In vitro full-field strain investigation in intact spine and spinal fixator by means of DIC

Spine is one of the most studied systems of the human skeleton because of the several types of problems that can injure it (accidents, pathologies, stresses). Many studies evaluated the range of motion, stiffness and strain on hard tissues under different loading conditions. To integrate the study with the deformation of the soft tissues (intervertebral discs and ligaments), Digital Image Correlation (DIC) can measure the distribution of deformation in a contact-less way and provide a full-field view of the examined surface under load. This study was performed using segment of human spine loaded in anterior bending with the use of loading machine and DIC. All tests showed the different deformation of the specimen in the vertebral body, intervertebral discs, ligaments and in the posterior rods. This work showed the feasibility and importance of investigating the spine in a full-field way, due to the high strain inhomogeneity in the vertebrae and intervertebral discs. Therefore it can give useful information to design medical devices and to surgeons to implant them.