title: Stress distribution on the thorax after the Nuss procedure for pectus excavatum results in different patterns between adult and child patients.
abstract: OBJECTIVE
  In the Nuss procedure, in which the deformed thorax is forcibly corrected by insertion of correction bars, considerable stresses occur on the patient's thorax. We performed the present study to elucidate how stress patterns on the thorax after this procedure differ between child and adult patients.
  
  
  METHODS
  Eighteen patients with pectus excavatum, constituting a child group (n = 10) and an adult group (n = 8), were included in the study. After a 3-dimensional computer-assisted design model was produced with computed tomographic data from each patient, simulation of the Nuss procedure was performed on the model. Then the stresses occurring on each thorax were calculated using the finite element method. The stresses were compared between the child and adult groups in terms of intensity on each rib and the distribution patterns over the whole thorax.
  
  
  RESULTS
  With all 12 ribs, significantly greater stress occurred in the adult group than stress in the child group. Although the stresses occurring on the thorax demonstrated concentrated patterns in the child group, widely distributed patterns were observed in the adult group.
  
  
  CONCLUSIONS
  The stresses that occur on the thorax after the Nuss procedure take different patterns between children and adults in terms of intensity and distribution. The differences should be taken into consideration in managing postoperative pain after the Nuss procedure.
authors.affiliation: Department of Plastic and Reconstructive Surgery, School of Medicine, Keio University, Tokyo, Japan.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Nagasao
authors.forename: Junpei
authors.initials: J
authors.lastname: Miyamoto
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Tamaki
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ichihara
authors.forename: Hua
authors.initials: H
authors.lastname: Jiang
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Taguchi
authors.forename: Ryohei
authors.initials: R
authors.lastname: Yozu
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Nakajima
mesh_terms: D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D005660:Funnel Chest / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008954:Models, Biological; D009984:Orthopedic Fixation Devices; D010149:Postoperative Pain / Q000209:etiology; D013314:Stress, Mechanical; D019616:Thoracic Surgical Procedures / Q000009:adverse effects / Q000295:instrumentation; D013909:Thorax / Q000503:physiopathology*; D014057:Tomography, X-Ray Computed