Patricia Kowalczyk had been suffering with neck and shoulder pain for years when her doctor offered her a shot of Botox.

The 60-year-old wasn't interested in smoothing her frown lines. But Johns Hopkins' Dr. Paul Christo wasn't offering the popular cosmetic procedure most often associated with the botulinum toxin that paralyzes nerves and muscles.

He wanted to give her one small, carefully aimed dose to knock out the ache that made daily activity a chore.

"Most of the public doesn't realize Botox is used for medical purposes," said Christo, an assistant professor of anesthesiology and critical care medicine in Johns Hopkins University School of Medicine's division of pain medicine. "Botox can have more than one effect. It can have a muscle and nerve benefit, and this allows people to do things they couldn't do before, like brush their hair or teeth."

Christo started using Botox about four years ago to treat a condition called thoracic outlet syndrome, a common condition that involves compression of nerves between the base of the neck and armpit. Symptoms include neck pain, headache, numbness and weakness down the arm.

The malady affects approximately 8 percent of the population, though doctors say it is under-reported. It is common in people who sit slouching in front of a computer all day, in athletes who use their upper bodies, in musicians and in accident victims like Kowalczyk. She had fallen and smacked her shoulder.

It is not the first time the toxin has been used to treat pain and other medical problems such as spasms, but Christo has refined a procedure by using a CT scan and a smaller dosage that lessens the side effects and increases the chance of pain relief. A study published in the April issue of the journal Pain Medicine found that patients got substantial relief for three months.

The procedure isn't necessarily going to end, or even significantly reduce, the number of surgeries that are highly successful in curing patients. But sufferers can get relief in the meantime, or improve their condition enough to try physical therapy, which can manage the condition.

Kowalczyk of Felton, Pa., said she probably will have surgery if doctors allow it. She wants the pain gone permanently, but she welcomed a break from her aches and an increase in range of motion.

The procedure is a two-step process that first involves a shot of local anesthetic. It dulls pain in a few hours and can help confirm the diagnosis of thoracic outlet syndrome. Diagnosis is difficult because the symptoms mimic other problems such as a bulging disk.

If the patient responds to the anesthetic, then Christo knows the patient probably has the syndrome and would respond to Botox, which takes longer to take effect but lasts longer. It also means the patient would likely be a good candidate for corrective surgery.

Patients return in a few days or weeks and go through the process again, this time with Botox.

Vivia Tucker of Darby, Pa., agreed to the test because she's lived with pain since a car accident two years ago. Physical therapy didn't work for the former nurse, and she was looking for an alternative to surgery. She initially said the anesthetic shot "hurt like hell" and felt like "someone was sitting on" her arm. But after a few minutes, the pain subsided.

She hadn't reported back to Christo a day later so he could not say whether she had thoracic outlet syndrome and would be a candidate for Botox.

The procedure for Botox is the same as for the anesthetic. Christo's team straps the patient down and rolls him into the CT scanner. A technician pulls up images of the patient's neck and upper body. Christo pinpoints an area at the center of the pain and uses a small needle to inject a contrast dye to confirm the location for the injection.

Not everyone believes Botox injections are a good idea. Dr. Carlos A. Selmonosky, a retired Virginia surgeon who treated thoracic outlet syndrome for years, said there are noninvasive ways to diagnose the malady but most doctors don't know them, such looking at the fingers to see if they're swollen.

Selmonosky, a vice president of the American TOS Association, says doctors should be better trained in diagnosis.

He said there can be problems with using Botox for treatment, because it can cause muscle weakness and make daily activities even harder. Patients would be likely to develop resistance with repeated use. And if physical therapy doesn't work in three months — and it doesn't in about 20 percent of cases —surgery is inevitable, he said.

"With Botox, relief is very temporary," he said. "But if you make the proper diagnosis and you get the patient to good physical therapy, work on their posture, you can have a tremendous amount of good results. If physical therapy doesn't work in three months, you still don't want a temporary cure."