A 56-year-old man has had generalized abdominal pain for the past three days that has gradually worsened. He has not had flatus during the past two days. Upright abdominal X-ray suggests a small bowel obstruction. History of which risk factor is the most common for the development of this disease?

• A. Smoking
• B. High-fat diet
• C. Alcohol use
• D. Prior Abd Surgery

Answer: (D)

Adhesions from prior abdominal surgery are the most common cause of small bowel obstruction in adults. When the abdomen heals after surgery, fibrous bands can form and tether or kink loops of bowel, repeatedly narrowing or blocking the lumen and leading to obstruction. Because these adhesions are the leading cause, a history of prior abdominal surgery is the strongest risk factor for developing an SBO. Other factors listed—smoking, a high-fat diet, or alcohol use—don’t predispose to mechanical obstruction of the small bowel and are associated with different GI problems, not SBO.