Finite Element Analysis of Anterior Odontoid Screw Fixation for Type II Odontoid Fractures

TL;DR

This study uses computer simulations to analyze how well anterior screw fixation stabilizes type II odontoid fractures in the cervical spine.

Contribution

The study introduces a finite element method to evaluate the biomechanical effects of anterior screw fixation in type II odontoid fractures.

Findings

Screw fixation reduces vertebral displacement but increases stress and deformation compared to unfractured cases.

Posterior oblique loads cause the highest stress at the odontoid base and screw-bone interface.

Male patients show greater deformations and stresses under the same loading conditions.

Abstract

Introduction: Type II odontoid process fractures are common in the adult population, and anterior screw fixation aims to restore C1–C2 complex stability while preserving cervical motion. This study focuses on the numerical analysis of odontoid fractures, evaluating the structural behavior after anterior screw fixation using finite element simulations. Methods: Forty-eight patients (males, females, 74 years old on average) diagnosed with type II odontoid fractures and treated surgically between 2015 and 2023 were included in the study. Various loading conditions (magnitude and direction) were simulated to analyze displacements and stress distributions after screw insertion. Results: Screw fixation significantly fixes fractured vertebrae, but stress and deformation are considerably larger than in unfractured cases. Posterior oblique loads produced the highest stress concentrations, particularly at the base of the odontoid and the screw-bone interface. Male models exhibited greater total deformations and stresses under the same loading conditions, suggesting relevant biomechanical differences based on sex. Conclusions: Anterior odontoid screw fixation provides effective stabilization in type II odontoid fractures, although its performance depends on factors such as load vector and patient-specific anatomical characteristics. These findings support the use of FEM simulation as a valuable tool for personalized surgical analysis.

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