Impact of positioning of ureteral access sheath in patients undergoing flexible ureteroscopy for renal stone treatment: a retrospective observational study

Background: Flexible ureteroscopy (fURS) has become a first-line therapeutic approach for renal calculi ≤2 cm in diameter. The use of ureteral access sheaths (UASs) has significantly enhanced the efficacy of fURS procedures; however, the optimal positioning of UAS within the ureter remains a topic of ongoing debate. This study aims to evaluate the impact of UAS positioning—classified as either juxta-pelvic or intra-ureteral—on perioperative and postoperative outcomes. Methods: A retrospective cohort analysis was conducted at the University of Campania “Luigi Vanvitelli” (Naples, Italy) between June 2022 and June 2024, including patients who underwent fURS for the management of renal stones. Demographic data, stone characteristics, intraoperative parameters, and postoperative outcomes were systematically collected and analysed. Primary endpoints included 30-day stone-free rates (SFRs), while secondary endpoints encompassed operative duration, complication rates, and length of hospital stay. Statistical comparisons were performed to assess differences between the two UAS positioning groups. Results: The study cohort comprised 64 patients. Comparative analysis revealed no statistically significant difference in 30-day SFR between the juxta-pelvic and intra-ureteral UAS positioning groups (P=0.86). Additionally, UAS placement did not significantly influence operative time (P=0.74) or hospitalization duration (P=0.45). No notable differences were observed in intraoperative (P=0.75) or postoperative complication rates (P=0.87) based on UAS positioning. The 30-day SFR was 83.8% in the juxta-pelvic group and 85.2% in the intra-ureteral group [risk difference =−1.4%; 95% confidence interval (CI): −15.2 to 12.4; P=0.86]. Operative time and hospitalization were also comparable (median: 75 vs. 74 min, Cohen’s d=0.07; 95% CI: −0.33 to 0.47; P=0.74). Conclusions: These findings suggest that the anatomical placement of UAS—whether juxta-pelvic or intra-ureteral—does not substantially alter surgical outcomes in fURS. Both approaches demonstrate comparable efficacy in achieving optimal stone clearance and perioperative safety. Further prospective studies are warranted to explore potential long-term implications and refine UAS positioning strategies.