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Renal StonesNCT07071831

RETRO Study (RETrograde Renal Access Outcomes)

An observational study of Renal Stones, run by University of Kansas Medical Center at 2 sites in United States.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial summary

The goal of this observational study is to learn about the benefit of using RetroPerc® in obtaining renal access for percutaneous nephrolithotomy. The device is already used in routine clinical practice by urologists around the country. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Renal Stones
What is being tested?
RetroPerc®
Type of treatment
Medical device
How many people
150 participants
Where
2 sitesUnited States
Study dates
6 Dec 2024to Dec 2027
Phase
Observational
Are there results?
Not yet: the study is under way

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
  • No healthy volunteers
  • Adult, Older adult

Study population: Participants undergoing percutaneous nephrolithotomy for treatment of their renal stone (s) total linear sum of 1.5 to 3cm cm in maximum dimension.

Who may be able to join

  • Renal stone or total linear sum of 1.5-3cm cm in maximum dimension (largest diameter in axial or coronal)--- multiple stones should be summed to determine stone size.
  • Age >=18 years of age
  • Gender: both men and women included.
  • Ethnic background: all ethnicities will be included in the study population and the specific ethnic diversity present in the study population will reflect the geographic distributions of the participating institutions.
  • Plan for PCNL in the supine position

Who cannot join

  • Active pregnancy
  • BMI >45
  • Severe Hydronephrosis - renal pelvis diameter > 20mm
  • Flank window < 4 cm are ineligible for puncture
  • Previous ipsilateral PCNL
  • Currently with "useful" nephrostomy tube on ipsilateral side
Show all 24Show fewer
  • Uncorrectable coagulopathies
  • Untreated urinary tract infection
  • Subjects with significant morbidities such as American Society of Anesthesiologists (ASA) score ≥ 4, severe spinal cord injuries, severe cardiopulmonary insufficiency, uncontrolled diabetes, neurological disorders, bedbound, anticipated life expectancy less than 5 years, or any other comorbidity, that in the opinion of the principal investigator could represent an increased peri-operative risk for the subject;
  • Ipsilateral partial nephrectomy
  • History of ipsilateral ureteral reimplantation or ureteral reconstruction;
  • History of Simple or radical prostatectomy
  • History of cystectomy
  • History of calyceal diverticula stone;
  • History of renal donation or transplant;
  • Any other previous pelvic surgical treatment that could put the subject at greater procedural complication risk or technical difficulty;
  • Ureteral ipsilateral stricture, untreated;
  • Ureteral stricture, untreated (not to include "tight" ureter);
  • Any other bladder, ureteral or kidney congenital genitourinary abnormalities (e.g. Horseshoe kidney, ipsilateral duplicated or partially duplicated collecting system, ipsilateral ectopic kidney, cross-fused ectopia, bifid renal pelvis with no horizontally directed calyces, solitary kidney, etc.) preventing the ability to direct a puncture laterally or render the subject stone free;
  • Have participated in any other clinical trial within the last 3 months, and/or plans to participate in any other investigational or invasive clinical trial during this study;
  • If female, breast-feeding, or if childbearing age, is not using contraception between screening and 90 days post-op;
  • Subject has current or recent history of substance abuse (e.g. recreational drugs, narcotics, or alcohol) requiring intervention;
  • Is a prisoner or ward of the state;
  • Is unable to meet the treatment and follow up protocol requirements.

Trial locations and contacts

2 sites in 1 country. Contact the study team or a site near you to ask about taking part.

Research Program Manager contact

913-588-8721

jledesma2@kumc.edu

United States2 sites, 2 recruiting

  • University of Kansas Medical Center

    Kansas City, Kansas, 66105

    Research Program Manager, 913-588-8721, jledesma2@kumc.edu

    Bristol Whiles, MD

    Recruiting

  • University of South Florida

    Tampa, Florida, 33606

    Renya Maku, 813-821-8035, rmaku@tgh.org

    David Hernandez, MD

    Recruiting

Other trials in United States

About this study

Official title: RetroPerc®-A Prospective, Multi-institutional Trial of Efficacy of the RetroPerc Device

The goal of this observational study is to learn about the benefit of using RetroPerc® in obtaining renal access for percutaneous nephrolithotomy. The device is already used in routine clinical practice by urologists around the country.

Participants who are already scheduled to undergo percutaneous nephrolithotomy as part of their regular care will be asked to participate.

Read the detailed description

Retrograde nephrostomy access is well established as a safe method for nephrostomy creation and thus this study aims to perform a standard of care study. The device is already available, on the shelf, and used in routine clinical care. However, the study aims to take a closer look in a prospective fashion at this access technique to better understand specific variables that are not available on retrospective review of cases that have already undergone PCNL with this technique.

Conditions
Renal Stones
Being tested
RetroPerc®
Keywords
kidney stones
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.

  • RetroPerc®Device

    The RetroPerc® will be used to obtain renal access.

Study groups in NCT07071831
Study groupRoleWhat they receive
Percutaneous NephrolithotomyParticipants with a single renal stone or total sum of 1.5 to 3 cm in maximum dimension of multiple stones undergoing percutaneous nephrolithotomy as part of their routine medical care using the RetroPerc® system to obtain renal access.
Receives: Device: RetroPerc®

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Proportion of successful renal access per access attempts

    The proportion of successful renal access was compared to the renal access attempts (e.g. 100 success attempts/110 attempts).

    Measured: Procedure

Secondary outcomes (4)

  1. Location of Renal Access

    The location of renal access was determined during the procedure. Location of access was defined as upper pole, mid pole, and lower pole.

