‘Smart stethoscope’ could aid kidney stone treatment

Doctors trialling a new ‘smart stethoscope’ have found that it could halt unnecessary treatment of kidney stones even earlier than previously thought.

The device, which allows doctors to listen to the shock waves used to break up kidney stones inside the body, was designed by researchers at Southampton University and Precision Acoustics for assessing whether a course of treatment has been successful.

Now, clinical trials at Guy’s and St Thomas’ Foundation Trust (GSTT) have shown that the technology can also indicate whether a course is working and is worth continuing before it has even finished — potentially helping to avoid any side effects.

The ‘stethoscope’, which received an Engineer Technology & Innovation Award in 2008, works by analysing the sound of the shock waves as they echo around the body to determine whether each one has affected the stone.

Assessment was previously carried out after the patient had been given 3,000 shock waves but has now been shown to be useful much earlier in the process — after jut 500 shocks.

Prof Tim Leighton

If more than half of the shocks are successful, the treatment (known as shock-wave lithotripsy or SWL) is deemed to be worth carrying on, said project leader Prof Tim Leighton of Southampton’s Institute of Sound and Vibration Research.

‘At 500 shocks, our device can tell you if a stone is going to break or not,’ he told The Engineer. ‘That’s crucial because at 500 shocks you’ve not had any of the side effects setting in.’

Then doctors can decide whether the treatment is worth continuing, he said. ‘Or we might be able to say: “Stop this, this will never break through shock waves”.’

He added: ‘You might have a stone that breaks really easy and shatters at about 500 shocks, in which case the last 2,500 shocks wouldn’t help you medically — they’d just give you kidney damage.’

Dr Fiammetta Fedele of GSTT said in a statement: ‘When placed on the patient’s skin this sensor diagnoses successful SWL treatments (with 94.7 per cent accuracy in clinical trials, compared to the 36.8 per cent achieved by clinicians with the current state-of-the-art equipment suite).’

The researchers have published a paper on the latest clinical trials in the journal Proceedings of the Royal Society A, which also discusses the importance of moving from computer simulations to real-world trials with this kind of technology at the right time to get maximum benefit from the trials.