Objective Analysis of Fronto-Orbital Dysmorphology in Unilateral Coronal Craniosynostosis

Correction (and over-correction) of asymmetries of the orbital shape and brow position in unilateral coronal craniosynostosis (UCS) is critical to successful fronto-orbital advancement. Here we quantify and three-dimensionally assess fronto-orbital irregularities in UCS patients compared to controls.Twenty-three patients with UCS evaluated at the Children's Hospital of Pittsburgh between 2006 and 2016 were age and gender-matched to controls. Computed tomography scans were reconstructed and evaluated for orbital metrics. A three-dimensional heat map of orbital regions was generated and evaluated for shape differences.Brow protrusion of the orbit ipsilateral to the synostotic suture did not differ significantly from healthy controls. Orbital height was significantly increased while orbital width was decreased on the UCS ipsilateral side compared to the contralateral side and controls. The ipsilateral cornea was overprojected relative to the brow and the infraorbital rim, but similar to controls relative to the lateral rim. The contralateral orbit had increased brow protrusion with decreased orbital height. The cornea was underprojected relative to the brow, but overprojected relative to the lateral orbital rim and similar to controls at the infraorbital rim. Three-dimensional comparison demonstrated significant overprojection of the contralateral brow, with some more mild and inconsistent underprojection of the lateral aspect of the ipsilateral brow.Key orbital and brow differences exist between the affected and unaffected sides in UCS. This study provides quantitative data that further characterize the orbital dysmorphology observed in UCS and identifies unique aspects of the diagnosis that should be taken into consideration during surgical planning.