METHODS: This was a prospective study of patients with normal renal anatomy who underwent FURS with FANS for renal stones from April 2023 to August 2024 in 16 centers worldwide. 30-day postoperative stone free rate and delayed complications after 3 months were analyzed with a non-contrast CT scan and contrasted CT urogram respectively. The primary aim was to report if FANS could potentially cause pelviureteric junction, pelvicalyceal or ureteric complications.

RESULTS: 310 patients were analyzed. Median age was 51; median stone volume was 1584 mm3. Disposable scopes were used in 58.1%. Predominant laser energies were Thulium fiber laser (56.1%) followed by Thulium-YAG laser (20.6%). Median laser time was 14min, median ureteroscopy time was 30min, and median total operation time was 45min. Ureteric injury occurred in 11 patients (3.5%), of which 10 were Traxer-Thomas Grade 1. On 30-day NCCT, 63.5% of patients had zero residual fragments; overall stone-free status was seen in 95.1%. 30-day reintervention rate was 4.2% (13 cases). 3-month CT urogram showed ureteric stenosis in only 1 patient (0.3%) who was managed by dilatation and stenting. No other anatomical anomalies were recorded.