Safety and efficacy of using traditional ureteral access sheath versus flexible and navigable suction sheath in retrograde intra-renal stone surgery for renal stones ≤ 20 mm: A randomized controlled study

Objectives To evaluate the safety and efficacy of the Flexible and Navigable Suction Sheath (FANS) in comparison with the traditional ureteral access sheath (T-UAS) during retrograde intrarenal surgery (RIRS) for cases with a single renal stone ≤ 20 mm.Methods A total of 140 cases presenting with single renal stones ≤ 20 mm were randomized in a 1:1 ratio to receive either treatment in FANS group or T-UAS group. The primary endpoint was clinically acceptable stone-free status, defined as residual fragments ≤ 4 mm on 1-month non-contrast computed tomography. True stone-free status, defined as no residual fragments, was analyzed as a secondary endpoint, together with operative time and postoperative complications.Results Baseline characteristics and mean stone size were comparable between both groups (14.8 ± 3.0 in FANS vs. 15.40 ± 3.20 in traditional group). Clinically acceptable stone-free status at 1 month did not substantially differ between FANS and T-UAS groups (82.9% vs. 77.1%; p = 0.398). True stone-free status was also comparable between groups (77.1% vs. 71.4%; p = 0.742). Operative time was comparable between groups (52 ± 7 in FANS group vs. 54 ± 12 min in T-UAS group; p = 0.102). Postoperative complications were comparable between FANS and T-UAS groups (11.4% vs. 14.3%; p = 0.614). Although FANS demonstrated a numerically higher SFR and fewer secondary procedures, these variations were not statistically significant.Conclusions In patients undergoing RIRS for single renal stones ≤ 20 mm, FANS did not demonstrate superiority over T-UAS in terms of stone-free rate, operative time, or complication rates. While FANS remains a safe and feasible technique, its incremental clinical benefit in low stone burden appears limited.