Article

Trabecular bone strength diminishes as a result of osteoporosis and
altered biomechanical loading at the vertebral and spinal levels. The spine
consists of the anterior, middle and posterior columns and the load supported by
the anterior and middle columns will differ across different regions of the
spine. Stress shielding of the anterior column can contribute to bone loss and
increase the risk of wedge fracture. There is a lack of quantitative data related
to regional spinal bone mineral density distribution over time. We hypothesize
that there is an increase in the posterior-to-anterior vertebral body bone
mineral density ratio and a decrease in whole-body bone mineral density over
time. METHODS: Bone mineral density was measured in 33 subjects using
quantitative computed tomography scans for L1-L3 vertebrae, region (anterior and
posterior vertebral body), and time (baseline and 6 years after). FINDINGS:
Lumbar bone mineral density decreased significantly (Delta: ~15%) from baseline
to the 6th year visit. Individual vertebra differences over time (L1: ~14%, L2:
~14%, L3: ~17%) showed statistical significance. Anterior bone mineral density
change was significantly greater than in the posterior vertebral body region
(Delta anterior: ~18%; Delta posterior: ~13%). Posterior-to-anterior bone mineral
density ratio was significantly greater in the 6th year compared to baseline
values (mean (SD), 1.33 (0.2) vs. 1.23 (0.1)). INTERPRETATION: This study
provides longitudinal quantitative measurement of bone mineral density in
vertebrae as well as regional changes in the anterior and posterior regions.
Understanding bone mineral density distribution over time may help to decrease
the risk of wedge fractures if interventions can be developed to bring spine
loading to its normal state.
CI - Copyright (c) 2012 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS