An interventional study of Storz single Lumen Ureteroscope and Dual Lumen Ureteroscope in Urolithiasis, sponsored by University of California, Irvine. Completed at 1 site in United States. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-03-13.
Sponsored by University of California, Irvine · Not applicable, Interventional, and Supportive care
Among 53 studies in Urolithiasis with a site in United States — 11 open to participants now, 15 under way, none of them phase 3. Urolithiasis · United States.
Among the 53 studies in Urolithiasis with a site in United States, this one is the 9th largest by enrollment of the 45 interventional ones that give a count, is one of 3 that started in 2014, is one of 33 with no phase, and was the 19th registered.
253 studies on the registry are indexed under Urolithiasis; 67 are open to participants now.
Browse Urolithiasis studies →11 of the 53 studies in Urolithiasis with a site in United States are open now. Recruiting first, the newest first:
Calyxo, Inc. · Sites in United States
Calyxo, Inc. · Sites in United States
University of Alabama at Birmingham · Sites in United States
Community Medical Center, Toms River, NJ · Sites in United States
Ryan L Steinberg · Sites in United States
A study can be open while its sites in United States have not opened yet or have stopped. Only those recruiting at a site in United States →
Of the 39 Urolithiasis studies recruiting now, 18 (46%) set no upper age limit and 13 (33%) stop at 75 or younger; 5 take children under 18; 4 take healthy volunteers.
This study: 18 Years and older · all sexes · healthy volunteers too.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
53 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 2 · Phase 2 6 · Phase 3 1 · Phase 4 5
First in 2003; this study’s year is marked. 3 started in 2014.
This study's enrollment of 156 is above the median of 100 across 182 interventional studies indexed under Urolithiasis.
Median enrollment 51 across the 45 interventional studies, 110 across the 8 observational. Of the 36 that completed or were terminated, 14 (39%) have results posted.
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8 of 53 have an industry lead sponsor. The 10 most frequent:
University of California, Irvine is the lead sponsor of 476 studies on the registry; 98 are open to participants now.
Of its 41 completed or terminated interventional studies of FDA-regulated products, 30 (73%) have results posted.
University of California, Irvine has 1 study filed under Urolithiasis — fewer than ten, so there is no comparison to draw.
4 of the studies in Urolithiasis with a site in United States that are under way reach primary completion within a year, 0 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT07225933Calyxo, Inc.A Retrospective, Multi-center Real-world Study of Steerable Ureteroscopic Renal Evacuation (SURE) Procedure With the CVAC® System | 2026-12-30 |
| NCT06974357Ryan L SteinbergEvaluation of Genetic Abnormalities Amongst Calcium Phosphate Stone Formers | 2027-03-01 |
| NCT06158620University of Texas Southwestern Medical CenterIntra-nasal Ketorolac for Acute Ureteral Stent-associated Pain Following Ureteroscopy for Stone Disease | 2027-04-01 |
| NCT07101809Calyxo, Inc.Trial of Ureteroscopy vs Steerable Continuous Flow Aspiration Technology | 2027-07 |
Among the 53 studies in Urolithiasis with a site in United States, from their registry updates:
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Urolithiasis (kidney stones) is a common disease process affecting people all across the world. Usually, if the stone size is small, it is able to pass through the urinary system and exit the bladder on its own with no treatment. However, when the size of the stone is bigger, it can get trapped in the kidney or the ureter, causing significant pain for the patient and potentially obstructing urine flow. If this occurs, surgical treatment is necessary for the removal of the stone. The surgical procedure often employed involves the use of a ureteroscope, which is a device that includes a camera and channels for working instruments such as a grasper and laser fiber to be placed during a procedure. Ureteroscopes that are currently in use are flexible and have the ability to treat stones that may otherwise be inaccessible in the kidney. Most flexible ureteroscopes in clinical use currently only have one channel therefore only allowing one instrument to be used at a time. Recently, a new type of ureteroscope has been introduced in the market that offers the advantage of having two working channels where two instruments can be inserted for use during stone treating procedure. This can potentially decrease procedure time for patients affected by kidney stones.
The purpose of this research is to compare the efficacy and safety of the ureteroscopes that have only one channel for instrument insertion with the newer ureteroscope that has two channels for utilization during stone treatment.
Study design
This study will be prospective, multi-institutional randomized controlled trial comparing single lumen and dual lumen ureteroscopes. Specifically, a new double-lumen ureteroscope will be compared in a multicenter trial with the currently existing single-lumen ureteroscopes in patients undergoing ureteroscopy for stones in the kidney and ureter.
Patient Recruitment and Randomization
All patients presenting to the Department of Urology at University of California, Irvine, University of Toronto and North Shore-LIJ Health System requiring a flexible ureteroscopy for treatment of their kidney or ureteral stone disease will be approached for enrolment in the study, assuming the inclusion and exclusion criteria detailed below are met. After discussion of the study with potential participants, interested parties will be given a copy of the consent form. The investigator will review and explain the consent form with the potential subject. All information about the study will be provided. Ample time will be given for individuals to ask questions regarding participation and to have questions answered prior to signing the consent form. If so desired, those interested will be given a copy of the consent form to take home so that they may have the opportunity to discuss participation further with family and/or advisors. If an individual chooses to enroll, the consent form will be signed before procedure begins. Once an individual joins the study and informed consent is obtained, the subject will receive a signed copy of the consent form. Individuals may chose not be enrolled in the study or may withdraw from the study at any time without repercussions to subsequent care.
