It used to be that a patient with osteoporosis who broke a vertebra was pretty much out of luck. The only recourse was wearing a back brace and waiting to heal. If the searing pain was unbearable, it could be blunted with powerful narcotics.
But in the past few years, doctors have been offering and patients demanding what some call a miraculous treatment: vertebroplasty (pronounced vur-TEE-bro-plasty), in which a form of cement is injected into the broken spinal bone.
No one is sure why it helps, or even if it does. The hot cement may be shoring up the spine or merely destroying the nerve endings that transmit pain. Or the procedure may simply have a placebo effect.
And some research hints that the procedure may be harmful in the long run, because when one vertebra is shored up, adjacent ones may be more likely to break.
But vertebroplasty and a similar procedure, kyphoplasty, are fast becoming the treatments of choice for patients with bones so weak their vertebrae break.
The two procedures are so common, said Dr. Ethel Siris, an osteoporosis researcher at Columbia University, that "if you have osteoporosis and come into an emergency room with back pain from a fractured vertebra, you are unlikely to leave without it." She said she was concerned about the procedures' widespread and largely uncritical acceptance.
In three years, the number of vertebroplasties nearly doubled, to more than 27,000 in 2004 from 14,000 in 2001. Despite the lack of rigorous evidence that the procedures work, most were covered by Medicare, at a cost of $21 million last year. (There is even less data on the effects of kyphoplasty, which involves pumping the vertebra with a balloon to restore its shape before injecting cement.)
Even proponents would like to know whether cement injections really help in the long run, but medical scientists fear they may never know.
In 2002, a group of researchers received a federal grant for a clinical trial that would be the first to rigorously assess vertebroplasty. But their study is faltering.
Patients in severe pain have proved unwilling to enter such a trial, in which they might be randomly assigned to get a placebo, and their doctors have been reluctant to suggest it. In 18 months, the investigators have been able to persuade just three medical centers to recruit patients, and only three patients have enrolled.
Now the investigators are looking for centers overseas, but they agree that the study's prospects are dim and that its failure would leave critical questions unanswered.
"Whose responsibility is it to decide that something should be part of medical practice without adequate evidence that it works?" asked Dr. Jeffrey G. Jarvik, an investigator with the study and a neuroradiologist at the University of Washington.
But for many doctors, the time to ask is long past. Whatever the evidence, they say, too many people are convinced that the procedures work.
"I struggle with this," said Dr. Joshua A. Hirsch, director of interventional neuroradiology at Massachusetts General Hospital in Boston. He believes in clinical trials, he said, but when it comes to vertebroplasty and kyphoplasty, "I truly believe these procedures work."
"I adore my patients," Dr. Hirsch added, "and it hurts me that they suffer, to the point that I come in on my days off to do these procedures."
Vertebroplasty came to the United States in 1993 when Dr. Mary E. Jensen and Dr. Jacques E. Dion, interventional neuroradiologists at the University of Virginia Health System, were confronted with a woman with breast cancer that had spread to her spine. Conventional medicine had nothing to offer for her excruciating, unrelenting pain.
But they remembered a lecture by a French doctor who said she had injected a form of cement into the vertebrae of cancer patients and said it relieved their pain. She did not, however, explain how to do it.
So Dr. Jensen and Dr. Dion began mixing up various concoctions of polymethylmethacrylate, a cement approved by the Food and Drug Administration for attaching bone to implants. (Surgeons can try new procedures without F.D.A. approval and can use approved substances in new ways at their discretion.)
"We've never tried this before," Dr. Jensen said they told the cancer patient. "But it's all we have to offer." With trepidation, they injected the cement.
"The next day," Dr. Jensen said, "her pain was gone."
Then they saw two men with severe compression fractures of the spine caused by osteoporosis. After practicing on spines from cadavers, the two doctors treated the men with cement. Again, their pain went away.
"We said, 'O.K., now we may actually be on to something,' " Dr. Jensen recalled. In November 1997, she and her colleagues reported on 29 patients. Twenty-six, they said, "reported significant pain relief immediately after treatment."
Dr. Jensen was won over.
"Anyone who goes from a pain scale of nine to a pain scale of two within 48 hours, I'm sorry, but I just do not believe it is a placebo or natural history," she said. "These were people who had been in unremitting, relentless pain for weeks."
Wanting to get the procedure to more patients, Dr. Jensen asked established companies to make the cement mix. They refused, so she and Dr. Dion joined forces with a biomedical engineer to found their own company. She trained hundreds of doctors in weekend sessions. And she and her colleagues lobbied local insurance carriers with Medicare contracts to pay for the technique.
"Four years ago, we were the only hospital in a 100-mile radius to offer it," Dr. Jensen said. "Now all the community hospitals offer it."
