The distribution of bone mass in the lumbar vertebrae: are we measuring the right target?

• Published in: The spine journal 2015-11, Vol.15 (11), p.2412-2416
• Main Authors: Wang, Yue, MD, PhD, Videman, Tapio, MD, PhD, Boyd, Steven K., PhD, Battié, Michele C., PhD
• Format: Article
• Language: English
• Subjects: Bone Density; Bone mineral density; DXA; Humans; Lumbar spine; Lumbar Vertebrae - diagnostic imaging; Male; Middle Aged; Orthopedics; Osteoporosis; Vertebra; X-Ray Microtomography; μCT
• ISSN: 1529-9430; 1878-1632
• DOI: 10.1016/j.spinee.2015.06.059

Abstract Background context The ideal target of bone mineral density (BMD) measurements of the spine is the trabecula-rich vertebral body. Yet, spine BMD measurements routinely obtained with dual-energy X-ray absorptiometry also include the posterior elements of the vertebra, which are mainly cortical bone and insensitive to bone loss. Purpose We compared the bone mass of the vertebral body and posterior elements to determine the contributions of vertebral components to vertebral BMD measurements. Study design A micro-computed tomography study of lumbar vertebral bone. Methods From a spine archive, 144 cadaveric lumbar vertebrae (L1–L5) from 48 male human spines (mean age, 50 years) were scanned in air using micro-computed tomography to measure bone volume, bone mineral content (BMC) and BMD of the vertebral body, posterior elements, and entire vertebra. The contributions of the vertebral components to the total vertebral BMC and volume were compared, and the correlations between the BMC and BMD of the vertebrae and their components were examined. Results Overall, the vertebral body contributed about one-third of the total vertebral BMC and two-thirds of the total vertebral volume, and the posterior elements contributed the remainder. The vertebral body BMC and BMD were poorly correlated to those of the posterior elements (r=0.39 for BMC and r=0.34 for BMD, p