Ureteroscopy for Kidney Stones

(UPURS Trial)

Overseen By Heiko Yang, MD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of California, San Francisco

Disqualifiers: Transplant kidney, Conduit, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Approved in 5 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: Unknown

Duration: 3 months

100 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores the best way to manage painful kidney stones that are 5mm or larger. Researchers compare two approaches: performing an immediate procedure called ureteroscopy, which uses a tiny camera and tools to remove the stone, versus waiting to see if the stone passes naturally, with surgery as a backup if needed. The goal is to determine which method provides faster relief for symptoms like pain, nausea, or blood in the urine when patients visit the emergency room. The trial seeks participants diagnosed with a symptomatic ureteral stone during an emergency department visit. As an unphased trial, it offers participants the chance to contribute to important research that could enhance emergency care for kidney stones.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial coordinators or your doctor.

What prior data suggests that ureteroscopy is safe for managing ureteral stones?

Research has shown that ureteroscopy reliably treats kidney stones. It is often effective and generally well-tolerated by patients. Studies have demonstrated that ureteroscopy has a high success rate in removing stones.

For instance, one study found that semirigid ureteroscopy, which uses a thin tube with a camera and tools to break up stones, successfully cleared stones in about 78% of cases. This indicates that ureteroscopy is not only effective but also safe, with a relatively low risk of complications.

Flexible ureteroscopy, another type, has shown a lower risk of bleeding and requires a shorter hospital stay compared to other procedures, making it a safer choice for many patients.

Overall, evidence suggests that ureteroscopy is a safe and effective treatment for kidney stones, with a strong record of patient safety. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about ureteroscopy for kidney stones because it offers a direct, minimally invasive way to remove stones without the need for incisions or prolonged recovery time, unlike traditional methods such as shock wave lithotripsy or medication. This technique uses a thin scope to access the urinary tract, allowing for precise stone removal. The trial is comparing upfront ureteroscopy with a delayed approach, potentially helping refine patient care by determining the optimal timing for the procedure.

What evidence suggests that ureteroscopy is effective for managing symptomatic ureteral stones?

Research has shown that ureteroscopy effectively treats kidney stones, particularly those in the lower ureter, the tube connecting the kidney to the bladder. In this trial, participants in Group A will receive upfront ureteroscopy, while those in Group B will undergo observation with the option for delayed ureteroscopy. Studies have found that both semirigid and flexible ureteroscopy successfully remove stones, even in the upper ureter. With new laser technology, ureteroscopy has become even more effective, helping many patients become stone-free. This procedure is a dependable choice for those suffering from painful kidney stones. ^{2 3 6 7 8}

Who Is on the Research Team?

Thomas Chi, MD

Principal Investigator

University of California, San Francisco

Are You a Good Fit for This Trial?

The UPURS trial is for adults over 18 who come to the emergency department with symptoms like pain, nausea, vomiting, or blood in urine due to a ureteral stone that's at least 5mm big as seen on a CT scan. It's not for those with certain urinary structures, large stones unsuitable for URS, transplant kidneys, strong surgery preferences, need for stents due to other conditions, or untreated urinary infections.

Inclusion Criteria

You have a kidney stone that is 5 millimeters or larger as seen on a CT scan.

I am experiencing symptoms like pain, nausea, or blood in urine.

Presenting to the Emergency Department (ED)

Exclusion Criteria

My kidney stones cannot be treated with a scope through the urethra.

I prefer surgery or monitoring over other treatments.

I have a transplanted kidney.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

1-2 weeks

Treatment

Participants are randomized to either upfront ureteroscopy or observation with delayed intervention

3 months

Follow-up

Participants are monitored for pain, anxiety, and other outcomes after treatment

3 months

What Are the Treatments Tested in This Trial?

Interventions

• Ureteroscopy

Trial Overview This study compares two approaches: immediate ureteroscopy (a procedure using a scope to remove the stone) versus waiting and only performing the procedure if necessary later on. Participants are randomly assigned to one of these strategies when they show up at the hospital with kidney stone symptoms.

How Is the Trial Designed?

Group I: Group A (Upfront ureteroscopy) Active Control 1 Intervention

Group II: Group B (Observation/delayed ureteroscopy) Active Control 1 Intervention

Ureteroscopy is already approved in European Union, United States, Canada, Japan for the following indications:

Approved in European Union as Ureteroscopy for:

• Renal calculi
• Ureteral calculi
• Upper urinary tract calculi
• Nephrolithiasis
• Ureteral obstruction

Approved in United States as Ureteroscopy for:

• Kidney stones
• Ureteral stones
• Urinary tract obstruction
• Hematuria
• Ureteral tumors

Approved in Canada as Ureteroscopy for:

• Renal calculi
• Ureteral calculi
• Upper urinary tract calculi
• Nephrolithiasis
• Ureteral obstruction

Approved in Japan as Ureteroscopy for:

• Kidney stones
• Ureteral stones
• Urinary tract obstruction
• Hematuria
• Ureteral tumors

Who Is Running the Clinical Trial?

