Redundant Duodenum: A Roentgenologic Study

MUCH has been written in recent years on duodenal anomalies. The roentgen-ray examination offers a reliable method for a thorough investigation of the duodenum. Abnormalities of this portion of the small bowel are frequently overlooked, principally because of the fact that the examiner concentrates his attention on the first part of the duodenum. It is quite probable that were the entire duodenum studied with the same meticulous care, many more instances would be discovered. Anomalies of the duodenum are far more common than is indicated by a survey of the literature. Of these, the redundant duodenum is of especial interest. It is a condition in which there is usually an elongation of the superior portion of the duodenum with a ptosis of the mid-portion of the superior segment resulting in an anomalous loop. Recently (1,2) we have called attention to this malformation and its clinical significance, and have established this anomaly as a roentgenologic entity. The normal duodenum, about 27 cm. in length, has a definite anatomic configuration in the form of a “C,” or incomplete circle. In this anomaly the superior aspect of the duodenum is lengthened. The duodenum lends itself easily for roentgen examination, and any abnormality may readily be disclosed by this method of investigation. The duodenal cap or first portion of the duodenum which normally represents the superior duodenum is surmounted upon the pyloric outlet. It is about 5 cm. in length and presents itself in the form of a cone, with its base at the pylorus and apex forming the first duodenal angle. From the apex, the duodenum as a rule makes a sudden drop and is usually directed to the right of the cap and somewhat posteriorly. It is held in place by the hepato-duodenal ligament, which represents the free margin of the lesser omentum. In the redundant duodenum the normal configuration is quite altered because of the marked elongation of the superior segment. Any portion of the duodenum may be involved, but this malformation is more commonly found in the superior part. Since the superior duodenum is lengthened, another angle is formed to the right of and posterior to the first angle, which is held in place by the hepato-colic ligament. The distance between the two angulations varies according to the length of the superior duodenum and the size of the ptosed loop. The elongated portion of the superior duodenum varies in length from 5 to 10 cm., which measurement is exclusive of the bulb. In some instances sharp angulations may exist, but no instances of prolapse of the angles were observed in this study. The resultant picture, as viewed roentgenologically, is a deformity of the superior segment, forming a water-trap effect in which the flow of the contrast meal through the duodenum is delayed. The incidence of this anomaly in the routine gastro-intestinal roentgen examination is rather small, occurring in about 2.5 per cent in our series of cases.