Assessment of anatomical outcomes in the upper urinary tract following flexible ureteroscopy with flexible and navigable suction ureteral access sheath: 1‐year results from a multicentre study

Introduction: Flexible and navigable suction access sheath (FANS) with flexible ureterorenoscopy (FURS) has demonstrated favourable 30-day and 3-month outcomes for renal stones in normal anatomy. We aimed to investigate the long-term 1-year safety and efficacy of FANS for renal and ureteric stones in normal or anomalous anatomy. Methods: This prospective multicentre study included adults undergoing FURS with FANS across 11 centres in 9 countries (April 2023 to August 2024), with follow-up until August 2025. Anatomical outcomes were assessed by contrast CT (or ultrasound if CT not available) at 1 year; stone-free rate (SFR) was assessed via noncontrast CT at 30 days. The primary aim was to report if altered anatomy, such as pelvicalyceal or pelviureteric or ureteric stricture, occurs at a later stage. Results: ; median Hounsfield unit was 1100. Most procedures (84%) used a 7.5Fr scope with 10/12 Fr FANS. Regarding exit strategies, 65% were stented, 14% had an overnight ureteric catheter and 21% were tubeless. Mild bleeding occurred in 17% with no postoperative sepsis, transfusions or persistent hematuria. One patient (0.35%) experienced a Grade 1 ureteric injury. On a 30-day CT, 82% achieved zero residual fragments (Grade A SFR). On 1-year CT, five patients (1.7%) were diagnosed with ureteric stricture, 9.7% had persistent residual fragments, and 5.6% developed new ipsilateral stones. Of the five patients with strictures, three had a history of ureteric re-implantation and only one had been prestented. Serum creatinine showed no significant change from baseline. Conclusions: This study reports the longest 1-year follow-up data for patients undergoing FURS with FANS to date. The study did not identify a high rate of late anatomical complications after successful FANS deployment in the treatment of renal and ureteric stones. Caution is warranted in patients with a history of ureteral re-implantation due to elevated risk of stricture formation.