Effects of trunk position on back surface-contour measured by raster stereophotography.
A study of the contour of the surface of the back was conducted using the Quantec spinal image system (QSIS; raster stereophotography) and the Vicon 3-dimensional (3-D) motion analysis system with a plaster model of the scoliotic spine. With postural changes in 3 dimensions came alterations in the surface shape of the back. Most changes in QSIS parameters occurred in the coronal plane. The study showed that model 1, with 9 degrees of Q angle (similar to Cobb angle in the coronal plane) in right thoracolumbar scoliosis, altered 3-D metrics less than model 2 did, with 54 degrees of Q angle in scoliosis. The change in the position of the trunk in the transverse plane had a more significant impact on the QSIS parameters. Raster stereophotography has been used clinically to monitor curve progression. Changes in transverse rotation of the trunk correlate significantly with variations in Q angle and axial rotation. Clinicians using a raster stereophotograph system to assess scoliotic deformity need to control postural sway, as doing so results in more stable and reproducible measurements that can be used for clinical follow-up.
Department of Orthopaedic Surgery, Medical College of Wisconsin, Children's Hospital of Wisconsin, Milwaukee, USA.
Xue C
XC
Liu
John G
JG
Thometz
Roger M
RM
Lyon
Linda
L
McGrady
D001415:Back / Q000473:pathology*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008953:Models, Anatomic; D015903:Moire Topography; D010780:Photogrammetry / Q000379:methods*; D011187:Posture; D012399:Rotation; D012600:Scoliosis / Q000473:pathology*