What is the most common cause of small bowel obstruction?

From the Guidelines

The most common cause of small bowel obstruction is adhesions, which account for approximately 60-75% of all small bowel obstructions. These adhesions are bands of scar tissue that form after abdominal surgery, and they can create kinks, twists, or narrowing in the small intestine, preventing the normal passage of intestinal contents 1. According to the most recent study published in 2021, adhesions were found to be the cause of the obstruction in approximately half of the reported cases of small bowel obstruction in patients with a virgin abdomen 1. Other significant causes of small bowel obstruction include:

• Hernias (10-20%)
• Malignancies (5-10%)
• Crohn's disease (5-10%) Less common causes include intussusception, volvulus, gallstone ileus, and foreign bodies. Patients typically present with abdominal pain, nausea, vomiting, abdominal distension, and constipation. Management depends on the severity and cause but may include bowel rest, nasogastric tube decompression, intravenous fluids, and possibly surgical intervention if the obstruction is complete or if there are signs of intestinal compromise. The World Society of Emergency Surgery (WSES) working group on ASBO has developed evidence-based guidelines to support clinical decision making in diagnosis and management of ASBO, which can also be applied to patients with small bowel obstruction in the virgin abdomen 1.

From the Research

Causes of Small Bowel Obstruction

• The most common cause of small bowel obstruction is postoperative adhesions, as stated in studies 2, 3, 4, 5, 6.
• Adhesions can form after any type of abdominal surgery and can lead to small bowel obstruction, which can be a life-threatening condition if not properly managed.

Risk Factors for Recurrence

• Studies have identified several risk factors for recurrence of adhesive postoperative small bowel obstruction, including:
  • Age <40 years 6
  • Adhesion or matted adhesion 6
  • Postoperative surgical complications 6
  • Number and sites of previous operations 6
  • Previous operation for adhesive postoperative SBO 6

Diagnosis and Management

• Diagnosis of small bowel obstruction is based on clinical evaluation, water-soluble contrast follow-through, and computed tomography scan 4.
• Non-operative management is recommended for patients with no signs of strangulation, peritonitis, or severe intestinal impairment 4.
• Open surgery is the preferred method for surgical treatment, but laparoscopy is gaining acceptance, especially in selected patients 4.