In-flight Clotting: Is It Something in the Air?

During the last few weeks of gestation or shortly after birth, the layers of the processus vaginalis normally fuse together and obliterate the entrance to the inguinal canal in the vicinity of the internal inguinal ring. An indirect hernia results from a failure of fusion of the processus vaginalis; the bowel subsequently descends through the inguinal canal.

The incidence of indirect inguinal hernia in infants is 1% to 2%; the male to female ratio is 9:1. The incidence is higher in premature infants and those with connective tissue disorders, bladder exstrophy, and increased intra-abdominal pressure. There is a familial tendency for hernia formation. An indirect inguinal hernia is more common on the right side, because of the later descent of the right testis and delayed obliteration of the processus vaginalis. Sixty percent of indirect inguinal hernias are on the right, 25% on the left, and 15% bilateral.

Incarcerated indirect inguinal hernia is a common cause of intestinal obstruction in infants and young children. The rate of incarceration is significantly higher in premature infants and those in the first year of life than in older children.

An incarcerated hernia presents with a painful irreducible mass in the groin or scrotum (A). The overlying skin may be erythematous. Vomiting, abdominal distention, and radiographic evidence of a bowel obstruction with gas in the groin or scrotum (B) confirm the diagnosis. An incarcerated hernia may strangulate in a matter of hours, resulting in infarction of the contained viscus and the ipsilateral gonad.

Unless the child appears toxic or shows signs of peritonitis, a manual reduction of the incarcerated hernia with the child sedated should be attempted. Immediate surgery is indicated if the incarcerated hernia is irreducible manually.