  Vertebral fractures prediction in clinics lacks of accuracy. The most used
scores have limitations in distinguishing between subjects at risk or not.
Finite element (FE) models generated from computed tomography (CT) of these
patients may improve the predictive capability. Many models have already been
proposed but the most of them considered the single vertebral body, excluding
from the analysis the role of the inter-vertebral discs in the distribution of
the load through the spine. Multi-vertebral models instead allow to examine
more complex boundary condition. However, CT scans do not provide
subject-specif information about the material properties of the disc.
Consequently, the goal of the study was to validate a multi-vertebral FE model
with subject specific modelling of the vertebral bone and population-based
properties assigned to the disc, idealizing them with a linear isotropic
material. Boundary condition were assigned in order to reproduce an
experimental test performed on the same specimen and recorded using digital
image correlation technique (DIC). FE and DIC strains on the vertebral surfaces
are compared point-wise. Young's modulus values in the range 25-30 MPa allowed
to achieve a comparable order of magnitude between experimental and
computational data. However, the two distribution remained strongly different.
To conclude, subject-specific material properties need to be assigned also to
the discs as well as to the vertebrae to achieve acceptable accuracy in the
assessment of the fracture risk.
