NephrolithiasisVA-UAS vs tradNCT06547632
ClearPetra™ Vacuum-assisted Ureteral Access Sheath vs Traditional Approach
A study testing ClearPetra Ureteral access sheath in people with Nephrolithiasis and Kidney Stone, run by University of Kansas Medical Center at 1 site in United States.
Trial summary
Ureteroscopy has been considered the best approach when treating renal stones smaller than 2 cm. This procedure is usually performed together with ureteral access sheaths, which helps protect the ureter mucosa and lowers intrarenal pressure. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Nephrolithiasis, Kidney Stone
- What is being tested?
- ClearPetra Ureteral access sheath
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 3 participants
- Where
- 1 siteUnited States
- Study dates
- 31 Jul 2025to 27 Feb 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Males or females over18 years of age
- Undergoing primary flexible ureteroscopy for retrograde intrarenal surgery
- Total stone burden between 1.0 to 2.5 cm
Who cannot join
- Undergoing bilateral stone treatment during the same procedure
- Patients with known genitourinary anatomical abnormalities
- Uncorrected coagulopathy
- Patients with urinary diversions
- Chronic external urinary catheters
- Women who are pregnant
- Immunosuppressed patients
- Non-elective procedures
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Kansas Medical Center
Kansas City, Kansas, 66160
About this study
Official title: ClearPetra™ Vacuum-assisted Ureteral Access Sheath vs Traditional Approach in Retrograde Intrarenal Surgery. A Randomized Controlled Trial
Ureteroscopy has been considered the best approach when treating renal stones smaller than 2 cm. This procedure is usually performed together with ureteral access sheaths, which helps protect the ureter mucosa and lowers intrarenal pressure.
Recently, a new vacuum-assisted ureteral access sheath called ClearPetra has entered US market and allows for continuous stone fragmentation and aspiration.
Because there is little information on comparing this device with traditional approach (no sheath or non-vacuum-assisted sheath) in American population, we aim to compare those devices in terms of their ability to clear the kidney from kidney stones, as well as reduce infection rates postoperatively.
Read the detailed description
Retrograde intrarenal surgery (RIRS) is now considered gold-standard for treatment of renal stones smaller than 2 cm. This procedure often employs a ureteral access sheath (UAS), as it helps to reduce intrarenal pressure and protects the ureter mucosa when basketing is required. However, the challenge imposed by residual stone fragments and sepsis remains. Additionally, natural elimination of residual stone fragments may induce renal colic, hematuria an even the potential for new stone development. Recently, a new vacuum-assisted ureteral access sheath (VA-UAS) named ClearPetra™ provides concomitant stone fragmentation and aspiration.
The new ClearPetra™ vacuum assisted ureteral access sheath allows simultaneous fragmentation and extraction of stones. It is a disposable access sheath equipped with a continuous flow aspiration mechanism. Previous studies have demonstrated the safety and effectiveness of ClearPetra™ in RIRS Comprehensive comparative investigations between ClearPetra™ and traditional UAS in RIRS are lacking in American population. We aim to compare the outcomes of using VA-UAS (ClearPetra™) or traditional approach (no sheath or non-vacuum-assisted sheath) to treat patients with stone burden between 1.0 - 2.5 cm.
- Conditions
- Nephrolithiasis, Kidney Stone
- Being tested
- ClearPetra Ureteral access sheath
- Keywords
- Nephrolithiasis, Kidney Stone, ClearPetra, Ureteral access sheath
- Medical subject headings
- Nephrolithiasis, Kidney Calculi
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ClearPetra Ureteral access sheathDevice
Patients will be randomly assigned (1:1) to vacuum-assisted (ClearPetra) or traditional approach group for retrograde intrarenal surgery according to standard of care.
| Study group | Role | What they receive |
|---|---|---|
| 1. RIRS WITH VACUUM-ASSISTED URETERAL ACCESS SHEATH | Active comparator | In Arm 1, participants will undergo RIRS with ClearPetra™ vacuum-assisted ureteral access sheath.
Participants will undergo RIRS per standard of care. Receives: Device: ClearPetra Ureteral access sheath |
| 2. RIRS WITH TRADITIONAL APPROACH | No intervention | In Arm 2, participants will undergo RIRS a traditional approach (no sheath or non-vacuum-assisted sheath). The treating investigator will decide whether to use a regular UAS based on their preference and/or availability. * No ureteral access sheath * Navigator™ Ureteral Access Sheath 11/13 Fr (Boston Scientific®) * Navigator™ Ureteral Access Sheath 12/14 Fr (Boston Scientific®) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Stone Free Status between ClearPetra and traditional approach
Stone free is defined as no residual stones \>2mm in post operative CT scan
Measured: 90 days
Secondary outcomes (2)
Total operative time between ClearPetra and traditional approach
Time from scope insertion to scope removal from the patient
Measured: 1 day
Urinary tract infection between ClearPetra and traditional approach
Data collection searching for urine tract infection signs, symptoms, antibiotic administration and culture
Measured: 30 days of procedure
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Aug 2024
- Study start31 Jul 2025
- Primary completion21 Jan 2026
- Study completion27 Feb 2026
Why it stopped: Change in guidelines
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for NephrolithiasisStudies of the same condition, open and under way.
