Preoperative sonography of the inguinal canal prevents unnecessary contralateral exploration.

The need for contralateral inguinal exploration in children during unilateral inguinal hernia repair remains controversial. We questioned whether an elective preoperative sonographic examination of the contralateral inguinal canal was accurate enough to prevent unnecessary exploration of the asymptotic side. Sonography (US) of the groins was performed randomly in 200 out of 600 patients awaiting unilateral hernia repair over a 1.5-year period during 1990-1991. The patients and their medical records were reviewed in 1994, 3-4 years following surgery. Four hundred infants and children underwent unilateral inguinal hernia repair without preoperative US, based on the clinical diagnosis (group I). Of the remaining 200, 160 (group II)_ had the clinical diagnosis confirmed by US. Forty patients with US evidence of a contralateral hernia or hydrocele (group III) were excluded from the study. At follow-up after 3-4 years, 26 patients in group I presented with a hernia in the opposite groin 2 weeks to 2 years following surgery. The incidence of a subsequent contralateral hernia in patients under 1 year, 1-2 years, and older than 2 years was 7.3%, 9.6%, and 4.5%, respectively. None of the patients in group II presented with a clinically evident hernia during the follow-up period. These findings suggest that US is a readily available, non-invasive, and accurate method of preoperative evaluation of the groins. Our policy of contralateral exploration based on the US findings was shown to be reliable in preventing unnecessary surgical exploration of the unaffected inguinal canal.