Orbital Volumetric Analysis in Patients With Unicoronal Craniosynostosis: A Comparison Between Distraction Osteogenesis and Fronto-Orbital Advancement

Background: Unicoronal craniosynostosis is associated with orbital restriction and asymmetry. Surgical treatment aims to both correct the aesthetic deformity and prevent the development of ocular dysfunction. We used orbital quadrant and hemispheric volumetric analysis to assess orbital restriction and compare the effectiveness of distraction osteogenesis with anterior rotational cranial flap (DO) and bilateral fronto-orbital advancement and cranial vault remodeling (FOAR) with respect to the correction of orbital restriction in patients with unicoronal craniosynostosis.

Methods: A retrospective review of all patients with a diagnosis of unicoronal craniosynostosis and treated with either DO or FOAR from 2000 to 2019 was performed. Preoperative and postoperative total orbital volumes, as well as quadrant and hemispheric volume ratios, were calculated from 3-dimensional head computed tomography scans. Selected preoperative and postoperative orbital measurements, including the maxillary length of the orbit (MLO; zygomaticofrontal suture to the top of zygomatic arch) and the sphenoid length of the orbit (SLO; the top of sphenoid suture to the top of zygomatic arch), were also obtained.

Results: Data were available for 28 patients with unicoronal craniosynostosis. Mean preoperative total orbital volume was significantly smaller on the synostotic side compared with the nonsynostotic side (10.94 vs 12.20 cm3, P = 0.04). Preoperative MLO and SLO were significantly longer on the synostotic side compared with the nonsynostotic side (MLO: 20.26 vs 17.75 mm, P < 0.001; SLO: 26.91 vs 24.93 mm, P = 0.01). Distraction osteogenesis and FOAR produced significantly different changes in orbital quadrant and/or hemispheric volume ratios on the nonsynostotic side but not on the synostotic side.

Conclusions: Before correction, patients with unicoronal craniosynostosis have significantly smaller total orbital volumes on the synostotic side compared with the nonsynostotic side and significantly greater MLO and SLO on the synostotic side compared with the nonsynostotic side. There is no significant difference between DO and FOAR with regard to correcting the observed orbital restriction in these patients.