Discriminatory ability of the skeletal maturation index and the cervical vertebrae maturation index in detecting peak pubertal growth in Indonesian and white subjects with receiver operating characteristics analysis

Abstract

In this study, we aimed to determine the effectiveness of the skeletal maturation index (SMI) and the cervical vertebrae maturation (CVM) index in discriminating between patients who have yet to attain their peak pubertal growth, compared with those who have reached or passed it. An additional aim was to determine whether there was any significant difference in the ability of the 2 methods to predict peak pubertal growth. The study included 2167 patients with hand-wrist and lateral cephalometric radiographs. There were 648 Indonesian boys and 303 white boys (age range, 10-17 years), and 774 Indonesian girls and 442 white girls (age range, 8-15 years). The SMI was used to evaluate the stages of skeletal maturity from hand-wrist radiographs, and the CVM index was used to evaluate skeletal maturity from lateral cephalograms. Several commonly used cephalometric parameters representing maxillary and mandibular dimensions were also measured to construct growth curves and calculate peak velocity. Receiver operating characteristic (ROC) analysis was performed for the craniofacial morphology parameters for both sex and ethnic groups. The percentages of correctly classified subjects into the appropriate maturational stages for the mandibular parameters, as well as the stages with high sensitivity values for the maxillary parameters, showed that both the CVM index and the SMI have good discriminatory ability. On average, the results of the area under curve (AUC) for the SMI (AUC >0.9) were greater than for the CVM (AUC >0.8), and the differences between them were also statistically significant (P <0.05 for all parameters investigated). However, the curves for both CVM and SMI approached the top left corner of the ROC graph, suggesting that both tests have good discriminatory ability, and the differences between the methods were only between 1% and 7%. Both the CVM index and the SMI are valid methods to discriminate between patients who have not yet attained peak pubertal growth and those who have reached or passed it. The differences in discriminatory ability between the SMI and the CVM index in detecting peak pubertal growth were small. These results question the necessity of taking hand-wrist radiographs and exposing a child to additional radiation when the discriminatory ability is similar with the CVM index, which is readily derived from most lateral cephalograms.