Senior investigator Alexander P. Hughes, MD, spine surgeon at HSS, explains, "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," adds Dr. Hughes.

Read the full article at RyOrtho.com.

The study enrolled patients undergoing lumbar spine fusion for a degenerative condition or spinal instability.

"The literature reporting QCT-based lumbar spine bone density is scarce, and we believe our study is the first of its kind," said HSS spine surgeon and senior investigator Alexander P. Hughes, MD.

"Spine surgeons should be aware of the high prevalence of abnormal bone mineral density in lumbar spine patients and the possibility that those without a previous diagnosis may have osteopenia or osteoporosis," Dr. Hughes said.

Read the full article at Becker's Spine Review.

However, a study presented today at the American Academy of Orthopaedic Surgeons (AAOS) 2018 Annual Meeting suggests that, at least in one type of spinal surgery, this may not be the case.

The authors report that in patients undergoing spinal fusions in their lower spine – known as the sacral region – a lower BMD alone may not increase the risk of sacral vertebral fractures. The findings suggest that surgeons should evaluate patients across a whole range of bone fracture risk factors, and not necessarily be reassured when a patient has a normal BMD.

"We better understand that there are many factors that impact bone 'quality'," says Hospital for Special Surgery (HSS) spinal surgeon Alexander P. Hughes, MD, who served as senior author on the new study. "It turns out that the mineral density measurement of bone alone may be less important than other factors. BMD is a measure of bone quantity, not quality." Among other factors that could increase sacral fracture risk are how the body maintains collagen, a connective tissue that helps maintain bone elasticity.

Dr. Hughes points out that while sacral fractures are rare, impacting less than 1 percent of fusion patients, when they do occur they can have serious consequences.

"Sacral fractures not only mean patients will have to undergo revision surgeries, they also may develop neurologic complications," he explains.

Dr. Hughes explains that previous data supporting a link between spinal surgeries and sacral fractures was purely anecdotal, and that some prior reports suggested that only a small percentage of patients sustaining sacral fractures after fusion surgery had osteoporosis. To test whether or not this is case, he and a team of his HSS colleagues reviewed BMD scores in patients who had experienced sacral fractures following a spinal fusion surgery and those who had not. They also employed an experimental application of qCT that allows an assessment of the BMD of the sacrum itself.  Neither decreased global BMD or sacral BMD was found to differ significantly between the two groups.

The new study is part of a larger research initiative at HSS aimed at better understanding and treating disorders of the bone and other connective tissues. Dr. Hughes feels the findings could have implications for other spinal surgeries and orthopedic procedures as well.

"This could have direct implications on surgical decision making,” he says. “We’re realizing that bone mineral density has its limitations."