Flexible ureteroscopy with a flexible and navigable suction ureteral access sheath versus mini-percutaneous nephrolithotomy for 1–2 cm lower pole renal stones: Protocol for an international, multicentre, randomized non-inferiority trial (FLAME trial)

Zhu W., Zhong J., Wang K., Yin G., Leung C., Gadzhiev N., ...Daha Fazla

BJUI Compass, cilt.6, sa.12, 2025 (ESCI, Scopus) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 6 Sayı: 12
  • Basım Tarihi: 2025
  • Doi Numarası: 10.1002/bco2.70114
  • Dergi Adı: BJUI Compass
  • Derginin Tarandığı İndeksler: Emerging Sources Citation Index (ESCI), Scopus
  • Anahtar Kelimeler: FANS, flexible and navigable suction ureteral access sheath, flexible ureteroscopy, lower pole, PCNL, renal stones
  • Ankara Üniversitesi Adresli: Evet

Özet

Background: Lower pole renal stones measuring 1–2 cm remain challenging to treat. While mini-percutaneous nephrolithotomy (mini-PCNL) provides high stone-free rates (SFRs), it carries tract-related morbidity. Flexible ureteroscopy (f-URS) is less invasive but limited in SFR. The flexible and navigable suction ureteral access sheath (FANS) has shown promise in improving stone evacuation and intrarenal pressure control. We hypothesize that FANS f-URS is non-inferior to mini-PCNL for patients with 1–2 cm lower pole stones in SFR. Study Design: The FLAME trial is an international, multicentre, randomized, non-inferiority study directly comparing FANS-f-URS with mini-PCNL in this setting. Endpoints: The primary outcome is immediate SFR within 72 hours on low-dose CT. Secondary outcomes include SFR at 1 month, operative time, postoperative pain, hospital stay, complications (Clavien–Dindo) and quality-of-life changes. Patients and Methods: A total of 640 adults with CT-confirmed 1–2 cm lower pole renal stones will be randomized 1:1 to undergo FANS-f-URS or mini-PCNL across 20 high-volume urology centres worldwide. Randomization is centralized and stratified by site. Radiologists and statisticians will remain blinded to allocation. Sample size was calculated assuming an 85% SFR for both arms, an 8.5% non-inferiority margin, 80% power and 15% attrition. Analyses will follow both intention-to-treat and per-protocol principles. Trial registration: ClinicalTrials.gov NCT07159035.