- More trials run by University of Kansas Medical CenterThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Parallel assignment
- Masking
- None (open label)
- Enrolment
- 3 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Kansas Medical Center
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Wilson Molina, University of Kansas Medical Center
- Investigators
- Wilson Molina, MD, Principal investigator, Study Principal Investigator
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06547632
- Sponsor's protocol ID
- STUDY00161273
- Acronym
- VA-UAS vs trad
- Status last verified
- May 2026
- First submitted
- 7 Aug 2024
- Last updated
- 6 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- No
Publications
Tonyali S. Suctioning ureteral access sheath use in flexible ureteroscopy might decrease operation time and prevent infectious complications. World J Urol. 2019 Feb;37(2):393-394. doi: 10.1007/s00345-018-2510-5. Epub 2018 Sep 26. No abstract available.
PubMed 30259124Assimos D, Krambeck A, Miller NL, Monga M, Murad MH, Nelson CP, Pace KT, Pais VM Jr, Pearle MS, Preminger GM, Razvi H, Shah O, Matlaga BR. Surgical Management of Stones: American Urological Association/Endourological Society Guideline, PART I. J Urol. 2016 Oct;196(4):1153-60. doi: 10.1016/j.juro.2016.05.090. Epub 2016 May 27.
PubMed 27238616Chen Y, Zheng L, Lin L, Li C, Gao L, Ke L, Kuang R, Chen J. A novel flexible vacuum-assisted ureteric access sheath in retrograde intrarenal surgery. BJU Int. 2022 Nov;130(5):586-588. doi: 10.1111/bju.15873. Epub 2022 Sep 6. No abstract available.
PubMed 35986898
Study at a glance
From the registry record, last updated by the sponsor on 6 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- ClearPetra™ Vacuum-assisted Ureteral Access Sheath vs Traditional Approach in Retrograde Intrarenal Surgery. A Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT06547632
- Acronym / sponsor ID
- VA-UAS vs trad / STUDY00161273
- Conditions
- Nephrolithiasis, Kidney Stone
- Keywords
- Nephrolithiasis, Kidney Stone, ClearPetra, Ureteral access sheath
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Change in guidelines
- Enrolment
- 3 participants (actual)
- Lead sponsor
- University of Kansas Medical CenterUniversity, hospital or other
- Study start
- 31 Jul 2025 (actual)
- Primary completion
- 21 Jan 2026 (actual)
- Study completion
- 27 Feb 2026 (actual)
- First posted
- 9 Aug 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Ureteroscopy has been considered the best approach when treating renal stones smaller than 2 cm. This procedure is usually performed together with ureteral access sheaths, which helps protect the ureter mucosa and lowers intrarenal pressure.
Recently, a new vacuum-assisted ureteral access sheath called ClearPetra has entered US market and allows for continuous stone fragmentation and aspiration.
Because there is little information on comparing this device with traditional approach (no sheath or non-vacuum-assisted sheath) in American population, we aim to compare those devices in terms of their ability to clear the kidney from kidney stones, as well as reduce infection rates postoperatively.
Detailed description
Retrograde intrarenal surgery (RIRS) is now considered gold-standard for treatment of renal stones smaller than 2 cm. This procedure often employs a ureteral access sheath (UAS), as it helps to reduce intrarenal pressure and protects the ureter mucosa when basketing is required. However, the challenge imposed by residual stone fragments and sepsis remains. Additionally, natural elimination of residual stone fragments may induce renal colic, hematuria an even the potential for new stone development. Recently, a new vacuum-assisted ureteral access sheath (VA-UAS) named ClearPetra™ provides concomitant stone fragmentation and aspiration.
