Abdominal adhesions are bands of fibrous scar tissue that form on organs in the abdomen, causing the organs to stick to one another or to the wall of the abdomen. In people living in developed countries, this scar tissue most commonly develops after abdominal surgery, in which organs are handled by the surgical team and are shifted temporarily from their normal positions. It can also form in people who develop peritonitis, an infection that has spread to the membrane that covers the abdominal organs. Peritonitis commonly occurs after appendicitis or another abdominal infection. Another cause of adhesions is endometriosis, an inflammatory condition that affects some women and may involve the abdomen and serious abdominal trauma.
In most patients, adhesions do not cause health problems. In a small number of people who have adhesions, however, the fibrous bands of scar tissue block the intestines either completely or partially. This blockage is called a bowel obstruction, and it leads to death in about 5% of cases. Sometimes, an area of intestine that is affected by adhesions can keep becoming blocked then unblocked, causing symptoms to come and go. In about 10% of small bowel obstructions, a portion of the bowel twists tightly around a band of adhesions. This cuts off the normal blood supply to the twisted bowel, causing what is called "strangulation," and that section of bowel begins to die. When this emergency happens, the person must be taken to surgery immediately. The death rate is as high as 37% in people who develop strangulation.
Adhesions are fairly rare in patients who have never had abdominal surgery. In people who have had multiple abdominal surgeries, adhesions are common.