University of California, San Francisco

Lead Sponsor

Trials

2,636

Recruited

19,080,000+

University of Colorado, Denver

Collaborator

Trials

1,842

Recruited

3,028,000+

University of Colorado - Anschutz Medical Campus

Collaborator

Trials

9

Recruited

1,700+

State University of New York - Upstate Medical University

Collaborator

Trials

176

Recruited

27,600+

Published Research Related to This Trial

Semi-rigid ureteroscopy lithotripsy is highly effective for treating ureteral stones, achieving a success rate of 93.9% in a study of 232 patients, with most patients remaining stone-free after the procedure.

The procedure has a low incidence of major complications, with only 1.7% of patients experiencing serious issues that required conversion to open surgery, indicating it is a safe option for managing ureteral stones.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Semi-rigid Ureteroscopy for the Management of Ureteric Calculi: Our Experience and Complication Encountered. Tiwari, K., Upadhaya, AM., Kuwar, A., et al.[2020]

The study evaluated the learning curve for performing semi-rigid ureterorenolithotripsy in 60 procedures on patients with ureterolithiasis up to 1 cm, revealing significant improvements in surgical performance after the first 40 cases.

After completing 40 procedures, there was minimal further improvement in both the quality and efficiency of the surgery, indicating that this is the minimum number of cases needed to safely perform the procedure.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Learning curve of semi-rigid ureteroscopy for small calculi: how many cases are necessary? Ilias, D., Passerotti, CC., Pontes Junior, J., et al.[2023]

The study evaluated four new-generation flexible ureteroscopes, revealing that the Olympus XURF-P5 offers unique passive deflection capabilities and superior optical quality, making it a strong option for kidney stone removal.

The ACMI DUR-8 Elite provides secondary active deflection and has the shortest length among the tested ureteroscopes, while the Storz Flex-X2 and Wolf 7325.076 showed similar deflection capabilities and low torsion stiffness, indicating varied strengths among the devices.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A comparison of the physical properties of four new generation flexible ureteroscopes: (de)flection, flow properties, torsion stiffness, and optical characteristics. Paffen, ML., Keizer, JG., de Winter, GV., et al.[2016]

In a study of 185 patients undergoing flexible ureterorenoscopic holmium laser lithotripsy, the overall success rate for stone clearance was 90.7%, with particularly high success (96.5%) for stones sized 20 mm or smaller.

For stones larger than 20 mm, the stone-free rate dropped significantly, with only 58.3% achieving clearance after one treatment, indicating that 20 mm should be considered the maximum size for effective single-treatment outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Redefining the limits of flexible ureterorenoscopy. Hussain, M., Acher, P., Penev, B., et al.[2022]

Flexible ureteroscopy combined with holmium laser treatment achieved a high success rate of 97.2% for treating renal stones smaller than 2 cm, with a stone-free rate of 94.3% after 8 weeks.

The procedure had a manageable complication rate of 12.9%, with no serious adverse outcomes reported, indicating it is a safe option for patients with small renal calculi.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Improved effectiveness and safety of flexible ureteroscopy for renal calculi ( Chen, S., Xu, B., Liu, N., et al.[2020]

Flexible ureteroscopy without the use of a double-J stent post-surgery (Post-F group) was shown to be safe and effective for treating kidney and upper ureteral stones, with no stent-related complications observed during follow-up.

While the operation time was similar across all groups, the Pre-F group (with postoperative stenting) experienced a higher incidence of ureteral injuries, indicating that avoiding postoperative stenting may reduce certain complications.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The study of double-J stent free mode of flexible ureteroscopy and laser lithotripsy: a single centre experience. Xu, M., Han, X., Zhu, J., et al.[2023]

In a study of 4500 retrograde flexible ureteroscopic procedures for kidney stones, overall complications occurred in 18.9% of cases, with most being mild and manageable.

The use of a ureteral access sheath significantly reduced the risk of septic complications, highlighting its protective role during the procedure.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Morbidity of Retrograde Flexible Ureteral Approach for Pyelo-Caliceal Stones - A Retrospective Review of 4500 Procedures. Geavlete, PA., Mulţescu, R., Geavlete, BF.[2020]

Flexible ureterorenoscopy (f-URS) is equally effective for treating kidney stones in obese patients (BMI ≥30 kg/m²) compared to normal weight patients (BMI <25 kg/m²), with success rates of 68% and 67.4% respectively, indicating that obesity does not negatively impact treatment outcomes.

The procedure also showed similar postoperative morbidity rates (2.44%) across both groups, suggesting that f-URS is a safe option for patients regardless of their body mass index.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Comparative study of the treatment of renal stones with flexible ureterorenoscopy in normal weight, obese, and morbidly obese patients. Doizi, S., Letendre, J., Bonneau, C., et al.[2014]

Flexible ureteroscopy has significantly advanced the surgical management of kidney stones over the past 30 years, allowing for both diagnostic and therapeutic interventions in the upper urinary tract.

