title: Scoliosis surgery in patients with adolescent idiopathic scoliosis does not alter lung volume: a 3-dimensional computed tomography-based study.
abstract: METHODS
  Retrospective study of surgically treated patients with adolescent idiopathic scoliosis.
  
  
  OBJECTIVE
  To determine the change in lung volume after the surgical correction of scoliosis using a volumetric reconstruction of lung volume from computed tomographic (CT) scans.
  
  
  BACKGROUND
  Previously published studies have shown that pulmonary function tests improve after scoliosis correction; however, these results are not consistent. CT-based volumetric studies in patients with scoliosis have previously shown differences in lung volume and lung volume ratio when compared with a normal population. To date, no study exists that analyzes changes in these parameters after scoliosis surgery.
  
  
  METHODS
  A total of 29 patients with adolescent idiopathic scoliosis who had pre- and postoperative CT scans on file were included in this study. Three-dimensional lung volume reconstruction was performed (TeraRecon software, TeraRecon, Inc., Foster City, CA). Appropriate masking methods were used to isolate the lung tissue. Total lung volumes, left and right lung volumes, and left/right lung volume ratio were obtained from the pre- and postoperative CT scans. Hemithoracic symmetry, pre- and postoperative Cobb angle, and kyphosis were also calculated.
  
  
  RESULTS
  Neither total lung volume nor left/right lung volume ratio changed significantly postoperatively. Surgery did not significantly change total lung volume (P = 0.87), right lung volume (P = 0.69), left lung volume (P = 0.70), or the ratio between right and left lung volumes (P = 0.87). Hemithoracic asymmetry was significantly improved (P < 0.001). Median preoperative major Cobb angle was 53.2° and median preoperative kyphosis was 32.8°. Postoperatively, the median major Cobb angle was 15.0°, resulting in a 70% Cobb correction, and mean postoperative kyphosis was 31.1°.
  
  
  CONCLUSIONS
  Corrective scoliosis surgery does not alter total lung volume or the ratio of right-to-left lung volume. Deformity correction leads to an improvement in the symmetry of the thoracic architecture and costovertebral joint mechanics, as evidenced by the improved hemithoracic asymmetry. Thus, the change in pulmonary function tests, which has been previously documented, may be a dynamic rather than a static phenomenon.
  
  
  METHODS
  4.
authors.affiliation: *Departments of Orthopaedic Surgery; and †Radiology, Montefiore Medical Center, The Albert Einstein College of Medicine, Bronx, New York, NY.
authors.forename: Vishal
authors.initials: V
authors.lastname: Sarwahi
authors.forename: Etan P
authors.initials: EP
authors.lastname: Sugarman
authors.forename: Adam L
authors.initials: AL
authors.lastname: Wollowick
authors.forename: Terry D
authors.initials: TD
authors.lastname: Amaral
authors.forename: Elliot D
authors.initials: ED
authors.lastname: Harmon
authors.forename: Beverly
authors.initials: B
authors.lastname: Thornhill
mesh_terms: D000293:Adolescent; D002648:Child; D006801:Humans; D021621:Imaging, Three-Dimensional; D008168:Lung / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008176:Lung Volume Measurements / Q000379:methods*; D008297:Male; D019637:Orthopedic Procedures; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D020127:Recovery of Function; D012189:Retrospective Studies; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome