33. Hernias: definition, types, diagnosis, complications and treatment

Hernias: definition, types, diagnosis, complications and treatment

DEFINITION & ANATOMY

• A hernia is protrusion of a viscus or tissue through a weakness or defect in the wall that normally contains it. Most abdominal hernias involve peritoneum and may contain bowel, omentum or other structures.
• Components include the hernial orifice/defect, sac (when present), contents and coverings. Predisposing factors include connective-tissue weakness, age, obesity, smoking, pregnancy, chronic cough, constipation, ascites and previous surgery.
• Classify as external or internal; congenital or acquired; reducible, incarcerated (irreducible) or strangulated; primary or incisional; and by anatomical site.

COMMON TYPES

• Groin hernias include inguinal (direct or indirect) and femoral hernias. Other abdominal wall hernias include umbilical, paraumbilical, epigastric, Spigelian, lumbar and incisional hernias.
• Internal hernias occur through intra-abdominal or mesenteric defects and may cause bowel obstruction without an external lump.
• Richter hernia involves only part of the bowel circumference and may strangulate without complete obstruction. Littre hernia contains a Meckel diverticulum. Maydl hernia has two bowel loops in the sac with an intra-abdominal loop at risk.

CLINICAL FEATURES & DIAGNOSIS

• Typical presentation is a lump that appears or enlarges on standing, coughing or straining and may reduce when supine. Symptoms include dragging discomfort or pain.
• Examine standing and supine, inspect both groins and abdominal wall, palpate the defect and assess cough impulse and reducibility. Document size, tenderness, skin change and contents where possible.
• Diagnosis is usually clinical. Ultrasound is useful for occult groin or equivocal hernias; CT is useful for complex, incisional, internal or obstructed hernias and operative planning.
• Differentiate from lymphadenopathy, hydrocele, varicocele, lipoma, femoral artery aneurysm, undescended testis and soft-tissue tumour.

COMPLICATIONS

• Incarceration means the hernia cannot be reduced. Obstruction causes colicky pain, vomiting, distension and inability to pass stool/flatus.
• Strangulation compromises blood supply, causing constant severe pain, tenderness, systemic toxicity, fever, tachycardia, skin erythema and eventually peritonitis or shock.
• Strangulation is a surgical emergency. Do not attempt forceful reduction when strangulation is suspected.

TREATMENT

• Management depends on type, symptoms, operative risk and patient preference. Watchful waiting may be appropriate for selected minimally symptomatic men with uncomplicated inguinal hernia, but not for femoral hernia because of higher strangulation risk.
• Elective repair may be open or laparoscopic, with mesh commonly used for adult groin and many ventral hernias. Tissue repair is selected in specific circumstances, including contamination or when mesh is unsuitable.