A Novel Thermally Expanding Nickel–Titanium Alloy Metallic Ureteral Stent for the Management of Ureteral Strictures

Abstract

Background:

The management of complex ureteral strictures remains a significant urologic challenge. Although metallic stents offer an alternative to traditional polymer stents, long-term data on their efficacy, particularly for newer devices, are limited. This study evaluates the safety and efficacy of a novel, domestically produced thermally expanding nickel–titanium alloy stent (Fulbright^®) in treating various ureteral strictures.

Methods:

A prospective, single-center study was conducted between August 2024 and September 2025. Consecutive patients with ureteral strictures of diverse etiologies (e.g., stone-related, postradiation, iatrogenic, idiopathic) were enrolled. All participants underwent implantation of the thermally expanding nickel–titanium alloy stent (Fulbright). Primary outcomes included technical success, stent patency, and changes in renal function parameters (serum creatinine, estimated glomerular filtration rate (eGFR), hydronephrosis volume) assessed during follow-up.

Results:

A total of 21 patients (representing 23 ureteral units) were included. The cohort presented with complex strictures of varied etiology: urolithiasis (39.1%, n = 9), radiation-induced (21.7%, n = 5), iatrogenic (17.4%, n = 4), idiopathic (13.0%, n = 3), and tumor extrinsic compression (8.7%, n = 2). The primary endpoint of an effective decompression was achieved in 87.0% of cases over a median follow-up of 5.0 months (interquartile range [IQR] 2.0–6.0). Postoperative renal function improved significantly, with serum creatinine levels decreasing from a median of 95.0 μmol/L (IQR 73.0–126.0) to 84.0 μmol/L (IQR 68.0–115.0) (p < 0.001). Concurrently, the eGFR increased significantly from 64.8 ± 23.3 mL/min/1.73 m² to 73.1 ± 22.1 mL/min/w1.73 m² (p = 0.001). A marked reduction in hydronephrosis volume was also observed, from a median of 57.9 cm³ (IQR 27.7–109.8) to 12.9 cm³ (IQR 5.7–38.4) (p < 0.001). Stent migration was the predominant complication, occurring in 17.4% (4/23) of cases, one of which was effectively managed endoscopically.

Conclusions:

The novel thermally expanding nickel–titanium alloy stent (Fulbright) represents a promising, safe, and effective minimally invasive therapeutic option for managing both benign and malignant ureteral strictures.