Trigonocephaly-associated hypotelorism: an assessment of orbital shapes and dimensions

Trigonocephaly occurs due to the premature fusion of the metopic suture. The aim of this study was to document the orbital morphometry of patients with trigonocephaly compared to controls, and to classify the different morphological appearances of the orbits in trigonocephaly. Preoperative two-dimensional computed tomography scans of 15 patients with non-syndromic isolated trigonocephaly (13 male, two female; median age 11 months) and eight controls (four male, four female; median age 22 months) were digitized and analysed. Orbital height, width, and surface area (left and right) and inter-orbital distance were measured. For the trigonocephaly patients, orbital morphology was classified into various shapes (rhomboid, kidney bean, teardrop, oval, pear, pentagon, hexagon, and triangular) and assessed across three age groups. There was no significant difference in any of the morphometric measurements between the trigonocephaly and control groups. In the control group, inter-orbital distance was significantly and strongly correlated with orbital width (left, r = 0.799; right, r = 0.712), height (right, r = 0.736), and surface area (left, r = 0.903; right, r = 0.853) (all P < 0.05), while no significant correlation was observed between inter-orbital distance and the orbital measurements in the trigonocephaly group. The most commonly observed orbital shapes by age group were kidney bean in the <12 months age group and pear and oval in the 12 to <36 months age group. The study findings could assist craniofacial and reconstructive surgeons in selecting the surgical technique needed to obtain as near to normal orbital morphology and function as possible.