Washington, June 11 (IANS) Well known for smoothening wrinkles when injected in the face, Botox , a toxin known to weaken or paralyse certain nerves and muscles, may have uses that go beyond the cosmetic.

Johns Hopkins researchers have found that patients with a debilitating nerve compression disorder called thoracic outlet syndrome (TOS) reported a significant reduction in short-term pain after receiving a single, low-dose injection of Botox in a muscle located in the neck.

Researchers say findings suggests Botox is a safe, non-invasive alternative to the syndrome's treatment of last resort: surgery to remove the first rib and sever one of the muscles in the neck.

"There haven't been many alternatives to the use of surgery to treat this syndrome," says Paul J. Christo, assistant professor of anesthesiology and critical care medicine at the Johns Hopkins University School of Medicine, who led the study.

TOS is caused by a compression of nerves in the lower neck, which occurs when there is not enough room in the cavity between the base of the neck and the armpit (the thoracic outlet) for nerve impulses to freely pass through.

Symptoms often develop in the neck or head and tend to shoot down the arm, causing often excruciating pain, numbness and/or weakness in the limb and extremities.

Christo and his colleagues evaluated patients who were candidates for surgery to treat their TOS.

Each was given a 20-unit injection of Botox, a brand-name drug that contains botulinum toxin, made from the same bacterium that causes botulism, a paralysing and life-threatening form of food poisoning.

Patients experienced a significant decrease in pain in each of the first two months after the injection. At three months, patients still felt a 29 percent decrease in their TOS-related pain as measured on a scientific pain scale.

"This modest amount of pain reduction can have a significant impact on a patient's life," says Christo, a pain medicine specialist. "For many, it allows them to do what they couldn't do before - brush their hair, brush their teeth, hold their child."

The effects of the drug begin to wear off in a few months, as they do when Botox is injected into facial wrinkles.

Christo says patients should be able to receive repeated injections of Botox into the muscle over time, though some could develop antibodies to the compound with excessive use, which would mean the toxin would no longer block pain.

In the study, 48 percent of patients went on to have surgery. Others tried the Botox technique in the hope that they could avoid having surgery, he says.

Not all patients are candidates for Botox, says a Johns Hopkins release.

These findings were published in the April issue of Medicine.