title: Meta-analysis of the risk of metachronous hernia in infants and children.
abstract: BACKGROUND
  Inguinal herniorrhaphy is the most common general surgical procedure performed in children. The presence of a contralateral patent processus vaginalis forms the basis of the recommendation for contralateral exploration in patients undergoing unilateral herniorrhaphy. However, a patent processus vaginalis does not necessarily go on to become a clinically apparent inguinal hernia.
  
  
  METHODS
  All published pediatric series, in which patients underwent unilateral inguinal hernia repair and were evaluated for the development of a metachronous hernia, were included. The incidence of and risk factors associated with development a metachronous hernia were evaluated with meta-analysis.
  
  
  RESULTS
  There were 15,310 patients ranging in age from birth to 16 years, including premature infants. Of these, 1,062 patients (7%) developed a metachronous hernia. Gender and age were not risk factors. There was an 11% risk of metachronous hernia if the original hernia was on the left side, a risk that was 50% greater than if the original hernia was on the right. Of patients who developed a metachronous hernia, 90% did so within 5 years. The complication rate of metachronous hernia was 0.5%.
  
  
  CONCLUSIONS
  There is no role for routine contralateral groin exploration. High-risk infants and children, especially those who undergo left inguinal herniorrhaphy, may benefit from contralateral groin exploration. If a patent processus vaginalis is found, it should be ligated. Patients who do not undergo contralateral groin exploration should be followed up for 5 years.
authors.affiliation: Department of Surgery, Baylor College of Medicine, Houston, Texas 77030, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Miltenburg
authors.forename: J G
authors.initials: JG
authors.lastname: Nuchtern
authors.forename: T
authors.initials: T
authors.lastname: Jaksic
authors.forename: C A
authors.initials: CA
authors.lastname: Kozinetz
authors.forename: M L
authors.initials: ML
authors.lastname: Brandt
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D006552:Hernia, Inguinal / Q000150:complications* / Q000601:surgery*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008026:Ligation; D012306:Risk