What is the Epidemiology of SMA Syndrome?

Discussion Superior mesenteric artery syndrome (SMAS) is caused by the compression of the superior mesenteric artery (SMA) against the 3rd part of the duodenum creating a proximal intestinal obstruction. It is relatively rare and can be hard to distinguish from other causes of intestinal obstruction. Normally the SMA arises from the anterior aorta around the L1 vertebra. It extends anteriorly and caudally into the mesentery of the small bowel. The angle between the SMA and aorta is called the aortomesenteric angle and is usually 38-65°. The distance between the SMA and aorta is usually 10-20 mm. Within the aortomesenteric angle lies the 3rd part of the duodenum and left renal artery along with a fat pad. The fat pad is felt to cushion the other organs and helps maintain the aortomesenteric angle. If the fat in this area is lost, then the angle decreases and compresses the duodenum and if the compression is severe enough then obstruction can occur. The left renal vein can also be compromised. In SMAS the angle is usually 6-25° and the distance between the SMA and aorta is 2-8 mm. Interestingly though, while most patients have a recognizable reason for the SMAS there are also a group of patients who have normal weight. SMAS can also occur after spinal surgeries where the spine is straightened. This causes increased tension on the mesentery and SMA, which again decreases the angle and therefore can cause duodenal compression and/or obstruction. SMAS usually presents wi...
Source: PediatricEducation.org - Category: Pediatrics Authors: Tags: Uncategorized Source Type: news