RETRO Study (RETrograde Renal Access Outcomes)

Recruiting

• Conditions: Renal Stones

• Registration Number: NCT07071831
• Lead Sponsor: University of Kansas Medical Center

Brief 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.

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

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.

Study Timeline

• Study Start: 2024-12-06
• Status Verified: 2025-07
• Study First Submitted: 2025-07-08
• Study First Submitted QC: 2025-07-08
• Last Update Submitted: 2025-07-08
• Study First Posted: 2025-07-17
• Last Update Posted: 2025-07-17
• Primary Completion: 2026-04
• Study Completion: 2026-12-01

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 150

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
• 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
• 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.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Proportion of successful renal access per access attempts	Procedure	The proportion of successful renal access was compared to the renal access attempts (e.g. 100 success attempts/110 attempts).

Secondary Outcome Measures

Name	Time	Method
Location of Renal Access	Procedure	The location of renal access was determined during the procedure. Location of access was defined as upper pole, mid pole, and lower pole.
Time to gain renal access	Procedure	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
Length of Post-Operative Hospital Stay	Day 0 to 3 Months Post-Operative	The post-operative hospital length of stay range is defined from 0 days to longer than 5 days.
Total Procedure Time	Procedure	The total procedure time is defined as the time when the cyso/urethroscope enters the urethra to the time time of skin closure.

Trial Locations

Locations (1)

University of Kansas Medical Center; 🇺🇸 Kansas City, Kansas, United States