Biomechanical modelling of surgical reconstructive treatment of spinal spondylolisthesis at L4-L5 level

Spondylolisthesis is a displacement of the overlying vertebra relative to the underlying vertebra. Modern medicine applies decompression and stabilization of the damaged spinal segment when performing surgical reconstructive treatment of spondylolisthesis. For these purposes, transpedicular fixators are used together with intervertebral disk substitutes. It is possible to install the fixation system without degenerative disk replacement. The choice of fixation and instrumentation type depends on patient's clinical data, experience and preferences of the surgeon. At the same time, there is a problem of choosing and justifying the choice of surgical reconstructive treatment of spinal spondylolisthesis. In this work, a biomechanical study of three variants of surgical reconstructive treatment with installation of transpedicular fixators was performed: without replacement of a disk, with a disk substitute of Mesh cage and Pezo-A substitute. The developed biomechanical criteria of surgical reconstructive treatment of diseases and spinal injuries were used when analyzing the results of modelling and justifying the choice of the most rational treatment variant. Results showed that from biomechanics point of view the most rational were two treatment variants, implying the installation of transpedicular screws and intervertebral disc substitutes Mesh or Pezo-A. In accordance with biomechanical criteria for the success of surgical treatment, none of these options has significant advantages. Therefore, the final choice of the treatment variant should be made based on medical data of individual patient and personal experience of surgeon. It should be noted that variant without replacing the damaged intervertebral disc is the least preferred.