Inguinal hernia

Inguinal hernias (herniae also used) is the type of groin herniation (part of the larger group of abdominal wall hernias) that occurs above the inguinal ligament and through the inguinal canal.

Epidemiology

They are the commonest type of abdominal wall herniation (up to 80% ³) and are most often acquired. There is a recognized male predilection with an M:F ratio of up to 7:1 ³.

Clinical presentation

Patients most commonly present with swelling and/or pain in the relevant groin, iliac fossa, loin. Men may also have testicular pain.

Pathology

Classification

It is broadly divided into two types:

• indirect inguinal hernia (more common)
  • herniates lateral to the inferior epigastric vessels ²
  • passes through the deep inguinal ring
  • anterior to the spermatic cord in males ⁸
  • follows the round ligament in females ⁸
• direct inguinal hernia (less common)
  • herniates medial to the inferior epigastric vessels ²
  • passes through a defect in the Hesselbach triangle
  • a weakness in the fascial floor of the inguinal canal ¹⁰

Etiology

All of the following confer an increased risk for indirect inguinal hernia:

• prematurity and low birth weight ⁹
• patent processus vaginalis
• urologic conditions (e.g. cryptorchidism, hypospadias or epispadias, bladder exstrophy, ambiguous genitalia)
• abdominal wall defects (omphalocele, gastroschisis, cloacal exstrophy, bladder exstrophy)
• family history

A direct inguinal hernia is a consequence of weakened abdominal musculature, often brought on by

• advanced age
• strain
• previous abdominal surgery

While inguinal hernias, in general, are much more common in males than in females, direct hernias, in particular, are rare in women since the broad ligament acts as an additional barrier.

Treatment and prognosis

Surgical treatment options include

• herniorrhaphy
• hernioplasty

Complications

Complications, as in any other abdominal wall herniation, include:

• incarceration
• strangulation
• bowel obstruction

Compared with other types of abdominal wall hernias, the incidence of complications is considered lower ³.

Differential diagnosis

Possible imaging differential considerations include

• femoral hernia: often remain lateral to the pubic tubercle and compress the femoral vein
• hydrocele (may coexist)
• varicocele