Validating the Supraorbital Notch-Nasion-Supraorbital Notch Angle as a Marker for Metopic Craniosynostosis Severity

Abstract

Objective: Metopic craniosynostosis (MCS) can be difficult to differentiate from metopic ridge (MR) or normal frontal morphology. This study assess whether the supraorbital notch-nasion-supraorbital notch (SNS) angle can help identify MCS. Methods: Records of 212 patients with preoperative three-dimensional computed tomography scans were examined. The SNS angles, surgeon craniofacial dysmorphology rankings, and CranioRate metopic severity scores (MSSs) were compared with the Spearman rank correlation coefficient. Receiver operating characteristic (ROC) curves with Youden J-statistic and cross-validation of regression models assessed the ability of these measures to predict surgery. Results: A total of 212 patients were included, consisting of 78 MCS, 37 MR, and 97 controls. Both the mean SNS angle (MCS: 111.7 ± 10.7 degrees, MR: 126.0 ± 8.2 degrees, controls: 130.7 ± 8.8 degrees P < 0.001) and MSS (MCS: 5.9 ± 2.0, MR: 1.4 ± 1.9, controls: 0.2 ± 1.9, P < 0.001) were different among the cohorts. The mean SNS angle (111.5 ± 10.7 versus 129.1 ± 8.8, P < 0.001) was lower in those who had surgery and CranioRate score (5.9 ± 2.1 versus 0.8 ± 2.2, P < 0.001) was higher in those who underwent surgery. SNS angles were positively correlated with surgeon craniofacial dysmorphology rankings (r = 0.41, P < 0.05) and CranioRate MSS (r = 0.54, P < 0.05). The ROC curve requiring high sensitivity revealed an SNS angle of 124.8 degrees predicted surgery with a sensitivity of 88.7% and a specificity of 71.3%. A ROC curve using the CranioRate MCC values ≥3.19 predicted surgery with 88.7% sensitivity and 94.7% specificity. Conclusion: Orbital dysmorphology in patients with MCS is well captured by the supraorbital-nasion angle. Both the SNS angle and CranioRate MSS scores accurately predict surgical intervention.