Kidney Stone Monitor Boosts Treatment Effectiveness

Tim Leighton (University of Southampton)

Engineers at University of Southampton in the U.K. tested a prototype monitoring device for ultrasound treatments of kidney stones that showed the device ready for full-scale clinical trials. The team led by Southampton engineering professor Tim Leighton published its findings yesterday online in the journal Proceedings of the Royal Society A (paid subscription required).

In the paper, Leighton (pictured left) — with colleagues from Institute of High Performance Computing in Singapore and the U.K.’s Atomic Weapons Establishment — reported on tests of a device developed in collaboration with the company Precision Acoustics in Dorchester, that tracks the progress of ultrasound treatments for breaking up kidney stones. The condition, caused by crystals that form into stones in the kidney that block the urinary tract, can result in severe pain, and the number of cases appears to be increasing in the U.S. and Europe.

A common treatment for kidney stones is lithotripsy, a non-invasive procedure that uses ultrasound to break up the stone so it can pass through the urinary tract. The problem for clinicians treating kidney stones with lithotripsy is they cannot accurately monitor the progress of breaking up the stone, and in more than half the cases, patients are sent home with the stone still not able to pass out. As a result, these patients often still encounter the extreme pain from the stone and must return to the hospital for further treatments.

The Southampton device, called a “smart stethoscope,” listens in to the ultrasound treatments and monitors the sound waves hitting the stone, returning noticeable differences in echoes between intact and fragmented stones. The research published this week tracked the decision-making process from testing the device with computer simulation to full clinical trials, a key point in the development of a medical device with human and financial implications.

As Leighton explains, “if the move is taken too early, the expensive clinical trials do not have adequate underpinning science and engineering, resources are wasted, and the eventual patient benefit is delayed. But conversely if the decision to move is taken too late, then the positive benefits to patients can be delayed for years.”

The research enabled the team’s corporate partner, Precision Acoustics, to develop the lab prototype into a working device for clinical trials. In those trials at hospitals in London, the monitoring device detected some 95 percent of successful lithotripsy treatments, compared to 37 percent for clinicians without the benefit of the device. The university says experience with the device  also shows it can help clinicians decide if the patient has received enough ultrasound therapy, and thus avoid over-treatments.

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