NCT07159035

Flexible Ureteroscopy With a Flexible and Navigable Suction Ureteral Access Sheath Versus Mini-Percutaneous Nephrolithotomy 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)

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 640 (estimated)
• Sponsor: The First Affiliated Hospital of Guangzhou Medical University · Academic / Other
• Sex: All
• Age: 18 Years – 75 Years
• Healthy volunteers: Not accepted

Summary

This study, known as the FLAME Trial (Flexible ureteroscopy for Lower pole stones And Mini-pErcutaneous nephrolithotomy), is an international, multicenter, randomized, non-inferiority trial. It aims to compare the effectiveness and safety of flexible ureteroscopy using a flexible and navigable suction ureteral access sheath (FANS) versus mini-percutaneous nephrolithotomy (mini-PCNL) in the treatment of 1-2 cm lower pole kidney stones. A total of 640 eligible adult patients will be enrolled across 20 high-volume urology centers in China, Russia, Turkey, and India. Participants will be randomly assigned to undergo either FANS-assisted flexible ureteroscopy or mini-PCNL. The primary outcome is the immediate stone-free rate (SFR) assessed by non-contrast CT within 72 hours after surgery. Secondary outcomes include SFR at 1 month, operative time, pain score, length of hospital stay, complication rates, and changes in health-related quality of life. The goal of this trial is to determine whether the less invasive FANS-assisted approach is non-inferior to mini-PCNL in terms of efficacy, while potentially offering advantages in postoperative recovery and safety.

Detailed description

The FLAME Trial (Flexible ureteroscopy for Lower pole stones And Mini-pErcutaneous nephrolithotomy) is an international, multicenter, prospective, randomized, controlled, non-inferiority study that aims to evaluate the safety and efficacy of flexible ureteroscopy assisted by a Flexible and Navigable Suction Ureteral Access Sheath (FANS) compared with mini-percutaneous nephrolithotomy (mini-PCNL) in the treatment of 1-2 cm lower pole renal stones. This trial will enroll 640 patients from 20 urology centers with substantial experience in endoscopic stone surgery, including hospitals in China, Russia, Turkey, and India. Eligible participants will be randomly assigned in a 1:1 ratio to either the FANS-assisted flexible ureteroscopy group or the mini-PCNL group. All patients will undergo preoperative imaging, intraoperative standardization, and postoperative follow-up according to the study protocol. The primary endpoint is the stone-free rate (SFR) within 72 hours postoperatively, evaluated by non-contrast-enhanced computed tomography (NCCT). Secondary endpoints include SFR at 1 month, operative time, length of hospital stay, postoperative pain (measured by VAS score), complication rates (graded by Clavien-Dindo classification), changes in renal function, and health-related quality of life (HRQoL). The FANS, developed to improve irrigation control and active stone fragment suction during flexible ureteroscopy, may provide better visualization, reduce intrarenal pressure, and shorten operative time. By directly comparing FANS-assisted fURS with mini-PCNL, the trial seeks to determine whether a less invasive method can achieve comparable outcomes in terms of stone clearance and complication rates.

Conditions

• Kidney Stones

Interventions

Type	Name	Description
PROCEDURE	Flexible ureteroscopy with FANS	The FANS with negative-pressure suction, enhancing intrarenal pressure control and fragment evacuation during flexible ureteroscopy.
PROCEDURE	Mini-percutaneous nephrolithotomy (mini-PCNL)	Mini-PCNL is performed under general anesthesia with less than 20 Fr access tract, using rigid nephroscopy and stone fragmentation under direct visualization. Postoperative drainage is provided via nephrostomy or ureteral stent as per protocol.

Timeline

• Start date: 2025-08-28
• Primary completion: 2026-02-28
• Completion: 2026-03-31
• First posted: 2025-09-08
• Last updated: 2025-09-08

Locations

1 site across 1 country: China