Redefining the projectional and clinical anatomy of the duodenojejunal flexure in children.

The duodenojejunal flexure (DJF) is an important surgical landmark that enables the pediatric surgeon to establish whether normal intestinal rotation has occurred. The degree of variation in the position of the DJF has not been studied in the pediatric population, and there have been only limited studies on adults. The aim of the present study was to determine the position and relationships of the DJF in infants and children utilizing cross-sectional imaging. Computer tomography scans of 120 children were divided into three age groups and systematically analyzed. The DJF position was measured in relation to the vertebral body level, midline, anterior-posterior distance from the vertebral body, transpyloric plane, and mesenteric vessels. The position of the third part of the duodenum and the length of the mesenteric root were also determined. There was considerable variation in the DJF position with respect to the above landmarks in all three age groups. The vertebral body level of the DJF was centered on L1, but ranged between T11 and L3. In 3% of children with normal rotation the SMA/SMV relationship was abnormal. The third part of the duodenum was consistently found to be retromesenteric. The length of the mesenteric root ranged from 7 to 22 cm, and generally lengthened with increasing age. Owing to its variable position in infants and children, the DJF on its own may not be a reliable landmark for establishing normal intestinal rotation. Assessing for normal rotation is multifaceted and further comparative studies are required to characterize the anatomical features of normal and abnormal rotation.