Gastrointestinal fistulae most frequently occur as complications after abdominal surgery (75-85%) although they can also occur spontaneously-for example, in patients with inflammatory bowel disease (IBD) such as diverticulitis or following radiation therapy. Abdominal trauma can also lead to fistula formation although this is rare. Postoperative gastrointestinal fistulae can occur after any abdominal procedure in which the gastrointestinal tract is manipulated. Regardless of the cause, leakage of intestinal juices initiates a cascade of events: localised infection, abscess formation and, as a result of a septic focus, fistulae formation. The nature of the underlying disease may also be important, with some studies showing that fistula formation is more frequent following surgery for cancer than for benign disease. Fistula formation can result in a number of serious or debilitating complications, ranging from disturbance of fluid and electrolyte balance to sepsis and even death. The patient will almost always suffer from severe discomfort and pain. They may also have psychological problems, including anxiety over the course of their disease, and a poor body image due to the malodorous drainage fluid. Postoperative fistula formation often results in prolonged hospitalisation, patient disability, and enormous cost. Therapy has improved over time with the introduction of parental nutrition, intensive postoperative care, and advanced surgical techniques, which has reduced mortality rates. However, the number of patients suffering from gastrointestinal fistulae has not declined substantially. This can partially be explained by the fact that with improved care, more complex surgery is being performed on patients with more advanced or complicated disease who are generally at higher risk. Therefore, gastrointestinal fistulae remain an important complication following gastrointestinal surgery.
