Bs. Myers et al., IMPROVED ASSESSMENT OF LUMBAR VERTEBRAL BODY STRENGTH USING SUPINE LATERAL DUAL-ENERGY X-RAY ABSORPTIOMETRY, Journal of bone and mineral research, 9(5), 1994, pp. 687-693
Clinical and biomechanical investigations indicate that assessment of
vertebral body bone mineral density (BMD) by anteroposterior dual-ener
gy x-ray absorptiometry (DXA) is a useful index of vertebral body stre
ngth and fracture risk in osteoporosis. However, inclusion of non-forc
e-bearing and small-force-bearing mineralized structures, such as the
posterior elements and aortic calcifications, in the measurement of an
terior BMD obscures the assessment of vertebral body mass by this tech
nique, Indeed, such interference is particularly severe in the presenc
e of posterior element degeneration or previous spinal surgery. Recent
anatomic studies illustrate that the lateral view provides unobstruct
ed visualization of the L3, L4, and possibly L2 vertebral bodies, sugg
esting that supine lateral BMD may more accurately assess vertebral bo
dy fracture risk, We evaluated this hypothesis in a blinded study usin
g human cadaver spines to compare the value of supine lateral and ante
roposterior BMD in assessing vertebral body fracture force, average co
mpressive stress, maximum stored strain energy, and strain at failure.
Both measures of BMD significantly correlate with these biomechanical
measures. However, statistical comparison of the methods using multip
le and stepwise regression reveals that supine lateral BMD provides a
better assessment of the vertebral body fracture properties than anter
oposterior BMD. The enhanced predictive value of supine lateral BMD oc
curs because of the variable contribution of posterior element mineral
to the anteroposterior BMD measurement. Evaluation to test the utilit
y of supine lateral BMD for the assessment of fracture risk and a frac
ture threshold in patients with osteoporosis is therefore recommended.