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

Abstract

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.

The Pattern of Injuries Among Motorcyclists in Fatal Road Traffic Accidents

“…14 Typically, the mechanism of injury to the aorta were due to frontal or side impact causing caudal or caudal-ventral thoracic load leading to aortic rupture. 14 One crucial factor at the helm of fatal motorcycle accidents was the concomitant use of substance while riding. 7,15,16 Findings in this study exhibited that fatalities occurring at night were three times more frequently to be under substance abuse than those during the day, which was similar to the statistics by the Department of Transportation of the United States.…”

Die traumatische Aortenruptur

“…Nur etwa 5-14 % der Betroffenen überleben zunächst am Unfallort und könnten potentiell ein Krankenhaus erreichen [4,8,13]. Die Gesamtletalität ist mit 94-98 % besonders hoch [6,8,13,14]. Da es sich zumeist nicht um isolierte Aortenverletzungen, sondern um Polytraumen handelt, sind die schnelle Diagnose und die optimale Behandlungsstrategie von größter Wichtigkeit.…”

“…In den meisten Fällen der Verkehrstoten mit Aortenruptur (loco typico) handelt es sich um ein stumpfes Thoraxtrauma mit seitlicher Gewalteinwirkung [8,[13][14][15][16]. Noch präziser könnte die Kraft von ventral oder ventro-caudal auf den Thorax einwirken [14,16]. Diese plötzliche Dezeleration führt zu einer starken intrathorakalen Kompression mit kranialer Verschiebung des Mediastinums [8,13,17].…”

“…Mehr als 2/3 der Autoinsassen, 90 % der Motorradfahrer und 70 % der Fußgänger und Radfahrer mit Aortenruptur erlebten ein Δv (Geschwindigkeitsdifferenz des Dezelerationstraumas, Aufprallgeschwindigkeit) >50 km/h. Bei einem Δv < 50 km/h erlitten 70 % der Motorradfahrer keine Aortenruptur [14]. In diesem Geschwindigkeitsbereich könnte also eine kritische Wirkungskraft liegen.…”

Finite Element Analysis of the Mechanism of Traumatic Aortic Rupture (TAR)

“…Researches from the American Association for Surgery of Trauma indicate that about 8000 victims die due to TAR each year [ 2 , 3 ]. Overall, TAR is responsible for up to 16% of automobile collision deaths [ 4 ]. Of the TAR victims, nearly 80% die on the scene of the accident, while 30% of those reaching hospitals alive, die within the next 24 hours [ 5 ].…”