Ultrasonographic Diagnosis of Potential Contralateral Inguinal Hernia in Children

Background/Purpose: Several methods have been advocated to minimize the frequency of negative exploration of the contralateral side in children presenting with a unilateral congenital inguinal hernia (CIH). This study was carried out to investigate the accuracy of ultrasonography in recognition of an unapparent CIH or a patent processus vaginalis (PPV) in the contralateral side in children presenting with a unilateral CIH Materials and Methods: From November 2003 to March 2005, 173 children presented with a clinically apparent unilateral CIH. Their ages ranged between 1 week and 24 months (mean, 21.8 weeks). The contralateral inguinal region was examined by ultrasound using a 7.5 MHz transducer. Presence of potential CIH was considered if one or more of the following features were noted: 1. A well defined viscous is observed in the inguinal canal; 2. A cystic pattern is seen at the internal ring of inguinal canal; 3. The presence of a PPV that enlarges when abdominal pressure increases 4. The PPV contains moving material without enlargement. Only patients with positive ultrasonographic findings undergone exploration of the contralateral inguinal canal at the same session following repair of the clinically detected hernia. Follow up ranged from six to eleven months. Results: Positive ultrasonographic findings were noted in 31 of the 173 patients (17.9%). Twenty seven of the 31 patients (87.1%) proved to have a PPV or a definite hernial sac, while 4 (12.9% false positive) showed no hernial sac on exploration. Two of the 142 patients who had negative ultrasonographic findings at the contralateral side, developed an inguinal hernia after 4 and 6 months respectively (1.4% false negative). The sensitivity and the specificity of utrasonography in detecting a potential CIA or PPV in the contralateral side was 87.1% and 98.6% respectively. The positive and negative predictive values of this diagnostic tool were 93.1% and 97.2% respectively, and the accuracy rate reached 96.5%. Conclusions: 1. Ultrasound is a non-invasive and relatively accurate method to determine which patient should have exploration of the contralateral side; 2. Routine contralateral inguinal exploration is not recommended anymore.