Nelda and Gerry Winchester didn't know whether their daughter was alive as they battled early-morning traffic to get to Parkland Memorial Hospital in Dallas.

Mr. Winchester bounded out of the car before his wife could park.

Ms. Winchester, who was with friends and a passenger in her own car at the time of the accident, barely survived. She did not return home for nearly five months.

Early on, she could only shrug her shoulders. Doctors told the family that, with surgery, she would have use of her arms and wrists.

"They couldn't guarantee anything else, and couldn't guarantee she'd ever walk again," Mrs. Winchester said. "We were totally distraught over this. We were saying, 'She will walk again. You just don't know.' "

But as she started Physical Therapy, Ms. Winchester had her doubts.

"I just thought I wouldn't walk again they were so persistent about it."

The family then learned from other patients about stem cells, and soon they had Russia in their sights.

Stem cells are the body's building blocks. Scientists believe they can be coaxed to develop into specific cell types that can be used to replace damaged tissue and treat conditions such as diabetes, Parkinson's disease and spinal cord injuries. Experiments with paralyzed mice have shown that stem cells can help them walk again.

But the science behind repairing spinal cord injuries is extremely complex, said Robert H. Miller of the National Center for Regenerative Medicine.

"Stem cell therapies are so powerful, but the cells can only do what the Environment tells them to do," he said.

No evidence proves that simply injecting stem cells into a patient can heal the spinal cord, Dr. Miller said, and he worries that doing so would create more problems, including tumor growth.

Spinal cord injury patients are a close-knit network, thanks to Internet chat groups and message boards, said Dr. Steven Hinderer, medical director of the Center for Spinal Cord Injury Recovery at Rehabilitation Institute of Michigan.

About a third of the patients in his program have sought care abroad. He said the number has remained stable, though the countries that patients visit have varied. Many now are headed to Russia.

Dr. Hinderer said he does not endorse any procedure but keeps an open mind. He talks with patients about the risks and shares what information he has.

"People who are really negative about this whole thing will talk about how desperate [patients] are and anxious for recovery," Dr. Hinderer said. "They're also very well-informed."

Still, patients do not always listen when he steers them from procedures that don't offer much hope for improvement or that could be dangerous.

One patient traveled to Ecuador for surgery against his advice and died from complications.

"You're dealing with people who have been told to expect nothing," he said. "What do I really have to risk here, so why not?"

He said he has had patients whose conditions have worsened slightly but said many others have recorded improvements in sensations or circulation.

As Americans get more comfortable with the idea of going abroad for common surgeries to save money, more are seeking what they can't find here in hopes of improving – or saving – their lives, said Stephanie Sulger, director of international medical services for Medical Tours International.

"It moves fast, this industry," she said. Health providers abroad are eager to respond. "They think, 'Look at all these sick, rich patients.' "

She said her business, which has grown from a dozen patients in 2002 to about 300 a year now, gets several calls a week about stem cell therapies. The vast majority of current patients are going abroad for surgeries approved in the United States, but she expects that to change over time.