Hernias are the most common cause of strangulation in patients presenting with small bowel obstruction.

BACKGROUND: Small bowel obstruction (SBO) is a leading cause of admission to surgical emergency units. Strangulation is associated with a 10-fold increase in mortality. The aim of the present study was to identify the most frequent causes of strangulation in patients presenting with small bowel obstruction.
METHODS: A prospective study was conducted of all patients presenting with SBO in one teaching hospital between 2003 and 2004.
RESULTS: One hundred and sixty-one patients with symptoms and signs of small bowel obstruction were admitted. Eighty-three were confirmed with contrast studies. The male:female ratio was 1:1.6. The aetiology of obstruction was adhesions in 97 patients (60.2%), hernia in 29 (18%), malignancy in 17 (10.6%) and miscellaneous causes in 18 (11.2%). Operative procedures were performed on 74 patients (46%), 31 of them (42%) with adhesions, 25 (34%) with hernias and 18 (24%) due to other causes. Strangulated bowel occurred in 15 patients (9.3%); 12 had hernias whilst three had adhesions (P < 0.0001). Of the strangulated hernias, ten were femoral, one was inguinal and one was paraumbilical. There were seven deaths; three occurred in patients declared unfit for surgery, while four occurred post-operatively - two had strangulated bowel, the other two had advanced cancer.
CONCLUSION: Whilst adhesions are the most common cause of small bowel obstruction, hernias remain the most frequent cause of strangulation in patients presenting with this condition.