Injury Mechanisms of Aortic Ruptures to Vehicle Occupants and Vulnerable Road Users – An In-Depth-Investigation over Time

Dietmar Otte, Thorsten Facius and Stephan Brand

A rupture of the aorta was a common injury observed in the 60ies and 70ies regarding unprotected car occupants, reported in 10% to 15% of vehicle mortalities in the past. With this study it is investigated how often the Aortic Rupture can be observed in today´s traffic accident scene and what changes happened in the course of time history regarding different kinds of traffic participation and different kinds of injury mechanisms. Based on very well documented in-depth-accident cases by GIDAS (German-In-Depth-Accident-Study) a representative sample of all traffic accidents during a 40 year period (years 1973 to 2014) is available (n>100.000 involved persons) and the cases with Aortic ruptures AR (n=142) are analyzed in detail.
The Aortic rupture can be observed in high speed accidents with high body deceleration and direct load to the thorax. Nearly always a high compression of the thorax is responsible for the load direction to the heart vessel. The analysis found load in most cases from caudal-ventral in 26.1% and from ventral 21.1%. Another high percentage could be registered from the left and the right (19.7% each) and 7.5% in roll-over events by vehicles with high thorax compression. The rupture was found mostly classical on the area of the aortic arch into pars descendens caused by a kind of scoop-mechanism and in few cases a hyper flexion mechanism, but never with deceleration effect only. Today the AR is very seldom registered for car occupants (0.1%) and also for cyclists (0.05%), more frequent for pedestrians (0.22%) and motorcyclists (0.23%). Related in the course of time history the focus of AR has to change from car occupants to vulnerable road users. Always the characteristic is linked with high thorax deformation mainly in accident situations under high impact speed, no seatbelt and direct body impact.