azygous vein
Posted: Tue Sep 04, 2012 10:04 am
http://ats.ctsnetjournals.org/cgi/conte ... /60/5/1294
I think we wonder as patients exactly how the azygous vein is involved in cerebrospinal drainage. I originally two years ago thought it drained the spine, but that is an oversimplification. The azygous vein despite being in the chest is also involved in draining the brain. You can infer this because there is a major route for retrograde perfusion to follow from the azygous to the brain.
Sometimes retrograde perfusion is used medically to get oxygen to the brain while a procedure or surgery is done somewhere in the body that blocks flow in the usual direction. Here it mentions operation on the aortic arch as a situation where the doctor would use retrograde cerebral perfusion.Retrograde cerebral perfusion: anatomic study of the distribution of blood to the brain
MD Jean-Louis de Brux*, MD Jean-Baptiste Subayi, MD Jean-Dominique Pegis, MD Jean Pillet
Background.: Despite apparently good clinical results with retrograde cerebral perfusion during operation on the aortic arch, there is still concern about the real distribution of the blood injected in the superior vena cava to the brain, especially when the internal jugular vein is valvulated (88% of the cases). This anatomic study was carried out to determine how a liquid injected in the superior vena cava reaches the brain.
Methods.: Three groups of adult cadavers (5, 5, and 3 cases, respectively) were injected with latex, colored blue, through a cannula in the superior vena cava. In group I, 600 mL of latex was injected. Group II was identical except that a catheter had been inserted, before the injection, into the internal jugular vein to collapse the internal jugular vein valve, when existing. In group III, the azygos vein was ligated.
Results.: The internal jugular vein was not valvulated in 2 cases in group I. In those 2 cases, latex was found up to the jugular foramen. In the other cases in group I, and in all cases in group II, where the internal jugular vein was valvulated, the following veins were injected: internal jugular vein up to the valve (almost no latex beyond), azygos vein, inferior vena cava, renal veins, rachidian and perimedullar venous plexuses, and venous sinuses of the brain. In group III, no opacification was observed beyond ligated azygos vein or valvulated internal jugular vein.
Conclusions.: Despite the fact that this study was carried out on cadavers, one can assume that, during retrograde cerebral perfusion, the azygos vein system is a major way to the central nervous system when the internal jugular vein is valvulated.
I think we wonder as patients exactly how the azygous vein is involved in cerebrospinal drainage. I originally two years ago thought it drained the spine, but that is an oversimplification. The azygous vein despite being in the chest is also involved in draining the brain. You can infer this because there is a major route for retrograde perfusion to follow from the azygous to the brain.