Validation of a Quantitative Cervical Vertebral Bone Age Model in North Indian Children and Adolescents: A Cross-Sectional Study.

INTRODUCTION: The assessment of skeletal maturity is essential for orthodontic treatment planning and evaluation in growing patients. The present study aimed to validate the accuracy and reliability of quantitative cervical vertebral bone age (CVBA) regression formulae in a North Indian population, using the Fishman hand-wrist method as the reference standard. MATERIALS AND METHODS: This retrospective cross-sectional study included 180 North Indian children (90 males and 90 females) aged 4-18 years with pre-treatment digital lateral cephalometric and left-hand-wrist radiographs taken on the same day. Eleven geometric measurements of the C2-C4 vertebrae were performed using the Dolphin Imaging software. Previously published sex-specific regression equations were applied to derive continuous CVBA values. Hand-wrist skeletal age was determined and coded from hand-wrist radiographs independently by two blinded, calibrated orthodontists using the Fishman method and converted to decimal years. Chronological age was calculated from birth records. The reliability of the measurements, correlation, agreement (Bland-Altman), and differences among the three age estimates were statistically analyzed. RESULTS: Mean chronological age was 11.95 ± 1.78 years, formula-derived CVBA 12.03 ± 1.74 years, and Fishman hand-wrist skeletal age 12.02 ± 1.77 years (repeated-measures ANOVA, p = 0.882). Pearson correlation coefficients exceeded 0.915 (mostly > 0.988) for all pairwise comparisons. Bland-Altman analysis revealed negligible bias (+0.01 years) between CVBA and Fishman skeletal age, with 95% limits of agreement of -0.48 to +0.50 years. Intra- and inter-examiner ICCs for vertebral measurements were >0.94 and >0.92, respectively, for CVBA and hand-wrist skeletal age. No significant differences were found across sex or age subgroups. CONCLUSIONS: The quantitative CVBA model exhibited outstanding accuracy, reliability, and interchangeability with the Fishman hand-wrist method in North Indian children and adolescents. Utilizing routinely acquired lateral cephalograms provides a reproducible, objective, and radiation-efficient alternative for assessing skeletal maturity, thereby justifying their routine clinical implementation in this population.