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Stanford Report, September 22, 1999

New procedure uses bone cement to stabilize spinal fractures and alleviate pain

BY KRISTA CONGER

By injecting liquid bone cement directly into the cracks and crevices of a broken vertebrae, interventional neuroradiologists at Stanford are able to strengthen the fractured bone and provide permanent pain relief to people suffering from excruciating spinal fractures. Many patients for whom traditional methods have proven ineffective have experienced a dramatic improvement within 24 hours of the new treatment, researchers say.

"It's kind of like getting a cavity filled when you go to the dentist," said Huy M. Do, MD, of the minimally invasive procedure known as percutaneous vertebroplasty. But the pain associated with a fractured vertebrae makes a toothache seem trivial.

According to Do, an assistant professor of radiology at Stanford, about 750,000 new vertebral fractures occur each year in the United States, and about 115,000 of them result in hospitalization. The traditional treatment methods of bed rest, pain medication and back bracing are frequently insufficient at relieving the often debilitating pain associated with about 80 percent of the cases and which prevents some sufferers from leaving their beds.

In percutaneous vertebroplasty, Do and his colleagues insert a needle into the spine to reach the fracture site. They then inject a bone cement called polymethylmethacrylate (PMMA). In its initial liquid form, PMMA fills any cavities or spaces within the damaged bone. After an hour or two, the liquid hardens into a body-friendly cement.

"Tests have shown that it has strength and stress-resistance that is stronger than bone," said Do. This super-strong compound is able to shore up the fragile bone and support the broken vertebrae.

PMMA has been used as a bone replacement for many years in the United States, but percutaneous vertebroplasty has the advantage of being a minimally invasive procedure that does not require open surgery. According to Do, a typical treatment is performed under conscious sedation and local anesthetic on an outpatient basis, making the improvements all the more dramatic. Some patients who have difficulty standing due to the pain of the fractured vertebrae are able to walk out of the hospital the same day after vertebroplasty, and almost all experience significant or complete pain relief within 24 hours, he said. "It's really gratifying when these patients start to feel good again," said Do.

Do's colleagues in the procedure are Barton Lane, MD, professor of radiology, and Michael Marks, MD, assistant professor of radiology.

Do's arrival at Stanford in July from the University of Virginia marked the first time Stanford began to perform vertebroplasty. Do was trained to perform the procedure by its American pioneers, Mary E. Jensen, MD, and Jacques E. Dion, MD. Since July, seven patients have undergone the bone strengthening procedure at Stanford, and all seven have experienced complete pain relief. Studies at the University of Virginia with a larger number of patients indicate an overall success rate of 80 percent.

Despite the dramatic and lasting effects of vertebroplasty, it is offered at only a few institutions across the country.

"A lot of people don't know about this yet," said Do. "I think the key is to get the word out to patients because until now, the only treatment option available was rest and pain medication."

In the face of such gradual and uncertain improvement, vertebroplasty may seem like a godsend to many sufferers. Most of the patients treated at Stanford are elderly women with osteoporosis. Their weak bones are particularly susceptible to fracture, and once bedridden by an injury, it is difficult for them to regain their strength and mobility. Because vertebroplasty is performed under local anesthesia and typically takes only a few hours to complete, it offers patients a chance to resume a normal lifestyle within one day of treatment. While vertebroplasty does not protect against subsequent fractures in other vertebrae, the minimally invasive nature of the procedure lends itself to repeated treatments if necessary.

Although osteoporotic women have been the primary beneficiaries, vertebroplasty can also be effective for people whose spines have been weakened by metastatic cancer, chronic steroid usage or other types of bone disease.

"Anybody with a compression fracture that is painful is eligible," said Do. However, it is necessary to be certain that the patient's back pain is due to a fractured vertebrae and not some other compounding factor, he adds. Do turns away about one-third of his potential patients for that reason, referring them instead to Stanford's pain management clinic for alternative treatments. Additionally, patients with vertebral fractures in which the spinal canal itself is compromised are not good candidates for vertebroplasty.

Percutaneous vertebroplasty is covered by most private insurance companies and is covered in some areas by Medicare.

Do plans to discuss the treatment with other Stanford physicians during neurosurgical grand rounds October 15. to encourage them to consider vertebroplasty for their patients with painful vertebral fractures.

For more information about vertebroplasty, contact Do at 723-6767 or huymdo@stanford.edu. SR