Sphenotemporal and Fronto-Orbital Dysmorphology in Unilateral Coronal Synostosis Using Geometric Morphometric Curve-Based Analysis.

Background: Geometric morphometric analysis with Procrustes superimposition is a commonly used method to characterize and study complex dysmorphology. The present study employs an advanced Procrustes-based approach to studying craniofacial dysmorphology in unilateral coronal synostosis and quantitatively describe bony patterns in this disorder, in order to better understand the associated fronto-orbital and sphenotemporal deformities.

Methods: Forty-one unilateral coronal synostosis (UCS) patients and 41 age- and sex-matched controls underwent high-resolution computed tomography imaging. Thirty-one anatomical landmarks were labeled on each imaging set. Landmarks were used to calculate angle, lengths, and define fronto-orbital and sphenotemporal anatomical curves. A validated geometric morphometric workflow was used to perform a Procrustes superimposition to register landmarks into a common space and perform a principal components analysis.

Results: Supraorbital bar curvature was significantly increased ipsilateral to the fused suture and decreased contralateral, P < 0.0001 for both sides. The sagittal sphenotemporal curve also showed ipsilateral increase in curvature (P < 0.0001) but there was no effect on the contralateral side (P > 0.05).

Conclusions: Geometric morphometric analysis revealed significant dysmorphology between UCS patients and controls. These results suggest bilateral changes in fronto-orbital curvature and ipsilateral changes in sagittal sphenotemporal curvature, which may be useful in further characterizing the dynamic craniofacial changes in UCS.