A Silicone-Covered Self-Expanding Metal Stent with Anti-migration Features for Treating Malignant Ureteral Obstruction

Purpose To evaluate the effectiveness and safety of the Urexel stent for treating malignant ureteral obstruction (MUO). Materials and Methods This retrospective study included 129 patients (mean age: 57.9 +/- 11.8 years; men: n = 64, 49.6%; ureteral units [UUs]: N = 175) who underwent Urexel stent placement to treat MUO between March 2013 and April 2021. The Urexel stent is a fully covered self-expanding metal stent. To reduce stent migration, the proximal end of the stent has an additional layer of stent mesh and is flared mildly. Results Eighty-three patients (64.3%) had unilateral MUO (right side: n = 47, 36.4%; left side: n = 36, 27.9%), and 46 patients (35.7%) had bilateral MUO. Successful Urexel stent placement after successful guidewire passage of the obstructed ureteral segment was achieved in 172 UUs, rendering a technical success rate of 98.3%. Stent malfunction occurred in 37 UUs (21.4%) during follow-up, including tumor overgrowth (n = 29), tumor ingrowth (n = 3), stent migration (n = 3), and stent collapse (n = 2). A total of 120 patients (93.0%) died during a median follow-up of 4.1 months (range: 0.2 - 33.5). The median survival of the patients was 4.4 months (interquartile range [IQR] 2.0 - 8.8). The median malfunction-free survival of the patients was 3.6 months (IQR: 1.6 - 7.9). Fifteen grade 3 or higher complications occurred in 14 patients (10.9%), including flank pain (n = 10), gross hematuria (n = 4), and dysuria (n = 1). Conclusion Urexel stent placement may be effective and safe for treating MUO.