A latest research by researchers at Hospital for Special Surgery (HSS) in New York City says the microscopic structure of bone appears to predict which patients will experience poor outcomes after spinal fusion.
In the US, spinal fusion is among the most commonly performed orthopedic surgeries, with more than 400,000 patients undergoing the procedure each year.
Despite most cases being successful, as many as 45 percent of patients experience complications after the operation, often resulting from the bone’s inability to tolerate the hardware surgeons use to support the skeleton.
A team led by Emily Stein, MD, an endocrinologist and bone specialist, along with spine surgeons Han Jo Kim, MD, Matthew Cunningham MD, PhD, and Frank Schwab, MD, turned to a cutting-edge technique for assessing bone called high-resolution peripheral quantitative computed tomography (HR-pQCT).
According to Dr Stein, “DXA provides a two-dimensional measure of bone density, or the amount of bone present, whereas HR-pQCT provides a true three-dimensional measurement of the bone density.”
This provides additional information about the structural features of bone that can be leading to weakness or fragility, Stein added.
The most widely used technology to evaluate patients’ bones before spine fusion surgery is called dual x-ray absorptiometry, or DXA. DXA imaging gives physicians a rough sense of the strength of a person’s bone, but it is not foolproof. In some cases, surgeons find that patients whose DXA scans appear normal have bones that are so weak that the appliances they use during spinal fusion are at risk of failure.
HR-pQCT can separately measure how much bone is in the outer (cortical) and inner (trabecular) compartments and measure on a microscopic level how the inner trabecular bone network is organized, including the number, thickness and spacing between the parts of that network called trabeculae.
These measurements—known broadly as the microarchitecture—may provide a much more robust assessment of skeletal health than DXA, particularly in this population of patients who frequently have changes in the area of the fusion which undermine the utility of DXA.
Men & Women
The research included 54 men and women scheduled for spinal fusion at HSS between December 2017 and December 2019. Patients underwent conventional DXA scans, as well as HR-pQCT scans of the radius (forearm) and leg bone (tibia).
Out of the 54 patients in the study, 14 experienced complications within the first six months of surgery, including broken rods, loosened bone screws, fractures and abnormal bending of the spine.
Though the number of people in the study was small, the researchers found that those with abnormalities on HR-pQCT were significantly more likely to experience complications than those without such defects — abnormalities that were not evident on DXA imaging.
(With inputs from The OnLook News Research Bureau)