title: Esophageal length: esophageal manometry remains superior to mathematical equations.
abstract: OBJECTIVE
  Many mathematical equations based on height have been developed to estimate the esophageal length (EL) in children. The aim of this study was to confirm whether the preexisting and most frequently used equation by Strobel et al is accurate in calculating the EL in our pediatric population. Our secondary goal was to evaluate whether a new formula could be developed using our nonsurgical and surgical populations' data for the correlation between patients' height and measured EL by esophageal manometry (EM).
  
  
  METHODS
  From 2000 to 2009, 116 children between the ages of 3 and 18 years without previous esophageal surgery underwent EM (n = 31) at the Montreal Children's Hospital. During the same period, 55 EMs were performed on 34 children with a previous history of esophageal surgery. For both groups, we collected the following data: height, EL calculated by the Strobel formula, and EL measured by EM.
  
  
  RESULTS
  The Strobel equation was inaccurate in predicting the EL. The calculated EL was 3.0 ± 0.32 cm longer than the EM measurements (P < 0.001). The height (H) of nonsurgical children was found to be highly predictive of the lower esophageal sphincter location (L), and the derived linear regression equation is L = 0.216 (H) + 7.13 [r² = 0.85].
  
  
  CONCLUSIONS
  This study confirmed that the Strobel formula is not sufficiently accurate to predict EL in the pediatric population that is between 3 and 18 years old. A correlation exists between height and esophageal sphincter location position. If EM is unavailable, the use of a new mathematical equation like ours can be considered.
authors.affiliation: Division of Pediatric Gastroenterology, Department of Pediatrics, Montreal Children's Hospital, McGill University, Montreal, Quebec, Canada. Brigitte.Moreau@mail.mcgill.ca
authors.forename: Brigitte
authors.initials: B
authors.lastname: Moreau
authors.forename: Sandra
authors.initials: S
authors.lastname: Kambites
authors.forename: Dominique
authors.initials: D
authors.lastname: Lévesque
mesh_terms: D000293:Adolescent; D001827:Body Height; D057785:Catheters; D002648:Child; D002675:Child, Preschool; D004566:Electrodes; D049630:Esophageal Sphincter, Lower; D050782:Esophageal pH Monitoring; D004947:Esophagus; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis; D006801:Humans; D006863:Hydrogen-Ion Concentration; D016014:Linear Models; D008297:Male; D008365:Manometry / Q000379:methods*; D055641:Mathematical Concepts; D015203:Reproducibility of Results