Flexible ureteroscopy under local anesthesia for 2-4 cm renal stones: FANS outperforms traditional sheaths.

To evaluate the efficacy and safety of a Flexible and Navigable Suction Ureteral Access Sheath (FANS) in flexible ureteroscopic lithotripsy (FURL) under local anesthesia for renal stones 2-4 cm. We retrospectively analyzed clinical data from patients with renal stones 2-4 cm who underwent local anesthesia FURL from January 2023 to December 2024. Patients were divided into two groups based on the type of sheath used: FANS or traditional ureter access sheath (T-UAS) group. Demographic data and perioperative indicators were compared. A total of 372 patients were included in the study, with 187 in the FANS and 185 in the T-UAS group. FANS achieved an 78.6% one-time stone-free rate (SFR) (vs. 57.8% in T-UAS, P < 0.001), with significantly lower postoperative fever (2.1% vs. 8.1%) and steinstrasse (1.1% vs. 5.9%). FANS enhances FURL efficacy for 2-4 cm renal stones under local anesthesia, provides an alternative to percutaneous nephrolithotomy (PCNL) for select patients.