Special types of hernia

Richter’s hernia

A portion of the circumference of the small intestine is trapped, which may become ischaemic but without the development of intestinal obstruction (Fig. 15.1).

Figure 15.1 Richter’s hernia. Part of the bowel wall has strangulated in the hernia but the lumen of the bowel is not obstructed. This is most commonly seen in strangulated femoral hernias.

Symptoms

Signs

The patient should be examined in the supine and erect positions. The area of the swelling is palpated to determine its reducibility and whether an expansile cough impulse is present. A hernia is more likely to be reducible with the patient supine. Control of the hernia by direct pressure over the point at which reduction occurs locates the neck of the sac. Other hernial sites should be examined (bilateral groin hernias are common).

A strangulated hernia is painful, tender and irreducible. The surrounding tissues may be inflamed. Signs of small bowel obstruction may be present.

A general physical examination must be carried out to search for predisposing causes, e.g. benign prostatic hyperplasia or chronic cough.

Surgical techniques

Herniotomy, the removal of the sac and closure of its neck, is all that is required for infant inguinal hernia and is the first step in nearly all hernia repairs.

Herniorrhaphy involves restoration of normal anatomy, increasing the strength of the abdominal wall and constructing a barrier to recurrence. The most commonly used procedure is the insertion of a prosthetic mesh. Patients with obstruction and strangulation need general preoperative resuscitation prior to surgical exploration. Non-operative treatment may be considered in infants.

Outcome

For elective repair, the overall mortality is less than 0.5%. For emergency operations it is 5%. Mortality is dependent on the age of the patient and whether or not the contents of the sac are gangrenous.

Postoperative morbidity

Particular, persistent wound pain occurs in up to 11% of patients. Cutaneous anaesthesia is also common following hernia repair. Recurrent hernia with the use of a mesh is now less than 1%.

Inguinal hernia

Inguinal hernias account for 80% of all abdominal hernias. They are most common in infants and the elderly. Inguinal hernias are twenty times more common in men than women and occur more frequently on the right side.

An indirect inguinal hernia passes through the internal ring, lateral to the inferior epigastric artery, along the canal to emerge at the external ring above the pubic crest and tubercle. Its coverings are attenuated layers of the cord. An indirect hernia may extend into the scrotum.

A direct inguinal hernia bulges through the posterior wall of the canal, medial to the inferior epigastric artery and is therefore not covered by layers of the cord. Direct hernias cannot extend into the scrotum.

A pantaloon hernia is a combination of the two.

Indirect hernias are usually derived from a remnant of the processus vaginalis which does not close. It is therefore more common in infancy. Sixty per cent occur on the right side and they are twenty times more common in men than women. Direct hernias are acquired lesions and usually a condition of later life. The differences between an indirect and direct inguinal hernia are shown in Table 15.1.

Table 15.1 Differences between indirect and direct inguinal hernia

A key feature in distinguishing between an inguinal and a femoral hernia is the pubic tubercle, which may be found by feeling laterally along the pubic crest on the upper border of the symphysis pubis or by following the adductor longus tendon from the medial side of the thigh to its origin from the body of the pubis. The tubercle is directly above this. A reducible indirect inguinal hernia can be completely controlled with a fingertip firmly placed over the internal ring at the midpoint of the inguinal ligament. Differential diagnosis includes a femoral hernia, hydrocele, hydrocele of the cord or canal of Nuck, undescended testis, lipoma of the cord or epididymal cyst.

General principles of hernia repair have been given above. Postoerative complications include urinary retention in the male, scrotal haematoma or damage to the ilioinguinal nerve, causing an area of anaesthesia, or continued postoperative groin pain. Recurrent inguinal hernias should be repaired to avoid the same complications that occur with primary hernias. Note the possibility of orchidectomy or testicular damage, which may occur with open repair due to damage of the testicular artery. Damage to the vas deferens is also possible.

Femoral hernia

The differential diagnosis of a femoral hernia is shown in Table 15.2. Femoral hernias account for 7% of all hernias and are four times more common in women than men (although inguinal hernias are still more common in women than femoral). They are most common in late middle age and are rare in children. Bilateral hernias occur in 20%. The femoral canal is bounded by the inguinal ligament (anteriorly), the lacunar part of the inguinal ligament (medially) and the pectineal part of the inguinal ligament (posteriorly). This narrow femoral ring produces considerable risk of incarceration of any hernia. The narrow canal makes femoral hernia the one most likely to result in a Richter’s hernia.

Table 15.2 Inguinal swellings which may resemble a femoral hernia

Clinical features

The patient is typically a middle-aged or elderly woman, complaining of a low lump in the groin; 20% present with strangulation. Cough impulses are difficult to detect. The femoral hernia is always below and lateral to the pubic tubercle, distinguishing it from an inguinal hernia. Small bowel obstruction may classically present in a strangulated femoral hernia and the hernia may easily be missed on clinical examination if the diagnosis is not thought about.

All femoral hernias should be repaired by direct incision over the hernia and closure of the femoral canal or occasionally from above in patients with obstruction or strangulation.

Management

In true umbilical hernias, an underlying cause should be sought and dealt with. Para-umbilical hernias, if symptomatic, require treatment (Figs 15.2 and 15.3). A strangulated umbilical hernia needs urgent exploration.

Figure 15.2 (a) Umbilical and (b) para-umbilical hernia.

Figure 15.3 Repair of a para-umbilical hernia.

Aetiology

Incisional hernias may be caused by preoperative, operative or postoperative factors.

Preoperative factors

Operative factors

Postoperative factors

Pathological features

Most incisional hernias occur within a year of operation and, once formed, inexorably enlarge. They may be wide or narrow-necked. Incarceration and strangulation may occur. The overlying skin may become thin and atrophic and the patient may complain of local discomfort. Small symptomatic hernias should be repaired, along with asymptomatic hernias, to prevent the risk of intestinal obstruction or skin ulceration. The outcomes of surgery are variable. Larger defects require mesh repair. Many cases are now repaired laparoscopically.