This study will be a randomized controlled study comparing the use of two clinical management strategies in nephrostomy tube management following percutaneous nephrolithotomy (PCNL). The first strategy entails using contrast-enhanced ultrasound (CEUS) to evaluate the renal collecting system (1). This is a new imaging approach applying ultrasound machines with special software in combination with intraluminal ultrasound contrast agent (Lumason) injection, which is an FDA-approved ultrasound contrast agent (2). The second strategy is a nephrostomy tube capping trial combined with low dose non-contrast computed tomography (CT) scan, one of the most frequently utilized clinical management strategies currently used in clinical practice (3).
This is a multi-center, randomized controlled study comparing the use of CEUS to CT scan plus capping trial immediately following PCNL. A total recruitment target of 1,046 subjects is planned and participants will be randomized into one of the two study arms. 1. Contrast-enhanced ultrasound (CEUS) arm: On postoperative day 1 (unless not clinically indicated), each subject will undergo CEUS with an administration of Lumason via their pre-placed nephrostomy tube. 2. Non-contrast CT scan plus capping trial arm: On postoperative day 1 (unless not clinically indicated), subjects' pre-placed nephrostomy tube will be capped and they will undergo a low dose non-contrast abdominal CT scan. Subsequently, nephrostomy tubes will be managed based on the results from these studies by the treating surgeon. Screening data will be reviewed to determine subject eligibility. Subjects who meet all inclusion criteria and none of the exclusion criteria will be entered into the study. The following investigational regimen will be used only in the CEUS arm: Experimental Investigation: Lumason at a 2 mL single dose, repeatable once at the time of imaging as needed. Subjects will be exposed to the randomization schema for 1 day during which they will undergo one of the two diagnostic imaging pathways. After that imaging study is complete, clinical care will proceed as per norm. Clinical and imaging data will be prospectively collected from the time of initial presentation until 6 months after surgery. The total duration of the study is expected to be 5 years to reach target accrual. Therefore, the investigators anticipate that the total duration of this study will be 4 years and 6 months for patient recruitment with the final 6 months used for collecting follow up data.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
DIAGNOSTIC
Masking
DOUBLE
In subjects randomized into the CEUS arm, 2 mL of Lumason will be injected as a single dose via a nephrostomy tube at the time of postoperative renal ultrasound, following by 5 mL of normal saline flush. Subjects will be given up to one additional dose injected in the same fashion as indicated during the imaging study to confirm opacification of the ureter.
The CT scan performed in this study arm is regularly performed to evaluate the kidney and look for residual stones after surgery both at UCSF and around the world. It does not require contrast injection, so risks from contrast allergy or any injection are absent. A low dose protocol will be used, and therefore, subjects will be exposed to a very small amount of ionizing radiation as low as 1-2 mSv if randomized into this arm.
Radiation exposure dose
For radiation exposure dose measurement in this study, the investigators will use dose metrics obtained from the Digital Imaging and Communications within the scanners or Picture Arching and Communication system (PACS).
Time frame: 6 months following surgery
Rate of adverse clinical events
Defined as postoperative complications and any unplanned surgery related to the patient's kidney stone
Time frame: 6 months following surgery
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Subjects who are randomized into this study arm will undergo both nephrostomy tube capping and a low dose non-contrast CT scan on the first day after surgery. Successfully passing a capping trial is defined as the absence of fever, worsened flank pain, and leakage around the nephrostomy tube within 4 hours after capping the tube.