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

Author: Gan L, Wang L, Chen J, Tang L.

Geographical coverage: Not reported

Sector: Glaucoma treatment

Sub-sector: XEN gel stent implantation

Equity focus: Not reported

Study population: Adult patients with glaucoma

Review type: Effectiveness review

Quantitative synthesis method: Narrative synthesis

Qualitative synthesis method: Not applicable

Background:

Glaucoma is the leading cause of irreversible blindness, with an estimated 111.8 million people aged 40–80 affected by 2040. Elevated intraocular pressure (intraocular pressure (IOP)) is the only confirmed modifiable risk factor, controlled through medications, laser therapy, and surgery. Trabeculectomy effectively reduces IOP but risks infections, malignant glaucoma, and choroidal haemorrhage. Minimally invasive glaucoma surgery (minimally invasive glaucoma surgery (MIGS)), such as the XEN® gel stent (XEN) gel stent, offers safer alternatives with less recovery time and fewer complications. However, issues like stent occlusion, migration, hypotony, and endophthalmitis remain. Clinical studies highlight these complications, indicating a need for further understanding.

Objectives:

To summarise the complications and their management associated with XEN gel stent implantation.

Main findings:

The review examined 48 studies from 2017 to 2024, covering up to five years of follow-up. The studies included 16 original clinical studies, 28 case reports, and 4 case series. Early postoperative complications ranged from hypotony maculopathy (1.9% to 4.6%) to malignant glaucoma (2.2%). Mid-postoperative issues included XEN stent migration (1.5%) and hypertrophic bleb (8.8%). Late complications were rare, such as spontaneous dislocation. While XEN gel stent implantation offers benefits like reduced tissue damage and shorter surgery times, it poses risks of severe complications. Therefore, close postoperative monitoring is crucial.

Methodology:

The search covered PubMed, EMBASE, Cochrane Library, and China National Knowledge Infrastructure up to February 1, 2024. Studies published in English or Chinese on XEN45 gel stent implantation surgery reporting postoperative complications were included. Two reviewers independently searched for relevant publications and screened reference lists. The review did not specify the number of reviewers for eligibility criteria screening or risk of bias assessment. Data extraction was done independently by two reviewers, and findings were synthesised narratively.

Applicability/external validity:

The review did not explicitly discuss the applicability or external validity of its findings. Nonetheless, it indirectly addressed these aspects by noting the variability in complications associated with XEN45 gel stent implantation across different studies. The review encompassed studies involving diverse patient populations and follow-up durations, recognizing that factors such as surgical techniques, postoperative care, and patient demographics could affect outcomes. While the review provided an extensive summary of complications, its findings may not be universally generalisable across all clinical settings, especially in resource-limited environments or regions with differing healthcare practices.

Geographic focus:

Geographic location of included studies was not reported by the authors.

Summary of quality assessment:

Overall, we have low confidence in the review’s conclusions because of important methodological limitations: the search was restricted to English‑ and Chinese‑language records, the review did not report how many reviewers performed screening or risk‑of‑bias assessment, no critical appraisal of included studies was provided, and a list of excluded records was not supplied. These omissions increase the risk of missed studies and bias in the synthesis.