title: Incidence of pediatric metachronous contralateral inguinal hernia in children aged ≥1 year.
abstract: BACKGROUND
  The management of the contralateral asymptomatic side when a child with initial unilateral inguinal hernia undergoes herniorrhaphy continues to be controversial. Age less than 6 months at initial herniorrhaphy is considered as a high risk factor of the occurrence of metachronous contralateral inguinal hernia (MCIH). We performed herniorraphy for patients ≥1 year with initial unilateral hernia at one-day-set outpatient-surgery department without any intervention of contralateral groin. In this study, we reviewed the characteristics of development of MCIH in this condition and discuss the management strategies of MCIH.
  
  
  METHODS
  The subjects of this study were children who were treated at our outpatient-surgery department from January 2006 to December 2006. A total of 2129 patients with initial unilateral hernia and aged ≥1 year underwent an ipsilateral herniorhhaphy only. Patients were followed up for the development of MCIH to 60 months. The Chi-square test was used for intergroup comparison, a level of P<0.05 was considered as statistically significant.
  
  
  RESULTS
  Among these children 1341 (63.0%) were obtained 60 months follow-up data, 1146 (85.5%) were boys and 195 (14.5%) were girls. MCIH developed in 70 (5.2%) patients, 61 were boys and 9 were girls. In 570 patients aged 12-23 months, 43 developed MCIH (7.5%); in 564 patients aged 24-59 months, 21 developed MCIH (3.7%); and in 207 patients ≥60 months, 6 patients developed MCIH (2.9%), the difference between these groups was highly significant (P=0.004). In male patients, 30 right-sided MCIHs occurred after 423 initial left-sided herniorrhaphies (7.1%) and 31 left-sided MCIHs occurred after 723 initial right-sided herniorrhaphies (4.3%), difference between these two groups was significant (P=0.041). Seventy-seven percent of the MCIHs occurred within 1 year, 94% occurred within 2 years after initial herniorraphy.
  
  
  CONCLUSIONS
  As the overall incidence of MCIH in patients aged ≥1 year was 5.2%, routine contralateral groin exploration is not suggested. Transinguinal laparoscopy could be considered as an alternative of conventional "wait and see" policy, especially in patients less than 2 years or left-sided initial unilateral inguinal hernia. If "wait and see" policy is adopted, patients should be closely followed up for 2 years.
authors.affiliation: Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China.
authors.forename: Jin-Hu
authors.initials: JH
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Jin-Fa
authors.initials: JF
authors.lastname: Tou
authors.forename: Shou-Jiang
authors.initials: SJ
authors.lastname: Huang
authors.forename: Wei-Guang
authors.initials: WG
authors.lastname: Liu
authors.forename: Qi-Xing
authors.initials: QX
authors.lastname: Xiong
authors.forename: Zheng-Yan
authors.initials: ZY
authors.lastname: Zhao
mesh_terms: D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D005260:Female; D006552:Hernia, Inguinal / Q000453:epidemiology* / Q000601:surgery*; D059685:Herniorrhaphy / Q000379:methods*; D006801:Humans; D015994:Incidence; D007223:Infant; D010535:Laparoscopy; D008297:Male; D012307:Risk Factors; D016896:Treatment Outcome