Finite Element Model-based Assessment of the Female Cervical Spine in a Rear-End Impact Simulation

One of the most common cervical injuries caused by car accidents is called whiplash injury or Whiplash-Associated Disorder (WAD). The WAD injury mechanism has had considerable effort towards its understanding, but it still not fully understood. Many studies in literature involve male subjects in rear-end whiplash simulations. However, there are few similar studies for female subjects. It is important to study the female cervical spine in whiplash simulations because more women than men suffer whiplash injury with a 1.5 to 2 times higher risk with women more frequently suffering long-term effects. The objective of this study was to develop a finite element method (FEM) model of the female cervical spine to conduct a model-based simulation of a rear-end whiplash-associated vehicular collision. This was accomplished by developing a high-fidelity FEM model of the female cervical based on subject-specific data, completing a model validation, and running a rear impact simulation on the FEM model. The validation showed that the model agreed with experimental corridors found in literature for ranges of motion (ROM) including flexion-extension, lateral bending, and axial rotation. A mesh and material sensitivity analysis were also conducted. Based on parameters found in literature, a rear impact simulation was performed. A pure moment was applied to C2 of the model to simulate the effects of the head on the cervical spine in a rear end car crash over 100 milliseconds. The hyperextension injury mechanism was investigated. It was found that in the lower vertebral segments, C4 through C7, the female model’s extension values exceeded those of a similar male model found in literature in 2 out of the 3 motion segments by a factor of 2 or more. The female model also greatly exceeded physiological values found in literature indicating a risk of hyperextension. It can be concluded that females are at a higher risk of hyperextension injury from whiplash-associated crashes than males under similar crash conditions.