Risk factors for contralateral metachronous indirect inguinal hernia in children with unilateral inguinal hernia

Abstract

© JOURNAL OF THE MEDICAL ASSOCIATION OF Thailand | 2019 Background: The repair of indirect inguinal hernia is a common operation among pediatric surgeons. The incidence of inguinal hernia in children ranging from 0.8% to 4.4%. After unilateral repair of the inguinal hernia, the incidence of a contralateral inguinal hernia is about 6%. Objective: To identify the risk factors of metachronous contralateral indirect inguinal hernia (MCIH). Materials and Methods: A retrospective cohort study of the indirect inguinal hernia patients (ICD-10 code K40.9) was performed. Patients having bilateral inguinal hernia at the initial presentation were excluded. The patient between 0 and 15 years old visiting the authors’ institute between January 2007 and December 2014 were included. The data collected including gender, age at presentation, birthweight, gestational age, initial side of indirect inguinal hernia, history of incarceration, post-operative complication, recurrence, comorbidity, and presence of MCIH as the outcome of the present study. Results: Five hundred seventy-five indirect inguinal hernia patients’ data were collected. Fifty-nine patients were excluded due to bilateral indirect inguinal hernias at presentation. Five hundred sixteen patients were included for final analysis. Incarceration in the initial side was found in 23%. The MCIH was found in 7.9% with a mean follow-up time of 21 months (maximum time 124 months). The multivariable analysis of the factors associated with MCIH clustering by gender was performed and the significant risk factors were initial left side hernia (risk ratio [RR] 1.27, p=0.011, number needed to treat [NNT] 50), age less than six months (RR 1.04, p=0.001, NNT 200), underlying heart disease (RR 2.50, p<0.001, NNT 8), and lung disease (RR 1.39, p=0.007, NNT 20). Conclusion: The risk factors of the MCIH in the present study were initial left side hernia, age less than six months, and underlying heart and lung diseases clustering by gender. The history of risk factors combined with the definite physical examination and investigation aided in the judgement for contralateral inguinal exploration.