Bleb Analysis Using Anterior Segment Optical Coherence Tomography and Surgical Predictors of XEN Gel Stent

Reviving XEN63 Gel Stent Patency in Uveitic Glaucoma: A Novel Approach Using 10-0 Nylon Probe

Purpose

This case report describes the possibility of XEN63 lumen obstruction at the middle of the device and emphasizes the potential to restore its flow using an ab-externo revision technique involving a 10-0 nylon suture probe, before considering more aggressive surgical interventions.

Methods

A 55-year-old female with uveitic glaucoma underwent XEN63 implantation but experienced elevated intraocular pressure (IOP) (35 mm Hg) 1 month after the operation, despite medical therapy. A flat bleb, lack of response to medication, yttrium aluminum garnet (YAG) laser treatment, and slit-lamp needling necessitated revision.

Results

An ab-externo surgical procedure was performed using a 10-0 nylon probe to release the obstruction, followed by the application of mitomycin C and removal of fibrous tissue and subconjunctival Tenon's capsule. Intraoperatively, flow was observed only after probing with the 10-0 nylon. Postoperatively, the patient's IOP decreased immediately and remained well-controlled at 2 months (8 mm Hg) without requiring further medication.

Conclusion

For patients experiencing increased inflammatory response, the XEN63 gel stent may develop deep lumen occlusion that is unresponsive to conventional treatments. This case report introduces a novel surgical technique applicable to various glaucoma devices, utilizing an ab-externo approach with a 10-0 nylon probe. The demonstrated success in reducing IOP suggests its potential as a less invasive alternative to consider before resorting to more aggressive surgical interventions.

How to cite this article

Marchese V, Randazzo V, Badalamenti R, et al. Reviving XEN63 Gel Stent Patency in Uveitic Glaucoma: A Novel Approach Using 10-0 Nylon Probe. J Curr Glaucoma Pract 2024;18(2):74-78.

Factors Correlated With Mid-Term Morphology of Functional Blebs Following Implantation of Preserflo MicroShunt Using AS-OCT

Purpose

Evaluating bleb morphology is crucial after glaucoma filtering surgery. Advances in anterior segment optical coherence tomography (AS-OCT) allow for objective assessment. While various parameters differentiate functional from failed blebs, limited information exists regarding variations within functional blebs. This study aimed to identify factors influencing morphology of functional blebs following implantation of Preserflo MicroShunt.

Methods

Eyes with functional blebs after Preserflo were retrospectively included. Age, gender, lens status, preoperative intraocular pressure (pre-IOP) and number of glaucoma medications were documented along with biometric measurements as axial length (AL), white-to-white distance, and anterior chamber depth. Postoperative data included time elapsed since surgery (TaS) and postoperative IOP (post-IOP). Bleb dimensions were measured using AS-OCT including maximal bleb height (MBH), width, length (MBL), bleb wall thickness (BWT), and bleb distance to limbus (DtL) along with dimensions of episcleral lake (maximal height, width [MLW], and length). Linear regression models were applied to correlate these parameters with bleb dimensions.

Results

Included were 50 eyes from 50 patients. Mean IOP decreased from 25.3 ± 10.0 to 11.9 ± 3.0 mm Hg after 278.5 ± 221.9 days after surgery. MBH correlated negatively with age (unstandardized coefficients [uSC] = -0.012) and TaS (uSC = -0.001, P = 0.008 for both). BWT correlated negatively with age (uSC = -0.013, P = 0.02), MBL with AL (uSC = -0.566, P = 0.01) and MLW with pre-IOP (uSC = -0.073, P = 0.02). DtL exhibited a positive correlation with post-IOP (uCS = 0.136, P = 0.02).

Conclusions

Morphology of functional blebs might be influenced by multiple factors such as age, TaS, AL, and pre- and post-IOP.

Translational Relevance

Age, time after surgery, axial length, and preoperative and postoperative IOP could affect the morphology of a functional bleb; hence, these factors should be taken into consideration when making treatment decisions.

