Steffi Kar Kei Yuen, Chi-Fai Ng, Khi Yung Fong, Bhaskar Kumar Somani, Boyke Soebhali, Mohamed Elshazly, Vigen Malkhasyan, Karl Tan, Luis Rico, Mehmet Ilker Gokce, Han Jie Lee, Nariman Gadzhiev, Tzevat Tefik, Jianwei Cao, Albert El Hajj, Chi-Ho Leung, Jeremy Yuen Chun Teoh, O. Traxer, Ben Hall Chew, Daniele Castellani, Vineet Gauhar
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.