INTRODUCTION: Temporal hollowing is a known late sequelae of fronto-orbital advancement (FOA) surgeries, and much work has highlighted the effect of soft tissue manipulation as a cause. However, bony manipulation including devascularization and undercorrection may also contribute to temporal hollowing. Currently no long-term quantitative assessments exist which evaluate the bony changes after FOA. We sought to objectively assess how such bony morphology changes overtime.
METHODS: A multicenter, Institutional Review Board–approved retrospective study identified craniosynostosis patients treated with FOA between 2008 and 2018 at Children’s Hospital of Pittsburgh or Children’s Hospital of Philadelphia. Syndromic and nonsyndromic patients with both early postoperative and late follow-up (>12 months) head computerized tomography scans were included. Scans were reconstructed, oriented in a standardized fashion, and manually segmented into surgical fragments that delineated the osteotomies of interest for a given. Two craniofacial surgeons confirmed all segmentations and data points of interest. Thirty-two data points and 56 discreet metrics were collected from each patient and evaluated for changes over time.
RESULTS: Twenty patients matched inclusion criteria (12 female:8 male). Craniosynostosis subtypes included metopic (7), unilateral coronal (6 right, 3 left), multisutural (2), sagittal (1), and sagittal and metopic (1). Mean age at surgery and time to follow-up scan were 1.4 and 2.8 years, respectively. Average growth of the inter-eurion distance and glab.-opistho. distance was 3.3% and 9.6%, respectively. The bandeau AP length increased 17.4%. Although average bitemporal width increased 9.0%, anterior bandeau width decreased by 4.1%, leading to a transverse deficiency in the anterior temporal region. The average initial zygomaticofrontal osteotomy offset was 3.9 mm laterally and 6.5 mm anteriorly; these remodeled, eliminating the gap. The average initial bandeau orbital width was 3.8 mm wider than the midface orbital width and decreased over time (≈39% loss of overcorrection). Data were significant to P < 0.05 by paired t test.
CONCLUSION: The long-term shape and position of the bandeau determine surgical success of FOA. We found that the skull continues to widen bitemporally after surgery; however, widening at the anterior temporal region is negligible. This is the first comparative demonstration of the bony contribution toward temporal hollowing in early and late postoperative patients.