title: Patient-specific spinal stiffness in AIS: a preoperative and noninvasive method.
abstract: BACKGROUND
  The clinical tests currently used to assess spinal biomechanics preoperatively are unable to assess true mechanical spinal stiffness. They rely on spinal displacement without considering the force required to deform a patient's spine. We propose a preoperative method for noninvasively quantifying the three-dimensional patient-specific stiffness of the spines of adolescent idiopathic scoliosis patients.
  
  
  METHODS
  The technique combines a novel clinical test with numerical optimization of a finite element model of the patient's spine.
  
  
  RESULTS
  A pilot study conducted on five patients showed that the model was able to provide accurate 3D reconstruction of the spine's midline and predict the spine's stiffness for each patient in flexion, bending, and rotation. Statistically significant variation of spinal stiffness was observed between the patients.
  
  
  CONCLUSIONS
  This result confirms that spinal biomechanics is patient-specific, which should be taken into consideration to individualize surgical treatment.
authors.affiliation: Institute for Surgical Technology and Biomechanics, University of Bern, Stauffacherstrasse 78, 3014, Bern, Switzerland, steve.berger@istb.unibe.ch.
authors.forename: Steve
authors.initials: S
authors.lastname: Berger
authors.forename: Marcelo
authors.initials: M
authors.lastname: de Oliveira
authors.forename: Oliveira
authors.initials: O
authors.lastname: Marcello
authors.forename: Steffen
authors.initials: S
authors.lastname: Schuman
authors.forename: Jacques
authors.initials: J
authors.lastname: Schneider
authors.forename: Daniel
authors.initials: D
authors.lastname: Studer
authors.forename: Carol
authors.initials: C
authors.lastname: Hasler
authors.forename: Guoyan
authors.initials: G
authors.lastname: Zheng
authors.forename: Philippe
authors.initials: P
authors.lastname: Büchler
mesh_terms: D000293:Adolescent; D001696:Biomechanical Phenomena; D020342:Finite Element Analysis; D006801:Humans; D008297:Male; D010865:Pilot Projects; D016059:Range of Motion, Articular; D012399:Rotation; D012600:Scoliosis / Q000503:physiopathology* / Q000601:surgery; D013131:Spine / Q000503:physiopathology*