Spheno-occipital synchondrosis as a reliable indicator of skeletal maturity: A systematic review and meta-analysis.

The present review systematically analyzed the available literature on the application of spheno-occipital synchondrosis (SOS) as a skeletal maturity indicator in growing subjects reporting for orthodontic treatment. A systematic search of the available literature on SOS for assessment of skeletal maturity was performed in various databases like Google Scholar, PubMed, and Scopus until December 2023. The risk of bias assessment was performed using the STARD (Standards for the Reporting of Diagnostic Accuracy Studies) statement. A narrative summary on the correlation of SOS with cervical vertebral maturation index (CVMI), hand-wrist maturation (HWM), and chronologic age was done, followed by a meta-analysis with a fixed effects model to quantitatively assess the correlation of SOS with CVMI. A total of eight studies were included in the review, and seven of them reported a significant, strong positive correlation between SOS and CVMI, two studies reported a moderate correlation of SOS with HWM stages, and seven studies reported a good to moderate correlation between SOS and chronologic age. Most included studies had a low risk of bias and were considered good-quality studies. On performing the meta-analysis of both the 4- and 5-stage SOS, a significant positive correlation of SOS with CVMI was noted (P<0.05). The present high-quality evidence suggests a strong positive correlation between SOS and CVMI, a moderate correlation between SOS and HMW, and a moderate correlation between SOS and chronologic age. Hence, SOS can reliably be used as a skeletal maturity indicator.