The new ClearPetra™ vacuum assisted ureteral access sheath allows simultaneous fragmentation and extraction of stones. It is a disposable access sheath equipped with a continuous flow aspiration mechanism. Previous studies have demonstrated the safety and effectiveness of ClearPetra™ in RIRS Comprehensive comparative investigations between ClearPetra™ and traditional UAS in RIRS are lacking in American population. We aim to compare the outcomes of using VA-UAS (ClearPetra™) or traditional approach (no sheath or non-vacuum-assisted sheath) to treat patients with stone burden between 1.0 - 2.5 cm.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Parallel assignment
| Arm | Type | Receives |
|---|---|---|
| 1. RIRS WITH VACUUM-ASSISTED URETERAL ACCESS SHEATH | Active comparator | Device: ClearPetra Ureteral access sheathIn Arm 1, participants will undergo RIRS with ClearPetra™ vacuum-assisted ureteral access sheath. Participants will undergo RIRS per standard of care. |
| 2. RIRS WITH TRADITIONAL APPROACH | No intervention | –In Arm 2, participants will undergo RIRS a traditional approach (no sheath or non-vacuum-assisted sheath). The treating investigator will decide whether to use a regular UAS based on their preference and/or availability. * No ureteral access sheath * Navigator™ Ureteral Access Sheath 11/13 Fr (Boston Scientific®) * Navigator™ Ureteral Access Sheath 12/14 Fr (Boston Scientific®) |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Males or females over18 years of age
- Undergoing primary flexible ureteroscopy for retrograde intrarenal surgery
- Total stone burden between 1.0 to 2.5 cm
Key exclusion criteria (8 listed)
- Undergoing bilateral stone treatment during the same procedure
- Patients with known genitourinary anatomical abnormalities
- Uncorrected coagulopathy
- Patients with urinary diversions
- Chronic external urinary catheters
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ClearPetra Ureteral access sheathPatients will be randomly assigned (1:1) to vacuum-assisted (ClearPetra) or traditional approach group for retrograde intrarenal surgery according to standard of care. | Device | 1. RIRS WITH VACUUM-ASSISTED URETERAL ACCESS SHEATH |
Primary outcome
Stone Free Status between ClearPetra and traditional approach
Time frame: 90 days
Stone free is defined as no residual stones \>2mm in post operative CT scan
2 secondary outcomes
Total operative time between ClearPetra and traditional approach
Time frame: 1 day
Urinary tract infection between ClearPetra and traditional approach
Time frame: 30 days of procedure
Results and safety
The study was stopped early (reason given: Change in guidelines). Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 May 2026.
- Background: PubMed 30259124Tonyali S. Suctioning ureteral access sheath use in flexible ureteroscopy might decrease operation time and prevent infectious complications. World J Urol. 2019 Feb;37(2):393-394. doi: 10.1007/s00345-018-2510-5. Epub 2018 Sep 26. No abstract available.
- Background: PubMed 27238616Assimos D, Krambeck A, Miller NL, Monga M, Murad MH, Nelson CP, Pace KT, Pais VM Jr, Pearle MS, Preminger GM, Razvi H, Shah O, Matlaga BR. Surgical Management of Stones: American Urological Association/Endourological Society Guideline, PART I. J Urol. 2016 Oct;196(4):1153-60. doi: 10.1016/j.juro.2016.05.090. Epub 2016 May 27.
- Background: PubMed 35986898Chen Y, Zheng L, Lin L, Li C, Gao L, Ke L, Kuang R, Chen J. A novel flexible vacuum-assisted ureteric access sheath in retrograde intrarenal surgery. BJU Int. 2022 Nov;130(5):586-588. doi: 10.1111/bju.15873. Epub 2022 Sep 6. No abstract available.
- Individual participant dataSharing planned: No
Related trials for Nephrolithiasis
Not yet recruiting
Automated Versus Manual Irrigation During Flexible Ureteroscopy
Renal Stone Disease
Not yet recruiting
Optimal Intrarenal Pressure During Flexible Ureteroscopy
Renal Stone Disease
RecruitingObservational study
Stone Clearance With Aspiration vs Other Technologies: a Real-world Evidence Study
Urolithiasis, Stones, Kidney
Not yet recruiting
Intertransverse Process Block Versus Erector Spinae Plane Block for Postoperative Analgesia After Percutaneous Nephrolithotomy
Kidney Stones, Urolithiasis, Hypocitraturia, Pain, Postoperative
Not yet recruiting
Comparison of Smart Pressure-Controlled Flexible Ureteroscopy and Flexible Suction Ureteral Access Sheath-Assisted Flexible Ureteroscopy for 2-3 cm Renal Stones
Kidney Stones
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Wilson Molina, MD principal investigator
Study Principal Investigator
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing ClearPetra Ureteral access sheath in people with Nephrolithiasis and Kidney Stone, run by University of Kansas Medical Center at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: stopped early, as of the sponsor's last update on 6 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study was stopped early (reason given: Change in guidelines). Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Stone Free Status between ClearPetra and traditional approach (time frame: 90 days). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06547632, which also lists 3 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 May 2026.