Preoperative ultrasound and intraoperative findings of inguinal hernias in children: A prospective study of 642 children.

Background/purpose: Preoperative sonographic studies of the groins have become a routine evaluation of inguinal hernia in children. Its value is not only to confirm the clinical diagnosis, but also to accurately assess the opposite side and to prevent an unnecessary exploration or additional operation at a later stage. The purpose of this study is to report more definitive criteria of inguinal hernias (IH) and patent process vaginalis (PPV) established from 1,284 groin examinations.

Methods: From January 1999 to October 2000 the authors compared prospectively the sonographic dimensions of the inguinal canal to the operative findings as reported by the surgeons (blinded to the results) for 642 pediatric patients (ages 1 to 176 months) undergoing inguinal hernia repairs.

Results: A normal inguinal canal was found at operation when a preoperative sonographic groin width of 3.6 +/- 0.8 mm, on average, was detected. A PPV was found when a groin width of 4.9 +/- 1.1 mm was detected. A full hernia was found when a groin width of 7.2 +/- 2.0 mm was detected. A large hernia was found when a groin width of 12.8 +/- 3.6 mm was detected, and a hydrocele was found along with a groin width of 4.8 +/- 2.2 mm.

Conclusions: Establishing accurate sonographic criteria for inguinal hernia and patent processus vaginalis is an important tool for the pediatric surgeon to plan the approach before groin surgery.