Optimal deflection techniques for flexible and navigable suction ureteral access sheaths (FANS): a comparative in vitro PEARLS analysis

Purpose Flexible and navigable suction ureteral access sheaths (FANS) have been introduced without current evidence on how to optimize deflection. Aim was to evaluate in vitro deflection angles with 2 different FANS techniques–sheath advancement and ureteroscope deflection; and effects of sheath size-ureteroscope combinations. Methods We evaluated in vitro deflection angles of 10/12Fr, 11/13Fr and 12/14Fr FANS (Hunan Reborn Medical Co. Ltd) with six single-use flexible ureteroscopes (Pusen Uscope 7.5Fr, OTU WiScope 7.5Fr, OTU WiScope 8.6Fr, Innovex EU-scope 8.7Fr, Red Pine RP-U-C12 8.7Fr and Boston Scientific Lithovue 9.5Fr). Two deflection techniques were tested: (1) sheath advancement—advancing the sheath forward over a maximally deflected ureteroscope, and (2) ureteroscope deflection—maximally deflecting the ureteroscope from various starting positions relative to tip of the sheath. Results Intra and inter-scope comparisons of maximum deflection angles were significantly different (all ANOVA p