Feasibility of Radiation-Free Percutaneus Nephrolithotomy for Kidney Stones

Active, not recruiting

• Conditions: Kidney Stones

• Registration Number: NCT06922006
• Lead Sponsor: University of California, San Diego

Brief Summary

The goal of this observational study is to investigate the feasibility of ultrasound-guided percutaneus nephrolithotomy in patients with kidney stones. The main question's it aims to answer are:

Does the use of ultrasound in percutaneus nephrolithotomy affect stone free rates, defined by no stone or stone \<2mm, on follow up visit?

Does the use of ultrasound in percutaneus nephrolithotomy affect complication rates, categorized by Clavien system?

Researchers will compare ultrasound-guided percutaneus nephrolithotomy to traditional nephrolithotomy using fluoroscopy to see if outcomes differ.

Participants will be chosen for any of the above interventions at surgeon's discretion.

Detailed Description

Percutaneous nephrolithotomy (PCNL) is a minimally invasive procedure for removal of kidney stones that has traditionally been done using fluoroscopy for guidance. This study aims to explore if PCNL can be done safely using ultrasound as a replacement for fluoroscopy to decrease radiation exposure.

This study is a prospective cohort comparing subjects that undergoes radiation free and non-radiation free PCNLs performed by a single surgeon at UCSD Health. All cases are evaluated for ultrasound feasibility, and some have to be converted to fluoroscopy at surgeon's discretion. Information about the risks of the procedure including bleeding, infection, incomplete stone removal and injury to the kidney is given to each participant. All surgeries are performed by an experienced urologist with a history of successful ultrasonography interpretation and fluoroscopy is always accessible in the OR in case ultrasonography would not offer good enough imaging quality for the procedure to be completed in a safe and successful manner. The study does not affect the choice of imaging modality used for individual procedures but only looks at characteristics and outcomes of already performed surgeries.

Subjects are selected from the schedule in Epic and divided into three groups, radiation free PCNLs, converted cases and planned PCNLs with fluoroscopy based on information provided in the operative note from each procedure. All subjects that appear on the schedule are included in this study. Data is collected from a US electronic medical record system (Epic), using an online database tool, RedCap. The data consists of 15 cases that have undergone radiation free PCNL, 15 cases that were converted to fluoroscopy, 32 cases that were planned and performed with fluoroscopy. 5 operations had to be aborted. Data is divided into patient demographics (age, gender, ethnicity, BMI, past medical history, anticoagulants), pre-operative data (ASA class, pre-op tubes, laterality, total stone burden, number of stones, stone location, pre-op urine culture, reason for radiation or radiation-free procedure), operative data (imaging modality, access location, number of access attempts, tract dilation size, end of tube case, estimated blood loss, end of case residual stones, total time in operating room (OR), total time under fluoroscopy) and postoperative data (admissions, hospital length of stay, inpatient course, discharge antibiotics, 30 day complications, post-op imaging, post-op stone size, need for additional procedure, post-op creatinine levels and GFR).

Study Timeline

• Study Start: 2024-03-26
• Study First Submitted: 2025-03-27
• Status Verified: 2025-04
• Study First Submitted QC: 2025-04-08
• Last Update Submitted: 2025-04-08
• Study First Posted: 2025-04-10
• Last Update Posted: 2025-04-10
• Primary Completion: 2025-05
• Study Completion: 2025-06

Recruitment & Eligibility

• Status: ACTIVE_NOT_RECRUITING
• Sex: All
• Target Recruitment: 67

Inclusion Criteria

Scheduled percutaneus nephrolithotomy by Dr. Roger Sur between 2022 and 2025 at UCSD Hillcrest.

Exclusion Criteria

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Stone free rates	4-6 weeks after surgery.	The rate of patients with no stone, or \<2mm stone on follow up visit.

Secondary Outcome Measures

Name	Time	Method
Complication rates	From date of surgery to 30 days post surgery.	Rate of complications defined by Clavien stage 1-5.
ED visits	From surgery to 30 days after surgery.	Rate of patients that had to visit the emergency departent after the surgery.
Re-admission rates	From surgery to 30 days after surgery.	Rate of patients that had to be re-admitted after the surgery.
Required additional procedure after PCNL.	From surgery to 30 days after surgery.	Rate of patients that had to be planned for additional procedure after the surgery.
End of case residual stone prescense.	At the end of surgery (In the operating room).	Rate of patients that had a residual stone visible after the procedure.
Post-operative stone size	4-6 weeks after surgery.	Size of kidney stone on follow up visit after the surgery.
Hospital length of stay.	From surgery to 4-6 weeks after surgey.	Amount of days spent in hospital post-operatively.
Post-operative outpatient creatinine levels	From 30 days after surgery to next available creatinine level available in medical records.	Creatinine levels.
Post-operative glomerulal filtration rate (GFR)	From 30 days after surgery to next available creatinine level available in medical records.	Glomerulal filtration rate (GFR) as an indicator of kidney function post-operatively.
Estimated blood loss	From the time of incision to the time of closure.	Amount of blood loss the patient had during the surgery.
Total OR time	From when the patient enters the operating room until the patient leaves the operating room.	Time spent in the operating room
Incision to close time	From the first incision until closure of the last incision.	Time spent operating.

Trial Locations

Locations (1)

University of California San Diego, Hillcrest; 🇺🇸 San Diego, California, United States