title: Evaluation of a Patient-Specific Finite-Element Model to Simulate Conservative Treatment in Adolescent Idiopathic Scoliosis.
abstract: METHODS
  Retrospective validation study.
  
  
  OBJECTIVE
  To propose a method to evaluate, from a clinical standpoint, the ability of a finite-element model (FEM) of the trunk to simulate orthotic correction of spinal deformity and to apply it to validate a previously described FEM.
  
  
  BACKGROUND
  Several FEMs of the scoliotic spine have been described in the literature. These models can prove useful in understanding the mechanisms of scoliosis progression and in optimizing its treatment, but their validation has often been lacking or incomplete.
  
  
  METHODS
  Three-dimensional (3D) geometries of 10 patients before and during conservative treatment were reconstructed from biplanar radiographs. The effect of bracing was simulated by modeling displacements induced by the brace pads. Simulated clinical indices (Cobb angle, T1-T12 and T4-T12 kyphosis, L1-L5 lordosis, apical vertebral rotation, torsion, rib hump) and vertebral orientations and positions were compared to those measured in the patients' 3D geometries.
  
  
  RESULTS
  Errors in clinical indices were of the same order of magnitude as the uncertainties due to 3D reconstruction; for instance, Cobb angle was simulated with a root mean square error of 5.7°, and rib hump error was 5.6°. Vertebral orientation was simulated with a root mean square error of 4.8° and vertebral position with an error of 2.5 mm.
  
  
  CONCLUSIONS
  The methodology proposed here allowed in-depth evaluation of subject-specific simulations, confirming that FEMs of the trunk have the potential to accurately simulate brace action. These promising results provide a basis for ongoing 3D model development, toward the design of more efficient orthoses.
authors.affiliation: Arts et Metiers ParisTech, LBM, 151 bd de l'Hopital, 75013 Paris, France. Electronic address: c.vergari@gmail.com.
authors.forename: Claudio
authors.initials: C
authors.lastname: Vergari
authors.affiliation: Arts et Metiers ParisTech, LBM, 151 bd de l'Hopital, 75013 Paris, France.
authors.forename: Gwenael
authors.initials: G
authors.lastname: Ribes
authors.affiliation: Arts et Metiers ParisTech, LBM, 151 bd de l'Hopital, 75013 Paris, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Aubert
authors.affiliation: Arts et Metiers ParisTech, LBM, 151 bd de l'Hopital, 75013 Paris, France.
authors.forename: Clayton
authors.initials: C
authors.lastname: Adam
authors.affiliation: Department of Pediatric Orthopedics, Necker Enfants Malades Hospital, AP-HP, 149 rue de Sevres, 75743 Paris Cedex 15, France.
authors.forename: Lotfi
authors.initials: L
authors.lastname: Miladi
authors.affiliation: Pediatric Orthopaedics Department, Robert Debré Hospital, AP-HP, Paris Diderot University, 48 Bd Sérurier, 75019 Paris, France.
authors.forename: Brice
authors.initials: B
authors.lastname: Ilharreborde
authors.affiliation: Department of Pediatric Orthopedics, Hospices Civils de Lyon, Claude Bernard Lyon 1 University, Lyon, France.
authors.forename: Kariman
authors.initials: K
authors.lastname: Abelin-Genevois
authors.affiliation: Arts et Metiers ParisTech, LBM, 151 bd de l'Hopital, 75013 Paris, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Rouch
authors.affiliation: Arts et Metiers ParisTech, LBM, 151 bd de l'Hopital, 75013 Paris, France.
authors.forename: Wafa
authors.initials: W
authors.lastname: Skalli
keywords: 3D reconstruction; Adolescent idiopathic scoliosis; Biplanar radiography; Brace; Simulation