Radiologic findings of retroperitoneal perforation after sphincterotomy.

The radiographs of all patients with perforation into the retroperitoneum following endoscopic sphincterotomy, performed between 1981 to 1984 at University Hospital, London, Ontario were reviewed retrospectively. The incidence of perforation was very low. There were only three patients with perforation (1.1%), although 264 sphincterotomies had been performed. The initial and most important radiological findings are air and contrast medium in the retroperitoneum outlining the right kidney; a mottled air and soft tissue density in the right anterior pararenal space due to leak of duodenal contents, bile and air; or both of these findings together. With ultrasonography, a right paranephric fluid collection or an inflammatory mass adjacent to the right kidney or both may be better visualized. Computed tomography, the definitive study, delineates the true extent of the fluid or mass in the anterior pararenal space. Early detection by the radiologist is mandatory to minimize morbidity. To make this diagnosis early requires a high index of suspicion when reviewing the abdominal radiographs of those patients with pain during, or a few hours after, sphincterotomy.