title: Incidence of metachronous contralateral inguinal hernias in children following unilateral repair - A meta-analysis of prospective studies.
abstract: OBJECTIVE
  The objective of this review was to systematically evaluate the incidence of a metachronous contralateral inguinal hernia (MCIH) in children with unilateral inguinal hernia and therefore to propose or to reject routine contralateral groin exploration.
  
  
  METHODS
  Electronic searches restricted to prospective studies with a minimal follow-up of 1year included MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials.
  
  
  RESULTS
  Six studies involving 1669 children were included. Overall MCIH was 6% (95% CI from 4% to 8%). The odds for MCIH development were significantly larger in children with an initial left-sided hernia (OR 2.66 with 95% CI from 1.56 to 4.53) and in children with open contralateral processus vaginalis (CPV) (OR 4.17 with 95% CI from 1.25 to 13.9).
  
  
  CONCLUSIONS
  The overall incidence of MCIH following unilateral inguinal hernia repair in children is 6%. Initial left-sided hernia (8.5%) and open CPV (13.8%) are risk factors for MCIH development. Female gender (8.2%) and younger age (<1year) (6.9%) non-significantly increase the risk of MCIH.
authors.affiliation: Emergency Department, Hospital Baden, Baden, Switzerland.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Wenk
authors.affiliation: Epidemiology, Biostatistics, and Prevention Institute (EBPI) at the University of Zurich, Zürich, Switzerland.
authors.forename: Beate
authors.initials: B
authors.lastname: Sick
authors.affiliation: University of Zurich, Zürich, Switzerland.
authors.forename: Tom
authors.initials: T
authors.lastname: Sasse
authors.affiliation: Pediatric Surgery, University Children's Hospital of Zurich, Zürich, Switzerland.
authors.forename: Ueli
authors.initials: U
authors.lastname: Moehrlen
authors.affiliation: Pediatric Surgery, University Children's Hospital of Zurich, Zürich, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Meuli
authors.affiliation: Pediatric Surgery, University Children's Hospital of Zurich, Zürich, Switzerland. Electronic address: rnvuille@gmail.com.
authors.forename: Raphael N
authors.initials: RN
authors.lastname: Vuille-dit-Bille
mesh_terms: D002648:Child; D006552:Hernia, Inguinal / Q000150:complications* / Q000601:surgery*; D006801:Humans; D007223:Infant; D012307:Risk Factors
keywords: Contralateral; Incidence; Inguinal hernia; Metachronous