Flexible and Navigable Suction Ureteral Access Sheath (FANS) versus conventional stone-pushing technique for impacted upper ureteral stones: a retrospective cohort study

Abstract Background Impacted upper ureteral stones pose a significant risk of ureteral injury and stricture formation during ureteroscopic procedures. The Flexible and Navigable Suction Ureteral Access Sheath (FANS) integrates in-situ lithotripsy, continuous suction, and irrigation. This study aimed to compare the efficacy and safety of FANS with the conventional ureteroscopic technique in the management of impacted upper ureteral stones. Methods A single-center, retrospective cohort study was conducted involving 115 patients (FANS group: n = 50; Conventional group: n = 65). The FANS group underwent in-situ holmium laser lithotripsy with real-time irrigation and suction facilitated by FANS. The Conventional group underwent in-situ lithotripsy using a semi-rigid ureteroscope, with subsequent attempts to push stones into the renal pelvis before flexible ureteroscopic fragment extraction. The rates of ureteral stricture (within 3 months) and other perioperative parameters, including operative time, in-situ lithotripsy duration, and complications, were compared. Results Baseline characteristics were comparable between the two groups. The FANS group exhibited significantly longer operative and in-situ lithotripsy times. However, the incidence of ureteral stricture and perforation was lower in the FANS group (2% vs. 7.7% and 2% vs. 6.2%, respectively). Subgroup analyses revealed that prolonged in-situ lithotripsy time was a significant risk factor for ureteral stricture in the control group but not in the FANS group. The immediate stone-free rate was comparable between groups, with a lower rate of postoperative fever in the FANS group. Conclusion For impacted upper ureteral stones, FANS assisted in-situ lithotripsy significantly reduces the risk of postoperative ureteral stricture without compromising stone clearance, offering a safer alternative to the conventional stone-pushing technique.