Flexible Ureteroscopy with a Flexible and Navigable Suction Ureteral Access Sheath Versus Mini-Percutaneous Nephrolithotomy for Treatment of 2-3 cm Renal Stones: An International, Multicenter, Randomized, Noninferiority Trial.

Abstract

The efficacy and safety of flexible ureteroscopy (f-URS) using a flexible and navigable suction ureteral access sheath (FANS) versus mini-percutaneous nephrolithotomy (mPCNL) for 2-3 cm renal stones remain controversial. Our aim was to conduct a study to address the evidence gap. We conducted a multicenter, noninferiority, randomized controlled trial in which 720 patients were enrolled across 12 centers in China, Turkey, Russia, India, and Malaysia from August 2024 to February 2025. Patients with 2-3 cm stones were randomized 1:1 to FANS f-URS or mPCNL. The primary outcome was the immediate stone-free rate (SFR) (noninferiority margin -8%). Secondary outcomes included operative time, hospital stay, auxiliary procedures, 3-mo SFR, complications, and quality of life (QoL) improvement. FANS f-URS was noninferior to mPCNL in terms of the immediate SFR (risk difference [RD] -1.4%, 95% confidence interval [CI] -6.7% to 3.9%; noninferiority 1-sided p = 0.007). FANS f-URS had a longer operative time (mean difference [MD] 29 min, 95% CI 24-33; p < 0.001), lower transfusion rate (RD -2.2%, 95% CI -3.9% to -0.5%; p = 0.021), shorter postoperative hospitalization (MD -2.5 d, 95% CI -2.8 to -2.2; p < 0.001), and a greater improvement in QoL score (MD 4.8, 95% CI 3.0-6.6; p < 0.001). We found no evidence of differences in auxiliary procedures, the 3-mo SFR, or infection-related complications. FANS f-URS had a noninferior SFR in comparison to mPCNL for 2-3 cm renal stones, with lower risk of bleeding risk, shorter hospitalization, and superior QoL. These findings support FANS f-URS as a viable alternative to mPCNL for 2-3 cm stones.