title: Rib Fracture Fixation Restores Inspiratory Volume and Peak Flow in a Full Thorax Human Cadaveric Breathing Model.
abstract: BACKGROUND
  Multiple rib fractures cause significant pain and potential for chest wall instability. Despite an emerging trend of surgical management of flail chest injuries, there are no studies examining the effect of rib fracture fixation on respiratory function.
  
  
  OBJECTIVE
  Using a novel full thorax human cadaveric breathing model, we sought to explore the effect of flail chest injury and subsequent rib fracture fixation on respiratory outcomes.
  
  
  METHODS
  We used five fresh human cadavers to generate negative breathing models in the left thorax to mimic physiologic respiration. Inspiratory volumes and peak flows were measured using a flow meter for all three chest wall states: intact chest, left-sided flail chest (segmental fractures of ribs 3 - 7), and post-fracture open reduction and internal fixation (ORIF) of the chest wall with a pre-contoured rib specific plate fixation system.
  
  
  RESULTS
  A wide variation in the mean inspiratory volumes and peak flows were measured between specimens; however, the effect of a flail chest wall and the subsequent internal fixation of the unstable rib fractures was consistent across all samples. Compared to the intact chest wall, the inspiratory volume decreased by 40 ± 19% in the flail chest model (P = 0.04). Open reduction and internal fixation of the flail chest returned the inspiratory volume to 130 ± 71% of the intact chest volumes (P = 0.68). A similar 35 ± 19% decrease in peak flows was seen in the flail chest (P = 0.007) and this returned to 125 ± 71% of the intact chest following ORIF (P = 0.62).
  
  
  CONCLUSIONS
  Negative pressure inspiration is significantly impaired by an unstable chest wall. Restoring mechanical stability of the fractured ribs improves respiratory outcomes similar to baseline values.
authors: Department of Orthopaedics, University of Maryland School of Medicine, R. Adams Cowley Shock Trauma Center, Baltimore, Maryland, USA.
authors: Gerard P
authors: GP
authors: Slobogean
authors: Fischell Department of Bioengineering, Orthopaedic Mechanobiology Laboratory, University of Maryland, College Park, Maryland, USA.
authors: Hyunchul
authors: H
authors: Kim
authors: Fischell Department of Bioengineering, Orthopaedic Mechanobiology Laboratory, University of Maryland, College Park, Maryland, USA.
authors: Joseph P
authors: JP
authors: Russell
authors: Department of Orthopaedics, University of British Columbia, Vancouver, British Columbia, Canada.
authors: David J
authors: DJ
authors: Stockton
authors: Fischell Department of Bioengineering, Orthopaedic Mechanobiology Laboratory, University of Maryland, College Park, Maryland, USA.
authors: Adam H
authors: AH
authors: Hsieh
authors: Department of Orthopaedics, University of Maryland School of Medicine, R. Adams Cowley Shock Trauma Center, Baltimore, Maryland, USA.
authors: Robert V
authors: RV
authors: O'Toole
keywords: Flail Chest; Inspiratory Volume; Operative Stabilization; Peak Flow; Rib Fixation