title: A new technique for the three-dimensional study of the spine in vitro and in vivo by using a motion-analysis system.
abstract: We introduce a new method with a motion-analysis system (MAS) to study the vertebral model in vitro. Compared with the currently most accurate technique, roentgen stereophotogrammetric analysis (RSA), the difference between the RSA and the MAS is 0.12 degree +/- 1.64 degrees. An accuracy with an error of 0.08 degree +/- 1.15 degrees is determined by means of an angle gauge. Although a significant difference between the MAS and the goniometer (p = 0.04) is found around the X-axis (theta; transverse plane), it is limited to < 1 degree. The MAS provides an in-depth insight into the mechanism of the three-dimensional rotation at each vertebra in vivo. The backward inclination of the apical vertebra (AV) and forward inclination of the upper-end vertebra (UEV) around the Y-axis (phi) results in a correction of the hypokyphosis shown by the Cobb angle in the sagittal plane. The clockwise rotation of the UEV in the Z-axis (psi) leads to a reduction of the Cobb angle in the frontal plane. Additionally, the MAS as an intraoperative alternative shows different results of the derotation maneuver by the Cotrel-Dubousset instrumentation (CDI) compared with the computed tomography (CT) scan. Our method gives more direct details of the derotation not influenced by patient posture, as observed in the CT scan.
authors.affiliation: Department of Orthopaedic Surgery, University Hospital Pellenberg, Katholieke Universiteit Leuven, Belgium.
authors.forename: X C
authors.initials: XC
authors.lastname: Liu
authors.forename: G
authors.initials: G
authors.lastname: Fabry
authors.forename: L
authors.initials: L
authors.lastname: Labey
authors.forename: L
authors.initials: L
authors.lastname: Van den Berghe
authors.forename: R
authors.initials: R
authors.lastname: Van Audekercke
authors.forename: G
authors.initials: G
authors.lastname: Molenaers
authors.forename: P
authors.initials: P
authors.lastname: Moens
mesh_terms: D000293:Adolescent; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007432:Intraoperative Period; D009038:Motion; D009983:Orthopedic Equipment; D009985:Orthopedics / Q000379:methods*; D011184:Postoperative Period; D012399:Rotation; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D013131:Spine / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D014057:Tomography, X-Ray Computed