Optimization of transpedicular spondylosynthesis application for type A3 lesions of the thoracolumbar transition: clinical experimental study

Objective: the optimization of transpedicular systems application for type A3 lesions of the thoracolumbar transition using computer simulation based on the fnite elements method. Material and Methods. The examination data (post-traumatic kyphotic deformation, intensity of pain syndrome, length of operation and extent of blood loss) of 81 prospectively enrolled male patients who in 2017-2018 had been operated for Th11-L2 vertebrae simple fractures of А3N0M1 type (AOSpine classifcation). The patients were divided into 3 groups in accordance with the type of intervention performed on them: short-segment (n=42), 8-screws polysegment (n=25) and 6-screws polysegment (n=14). Biomechanical simulation based on the computer tomography data was performed for each variant of the metal construction arrangement. Results. In the process of biomechanical simulation with all the variants of the instrumented spine 3D-models loading 8-screws construction proved to be the most consistent one, at that the stability of polysegmental constructions exceeds that of bisegmental one by an order. The results of surgical management were evaluated in terms of up to a year following the intervention. The loss was less and the correction worked better with polysegmental fxation despite more complicated initial conditions for the correction compared to those of group 1 Conclusion. Biomechanical simulation shows prerequisites for the development of bisegmental systems instability as the equivalent stresses and peak displacements are higher compared to those of polysegmental fxation. The efciency analysis of application of various transpedicular fxations for type A3 thoracolumbar transition lesions attests to the advantage of polysegmental arrangements of transpedicular systems, at that the implantation of the 6- screws polysegmental system should be considered the frst choice on the number of indices.