Scientists said Friday they had developed a revolutionary "spray-on skin" treatment for venous leg ulcers -- a common ailment involving a shallow, open and stubborn wound on the ankle or lower leg.

Using a spray of skin cells suspended in a mixture of proteins that aid blood clotting, the team treated 228 patients in the United States and Canada and found it greatly improved and accelerated wound closure.

"The treatment we tested in this study has the potential to vastly improve recovery times and overall recovery from leg ulcers without the need for a skin graft," said researcher Herbert Slade of Healthpoint Biotherapeutics in Texas.

The patients also had their wounds bound with compression bandages, the standard treatment.

Venous leg ulcers affect about one person in 500 in the UK, but the rate increases sharply with age to one in 50 over the age of 80, said a media statement on the report published in The Lancet medical journal.

The ulcers develop when persistently high blood pressure in the veins of the legs damages the skin. They affect mainly people who are unable to move properly like the old and obese, and those with varicose veins.

Standard treatment involves compression bandages, infection control and wound dressing, but not all the wounds heal.

Skin grafts are sometimes used, but these result in a new wound at the spot where the graft is taken from.

In a comment that accompanied the paper, scientist Matthias Augustin of the University Medical Center Hamburg said it was crucial to find new therapies as venous ulcers were common and burdensome to patients.

"Non-healing ulcers are a substantial economic burden," he wrote. "In Germany, for example, annual total costs of venous leg ulcers amount to about 10,000 euros per patient."

Spending more on treatment by including cell therapy would pay off in the long run by improving patient healing, he argued.