Pressure aberrations inside the spinal canal during rear-end impact

Area of Science:

• Biomechanics
• Spinal Cord Injury Research
• Automotive Safety

Background:

• Minor soft tissue injuries of the cervical spine, often from low-speed rear-end collisions, can lead to long-term impairment.
• A leading hypothesis suggests pressure pulses in cervical fluid compartments during impact damage spinal nerve cell membranes.
• Previous animal and cadaver experiments support this injury hypothesis.

Purpose of the Study:

• To theoretically investigate pressure and flow pulses in cervical fluid compartments during low-speed (15 km/h) rear-end impacts.
• To develop and utilize a detailed 3D finite element model of the cervical spine and surrounding structures.
• To assess the potential for nerve cell damage by analyzing fluid dynamics and pressure changes.

Main Methods:

• Developed a 3D finite element (FE) model of the cervical spine (C1-T1), including vertebrae, discs, joints, ligaments, muscles, head, and a venous blood vessel.
• Incorporated fluid-structure interaction to accurately determine pressure behavior within the blood vessel.
• Calculated pressure pulses and associated shear stresses on the vessel wall during simulated rear-end impacts.

Main Results:

• Calculated pressure pulses showed qualitative agreement with reported measurements during the S-shape development phase.
• Shear stresses acting on the vessel wall were determined from the calculated flow pulses.
• Current analysis does not yet allow assessment of whether damage thresholds in the interstitial space are reached.

Conclusions:

• The finite element model successfully simulated pressure pulses in cervical fluid compartments during low-speed rear-end impacts.
• The study provides a foundation for further investigation into the biomechanics of cervical soft tissue injuries.
• Further research is needed to extrapolate findings to the interstitial space and assess nerve cell damage potential.