NCT07071831 · University of Kansas Medical Center
RETRO Study (RETrograde Renal Access Outcomes)
What this study is about
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.
View original scientific description
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.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 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
Exclusion criteria
- Active pregnancy
- 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
- 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.
Where
- Tampa, Florida
- Kansas City, Kansas
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced May 4, 2026 · Source of record for eligibility and locations