Comparative Safety, Effectiveness, and Outcomes of 10/12 Fr Versus 12/14 Fr Ureteral Access Sheaths and the Impact of Suction-Enabled Sheaths in Ureteroscopy.

The choice of ureteral access sheath (UAS) size in flexible ureteroscopy (fURS) is pivotal in balancing endoscopic performance with ureteral safety. Larger sheaths (12/14 Fr) provide superior irrigation flow and intrarenal pressure control but raise concerns regarding ureteral trauma, particularly in unstented ureters. This PRISMA-aligned systematic review (January 2010-August 2025) synthesizes the available evidence comparing 10/12 Fr and 12/14 Fr UAS, both standard and suction-enabled, in terms of pressure modulation, irrigation efficiency, thermal regulation, ureteral injury, stricture formation, and infectious outcomes. Emerging data show that suction-assisted 12/14 Fr sheaths significantly lower rates of postoperative fever and sepsis without increasing ureteral injury when applied judiciously. Pre-stenting remains a key strategy for minimizing insertion-related trauma. The findings highlight an evolving clinical paradigm in UAS selection: shifting from a purely size-based choice to a physiology-driven approach that optimizes safety, visibility, and procedural efficiency.