[Long-term efficacy evaluation of coated metal stent implantation for ureteroscopic lithotripsy related refractory ureteral stricture].

Objective: To comprehensively evaluate the long-term efficacy and safety of coated metal stent implantation for ureteroscopic lithotripsy related refractory ureteral stricture (URL-rUS).

Methods: Electronic medical records of 30 patients (31 affected renal units) receiving coated metal stent implantation for URL-rUS from Sept. 2018 to Aug. 2021 at Peking University People' s Hospital were reviewed for analysis. Coated metal stents were implanted in retrograde approach via ureteroscope. Last outpatient follow-up was set as endpoint. Baseline information, stricture characteristics and decompression strategy before coated metal stent implantation were retrospectively collected. Serum creatinine (Scr) concentration and renal pelvis width (RPW) were used as renal function indicators. Peri-operative and long-term complications and according outcomes were recorded. For the patients who had double J tubes implanted for drainage before operation, Ureteral Stent Symptom Questionnaire (USSQ) was applied to evaluate the stent-related discomforts and quality of life (QoL) before and after surgery. Data analysis was conducted with SPSS (version 25.0; SPSS, Chicago, IL, USA).

Results: Totally 30 patients with 31 affected renal units were included. All the patients previously underwent unsuccessful traditional endoscopic balloon dilation or endoureterotomy before receiving coated metal stent implantation. The mean age was (45.5±9.3) years old. The median follow-up time were 14 (6-36) months. All coated metal stents were successfully placed with a median duration of 60 (30-195) min. No severe peri-operative complications occurred. At endpoint, 28 (90.3%) sides of coated metal stents remained unobstructed with a longest indwelling time of 36 months. Causes of failures included stent migration (1 case, 3.2%), encrustation (1 case, 3.2%) and repeated stent related urinary tract infection (1 case, 3.2%). When compared with the baseline, significant reductions were observed in both Scr concentration and RPW at endpoint [(90.7±19.5) mmol/L (83.1±18.5) μmol/L, < 0.01, for Scr; (2.5±1.3) cm (1.9±0.8) cm, < 0.01, for RPW], indicating good preservation of renal function and remission of hydronephrosis. For 26 patients with double J stents before operation, significant reduction of USSQ average score (100.4±6.6 82.1±4.9, < 0.01) evidenced better life quality preserving ability of coated metal stent versus double J stent.

Conclusion: Coated metal stent implantation is a safe and minimally invasive management of ureteral stricture providing a satisfying long-term patency rate, after which the patients' quality of life and renal function could be both improved. This method could serve as a promising alternative long-term maintenance treatment option for patients with URL-US, especially when traditional endoscopic interventions failed.