title: Relationship between locations of rib defects and loss of respiratory function - a biomechanical study.
abstract: OBJECTIVE
  The present study elucidates the relationship between the locations of rib defects and loss of respiratory function.
  
  
  METHODS
  Ten sets of three-dimensional finite element models were produced from computed tomography data of 10 persons and categorized as normal type models. These models were modified by removing part of the ribs, and the resultant models were categorized as defect type models. Varying the location of the defects, six types of defect model were produced from each of the 10 normal models; the defects were made on the anterior-superior, anterior-inferior, lateral-superior, lateral-inferior, posterior-superior, and posterior-inferior regions of the thorax. To simulate respiration, contracture forces were applied to nonlinear springs modeling respiratory muscles for each of the normal and defect models. Difference in volume of the thoracic cavity between inspiration and expiration phases was viewed as the indicator of respiratory function and was defined as ΔV. The values of ΔV were compared between normal type models and their corresponding defect type models.
  
  
  RESULTS
  Among the six types of defect, the degree of functional loss was greatest with those defects on the lateral-inferior part of the thorax, where ΔV of the affected side hemithorax drops to 38 to 45% of normal values, whereas ΔV was 62 to 88% with other defect models.
  
  
  CONCLUSIONS
  Thoraces that have defects on their lateral-inferior regions present lower respiratory functioning than thoraces with other defect locations. Hence, in treating clinical cases where defects are expected to occur in this region, effort should be made to minimize the area of the defect.
authors.affiliation: Department of Reconstructive Surgery, Keio University Hospital, Tokyo, Japan.
authors.forename: Asako
authors.initials: A
authors.lastname: Hatano
authors.affiliation: Department of Plastic and Reconstructive Surgery, Keio University Hospital, Tokyo, Japan.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Nagasao
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Tokai University Hospital, Isehara, Japan.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Cho
authors.affiliation: Department of Reconstructive Surgery, Keio University Hospital, Tokyo, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Shimizu
authors.affiliation: Department of Mechanical Engineering, Keio University, Tokyo, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Takano
authors.affiliation: Department of Plastic Surgery, The Japanese National Center for Child Growth and Development, Tokyo, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Kaneko
authors.affiliation: Department of Reconstructive Surgery, Keio University Hospital, Tokyo, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kishi
mesh_terms: D001696:Biomechanical Phenomena; D003196:Computer Graphics; D003198:Computer Simulation; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008953:Models, Anatomic; D010027:Osteotomy; D012119:Respiration; D012132:Respiratory Muscles / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012272:Ribs / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D025321:Surgery, Computer-Assisted; D014057:Tomography, X-Ray Computed