Recently, I read the article entitled “Evaluating the agreement of skeletal age assessment based on hand-wrist and cervical vertebrae radiography” in the December issue (Beit P, Peltomäki T, Schätzle M, Signorelli L, Patcas R. Am J Orthod Dentofacial Orthop 2013;144:838-47). This study uses elegant statistical models to conclude that “morphometric assessment of age-dependent changes in the cervical spine offers no advantage over chronologic age, in either assessing skeletal age or predicting the pubertal growth spurt.” However, given the recording method used, I wonder whether these results could truly be generalized to all the “classic” cervical vertebral maturation (CVM) methods. Since this aspect was not clearly mentioned in the article, I would like to ask the authors to explain better the rationale of using those procedures in the light of these considerations. (1) Concavity was assessed as the ratio of the true concavity with the lower width of the vertebral body. Although this procedure would not be consistent with the CVM methods, a given ratio of concavity/width might be compatible with both a deep concavity in a large body (more mature) and a little concavity in a narrow body (less mature). (2) The classical CVM methods assess body shape of the third and fourth cervical vertebral bodies as a whole and, for subsequent staging, take into account the shape of both bodies together. On the contrary, in the Beit at al article, 2 different shape parameters were used individually: (a) the ratio of the anterior height to the lower width (called “anterior height”), and (b) the angle between the upper and lower borders (called “angle”). An important biologic concept is that once a vertebral body reaches the rectangular horizontal shape (with parallel upper and lower borders), this angle would not change, even as skeletal age increases (with increasing skeletal age, the whole shape would continue to change into square and then rectangular vertical). This is why this last parameter was the least correlated with skeletal age.
Perhaps the authors missed a simple step in this otherwise well-done study. Why not use a comprehensive cephalometric analysis to derive reliable CVM stages exactly according to the described methods, and then use these stages in the diagnostic performance analysis? Importantly, if cephalometrics can be used to assess reliably morphologic changes, it can also be used in any clinical setting for classical staging.
In my opinion, the authors provided robust results that, however, should apply strictly to the used recording method of cervical maturation, and any generalization to the classical CVM methods should be done with caution.