Background: Routine contralateral groin exploration in infants and children with a clinically detected inguinal hernia is the subject of much debate. The detection of a patent processus vaginalis by transinguinal laparoscopy has proven advantageous. However, controversy remains regarding the true incidence of a contralateral patent processus vaginalis as well as which of these will actually develop into a clinically apparent hernia.

Methods: From January 1997 through December 1999, 358 infants and children (aged 1 to 157 months, mean 32) were treated in the three University of Oklahoma teaching hospitals in Tulsa, Oklahoma, for inguinal hernia. The findings at laparoscopic exploration of the contralateral side were recorded to determine the incidence of contralateral patency as it relates to a child’s age, gender, and side of the initial clinical diagnosis.

Results: The overall incidence of a patent processus vaginalis on contralateral examination was 33% (117 of 358). All patent processus vaginalis were repaired. Bilateral inguinal hernia was significantly more common in younger patients (present in 50% if less than 1 year, 45% if less than 2 years, 37% if less than 5 years, and 15% if greater than 5 years of age; P <0.05). In boys, the incidence was 49%, 45%, and 32% in those under 1 year of age, under 2 years of age, and in total, respectively. In girls, the incidence was 59%, 50%, and 37% in those under 1 year of age, under 2 years of age, and in total, respectively. The side of the clinically detected hernia did not influence the laparoscopic findings of a contralateral hernia with 30% (50 of 169) positive findings on left inguinal exploration versus 31% (28 of 90) positive findings on right inguinal exploration.

Conclusions: The high incidence of a contralateral patent processus vaginalis warrants routine laparoscopic exploration in infants and children undergoing unilateral inguinal hernia repair, especially those less than 5 years of age. The use of transinguinal laparoscopic explorations avoids unnecessary open exploration in 66% of infants and children undergoing inguinal hernia repair.