Recanalization of XEN-45 gel stent occlusion with cortical material after phaco-XEN surgery using Nd: YAG laser treatment

Abstract

Introduction: The XEN Gel Stent (Allergan Inc., CA, USA) has been widely used in minimally invasive glaucoma surgery to lower intraocular pressure considering reasonable efficacy and safety profiles. However, the XEN gel stent could be occluded by fibrin, blood clots, or the iris due to its small lumen design for preventing postoperative hypotony. To date, only a few studies have assessed XEN occlusion after combined phacoemulsification with XEN gel implantation and how to manage this condition. We describe the first case report of XEN gel stent obstruction by cortical material, demonstrated by anterior segment optical coherence tomography (AS-OCT), which resolved effectively after low-energy neodymium-doped yttrium aluminum garnet (Nd: YAG) laser shock wave treatment. Patient Information: A 76-year-old Korean male patient underwent uncomplicated phaco-XEN-gel stent implantation and presented with low intraocular pressure (IOP) with a well-functioning filtering bleb during the first postoperative 4 days. On postoperative day 5, the XEN lumen was occluded by the cortical material, with an intraocular pressure elevation of 28 mm Hg. Slit-lamp examination revealed that cortical material was causing a block into the internal ostium of the XEN gel implant. AS-OCT examination also demonstrated the presence of hyper-reflective materials at the intraluminal portion and peritubular portion around the internal ostium of the XEN gel implant. Diagnosis: XEN gel stent occlusion with cortical material after Phaco-XEN surgery. Interventions: Low-energy Nd: YAG laser shock wave treatment. Outcomes: The IOP dropped from 28 mm Hg to 8 mm Hg immediately after treatment. Transient hypotony and a slightly shallow anterior chamber were noted over the 3 days after YAG laser treatment. The IOP continued to be well-controlled until 3 months later (range; 6 - 12 mm Hg). Conclusions: To the best of our knowledge, this is the first case report on the efficacy of Nd: YAG laser treatment for recanalization of XEN implant occluded by the cortex. Moreover, AS-OCT could provide additional clinical information for recanalization of the XEN gel stent.

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

“…10 In contrast, several possibilities for the management of XEN internal ostium full blockage have been described. [18][19][20][21] The use of Nd:YAG laser treatment is widely recognized as a safe and effective procedure. In this regard, Fellman et al outlined a technique of Nd:Yag laser treatment in the proximity of the intracameral tip portion of the stent to disperse only supposed intraluminal debris.…”

“…According to the literature, the recommendations for the treatment of an early cystic bleb include initially DOC and aqueous suppressants prescription, followed eventually by needling or surgical revision if the conservative approach fails 10 . In contrast, several possibilities for the management of XEN internal ostium full blockage have been described 18–21 . The use of Nd:YAG laser treatment is widely recognized as a safe and effective procedure.…”

“…10 In this context, an early increase in postoperative IOP may be due to the following causes: (i) occlusion of the internal ostium by fibrin, Descemet's membrane and blood clots or iris, (ii) device malposition, or (iii) bleb fibrosis. 7,8,16,17 Several reports have shown various procedures for the management of XEN internal ostium occlusion, including the Nd:YAG laser lysis, 18,19 the removal with Inner Limiting Membrane forceps, 20 and the tube trimming with vitreous scissors. 21 Conversely, corrective measures for the bleb fibrosis process and the outflow restriction have included digital ocular compression (DOC), needling procedure, injection of antifibrotic agents, and open conjunctiva surgical revision.…”

“…Several reports have shown various procedures for the management of XEN internal ostium occlusion, including the Nd:YAG laser lysis, 18,19 the removal with Inner Limiting Membrane forceps, 20 and the tube trimming with vitreous scissors 21 . Conversely, corrective measures for the bleb fibrosis process and the outflow restriction have included digital ocular compression (DOC), needling procedure, injection of antifibrotic agents, and open conjunctiva surgical revision 10,22,23 …”

Single versus Double PreserFlo MicroShunt Implantation in Glaucoma Patients: A Retrospective Cohort Study

“…These intraluminal occlusions cannot be visualized by gonioscopy and arguably are thus an underrecognized problem. According to reports, fluid shockwaves provoked by neodymium-doped yttrium aluminum garnet (Nd:YAG) laser application to the anterior chamber were successful for dislodging the intraluminal debris, restoring stent patency and aqueous humor outflow [26, 27]. We believe it is possible that intraluminal occlusion may resolve spontaneously over time and that outflow through a specific tube may temporarily suspend also due to other factors like local pressure fluctuations and changes in the rheologic conditions within the anterior chamber.…”