Feasibility of Radiation-Free Percutaneus Nephrolithotomy for Kidney Stones (PCNL)

Is Radiation Free Percutaneous Nephrolithotomy (PCNL) Feasible: A Prospective Trial

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.

Study Overview

• Status: Active, not recruiting
• Conditions: Kidney Stones
• Intervention / Treatment: Procedure: Percutaneus nephrolithotomy (PCNL)

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 Type: Observational
• Enrollment (Estimated): 67

Contacts and Locations

Study Locations

• United States
  • California
    • San Diego, California, United States, 92103
      • University of California San Diego, Hillcrest

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

General population with kidney stones larger than 20mm.

Description

Inclusion Criteria:

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

Exclusion Criteria:

-

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Radiation-free PCNL; Cases that were done using ultrasound as the only imaging modality during the entire procedure.	Procedure: Percutaneus nephrolithotomy (PCNL); Percutaneus nephrolithotomy (PCNL) for removal of large kidney stones
Fluoroscopy-guided PCNL; Traditional PCNL's that were planned and performed with fluoroscopy.	Procedure: Percutaneus nephrolithotomy (PCNL); Percutaneus nephrolithotomy (PCNL) for removal of large kidney stones
Converted from radiation-free to fluoroscopy-guided PCNL; Cases that were planned to be done with ultrasound but that ended up having to use fluoroscopy.	Procedure: Percutaneus nephrolithotomy (PCNL); Percutaneus nephrolithotomy (PCNL) for removal of large kidney stones

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Stone free rates	The rate of patients with no stone, or <2mm stone on follow up visit.	4-6 weeks after surgery.

Secondary Outcome Measures

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

Collaborators and Investigators

• Sponsor: University of California, San Diego
• Investigators: Principal Investigator: Roger L Sur, MD, University of California, San Diego

Study record dates

Study Major Dates

• Study Start (Actual): March 26, 2024
• Primary Completion (Estimated): May 1, 2025
• Study Completion (Estimated): June 1, 2025

Study Registration Dates

• First Submitted: March 27, 2025
• First Submitted That Met QC Criteria: April 8, 2025
• First Posted (Actual): April 10, 2025

Study Record Updates

• Last Update Posted (Actual): April 10, 2025
• Last Update Submitted That Met QC Criteria: April 8, 2025
• Last Verified: April 1, 2025

More Information

Terms related to this study

• Keywords: PCNL
• Additional Relevant MeSH Terms: Urogenital Diseases; Male Urogenital Diseases; Calculi; Pathological Conditions, Anatomical; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urolithiasis; Urinary Calculi; Kidney Calculi; Nephrolithiasis
• Other Study ID Numbers: IRB#180946

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No