Description

Inguinal hernia is a protrusion of abdominal contents (intestine, omentum) into, and often through, the inguinal canal.

Epidemiology

• Inguinal hernia is the most frequent problem requiring elective surgical intervention in children.
• Significantly more common in boys (90% of cases)
• Has a familial tendency
• Laterality
  • Because of later descent of right testis and subsequently delayed obliteration of right processus vaginalis, inguinal hernia presents more frequently on the right side.
  • Clinical presentation is on the right side in 60% of cases, on the left side in 30%, and bilateral in 10%.
• Frequency varies with age and ranges from 3–5% in full-term babies to 10–30% in preterm infants.

Risk Factors

• Prematurity
• Urologic conditions:
  • Cryptorchidism
  • Hypospadias
  • Epispadias
  • Bladder exstrophy
• Abdominal wall defects:
  • Gastroschisis
  • Omphalocele
  • Eagle-Barrett syndrome
• Conditions that increase intra-abdominal pressure (e.g., ascites, peritoneal dialysis, ventriculoperitoneal shunt)
• Cystic fibrosis
• Connective tissue disease:
  • Marfan syndrome
  • Ehlers-Danlos syndrome
• Mucopolysaccharidoses
• Family history

Pathophysiology

• Indirect inguinal hernia
  • During the 7th month of male gestation, the testes begin their descent from the peritoneal cavity through the inguinal canal into the scrotum.
  • Between the 7th and 9th months of gestation, after the testes reach the scrotum, the path of peritoneum through which the testicle passed (processus vaginalis) begins to obliterate spontaneously, leaving only a small potential space adjacent to the testes (tunica vaginalis).
  • In girls, although the ovaries do not leave the abdomen, the round ligament (part of the gubernaculum) travels through the inguinal ring into labium majus. When the processus vaginalis remains open, it is identified as the canal of Nuck.
  • Incomplete obliteration of the processus vaginalis leaves a sac of peritoneum extending all the way from the internal inguinal ring to the scrotum or labium majus, through which an inguinal hernia may develop.
• Direct inguinal hernia
  • Uncommon in children
  • Results from either a congenital or acquired/traumatic weakness or tear in abdominal wall fascia
• Other types of inguinal hernias
  • Sliding hernia occurs when one wall of the hernia is composed of abdominal viscera (bladder, colon, adnexa).
  • Richter hernia results from the herniation of only a part of the bowel wall. If this hernia is incarcerated/strangulated, it may progress to bowel perforation without obstruction.
  • Hernia of Littre includes a Meckel diverticulum within the hernia sac.
  • Amyand hernia is an inguinal hernia in which the appendix is included within the hernia sac.