    Measured: Procedure

  2. Time to gain renal access

    The time to gain renal access was defined as the time the ureteroscope enters the kidney to the time when the nephroscope enters the kidney

    Measured: Procedure

  3. Total Procedure Time

    The total procedure time is defined as the time when the cyso/urethroscope enters the urethra to the time time of skin closure.

    Measured: Procedure

  4. Length of Post-Operative Hospital Stay

    The post-operative hospital length of stay range is defined from 0 days to longer than 5 days.

    Measured: Day 0 to 3 Months Post-Operative

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted17 Jul 2025
  2. Study start6 Dec 2024
  3. Primary completionApr 2027 (estimated)
  4. Study completionDec 2027 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Observational
Observational model
Cohort
Time perspective
Prospective
Enrolment
150 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07071831
Sponsor's protocol ID
STUDY00160854
Status last verified
May 2026
First submitted
8 Jul 2025
Last updated
4 May 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Yes: De-identified participant data collected during the study

Publications

  • Lee CL, Anderson JK, Monga M. Residency training in percutaneous renal access: does it affect urological practice? J Urol. 2004 Feb;171(2 Pt 1):592-5. doi: 10.1097/01.ju.0000104849.25168.6d.

    PubMed 14713766

  • Alotaibi KM. Retrograde nephrostomy access for percutaneous nephrolithotomy: a simple and safe technique. Urolithiasis. 2020 Apr;48(2):175-181. doi: 10.1007/s00240-019-01135-z. Epub 2019 Apr 29.

    PubMed 31037404

  • Kaler KS, Parkhomenko E, Lin CY, Valley ZA, Kim WK, Okhunov Z, Patel RM, Landman J. A New Twist on an Old Technique: Lawson Retrograde Endoscopic-Guided Nephrostomy Access for Percutaneous Nephrolithotomy in Prone Split-Leg Position. J Endourol Case Rep. 2018 Nov 29;4(1):190-194. doi: 10.1089/cren.2018.0073. eCollection 2018.

    PubMed 30515460

  • Wynberg JB, Paik LJ, Odom BD, Kruger M, Atalla CS. Body mass index predicts outcome of ureteroscopy-assisted retrograde nephrostomy for percutaneous nephrolithotomy. J Endourol. 2014 Sep;28(9):1071-7. doi: 10.1089/end.2014.0204. Epub 2014 Jun 12.

    PubMed 24779944

  • Sivalingam S, Al-Essawi T, Hosking D. Percutaneous nephrolithotomy with retrograde nephrostomy access: a forgotten technique revisited. J Urol. 2013 May;189(5):1753-6. doi: 10.1016/j.juro.2012.11.169. Epub 2012 Dec 3.

    PubMed 23219545

  • Al-Otaibi KM. Retrograde upper-pole calyceal access for percutaneous nephrolithotripsy of stones in the lower-pole calyx. Arab J Urol. 2012 Dec;10(4):353-7. doi: 10.1016/j.aju.2012.08.002. Epub 2012 Sep 23.

    PubMed 26558049

  • Kawahara T, Ito H, Terao H, Kato Y, Uemura H, Kubota Y, Matsuzaki J. Effectiveness of ureteroscopy-assisted retrograde nephrostomy (UARN) for percutaneous nephrolithotomy (PCNL). PLoS One. 2012;7(12):e52149. doi: 10.1371/journal.pone.0052149. Epub 2012 Dec 14.

    PubMed 23251698

  • Smiths Textbook of Endourology. 2007, BC Decker Publ. Ch. 15, Dr. D. Hosking - "Retrograde Nephrostomy", Pg. 117.

  • Mokulis JA, Peretsman SJ. Retrograde percutaneous nephrolithotomy using the Lawson technique for management of complex nephrolithiasis. J Endourol. 1997 Apr;11(2):125-30. doi: 10.1089/end.1997.11.125.

    PubMed 9107586

  • Wong HY, Hinson JL, Griffith DP. Retrograde nephrostomy: advantages, disadvantages, and the learning curve. J Endourol. 1995 Dec;9(6):461-3. doi: 10.1089/end.1995.9.461.

    PubMed 8775075

  • Morrisseau PM, Trotter SJ. Retrograde percutaneous nephrolithotomy: urological treatment of a urological problem. J Urol. 1988 Jun;139(6):1163-5. doi: 10.1016/s0022-5347(17)42847-3.

    PubMed 3373578

  • Spirnak JP, Resnick MI. Retrograde percutaneous stone removal using modified Lawson technique. Urology. 1987 Dec;30(6):551-3. doi: 10.1016/0090-4295(87)90434-1.

    PubMed 3686771

  • Hunter PT, Hawkins IF, Finlayson B, Nanni G, Senior D. Hawkins-Hunter retrograde transcutaneous nephrostomy: a new technique. Urology. 1983 Dec;22(6):583-7. doi: 10.1016/0090-4295(83)90300-x.

    PubMed 6649222

  • Lawson RK, Murphy JB, Taylor AJ, Jacobs SC. Retrograde method for percutaneous access to kidney. Urology. 1983 Dec;22(6):580-2. doi: 10.1016/0090-4295(83)90299-6.

    PubMed 6649221

Questions about this trial

What is this clinical trial studying?

An observational study of Renal Stones, run by University of Kansas Medical Center at 2 sites 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 5 inclusion and 24 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: looking for participants now, as of the sponsor's last update on 4 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 2 sites 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?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Research Program Manager (913-588-8721, jledesma2@kumc.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Proportion of successful renal access per access attempts (time frame: Procedure). 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 NCT07071831, which also lists 14 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 4 May 2026.

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