Intestinal Malrotation and Volvulus

Abstract

Intestinal malrotation is a congenital abnormal position of the bowel within the peritoneal cavity secondary to an arrest of normal rotation of any part of the intestinal tract during the first trimester of embryonic development. Malrotation is accompanied by abnormal bowel fixation, resulting in a narrow-based attachment of the mesentery and the presence of abnormal peritoneal bands (Ladd’s bands). These abnormalities lead to increased risks of bowel obstruction and midgut volvulus. Malrotation with volvulus is a true life-threatening emergency; delayed diagnosis can lead to necrosis of the midgut.

Most patients present with bilious vomiting and signs of obstruction in the neonatal period. Plain radiographs, demonstrating proximal small bowel obstruction, are always nonspecific. Contrast enema and upper GI series allow to define intestinal anatomy and to diagnose malrotation and volvulus. Upper GI series defines the position of the duodenojejunal junction, which is normally located to the left of the spine at the level of the duodenal bulb on frontal view. Any other position of the duodenojejunal junction (DDJ) would be considered malrotation of the gut. Upper GI series may also depict a Z-shaped duodenum in the presence of obstructing peritoneal bands or a duodenojejunal corkscrew twist in the presence of volvulus. Contrast enema determines the position of the cecum. Ultrasound, once proposed for the screening of malrotation on the basis of relative relationship of mesenteric vessels, is valuable in identifying acute volvulus, as it easily depicts signs of bowel obstruction and identifies specific signs of volvulus, such as the twisting of mesenteric vessels.