What is the management of an incarcerated hernia?

Management of Incarcerated Hernia

Immediate surgical intervention is mandatory when intestinal strangulation is suspected, and should be performed within 6 hours of symptom onset to minimize bowel resection and mortality. 1, 2

Initial Assessment and Risk Stratification

Signs Requiring Immediate Surgery

• Systemic inflammatory response syndrome (SIRS) - fever, tachycardia, and leukocytosis indicate likely strangulation 1
• Continuous abdominal pain with abdominal wall rigidity or obvious peritonitis mandates emergency operation 1
• Elevated laboratory markers - lactate ≥2.0 mmol/L, elevated CPK, D-dimer, and fibrinogen levels predict bowel strangulation 3, 1
• Contrast-enhanced CT findings suggesting bowel wall ischemia or reduced wall enhancement 3, 1

High-Risk Features for Bowel Resection

• Symptom duration >8 hours significantly increases morbidity 1
• Femoral hernia (OR = 8.31 for bowel resection) 1
• Obvious peritonitis (OR = 11.52 for bowel resection) 1
• Delayed treatment >24 hours dramatically increases mortality (2.4% increase per hour of delay) 1

Manual Reduction (Taxis)

Manual reduction may be attempted ONLY when all of the following criteria are met: 1, 4

• Symptoms present for <24 hours 1
• No signs of strangulation (no SIRS, continuous pain, or peritonitis) 1
• Patient is hemodynamically stable 1

Technique

• Perform under intravenous sedation and analgesia (morphine + short-acting benzodiazepine) 4
• Place patient in Trendelenburg position 1
• If successful, patient requires same-admission surgery - not delayed repair 5

Critical Pitfall

Spontaneous reduction does NOT exclude bowel ischemia - the bowel may have been compromised during incarceration and reduced back while still ischemic. If a chronic reducible hernia suddenly becomes painful and then "disappears" with new abdominal tenderness, this suggests auto-reduction of potentially ischemic bowel requiring urgent diagnostic laparoscopy. 5

Surgical Approach Selection

Laparoscopic Approach (Preferred When Appropriate)

Laparoscopic repair is recommended for incarcerated hernias WITHOUT signs of strangulation or anticipated bowel resection. 3, 2, 6

Benefits include: 3, 7, 6

• Significantly lower wound infection rates (P<0.018) 3
• No increase in recurrence rates (P<0.815) 3
• Shorter hospital stay (mean difference -3.00 days) 2
• Ability to identify occult contralateral hernias (present in 11.2-50% of cases) 7

Contraindications to laparoscopic approach: 7

• Suspected or confirmed bowel strangulation requiring resection 3, 7
• Obvious peritonitis 1
• Inability to tolerate general anesthesia 7

Open Preperitoneal Approach

Open approach is mandatory when: 1, 7

• Bowel resection is anticipated 3, 7
• Strangulation is confirmed 1
• Laparoscopic expertise unavailable 7

Advantage: Can be performed under local anesthesia in incarcerated inguinal hernias without bowel gangrene 3, 7

Hernioscopy (Diagnostic Laparoscopy)

Hernioscopy through the hernia sac is specifically recommended to assess bowel viability after spontaneous reduction of strangulated groin hernias. 3, 5

• Prevents unnecessary laparotomy 3
• Decreases hospital stay (median 28h vs 34h) 3
• Reduces major complications and mortality in high-risk patients 3

Mesh Selection Based on Surgical Field

Clean Field (CDC Class I) - No Strangulation, No Bowel Resection

Prosthetic repair with synthetic mesh is strongly recommended (Grade 1A). 3, 1, 7

• Significantly lower recurrence rate (0% vs 19% with tissue repair, P<0.05) 3, 2
• No increase in wound infection rate 3

Clean-Contaminated Field (CDC Class II) - Strangulation WITH Bowel Resection, No Gross Spillage

Emergent prosthetic repair with synthetic mesh is still recommended. 3, 1, 7

• Significantly lower recurrence risk regardless of defect size 7
• No increased infection risk compared to tissue repair 3

Contaminated/Dirty Field (CDC Class III-IV) - Bowel Necrosis with Spillage or Peritonitis

For small defects (<3 cm): Primary tissue repair is recommended. 7, 5

For larger defects when direct suture not feasible: 7

• Biological mesh may be used 7
• If biological mesh unavailable: polyglactin mesh or open wound management with delayed repair 7

Anesthesia Selection

• General anesthesia is required when bowel gangrene is suspected or intestinal resection needed 1, 7
• Local anesthesia is appropriate for incarcerated inguinal hernias without bowel gangrene via open approach 3, 7

Antimicrobial Prophylaxis

• Short-term prophylaxis for intestinal incarceration without ischemia 1
• 48-hour antimicrobial prophylaxis for intestinal strangulation and/or concurrent bowel resection (CDC classes II-III) 1, 7
• Full antimicrobial therapy for patients with peritonitis (CDC class IV) 7

Critical Timing Considerations

Elapsed time from symptom onset to surgery is the single most important prognostic factor (P<0.005). 1

• Early intervention (<6 hours) associated with lower incidence of bowel resection (OR 0.1, P<0.0001) 2
• Delay >24 hours results in dramatically higher mortality rates 1
• Each hour of delay increases mortality by 2.4% 1

Common Pitfalls

• Early strangulation is difficult to detect by clinical or laboratory means alone - maintain high index of suspicion 1
• Classic signs of strangulation may be absent - do not wait for obvious peritonitis before operating 1
• Women, patients >65 years, and femoral hernias warrant lower threshold for immediate surgery rather than reduction attempts 1
• Imaging should not delay surgical exploration when clinical suspicion of strangulation exists 5