Second repair of pediatric inguinal hernia: A longitudinal cohort study

Background: The objective of this nationwide observational study was to report the rate and risk factors for the second repair after pediatric inguinal herniorrhaphy. Materials and Methods: Children born from 1998 to 2005 were chosen from a cohort of 1,000,000 cases, which were randomly selected from an insured population of 23 million people in Taiwan (Longitudinal Health Insurance Database 2005). We identified all hernia repairs in the period of 1998–2012 for the sample population and then used a Cox proportional hazards regression model to analyze the risk factors for the second repair after pediatric inguinal herniorrhaphy. Results: The total sample population comprised 79,820 children, with a male-to-female ratio of 4.27:1. During a mean observation period of 11.4 ± 2.2 years, 3339 (4.18%) of the children in the sample population received primary inguinal hernia repair. Of the 251 children (7.52%) who underwent a second repair, 220 were boys (8.13%) and 31 were girls (4.9%); 244 (8.62%) underwent primary unilateral hernia repair, and 7 (1.38%) underwent primary bilateral hernia repair. Considering that bilateral hernia involves unilateral hernia on two sides, the expected recurrence rate after primary unilateral hernia repair was calculated as 0.69%. The calculated rates for late occurrence of contralateral hernia after primary unilateral hernia repair were 11.04%, 7.73%, and 3.28% for children aged 0–1, 1–4, and >4 years, respectively. Significant risk factors for second hernia repair were age at first primary hernia repair and unilateral hernia (P < 0.001). Gender and prematurity were not risk factors for second hernia repair. Conclusions: The second repair rate after primary unilateral or bilateral hernia repair was 7.52%. The only risk factor that predicted the second repair was age of