Hernias

A pantaloon hernia is a type of direct inguinal hernia where the hernia sac straddles the inferior epigastric vessels. Normally, a direct inguinal hernia passes medial to the inferior epigastric vessels, whereas an indirect hernia lies lateral to these.

A hernia is the abnormal protrusion of the whole, or part, of a viscus through its containing walls. A femoral hernia is the protrusion of contents, i.e. extraperitoneal fat, omentum or bowel, into the potential space of the femoral canal. Femoral hernias are three times more common in women than men and more commonly occur on the right side. They are differentiated from inguinal hernias in that they lie below and lateral to the pubic tubercle.

Inguinal hernias are caused by weakness in the abdominal wall at the entrance to the inguinal canal. They may be indirect (75%), passing through the internal inguinal ring and down the inguinal canal, or direct, passing through the posterior wall of the canal but not down the canal. Inguinal hernias are found above and medial to the pubic tubercle. The contents of a hernia may be returned to the abdominal cavity either spontaneously or with direct pressure, and this is described as a reducible hernia. There will be a cough impulse on examination. Hernias which cannot be returned to the abdominal cavity are described as irreducible or incarcerated. There will be no cough impulse on examination. Both reducible and incarcerated hernias are typically painless.

A strangulated hernia is one in which the blood supply to the contents is cut off; in other words where an irreducible hernia develops oedema and venous congestion, causing pressure on the arterial supply. The area subsequently becomes ischaemic and then gangrenous. Strangulation is common in femoral hernias due to the narrow neck of the femoral canal. Obstruction of bowel within the hernia sac presents with the typical features of vomiting, colicky abdominal pain, distension and absolute constipation, and may be associated with strangulation of bowel. If untreated, perforation and peritonitis occur. Strangulated and obstructed hernias are surgical emergencies.

Hernia, from Greek hernias = to sprout forth.

This man has a direct inguinal hernia that shows features of a Richter hernia. A Richter hernia describes strangulation of one sidewall of the bowel within a hernia sac. (By comparison, a strangulated hernia describes strangulation of the entire lumen of the bowel.) Richter hernias result in the features of strangulation (a painful, erythematous lump) but without the characteristics of obstruction.

A hernia is incarcerated when adhesions develop between the hernia sac and its contents, resulting in a painless irreducible lump which has no cough impulse. Incarcerated hernias predispose to strangulation. Strangulation occurs when a hernia twists upon itself and interferes with its blood supply, with ischaemia and necrosis developing within 6 hours. This can eventually result in perforation, which presents with a painful, rigid abdomen with pyrexia, tachycardia and vomiting.

August Richter, German surgeon (1742–1812).

In order of increasing priority, the options for managing hernias are observation, elective repair, prompt repair, urgent repair and emergency repair. Elective repairs are done at a mutually convenient time and prompt surgery is done within specific time limits. Urgent operations are done as soon as possible within 24 hours following adequate resuscitation. Emergency procedures are performed immediately for life-saving procedures where resuscitation is carried out at the same time as surgery.

This woman presents with a femoral hernia with features of obstruction. This requires emergency repair. Femoral hernias without features of strangulation or obstruction should still be repaired urgently, as there is a 50% risk of strangulation within a month.

This patient has presented with an incisional hernia. Incisional hernias are caused by a weakness in the abdominal wall at sites of previous abdominal incisions. They are a late complication in 10% of patients following abdominal surgery. Factors predisposing to an incisional hernia include poor surgical technique (too tight a closure), type of incision (vertical scars heal less well), post-operative wound infection, increasing age, obesity, chronic debilitating conditions such as diabetes, and steroid use. Incisional hernias are generally asymptomatic but may develop the same complications as other types of hernia, i.e. strangulation and obstruction. This patient is asymptomatic and therefore emergency surgery is not indicated. In view of her obesity and COPD, which would predispose to hernia recurrence, it would be safer to manage her conservatively unless circumstances change.