The most common cause of small intestinal obstruction is:
Adhesion secondary to previous surgery are by far the most common cause for small bowel obstruction. Adhesions paicularly after pelvic surgery are responsible for more than 60% of cause of small bowel obstruction. Causes of small bowel obstruction in order of frequency: Adhesions (Approximately 60%) commonest Malignant tumors (approximately 20%) second most common cause. Most commonly these tumors are metastatic lesions. Hernias (Approximately 10%) Crohn's disease (approximately 5%) Ref: Sabiston 18/e, Page 1290.
Intussusception
Iatrogenic adhesion
Trauma
Carcinoma