Hypotelorism in Metopic Craniosynostosis: Persistent Undercorrection Following Open Cranial Vault Remodeling

Metopic craniosynostosis occurs due to premature fusion of the metopic suture, preventing normal lateral expansion of the frontal bones and resulting in trigonocephaly and hypotelorism. Metopic craniosynostosis with trigonocephaly is commonly treated with open fronto-orbital advancement and cranial vault remodeling (FOA/CVR). Although this procedure improves cranial contour, it does not directly widen the medial orbital walls, and its effect on hypotelorism remains uncertain. This study evaluated changes in bony interorbital distance (BIOD) and related craniometric parameters after standard FOA/CVR in patients with isolated metopic craniosynostosis. A retrospective single-institution study was performed of 19 pediatric patients with isolated metopic craniosynostosis who underwent open FOA/CVR from 2012 to 2019. Patients with syndromic craniosynostosis, multisuture synostosis, or minimally invasive repair were excluded. Pre- and postoperative CT scans were reviewed, and axial measurements were obtained, including BIOD/interdacryon distance, interzygomaticofrontal suture distance, bilateral orbital rim angles, and endocranial bifrontal angle. Pre- and postoperative values were compared, and interdacryon distance was compared with age-matched normative values using t tests. Mean age at surgery was 299 days, and mean postoperative imaging follow-up was 469 days. Interdacryon distance increased significantly after FOA/CVR from 13.35 mm to 14.81 mm (P=0.0296), and interzygomaticofrontal distance increased from 68.46 mm to 77.54 mm (P=0.0005). Orbital rim angles and endocranial bifrontal angle did not significantly change. Despite improvement, interdacryon distance remained significantly below age-matched normative values. Standard open FOA/CVR produces measurable improvement in BIOD; however, undercorrection of hypotelorism remains common at least 1 year postoperatively.