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

NCT ID: NCT07159035

Last Updated: 2025-09-08

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

Get a concise snapshot of the trial, including recruitment status, study phase, enrollment targets, and key timeline milestones.

Recruitment Status

RECRUITING

Clinical Phase

NA

Total Enrollment

640 participants

Study Classification

INTERVENTIONAL

Study Start Date

2025-08-28

Study Completion Date

2026-03-31

Brief Summary

Review the sponsor-provided synopsis that highlights what the study is about and why it is being conducted.

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

Dive into the extended narrative that explains the scientific background, objectives, and procedures in greater depth.

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

See the medical conditions and disease areas that this research is targeting or investigating.

Kidney Stones

Study Design

Understand how the trial is structured, including allocation methods, masking strategies, primary purpose, and other design elements.

Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Participants will be randomized in a 1:1 ratio to undergo either FANS-assisted flexible ureteroscopy or mini-percutaneous nephrolithotomy for the treatment of 1-2 cm lower pole renal stones. This is a multicenter, international, randomized, non-inferiority trial.
Primary Study Purpose

TREATMENT

Blinding Strategy

DOUBLE

Investigators Outcome Assessors
Blinding of participants and surgeons is not feasible due to the obvious procedural differences between flexible ureteroscopy with FANS and mini-percutaneous nephrolithotomy. However, radiologists assessing postoperative CT scans will be blinded to treatment allocation. Clinical follow-up assessments will be performed by independent investigators who did not participate in the surgeries. Statistical analysis will also be conducted in a blinded manner, with group assignments concealed from the analyst until data interpretation is complete.

Study Groups

Review each arm or cohort in the study, along with the interventions and objectives associated with them.

FANS-fURS Group

Patients assigned to this group will undergo flexible ureteroscopy with FANS (Flexible endoscopy-Assisted Negative-pressure Suction Sheath). The FANS facilitates direct stone visualization, fragmentation, suction, and removal under controlled pressure conditions.

Group Type EXPERIMENTAL

Flexible ureteroscopy with FANS

Intervention Type PROCEDURE

The FANS with negative-pressure suction, enhancing intrarenal pressure control and fragment evacuation during flexible ureteroscopy.

mini-PCNL Group

Patients in this group will receive mini-percutaneous nephrolithotomy (mini-PCNL) via less than 20 Fr percutaneous tracts.

Group Type ACTIVE_COMPARATOR

Mini-percutaneous nephrolithotomy (mini-PCNL)

Intervention Type PROCEDURE

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.

Interventions

Learn about the drugs, procedures, or behavioral strategies being tested and how they are applied within this trial.

Flexible ureteroscopy with FANS

The FANS with negative-pressure suction, enhancing intrarenal pressure control and fragment evacuation during flexible ureteroscopy.

Intervention Type 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.

Intervention Type PROCEDURE

Eligibility Criteria

Check the participation requirements, including inclusion and exclusion rules, age limits, and whether healthy volunteers are accepted.

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.
Minimum Eligible Age

18 Years

Maximum Eligible Age

75 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

Meet the organizations funding or collaborating on the study and learn about their roles.

Shengjing Hospital

OTHER

Sponsor Role collaborator

The Third Xiangya Hospital of Central South University

OTHER

Sponsor Role collaborator

Saint Petersburg State University Hospital

UNKNOWN

Sponsor Role collaborator

Fortune Urology Clinic

UNKNOWN

Sponsor Role collaborator

Zhongda Hospital

OTHER

Sponsor Role collaborator

Tongji Hospital

OTHER

Sponsor Role collaborator

The First Affiliated Hospital Hengyang Medical School

UNKNOWN

Sponsor Role collaborator

First Affiliated Hospital of Ningbo University

NETWORK

Sponsor Role collaborator

The Sixth Affiliated Hospital of Guangzhou Medical University

OTHER

Sponsor Role collaborator

The First Affiliated Hospital of Xiamen University

OTHER

Sponsor Role collaborator

Dehong People's Hospital

UNKNOWN

Sponsor Role collaborator

People's Hospital of Nanhai District, Foshan

UNKNOWN

Sponsor Role collaborator

Huadu District People's Hospital of Guangzhou

OTHER

Sponsor Role collaborator

Jiangmen Central Hospital

OTHER

Sponsor Role collaborator

Baoshan No.2 People's Hospital

UNKNOWN

Sponsor Role collaborator

Guizhou Provincial People's Hospital

OTHER

Sponsor Role collaborator

Xinhua Hospital, Shanghai Jiao Tong University School of Medicine

OTHER

Sponsor Role collaborator

Tianjin Medical University Second Hospital

OTHER

Sponsor Role collaborator

Ankara University

OTHER

Sponsor Role collaborator

The First Affiliated Hospital of Guangzhou Medical University

OTHER

Sponsor Role lead

Responsible Party

Identify the individual or organization who holds primary responsibility for the study information submitted to regulators.

Guohua Zeng

Vice-president

Responsibility Role PRINCIPAL_INVESTIGATOR

Locations

Explore where the study is taking place and check the recruitment status at each participating site.

The First Affiliated Hospital of Guangzhou Medical University

Guangzhou, Guangdong, China

Site Status RECRUITING

Countries

Review the countries where the study has at least one active or historical site.

China

Central Contacts

Reach out to these primary contacts for questions about participation or study logistics.

Wei Zhu, Ph.D.

Role: CONTACT

+8613622754991

Facility Contacts

Find local site contact details for specific facilities participating in the trial.

Guohua Zeng, Ph.D.

Role: primary

13622754991

Wei Zhu, Ph.D.

Role: backup

13622754991

References

Explore related publications, articles, or registry entries linked to this study.

Skolarikos A, Geraghty R, Somani B, Tailly T, Jung H, Neisius A, Petrik A, Kamphuis GM, Davis N, Bezuidenhout C, Lardas M, Gambaro G, Sayer JA, Lombardo R, Tzelves L. European Association of Urology Guidelines on the Diagnosis and Treatment of Urolithiasis. Eur Urol. 2025 Jul;88(1):64-75. doi: 10.1016/j.eururo.2025.03.011. Epub 2025 Apr 22.

Reference Type BACKGROUND
PMID: 40268592 (View on PubMed)

Other Identifiers

Review additional registry numbers or institutional identifiers associated with this trial.

ES-2025-181

Identifier Type: -

Identifier Source: org_study_id

More Related Trials

Additional clinical trials that may be relevant based on similarity analysis.

Management of Medium Sized Renal Stones
NCT06720311 NOT_YET_RECRUITING NA