The allium stent for the complex ureteral stricture-deeper experience of a series case review.

Background: Allium stents are widely used in patients with ureteral stricture, with ongoing research continuously evaluating their clinical safety and efficacy. Objective: This study aimed to describe our technique and report the outcomes of Allium stent in the treatment of refractory ureteral strictures. Design setting and participants: We retrospectively collected perioperative data on all patients treated with Allium stents in our department between January 2017 and April 2024 and assessed their clinical outcomes. Surgical procedure: Following ureteroscopy, a guidewire was advanced under fluoroscopic guidance into the renal pelvis. The retrograde ureterography was performed to determine the location and length of the ureteral stricture. Dilation was performed using a ureteral balloon dilator, a flexible ureteroscope sheath, or a rigid ureteroscope. Subsequently, the Allium stent was deployed into the stricture segment and confirmed via fluoroscopic imaging. Results: A total of 23 patients (25 ureters) were included, with a mean age of 57.7 years (32-76 years). The mean length of ureteral strictures was 4.5 cm (range: 1-18 cm). All stents were successfully positioned. As of December 2024, the stent patency rate was 68%, with a median follow-up of 39.5 months (13-67 months). In eight patency failure cases, the mean indwelling time was 14 months, with the shortest recorded duration being 2 months. Causes of failure included four (50%) stent migration, one (12.5%) encrustation, two (25%) persistent stenosis and severe infection (12.5%). Management strategies for these cases included two (25%) stent removal, two (25%) robot-assisted pyeloureteroplasty, one (12.5%) ureterolithotripsy, one (12.5%) exchange with a new Allium stent, one (12.5%) add new Allium stent, and one (12.5%) replacement with a different type of metal stent. Notably, one case of a ruptured ureter was successfully bridged with an Allium stent, and another case of a uretero-vaginal fistula was effectively treated with Allium stent, both without complications. Conclusions: Allium stents appear to be a feasible and effective treatment for various ureteral strictures, including cases of ureteral perforation and rupture. However, long-term complications such as stent migration and occlusion remain challenges that should not be overlooked.