SOUTHAMPTON surgeons are using a new laser technique to dust away the surface of large kidney stones and make them "crumble like popcorn".

Known as dusting and pop-dusting, it involves using a low energy beam first to break down the soft outer shell of a stone.

Once it has reduced in size, the laser is switched to a higher frequency to ‘pop’ the hard centre into tiny pieces which can then pass through the urine.

Patients with stones larger than 1.5cm require two to three sessions of laser treatment over a period of up to three months or, if unsuccessful, may need to undergo keyhole surgery.

This minimally invasive procedure, which takes less than an hour, involves inserting a ureteroscope, which is a thin tube used for viewing, into the kidney via the bladder to visualise stones before removing them using a small laser fibre.

Kidney, or renal, stones develop when crystals of salt accumulate into stone-like lumps and are not flushed out of the body.

The technique has now been used more than 80 times by Professor Bhaskar Somani, a consultant urological surgeon at University Hospital Southampton, and his team.

Results published in the journal Urolithiasis showed the combination of dusting and pop-dusting left 93 per cent of patients stone-free after one treatment.

Prof Somani, a professor of urology at the University of Southampton, said: “Large stones can be very difficult to treat and, routinely, would require two or three laser treatments or surgery.

“Using this technique means we can treat very large stones - up to 5cm - in a single session of less than an hour with a fantastic stone-free rate.

“The thought process has long been that having a laser to treat stones means blasting them at full force to destroy them, but that means they disperse into fragments which cannot always pass through the system.

“By dusting the outer layer first at low energy, we can steadily reduce the size of a stone before breaking the core into smaller pieces that can crumble like popcorn and pass out of the body smoothly.”

Prof Somani and his team will also present their findings of a study into the use of the technique in children at the World Congress of Endourology in Abu Dhabi in October.