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Contrary to the recommendations followed so far, a new American trial evokes the benefits of removing asymptomatic stones of less than 6 mm to reduce recurrences over time. And avoid going to the emergency room.
Should the smallest asymptomatic kidney stones (less than or equal to 6 mm) be eliminated or not for patient comfort? The question remained unresolved among urologists, treated on a case-by-case basis. But a new American randomized trial, published in August in The New England Journal of Medicine states that approximately half of small kidney stones left in place by the time larger stones are removed would cause further symptomatic events within 5 years of surgery. Their withdrawal, on the contrary, would reduce the risk and, in the case of a recurrence, would lengthen the time between two attacks.
Fewer recurrences in treated patients.
To achieve this result, the team of scientists from the Washington School of Medicine conducted a randomized trial conducted between 2015 and 2020, on 73 patients suffering from urolithiasis. During endoscopic removal of ureteral or contralateral kidney stones, remaining small asymptomatic stones were removed in 38 patients (treatment group) and were not removed in 35 patients (control group). After a follow-up of approximately 5 years during which all the patients had received the same prevention instructions, the risks of recurrence measured show a significant advantage for patients whose small asymptomatic stones have been removed. In fact, only 16% of the treated group experienced a recurrence within 5 years, compared to 63% in the control group. In addition, in the event of recurrence, this occurred on average after a 36% longer period of time in the treated patients compared to the control group.
A slightly longer procedure
After 5 years of study, the authors are therefore in favor of the removal of small kidney stones, when an endoscopic operation for large urethral or kidney stones is already planned.
The risks during the operation were also mentioned: the study indicates that the patients treated were only operated on average 25 minutes longer than the others to remove these asymptomatic stones, without an increase in the risk of recourse to the emergency room within 2 weeks post-op. However, results need to be completed in a larger study.
For Michael Peyromaure, head of the urology department at Cochin Hospital in Paris, the trial is not without interest:
“This trial is interesting because it tries to answer (even if the numbers are insufficient) a question that every urologist asks very frequently: when a patient is admitted for the surgical removal of a symptomatic urinary calculus (i.e. say, responsible for pain), should we take advantage of the same intervention to also treat the other small stones located in the kidney and which are not symptomatic? In this comparative study, the authors show that if all stones are treated at the same time, patients will have less risk of being rehospitalized, in particular for renal colic, in the following four years. They nevertheless raise several drawbacks: the increase in operating time, surgical complications, and the possible “overtreatment” of small stones, a large part of which would never have caused complications.“
Renal colic: what precautions to avoid recurrences?
Remember, however, that to limit the risk of recurrence of episodes of renal colic and the formation of new stones, prevention is based on 3 axes:
- Good daily hydration, i.e. 2 liters of water minimum to drink in 24 hours to distribute throughout the day.
- A balanced diet, standardized in calcium (800 mg/d), salt (9 g/d) and animal protein (< 1.2 g/kg/d).
- An annual follow-up by ultrasound as well as a blood and urine metabolic assessment is also to be carried out for people who experience this problem.