Rotation of the Ipsilateral Supraorbital Rim Around the Horizontal Axis in Unilateral Coronal Synostosis: A Craniometric Analysis of the Emergence Profile.

ABSTRACT

INTRODUCTION: Unilateral coronal synostosis (UCS) results in well-defined dysmorphic changes including sphenoid malposition yielding posterior displacement of the supraorbital rim. Although variation in the ipsilateral supraorbital rim emergence profile has been suggested, it has not been previously investigated. The authors sought to characterize the emergence profile of the ipsilateral supraorbital rim in UCS through craniometric analysis. METHODS: Thirty-five nonsyndromic UCS patients (0-18 months) with CT images obtained before operative intervention and 16 control patients (0-24 months, 32 orbits) were included. Craniometric measurements were performed to quantify the emergence profile of the ipsilateral supraorbital rim and locate the likely apex of rotation. RESULTS: The ipsilateral supraorbital rim was significantly rotated around the horizontal axis when measured in reference to the 0° vertical in UCS versus control patients by an average difference of 7.3° to 11.3° across age groups (P < 0.05). No significant effect modification was detected between age and UCS on ipsilateral supraorbital rim emergence profile (P > 0.05). Additional angles with vertices around the superior orbital circumference were then measured to locate the likely apex of rotation and revealed a significant decrease in the posterior orbital roof to 0° horizontal in UCS patients by an average of 9.3° to 22.1° in children under 1 year old (P < 0.01). CONCLUSION: Variation in the emergence profile of the ipsilateral supraorbital rim in UCS is quantified, and the apex of this rotation likely lies at the posterior orbital roof. The novel quantification and characterization of this deformity will better direct the operative approach and enable a more accurate correction.