Bleb Morphology on Anterior-Segment Optical Coherence Tomography after XEN Gel Stent Implantation

We investigated the internal morphology of filtration blebs after XEN gel stent implantation using anterior segment optical coherence tomography (AS-OCT) and identified factors related to intraocular pressure (IOP) postoperatively. Eighteen eyes of 18 patients who had undergone XEN gel stent implantation were analyzed. Blebs were imaged using Visante OCT (Carl Zeiss Meditec AG, Germany) at 6 months and 1 year after surgery and evaluated for quantitative parameters including bleb height, maximum height of internal cavity, maximum bleb wall thickness, and maximum bleb epithelial thickness. Subjects were classified into two groups according to the presence or absence of a definite internal cavity between the conjunctiva and sclera using AS-OCT imaging. Nine eyes (50%) were assigned to the internal cavity group and 9 (50%) to the uniform group. Postoperative IOP was significantly lower in the internal cavity group than in the uniform group both at 6 months and 1 year after surgery (p = 0.024 and p = 0.040). Postoperative IOP showed statistically significant negative correlations with bleb height and the height of the internal cavity (Spearman correlation coefficient r = -0.518, p = 0.028 and r = -0.453, p = 0.034, respectively). AS-OCT facilitates analysis of bleb morphology after XEN gel stent implantation. A larger height of the internal cavity of the bleb appeared to correlate with lower IOP after XEN implantation.

One-Year Outcomes of Ab Externo XEN45 Gel Stent Implantation with an Open Conjunctiva Approach in Patients with Open-Angle Glaucoma

PURPOSE

This study aimed to evaluate the 1-year surgical outcomes of XEN45 gel stent implantation with an open conjunctiva approach in patients with open-angle glaucoma (OAG).

METHODS

This retrospective cohort study included 19 eyes of 19 patients who underwent XEN45 gel stent implantation with an open conjunctival approach. Surgical success was defined by intraocular pressure (IOP) ≤18 mmHg and one of the following: IOP reduction ≥30% or reduction of two glaucoma medications with final IOP if baseline IOP ≤18 mmHg. The cumulative probability of success rate was analyzed using Kaplan-Meier survival analysis. Cox proportional hazard regression analysis was used to assess prognostic factors for surgical failure.

RESULTS

IOP reduced from 32.37 ± 12.08 mmHg preoperatively to 15.14 ± 2.25 mmHg at 1 year (p = 0.001). The number of glaucoma medication reduced from 3.89 ± 0.32 preoperatively to 0.86 ± 1.35 at 1 year (p = 0.001). The success rates were 78.9% at 6 months and 73.7% at 1 year. Eyes with bleb horizontal extent ≥2 clock hours at 1 month postoperatively had a significantly higher success rate (log-rank test, p < 0.001). Greater bleb horizontal extent at 2 weeks and 1 month postoperatively was associated with a lower surgical failure rate (2 weeks: hazard ratio, 0.119; p = 0.024; 1 month: hazard ratio, 0.046; p = 0.007). Bleb needling and additional glaucoma surgeries were necessary in 10 (52.6%) and five eyes (26.3%), respectively.

CONCLUSIONS

XEN45 gel stent implantation with the open conjunctiva approach is effective in reducing IOP and glaucoma medication for over 1 year in patients with OAG.

A Comparative Analysis of Morphology and Dimensions of Functional Blebs following PRESERFLO-Microshunt and XEN-Gel-Stent, a Study Using Anterior Segment OCT

