Facial and Cranial Symmetry after One-Piece Fronto-Orbital Advancement with Distraction for Isolated Unilateral Coronal Synostosis

Abstract

Background: The surgical correction of unilateral coronal synostosis (UCS) aims to achieve longstanding facial and cranial symmetry. The authors hypothesized that endocranial morphology correction achieved by one-piece fronto-orbital advancement with distraction osteogenesis (FODO) could alleviate facial asymmetry because endocranial morphology is thought to be its major determinant. This study aimed to quantitatively analyze the changes in supraorbital and midfacial symmetry after FODO.

Methods: The authors included 27 patients with UCS who underwent FODO between May of 2008 and November of 2019. The supraorbital, midfacial, and orbital symmetry ratios and the endocranial and midface angles were measured using computed tomography images.

Results: The mean follow-up period was 3.7 ± 1.9 years. The supraorbital shape became symmetric after FODO; the supraorbital distance ratio changed from 0.88 ± 0.04 to 0.98 ± 0.03 ( P < 0.001). The endocranial angulation improved from 167.5 ± 5.0 degrees to 174.4 ± 3.4 degrees ( P < 0.001) and the midface angulation decreased from 6.6 ± 2.2 degrees to 2.6 ± 1.9 degrees ( P < 0.001). In the long-term follow-up analysis (5.9 years), the endocranial angle experienced a slight relapse (-1.4% ± 0.9%) and supraorbital symmetry experienced a -2.0% ± 3.9% relapse. The midface angle continued to improve over the follow-up periods, but it was not statistically significant ( P = 0.121).

Conclusions: The authors' observations indicate that FODO produced satisfactory outcomes in correcting supraorbital retrusion and midface asymmetry. In addition, FODO may allow anterior cranial base remodeling and help relieve midface and skull base angulation. Therefore, FODO can be a good therapeutic strategy for correcting supraorbital and facial asymmetry in patients with UCS.