But Dr. David F. Kallmes, one of her partners, wanted a rigorous test. He began a pilot study, randomly assigning participants to vertebroplasty or placebo. To make it more appealing, he told patients that 10 days later they could get whichever treatment they had failed to get the first time.
It was hard to find subjects, and Dr. Kallmes ended up with only five. For the sham procedure, he pressed on the patient's back as if injecting cement, injected a local anesthetic, opened a container of polymethylmethacrylate so the distinctive nail-polish-remover smell would waft through the air and banged on a bowl so it sounded like he was mixing cement.
In 2002, he reported his results: three patients initially had vertebroplasty and two had the sham. But there was no difference in pain relief. All the patients thought they had gotten the placebo, and all wanted the other treatment after 10 days. One patient who had vertebroplasty followed in 10 days by the sham said the second procedure - the sham - relieved his pain.
That experience convinced Dr. Kallmes that it was possible, and important, to do a larger randomized trial, so he won a grant from the National Institute of Arthritis and Musculoskeletal and Skin Diseases for the study that is under way. Dr. Kallmes, now at the Mayo Clinic, said he had high hopes for vertebroplasty but recognized that reports of its effectiveness might be misleading.
"There are a number of biases in the procedure and in the way the data is collected," he said. Previous studies, he said, have "mostly been done by people like me without a background in statistical methods."
For example, he said, patients come in crying for relief when their pain is at its apogee. By chance, it is likely to regress whether or not they are treated. That phenomenon, regression to the mean, has foiled researchers time and time again.
And there are other questions, said Mary Bouxsein, a bone biomechanics researcher at Harvard Medical School. One study, by Dr. Terrence Diamond of St. George Hospital in Sydney, Australia, found that after six weeks, patients who had vertebroplasty had no better pain relief than those who did not.
So are vertebroplasty and kyphoplasty worthwhile in the long run?
"When you think about what's in the spine, it's vertebral bodies with disks in between," Dr. Bouxsein said. "The disk is like a little spring that absorbs load.
"When you put cement in there," she continued, "you change the biomechanics of how the load is transferred, and that increases the stress on the vertebrae above and below. In an osteoporotic patient who is already at risk for spine fracture, that may not be what you want to do."
Some small studies have found a suggestion of high fracture rates in vertebrae adjacent to those injected with cement. And Dr. Bouxsein and others, testing spines from cadavers, found they fractured more easily if one of the vertebrae was filled with cement. "It's a tough issue," Dr. Bouxsein said. If a patient gets profound and immediate pain relief, that alone may make the procedure worthwhile, she said. Or, then again, it may not.
Patients tell a variety of stories, not all with happy endings.
Jacqueline Gosselin, 76, of Winslow, Me., was consumed with pain after two of her vertebrae collapsed. She spent weeks in the hospital and was unable to walk for months. Seven months after her injury, she had kyphoplasty.
At first she thought she had improved, she said, but "I've gone downhill ever since." The pain is now about the same as before the procedure, she said, adding, "I'm still looking for help."
An osteoporosis patient, Stanley Stanton, a 58-year-old foreman in Owatonna, Minn., broke vertebrae by simply twisting his torso one day this spring. The pain was so bad that he could hardly walk. But after vertebroplasty, he said, "I walked out of there two hours later and I was 300 percent better." That was in June; today he needs only an occasional over-the-counter pain reliever.
Doctors say they have seen patients who got no relief. But what really popularized the procedure, they say, were unforgettable stories of people like Mr. Stanton with unbearable pain who got their lives back.
Dr. Jensen knows firsthand how powerful such stories can be. In the late 1990's, when vertebroplasty was new and many doctors were looking askance at it, she gave a talk to a group of doctors in Chicago.
"I could tell by looking at the audience that no one believed me," she said. When she finished, no one even asked questions.
Finally, a woman in back raised her hand. Her father, she told the group, had severe osteoporosis and had fractured a vertebra. The pain was so severe he needed morphine; that made him demented, landing him in a nursing home.
Then he had vertebroplasty. It had a real Lazarus effect, the woman said: the pain disappeared, the narcotics stopped, and her father could go home.
"That was all it took," Dr. Jensen said. "Suddenly, people were asking questions. 'How do we get started?' "
But Dr. Siris, of Columbia, said such astonishing reports were just part of the story. "Clearly, many patients have these procedures and the pain does go away," she said. "But what are the risks to the rest of the spine in terms of more fractures? That's the dilemma.
"It's a technique that's crying out for clinical trials," Dr. Siris went on. But with only patients' stories as evidence, the procedures "are being offered to patients without fair information and without truth in advertising."