Digital model for surgical correction of scoliotic curvature of the spine in young children

Correction of congenital spinal deformities, including anomalies of vertebral formation, remains a key challenge in paediatric orthopaedics. Pathologies provoke biomechanical abnormalities of the spine, causing progressive curvature, restricted mobility, and pain syndrome. Ineffectiveness of conservative therapy requires surgical intervention, i.e., removal of abnormal structures, correction of deformity, and stabilization of the spine using a transpedicular spinal fixator. A critical factor in the success of surgery is preoperative planning, including the choice of fixator configuration. In recent years, digital models widely implemented in clinical practice have improved the accuracy of surgical planning through biomechanical analysis, allowing to predict implant behaviour and account for the patient’s anatomical features. The goal of the study is to develop a digital model of the biomechanical system comprising the vertebrae and the fixation implant to evaluate the stress-strain behaviour of spinal structures and fixation elements during surgery. A finite element model of the system with the vertebrae and the implant was developed based on computed tomography data from a patient diagnosed with scoliotic deformity with a 34° Cobb angle. Detailed analysis was carried out based on modelling for the stress distribution in bone tissue and the implant during corrective surgery of the deformity. The results show that stresses in bony structures are within acceptable thresholds. However, local plastic strains were detected in the contact zones between the rods and the screws. The results of the analysis can be used to optimize preoperative planning and enhance the reliability of implants used for treatment of spinal deformities in children.