Evaluation of bleb morphology is a vital part of successful filtration glaucoma surgery. The PRESERFLO-MicroShunt (PRESERFLO) and XEN-Gel-Stent (XEN) are drainage devices implanted using different surgical approaches (ab externo and ab interno, respectively), potentially resulting in distinct bleb morphology. Understanding these morphological differences is essential for postoperative care. In this study, we retrospectively examined functioning blebs following PRESERFLO and XEN implantation using high-resolution anterior segment OCT imaging. Qualitative assessment utilizing the Jenaer Bleb Grading System and quantitative assessment measuring 12 parameters representing bleb dimensions were conducted, and the results were compared between the two groups. A total of 80 eyes from 80 patients were included (41 after PRESERFLO, 39 after XEN). Functioning blebs following PRESERFLO exhibited a higher frequency of hyperreflective tenon changes compared to XEN (31.7% vs. 10.3%, respectively, p = 0.02) and a lower frequency of cavernous changes (17.1% vs. 35.9%, p = 0.05). Additionally, PRESERFLO blebs showed a higher frequency of visible episcleral lakes (92.7% vs. 30.8%, p < 0.001). Furthermore, PRESERFLO blebs demonstrated larger height (2.13 ± 0.5 vs. 1.85 ± 0.6 mm, p = 0.03), width (10.31 ± 2.3 vs. 9.1 ± 2.3 mm, p = 0.02), length (9.13 ± 1.8 vs. 8.24 ± 1.9 mm, p = 0.04), posterior location relative to the limbus (6.21 ± 1.2 vs. 5.21 ± 1.8 mm, p = 0.005), and a thicker bleb wall (1.60 ± 0.5 vs. 1.1 ± 0.4 mm, p = 0.004). Functioning blebs following PRESERFLO and XEN displayed morphological distinctions, likely attributed to variations in surgical techniques (ab externo vs. ab interno) and stent dimensions. These morphological differences should be taken into consideration when evaluating blebs, as they could impact assessments of bleb functionality and influence decisions regarding postoperative interventions.

XEN Gel Stent for Conjunctiva with Minimal Mobility Caused by Scleral Encircling: A Case Report

This case report describes the successful use of a XEN gel stent for controlling intraocular pressure (IOP) in a patient who had previously undergone scleral encircling for rhegmatogenous retinal detachment. The patient had very limited mobile conjunctiva due to scarring caused by the earlier surgery, which limited their options for glaucoma surgery. The XEN gel stent, a minimally invasive glaucoma surgery (MIGS) procedure that does not require opening the conjunctiva, was implanted in the subconjunctival space using an ab interno approach. Postoperative blebs were imaged using anterior segment optical coherence tomography, and IOP was monitored over six months. This study found that the XEN gel stent effectively controlled the IOP, and there were no complications during or after surgery. This case report may expand the indication for the XEN gel stent, which could be considered a viable option for patients who have undergone scleral buckling and have limited mobile conjunctiva.

Efficacy and Safety of the Preserflo Microshunt With Mitomycin C for the Treatment of Open Angle Glaucoma

PRCIS

The Preserflo Microshunt (PSM) is a safe and effective glaucoma microfiltering implant that significantly reduces the intraocular pressure (IOP), either alone or in combination with phacoemulsification, during the first year after surgery.

PURPOSE

The purpose of this study was to assess the safety and efficacy of the PSM for the treatment of open angle glaucoma with 0.2 mg/mL mitomycin C, either alone or in combination with cataract surgery.

METHODS

A retrospective, open-label study of 64 eyes with primary open angle glaucoma that underwent PSM implantation and were followed up for at least 9 months. Success was defined as IOP 6-17 mm Hg and a reduction of at least 20%, complete without hypotensive medication, and qualified with medication. Safety was assessed by the incidence of adverse events. Secondary endpoints included mean hypotensive medications, visual acuity, and incidence of needling and surgical revision.

RESULTS

A total of 51 eyes underwent PSM alone and 13 underwent PSM+phacoemulsification. In the overall population of the study, the mean IOP was significantly reduced from 22.03±0.7 mm Hg at baseline to 12.7±0.4 mm Hg at the final visit, P <0.0001 (mean follow-up: 11±1.4 mo). The IOP was significantly reduced in both groups ( P <0.0001). Ocular hypotensive medication was reduced significantly from 2.7±0.7 to 0.2±0.5 ( P <0.0001). No significant differences were found in IOP-lowering medication between groups (PSM alone, 0.2±0.08; PSM+phacoemulsification, 0.1±0.1; P =0.2). At the final visit, 70.3% were considered as complete success and 12.5% as qualified success. The most common adverse event was clinical hypotony (7.8%) followed by hyphema (4.7%), and anterior chamber reformation (1.6%). Overall, 1.6% required needling and 15.6% surgical revision to restore the flow.

CONCLUSION

Glaucoma surgery with the PSM and mitomycin C was efficacious and safe in the short term, either alone or in combination with cataract surgery, and may be considered a surgical option for lowering IOP in primary open angle glaucoma.