The Rib Vertebra Angle Difference and its measurement in 3D for the evaluation of early onset scoliosis

G. Foley, C. E. Aubin, H. Labelle, J. Sanders, J. D'Astous, C. Johnston, S. Parent

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Scopus citations

Abstract

The Rib Vertebra Angle Difference (RVAD) as defined by Mehta (1972) is used to predict the progression of early onset scoliosis. No clear physical significance has been established for this measurement. The purpose of this study was to evaluate the RVAD along the thoracic spine and the equivalent measurement on 3D reconstructions of the spine and rib cage of early onset scoliosis patients in order to determine their relationship with the geometry of the chest wall and evolution along the spine. The RVAD was measured on PA radiographs of 42 infantile scoliotic patients (Cobb >20°) from T4 to T10 according to the method described by Mehta. The RVAD 3D was computed using the same landmarks from the 3D reconstruction generated from the calibrated biplanar radiographs. Cases were divided into Phase I and Phase II using Mehta's classification based on the rib head overlap with the apical vertebral body on coronal plane radiographs. A linear relationship exists between the Metha (2D) and 3D RVAD for both Phase I (r = 0.87) and Phase II (r = 0.78) patients. For more severe deformities (RVAD 3D ≥ 35°), a relationship was found between RVAD 3D and the axial rotation of the thoracic vertebrae (r = 0.51) in Phase II patients. However, no significant relationship exists between axial rotation and RVAD 3D for Phase I patients as well as Mehta's RVAD. Maximal RVAD measurements were located 2 1/2 levels above the apical vertebra. Results indicated that RVAD 3D provides additional information to Mehta's RVAD on the torsional nature of the deformity. Considering the importance of clinical indices to assess the progression of early onset scoliosis, this study raises some questions on looking solely at the RVAD measured on radiographs at the apical vertebra of Phase I patients and suggests considering also levels above the apex of the scoliotic curve and 3D measurements. Further investigation is required to fully understand the 3D nature of the spine and rib cage deformities.

Original languageEnglish (US)
Title of host publicationResearch into Spinal Deformities 8
PublisherIOS Press
Pages238-241
Number of pages4
ISBN (Print)9781614990666
DOIs
StatePublished - Jan 1 2012
Event9th Biennial Meeting of the International Research Society of Spinal Deformities, IRSSD 2012 - Poznan, Poland
Duration: Jul 1 2012Jul 4 2012

Publication series

NameStudies in Health Technology and Informatics
Volume176
ISSN (Print)0926-9630
ISSN (Electronic)1879-8365

Other

Other9th Biennial Meeting of the International Research Society of Spinal Deformities, IRSSD 2012
CountryPoland
CityPoznan
Period7/1/127/4/12

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Keywords

  • Axial rotation
  • Early onset scoliosis
  • Rib vertebra angle difference
  • Rib vertebra angle difference 3D

ASJC Scopus subject areas

  • Biomedical Engineering
  • Health Informatics
  • Health Information Management

Cite this

Foley, G., Aubin, C. E., Labelle, H., Sanders, J., D'Astous, J., Johnston, C., & Parent, S. (2012). The Rib Vertebra Angle Difference and its measurement in 3D for the evaluation of early onset scoliosis. In Research into Spinal Deformities 8 (pp. 238-241). (Studies in Health Technology and Informatics; Vol. 176). IOS Press. https://doi.org/10.3233/978-1-61499-067-3-238