Introduction and objectives: A novel fusionless epiphyseal staple aiming at treating pediatric scoliosis was developed by our research team, which necessitated lengthy and expensive experimental testing on animal models. The objective of this project was to develop a porcine spine numerical model as an alternative tool for the validation of our fusionless devices.
Methods: A parametric finite element model (FEM), including the epiphyseal growth plate, was developed using anatomical measurements of a porcine spine. The mechanical properties were taken from the literature or defined from calibration tests. The model was validated using experimental data. Vertebral growth modulation was programmed according to the “Hueter-Volkmann” principle, with a follower type load simulating physiological forces. Using a reverse approach, scoliosis induction was simulated using epiphyseal staples inserted over T5-T8 in the coronal plane. Three months of curve progression was simulated. Resulting Cobb angle and vertebral wedging were compared to longitudinal experimental data.
Results: The porcine spine model behavior was in agreement with reported flexibility data for flexion, extension, and lateral bending. Growth simulation resulted in a Cobb angle of 5.6° and local vertebral wedging of 3.4°, which was representative of an experimental scoliosis on pig spines similarly instrumented between T5-T8 over 3 months.
Conclusion: The results demonstrated the feasibility of the numerical model to realistically reproduce implant-restraining effects with adequate growth modulation. Ultimately, the developed model would serve for the design optimization of our novel fusionless staple, providing a time and cost effective numerical tool, before proceeding to further experimental surgeries on animals.
Acknowledgements: funded by NSERC (industrial research chair with Medtronic).