Finite element analysis of cervicomedullary stress and strain in atlas orthogonal correction using radiographic rotational inputs: A multi-case study.

OBJECTIVES

The biomechanical effects of radiographically guided atlas-axis correction at the craniocervical junction remain insufficiently quantified, particularly at the tissue level. Therefore, this study aims to investigate the relationship between rotational alignment correction and cervicomedullary stress-strain response using a finite-element approach.

METHODS

A total of four retrospective clinical cases with pre- and post-correction radiographs were analyzed. Radiographic parameters, including axial spinous process rotation, atlas frontal plane, and cervical spine angle, were used as kinematic inputs in a validated three-dimensional finite-element model of the cervical spine (C0-C7). Simulations were performed under quasi-static conditions to evaluate spinal cord stress, strain, and ligament deformation.

RESULTS

Analysis showed that alignment correction resulted in consistent reductions in spinal cord stress (15-35%) and strain (18-40%) across all cases. Larger rotational corrections were associated with greater biomechanical improvements. In addition, ligament strain values remained within safe physiological limits (approximately 25-45% of failure thresholds), indicating no excessive loading of stabilizing structures.

CONCLUSIONS

This study demonstrates that radiographically guided alignment correction is associated with reduced cervicomedullary mechanical loading. The findings provide biomechanical insight into the relationship between rotational alignment and tissue-level response. However, the results should be interpreted as computational trends rather than clinical outcomes, and further studies with larger datasets and subject-specific models are required.