Abdominal Wall Hernias

A hernia is a protrusion of abdominal contents through the fascia of the abdominal wall. Hernias always contain a portion of peritoneal sac and may contain viscera, usually small bowel and omentum.
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.

The defect is seen approximately mid-line above the umbilicus in the linea alba. Occurs in 3-5% population most commonly in men aged 20-30 years. In approx. 20% cases there are multiple hernias.

Presentation

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 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.

Here the protrusion is through the abdominal wall via the femoral canal. They are rarer than inguinal hernias, especially in men, but also in women.

Presentation

Often symptoms only occur with incarceration or strangulation. At this time there may be colicky pain and signs of obstruction, rather than local symptoms.

Management

They should all be operated on immediately, as they have a high potential for strangulation. It is not advisable to use a truss. During repair contents are removed from the hernial sac and excised. Then the femoral canal is sutured closed.

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.

Virtually all are indirect. Inguinal hernias comprise 75% of all hernias. They are 25 times more common in men. Inguinal hernia repair is one of the most common operations in general surgery with a rate of repair of 10 per 10,000 population in the United Kingdom.³

• Indirect: A protrusion through the internal inguinal ring passes along the inguinal canal through the abdominal wall. May protrude into scrotum.
• Direct: Hernia protrudes directly through the abdominal wall into inguinal canal. It is more common in the elderly and rare in children. Rarely protrudes into scrotum.

Presentation

Presents with bulge in groin. In children it is best seen with baby crying or straining. Need to exclude undescended testis and communicating hydrocele. The hernia incarcerates in approx.10% cases and then strangulates in approx. 33% cases.

Management

May also cause infarction of the testis by compression of the spermatic cord. Therefore, surgical repair should not be greatly delayed. Laparoscopic techniques reduce post-operative pain and recovery time, but are associated with greater operating time and potentially serious complications e.g. vascular/visceral injury (rarely).^5,6 It is particularly advocated in children.

Umbilical hernias comprise 10-30% of all hernias. 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.

Presentation

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 <1cm diameter, nearly always closes without treatment by age 5 years. If >1.5cm or child aged >4 years, usually requires repair. Hernia only rarely becomes incarcerated.⁷ Hernia is repaired surgically with preservation of umbilicus, after removing causative factors such as ascites.

• Spigelian; hernia through the linea semilunaris muscle. Initially cause 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 be often 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.
• Obdurator 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.⁸
• Traumatic; follows blunt trauma and presents with pain, bruising and bulge.