Incidence of Osteopenia/Osteoporosis in Spine Fusion Patients

While it is common wisdom that the “silent killer,” osteoporosis, is under-diagnosed in the general population, specific data regarding the incidence rates of either osteoporosis or its precursor, osteopenia, is extremely rare for spine fusion patients.

A research team from the Hospital for Special Surgery (HSS) in New York City set out to collect such data for lumbar fusion patients. Their results, “Prevalence of Osteopenia and Osteoporosis Diagnosed by Quantitative Computed Tomography in 296 Consecutive Lumbar Fusion Patients” was presented at the recent meeting of the American Academy of Orthopaedic Surgeons in Las Vegas.

“The literature reporting [Quantitative Computed Tomography] QCT-based lumbar spine bone density is scarce, and we believe our study is the first of its kind,” said Alexander Hughes, M.D., an orthopedic surgeon specializing in spine surgery at HSS and senior investigator.

“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. We believe that QCT is more effective in screening patients because the DXA [dual energy x-ray absorptiometry] scan can overestimate bone density in the spine due to certain bone changes, a patient’s weight or physique, and other factors.”

The authors said, “There were no differences in prevalence between gender or race, but patients over age 50 were much more likely to be diagnosed with low bone density. Of these patients, 49% were diagnosed with osteopenia and 18% had osteoporosis. In patients under age 50, no individuals were found to have osteoporosis, but 17% had osteopenia. Within a subgroup of 212 patients with no prior history of low bone density, 39% were diagnosed with osteopenia and 10% had osteoporosis.”

Dr. Hughes told OTW, “I think the most important component of this is understanding that QCT is a more accessible and reliable means to establish the bone density of patients undergoing lumbar fusion surgery (all patients at our institution undergoing fusion receive a pre-op CT for diagnostic reasons). Furthermore, a much higher proportion of ‘healthy’ surgical patients have bone deficiencies that need to be considered in the perioperative period.”

“DXA is the more traditional modality for obtaining bone density information. However, most men do not obtain DXA studies (in fact often insurances won’t approve it). Furthermore, DXA is less reliable than QCT because it is more falsely impacted by patients who are overweight and by significant degenerative disease.”

“QCT is becoming the gold standard for the assessment of bone density in orthopedic patients. Orthopedists should understand that a much higher proportion of both men and woman undergoing orthopedic surgery are impacted by bone deficiencies than previously understood. Understanding this will impact perioperative decision making.”