title: Age-related probability of contralateral processus vaginalis patency in children with unilateral inguinal hernia.
abstract: OBJECTIVE
  Contralateral groin exploration with closure of a patent processus vaginalis (PPV) in children with a unilateral inguinal hernia remains controversial. We aimed to generate precise, age-related probabilities of patency of the contralateral processus vaginalis (PV) in infants with a unilateral inguinal hernia to guide practice.
  
  
  METHODS
  Retrospective review of all unilateral laparoscopic inguinal hernia repairs in 5 years to determine patency of contralateral PV. Using logistic binomial regression, age-adjusted odds ratio (OR), probability of contralateral PPV and number needed to explore (NNE) in order to close all PPVs were estimated.
  
  
  RESULTS
  Data from 331 children [262 male, median 3.8 months corrected gestational age (CGA)] were analysed; 160 (48 %) had a contralateral PPV. In the regression model, CGA is linearly related to log[OR] such that for each month increase in CGA, the log[OR] of having a contralateral PPV decreased by 0.017 ± 0.006 (mean ± SEM; p = 0.005). Gender and side of hernia had no significant effect. The probability of contralateral PPV is 50 % (NNE = 2) at 8 m CGA, 33 % (NNE = 3) at 49 m and 25 % (NNE = 4) at 72 m.
  
  
  CONCLUSIONS
  These data contribute to our knowledge of the natural history of the PV and may help guide the need for contralateral groin exploration in infants with inguinal hernia.
authors.affiliation: Surgery Unit, Department of Paediatric Surgery, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK. nigel.hall@ucl.ac.uk
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Hall
authors.forename: Wonyong
authors.initials: W
authors.lastname: Choi
authors.forename: Agostino
authors.initials: A
authors.lastname: Pierro
authors.forename: Simon
authors.initials: S
authors.lastname: Eaton
mesh_terms: D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D005260:Female; D006552:Hernia, Inguinal / Q000150:complications* / Q000601:surgery*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007264:Inguinal Canal / Q000002:abnormalities* / Q000601:surgery*; D008297:Male; D012189:Retrospective Studies