Biomechanics of the spine in fracture of the spine before and after surgical treatment. Biomechanical experiment

The work is devoted to the study of the biomechanical behavior of the segment of the thoracic spine with a comminuted compression fracture of the Th11 vertebral body, as well as with various options for fixing the injured spinal motion segment (SMS). The following fixation options were considered: short-segment transpedicular system (TPS); short-segment TPS, supplemented with an intermediate screw inserted into the damaged vertebra; short-segment TPS, supplemented with intermediate screws inserted into the damaged vertebra. Models of spinal segments with damage to the vertebral body are built on the basis of patient computed tomography data in Mimics Materialize, 3-Matic Materialize and SolidWorks software. Models of fixing elements, as well as their introduction into the model of the spine segment, are performed in SolidWorks. The materials assigned to the models were considered linear, elastic, isotropic. The boundary conditions and loading of the models are performed in the FEP ANSYS 19.2. The loading of the models corresponded to the position of a person standing, flexion, extension, lateral bending and axial rotation. The numerical solution of the problem of the theory of elasticity was carried out in the FEP ANSYS. The field of total displacements in the models, equivalent stresses von Mises in fixing structures and vertebrae were calculated. The range of motion was measured in the spinal motion segment, including the damaged vertebra. Revealed a redistribution of equivalent stresses von Mises, which reduces the load on the injured vertebra, as well as a decrease in the mobility of the injured vertebra when installing the TPS, supplemented with an intermediate screw, regardless of the side of its installation.