needling allows procedures to be reserved at a later date. Furthermore, our study shows that success rates are not affected by doing a combined procedure with phacoemulsification.

How to cite this article

Ali ZC, Moshin N, Hakim MT, et al. Two-year Outcomes of XEN Implantation with Minimal Bleb Needling. J Curr Glaucoma Pract 2022;16(2):79-83.

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.