March 17 (HealthDay News) -- A new treatment can help save severely frostbitten limbs that might otherwise be amputated, researchers say.

In cases of severe frostbite, deep tissue freezing can damage muscles, tendons, nerves and blood vessels; often leading to gangrene and limb amputation, according to background information in the study.

When severe frostbite occurs, blood vessels are affected and blood flow is blocked. But small clots can also form when the blood vessels are thawed and re-warmed, and spasm of the damaged arteries further obstructs blood flow to the smallest blood vessels, the U.S. team notes.

This study included 17 patients, aged 16 to 65, with severely frostbitten hands and feet. Interventional radiologists used angiography (an X-ray exam of arteries and veins) to identify areas lacking blood flow. They then delivered, via catheter, clot-busting and anti-spasmodic drugs to reopen damaged, clogged arteries.

This approach proved highly successful in saving limbs and preventing amputation. The findings were to be presented Monday at the annual meeting of the Society of Interventional Radiology in Washington, D.C.

"Previously, severe frostbite was a one-way route to limb loss. This treatment is a significant improvement. We're opening arteries that are blocked so that tissue can heal and limbs can be salvaged. We were able to reopen even the smallest arteries, saving patients' fingers and toes," Dr. George Edmonson, an interventional radiologist with St. Paul Radiology, in St. Paul, Minn.

In this study, six patients received the clot-busting drug Tenectaplase while 11 received another drug, Retaplase. The researchers wanted to find out if the greater plasma stability of Tenectaplase would lead to better patient outcomes.

"With both groups, approximately 80 percent of the patients' affected limbs, fingers and toes responded with significant improvement. The treatment has been demonstrated to be safe and beneficial. We will continue research to improve and modify the protocols," Edmonson said.

SOURCE: Society of Interventional Radiology, news release, March 17, 2008