SMA syndrome / Wilkie’s syndrome / Cast syndrome / Mesenteric root syndrome / Chronic duodenal ileus and intermittent arterio-mesenteric occlusion.
* It is distinct from Nutcracker syndrome, which is the entrapment of the left renal vein between the Abdominal aorta and the SMA.
Superior mesenteric artery (SMA) syndrome is a very rare, life-threatening gastro–vascular disorder characterized by a compression of the third portion of the duodenum by the abdominal aorta (AA) and the overlying superior mesenteric artery. The syndrome is typically caused by an angle of 6°-25° between the AA and the SMA, in comparison to the normal range of 38°-56°, due to a lack of retroperitoneal and visceral fat. In addition, the aortomesenteric distance is 2-8 millimeters, as opposed to the typical 10-20.
Retroperitoneal fat and lymphatic tissue normally serve as a cushion for the duodenum, protecting it from compression by the SMA. SMA syndrome is thus triggered by any condition involving an insubstantial cushion and narrow mesenteric angle.