title: Experimental validation of a patient-specific model of orthotic action in adolescent idiopathic scoliosis.
abstract: Personalized modeling of brace action has potential in improving brace efficacy in adolescent idiopathic scoliosis (AIS). Model validation and simulation uncertainty are rarely addressed, limiting the clinical implementation of personalized models. We hypothesized that a thorough validation of a personalized finite element model (FEM) of brace action would highlight potential means of improving the model.
  
  
  
  Forty-two AIS patients were included retrospectively and prospectively. Personalized FEMs of pelvis, spine and ribcage were built from stereoradiographies. Brace action was simulated through soft cylindrical pads acting on the ribcage and through displacements applied to key vertebrae. Simulation root mean squared errors (RMSEs) were calculated by comparison with the actual brace action (quantified through clinical indices, vertebral positions and orientations) observed in in-brace stereoradiographies.
  
  
  
  Simulation RMSEs of Cobb angle and vertebral apical axial rotation was lower than measurement uncertainty in 79 % of the patients. Pooling all patients and clinical indices, 87 % of the indices had lower RMSEs than the measurement uncertainty.
  
  
  
  In-depth analysis suggests that personalization of spinal functional units mechanical properties could improve the simulation's accuracy, but the model gave good results, thus justifying further research on its clinical application.
authors.affiliation: Arts et Metiers ParisTech, LBM/Institut de Biomecanique Humaine Georges Charpak, 151 bd de l'Hopital, 75013, Paris, France. c.vergari@gmail.com.
authors.forename: Claudio
authors.identifier: 0000-0002-7049-2405
authors.initials: C
authors.lastname: Vergari
authors.affiliation: Unite Rachis, CHU-Hopital Bellevue, 25 Boulevard Pasteur, 42100, Saint-Etienne, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Courtois
authors.affiliation: Unite Rachis, CHU-Hopital Bellevue, 25 Boulevard Pasteur, 42100, Saint-Etienne, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Ebermeyer
authors.affiliation: Department of Paediatric Orthopaedics, Armand Trousseau Hospital, Université Pierre et Marie Curie-Paris 6, 75571, Paris, France.
authors.forename: Houssam
authors.initials: H
authors.lastname: Bouloussa
authors.affiliation: Department of Paediatric Orthopaedics, Armand Trousseau Hospital, Université Pierre et Marie Curie-Paris 6, 75571, Paris, France.
authors.forename: Raphaël
authors.initials: R
authors.lastname: Vialle
authors.affiliation: Arts et Metiers ParisTech, LBM/Institut de Biomecanique Humaine Georges Charpak, 151 bd de l'Hopital, 75013, Paris, France.
authors.forename: Wafa
authors.initials: W
authors.lastname: Skalli
mesh_terms: D000293:Adolescent; D001915:Braces; D003198:Computer Simulation; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D010388:Pelvis / Q000000981:diagnostic imaging / Q000503:physiopathology; D011446:Prospective Studies; D012189:Retrospective Studies; D012272:Ribs / Q000000981:diagnostic imaging / Q000503:physiopathology; D012399:Rotation; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy; D013131:Spine / Q000000981:diagnostic imaging / Q000503:physiopathology
keywords: Brace; Finite element model; Pediatrics; Spine deformity