New ureteral access sheaths: a double standard.

Objective To investigate the functional characteristics of the traditional and new single-wire ureteral access sheath (UAS) configurations relating to insertion, positioning, tissue injury, and durability. Materials and Methods Four UAS were tested: Navigator HD (11/13F, Boston Scientific), Re-Trace (10/12F, Coloplast), Flexor-Parallel (P), and Flexor-Regular (R; 9.5/11.5F, Cook Medical). UASs were evaluated for sharpness—(1) foil perforation, (2) tissue skiving (advancing sheath/dilator against fixed foil or bologna models); rigidity—(3) tip bending, (4) sheath buckling; (5) lubricity (dynamic friction through bologna), (6) dilator removal force, (7) kinking forces (side wall compressive forces), and (8) radiopacity. New UASs were used for each trial. A motorized sliding stage was used, and continuous force measurements were recorded with a Mark-10 digital force gauge. Results The Navigator HD had the largest external diameter (13.02F). Re-Trace had the longest (51 mm) and most flexible tip (0.942 lb, P P P P P Conclusion The Navigator HD was the most slippery and rigid sheath, whereas the single-wire systems had lower buckling forces and required more force to remove their dilators. Cook sheaths appeared the least traumatic.