Tolerability of 4.7Fr versus 6Fr ureteral stents following intracorporeal lithotripsy: a single center, patient- and assessor-blinded randomized controlled trial.

OBJECTIVES: Ureteral stents are routinely placed following intracorporeal lithotripsy but are frequently associated with significant morbidity. We aimed to evaluate the tolerability of 4.7Fr versus 6Fr stents in a single center, patient- and assessor-blinded randomized controlled trial. MATERIALS AND METHODS: Of 132 eligible patients, 124 undergoing elective ureterorenoscopy for urolithiasis were randomized 1:1 to receive a 6Fr (n = 63) or 4.7Fr (n = 61) PTFE double-J stent, left in situ for 3 weeks. Accounting for loss to follow-up, 119 participants (4.7Fr, n = 57; 6Fr, n = 62) were analyzed. The primary endpoint was postoperative ureteral stent tolerability, assessed using the International Prostate Symptom Score (IPSS) and Ureteral Stent Symptom Questionnaire (USSQ), while complications were graded using the Modified Clavien-Dindo Classification. RESULTS: Both groups had comparable baseline demographics and similar stone-free rates. At 3 weeks, overall mean IPSS scores were comparable (MD = - 0.7, 95% CI: - 2 to 1, p = 0.356). However, the 4.7Fr group reported significantly better overall USSQ scores than the 6Fr group (73 ± 16 vs. 80 ± 17; MD = - 7, 95% CI: - 13 to - 1.5, p = 0.014). Overall, 84% of patients were complication-free. Grade 3 complications (e.g., stent dislodgment) were more frequent in the 4.7Fr group (8.8% vs. 3.2%; RR = 2.6, 95% CI: 0.5 to 13, p = 0.232). CONCLUSIONS: Smaller 4.7Fr stents significantly reduce urinary symptoms and improve general health compared to standard 6Fr stents, albeit with a slightly elevated risk of early stent dislodgment. TRIAL REGISTRATION: ClinicalTrials.gov identifier: CTRI/2022/09/045724.