Incarcerated Hernia

An incarcerated hernia is a hernia whose contents cannot be reduced back into the abdominal cavity.

Incarceration does not automatically mean the bowel is ischaemic.

The distinction from strangulation is critical:

Incarceration means irreducibility.

Strangulation means compromised blood supply.

An incarcerated hernia can cause mechanical bowel obstruction and may subsequently progress to strangulation.

The hernia becomes persistently irreducible and is often painful or tender.

If bowel is trapped, the patient may develop colicky pain, vomiting, abdominal distension and reduced stool or flatus.

Increasing continuous pain, marked local tenderness, erythematous or dusky skin, fever, persistent tachycardia, peritonism or systemic deterioration suggests progression to strangulation.

No single clinical or laboratory finding reliably excludes early bowel ischaemia.

An obvious incarcerated external hernia is primarily a clinical diagnosis.

CT abdomen and pelvis with IV contrast: useful when the anatomy is unclear, obstruction is present or strangulation is uncertain; assess the trapped bowel and its perfusion.

Imaging should not delay surgery when strangulation is strongly suspected.

Keep fasting, establish IV access and correct dehydration and electrolyte abnormalities when obstruction is present.

Nasogastric decompression is appropriate with persistent vomiting or substantial bowel obstruction.

A recently incarcerated hernia can undergo careful manual reduction, or taxis, only when there is no clinical evidence of strangulation.

Use adequate analgesia, position the patient comfortably and apply sustained gentle pressure rather than forceful manipulation.

Do not attempt taxis when there is:

• Peritonitis
• Marked local inflammatory change
• Strong suspicion of bowel ischaemia
• Haemodynamic instability
• Clinical deterioration

Failure of gentle reduction requires operative repair.

After successful reduction, persistent abdominal pain, vomiting or obstruction should raise concern for reduction en masse or already compromised bowel and warrants urgent reassessment.

Definitive hernia repair should be performed during the same admission or soon afterwards according to the presentation and patient factors.

For an emergency clean mesh repair, give surgical prophylaxis:

Cefazolin 2 g IV within 60 minutes before incision. Use 3 g IV when body weight is 120 kg or greater.

At surgery, assess the previously trapped bowel. Synthetic mesh is appropriate when bowel is viable and the field is clean. It may also be used in selected cases requiring bowel resection without gross enteric spillage.