Efficacy and safety of bilateral same session flexible ureteroscopy using flexible and navigable suction ureteral access sheath (FANS) versus conventional access sheath: a prospective randomized comparative study

While research on the comparison between the Flexible and Navigable Suction Ureteral Access Sheath (FANS) and the traditional ureteral access sheath (TUAS) in flexible ureteroscopy for unilateral stones is scarce, this study aims to assess their performance during bilateral same-session flexible ureteroscopy, examining safety, efficacy, and perioperative outcomes. In total, 100 cases aged 23 to 65 with bilateral stones under 20 mm were randomized into two groups: one using the NUAS and the other the TUAS. Exclusion criteria encompassed pediatric cases, individuals with untreated coagulopathies, and those with stones in calyceal diverticula. A significant difference was observed in the distribution of stone-free rates (SFRs) between the groups, with the FANS group demonstrating a elevated grade A (absolute stone-free) rate and fewer grade C (2.1 to 4 mm residual stones) as opposed to the TUAS one (70% vs. 20%, and 6% vs. 48%, p < 0.001). Additionally, the operative time was significantly longer in the TUAS group (58.4 ± 14.53 min) as opposed to the FANS group (48.41 ± 13.9 min, p = 0.001). The infection rate was also significantly elevated in the TUAS group (16%) as opposed to the FANS group (4%, p = 0.046). In terms of intraoperative and postoperative adverse events, the groups were similar (p < 0.05). FANS emerges as a promising and safer approach for bilateral flexible ureteroscopy, offering superior SFRs, faster procedure times, and fewer infections when as opposed to the traditional TUAS approach.