title: Cervical vertebrae maturation method morphologic criteria: poor reproducibility.
abstract: BACKGROUND
  The cervical vertebrae maturation (CVM) method has been advocated as a predictor of peak mandibular growth. A careful review of the literature showed potential methodologic errors that might influence the high reported reproducibility of the CVM method, and we recently established that the reproducibility of the CVM method was poor when these potential errors were eliminated. The purpose of this study was to further investigate the reproducibility of the individual vertebral patterns. In other words, the purpose was to determine which of the individual CVM vertebral patterns could be classified reliably and which could not.
  
  
  METHODS
  Ten practicing orthodontists, trained in the CVM method, evaluated the morphology of cervical vertebrae C2 through C4 from 30 cephalometric radiographs using questions based on the CVM method. The Fleiss kappa statistic was used to assess interobserver agreement when evaluating each cervical vertebrae morphology question for each subject. The Kendall coefficient of concordance was used to assess the level of interobserver agreement when determining a "derived CVM stage" for each subject.
  
  
  RESULTS
  Interobserver agreement was high for assessment of the lower borders of C2, C3, and C4 that were either flat or curved in the CVM method, but interobserver agreement was low for assessment of the vertebral bodies of C3 and C4 when they were either trapezoidal, rectangular horizontal, square, or rectangular vertical; this led to the overall poor reproducibility of the CVM method. These findings were reflected in the Fleiss kappa statistic. Furthermore, nearly 30% of the time, individual morphologic criteria could not be combined to generate a final CVM stage because of incompatible responses to the 5 questions. Intraobserver agreement in this study was only 62%, on average, when the inconclusive stagings were excluded as disagreements. Intraobserver agreement was worse (44%) when the inconclusive stagings were included as disagreements. For the group of subjects that could be assigned a CVM stage, the level of interobserver agreement as measured by the Kendall coefficient of concordance was only 0.45, indicating moderate agreement.
  
  
  CONCLUSIONS
  The weakness of the CVM method results, in part, from difficulty in classifying the vertebral bodies of C3 and C4 as trapezoidal, rectangular horizontal, square, or rectangular vertical. This led to the overall poor reproducibility of the CVM method and our inability to support its use as a strict clinical guideline for the timing of orthodontic treatment.
authors.affiliation: Department of Orthodontics, University of Iowa, Iowa City, USA.
authors.forename: Trenton S
authors.initials: TS
authors.lastname: Nestman
authors.forename: Steven D
authors.initials: SD
authors.lastname: Marshall
authors.forename: Fang
authors.initials: F
authors.lastname: Qian
authors.forename: Nathan
authors.initials: N
authors.lastname: Holton
authors.forename: Robert G
authors.initials: RG
authors.lastname: Franciscus
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Southard
mesh_terms: D000293:Adolescent; D000365:Age Determination by Skeleton / Q000379:methods*; D001846:Bone Development; D002508:Cephalometry; D002574:Cervical Vertebrae / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000254:growth & development*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D015203:Reproducibility of Results