Ultrasound can be used to move, reposition, or break up kidney stones, all while the patient is awake, a new study finds.
The new technique, which combines the use of two ultrasound technologies, may offer an option to move kidney stones out of the ureter with minimal pain and no anesthesia, the researchers reported.
In the procedure, the physician uses a handheld transducer placed on the skin to direct ultrasound waves toward the stone.
The ultrasound can then be used to move and reposition the stones to promote their passage, a process called ultrasound propulsion, or to break up the stone, a technique called burst wave lithotripsy (BWL).
“It’s nearly painless, and you can do it while the patient is awake, and without sedation, which is critical.”
The research team hopes that, with this new technology, the procedure of moving or breaking up the stones could eventually be performed in a clinic or emergency room setting, Hall said.
One in 11 Americans will have a urinary stone over the course of their lifetime. The incidence appears to be increasing, according to a previous study that looked at the same technology. Up to 50 percent of patients with a stone event will recur within five years.
Hall and colleagues evaluated the new technique to meet the need for a way to treat stones without surgery. They designed the study to test the feasibility of using the ultrasonic propulsion or BWL to break up stones in awake, unanesthetized patients, Hall said.
Burst wave lithotripsy fragmented the stones in seven of the cases. At a two-week follow up, 18 of 21 patients (86 percent) whose stones were located lower in the ureter, closer to the bladder, had passed their stones. In this group, the average time to stone passage was about four days, according to the study, which reported that one of these patients felt “immediate relief” when the stone was dislodged from the ureter.
The next step for the researchers is to perform a clinical trial with a control group, which wouldn’t receive either BWL bursts or ultrasound propulsion, to evaluate the degree to which this new technology potentially aids stone passage, Hall said.
Development of this technology first started five years ago, when NASA funded a study to see if kidney stones could be moved or broken up, without anesthesia, on long space flights such as the Mars missions. The technology has worked so well that NASA has downgraded kidney stones as a key concern.
“We now have a potential solution for that problem,” Hall said.
Other University of Washington Medicine trials have looked at breaking apart kidney stones inside the kidneys. This was the first trial to look at moving the stones or breaking them apart while inside the ureter with BWL, Hall said.
NASA, the National Institutes of Health, and the National Space Biomedical Research Institute supported the work.
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