Patients agreeing to participate in the study will be randomized on the day of surgery. Stratified block randomization will be utilized to balance the number of patients with different stone sizes (>1cm, \<1cm), kidney, proximal and distal ureteral stones between the two groups.
Device description
The Wolf Cobra Richard (Wolf Endoscopy, Vernon Hills, IL), a dual-lumen flexible ureteroscope is currently the only existing device with two working channels utilized in the operating room. Wolf Cobra has a shaft size of 9.9F. Each of the Cobra's two channels is 3.3 F in size (smaller compared with regular ureteroscopes 3.6F) but give a larger total cross-sectional area when two combined together. Atraumatic 6 Fr. distal tip dilates to a 9.9 Fr. sheath for ease of entry.
A dual-channel ureteroscope may provide several advantages. Having additional working channel enables better irrigation than a single-channel ureteroscope. It is achieved by continuous inflow and outflow, which might significantly, improve intraoperative visualization and maintains a clear field of view by efficient cleaning of blood, debris, and stone, even when utilizing multiple instruments simultaneously. Usually, multiple passes with different instruments requires the surgeon to reposition the ureteroscope in order to change the instruments which can potentially reduce efficiency and increase the length of operative time. The second working channel will allow the surgeon to use multiple instruments simultaneously while maintaining the flow and efficiently treat the stone or other pathology (Figure 1). This feature may offer technical advantages
Outcomes
Preoperatively, all patients will undergo a diagnostic imaging (CT, KUB, US) to identify the stone burden and location. Follow up imaging will be standardized across all participating institutions and will include CT or KUB imaging after the procedure to identify residual stones.
The primary outcome of the study will be the procedure time (minutes). This will be measured from the start of the endoscopic access to the end of the procedure including complete fragmentation and stone fragment removal.
The following data will also be recorded and serve as the secondary outcomes:
Additionally, patient demographics and clinical characteristics such as age, gender, Charlson comorbidity index, ASA, BMI, previous medical and surgical history will be collected. Stone characteristics such as size, location, density (HU) will be recorded. For each patient, three (width, length and depth) largest diameters of the stone will be measured from preoperative CT and volume will be calculated for accurate stone measurements. All preoperative and postoperative outcomes will be compared based on the stone characteristics such as size, location and type of stone (HU)
Deflection Angles
New single lumen and double lumen ureteroscopes will be used for the purpose of this study. To avoid any confounding factors, these scopes will be used exclusively on patients who are involved in the trial. Every week each ureteroscope will be assessed for maximal deflection, which is defined as the angle between the tangents of the deflection point and the tip of the ureteroscopes, as described by Monga and Parkin9,10. In order to calculate the angle, a photocopy of the ureteroscope while in maximal deflection will be taken. Both upward and downward angles of deflections will be measured three times and the mean value will be subsequently calculated for each type of ureteroscope prior to first usage. These measurements will be performed after each week of usage. After the last case of the study, the maximal angle of deflection for each of the two types of ureteroscopes will be measured again and will be compared to the measurement at the beginning of the study.
Fatigability Fatigability of a given ureteroscope is defined as decrease of the maximum amount of deflection of the tip4. The fatigability of each ureteroscope will be measured by subtracting the mean value of maximal deflection at the end of the study from the maximum deflection measured at the beginning of the study.
Subjective Assessments
After each procedure, the surgeon that performs the endoscopic procedure will be asked to rate the image quality of the scope by filling out a questionnaire from 1-10 (1 being poor and 10 being excellent visualization). These subjective assessments will be the investigators secondary outcomes. Additionally, the ease of deflection and overall scope performance will be asked.
Once each ureteroscope reaches a point where it will require repair, it will be shipped to the manufacturing company. The reason for repair will be recorded, and the type and cost of each repair will be documented.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Subjects enrolled in this study arm will have their procedure performed using the single lumen ureteroscopes. This scope is currently employed in clinical practice, including at UC Irvine Medical Center.
Device: Storz single Lumen Ureteroscope · Device: Dual Lumen Ureteroscope
Subjects enrolled in this study arm will have their procedure performed using the dual lumen ureteroscopes. This scope is currently employed in clinical practice, including at UC Irvine Medical Center.
Device: Storz single Lumen Ureteroscope · Device: Dual Lumen Ureteroscope
Single lumen, flexible scope for ureteroscopies
Also known as: Storz
Dual lumen, flexible scope for ureteroscopies
Also known as: Wolf Cobra
Time
The primary outcome of the proposed study will be the procedure time in minutes measured from the start of the endoscopic access to the end of the procedure including complete fragmentation and stone fragment removal.
Time frame: Day 1 (Day of procedure)
Complications
The secondary outcomes are going to be requirement for a second procedure, intraoperative complications, immediate postoperative complications, postoperative complications within 30 days of the procedure.
Time frame: Days 1-30
Time
Total Ureteroscopy time, stone fragmentation time, stone clearance time and overall procedure time.
Time frame: Days 1-30
Device efficacy
Surgeon's opinion and comfort (scale 1-10), visibility (1-10), and ureteroscope durability.
Time frame: Procedure day
Plan to share: No
No publications or documents are linked to this record.
Ran from Jul 2014 to primary completion in Apr 2021, 81 months.
Of 86 non-industry interventional studies with no phase under Urolithiasis, half reached primary completion within 20 months of starting (the median), counting those still running; a quarter within 11 and three quarters within 40. This study's 81 months is above that.
Counting every sponsor, half of 96 studies reached it within 19 months; a quarter within 11 and three quarters within 39.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in Mar 2025. You cannot join it, but the record below documents what was studied.
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University of California, Irvine →