title: A biomechanical study of relationship between sternum defect patterns and thoracic respiration.
abstract: BACKGROUND
  Various types of sternum defects are produced after the removal of thoracic tumors involving the sternum. The present study aims to elucidate the relationship between the defect patterns and their effects on thoracic respiration.
  
  
  METHODS
  Ten sets of finite element models were produced simulating thoraces of 10 persons and termed normal models. With each of the 10 normal models, the sternum was removed in six different ways to produce new models termed defect models. Defect models were categorized into hemi-superior (H-S), hemi-inferior (H-I), hemi-whole length (H-W), bilateral-superior (B-S), bilateral-inferior (B-I), and bilateral-whole length (B-W) defect types, depending on the locations of the defects. Respiratory movement was dynamically simulated with these models. The volume change the thoraces present during respiration was measured to evaluate the effectiveness of thoracic respiration. This value - defined as ΔV - was calculated and was compared between normal and defect models.
  
  
  RESULTS
  With H-W and B-W type models, ΔV dropped to around 20% of normal values. With H-S and B-S type models, ΔV dropped to around 50% of normal values. With H-I and B-I type models, ΔV presented values almost equivalent to those of normal models.
  
  
  CONCLUSIONS
  Effectiveness of thoracic respiration is seriously impaired when the whole length of the sternum is absent. Reconstruction of the defect is essential for these cases. However, since the upper part of the sternum is most important for effective thoracic respiration, priority should be placed on the upper part in performing reconstruction.
authors.affiliation: a Department of Plastic and Reconstructive Surgery , Keio University Hospital , Tokyo , Japan.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Nagasao
authors.affiliation: a Department of Plastic and Reconstructive Surgery , Keio University Hospital , Tokyo , Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Kasai
authors.affiliation: a Department of Plastic and Reconstructive Surgery , Keio University Hospital , Tokyo , Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Shimizu
authors.affiliation: a Department of Plastic and Reconstructive Surgery , Keio University Hospital , Tokyo , Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Sakamoto
authors.affiliation: b Department of Plastic and Reconstructive Surgery , Kawasaki Municipal Hospital , Kawasaki , Japan.
authors.forename: Asako
authors.initials: A
authors.lastname: Hatano
authors.affiliation: c Department of Plastic Surgery , Kinki University Hospital , Tokyo , Japan , and.
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Morotomi
authors.affiliation: a Department of Plastic and Reconstructive Surgery , Keio University Hospital , Tokyo , Japan.
authors.forename: Hisao
authors.initials: H
authors.lastname: Ogata
authors.affiliation: a Department of Plastic and Reconstructive Surgery , Keio University Hospital , Tokyo , Japan.|d Department of Plastic Surgery , The Second Military Medical University, Chang Zheng Hospital , Shanghai , Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kishi
mesh_terms: D001696:Biomechanical Phenomena / Q000502:physiology; D003198:Computer Simulation; D055119:Elastic Modulus / Q000502:physiology; D020342:Finite Element Analysis; D006801:Humans; D012119:Respiration; D013249:Sternum / Q000503:physiopathology* / Q000601:surgery*; D013899:Thoracic Neoplasms / Q000601:surgery*; D014057:Tomography, X-Ray Computed
keywords: Defect; finite element analysis; function, respiration; simulation; sternum; thorax