Compression fractures of the vertebra – typically caused by osteoporosis – are often treated with vertebroplasty, a procedure in which bone cement is injected to secure the fractured bone and relieve pain. It sounds like a logical solution and the number of these procedures has been on the rise in recent years, but two new studies reveal that it may be ineffective.
David Kallmes, MD, a Mayo Clinic (Rochester, Minnesota) physician who specializes in radiology and neurosurgery and a study leader, said that when he initiated a trial to test the theory, he had no idea there was no benefit derived from the cement. "I thought we'd enroll 20 people and they would say we're showing big benefits and we'd stop. But they never told us to stop," he told Medical Device Daily.
In both the U.S. study and another performed in Australia, participants had equivalent pain relief whether they had the cement injected or just the local anesthetic.
Researchers from eight medical centers in the U.S., UK and Australia enrolled a total of 131 patients in the trial divided into two groups: one group had vertebroplasty while the other, the control group, had a simulated procedure without cement, but included injection of lidocaine. Within days of treatment, both groups reported similar improvements in function and pain.
"I really don't know why," Kallmes said. "You have to anesthetize skin and bone for all patients so it may be partially related to that, but lidocaine is short acting, so it could be the placebo effect."
But because the results of Kallmes' study were duplicated in another, "It gave me more confidence in my results," he said.
The other study was not related to Kallmes', but used the same methods with 78 patients.
"I was aware of that trial, but it was completely independent, although they decided to gather the same data," he said.
Both studies appeared last week in the New England Journal of Medicine (NEJM) along with an editorial that puts the number of vertebroplasty procedures performed in the U.S. at 8.9 per 1,000 people, a figure that has doubled in recent years.
So if it's clear the cement isn't doing the intended job, why not just stop using it? Kallmes pointed out that there's some level of pain reduction.
"We aren't saying the vertebroplasty doesn't work, because it somehow does," he said. "Both sets of patients experienced significant improvements in pain and function a month following the procedure, whether they received cement injections or not. Improvements may be the result of local anesthesia, sedation, patient expectations, or other factors."
There is a downside to the use of cement, whether it does the intended job or not. It can seep into the lungs, spinal canal or cause risk of new fractures.
"It's not totally benign and is a permanent medical implant with potential downsides," Kallmes said. "Now I think we should encourage patients to give medical treatment a full go. We should take a deep breath and dial back on enthusiasm for vertebroplasty."
The other study was led by Rachelle Buchbinder, PhD, of Monash University (Malvern, Australia), who concluded "We found no beneficial effect of vertebroplasty as compared with a sham procedure in patients with painful osteoporotic vertebral fractures, at one week or at one, three or six months after treatment," she wrote in the NEJM.
Kallmes said that because these two trials raised as many questions as it answered, he's preparing to launch a new study for further investigation with a new variable – the absence or presence of local lidocaine.
Lynn Yoffee, 770-361-4789; firstname.lastname@example.org