leave no stone unturned when it comes to the kidney, study says

even stones so small they aren't considered a problem should be removed, according to new research.

by dave yasvinski

published aug 15, 2022

3 minute read

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3 minute read

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leave no stone unturned when it comes to the kidney

around 12 per cent of canadian men — and six per cent of women — will develop a kidney stone at some point in their lives. getty

when it comes to taking care of kidney stones, a new study recommends also removing smaller objects that have not been considered problematic in the past. according to the research, published in the new england journal of medicine, surgeons who are tasked with removing such stones should not leave smaller objects behind because they increase the likelihood of a relapse. typically, these “secondary” stones, which are smaller than six millimetres in diameter — and not the primary target of removal — are merely monitored because they have a high rate of successful passage once they enter the ureter.

“before this study, the clinical views were pretty mixed on whether some of these stones should be treated,” said mathew sorensen, lead author of the study and a urologist at the university of washington school of medicine. “most clinicians would decide, based on the size of the stone, whether it hit the bar for treatment and if it did not, you would often ignore the little stones.”

kidney stones develop when deposits of certain minerals present in concentrated urine form tiny crystals that can vary in size from a grain of sand to a golf ball, according to the kidney foundation. the higher the temperature, the more people sweat and the more concentrated their urine becomes. while smaller stones generally pass through the urinary tract without an issue, larger ones can cause intense pain as they move from the kidney to the bladder. around 12 per cent of canadian men — and six per cent of women — will develop a kidney stone at some point in their lives, with the occurrence of one stone increasing the likelihood of another.

the team of researchers followed 75 patients who required attention at a series of medical facilities from 2015 to 2021. roughly half of this group had just their primary kidney stone treated; the other half had their primary and secondary stones removed. a relapse was defined as a patient needing to return to a facility for further medical treatment due to a recurrence or if a ct scan showed that secondary stones had grown.

they found that removing secondary stones at the same time as primary stones reduced the rate of relapse by 82 per cent. “the results of our trial support the removal of small asymptomatic renal stones at the time of surgery with a larger stone,” the paper concluded.

although treating smaller stones at same the time as larger ones would most likely increase the duration and expense of the procedure, the study points out that the time and money spent would likely be less than what would accompany a second trip to the emergency room. several participants in the study required multiple trips to the hospital before eventually receiving surgery for secondary stones.

the team said it hopes the results of their work will encourage colleagues to change their attitudes about secondary stones. more research is required to determine whether improved technology and decreasing costs justifies the removal of smaller stones alone.

“i think we have proven through this rigorous study that removal of the small asymptomatic stones is beneficial when feasible and in patients that are candidates to have all their stones treated in one procedure,” sorensen said. “leaving the stones behind risks trouble in the future.”

dave yasvinski is a writer with healthing.ca

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