Blunt or deceleration injury to the aorta is mostly confined to the thoracic aorta, except in the seat-belt injury, which involves the abdominal aorta. The radiologic evaluation must be as accurate as possible. Thoracotomy entails a significant risk, and a missed diagnosis is life threatening.
For this discussion, aortic rupture or disruption includes the aorta, the proximal portion of the great vessels, and the sinuses of Valsalva. The most common location for TAI is at the isthmus, just beyond the origins of the great vessels. In decreasing order of frequency, other locations are the descending thoracic aorta, the ascending aorta, the aortic arch, and the abdominal aorta. Ruptures at the aortic hiatus (diaphragm level) are less common. Competing theories of the mechanism of TAI have been proposed. Suffice it to say that the deceleration or crush forces interact with the asymmetric aortic fixation, causing translational and rotational forces that result in injury.
Pathologically, an aortic tear is usually transverse and involves the layers of the aorta to varying degrees. A complete tear through the intima, media, and adventitia usually leads to rapid exsanguination and death. In aortic rupture survivors, the pseudoaneurysm is contained by the adventitia and occasionally mediastinal structures.
Frequency:
In the US: Abdominal aortic TAI is extremely rare, with only 46 cases reported as of 1990.
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Excellent!
Since your source is not attributed I presume you can provide the statistics on aortal tears since 1990 in the decade when many secondary seatbelt laws were converted to primary seatbelt laws and also document the sudden increase in thoraxic aortal tears since these laws were passed and enforced.
Best regards,