A new ultrasonic technique developed for emergency kidney stone treatments on Mars may offer an option to move kidney stones out of the ureter with minimal pain and no anaesthesia, according to a new feasibility study published in The Journal of Urology.
In the procedure, the physician uses a handheld transducer placed on the skin to direct ultrasound waves towards the stone. Using ultrasound propulsion, the stones can then moved and repositioned to promote their passage, while burst wave lithotripsy (BWL) can break up the stone.
Unlike with the standard technique of shock wave lithotripsy, there is minimal pain according to lead author Dr M. Kennedy Hall, a UW Medicine emergency medicine doctor. “It’s nearly painless, and you can do it while the patient is awake, and without sedation, which is critical.”
The researchers hope that one day the procedure of moving or breaking up the stones could eventually be performed in a clinic or emergency room setting with this technology, Dr Hall added.
Ureteral stones can cause severe pain and are a common reason for emergency department visits. Most patients with ureteral stones are advised to wait to see if the stone will pass on its own. However, this observation period can last for weeks, with nearly one-fourth of patients eventually requiring surgery, Dr Hall noted.
Dr Hall and colleagues evaluated the new technique to meet the need for a way to treat stones without surgery.
The study was designed to test the feasibility of using the ultrasonic propulsion or using BWL to break up stones in awake, unanaesthetised patients, Dr Hall said.
The study recruited 29 patients; 16 received propulsion and 13 received propulsion and BWL. In 19 patients, the stones moved. In two cases, the stones moved out of the ureter and into the bladder.
Burst wave lithotripsy fragmented the stones in seven of the cases. At a two-week follow up, 18 of 21 patients (86%) 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, the study noted.
One of these patients felt “immediate relief” when the stone was dislodged from the ureter, the study stated.
The next step would a clinical trial with a control group, which would not receive either BWL bursts or ultrasound propulsion, to evaluate the degree to which this new technology potentially aids stone passage, Dr 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 anaesthesia, 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,” Dr Hall said.
Source: University of Washington School of Medicine/UW Medicine
