NCT07798336

Brief Summary

This prospective, randomized, single-blinded, non-inferiority clinical trial will compare the clinical outcomes and cost-effectiveness of two mini-flexible ureteroscopes (6.3Fr and 7.5Fr) used during flexible ureteroscopy for the treatment of renal stones. Adult patients with renal stones up to 15 mm who are scheduled to undergo flexible ureteroscopy will be randomly assigned to one of the two study groups. The primary objectives are to compare stone-free rates and the ability to achieve primary renal access without preoperative ureteral stenting. Secondary outcomes include operative time, fluoroscopy use, ureteral trauma, postoperative stenting, pain, complications, emergency department visits, need for additional procedures, hospital stay, and cost-effectiveness. The results of this study are expected to provide high-quality evidence to guide the selection of mini-flexible ureteroscopes and improve the quality, safety, and value of surgical care for patients with kidney stones.

Trial Health

63
Monitor

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
308

participants targeted

Target at P75+ for not_applicable

Timeline
23mo left

Started Oct 2026

Typical duration for not_applicable

Geographic Reach
1 country

1 active site

Status
not yet recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

First Submitted

Initial submission to the registry

August 24, 2026

Completed
8 days until next milestone

First Posted

Study publicly available on registry

September 1, 2026

Completed
1 month until next milestone

Study Start

First participant enrolled

October 1, 2026

Completed
1.4 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

February 29, 2028

Expected
6 months until next milestone

Study Completion

Last participant's last visit for all outcomes

August 31, 2028

Last Updated

September 4, 2026

Status Verified

August 1, 2026

Enrollment Period

1.4 years

First QC Date

August 24, 2026

Last Update Submit

September 1, 2026

Conditions

Kidney StonesNephrolithiasisRenal Calculi

Keywords

Flexible ureteroscopyMini-flexible ureteroscopyMini ureteroscopeUreteroscopyRenal stonesKidney stonesNephrolithiasisEndourologyLaser lithotripsyThulium fiber laserRandomized controlled trialStone free rateCost effectivenessUreteroscope 6.3FrUreteroscope 7.5Fr

Outcome Measures

Primary Outcomes (2)

  • Stone Free Rate

    Stone-free status defined as the absence of residual stone fragments greater than 2 mm on non-contrast CT KUB

    1 month after surgery

  • Primary Renal Access Success Rate

    Successful passage of the flexible ureteroscope into the renal collecting system without the need for preoperative ureteral stenting

    Perioperative/Periprocedural

Secondary Outcomes (10)

  • Operative Time

    During surgery

  • Intraoperative Fluoroscopy Use

    During surgery

  • Intraoperative Ureteral Trauma as Assessed by the Traxer Ureteral Injury Scale

    Perioperative/Periprocedural

  • Postoperative Ureteral Stenting Rate

    Immediately after surgery

  • Postoperative Pain as Assessed by the Visual Analog Scale

    6, 24, and 48 hours after surgery

  • +5 more secondary outcomes

Study Arms (2)

6.3Fr Mini-Flexible Ureteroscope

EXPERIMENTAL

Participants randomized to this arm will undergo flexible ureteroscopy using a 6.3Fr mini-flexible ureteroscope for the treatment of renal stones according to the study protocol

Device: 6.3Fr Mini-Flexible Ureteroscope

7.5Fr Mini-Flexible Ureteroscope

ACTIVE COMPARATOR

Participants randomized to this arm will undergo flexible ureteroscopy using a 7.5Fr mini-flexible ureteroscope for the treatment of renal stones according to the study protocol

Device: 7.5Fr Mini-Flexible Ureteroscope

Interventions

6.3Fr Mini-Flexible UreteroscopeDEVICE

Use of a disposable 6.3Fr mini-flexible ureteroscope during flexible ureteroscopy for renal stone treatment

6.3Fr Mini-Flexible Ureteroscope
7.5Fr Mini-Flexible UreteroscopeDEVICE

Use of a disposable 7.5Fr mini-flexible ureteroscope during flexible ureteroscopy for renal stone treatment

7.5Fr Mini-Flexible Ureteroscope

Eligibility Criteria

Age18 Years+
Sexall
Healthy VolunteersNo
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • Scheduled to undergo flexible ureteroscopy for renal stones.
  • Renal stone size ≤15 mm in the greatest dimension.
  • No indwelling ureteral stent at the time of surgery.
  • Able and willing to provide written informed consent.

You may not qualify if:

  • Anatomical abnormalities of the urinary tract (e.g., ureteral stricture, horseshoe kidney, ectopic kidney).
  • Solitary kidney.
  • Pregnancy.
  • Stones located within a calyceal diverticulum.
  • Any condition that, in the opinion of the investigator, would interfere with study participation or follow-up.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Sault Area Hospital

Sault Ste. Marie, Ontario, P6B 0A8, Canada

Location

Related Publications (7)

  • Ebner B, Blajan I, Westphal JR, Papadopoulos I, Ivanova T, Karatas D, Happe M, Volz Y, Stief CG, Apfelbeck M, Chaloupka M. Feasibility and Safety of Primary Ureteroscopy with Single-Use Flexible Ureteroscope HU30M (6.3 Fr, HugeMed): An Initial Experience. Diagnostics (Basel). 2025 Oct 5;15(19):2522. doi: 10.3390/diagnostics15192522.