The use of improved tools, such as Holmium: YAG laser lithotripsy, has expanded the indications for flexible ureteroscopy, making it effective for treating not only urolithiasis (kidney stones) but also urothelial tumors.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Retrograde intrarenal surgery: An expanding role in treatment of urolithiasis. Rodríguez-Monsalve Herrero, M., Doizi, S., Keller, EX., et al.[2020]

Percutaneous nephrolithotomy (PCNL) has a higher initial stone-free rate for treating intermediate-size renal stones (2-3 cm) compared to retrograde flexible ureteroscopy (FURS), but FURS can achieve comparable final stone-free rates after additional treatments.

PCNL is associated with a higher rate of intraoperative complications and longer hospital stays, while FURS presents a safer alternative with fewer complications, making it a viable option for patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Comparison of retrograde flexible ureteroscopy and percutaneous nephrolithotomy in treating intermediatesize renal stones (2-3cm): a meta-analysis and systematic review. Zewu, Z., Cui, Y., Feng, Z., et al.[2020]

Flexible ureteroscopy has become a popular and effective treatment for kidney stones due to advancements in technology, including fiberoptic and digital ureteroscopes and holmium laser lithotripters.

This method offers high stone-free rates and low morbidity, enhancing patient safety and comfort during minimally invasive procedures.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Contemporary ureteroscopic management of renal stones. Proietti, S., Knoll, T., Giusti, G.[2018]

In a study evaluating 6 different flexible ureteroscopes, larger caliber tools significantly reduced the active deflection capabilities of the instruments, particularly when using non-nitinol tools, which can impact the effectiveness of treating upper urinary tract stones.

Irrigation flow through the working channel was negatively affected by the diameter of the tools inserted; tools larger than 3 French completely blocked the flow, highlighting the importance of tool selection for maintaining visibility during procedures.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Impact on active scope deflection and irrigation flow of all endoscopic working tools during flexible ureteroscopy. Pasqui, F., Dubosq, F., Tchala, K., et al.[2022]

This study identified 12 major complications from retrograde ureteroscopy procedures, with 8 cases of kidney injury and other serious issues like ureter avulsion and acute sepsis, emphasizing the potential risks associated with these common procedures.

The findings highlight the importance of careful postoperative monitoring and active treatment of complications to reduce risks of morbidity and mortality, suggesting that standardized reporting and classification of complications should be routinely implemented.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Life-threatening complications after ureteroscopy for urinary stones: survey and systematic literature review. Cindolo, L., Castellan, P., Primiceri, G., et al.[2022]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10674128/

Semirigid vs Flexible Ureteroscopy in the Management of ... It excels at treating distal and difficult stones but has a lower efficacy with larger stones and often requires longer procedure times. The choice between ...

2. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC4220357/

Ureteroscopy and stones: Current status and future ... More distal stone have higher success rates when treated with rigid ureteroscopy, compared to the more proximal stones[24].

3. bmcurol.biomedcentral.com bmcurol.biomedcentral.com/articles/10.1186/s12894-024-01647-w

For upper ureteral stone, semirigid ureteroscopy or flexible ... Flexible ureteroscopy and semirigid ureteroscopy both had high stone clearance rate in the treatment for upper ureteral stones.

4. sciencedirect.com sciencedirect.com/science/article/pii/S2214388224000195

Review Flexible ureteroscopic treatment of kidney stones Flexible ureteroscopy (fURS) has become a widely accepted and effective technique for treating kidney stones. With the development of new laser systems, the ...

5. jurolsurgery.org jurolsurgery.org/articles/effectiveness-of-second-look-flexible-ureteroscopy-to-achieve-a-true-stone-free-status-in-retrograde-intrarenal-surgery/jus.galenos.2021.2021.0092

Effectiveness of Second-look Flexible Ureteroscopy to ... Stone-free rate after RIRS for groups 1 and 2 were 37.25% (n=19/51) and 40.8% (n=51/125), respectively. The stone-free rates improved to 93.6% ( ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC11433351/

Clinical Outcomes and Safety Assessment of Flexible ... Ureteroscopy stands as a formidable approach for managing urinary stones, offering versatility in addressing calculi within both the ureter and ...

7. sciencedirect.com sciencedirect.com/science/article/abs/pii/S0302283825003434

Original Article Flexible Ureteroscopy with a ... FANS f-URS had a noninferior SFR in comparison to mPCNL for 2–3 cm renal stones, with lower risk of bleeding risk, shorter hospitalization, and superior QoL.

8. sciencedirect.com sciencedirect.com/science/article/pii/S2666168324010929

Efficacy and Safety of Semirigid Ureteroscopy Combined ... The main results of this systematic review suggested that semirigid ureteroscopy combined with laser lithotripsy achieves a one-time SFR of approximately 78% in ...