Flexible Ureteroscopy With a Flexible and Navigable Suction Ureteral Access Sheath Versus Mini-Percutaneous Nephrolithotomy for 1-2 cm Lower Pole Kidney Stones

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.

Conditions

• Kidney Stones

Interventions

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.

Sponsors & Collaborators

• Shengjing Hospital

  collaborator OTHER

• The Third Xiangya Hospital of Central South University

  collaborator OTHER

• Saint Petersburg State University Hospital

  collaborator UNKNOWN

• Fortune Urology Clinic

  collaborator UNKNOWN

• Zhongda Hospital

  collaborator OTHER

• Tongji Hospital

  collaborator OTHER

• The First Affiliated Hospital Hengyang Medical School

  collaborator UNKNOWN

• First Affiliated Hospital of Ningbo University

  collaborator NETWORK

• The Sixth Affiliated Hospital of Guangzhou Medical University

  collaborator OTHER

• The First Affiliated Hospital of Xiamen University

  collaborator OTHER

• Dehong People's Hospital

  collaborator UNKNOWN

• People's Hospital of Nanhai District, Foshan

  collaborator UNKNOWN

• Huadu District People's Hospital of Guangzhou

  collaborator OTHER

• Jiangmen Central Hospital

  collaborator OTHER

• Yunnan Baoshan Second People's Hospital

  collaborator OTHER

• Guizhou Provincial People's Hospital

  collaborator OTHER

• Xinhua Hospital, Shanghai Jiao Tong University School of Medicine

  collaborator OTHER

• Tianjin Medical University Second Hospital

  collaborator OTHER

• Ankara University

  collaborator OTHER

• The First Affiliated Hospital of Guangzhou Medical University

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2025-08-28

Primary Completion

2026-05-01

Completion

2026-06-30

Countries

• China

Study Locations