A finite element model of blunt traumatic aortic rupture

Blunt traumatic aortic rupture has a scene survival of 2-5% and is present in 20% of all automobile fatalities. The manner in which the forces from a range of thoracic impacts are transduced through the thoracic cavity to produce consistent injury to the aortic isthmus remains uncertain. Our objective was to create and evaluate a computer based finite element (FE) model of the aorta and observe its behavior during blunt traumatic impacts.

A finite element model of the thorax including details of the heart, aorta and pertinent thoracic structures was created and run under the FE code LS-DYNA3D. The motion response of the heart following a simulated thoracic impact was extracted from the thorax model and applied in a second more detailed model of the heart and aorta in order to investigate the stresses acting through the aortic isthmus during simulated thoracic impacts.

Simulated impact studies show that the predicted peak chest compression of the thorax model matched the measured responses from non-embalmed human cadaver impact studies by Kroell et al., 1974. The more detailed heart-aorta model predicted maximum stresses at the isthmus and pulmonary artery bifurcation the sites of most common trauma injury.

Analysis of the response of the finite element heart-aorta model during blunt thoracic trauma demonstrates its potential for predicting major vessel injury. The model will be helpful in the design of impact protection systems.