Flexible ureteroscopy with a navigable suction sheath versus mini‑PCNL for 1–2 cm lower‑pole kidney stones
Flexible Ureteroscopy With a Flexible and Navigable Suction Ureteral Access Sheath Versus Mini-Percutaneous Nephrolithotomy for 1-2 cm Lower Pole Renal Stones: an International, Multicenter, Randomized Non-Inferiority Trial (FLAME Trial)
This trial will try whether flexible ureteroscopy using a navigable suction ureteral access sheath (FANS) works as well as mini‑PCNL to remove 1–2 cm lower‑pole kidney stones in adults.
Quick facts
| Phase | Not applicable |
|---|---|
| Study type | Interventional |
| Enrollment | 640 (estimated) |
| Ages | 18 Years to 75 Years |
| Sex | All |
| Sponsor | The First Affiliated Hospital of Guangzhou Medical University Academic / other |
| Locations | 1 site (Guangzhou, Guangdong) |
| Trial ID | NCT07159035 on ClinicalTrials.gov |
What this trial studies
The FLAME trial is an international, multicenter, randomized, non‑inferiority study enrolling 640 adults across 20 high‑volume urology centers in China, Russia, Turkey, and India to compare FANS‑assisted flexible ureteroscopy with mini‑percutaneous nephrolithotomy for 1–2 cm lower‑pole renal stones. Participants are randomized 1:1 to either FANS‑assisted flexible ureteroscopy or mini‑PCNL with standardized perioperative care and imaging. The primary endpoint is immediate stone‑free rate on non‑contrast CT within 72 hours after surgery, and secondary endpoints include 1‑month SFR, operative time, pain scores, length of hospital stay, complications (Clavien‑Dindo), renal function changes, and health‑related quality of life. The FANS device is designed to improve irrigation control, actively suction fragments, and reduce intrarenal pressure, and the trial will determine whether these features translate into comparable or better clinical outcomes than mini‑PCNL.
Who should consider this trial
Good fit: Adults aged 18–75 years with one or multiple lower‑pole kidney stones measuring 1–2 cm on CT, ASA class 1–3, and able to give informed consent are eligible.
Not a fit: Patients with significant urinary tract anatomical anomalies, stones in a calyceal diverticulum, prior open renal surgery, uncorrectable coagulopathy, active uncontrolled UTI, severe cardiopulmonary disease, pregnancy, or inability to tolerate positioning are unlikely to benefit or be eligible.
Why it matters
Potential benefit: If successful, FANS‑assisted flexible ureteroscopy could offer a less invasive option with similar stone clearance while reducing pain, hospital stay, and intrarenal pressure‑related risks.
How similar studies have performed: Both flexible ureteroscopy and mini‑PCNL are established, effective treatments for renal stones, but the specific FANS suction sheath is relatively new and has limited comparative data against mini‑PCNL.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: 1. Adults aged 18-75 years; 2. American Society of Anesthesiology (ASA) score 1-3; 3. Lower pole renal stones-single or multiple-with a maximal diameter of 1-2 cm confirmed by CT; 4. Ability to provide written informed consent and adhere to trial requirements. Exclusion Criteria: 1. Significant urinary tract anatomical anomalies (e.g. horseshoe kidney, ileal conduit); 2. Stones located within a calyceal diverticulum; 3. History of open nephrolithotomy or ureterolithomy (due to resultant intrarenal anatomical distortion); 4. Absolute contraindications to either FANS-f-URS or mini-PCNL, including: * Uncorrectable coagulopathy; * Active, uncontrolled urinary tract infection; * Severe cardiopulmonary disease precluding safe general anesthesia (e.g. decompensated heart failure, refractory COPD); * Pregnancy; * Inability to tolerate lithotomy or prone positioning; 5. Inability to understand or complete trial documentation.
Where this trial is running
Guangzhou, Guangdong
- The First Affiliated Hospital of Guangzhou Medical University — Guangzhou, Guangdong, China (Recruiting)
Study contacts
- Study coordinator: Wei Zhu, Ph.D.
- Email: doczw1989@126.com
- Phone: +8613622754991
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.