[Efficacy of thermo-expandable nickel-titanium alloy ureteral stent placement as maintenance therapy for ureteral strictures].

Abstract

Objective: To evaluate the clinical efficacy and safety of thermo-expandable nickel-titanium alloy ureteral stents (Memokath-051) for maintenance therapy of ureteral strictures.

Methods: A retrospective analysis was conducted on the clinical data of 16 patients with ureteral strictures admitted to Beijing Geriatric Hospital from January 2024 to April 2025. The cohort comprised 3 males and 13 females, with a mean age of (57.60±9.79) years. Etiologies included post-radiation stricture following abdominopelvic tumor radiotherapy in 13 patients, retroperitoneal fibrosis in 2, and ureteral granuloma in 1. All the 16 patients had experienced failure of previous indwelling double-J stent placement and subsequently underwent conversion to thermo-expandable nickel-titanium alloy ureteral stent insertion. Among the 16 patients, 7 had bilateral ureteral lesions, with a total of 23 ureteral units treated. Operative time, complications (graded according to the Clavien-Dindo classification), stent patency rate, and ureteral stent symptom questionnaire (USSQ) scores were recorded. Follow-up assessments of serum creatinine levels and hydronephrosis improvement were performed 3, 6, and 12 months postoperatively.

Results: All 23 stents were successfully placed in the 16 patients (technical success rate, 100%), with a mean operative time of (51.52±9.55) min. The overall stent patency rate 12 months postoperatively was 82.61% (19/23). Early complications occurred in 7 patients. Long-term complications developed in 4 patients, including stent migration (n=1), tissue hyperplasia-induced obstruction (n=2), and stone-related obstruction (n=1); the remaining 5 patients had no complications. Three months postoperatively, serum creatinine decreased from the preoperative baseline of 186.80 (111.80, 244.93) μmol/L to 103.05 (96.20, 135.97) μmol/L (P < 0.01), and hydronephrosis width decreased from 3.20 (2.78, 3.40) cm to 2.05 (1.08, 2.20) cm (P < 0.01). Serum creatinine levels and hydronephrosis remained stable 6 and 12 months postoperatively. Compared with the previous indwelling period of double-J stents, USSQ scores showed significant improvements in urinary symptoms (34.75±2.34 vs. 23.75±3.26), bodily pain (6.50±2.26 vs. 3.00±1.22), general health status, and work performance (all P < 0.001).

Conclusion: Placement of thermo-expandable nickel-titanium alloy ureteral stents (Memokath-051) as maintenance therapy for ureteral strictures is safe and effective. Compared with double-J stenting, it improves renal function and hydronephrosis, and enhances patient quality of life. This approach is particularly applicable to patients with long-segment ureteral strictures secondary to post-radiation etiologies.