What are abdominal adhesions and why do they form?
Abdominal adhesions are important because they are a common cause of abdominal symptoms, particularly abdominal pain and they can cause bowel blockages or obstruction. The term adhesions refers to the formation of scar tissue between bowel loops (small or large intestine) and the inner lining of the abdominal wall (peritoneal lining) or with other organs within the abdominal cavity (liver, gallbladder, uterus and its attached Fallopian tubes and ovaries, and urinary bladder). Adhesions can also form between loops of the small and large intestine.
Adhesions form when inflammation occurs on the surface of the abdominal organs or the peritoneal lining of the abdominal cavity; the formation of scar tissue is a normal part of healing when there is inflammation. The cause of the inflammation can vary considerably. It may be due to inflammation of an organ (for example, cholecystitis, appendicitis), prior surgery in which organs or the peritoneal lining are cut, inflammation of the peritoneal lining of the abdomen (peritonitis), or abdominal radiation treatment. Other causes of inflammation and scarring include:
- handling of abdominal organs at the time of surgery,
- foreign objects left inside the abdomen at the time of surgery (for example, a piece of gauze),
- bleeding into the peritoneal cavity, and
- gynecological conditions (for example, pelvic inflammatory disease).
Under normal conditions, the loops of the small and large intestines are free to move around within the abdominal cavity, sliding over each other and the surrounding organs over a thin film of lubricating fluid. When adhesions form, the intestines are no longer able to move around freely because they become tethered to each other, the abdominal wall or to other abdominal organs. At the sites where adhesions occur, the intestine can twist on itself, and the twisting may obstruct the blood supply or the normal movement of its contents, particularly in the small intestine. Most of the time the twisting is intermittent, but occasionally the twisting does not reverse spontaneously. The symptoms from adhesions may occur soon after the inflammatory process sets in; however, more typically they occur several months or even many years later.
What are the symptoms of abdominal adhesions?
Although abdominal pain and other symptoms of intestinal obstruction are by far the most common effect of adhesions, another important consequence is infertility in women. The infertility is believed to be caused by adhesions involving the Fallopian tubes that results in kinking and obstruction, thereby preventing the eggs that are released from the ovary from reaching the uterus.
Symptoms caused by adhesions may vary from specific (typical) to non-specific. When the symptoms are typical, the diagnosis is easy since adhesions are the most common cause of intestinal obstruction.
The typical symptoms of obstruction are abdominal discomfort located around the belly button (umbilicus) that is cramp-like, followed by distention of the abdomen. Symptoms often are worsened by eating. There may be reduction in the amount of flatus (gas) or stool that is passed and, with prolonged obstruction, nausea and vomiting may occur. When the obstruction is incomplete or intermittent, symptoms may be less severe with abdominal pain or cramping occurring only after meals. Although uncommon, obstruction also may manifest primarily as nausea with or without vomiting, especially when the obstruction occurs in the proximal small intestine near the stomach. It is important to remember, however, that most adhesions do not cause symptoms.
How are abdominal adhesions diagnosed?
There are no tests that can clearly identify adhesions, but the pattern of obstruction often can be recognized on plain X-ray films of the abdomen by the presence of dilated loops of small intestine. Contrast X-rays of the small intestine, specifically the use of small bowel follow through examination, may show abnormal angulation of the intestinal loops that suggest the presence of adhesions. Such a finding, however, does not mean that the adhesions necessarily are responsible for the symptoms. Other tests such as ultrasonography and computerized tomography (CT) are often necessary, primarily to exclude other causes of obstruction, for example, tumors and strictures (bowel narrowing).
How are abdominal adhesions treated?
The treatment of adhesions is straight-forward. Patients undergo either laparoscopic or open surgery and the adhesions are cut by scalpel or electrical current (lysis). The problem is that adhesions have a tendency to reform, and some individuals have a propensity to form adhesions. Laparoscopic surgery results in fewer adhesions and, theoretically, is a better option; however, whether the adhesions are lysed at laparoscopic or open surgery, the inflammation caused by the process of cutting can result in recurrent adhesions.
Adhesions due to open surgery can be prevented by the use of a product called Seprafilm. Seprafilm is a waxed paper-like film that is placed inside of the abdomen over the intestines. The film covers the intestine and keeps them from sticking to the incision from sticking to the incision. The incision heals normally with scarring, but the film prevents the scar tissue from spreading to the adjacent tissues to form adhesions. After several days, the film dissolves spontaneously. Seprafilm should be carefully placed because it can slow down the healing (scarring) process. For example, if the film is wrapped around an incision in a hollow organ such as the intestine, the incision may not heal, and a leak from the organ may occur.
Medically reviewed by John A. Daller, MD; American Board of Surgery with subspecialty certification in surgical critical care
Postoperative Adhesions: From Formation to Prevention: Pathophysiology.