Combining the power of flexible and navigable suction access sheath (FANS) and direct in scope suction (DISS): introduction to the flexible integrated retrograde suction-ureteroscopy technique (FIRST) procedure-an audit study by the endourology section of the European Association of Urology.

OBJECTIVE

Flexible ureteroscopy (F-URS) with suction technology has become a minimally invasive surgery for the management of renal stones. While the Flexible and Navigable Suction Ureteral Access Sheath (FANS) and Direct In-Scope Suction (DISS) ureteroscopes individually have proven benefits and restrictions, there is no dedicated research if integrating both these technologies can complement the limitations of each to improve suction F-URS outcomes. This audit introduces the Flexible Integrated Retrograde Suction-Ureteroscopy Technique (FIRST) procedure, which integrates FANS with a DISS ureteroscope, and compares its outcomes against DISS combined with a conventional ureteral access sheath (C-UAS).

METHODS

This prospective audit enrolled 64 adult patients undergoing F-URS with a DISS ureteroscope between August 2024 and October 2025 at 2 institutions. Patients were allocated to DISS with FANS (Group 1, n = 37) or DISS with C-UAS (Group 2, n = 27) based on surgeon discretion and device availability. The primary outcome was 30-day stone-free rate (SFR) assessed by non-contrast CT scan (single fragment up to 2 mm). Secondary outcomes included perioperative complications, renal function, and 3-month residual fragment rate, and the surgeon-reported ergonomics of procedures.

RESULTS

Despite significantly greater stone burden in Group 1, the FIRST procedure achieved a superior 30-day SFR of 83.8% versus 70.4% in Group 2, with zero-residual-fragment status in 72.9% versus 48.1% of patients, respectively (p < 0.001). At three months, zero residual fragments were detected in all patients in Group 1 compared to 22.2% in Group 2 (p < 0.01), translating into zero reinterventions in Group 1. Surgeon-reported ergonomics, intraoperative visibility, and simultaneous DISS-laser manipulation were rated significantly superior in Group 1. Overall 30-day complication rates were comparable between groups (18.9% vs. 22.2%), with no high-grade (Clavien ≥ 3) complications and preserved renal function in either cohort.

CONCLUSIONS

The FIRST procedure using this integrated suction technique can potentially give 100% SFR with significantly improved ergonomics with negligible complications. These findings support further investigation of the integrated FIRST procedure in routine and anatomically complex renal stone disease.