NASA-funded technique allows doctors to remove kidney stones without anesthesia

A new technique sees the combination of two ultrasound technologies in order to move kidney stones out of the ureter with no anesthesia, according to a press release by the University of Washington School of Medicine and UW Medicine published on Friday.

Ultrasound waves push stones

The new technique sees a physician use a handheld transducer placed on the skin to direct ultrasound waves towards the stone. The ultrasound can then be used to move and reposition the stones to direct their safe passage; a process called ultrasound propulsion, or the break up the stone, a technique called burst wave lithotripsy (BWL), all while the patient is awake and feeling minimal pain.

Compared to conventional procedures now in use for kidney stone removals that are very painful and require sedation, this technology doesn't hurt, said 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,” he added.

The development could now mean that kidney stone removals will be performed in a clinic or emergency room setting, said Hall.

Recent research by UW Medicine indicates that one in 11 Americans will have a urinary stone over the course of their lifetime with this number constantly increasing. In addition, up to 50 percent of patients with a stone event will recur within five years, the research further indicated.

This is why Hall and colleagues believe it is crucial to come up with ways to treat kidney stones that are safe, efficient, and painless. The team evaluated their new technique to see its potential in meeting the need for a way to treat stones without surgery and without sedation.

Twenty-nine patients took part in Hall’s study. Sixteen were treated with propulsion alone while 13 received propulsion and burst wave lithotripsy. In 19 patients, the stones moved and in two cases, they even redirected themselves out of the ureter and into the bladder.

Meanwhile, 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,” the researchers noted in their statement.

One patient even reported feeling "immediate relief" when the stone was moved away from the ureter, the study indicated.

Clinical trials to be undertaken next

Now the researchers are looking into a clinical trial with a control group, which would not receive either BWL bursts or ultrasound propulsion, to estimate the degree to which this new technology works.

Research into this new technology first started five years ago with NASA funding. The space agency was looking to see if kidney stones could be handled without anaesthesia on long space flights. The resulting technology was so efficient that NASA has now downgraded kidney stones as a key concern.

"We now have a potential solution for that problem," Hall concluded.