title: Adolescent Idiopathic Scoliosis Thoracic Volume Modeling: The Effect of Surgical Correction.
abstract: BACKGROUND
  Scoliosis has been shown to have detrimental effects on pulmonary function, traditionally measured by pulmonary function tests, which is theorized to be correlated to the distortion of the spine and thorax. The changes in thoracic volume with surgical correction have not been well quantified. This study seeks to define the effect of surgical correction on thoracic volume in patients with adolescent idiopathic scoliosis.
  
  
  METHODS
  Images were obtained from adolescents with idiopathic scoliosis enrolled in a multicenter database (Prospective Pediatric Scoliosis Study). A convenience sample of patients with Lenke type 1 curves with a complete data set meeting specific parameters was used. Blender v2.63a software was used to construct a 3-dimensional (3D) computational model of the spine from 2-dimensional calibrated radiographs. To accomplish this, the 3D thorax model was deformed to match the calibrated radiographs. The thorax volume was then calculated in cubic centimeters using Mimics v15 software.
  
  
  RESULTS
  The results using this computational modeling technique demonstrated that surgical correction resulted in decreased curve measurement as determined by Cobb method, and increased postoperative thoracic volume as expected. Thoracic volume significantly increased by a mean of 567 mm (P<0.001). The percent change in thoracic volume after surgical correction averaged 40% (range, 3% to 87%). The smaller the baseline volume, the greater the change in volume postoperatively (r=-0.86).Evaluation of postoperative data demonstrated that spinal curve measurement as determined by Cobb method was significantly reduced from a mean of 69 degrees (range, 50 to 96 degrees) preoperatively to 27 degrees (range, 13 to 33 degrees) postoperatively (P<0.001).
  
  
  CONCLUSIONS
  This pilot study demonstrates methodologic plausibility for measuring 3D changes in thoracic volumes using 2-dimensional imaging. This is an assessment of the novel modeling technique, to be used in larger future studies to assess clinical significance.
  
  
  METHODS
  Level 3-retrospective comparison of prospectively collected data.
authors: *Musculoskeletal Biomechanics Research Laboratory, Department of Orthopaedic Surgery †Department of Biomedical Engineering, University of Minnesota ‡Zimmer Spine, Minneapolis, MN.
authors: Jennifer K
authors: JK
authors: Wozniczka
authors: Charles G T
authors: CGT
authors: Ledonio
authors: David W
authors: DW
authors: Polly
authors: Benjamin E
authors: BE
authors: Rosenstein
authors: David J
authors: DJ
authors: Nuckley
mesh_terms: D000293:Adolescent; D002648:Child; D003198:Computer Simulation; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000503:physiopathology; D008297:Male; D010865:Pilot Projects; D011446:Prospective Studies; D011859:Radiography; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D012600:Scoliosis / Q000503:physiopathology / Q000601:surgery*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology*; D013909:Thorax / Q000473:pathology*