Original Article|Articles in Press

Associated factors and effects of coronal vertebral wedging angle in thoracic adolescent idiopathic scoliosis

Published:March 16, 2023DOI:



      Adolescent idiopathic scoliosis (AIS) causes vertebral wedging, but associated factors and the impact of vertebral wedging are still unknown. We investigated associated factors and effects of vertebral wedging in AIS using computed tomography (CT).


      Preoperative patients (n = 245) with Lenke types-1 and 2 were included. Vertebral wedging, lordosis, and rotation of the apical vertebra were measured by preoperative CT. Skeletal maturity and radiographic global alignment parameters were evaluated. Multiple regression analysis was performed on associated factors for vertebral wedging. Side-bending radiographs were evaluated using multiple regression analysis to calculate the percentage of reduction of Cobb angles to determine curve flexibility.


      The mean vertebral wedging angle was 6.8 ± 3.1°. Vertebral wedging angle was positively correlated with proximal thoracic (r = 0.40), main thoracic (r = 0.54), and thoracolumbar/lumbar curves (r = 0.38). By multiple regression, the central sacral vertical line (p = 0.039), sagittal vertical axis (p = 0.049), main thoracic curve (p = 0.008), and thoracolumbar/lumbar curve (p = 0.001) were significant factors for vertebral wedging. In traction and side-bending radiographs there were positive correlations between curve rigidity and the vertebral wedging angle (r = 0.60, r = 0.59, respectively). By multiple regression, thoracic kyphosis (p < 0.001), lumbar lordosis (p = 0.013), sacral slope (p = 0.006), vertebral wedging angle (p = 0.003), and vertebral rotation (p = 0.002) were significant factors for curve flexibility.


      Vertebral wedging angle was found to be highly correlated to coronal Cobb angle, with larger vertebral wedging indicating less flexibility.



      AIS (adolescent idiopathic scoliosis), MRI (magnetic resonance imaging), CT (computed tomography), ICCs (interclass correlation coefficients), C7-CSVL (C7 coronal plumbline from the central sacral vertical line), SVA (sagittal vertical axis), TK (thoracic kyphosis), LL (lumbar lordosis), SS (sacral slope), PI (pelvic incidence), FI (flexibility index)
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Journal of Orthopaedic Science
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Schlösser T.P.
        • van Stralen M.
        • Brink R.C.
        • Chu W.C.
        • Lam T.P.
        • Vincken K.L.
        • et al.
        Three-dimensional characterization of torsion and asymmetry of the intervertebral discs versus vertebral bodies in adolescent idiopathic scoliosis.
        Spine (Phila Pa 1976). 2014 Sep; 39: E1159-E1166
        • Parent S.
        • Labelle H.
        • Skalli W.
        • de Guise J.
        Vertebral wedging characteristic changes in scoliotic spines.
        Spine (Phila Pa 1976). 2004 Oct; 29: E455-E462
        • Mehlman C.T.
        • Araghi A.
        • Roy D.R.
        Hyphenated history: the Hueter-Volkmann law.
        Am J Orthop (Belle Mead NJ). 1997 Nov; 26: 798-800
        • Stokes I.A.
        • Spence H.
        • Aronsson D.D.
        • Kilmer N.
        Mechanical modulation of vertebral body growth. Implications for scoliosis progression.
        Spine (Phila Pa 1976). 1996 May; 21: 1162-1167
        • Modi H.N.
        • Suh S.W.
        • Song H.R.
        • Yang J.H.
        • Kim H.J.
        • Modi C.H.
        Differential wedging of vertebral body and intervertebral disc in thoracic and lumbar spine in adolescent idiopathic scoliosis - a cross sectional study in 150 patients.
        Scoliosis. 2008 Aug; 3: 11
        • Labrom F.R.
        • Izatt M.T.
        • Contractor P.
        • Grant C.A.
        • Pivonka P.
        • Askin G.N.
        • et al.
        Sequential MRI reveals vertebral body wedging significantly contributes to coronal plane deformity progression in adolescent idiopathic scoliosis during growth.
        Spine Deform. 2020 Oct; 8: 901-910
        • Cheung J.
        • Veldhuizen A.G.
        • Halberts J.P.
        • Sluiter W.J.
        • Van Horn J.R.
        Geometric and electromyographic assessments in the evaluation of curve progression in idiopathic scoliosis.
        Spine (Phila Pa 1976). 2006 Feb; 31: 322-329
        • Will R.E.
        • Stokes I.A.
        • Qiu X.
        • Walker M.R.
        • Sanders J.O.
        Cobb angle progression in adolescent scoliosis begins at the intervertebral disc.
        Spine (Phila Pa 1976). 2009 Dec; 34: 2782-2786
        • Grivas T.B.
        • Vasiliadis E.
        • Malakasis M.
        • Mouzakis V.
        • Segos D.
        Intervertebral disc biomechanics in the pathogenesis of idiopathic scoliosis.
        Stud Health Technol Inf. 2006; 123: 80-83
        • Begon M.
        • Scherrer S.A.
        • Coillard C.
        • Rivard C.H.
        • Allard P.
        Three-dimensional vertebral wedging and pelvic asymmetries in the early stages of adolescent idiopathic scoliosis.
        Spine J. 2015 Mar; 15: 477-486
        • Nault M.L.
        • Beauséjour M.
        • Roy-Beaudry M.
        • Mac-Thiong J.M.
        • de Guise J.
        • Labelle H.
        • et al.
        A predictive model of progression for adolescent idiopathic scoliosis based on 3D spine parameters at first visit.
        Spine (Phila Pa 1976). 2020 May; 45: 605-611
        • Sakashita K.
        • Kotani T.
        • Sakuma T.
        • Iijima Y.
        • Okuyama K.
        • Akazawa T.
        • et al.
        Risk factors for vertebral bridging in residual adolescent idiopathic scoliosis with thoracolumbar/lumbar curves.
        J Orthop Sci. 2022 Dec; 1 (301-303): S0949-S2658
        • Liljenqvist U.R.
        • Link T.M.
        • Halm H.F.
        Morphometric analysis of thoracic and lumbar vertebrae in idiopathic scoliosis.
        Spine (Phila Pa 1976). 2000 May; 25: 1247-1253
        • Makino T.
        • Sakai Y.
        • Kashii M.
        • Takenaka S.
        • Sugamoto K.
        • Yoshikawa H.
        • et al.
        Differences in vertebral morphology around the apical vertebrae between neuromuscular scoliosis and idiopathic scoliosis in skeletally immature patients: a three-dimensional morphometric analysis.
        BMC Muscoskel Disord. 2017 Nov; 18: 459
        • Cheung J.P.Y.
        • Cheung P.W.H.
        • Yeng W.C.
        • Chan L.C.K.
        Does curve regression occur during underarm bracing in patients with adolescent idiopathic scoliosis?.
        Clin Orthop Relat Res. 2020 Feb; 478: 334-345
        • Lenke L.G.
        • Betz R.R.
        • Harms J.
        • Bridwell K.H.
        • Clements D.H.
        • Lowe T.G.
        • et al.
        Adolescent idiopathic scoliosis: a new classification to determine extent of spinal arthrodesis.
        J Bone Joint Surg Am. 2001 Aug; 83: 1169-1181
        • Cheh G.
        • Lenke L.G.
        • Lehman Jr., R.A.
        • Kim Y.J.
        • Nunley R.
        • Bridwell K.H.
        The reliability of preoperative supine radiographs to predict the amount of curve flexibility in adolescent idiopathic scoliosis.
        Spine (Phila Pa 1976). 2007 Nov; 32: 2668-2672
        • Ramchandran S.
        • Monsour A.
        • Mihas A.
        • George K.
        • Errico T.
        • George S.
        Impact of supine radiographs to assess curve flexibility in the treatment of adolescent idiopathic scoliosis.
        Global Spine J. 2021 Oct; 12: 1731-1735
        • Kanda Y.
        Investigation of the freely available easy-to-use software 'EZR' for medical statistics.
        Bone Marrow Transplant. 2013 Mar; 48: 452-458
        • Vergari C.
        • Karam M.
        • Pietton R.
        • Vialle R.
        • Ghanem I.
        • Skalli W.
        • et al.
        Spine slenderness and wedging in adolescent idiopathic scoliosis and in asymptomatic population: an observational retrospective study.
        Eur Spine J. 2020 Apr; 29: 726-736
        • Keenan B.E.
        • Izatt M.T.
        • Askin G.N.
        • Labrom R.D.
        • Bennett D.D.
        • Pearcy M.J.
        • et al.
        Sequential magnetic resonance imaging reveals individual level deformities of vertebrae and discs in the growing scoliotic spine.
        Spine Deform. 2017 May; 5: 197-207
        • Perdriolle R.
        • Becchetti S.
        • Vidal J.
        • Lopez P.
        Mechanical process and growth cartilages. Essential factors in the progression of scoliosis.
        Spine (Phila Pa 1976). 1993 Mar; 18: 343-349
        • Mohanty S.P.
        • Pai Kanhangad M.
        • Gullia A.
        Curve severity and apical vertebral rotation and their association with curve flexibility in adolescent idiopathic scoliosis.
        Musculoskelet Surg. 2021 Cec; 105: 303-308
        • Ameri E.
        • Behtash H.
        • Mobini B.
        • Daraie A.
        Predictors of curve flexibility in adolescent idiopathic scoliosis: a retrospective study of 100 patients.
        Acta Med Iran. 2015; 53: 182-185
        • Baroncini A.
        • Trobisch P.D.
        • Berjano P.
        • Lamartina C.
        • Kobbe P.
        • Tingart M.
        • et al.
        Correlation between age, coronal and sagittal parameters and spine flexibility in patients with adolescent idiopathic scoliosis.
        Spine Deform. 2021 Nov; 9: 1525-1531
        • Ohrt-Nissen S.
        • Shigematsu H.
        • Cheung J.P.Y.
        • Luk K.D.K.
        • Samartzis D.
        Predictability of coronal curve flexibility in postoperative curve correction in adolescent idiopathic scoliosis: the effect of the sagittal profile.
        Global Spine J. 2020 May; 10: 303-311