BY LYNNE JETER

Osteoporosis accounts for more than 700,000 spinal fractures in the United States every year, and vertebral compression fractures (VCFs) can result in kyphosis or dowager's hump, a debilitating condition characterized by chronic pain and increased mortality risk.

In years past, physicians relied on bracing combined with pain medication. Drawbacks included difficulty for elderly patients to tolerate narcotics that could be addictive and the fractures couldn't be reduced with bracing. The only way to restore height was with major surgery involving a rod, which patients viewed as a last resort.

Traditionally, when people were treated with narcotics and bracing, it could take months for them to get better.

In the early 1990s, researchers developed a minimally invasive procedure called vertebroplasty, where cement was injected into the fracture to strengthen the bone.

Unfortunately, surgeons were still unable to restore height with this method. To make matters worse, there were potential complications with cement leakage, which in some cases spread into veins and then into the lungs. Those patients could develop a pulmonary embolist from the glue, a potentially life-threatening complication. Also, the glue could leak into the spinal canal and potentially cause compression of the spinal cord or nerves, prompting weakness or paralysis.

Primary among vertebroplasty's drawbacks: while splinting the fracture, the vertebral body is left in a mechanically deformed state. Additionally, the more liquid cement had to be injected at higher pressure, which increased the risk of cement leakage into non-target tissues.

Some Arkansas surgeons are getting results in the repair of VCFs by using an innovative procedure called balloon kyphoplasty.

"There are some cases where it probably doesn't make a lot of difference whether you use vertebroplasty or kyphoplasty, but by and large, kyphoplasty is an overall better procedure," said Dr. Eric D. Akins, a neurosurgeon with Neurological Surgery Associates in Little Rock.

Kyphoplasty uses balloons within the vertebral body to restore the height of the bone and to create a cavity for injection of cement, which is more viscous and injected at much lower pressures. The restoration of bone height is a key advance that, in many cases, allows the altered mechanical forces affecting the deformed bone to be restored to a more normal state. This benefit can be seen in patient outcomes as improved level of function.

The kyphoplasty procedure is performed in a special radiology suite by trained interventional radiologists or in the operating room by surgeons. In many instances, the procedure can be performed under conscious sedation without the need for general anesthesia and its added risks.

In the minimally invasive procedure, surgeons insert a hollow cannula into the fractured bone, through which an orthopedic balloon is guided into the fracture. The balloon is inflated, raising the collapsed vertebra, while the soft inner bone is slightly compacted leaving a cavity inside the vertebra. Once the vertebra is in the correct position, the balloon is deflated and removed. Surgeons fill the cavity with cement that builds up the vertebra and holds it in place. The procedure usually takes under an hour.

Kyphoplasty also restores vertebral body height with a low risk of cement extravasation and it restores spinal alignment, a significant attribute because the stooped spine causes compression of many vital organs, making it difficult for patients to breathe, walk or eat properly. Some studies have shown that a high percentage of patients with compression fractures complained about chest pain when they didn't have heart problems. In some cases pain relief is reported immediately after surgery, while most others show reduction or elimination of pain within a couple of days.

While the majority of kyphoplasty procedures are for osteoporosis-related VCFs, surgeons are finding more uses for the treatment, for example with older trauma patients and cancer patients with compression fractures.

"If there's a pathologic fracture and we suspect there is tumor involved, we can biopsy the tumor using the instruments that come in the kyphoplasty set, which is very helpful," said Akin.

Europeans are experimenting with different filler substances to further improve kyphoplasty treatment outcomes. Instead of using acrylic cement that will remain in the same state year after year, they are using calcium extended with growth factors that may morph into bone.

"The closer you can come to the consistency of bone with the materials you're using, the better," said Akin. "Of course, if what you're using is harder than the bone you're injecting it into; you can actually cause problems with the adjacent bones. If they're coming up with a more like-bone substance filler so the bone can remodel itself, it's a good thing."

ie.
October 2006