In an otherwise healthy adult, what are the common external abdominal wall hernias and what is the recommended management for each, including urgency of repair and preferred mesh techniques?

Common External Abdominal Wall Hernias and Management

Most Common Hernia Types (in Order of Frequency)

The current epidemiological data shows inguinal hernias remain most common, followed by umbilical, epigastric, incisional, para-umbilical, and femoral hernias—a significant shift from historical teaching where femoral hernias were second most common. 1

• Inguinal hernias are universally the most common type requiring repair 1
• Umbilical hernias have become the second most common, replacing femoral hernias which have dropped to fifth place 1
• Epigastric hernias rank third in frequency 1
• Incisional hernias occur at previous surgical sites and rank fourth 1
• Femoral hernias have decreased significantly in relative frequency over the past 30 years 1

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General Principles for Elective Repair

Timing of Repair

All symptomatic umbilical and epigastric hernias should be repaired electively to prevent emergency presentations, as conservative management is inappropriate and leads to significantly higher morbidity. 2

• Defects of 3-4 cm width carry the highest risk of incarceration (OR 2.85 for primary hernias, OR 2.14 for incisional hernias) and should be prioritized for repair 3
• Peri-umbilical and infra-umbilical defects have nearly double the odds of incarceration compared to supra-umbilical defects (OR 1.98) 3
• Emergency repair results in 46.2% complication rate versus significantly lower rates with elective repair 2
• Emergency presentations require bowel resection in approximately 15% of cases 2

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Mesh Technique Recommendations by Hernia Type

Umbilical and Epigastric Hernias

The European Hernia Society and Americas Hernia Society recommend mesh repair for all umbilical and epigastric hernias using an open preperitoneal flat mesh approach as the primary technique. 4

Surgical Approach Selection:

• Open preperitoneal mesh is recommended for most umbilical and epigastric hernias as the standard approach 4
• Laparoscopic approach (TAPP or TEP) should be considered for large defects or patients at increased risk of wound morbidity 4, 5
• Mesh should extend at least 3 cm beyond the defect boundaries in all directions 5

Mesh Type by Surgical Field Classification:

Clean Fields (CDC Class I):

• Synthetic mesh is the standard for all uncomplicated hernias without contamination 5, 6
• Mesh significantly reduces recurrence rates (0-4.3%) compared to tissue repair (19%) without increasing infection risk 5

Clean-Contaminated Fields (CDC Class II):

• Synthetic mesh can be safely used even with intestinal strangulation and/or bowel resection without gross enteric spillage 5, 6
• No significant increase in 30-day wound-related morbidity compared to clean fields 5

Contaminated/Dirty Fields (CDC Class III-IV):

• Primary repair without mesh is recommended for small defects (<3 cm) with bowel necrosis or gross spillage 5, 7, 6
• Biological mesh should be used when direct suture is not feasible for larger defects 5, 7, 6
• Cross-linked biological mesh provides better mechanical resistance for larger defects 5, 7
• Polyglactin mesh is an alternative when biological mesh is unavailable 5

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Incarcerated Hernia Management

Assessment and Decision Algorithm

For incarcerated hernias without strangulation, laparoscopic repair may be performed, but open preperitoneal approach is preferable if bowel resection is anticipated. 8

Manual Reduction Criteria:

• Consider only if onset <24 hours, no signs of strangulation, and minimal pain 5
• Normal vital signs must be present 5
• Patient must be educated on red flag symptoms requiring immediate return 5

Red Flags Requiring Emergency Surgery:

• Tachycardia ≥110 bpm is the earliest warning sign and should never be dismissed 5
• Fever ≥38°C combined with tachycardia and abdominal pain 5
• Persistent vomiting indicating possible bowel obstruction 5
• Signs of sepsis (hypotension, altered mental status, decreased urine output) 5
• Skin changes over hernia (redness, discoloration, necrosis) 5
• Symptoms persisting >8 hours (associated with significantly higher morbidity) 5

Surgical Approach for Incarcerated Hernias

Diagnostic laparoscopy is useful for assessing bowel viability after spontaneous reduction of strangulated groin hernias. 8

• Laparoscopic repair shows significantly lower wound infection rates (P<0.018) without higher recurrence rates in strangulated groin hernias 8
• Hernioscopy (mixed laparoscopic-open technique) effectively evaluates viability of herniated loops and avoids unnecessary laparotomy 8
• Open preperitoneal approach is preferable when bowel resection is suspected 8

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Special Population: Cirrhotic Patients with Ascites

Risk Assessment

Emergency surgery in cirrhotic patients carries dramatically increased mortality (OR=10.32) compared to elective repair, making preoperative optimization critical. 5

• Umbilical hernias occur in up to 24% of cirrhotic patients with ascites 5
• Child-Pugh-Turcotte class C increases mortality risk (OR=5.52) 5
• MELD score ≥20 increases mortality risk (OR=2.15) 5

Preoperative Optimization Protocol:

Aggressive medical ascites control through sodium restriction to 2000 mg/day and diuretic therapy (spironolactone up to 400 mg/day plus furosemide up to 160 mg/day in 100:40 ratio) is mandatory before elective repair. 5

• Large volume paracentesis with albumin infusion (8 g/L if >5L removed) for symptomatic relief 5
• TIPSS should be considered to facilitate better ascites control 5
• Avoid large volume paracentesis immediately before or after surgery as rapid ascites removal can paradoxically cause incarceration 5

Emergency Indications in Cirrhotic Patients:

Emergency surgery is mandatory for strangulated, incarcerated non-reducible, or ruptured hernias despite refractory ascites. 5

• Hepatology consultation is mandatory for postoperative ascites management 5
• Surgery should be performed by a surgeon experienced with cirrhotic patients 5
• TIPS placement should be considered postoperatively if ascites cannot be controlled medically 5

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Antimicrobial Prophylaxis

Antimicrobial prophylaxis duration should be tailored to CDC wound classification. 5

• CDC Class I (clean): Short-term prophylaxis only 5, 6
• CDC Class II-III (clean-contaminated/contaminated): 48-hour prophylaxis 5, 6
• CDC Class IV (dirty/peritonitis): Full antimicrobial therapy 5, 6

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Critical Pitfalls to Avoid

• Never avoid mesh in clean or clean-contaminated fields due to unfounded fear of infection—evidence shows it's safe and dramatically reduces recurrence 5, 6
• Never use synthetic mesh in grossly contaminated fields (CDC Class III/IV) as infection rates can reach 21%, often requiring complete mesh explantation 5, 7
• Never dismiss tachycardia as insignificant—it may be the only early sign of serious complications 5
• Never perform tissue repair for umbilical/epigastric hernias when mesh is feasible, as recurrence rates are unacceptably high (19% vs 0-4.3%) 5
• Never rapidly remove ascites perioperatively in cirrhotic patients as this paradoxically increases incarceration risk 5
• Elapsed time from symptom onset to surgery is the most important prognostic factor (P<0.005) for emergency presentations 5