Presurgical management will follow the standard of care and patients with active urinary
tract infections will be treated prior to kidney stone surgery. After the informed
consent process, the subject will be asked to complete the Wisconsin Stone Quality of
Life Index (WISQOL), an externally validated and internally consistent questionnaire
designed specifically for kidney stones patients. All patients should receive a
computerized tomography (CT) scan prior to their procedure as standard of care for
assessment of stone burden and access planning. This preoperative imaging will be
assessed and scored using the standardized STONE scoring system, which has been validated
for predicting treatment success and perioperative complications following PCNL.
Prior to their procedure patients will be randomized to receive one of the two
interventions outlined above, only study subjects will be blinded to the randomization.
Randomization will be conducted centrally for each site to ensure balance of PCNL and
mini-PCNL using the CCF-Redcap randomization module to ensure proper randomization
between sites. Randomization can occur at any time after enrollment prior to surgery.
Study subjects will be selected from a patient pool where PCNL or mini-PCNL would be
considered equally viable alternative Standard of Care procedures for treatment of kidney
stone disease, with neither procedure presenting any benefit over the other. The
randomization of procedure for this pool of study subjects was to guarantee that an equal
number of both procedures were performed in the trial throughout all centers.
Patients choosing to participate in this research study will not be informed of which
procedure they received to minimize any bias regarding postoperative pain and quality of
life scores. No changes to the disclosure process will be made for any other variations
or complications during their procedure outside of the research study interventions. Due
to the time between the initial surgical procedure and postoperative follow-up visit
there is a risk of unintentional unblinding by other providers involved with the care of
study patients and access to their medical records. As such patients will be asked at the
time of their follow-up visit if they remained blinded to their procedure type. Whenever
possible patients should remain blinded but unblinding is not an exclusion criterion as
the primary endpoint, change in hemoglobin, should not be affected by this knowledge.
A pre-operative complete blood count and basic metabolic panel will be obtained. Two
endoscopic stone procedure types will be investigated in this study. The first, a
standard percutaneous nephrolithotomy (sPCNL)- performed using a 30 Fr access sheath
following balloon dilation. The second, a mini percutaneous nephrolithotomy (mPCNL)-
performed using an 18 Fr access sheath following either balloon dilation or dilation
using a single step metal dilator. Both procedures will be performed under general
anesthesia with the patient in prone position. Access technique (triangulation method,
ultrasound guided, or endoscopically guided) will be at the discretion of the attending
surgeon. Stone lithotripter type (pneumatic, ultrasonic, or laser) and retrieval method
(basket, forceps) will similarly be at the discretion of the urologist. Placement of
ureteral stents will be left up to the discretion of the surgeon. Placement of
nephrostomy tubes will be recorded as a protocol deviation and the indication for
placement recorded. Whenever possible a single access tract will be used for the
procedure and if multiple access sites are required it will be recorded as a protocol
deviation. Following completion of the procedure and closure of the access tract,
pressure will be applied to the surgical site for one minute. Patients with plans for a
staged bilateral PCNL should only be enrolled for their first operation and should
complete the quality-of-life questionnaire and imaging requirements described below prior
to their second procedure.
Renal pelvis pressure monitoring is not part of the standard of care and is included as
an outcome for research purposes only. There is no additional risk to the patient when
monitoring this pressure and patients will be informed of this during the informed
consent process.
Using a flexible cystoscope, a 5 Fr open-ended ureteral catheter will be positioned in
the ureteropelvic junction for recording renal pelvis pressures. Following placement, the
catheter will be secured and attached to arterial line pressure transducer positioned at
the level of the kidney and connected to an invasive blood pressure (IBP) port. The
arterial line pressure transducer will be fixed to IV pole at the level of the kidney and
adjusted during the case if the patient bed is repositioned during the case. Transducer
tubing should be flushed with normal saline to remove any air and pressure should be
zeroed without any pressure being applied to the surgical site. Pressure monitoring and
zeroing should be established after obtaining access but prior to active stone
fragmentation or extraction and continue until closure of the access tract.
