ROSH Gastrointestinal Practice Exam

What is the most common risk factor for mechanical small bowel obstruction in the United States?

1. Abdominal hernia

2. Foreign body ingestion

3. History of gastrointestinal tract malignancy

4. Prior abdominal surgery

The correct answer is: Prior abdominal surgery

The most common risk factor for mechanical small bowel obstruction in the United States is a history of prior abdominal surgery. This is largely due to the formation of adhesions, which can develop as a result of surgical procedures. Adhesions are bands of scar tissue that can bind the intestines together or to the abdominal wall, leading to narrowing or twisting of the bowel, subsequently causing an obstruction. Prior surgical interventions, particularly those involving the abdomen, are prevalent and can contribute significantly to the incidence of obstructions. Adhesions can be asymptomatic at first and may develop years after the original surgery, making them a common and concerning complication. Other potential risk factors, such as abdominal hernias, foreign body ingestion, or history of gastrointestinal tract malignancy, can also lead to small bowel obstructions, but these are less frequent when considering the overall population. While hernias can certainly cause obstructions, they do not occur as frequently as adhesions related to previous surgeries. Foreign body ingestion is relatively uncommon, and malignancies, while they can cause obstructions, are less common than the adhesions formed from surgical history.