Abdominal hernias

Abdominal hernias always contain a portion of peritoneal sac and may contain viscera, usually small bowel and omentum.

A large number of abdominal hernias require emergency surgery. However, these procedures may be associated with poor prognosis and a significant rate of postoperative complications. Wound infection is the most common complication encountered and represents an immense burden especially in the presence of a mesh.¹

Classification of abdominal hernias¹

• 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 the narrow opening. This compromises the blood supply, causing swelling and eventually infarction.

• Strangulation leads to bowel obstruction.

Abdominal hernias may be classified as groin hernias (femoral or inguinal) and ventral hernias (umbilical, epigastric, Spigelian, lumbar, and incisional).

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

Epigastric hernias²

Symptoms and presentation

• The defect is seen approximately midline above the umbilicus in the linea alba.

• Prevalence is estimated at 0.5-10%, accounting for between 1.6-3.6% of all abdominal hernias.

• Most common in men between the ages of 20 and 50 years.

• Multiple abdominal hernias may be present.

• 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.

Treatment and management

• Obese patients may need ultrasound or CT scanning 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 traditional repair by primary suture; however, this is reduced if polypropylene mesh is used.^{3 4}

Incisional hernias

Symptoms and presentation

• Incisional hernia is a risk of any abdominal surgery and is estimated to occur in 12.8% of abdominal operations.⁵

• They more commonly occur following open surgery but do also happen following laparoscopic surgery.⁶

• They are caused essentially by failure of the wound to heal but are probably the result of multiple patient and technical factors.

• Attention to closure technique and suture material can reduce incidence. For example, monofilament sutures may reduce the risk of incisional hernia. However, a Cochrane review of wound closure methods found that further studies were required.⁷

Treatment and management

• They require urgent repair with reinforcing mesh used in large abdominal hernias. This is required particularly where the patient is obese.⁸

• There is good evidence that open mesh repair is superior to suture repair in terms of recurrences, but inferior when considering wound infection.

• Recurrence occurs in up to 50% of large hernias and is more common in patients who are very overweight.

Umbilical hernias³

Symptoms and presentation

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

• They can be broadly categorised into the following groups:
  

  • Congenital hernia (also called omphalocele) - can be further subdivided into fetal (occurring after eight weeks in utero) and embryonic (occurring before eight weeks in utero and may be associated with herniation of other abdominal cavity organs).

  • Infantile hernia - associated with prematurity; it usually spontaneously resolves.

  • Adult umbilical hernia - 90% of these are acquired - eg, in women they are associated with multiple pregnancies and difficult labour; however, they are also found in cases of abdominal swelling - eg, ascites and obesity. They result in both high levels of mortality and morbidity.

• 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 a dragging sensation if large.

Treatment and management

• If <1 cm diameter, nearly always closes without treatment by age 5 years.

• If >1.5 cm or in a child aged >4 years, usually requires repair.

• Hernia is repaired surgically with preservation of the umbilicus, after removing causative factors such as ascites.

Rare hernias in adults

• Spigelian: this is a hernia through the linea semilunaris muscle. Initially this causes localised pain exacerbated by straining and coughing, but the pain may become less localised and more an ache with time. Bulge can often be seen in the lower abdomen with the patient erect and straining. This can be reduced by pressure with a 'gurgling' noise and then the hernia orifice can often be felt. However, the defect may not be palpable or a bulge may be found distant from the site. This needs prompt repair.⁹

• Littre's: the hernia sac contains a Meckel's diverticulum. 50% are inguinal, 20% femoral, and 20% umbilical. The remaining 10% are in miscellaneous locations - eg, ventral incisional hernia.¹⁰

• Lumbar or dorsal: these nearly always occur in the superior and inferior lumbar triangles. They present with a lump in the side with a heavy, pulling sensation.

• Obturator canal: these occur mainly in elderly women and carry a mortality of up to 40%. They present with symptoms of small bowel obstruction. Usually they are only palpable on pelvic or rectal examination.

• Perineal: these usually occur after perineal surgery and present with asymptomatic swelling.

• Sciatic: these are very rare, with herniation through the 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.¹¹

• Traumatic: these follow blunt trauma and present with pain, bruising and bulge.