Abstract
Hydrocephalus is usually defined as the condition of ventricular dilatation due to the overproduction of cerebrospinal fluid[CSF] or dysfunction of absorption. The pattern of the CSF circulation may change after a cranioplasty secondary to previous decompressive craniectomy for refractory intracranial hypertension after head injury. The effect of the cranioplasty on CSF hydrodynamics has not been explored exactly. We report two cases of acute hydrocephalus developed after cranioplasty and discuss about the clinical importance with review of literatures.