Frontal Hyperostosis in the Patients of Craniosynostosis After Cranial Distraction Osteogenesis.

Background: Conventional fronto-orbital advancement and distraction osteogenesis (DOG) have been used to treat craniosynostosis, both of which are considered effective. During the authors' practice, a phenomenon of frontal hyperostosis has been observed in the patients of craniosynostosis after DOG, which has yet to be reported in the literature. The purpose of this study is trying to identify the factors related to the phenomenon.
Materials and Methods: From 1997 to 2010, all patients of craniosynostosis undergoing DOG were reviewed. The patient's age at operation, consolidation period, numbers of distractor, distance of distraction, and duration from removal of the distractors to identification of the phenomenon on computed tomography were recorded. The phenomenon was considered positive when the hyperostosis appeared on the frontal bone, where it was neither the osteotomy site nor the previous position of distractor.
Results: A total of 61 patients were included in this study, including 26 syndromic and 35 nonsyndromic patients. Two syndromic and 6 nonsyndromic patients had the phenomenon. There was no statistical difference between the patients with and without the phenomenon in comparison with the age, number of the distractor, consolidation period, and the distance of distraction.
Conclusion: Frontal hyperostosis happened in some patients of craniosynostosis after DOG. Although no significant difference was demonstrated, the incidence of hyperostosis was higher in nonsyndromic patients and the patients of hyperostosis had shorter distance of distraction in both syndromic and nonsyndromic groups. Although the definite cause was unknown, we should pay attention to the phenomenon after distraction.