    PMID: 41095741BACKGROUND

  • Geavlete B, Ene C, Iordache V, Geavlete P. Initial Experience with the New Super Thin Single-use Pusen Flexible Ureteroscope 7.5 Fr in Renal Stones Endoscopic Treatment. Chirurgia (Bucur). 2021 May-Jun;116(3):354-360. doi: 10.21614/chirurgia.116.3.354.

    PMID: 34191717BACKGROUND

  • Hu H, Qin M, Yang L, Hu H, Qin G, Qiu M, Gao Y, Dou J, Wu T, Long P, Zhang W. Analysis of the effectiveness and safety of 7.5 Fr ultra-thin flexible ureteroscope combined with a tip-flexible suctioning ureteral access sheath for the treatment of kidney stones. Int Urol Nephrol. 2025 Mar;57(3):817-823. doi: 10.1007/s11255-024-04269-1. Epub 2024 Nov 9.

    PMID: 39521733BACKGROUND

  • Geavlete PA, Bulai CA, Multescu RD, Ene CV, Militaru A, Punga AA, Geavlete BF. Early clinical outcomes using a 6.3 Fr single use ureteroscope compared to a 7.5 Fr device. Sci Rep. 2025 May 2;15(1):15362. doi: 10.1038/s41598-025-00515-3.

    PMID: 40316636BACKGROUND

  • Alharran AM, Alajmi SA, Hussain AA, Alajmi MS, Hashim S, Alwazzan LT, Alaradi H. Efficacy and Safety of 6.3 Fr Versus 7.5 Fr Single-Use Flexible Ureteroscopes for Upper Urinary Tract Stones: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Medicina (Kaunas). 2025 Nov 26;61(12):2103. doi: 10.3390/medicina61122103.

    PMID: 41470105BACKGROUND

  • Assimos DG. Urolithiasis/Endourology. J Urol. 2021 Sep;206(3):765-767. doi: 10.1097/JU.0000000000001904. Epub 2021 Jun 11. No abstract available.

    PMID: 34111940BACKGROUND

  • Zhang L, Zhang X, Pu Y, Zhang Y, Fan J. Global, Regional, and National Burden of Urolithiasis from 1990 to 2019: A Systematic Analysis for the Global Burden of Disease Study 2019. Clin Epidemiol. 2022 Aug 15;14:971-983. doi: 10.2147/CLEP.S370591. eCollection 2022.

    PMID: 35996396BACKGROUND

MeSH Terms

Conditions

Kidney CalculiNephrolithiasis

Condition Hierarchy (Ancestors)

Kidney DiseasesUrologic DiseasesFemale Urogenital DiseasesFemale Urogenital Diseases and Pregnancy ComplicationsUrogenital DiseasesUrolithiasisUrinary CalculiMale Urogenital DiseasesCalculiPathological Conditions, AnatomicalPathological Conditions, Signs and Symptoms

Study Officials

  • Yasser A Noureldin, MD, PhD

    Urologist, Sault Area Hospital, Sault Ste. Marie, ON, Canada, and Assistant Professor of Urology, Northern Ontario School of Medicine University, ON, Canada

    PRINCIPAL INVESTIGATOR

Central Study Contacts

Yasser A Noureldin, MD, PhD

CONTACT

416-318-2239noureldiny@sah.on.ca

Asad O Naveed, MD

CONTACT

6478700880naveeda@sah.on.ca

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
DOUBLE
Who Masked
PARTICIPANT, OUTCOMES ASSESSOR
Masking Details
Participants and outcome assessors, including staff collecting postoperative outcomes and radiologists evaluating imaging studies, will be blinded to treatment allocation. Operating surgeons and operating room personnel will not be blinded because they must know which ureteroscope is being used during the procedure
Purpose
TREATMENT
Intervention Model
PARALLEL
Model Details: Participants will be randomized in a 1:1 ratio to undergo flexible ureteroscopy using either a 6.3Fr or a 7.5Fr mini-flexible ureteroscope. Outcomes will be compared between the two parallel groups
Sponsor Type
OTHER
Responsible Party
SPONSOR

Study Record Dates

First Submitted

August 24, 2026

First Posted

September 1, 2026

Study Start

October 1, 2026

Primary Completion (Estimated)

February 29, 2028

Study Completion (Estimated)

August 31, 2028

Last Updated

September 4, 2026

Record last verified: 2026-08

Data Sharing

IPD Sharing
Will not share

Individual participant data will not be made available to other researchers. This decision reflects applicable institutional policies, participant privacy and confidentiality requirements, ethical considerations, and the terms of informed consent. De-identified aggregate study results will be reported in accordance with applicable reporting requirements.

Locations

CA(1)