ROENTGEN EVALUATION OF ANOMALIES OF ROTATION AND FIXATION OF THE BOWEL IN CHILDREN.

Abstract

The radiologic signs are crucial for prompt diagnosis of anomalies of rotation and fixation of the midgut. With early identification of resulting complications, surgical therapy is usually life-saving. Numerous reports have covered the clinical aspects (7, 10, 13, 21, 27, 35, 37), but have not emphasized sufficiently the radiologic appearances. Recognition of these is less a matter of specialized tools and technics than of an understanding of the underlying mechanisms and common complications. This report is a presentation of the roentgenologic diagnostic approach, based on our experience and a review of 147 cases in children seen over a ten-year period at the Children's Hospital Medical Center of Boston (Table I). The radiologic findings are readily understood as disturbances of the phases of development of the gastrointestinal tract. Mall in 1898 (23) and Frazer and Robbins in 1915 (9) laid the foundations for Dott's classic article in 1923 (6) which showed the correlation between the embryology and the clinical features. A simplified and abbreviated version of the normal embryology is presented in Figure 1. Types of Anomalous Rotation Anomalies of bowel rotation must be understood in terms of disordered embryology. Interruption or aberrations of the orderly process of rotation and fixation may occur at any stage of development. In the rare extroversion of the cloaca (7), no rotation of the bowel has taken place and the ileum and colon each open separately onto the extroverted area in the midline, below the umbilical cord. Omphalocele (exomphalos) results from failure of the midgut to return from the umbilical cord. Lacking normal fixation, the small and large bowel have a common mesentery and usually maintain the primitive eighth fetal week relationship with only 90 degree rotation. As pointed out by Gross (13), 28 per cent of these cases require surgical correction of the malrotation. Four patients in our series, following repair of the omphalocele (Fig. 2), required surgery for bowel obstruction due to malrotation. Similarly, in infants with congenital left diaphragmatic hernia an associated anomaly of bowel rotation and/or fixation (Figs. 3, 5, 6) is always present. Gross recommends that malrotation and peritoneal bands be searched for and corrected when the diaphragmatic hernia is repaired. In 2 cases in our series a congenital right diaphragmatic hernia was associated with neurenteric canal and vertebral anomalies, and, in addition, one of these patients had esophageal and jejunal duplications. If the midgut returns to the abdomen too precipitously instead of gradually, beginning with the proximal jejunum, it will maintain the eighth fetal week relationship within the abdomen. The colon will lie in the left abdomen and the small bowel in the right, on either side of the superior mesenteric artery, with a common unattached mesentery.