Pseudoclosure of Anterior Fontanelle by Wormian Bone in Isolated Sagittal Craniosynostosis

AIMS AND OBJECTIVES: Although syndromic craniosynostosis is one of the causes for early closure of the anterior fontanelle, there is no literature on the incidence and causes of fontanelle closure in isolated single-suture craniosynostosis. The objective of this study was to review the incidence of fontanelle closure by a wormian bone in isolated, nonsyndromic sagittal craniosynostosis. MATERIALS AND METHODS: Intraoperative records of 100 consecutive children under 1 year of age, operated for isolated sagittal synostosis over a 14-year period (1987- 2000), were reviewed to identify the presence of a wormian bone closing the anterior fontanelle. RESULTS: The median age at surgery was 4.2 months with a range of 1.9-11.7 months. Intraoperatively, a wormian bone was seen replacing the anterior fontanelle in 4 cases giving an incidence of 4%. CONCLUSIONS: A wormian bone can occupy the anterior fontanelle in children with isolated sagittal craniosynostosis giving the appearance of a 'closed fontanelle'.