Study shows CT scans effective in diagnosing low bone density

Register now

Computed tomography scans done before spinal fusion surgery have been shown to be effective in finding patients with undiagnosed low bone density.

A study at the Hospital for Special Surgery in New York found the CT scans were effective in finding osteoporosis. The researchers say that making this diagnosis is an important consideration in spinal fusion surgery, because low bone density could affect the treatment plan before, during and after the procedure.

During the study, almost half of the nearly 300 patients tested were diagnosed with osteoporosis or its precursor, osteopenia, for the first time. Some, but not all, had undergone a prior DXA bone density scan. Results of the study were presented at the American Academy of Orthopaedic Surgeons’ annual meeting.

Metabolic bone disease is a major public health concern. In 2010, the U.S. prevalence of low bone mineral density in adults 50 and older was 44 percent, and 10.3 percent had a diagnosis of osteoporosis, noted clinicians at the Hospital for Special Surgery.

"Low bone density is a known risk factor for vertebral fractures, and there is a recent emphasis by spinal surgeons to evaluate and treat this prior to elective spine fusion," says Alexander Hughes, MD, an orthopedic surgeon specializing in spine surgery at the hospital and senior investigator on the research project.

The standard test to measure bone strength is dual energy X-ray absorptiometry (DXA or DEXA), a type of flat X-ray that reads bone mineral content. Quantitative computed tomography (QCT) measures bone mineral density with a CT scanner, resulting in a 3D image.

"The purpose (of our study) was to measure lumbar spine bone density using QCT and determine the prevalence of osteopenia or osteoporosis in patients undergoing lumbar spine fusions,” Hughes says. “We believe that QCT is more effective in screening patients because the DXA scan can overestimate bone density in the spine due to certain bone changes, a patient's weight or physique, and other factors."

If a patient is found to have osteoporosis or osteopenia prior to spinal fusion, the treatment plan may be modified, including the type of implants used. "We now have newer technologies in terms of the hardware we use in spinal fusion that are better suited to patients with low bone density," Hughes explains. "Secondly, we're in a kind of renaissance as far as treating metabolic bone disease. We now have a newer generation of medications that can improve bone health and bone biology. If someone is diagnosed with osteoporosis, we may start them on one of those medications either before or after surgery."

For reprint and licensing requests for this article, click here.