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Surgical management of glaucoma patients still represent an open issue for ophthalmologists. The introduction of minimally invasive bleb surgery such as XEN® gel stent has provided alternatives to traditional trabeculectomy. Busch et al. reported four-year results of XEN® 45 gel stent implantation in a Swedish population. This retrospective observational study included all patients who were offered the XEN® 45 gel stent between December 1, 2015, and May 31, 2017. Initially, 139 patients were enrolled, and 103 successfully completed the four-year follow-up. Most cases were primary open-angle glaucoma (POAG) (46.6%), followed by pseudoexfoliative glaucoma (PEXG) (39.8%), and other types of glaucoma (13.6%), including previous angle closure glaucoma and secondary glaucoma. Based on the authors' suggestions, the indications for XEN and trabeculectomy appear essentially identical.
At the time of surgery, the average duration of glaucoma was 9.2 years. After surgery intraocular pressure (IOP) lowered from 24.0 to 16.0 mmHg (−33.3%), 15.1 mmHg (−37.1%), 15.1 mmHg (−37.1%) and 15.9 mmHg (−33.8%) at one, two, three and four years (p < 0.001), respectively. The number of glaucoma medications reduced from 3.5 to 1.5 (p < 0.001). The overall success rate, based on the study's individual target pressures after four years, was 43.7%. Consequently, the failure rate amounted to 56.3%, with secondary glaucoma surgery performed in 43.7% of cases. No differences were observed between the combined and stand-alone procedures, nor between PEXG and POAG, even considering that the Scandinavian population included a greater number of PEXG cases.
The results of this study appeared to accurately reflect and represent the typical population of a glaucoma referral center. This population was characterized by patients with elevated IOP, a broader range of medications, and a longer duration of the disease, including those who had undergone previous glaucoma surgery.
Worse outcomes were observed in cases involving less experienced surgeons and were linked to stent misplacement. This finding underscores the recommendation to perform XEN stent surgery in specialized glaucoma centers with high case volumes. Additionally, patients should be informed about the potential for needling, the need for additional medications, or the possibility of further glaucoma surgery to achieve the target pressure.
One of the main limitations of this study, in addition to its retrospective nature, is the absence of a defined success criterion before surgeryOne of the main limitations of this study, in addition to its retrospective nature, is the absence of a defined success criterion before surgery. Consequently, this could lead to varying interpretations of the outcomes and the management of the patient's medication. The authors didn't provide visual field data at baseline and during follow-up; therefore, our knowledge of glaucoma progression is limited due to the available information.
In conclusion, we can assert that the implantation of the XEN® gel stent is a quite effective surgical procedure with the potential to substantially lower IOP. Recently published evidence supports this conclusion, with data available up to five years post-surgery.1,2