Globe protrusion and interorbital divergence in syndromic faciocraniosynostoses

Purpose: The aim of this study was to quantify the relationship between globe protrusion (GP), length of medial and lateral walls, interzygomatic distance, and interorbital angle in syndromic faciocraniosynostoses. Methods: The axial slices of computed tomography of the orbits of 43 patients with faciocraniosynostosis (31 with Crouzon syndrome and 12 with Apert syndrome) and 23 control subjects were measured with the Image J software. The following 5 variables were quantified: The degree of GP, the length of the medial and lateral walls, the interzygomatic distance, and the interorbital angle. Results: Independent t-Tests revealed significant differences between the patients and the controls regarding the mean values of all variables measured. The degree of GPwas better correlatedwith the interorbital angle (r=0.81) than with the medial wall length (r=0.73). No correlation was found between GP and lateral orbital wall length. Conclusions: In syndromic faciocraniosynostoses, GP is highly correlated with the interorbital angle. The increment in the interorbital angle is a natural geometric consequence of the fact that a decrease in the orbital depth is not adequately compensated by an increase in the distance between the lateral orbit rims.