Management of conjunctival perforation and late Seidel after XEN® surgery

Complications of XEN gel stent implantation for the treatment of glaucoma: a systematic review

Aim

This study was aimed to summarize the complications and their management associated with XEN gel stent implantation.

Methods

A systematic review of literature was conducted using Medline (via PubMed), EMBASE, the Cochrane Library databases, and China National Knowledge Infrastructure, from their inception to February 1, 2024.

Results

A total of 48 studies published between 2017 and 2024 were identified and included in the systematic review, including 16 original studies (retrospective or prospective clinical studies), 28 case reports, and 4 case series, which followed patients for up to 5 years. Early postoperative complications of XEN gel stent implantation include hypotony maculopathy (1.9-4.6%), occlusion (3.9-8.8%), suprachoroidal hemorrhage (SCH), choroidal detachment (0-15%), conjunctival erosion, and exposure of the XEN gel stent (1.1-2.3%), wound and bleb leaks (2.1%) and malignant glaucoma (MG) (2.2%). Mid-postoperative complications of XEN gel stent implantation included migration of XEN (1.5%), ptosis (1.2%), endophthalmitis (0.4-3%), macular edema (1.5-4.3%), hypertrophic bleb (8.8%) and subconjunctival XEN gel stent fragmentation (reported in 2 cases). Late postoperative complications reported in cases included spontaneous dislocation and intraocular degradation.

Conclusion

XEN gel stent implantation is a minimally invasive glaucoma surgery (MIGS) procedure for glaucoma, known for its potential to minimize tissue damage and reduce surgical duration. However, it is crucial to note that despite these advantages, there remains a risk of severe complications, including endophthalmitis, SCH, and MG. Therefore, postoperative follow-up and early recognition of severe complications are essential for surgical management.

Usefulness of the amniotic membrane graft in the management of xen® implant exposure

We report a case of a 79-year-old woman with severe glaucoma and absence of therapeutic adherence, who undergone cataract surgery and XEN® implant in her left eye. Two weeks after the intervention, conjunctival erosion was observed with exposure of the distal end of the implant, so a surgical repair was performed by combining an appositional suture of the tube, adapting its trajectory to the scleral curvature, and an amniotic membrane graft. After 6 months of follow-up, the intraocular pressure is controlled, without additional treatment needed, and no disease progression.

Minimally Invasive Glaucoma Surgery: A Critical Appraisal of the Literature

Micro- or minimally invasive glaucoma surgeries (MIGS) have been the latest addition to the glaucoma surgical treatment paradigm. This term refers not to a single surgery, but rather to a group of distinct procedures and devices that aim to decrease intraocular pressure. Broadly, MIGS can be categorized into surgeries that increase the trabecular outflow [Trabectome, iStent (first and second generations), Hydrus microstent, Kahook Dual Blade and gonioscopy-assisted transluminal trabeculotomy], surgeries that increase suprachoroidal outflow (Cypass microstent and iStent Supra), and conjunctival bleb-forming procedures (Xen gel stent and InnFocus microshunt). Compared to traditional glaucoma surgeries, such as trabeculectomy and glaucoma drainage device implantation (Ahmed, Baerveldt, and Molteno valves), MIGS are touted to have less severe complications and shorter surgical time. MIGS represent an evolving field, and the efficacy and complications of each procedure should be considered independently, giving more importance to high-quality and longer-term studies.

PreserFlo MicroShunt® exposure: a case series

BACKGROUND

PreserFlo® MicroShunt (PM) (also known as InnFocus® MicroShunt) is a subconjunctival stent implanted ab externo via a minimally invasive surgical procedure. The current indication is progressive, mild to moderate, open angle glaucoma uncontrolled on topical medications. According to the literature, adverse events are rare, mild and transient.

CASE PRESENTATION

Two cases of stand-alone PreserFlo MicroShunt® implantation in patients with uncontrolled open-angle glaucoma are reported. Exposure occurred 7 days and 3 months respectively after implantation. These cases shared common features including preexisting blepharitis and the lack of a Tenon's flap. In both cases, removal of the device was required after several attempts at repair.

CONCLUSIONS

PreserFlo MicroShunt® exposure is a potentially vision-threatening complication because of the risk of endophthalmitis. Potential risk factors include the absence of a Tenon's flap and pre-existing ocular surface inflammation. Ocular surface inflammation should be detected and treated prior to PM implantation. If a deficiency in Tenon's capsule is noted intraoperatively, close monitoring should be performed because of the higher risk of PM exposure.

Safety profile of minimally invasive glaucoma surgery

PURPOSE OF REVIEW

This article reviews the safety profile of trabecular meshwork/Schlemm's canal-based, subconjunctival, and suprachoroidal minimally invasive glaucoma surgery (MIGS).

