Defining Anastomotic Leak and the Clinical Relevance of Leaks.

Surgeons universally dread gastrointestinal anastomotic leaks, yet the precise definition is not widely agreed on despite international consensus guidelines. Likewise, leaks are not uniformly reported which makes comparisons across studies flawed. Leak rates range from 1 to 3% for ileocolonic, 0.5 to 18% for colorectal, and 5 to 19% for coloanal anastomoses. The sequelae of an anastomotic leak vary but generally correlate with the need for a change in clinical management, from minimal changes to the need for reoperation. Short- and long-term outcomes can be life-altering or life-threatening. Temporary or permanent stomas may be necessary and low pelvic anastomotic leaks may affect bowel function. For cancer patients, leaks can delay treatment and negatively affect oncologic outcomes. In Crohn's patients, leaks are associated with higher recurrence rates. In essence, the lack of agreement on the definition of an anastomotic leak inhibits meaningful understand of its epidemiology, prevention, and treatment.