Indirect Inguinal Hernia

A mass on the left side of the scrotum (A) was the presenting complaint of a 7-year-old boy. The mass increased in size when the child cried, strained or coughed. Physical examination showed a left scrotal mass that was reducible with manipulation when the child was lying down. The left spermatic cord was found to be thickened-the "silk" sign. A diagnosis of left indirect inguinal hernia was made.

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

In infants, the incidence of indirect inguinal hernia is 1% to 2%, with a male to female ratio of 9:1. The incidence is higher in premature infants, and the risk is greater in children with increased intra-abdominal pressure.

An indirect inguinal hernia may become incarcerated (B); this condition presents with a painful mass that is irreducible. The overlying skin may be erythematous. Vomiting, abdominal distention, and radiographic evidence of a bowel obstruction confirm the diagnosis. An incarcerated hernia occurs most often during the first 6 months of life. Occasionally, strangulation may occur, and infarction of the small bowel, testis, or ovary may result.

Surgical repair of the hernia should be carried out electively shortly after diagnosis. There is controversy about whether the contralateral groin should be explored. Most surgeons recommend bilateral inguinal exploration in all boys younger than 1 year, in patients with conditions associated with an increased risk of an inguinal hernia, and in all girls younger than 2 years.