RECENT FINDINGS

Prospective randomized clinical trials and metaanalyses published during the 2019-2020 review period provided important data regarding the safety profile of trabecular meshwork/Schlemm's canal-based MIGS. Transient hyphema and intraocular pressure spikes are among the most common complications associated with this category of MIGS, but more serious adverse events such as cyclodialysis cleft formation may also occur. Trabecular bypass microstents and the intracanalicular scaffold are further subject to device-related complications, including malposition and obstruction. Recent case reports and retrospective case series have further characterized the safety profile of the subconjunctival gel stent, with adverse events ranging from self-limited hypotony to visually devastating endophthalmitis and suprachoroidal hemorrhage. Five-year results of the COMPASS XT study demonstrated significantly greater endothelial cell loss in patients randomized to receive CyPass Micro-Stent (Alcon Laboratories, Fort Worth, TX, USA) in combination with cataract surgery versus those who underwent cataract surgery alone, and ultimately led to a Food and Drug Administration Class I recall of the device.

SUMMARY

Trabecular meshwork/Schlemm's canal-based procedures are generally among the safest MIGS, with mostly self-limited and nonvision-threatening complications. Subconjunctival gel stent insertion is associated with both bleb-related and stent-specific adverse events, which are similar to those observed with trabeculectomy and tube shunt surgery, respectively. Removal of the CyPass Micro-Stent from the market underscores the need for high-quality, long-term safety data regarding MIGS.

Laser Iridoplasty to Treat Iris-occluded XEN Gel Stent

PURPOSE

To provide the first report on argon laser peripheral iridoplasty (ALPI) to restore XEN-45 Gel stent patency after iris occlusion.

METHODS

Case description, laser technique, and relevant clinical imaging.

RESULTS

A 53-year-old African American male patient presented with progressive advanced stage primary open-angle glaucoma. Initial intraocular pressure (IOP) was 40 mm Hg, which continued to be elevated despite maximal medical therapy and selective laser trabeculoplasty. The patient underwent an uncomplicated XEN-45 Gel stent implantation and presented with an IOP of 4 mm Hg 5 days postoperatively with a functioning bleb. On postoperative day 10, the XEN lumen was found to be occluded by the iris with an IOP spike of 39 mm Hg. Anti-glaucoma treatment to induce miosis and liberate the stent was unsuccessful. ALPI was attempted to relieve the obstruction. IOP dropped to 26 mm Hg immediately post-ALPI and continued to be well-controlled 6 months later (11 mm Hg).

CONCLUSIONS

ALPI can effectively restore XEN Gel stent patency if occluded by the iris and should be considered before attempting more invasive surgical revisions.

Delayed-onset Endophthalmitis Following Implantation of a XEN45 Glaucoma Device: A Case Report

PURPOSE

The aim of this study was to present a case of delayed-onset endophthalmitis occurring after the implantation of a XEN45 device.

PATIENTS AND METHODS

The patient was a 54-year-old man with bilateral elevated intraocular pressure. The patient underwent placement of a XEN45 implant in his left eye. One month postoperatively the patient required needling with adjuvant mitomycin C. Six months later, the intraocular pressure was well controlled with treatment.

RESULTS

Eight months after surgery, the patient presented to the emergency room and was diagnosed with left eye endophthalmitis. There was no history of trauma. The presence of erosions could not be thoroughly assessed due to significant conjunctival inflammation and friability, but a scleral necrosis patch was observed around the stent's subconjunctival pathway. The vitreous culture was positive for Streptococcus oralis. The blood culture was negative, and physical examination excluded any other endogenous cause. Given the poor clinical progression, persistent site of infection, and no visual prognosis, an enucleation was performed.

CONCLUSIONS

In the case presented, we hypothesize a perforation of the conjunctiva as the most probable cause of the patient's endophthalmitis. This case, together with previous case reports, highlights the importance of periodic patient follow-up after the procedure. However, less invasive and seemingly safer new generation implants for glaucoma surgery are not fully devoid of complications.

XEN Gel Implant: a new surgical approach in glaucoma

INTRODUCTION

Glaucoma is a leading cause of blindness worldwide. Intraocular pressure (IOP) lowering is the only effective treatment strategy. Traditional glaucoma surgeries are generally considered to be unpredictable and associated with a high rate of complications. This has led to the development of a novel XEN Gel Implant, a type of minimally invasive glaucoma surgery (MIGS), lowering the IOP without extensive surgical dissection.

AREAS COVERED

A literature search was undertaken on PubMed using the terms XEN glaucoma, gelatin microstent, and MIGS. All the articles and case reports on XEN Gel Implant and selected articles on MIGS were studied and reviewed. We have discussed the results of most studies on XEN Gel Implant related to its efficacy, safety and success.

EXPERT COMMENTARY

The XEN Gel Implant effectively lowers IOP and medication use, with a favorable safety profile. Long-term data on its success and cost-effectiveness are lacking. The studies have shown it to be without any serious adverse events and to have good safety profile encouraging future research on this novel implant. There is a need to correctly identify selection criteria for patients, who would benefit the most from the XEN Gel Implant.