THOUSANDS of kidney stone patients in Gwent were spared the surgeon's knife in the last ten years by lithotripsy - shock- wave treatment - and experts hope to get new equipment to keep up the good work.

Since a £500,000 fund-raising effort secured a lithotripter for New-port's Royal Gwent Hos-pital in 1995, all but the most urgent and difficult kidney stone cases have been treated with it.

Stones, which are mainly formed from a basis of calcium, are blasted with shockwaves to break them up with minimal discomfort, without the need for invasive surgery.

They are then passed naturally with little or no difficulty, ruling out the need for complicated, painful surgery, and lengthy hospital stays and recovery periods.

But the lithotripter - the only fixed-site machine in Wales - is nearing the end of its working life and urology specialists hope to persuade Gwent Healthcare Trust bosses to fund a new one. A machine and associated equipment will cost around £300,000.

"It has brought tremendous advantages for patients and staff," said consultant urologist Mr Richard Gower, an organiser of a fundraising effort during the late 1980s and early 1990s which paid for the current machine. "Kidney stones are small but can cause incredible pain. Ladies say it is even worse than the pain of childbirth.

"If they get dislodged and block the tube to the bladder they cause big problems. But they can be very difficult to find. With surgery, it could be up to three weeks in hospital and three months' recovery time, and even with keyhole surgery it is difficult.

"But with the lithotripter we bring people in, for treatment on consecutive days if necessary, and we can keep an eye on their condition. If further stones develop, we can treat them before they cause trouble.

"We bring in acute cases, control their pain, X-ray them, and treat the following day."

People across South Wales are often referred to the Royal Gwent, as the only other lithotripters available in the region are mobile units providing temporary cover at hospitals. Between 700 and 800 patients are treated every year, receiving a pre-determined number of shock- wave blasts per session on stones located by X-ray.