Chapter 47: Inguinal Hernia

High-Yield Facts

• Most inguinal hernias are asymptomatic and are managed by referral to a pediatric surgeon for elective management.

• Incarcerated hernias are best reduced by the taxis method.

• Inability to reduce an inguinal hernia requires emergent referral to a surgeon.

Inguinal hernias are among the most common congenital conditions in children. They have a reported incidence of 0.8% to 4.4% in children¹ and 3.5% to 5% in full-term newborns² with a 10-fold increase in males versus females.³ Premature infants of less than 36 weeks gestational age have a rate approaching 7%,⁴ with the highest rate seen in infants less than 28 weeks of gestational age or with a birth weight less than 1000 g.² Ten percent of these may become incarcerated before 1 year of age,⁵ with the greatest risk occurring during the first 6 months of life.⁶

Anatomy

Hernias in the groin can be divided in to three types: direct, indirect, and femoral. An indirect inguinal hernia occurs when abdominal contents pass through the internal ring and then traverse the inguinal canal into the scrotum. Congenital inguinal hernias, by far the most common, are indirect by definition⁷ due to a processus vaginalis that fails to fully close. Direct inguinal hernias are rare in children and occur when there is a weakness in the abdominal musculature allowing intestine to protrude into the inguinal canal. Femoral hernias pass into the femoral canal and not into the scrotum or labia.

There is an outpouching of the peritoneum into the inguinal canal by the processus vaginalis about the third month of gestation. In males, the testes descend into the scrotum during the seventh month of gestation, the left usually preceding the right. The processus vaginalis will remain partially patent in approximately 70% of term male infants in the first 2 weeks after birth but will be virtually obliterated by the third week, again the left before the right.⁸ This probably explains why a majority of inguinal hernias are found on the right side (60%) compared with 30% on the left and 10% bilaterally.⁹

The processus vaginalis does not become as deep in females since ovarian descent is restricted by the ovarian ligament. The extension of the processus vaginalis past the inguinal canal is referred to as the canal of Nuck in females. An indirect hernia can occur if it remains patent.

As opposed to a hernia where intestine enters the inguinal canal, a hydrocele may occur when the processus vaginalis narrows to the point that only fluid can pass (communicating). The hydrocele is noncommunicating when fluid is trapped after the processus closes.

Signs and Symptoms

In the first year of life, inguinal hernias most often present as a bulge in the groin, scrotum, or labia. The bulge may come and ...