Modern concepts of CSF disorders in monosutural craniosynostosis

INTRODUCTION: Although hydrocephalus is randomly encountered in monosutural craniosynostosis (CS), CSF disorders may present more subtly and accompany these pictures. Indeed, dilation of subarachnoid spaces is frequently reported. The pathogenesis of these disorders is still under debate, as well as their prognostic significance. METHODS: A thorough review of the literature has been performed. Accordingly, pathogenic theories, eventual impact of surgical strategy, and prognostic significance are discussed. RESULTS: Most data come from scaphocephaly and trigonocephaly. Focal dilation of subarachnoid spaces is the most encountered CSF disorder in monosutural CS, followed by general dilation of subarachnoid spaces. Arachnoid cysts are exclusively associated to trigonocephaly. On the other side, overt hydrocephalus is a fortuitous occurrence, its pathogenesis being unrelated to monosutural CS. Pathogenesis of these CSF disorders has been related to CSF malabsorption, secondary to venous hypertension, and compensatory phenomenon. However, it is likely that local mechanisms, namely local venous hypertension and passive expansion, may better explain these pictures. Dilation of subarachnoid spaces usually resolve or at least improve after cranial remodeling and expansion. On the other side, arachnoid cysts may enlarge after fronto-orbital advancement. CONCLUSIONS: Future study should clarify the pathogenesis of CSF disorder in monosutural CS and possibly assess the risk of raised intracranial pressure if the CS is left untreated. Furtherly, the impact on timing and surgical strategy should be carefully explored.