title: [Factors related to the olive size in patients with hypertrophic pyloric stenosis].
abstract: BACKGROUND
  The pyloric "olive" (PO) is the result of the anomalous growth of the pyloric muscle among patients with pyloric stenosis (PS). It frequently is unexpectedly large, or some other times surprisingly small, and those variations in size have been difficult to explain.
  
  
  METHODS
  We measured the PO in 145 consecutive patients with PS during the operation, and then we classified them as small if their length was less than 20 mm, medium if 20 to 30 mm, or large if more than 30 mm; several variables were analyzed by mean of the chi square or Spearman rho tests.
  
  
  RESULTS
  Six cases were excluded due to an unclear total length record of the PO. The PO size was classified as small in 19 (13.7%), medium in 71 (51%) and large in 49 (35.3%). The PO size did not associate with gender, way of birth, the presence of jaundice, constipation or any specific blood group or Rh factor, and it did not correlate with birth weight or month and gestational order either. Medium and large PO were more frequently palpated than smaller (94-100% vs. 83%, p = 0.009); PO size correlated with the duration of the history of vomiting (CQ 0.267, p = 0.002), child's age (CQ 0.243, p = 0.005) and weight at operation (CQ 0.190, p = 0.048). A daily weight loss surpassing 5 g was more commonly found among small PO (p = 0.038).
  
  
  CONCLUSIONS
  In more than a third of the PS patients, PO is unexpectedly large, and in one of every seven it is surprisingly small. The bigger PO size associates with a longer disease, and with older and heavier patients, which probably is explained by a slighter clinical course. A small PO is more difficult to palpate during clinical evaluation.
authors.affiliation: Hospital de Especialidades 1, Centro Médico Nacional Noroeste, IMSS, Ciudad Obregón, Sonora. alejandro.gomezal@imss.gob.mx
authors.forename: Alejandro V
authors.initials: AV
authors.lastname: Gómez-Alcalá
mesh_terms: D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D046248:Pyloric Stenosis, Hypertrophic / Q000473:pathology* / Q000601:surgery; D011708:Pylorus / Q000473:pathology*