Stress distribution of vertebral fixation system screws

The emergence of pedicle screws has made it possible to perform more stable segmental instrumentation of the spine, which has now become the standard procedure for corrective surgery, stabilization of deformities and instability of the spine in thoracic, lumbar and sacral pathologies. This study used this technique to determine and analyze the internal stresses of photoelastic models under the influence of USS I pedicle screws when subjected to pull-out forces. To carry out the photoelastic analysis, 12 models were made and divided into three groups, each containing 4 photoelastic models. The first group, G1, consisted of a screw with an external diameter of 5 mm, the second, G2, consisted of a screw with an external diameter of 6 mm and the third, G3, consisted of a screw with an external diameter of 7 mm. The simulation was carried out using loads of 0.75 and 1.5 Kgf. The fringe orders were evaluated around the screws using the Tardy compensation method.

Pages: 112, Paperback, Our Knowledge Publishing