What is the difference between an incarcerated hernia and a strangulated hernia, and how are they managed?

Incarcerated vs Strangulated Hernia: Differences and Management

Incarcerated hernias are trapped hernias that cannot be reduced, while strangulated hernias have compromised blood supply to the trapped tissue and require immediate surgical intervention.

Definitions and Differences

Incarcerated Hernia

• Definition: A hernia that cannot be reduced or pushed back into the abdominal cavity
• Characteristics:
  • Contents are trapped but blood supply is intact
  • May cause pain and discomfort
  • Can progress to strangulation if left untreated

Strangulated Hernia

• Definition: An incarcerated hernia with compromised blood supply to the trapped tissue
• Characteristics:
  • Severe, constant pain
  • Erythema or skin changes over the hernia
  • Systemic signs: fever, tachycardia, peritoneal signs
  • Laboratory markers: elevated lactate, CPK, and D-dimer levels 1
  • Medical emergency requiring immediate surgical intervention

Clinical Assessment

Signs of Strangulation

• Severe and constant pain (not intermittent)
• Redness or skin changes over the hernia
• Nausea and vomiting
• Inability to pass gas or stool
• Fever or general malaise 1
• Tachycardia and peritoneal signs
• Systemic inflammatory response syndrome (SIRS) 1

Management Approach

Incarcerated Hernia

1. Reduction attempt:

   • Taxis (manual reduction) can be attempted in selected cases 2
   • Ultrasound-guided nerve blocks (e.g., rectus sheath block) may aid in reduction 3
   • Success rates of approximately 60% have been reported with taxis 2

2. If reduction is successful:

   • Observe for 24 hours to monitor for complications 2
   • Plan for elective repair after resolution of local inflammation

3. If reduction fails:

   • Surgical intervention is required, but it's not as urgent as for strangulation
   • Both open and laparoscopic approaches are viable options 4

Strangulated Hernia

1. Immediate surgical intervention is mandatory 5, 1

   • Preoperative preparation includes:
     • Fluid resuscitation
     • Broad-spectrum antibiotics
     • NPO status 1

2. Surgical approach:

   • Early intervention (<6 hours from symptom onset) is associated with lower incidence of bowel resection 6
   • Open approach is preferred for hemodynamically unstable patients or when bowel resection is anticipated 1
   • Laparoscopic approach may be considered in stable patients:
     • Associated with decreased recurrence rates
     • Shorter hospital length of stay 6
     • Average operating time of approximately 61 minutes 4

3. Mesh considerations:

   • Mesh repair is recommended even in emergency settings for clean surgical fields (CDC wound class I)
   • Primary repair is recommended for small defects (<3 cm) in contaminated fields 1
   • Mesh repair is associated with decreased incidence of recurrence 6

Postoperative Care

• Inpatient monitoring for at least 24 hours
• Focus on hemodynamic stability and surgical site
• Pain management with acetaminophen as first-line agent
• Avoid NSAIDs due to increased risk of bleeding 1
• Monitor for complications:
  • Wound infection (4-12% incidence)
  • Recurrence (10.6-12.3% with mesh repair vs 17.1% without mesh) 1

Important Considerations

• Femoral and direct inguinal hernias have higher rates of strangulation 7
• Always exclude strangulated hernia in patients with intestinal obstruction 7
• Bowel resection may be required in approximately 13.7% of complicated hernia cases 1
• Special populations (pregnant women, patients with high bleeding risk, cirrhotic patients) require specialized management approaches 1

Common Pitfalls to Avoid

1. Delaying surgical intervention for suspected strangulation
2. Failing to recognize signs of strangulation in a previously diagnosed incarcerated hernia
3. Not providing adequate preoperative resuscitation
4. Using NSAIDs for pain management in these patients
5. Missing deeply located hernias (especially femoral) in patients with intestinal obstruction