The APERT Severity Scale: A Quantitative Tool for Risk Stratification in Apert Syndrome

BACKGROUND: Apert syndrome is a rare congenital disorder characterized by craniosynostosis, midface hypoplasia, and syndactyly. The multisystem complexity and lack of standardized surgical guidelines complicate diagnosis and treatment. This study introduces a quantitative severity scale for Apert syndrome to support objective risk stratification and personalized care. METHODS: The authors retrospectively reviewed children with Apert syndrome who were at least 11 years of age and treated from 1988 through 2024. A 5-domain severity scale based on literature review and clinical data was developed. Scoring was performed using preoperative photographs and documentation. RESULTS: Of 65 identified patients, 37 (56.9%) met inclusion criteria. The mean follow-up age was 17.0 ± 5.0 years, with an average of 4.4 ± 2.2 craniofacial surgical procedures. Patients were scored from 1 (least severe) to 3 (most severe) in 5 domains: airway compromise, pressure (intracranial), eyes, retrusion of midface, and turribrachycephaly (APERT), with total scores ranging from 5 to 15. Severity categories were defined as mild (5 to 7), moderate (8 to 11), or severe (12 to 15). Fifteen patients (40.5%) had mild disease, 20 (54.1%) moderate, and 2 (5.4%) severe, with a mean score of 8.1 ± 1.8. Higher APERT scores correlated with increased surgical frequency ( r = 0.851; P < 0.001). Subscores in airway, pressure, eyes, and skull shape were also predictive. A score of 9 or greater predicted 6 or more surgical procedures with 100% sensitivity and 86.7% specificity. CONCLUSIONS: The APERT score is the first quantitative classification of Apert syndrome severity, correlating with phenotypic burden and surgical volume. The APERT score may improve clinical communication, institutional comparisons, and risk-based treatment planning.