Facial twist (asymmetry) in isolated unilateral coronal synostosis: does premature facial suture fusion play a role?

BACKGROUND Unilateral coronal synostosis (UCS) often causes notable facial twist in affected patients. This condition occurs when the midface deviates toward the synostotic side, and the lower face deviates away from the synostotic side. The exact underlying mechanism for this phenomenon remains unclear. It has been proposed that premature fusion of facial sutures may play a role in the formation of facial twist. The purpose of this study was to determine whether asymmetrical facial suture fusion is present in patients with UCS. METHODS A single-center retrospective study was designed. Our study group consisted of 23 patients with a confirmed diagnosis of isolated UCS. Our control group consisted of 17 age-matched patients with deformational plagiocephaly and 11 normocephalic control subjects. The computed tomography scans of the faces were examined for the presence of facial suture fusions on both synostotic and nonsynostotic sides. All results with P < 0.05 were considered statistically significant. RESULTS We found an increased incidence of fusion of the frontomaxillary, nasofrontal, and nasomaxillary sutures on the side of synostosis in UCS when compared with the nonsynostotic side and when compared with patients with deformational plagiocephaly or normocephalic patients. CONCLUSIONS Asymmetrical premature fusion of facial sutures can potentially be contributing to the facial twist that is seen in patients with UCS.