Classification

• When a hernia can no longer be reduced, it is irreducible or incarcerated.
• This can occur at any time, as can strangulation when visceral contents of hernia become twisted or entrapped by narrow opening. This compromises the blood supply causing swelling and eventually infarction.
• Strangulation leads to bowel obstruction.

Abdominal wall hernias are named according to the position of the fault in the abdominal wall. The common types include:

• Femoral hernias
• Inguinal hernias
• Incisional hernias
• Epigastric hernias
• Umbilical hernias

Femoral and inguinal hernias are covered in detail in separate records.

Epigastric hernias

Presentation

• The defect is seen approximately mid-line above the umbilicus in the linea alba.
• Occurs in 3-5% of the population - most commonly in men aged 20-30 years.
• In approximately 20% cases there are multiple hernias.
• They are usually asymptomatic, but can present with epigastric pain varying from mild, to severe and penetrating. It may be accompanied by bloating, nausea and vomiting, often after meals.
• Small hernias may be tender.
• The hernia can be made to bulge by asking the patient to strain.

Management

• Obese patients may need ultrasound or CT to confirm diagnosis.
• They need to be differentiated from a diastasis recti, which is a widening of the linea alba without a defect in the fascia.
• Surgical repair is essential as there is a high risk that they will incarcerate or strangulate.
• There is a 10-20% risk of recurrence after repair.

Incisional hernias

Presentation

• These occur following > 10% of abdominal operations.
• They are caused by failure of the wound to heal.
• Advances in technique and materials have not removed this problem.¹

Management

• They require urgent repair with reinforcing mesh used in large hernias. This is required particularly where the patient is obese.² Recurrence occurs in up to 50% of large hernias.

Umbilical hernias

Presentation

• Umbilical hernias comprise 10-30% of all hernias. It is a common defect, especially in premature babies.
• Caused by late opening of umbilical ring and more commonly seen in women associated with multiple pregnancies and difficult labour.
• In men and women they are also found in cases of abdominal swelling, e.g. ascites and obesity.
• Hernia gradually enlarges and may be multi-loculated.
• Sac normally contains omentum ± bowel.
• May present with pain on coughing or straining, or an ache or dragging sensation if large.

Management

• If < 1 cm diameter, nearly always closes without treatment by age 5 years.
• If > 1.5 cm or child aged > 4 years, usually requires repair.
• Hernia only rarely becomes incarcerated.³
• Hernia is repaired surgically with preservation of umbilicus, after removing causative factors such as ascites.

Rare hernias in adults

• Spigelian: hernia through the linea semilunaris muscle. Initially causes localised pain exacerbated by straining and coughing, but pain may become less localised and more an ache with time. Bulge can often be seen in lower abdomen with patient erect and straining. This can be reduced by pressure with a 'gurgling' noise and then hernia orifice can often be felt. However, defect may not be palpable or bulge found distant from site. Needs prompt repair.
• Littre's: hernia sac contains a Meckel's diverticulum. Half are inguinal, 20% femoral, 20% umbilical.
• Lumbar or dorsal: nearly always occurs in the superior and inferior lumbar triangles. Presents with a lump in the side with a heavy, pulling sensation.
• Obturator canal: occurs mainly in elderly women and carries a mortality of up to 40%. Presents with symptoms of small bowel obstruction. Usually only palpable on pelvic or rectal examination.
• Perineal: usually occurs after perineal surgery and presents with asymptomatic swelling.
• Sciatic: very rare, with herniation through greater sciatic foramen with incarceration or strangulation of the bowel.
• Sportsman's: a debilitating condition which presents as chronic groin pain. A tear occurs at the external oblique which may result in an occult hernia.⁴
• Traumatic: follows blunt trauma and presents with pain, bruising and bulge.