Background: Approximately 3,000 bariatric operations are performed in Norway annually. Laparoscopic gastric bypass is the most widely used procedure. Internal hernia is a potentially serious cause of acute abdominal pain after a gastric bypass.
Material and method: The review is based on a discretionary selection of articles found in PubMed coupled with the authors' personal clinical experience.
Results: Internal hernias due to protrusion of the bowel through mesenterial defects, or slits, occur in approximately 0-10% of patients after a gastric bypass. The incidence depends on follow-up time, surgical technique and whether the mesenterial slits were closed during the operation. The pain may be acute, intense and prolonged, with nausea and vomiting, or intermittent, following food intake. Cases of acute pain may be due to obstruction of and reduced blood circulation to the bowel, and require an emergency operation. A CT scan may reveal or arouse suspicion of an obstruction, but cannot rule it out. Pregnancy is a risk factor, and fertile women should be informed of this. Many recommend closure of mesenterial slits during the primary operation to reduce the risk of hernia.
Interpretation: Internal hernia after a gastric bypass is a potentially serious and not uncommon complication requiring rapid surgical intervention. All departments with preparedness for emergency abdominal surgery should be aware of this condition.