Prediction of contralateral inguinal hernias in children: a prospective study of 357 unilateral inguinal hernias

PURPOSE: Previously, we established a pre-operative risk scoring system to predict contralateral inguinal hernia in children with unilateral inguinal hernias. The current study aimed to verify the usefulness of our pre-operative scoring system. METHODS: This was a prospective study of patients undergoing unilateral inguinal hernia repair from 2006 to 2009 at a single institution. Gender, age at initial operation, birth weight, initial operation side, and the pre-operative risk score were recorded. We analyzed the incidence of contralateral inguinal hernia, risk factors, and the usefulness of our pre-operative risk scoring system. The follow-up period was 36 months. We used forward multiple logistic regression analysis to predict contralateral hernia. RESULTS: Of the 372 patients who underwent unilateral hernia repair, 357 (96.0 %) were completely followed-up for 36 months, and 23 patients (6.4 %) developed a contralateral hernia. Left-sided hernia (OR = 5.5, 95 %, CI = 1.3–24.3, p = 0.023) was associated with an increased risk of contralateral hernia. The following covariates were not associated with contralateral hernia development: gender (p = 0.702), age (p = 0.215), and birth weight (p = 0.301). The pre-operative risk score (cut-off point = 4.5) of the patients with a contralateral hernia was significantly higher, compared with the patients without a contralateral hernia using the area under the receiver operating characteristic curve (p = 0.024). CONCLUSIONS: Using multivariate analysis, we confirmed usefulness of our pre-operative scoring system and initial side of the inguinal hernia, together, for the prediction of contralateral inguinal hernia in children.