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Sat May 3 15:43:40 BST 2008

While looking at the location please look at the beginning of the fibrous encasement if the aorta. It seems anatomically that the shear forces should be greatest where the arch is relatively free and where it becomes bound by fibrous tissue to the vertibral bodies. This portion should have more shear in a smaller area and more circumfrential distribution than the isolated attachment of the ligament. Therefore complete tears vs only a plug pulled out of the aorta

Norman
Typed by the thumbs of
Norman on his BlackBerry 

Norman McSwain, MD
Tulane Univ Surgery
504 988-5111

----- Original Message -----
From: trauma-list-bounces at trauma.org <trauma-list-bounces at trauma.org>
To: trauma-list at trauma.org <trauma-list at trauma.org>
Sent: Sat May 03 08:26:12 2008
Subject: Re: Aorta: Transection vs. Dissection.....location, location,location

Dr. Hronek,
This is one of the major differences I have encountered between the initial
survivors of aortic injury reported in the literature and the fatal cases
(which includes some initial survivors) included in my research.   So far,
out of the ~300 or so cases I have looked at (I actually have the reports
for ~500 cases, but have not had a chance to look at all of them yet), I
have noticed that there are two exceedingly common sites for the aortic
injury being described amongst the decendents.  The first, and most proximal
tends to be partial or complete transection within a centimeter or two of
the aortic valve.  The other- the more classic- is near the ligamentum
arteriosum.  There have also been a couple of other interesting vascular
injuries encountered including bilateral blunt disruption of the carotids,
but injuries to the aorta have been an area of special focus, since it was a
debate regarding risk factors for them that first provided the kick in the
butt to get going with this project.

I don't have the database readily at hand at the moment (since I am at
work),  but I would say that about 30% of the injuries are in the ascending
aorta, 50% are at or within 2 centimeters of the ligamentum and the remain
20% are of an unspecified location or are in the distal thoracic aorta.  As
I said, these are rough guesses and the more accurate numbers should be
published some time next year.  I am simply waiting to complete the initial
goal of 1500 cases before I commit anything to paper for publication.

The rates of injury you quoted have raised my desire to consider looking at
if there is any difference in those victims who survive to hospital
admission and then die, versus those who die on impact or shortly
thereafter.

> ------------------------------
>
> Message: 7
> Date: Fri, 2 May 2008 22:51:16 -0700 (PDT)
> From: Ivan Hronek <ivanhronek at yahoo.com>
> Subject: Aorta: dissection vs. transection
> To: trauma-list at trauma.org
> Message-ID: <107420.78518.qm at web62310.mail.re1.yahoo.com>
> Content-Type: text/plain; charset=iso-8859-1
>
> Ian, I agree that in trauma survivors a lesion at the level of the takeoff
> of the left subclavian artery is much more common then an ascending aortic
> injury:
>
> At the point of the greatest shearing force, the isthmus of the aorta, 95%
> of injuries are found; only 5% are detected in the ascending aorta. At the
> point of the greatest shearing force, the isthmus of the aorta, 95% of
> injuries are found; only 5% are detected in the ascending aorta.
> http://www.mdconsult.com/das/article/body/93775974-2/jorg=journal&source=&sp=984672&sid=0/N/47574/1.html?issn=0749-0704#H073308
>
> ________________________________
>
>
> http://radiology.rsnajnls.org/cgi/reprint/209/2/335
> In patients who survive long enough toreach the hospital, the most
> commonlocations of ATAIs are the aortic isthmus(in 80%-90% of patients), the
> ascending
> aorta (in 5-9%), and the diaphragmatic
> aorta (in 1%-3%) (4-6,19,26,49,63-71).Multiple aortic lacerations or
> concomi
> aontic branch vessel injuries occur in
> 6%-20%
> (2-4,7,8,56,64,72-82).In autopsy
> series (2,3,6-8,17,19,63,64,66,80,83,84),
> up to 22% of ATAIs are in the ascending
> aorta, death having been immediate and
> commonly associated with severe cardiactantand 4%-10% of cases,
> respectivelyinjuries (in 80% of cases), including pericardialtamponade,
> aortic valve tear, myocardialcontusion, and coronary artery injury.
>
> ________________________________
>
> However, the difference between the two entities has to do more with the
> etiology of the injury and the actual lesion can be similar: in both
> situations there is initially a tear/laceration of the aortic wall. This can
> then lead to a dissection(=longitudinal tear), transection(=circular tear),
> aortic intramural hematoma, pseudoaneurysm, periaortic hematoma, contained
> rupture etc. During the development of these steps the pathology on TEE can
> be similar - existence of true and false lumens, pulsations towards the
> false lumen, a jet at the point of entry of the blood, communicating or
> noncommunicating additional lumen etc.etc:
>
>
>
> Transection of proximal distal thoracicaorta adjacent to the isthmus.
>
> ________________________________
>
>
>
>
> Left, aortic dissection with intimal flapand entry site of distal thoracic
> aorta;
> Right, aortic dissectionrenal flow via color flow Doppler through intimal
> tear.
> TL,true lumen; FL, false lumen.
>
>
> ________________________________
>
>
>
> Ivan Hronek MD
> Los Angeles, CA
>
>
> ________________________________
>
> >
> > --
> > Stephen L. Richey, CRT
> > Aviation Injury Research Project Leader
> > Saginaw Valley State University
> > Phone: 248-366-4452
> >
> >
> >
> > "You should never put off for tomorrow what you can do tonight, because
> > you never know what is going to come in tomorrow."- Robert A. Fink, MD, FACS
> >
>
>
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Aorta: Transection vs. Dissection.....location, location, location