Assessment of Outcomes and Anatomical Changes in the Upper Urinary Tract Following Flexible Ureteroscopy With a Flexible and Navigable Suction Ureteral Access Sheath: 3-Month Results From a Multicenter Study.

Objective: To study the long-term outcomes of the flexible and navigable suction ureteral access sheath (FANS) in flexible ureteroscopy (FURS). FANS has well-established efficiency and 30-day perioperative safety; however, its influence on pelvicalyceal and ureteric anatomy remains to be investigated.

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. Thirty-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: Three hundred-ten patients were analyzed. Median age was 51; median stone volume was 1584 mm. 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 14 minutes, median ureteroscopy time was 30 minutes, and median total operation time was 45 minutes. 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%. Thirty-day reintervention rate was 4.2% (13 cases). Three-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.

Conclusion: The extremely low rates of 3-month adverse outcomes, high immediate SFR, and low 30-day reintervention rates further strengthen the evidence for safety and effectiveness of FANS.