Thursday, October 4, 2012

Arc of Buhler

The Arc of Buhler (or "Buhler's anastamotic artery") is an uncommonly encountered vascular channel linking the celiac system and the superior mesenteric system.  Normally, the two systems are connected through the gastroduodenal artery and pancreaticoduodenal arcade, and through the dorsal main pancreatic artery, but occasionally an embryonic anastomosis between the two persists, and can become an important collateral pathway for flow with stenosis of either artery.

The incidence of the Arc of Buhler ranges from 1-4% in the few studies investigating it, and its diameter has been assessed at 1.5 - 2.5 mm.

In these two images from a celiac axis arteriogram, the superior mesenteric artery fills through an enlarged vessel extending off the inferior aspect of the celiac trunk -- a hemodynamically significant Arc of Buhler.

The first image is a Terrarecon MIP image I made of the same patient from the celiac axis angiogram. It clearly shows the Arc of Buhler connecting the celiac and superior mesenteric arterial systems.  It also shows a proximal stenosis in the superior mesenteric artery (from atherosclerotic change), which likely contributes to the hemodynamic significance of the anastamosis.

On the second image, an explanation of how the anastomosis arises (ref 1)

Although noting its presence can be significant for preoperative planning or pre-TACE planning., aneurysms of the Arc of Buhler have also been reported, and treated with coil embolization.

Arc of Buhler aneurysm: top left axial CT image showing the presence of an aneusyms in the mesenteric vasculature; bottom left  MRA demonstrates that the aneurysm is separate from the gastroduodenal arcade, compatible with an Arc of Buhler aneurysm; right angiogram and coil embolization of the aneusym. (ref 2)

1. Saad WE, Davies MG, Sahler L, et al. "Arc of Buhler, incidence and Diameter in Asymptomatic Individuals" Vascular and Endovascular Surgery. 39:4 (2005) pp. 346-349
2. Dubel GJ, Ahn SO, Saeed MA. "Interventional Management of the Arc of Buhler Aneurysm" Seminars in Interventional Radiology. 24:1 (2007) pp. 76-81.