An interventional study of 6.3Fr Mini-Flexible Ureteroscope and 7.5Fr Mini-Flexible Ureteroscope in Kidney Stones, Nephrolithiasis and Renal Calculi, sponsored by Sault Area Hospital. Not yet recruiting at 1 site in Canada. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-04.
Sponsored by Sault Area Hospital · Not applicable, Interventional, and Treatment
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.
Renal stone disease is a common condition with an increasing global incidence. Flexible ureteroscopy has become one of the standard treatments for renal stones because it provides excellent stone clearance with a minimally invasive approach. Recent technological advances have led to the development of mini-flexible ureteroscopes with smaller diameters, which may facilitate easier access to the kidney while reducing ureteral trauma and the need for preoperative ureteral stenting.
Although both 6.3Fr and 7.5Fr mini-flexible ureteroscopes are currently available for clinical use, there is limited high-level evidence comparing their clinical performance and cost-effectiveness. This prospective, randomized, single-blinded, non-inferiority trial aims to compare these two ureteroscope sizes in adult patients undergoing flexible ureteroscopy for renal stones.
Eligible 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. All procedures will be performed using standardized surgical techniques by experienced endourologists.
The primary outcomes are stone-free rate at one month after surgery and successful primary renal access without preoperative ureteral stenting. Secondary outcomes include operative time, fluoroscopy utilization, intraoperative ureteral trauma, postoperative ureteral stenting, postoperative pain, complications classified using the Clavien-Dindo system, emergency department visits, hospital length of stay, need for secondary procedures, and cost-effectiveness from the hospital payer perspective.
The investigators hypothesize that the 6.3Fr mini-flexible ureteroscope will improve primary renal access while reducing ureteral trauma, fluoroscopy exposure, postoperative stenting, and overall healthcare costs without compromising stone-free rates. The findings of this study may help establish evidence-based recommendations for selecting mini-flexible ureteroscopes and optimize the surgical management of patients with renal stone disease.
509 studies on the registry are indexed under Kidney Calculi; 146 are open to participants now.
This study's planned enrollment of 308 is above the median of 86 across 391 interventional studies indexed under Kidney Calculi.
Browse Kidney Calculi studies →Sault Area Hospital is the lead sponsor of 2 studies on the registry; 1 is open to participants now.
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Inclusion Criteria: * Adults aged 18 years or older.
Exclusion Criteria: * Active urinary tract infection.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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
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
Use of a disposable 6.3Fr mini-flexible ureteroscope during flexible ureteroscopy for renal stone treatment
Use of a disposable 7.5Fr mini-flexible ureteroscope during flexible ureteroscopy for renal stone treatment
Stone Free Rate
Stone-free status defined as the absence of residual stone fragments greater than 2 mm on non-contrast CT KUB
Time frame: 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
Time frame: Perioperative/Periprocedural
Operative Time
Total operative time measured from insertion of the ureteroscope until completion of the procedure
Time frame: During surgery
Intraoperative Fluoroscopy Use
Fluoroscopy utilization during the procedure, including fluoroscopy time
Time frame: During surgery
Intraoperative Ureteral Trauma as Assessed by the Traxer Ureteral Injury Scale
Ureteral trauma will be assessed using the Traxer Ureteral Injury Scale, graded from 0 to 3, where Grade 0 indicates no observable ureteral injury and Grade 3 indicates the most severe ureteral injury. Higher scores indicate greater severity of ureteral injury.
Time frame: Perioperative/Periprocedural
Postoperative Ureteral Stenting Rate
Percentage of participants requiring ureteral stent placement at the end of surgery
Time frame: Immediately after surgery
Postoperative Pain as Assessed by the Visual Analog Scale
Postoperative pain will be assessed using the Visual Analog Scale, ranging from 0 to 10, where 0 represents no pain and 10 represents the worst possible pain. Higher scores indicate greater pain.
Time frame: 6, 24, and 48 hours after surgery
Postoperative Complications
Complications graded using the Clavien-Dindo Classification
Time frame: Up to 30 days after surgery
Emergency Department Visits
Emergency department visits related to the procedure
Time frame: Within 2 weeks after surgery
Hospital Length of Stay
Length of hospital stay measured in hours from admission for the index ureteroscopy procedure to hospital discharge.
Time frame: Perioperative/Periprocedural
Need for Secondary Procedures
Requirement for additional stone-related procedures
Time frame: Up to 1 month after surgery
Incremental Cost-Effectiveness Ratio Comparing 6.3Fr and 7.5Fr Mini-Flexible Ureteroscopes
The incremental cost-effectiveness ratio (ICER) will compare the additional direct medical cost associated with the 6.3Fr versus 7.5Fr mini-flexible ureteroscope relative to the incremental clinical effectiveness. Direct medical costs will include ureteroscope acquisition costs, repair costs, procedure-related disposables, operating room time, hospital stay, management of complications, readmissions, and secondary procedures. Clinical effectiveness will be assessed primarily using stone-free and successful primary access outcomes.
Time frame: From surgery through 30 days after surgery
Plan to share: No — 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.
This study is not yet recruiting, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
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Sault Area Hospital