A review of percutaneous kyphoplasty

A procedure that fills in fractured vertebrae with injected cement has not been shown to improve a person's back pain or quality of life, according to a new analysis of studies.

The procedure, known as percutaneous kyphoplasty, does seem to expand areas of collapsed backbone and restore some vertebral height in patients with osteoporosis, although the studies did not offer enough information to precisely measure the magnitude of these improvements, the researchers found.

The lack of studies directly comparing kyphoplasty to more simple treatments such as bed rest "prevented us from being able to determine whether percutaneous kyphoplasty improves patients' pain, functional ability or quality life," the review authors conclude.

The review is published by ECRI, a nonprofit health services research agency that produces technology assessments on medical devices, drugs, biotechnologies and procedures.

A surgeon performing percutaneous kyphoplasty inserts a balloon into a patient's fractured vertebrae, inflates the balloon and fills the space created by the balloon with bone cement. A similar procedure called vertebroplasty injects bone cement directly into the vertebrae.

"The aim of vertebroplasty is to stabilize the fractured vertebral body, while the goals of kyphoplasty are to stabilize the vertebral body and to restore its height to as near its prefracture level as possible," said Gladius Lewis, Ph.D., a biomechanics and biomaterials research at the University of Memphis.

The goal of both procedures is to strengthen crushed or compressed vertebral bone in people with osteoporosis and multiple myeloma patients who suffer from severe bone tumors.

"In principle, such treatment may prevent further fracture or collapse of the bone," the ECRI authors say.

Compression fractures in the porous bone of the spine can cause pain and reduce mobility, and may lead to a stooped posture that squeezes the chest cavity and interferes with lung function.

In the United States, 15 percent of women and 5 percent of men will probably have at least one such fracture in their lifetimes, although they often go unnoticed because people attribute the pain to arthritis or simply old age, the ECRI authors say.

Kyphoplasty is only recommended for people who still have pain and reduced mobility after trying more conservative treatments such as bed rest, anti-inflammatory medicines and physical therapy. Kyphoplasty is not recommended for certain severe fractures and spinal infections.

The ECRI review looked at 16 studies of percutaneous kyphoplasty, mostly in osteoporosis patients. The procedure was performed in both the lumbar (lower back) and thoracic (middle back) vertebrae.

"To the best of our knowledge, we don't believe there is any evidence out there that would suggest kyphoplasty is more effective when used on lumbar or thoracic vertebrae," said Dr. Stephen Tregear, director of special projects for ECRI.

None of the patients in the 16 studies died as a result of kyphoplasty. Leaking bone cement was the most common side effect of the treatment, occurring in up to 34 percent of vertebrae. Although leakage is common, it rarely causes problems for patients, Tregear says.

Although there has been a lot of research on injectable bone cements, few critical reviews compare different types of cement and their properties, Lewis said. Different cement fillers were not compared in the ECRI study, Tregear said.

The U.S. Food and Drug Administration issued a warning about serious complications related to the use of bone cement and bone-void fillers in treating compression fractures of the spine and has extended the warning to apply to all types of bone cement and bone-void fillers that are not specifically cleared and labeled for kyphoplasty.

According to the ECRI study authors, kyphoplasty costs $3,400 to $4,000 for the kyphoplasty materials and $8,000 to $10,000 in doctor and hospital fees. Health insurance carriers vary in their coverage of the procedure, and the Centers for Medicare and Medicaid Services have not set a national coverage standard for kyphoplasty.