An observational study in Renal Stones, sponsored by University of Kansas Medical Center. Recruiting at 2 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-05-04.
Sponsored by University of Kansas Medical Center · Observational
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.
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.
324 studies on the registry are indexed under Nephrolithiasis; 90 are open to participants now.
This study's planned enrollment of 150 is above the median of 100 across 57 observational studies indexed under Nephrolithiasis.
Browse Nephrolithiasis studies →University of Kansas Medical Center is the lead sponsor of 492 studies on the registry; 110 are open to participants now.
Of its 38 completed or terminated interventional studies of FDA-regulated products, 24 (63%) have results posted.
Counted across the registry records on this site, refreshed daily.
Participants undergoing percutaneous nephrolithotomy for treatment of their renal stone (s) total linear sum of 1.5 to 3cm cm in maximum dimension.
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:
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.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Life expectancy
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants 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.
Device: RetroPerc®
The RetroPerc® will be used to obtain renal access.
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).
Time frame: Procedure
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.
Time frame: Procedure
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
Time frame: Procedure
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.
Time frame: Procedure
Length of Post-Operative Hospital Stay
The post-operative hospital length of stay range is defined from 0 days to longer than 5 days.
Time frame: Day 0 to 3 Months Post-Operative
Plan to share: Yes — De-identified participant data collected during the study
Supporting information: Statistical analysis plan, Clinical study report
Time frame: Following end of study
Access criteria: Data may be requested by participating study investigators. The participating sites must have a data use agreement in place before requesting access to the data.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
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