External duodenal fistula is a rare condition. Two forms of fistula have been described; namely, an external and an internal duodenal fistula. External duodenal fistula is more frequent than is internal fistula. Internal duodenal fistula may occur between the duodenum and other abdominal viscera, as, for example, between the duodenum and the gallbladder. A number of cases of so-called internal duodenal fistula have been reported in which there was a rupture of the duodenum. These cases of rupture of the duodenum, which are not true fistula, were caused by indirect violence inflicted on the abdomen, such as a kick from a horse, a fall, or a blow by being struck by a golf ball.
External duodenal fistula is usually caused by injury to the duodenum during the performance of surgical operations in the right upper part of the abdomen. Injury to the duodenum may occur during operation on the duodenum,