Ultrasound assessment of the contralateral groin in infants with unilateral inguinal hernia.

Sonographic and operative findings in both groins of 23 infants presenting with a unilateral inguinal hernia were compared in a prospective study. Ultrasound accurately confirmed the presence of a hernia on the affected side in all infants but provided no useful additional diagnostic information. Ultrasound examination of the unaffected side was less accurate. Surgical exploration revealed the presence of a patent processus vaginalis (PPV) in 18 cases and its absence in five. Ultrasound was found to be accurate in only 15 out of the 23 cases with four false positive and four false negative results. This yielded an accuracy of 65%, a sensitivity of 78% and a specificity of only 20%. It is concluded that ultrasound cannot at present be used alone to plan the management of the contralateral groin, especially as the majority of children who do have a PPV will never develop an inguinal hernia.