Continuous data monitoring and recording will be achieved via attaching the IBP port
either on a portable vital signs monitor or the main anesthesia monitoring system. Data
points should be recorded continuously whenever possible. Data will be either extracted
manually from the portable monitor or automatically through the anesthesia monitoring
system. Analysis of these data points to determine the mean RPP, time above >30mmHg, and
maximum RPP can be conducted at the individual sites and included as part of their data
set transfer or deidentified data sets can be sent to CCF for analysis of those
endpoints.
Post-operatively, patients will be admitted to the hospital and monitored per usual
clinical procedure. A complete blood count will be obtained on postoperative day 0,
preferably in recovery, and on postoperative day 1. A basic metabolic panel will also be
obtained prior to discharge. Further laboratory tests will be dictated by the patients'
clinical status and length of stay. If patient length of stay exceeds one day the final
complete blood count prior to discharge will also be recorded.
Along with their standard postoperative day 1 labs, an additional red topped tube
(4-10ml) for IL-6 and procalcitonin will also be collected. This sample will need to be
processed with several hours of collection using a centrifuge and the serum aliquots
placed in cryovials prior to freezing. Individual research sites will be responsible for
the lab draw, centrifuge process, freezing, and shipping of IL-6 and procalcitonin serum
samples. These may be stored on site and shipped in bulk periodically or upon conclusion
of patient enrollment per the preference of the study coordinator at each site. All these
samples will be analyzed in bulk at the conclusion of the recruitment period.
Since higher irrigating pressures during PCNL have been linked to higher rates of the
systemic inflammatory response (SIRS) this will also be included as a secondary endpoint.
The criteria for SIRS will be defined as any two of the following conditions: heart rate
>90 beats per minute, respiratory rate >20 respirations per minute, serum white blood
cell count greater than 12,000/high power field or less than 4,000/high power field and
temperature >38.0 ⁰C or <36.0 ⁰C.
Postoperative complications will be classified using the Clavien-Dindo system which has
been modified for use following percutaneous nephrolithotomy. Standard of care procedures
will be followed for patients requiring postoperative blood transfusions. Postoperative
pain management will be left up to the discretion of the attending surgeon. The patient
will be discharged from the hospital per the usual clinical protocols with a planned
clinic visit between 4 and 6 weeks after surgery. In the interval following surgery
readmissions, ED visits, and reoperations for study patients should be recorded.
As part of the standard of care for PCNL patients, both a renal ultrasound and a kidney,
ureter, and bladder x-ray study obtained between 4 and 6 weeks postoperatively. Imaging
will be reviewed by a blinded radiologist for assessment of stone free rate, defined as
no visible stone fragments on either imaging set. Any discrepancies between ultrasound
and x-ray modalities will be resolved with a follow-up CT scan.
If a patient receives a postoperative CT scan for another indication, this scan will take
the place of the KUB and U/S for determining stone free rate. Additional data points such
as parenchymal thickness at target calyx will for also be assessed for swelling/fluid
accumulation.
The WISQL questionnaire, the same administered following initial consent, will be given
at the 4-6 week follow-up visit to track any differences in quality of life between the
two procedures. The WISQOL questionnaire specifically asks for the patients to provide
answer statements that reflect their quality of life over the past four weeks. For the
purposes of the second instance of the questionnaire, study subjects will be instructed
to answer with respect to their symptoms since their procedure, to encompass patients who
may have their follow-up visit scheduled more than four weeks from their procedure date.
The timeline for study subject participation and the required tests is presented below.
Procedures Preoperative POD0 POD1 Weeks 4-6 Informed consent X CT Scan X WISQOL Survey X
X CBC X X X BMP or CMP X X Randomization X Intraoperative RPP X Serum sample (IL-6 and
PCT) X KUB and renal U/S X