Fundamentals of Orbital Hypertelorism and Frontonasal Skull Dysplasia

Frontonasal dysplasia (FND) is a rare congenital condition of midline craniofacial bone and soft tissue malformations resulting from aberrant early embryogenesis. The majority of cases of FND are sporadic, and its clinical presentation and severity are highly variable. Patients may present with true orbital hypertelorism, bifid nose, broad nasal root, cleft lip and palate, cleft of the alae nasi, anophthalmia, eyelid malformations, anterior cranium bifidum occultum, and widow’s peak of the frontal hairline, among other features. Recent advances in genomic testing coupled with studies of developmental mechanisms influenced by various mutations have provided new insights into the etiology of diverse FND subtypes. Orbital hypertelorism is a complex and variable craniofacial abnormality often found in FND that is typically treated with either box osteotomy or facial bipartition. The application of virtual surgical planning to the treatment FND and orbital hypertelorism has improved surgical accuracy and outcomes as well as operative times.