Evaluation of Pain Before and After Removal of Non-obstructive Kidney Stones
Evaluation of Pain Before and After Removal of Non-obstructive Kidney Stones
Pain associated with renal stone disease is typically caused by an obstructing stone that
 obstructs the flow of urine, which results in renal collecting system dilatation.
 Non-obstructing renal calculi that do not cause renal collecting system dilatation are
 thought to be painless. The objective of this study is to prospectively determine if the
 removal of non-obstructing renal calculi can reduce or eliminate participant's pain and/or
 improve their quality of life.
Research Protocol

 -  Title of research project: Evaluation of pain before and after removal of
 non-obstructing renal calculi.

 -  Identification of Principal Investigator: Dr. Naeem Bhojani

 -  Multicentric study

 Rationale & background information Renal stone disease is a common condition representing a
 lifetime occurrence risk of 10% in men and 7% in women. Renal stone disease is a chronic
 condition with a high recurrence rate. Additionally, renal stone disease is associated with
 considerable morbidity including pain. Pain associated with renal stone disease is typically
 caused by an obstructing stone that obstructs the flow of urine, which results in renal
 collecting system dilatation. This increases the intraluminal pressure of the urinary
 collecting system and stretches nerve ending in the ureteral mucosa and renal capsule.
 Non-obstructing renal calculi that do not cause renal collecting system dilatation are
 thought to be painless. There is however, some evidence that non-obstructing renal calculi
 located within the renal calyces actually do cause pain. In a small (n=13) retrospective
 study, it was found that ureteroscopic removal of non-obstructing renal calyceal stones
 achieved complete or partial resolution of pain in all patients. The reason for this pain is
 unknown.

 Objective and hypothesis Objective To prospectively determine if the removal of
 non-obstructing renal calculi can reduce or eliminate participant's pain and/or improve their
 quality of life.

 Hypothesis We hypothesize that the removal of non-obstructing renal calculi will decrease or
 eliminate the participant's pain and will improve their quality of life.

 Design and methodology

 Study type:

 o Prospective multicentric study

 Study population:

 o Patients with non-obstructing renal calculi

 Inclusion criteria:

 -  Patients with renal colic and non-obstructing renal calculi. No stone greater than 10 mm
 in longest diameter

 -  All other causes of pain have been eliminated (by clinical judgment; if the cause of
 pain is in doubt: assessment by a family doctor or medical specialist will be obtained)

 -  Patients older than 18 years old

 -  Moderate to severe pain (> or = 5 on BPI pain scale: pain at its worst in the last
 24hrs)

 Exclusion criteria:

 -  Patient's with anatomic abnormalities (calyceal diverticulum)

 -  Ureteral calculi

 -  Nephrocalcinosis

 -  Renal Tubular Acidosis (RTA), medullary sponge kidney, sarcoidosis

 -  Hydronephrosis or hydrocalycosis

 -  Minimal pain (<5 on BPI pain scale: pain at its worst in the last 24 hrs)

 Methodology Our experimental plan begins with the identification of patients with
 non-obstructing kidney stones (< =10 mm (maximum length; measured via CT) with associated
 flank pain. Once all other causes of the pain have been eliminated, these patients will
 undergo ureteroscopy (URS) (standard treatment) to remove the offending kidney stones.

 URS will be performed in the standard fashion including the use of a guide wire +/- a
 ureteral access sheath. Laser lithotripsy will be performed if necessary and all fragments
 will be extracted with the use of a basket and will be sent for stone analysis. Once the
 offending stone(s) has/have been removed a double J ureteral stent will be placed if deemed
 necessary by the surgeon. The duration of the double J ureteral stent will be determined by
 the surgeon.

 All consented patients will undergo 3 evaluations preoperatively; The Brief Pain Inventory
 (BPI) (short version)[3], the Patient-Reported Outcomes Measurement Information System
 (PROMIS)-Pain inference/form 6b and the Wisconsin stone quality of life questionnaire
 (WSQOL). After removal of the renal calculi, these 3 forms will be completed by the
 participant at the time of stent removal or if no stent was placed, at 2 weeks
 post-operatively. Thereafter, the forms will be completed again at 6-8 weeks (+/- 1 week)
 after the initial procedure or 4 weeks (+/- 1 week) after the removal of their double J
 stent. Finally, the evaluations will be repeated at 12 weeks. Additionally, as with standard
 care at 6-8 weeks each patient will undergo post-operative imaging to determine if any renal
 calculi remain.

 Analysis of Data With regards to the BPI, if removal of the offending kidney stone(s) is the
 cause of the patient's pain we expect a decrease in pain ("pain at its worst in the last 24
 hours") of at least 20%. Patients included in this study should experience moderate to
 elevated flank pain in order to be able to detect a decrease of 20% of this pain
 post-intervention. This decrease will be considered clinically significant. In order to test
 our hypothesis, we plan to recruit a minimum of 53 patients to achieve a power of 80%.
 Patients will be their own control.

 Sample size calculation Sample size calculation was performed using GPower software, version
 3.1. Considering a baseline means Visual Analog Scale (VAS) of 7, we conservatively supposed
 a correlation of 0 and a standard deviation of 2.5. The standard deviation was estimated with
 the range (i.e. σ ≈ range/4), assuming the VAS to be normally distributed. Thus, a sample
 size of n = 53 is required to ensure at least 80% power to detect a clinically significant
 difference of 20 % (post-mean = 5.6), at a significance level of 5 %.

 Impact of the Proposed Research The results of this study will conceivably provide
 significant evidence on whether small non-obstructing renal calculi can cause flank pain.

 Ethical considerations

 -  All personal identifiers, such as patients' names, will be removed and replaced with a
 unique numerical code.

 -  Only the principal investigator and approved study staff will be able to identify the
 patients and have access to the study files.

 -  The consent will be kept in a locked office at the Research Center of the University of
 Montéral Hospital Center (CRCHUM).

 -  The data collected will be protected in files with a password on secure servers
 (computers).

 -  The data will be kept during a period of 10 years on secured computers with passwords by
 the principal investigator of this research project at the CRCHUM. After that, they will
 be destroyed.

 -  The combined results from this study may be used to prepare reports and summaries for
 scientific publications and presentations at scientific meetings. If they are, identity
 of the patients will remain confidential.
Inclusion Criteria:

 -  Patients with renal colic and non-obstructing renal calculi. No stone greater than 10
 mm in longest diameter

 -  All other causes of pain have been eliminated (by clinical judgment; if the cause of
 pain is in doubt: assessment by a family doctor or medical specialist will be
 obtained)

 -  Patients older than 18 years old

 -  Moderate to severe pain (> or = 5 on BPI pain scale: pain at its worst in the last
 24hrs)

 Exclusion Criteria:

 -  Patient's with anatomic abnormalities (calyceal diverticulum)

 -  Ureteral calculi

 -  Nephrocalcinosis

 -  RTA, medullary sponge kidney, sarcoidosis

 -  Hydronephrosis or hydrocalycosis

 -  Minimal pain (<5 on BPI pain scale: pain at its worst in the last 24 hrs)