The Relationship between 3-dimensional Spinal Alignment, Thoracic Volume, and Pulmonary Function in Surgical Correction of Adolescent Idiopathic Scoliosis: A 5-year Follow-up Study

Aaron J. Buckland, Dainn Woo, Dennis Vasquez-Montes, Michelle Marks, Amit Jain, Amer Samdani, Randal R. Betz, Thomas J. Errico, Baron Lonner, Peter O. Newton

Research output: Contribution to journalReview articlepeer-review

1 Scopus citations


Study Design.Retrospective review of a prospective multicenter database.Objective.The aim of this study was to study the effects of thoracic kyphosis (TK) restoration in adolescent idiopathic scoliosis (AIS) Type 1 and 2 curves on postoperative thoracic volume (TV) and pulmonary function.Summary of Background Data.Surgical correction of AIS is advocated to preserve or improve pulmonary function, prevent progressive deformity and pain, and improve self-appearance. Restoration of sagittal and 3D alignment, particularly TK, has become increasingly emphasized in efforts to improve pulmonary function, TVs, sagittal balance, and prevent adjacent-segment degeneration and deformity.Methods.AIS patients 10 to 21years undergoing surgical correction of Lenke Type 1 and 2 curves with baseline, 1st-erect-postoperative, and 5-year (5Y) postoperative visits including stereoradiographic assessment and pulmonary function tests (PFTs) were included. 3D-radiographic analysis was performed to assess spinal-alignment, chest-wall, and rib-cage dimensions at each time point. Outcome variables were analyzed between time points with one-way analysis of variance and between variables with linear regression analysis.Results.Thirty-nine patients (37 females, 14.4 ± 2.2 years) were included. 3D-spinal-alignment analyses demonstrated significant reduction in preoperative to first-erect thoracic and lumbar Cobb-angles, an increase in TK:T2-12 (19.67°-39.69°) and TK:T5-12 (9.47°-28.05°), and reduction in apical vertebral rotation (AVR) (P < 0.001 for all). Spinal-alignment remained stable from 1st-erect to 5Y. 3D rib-cage analysis demonstrated small reductions in baseline to first-erect depth (145-139 mm), width (235-232 mm), and increase in height (219-230 mm, P < 0.01), but no significant change in volume (5161-5222 cm,3P = 0.184). From 1st-erect to 5Y, significant increases in depth, width, height, and volume (all P < 0.001) occurred. PFTs showed preoperative to 5Y improvement in first second of Forced Expiratory Volume (FEV1) (2.74-2.98 L, P = 0.005) and forced vital capacity (FVC) (3.23-3.47 L, P = 0.008); however, total lung capacity (TLC) did not change (P = 0.517). Percent-predicted TLC decreased (Pre: 101.3% to 5Y: 89.3%, P < 0.001); however, percent-predicted forced expiratory volume and FVC did not (P = 0.112 and P = 0.068).Conclusion.Although TK increases, coronal-Cobb and AVR decrease postoperatively; these do not directly influence TV, which increases from 1st-erect to 5Y due to growth, corresponding with increases in FEV1 and FVC at 5Y; however, surgical restoration of kyphosis does not directly improve pulmonary function.Level of Evidence: 3.

Original languageEnglish (US)
Pages (from-to)983-992
Number of pages10
Issue number14
StatePublished - Jul 15 2020


  • adolescent idiopathic scoliosis
  • alignment
  • operative
  • outcomes
  • pulmonary function
  • rib-cage
  • sagittal balance
  • thoracic kyphosis
  • three-dimensional analysis

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Clinical Neurology


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