Influence of aneurysm location on the development of chronic hydrocephalus following SAH.

The incidence of chronic hydrocephalus was analysed in a series of 204 patients with aneurysmal subarachnoid haemorrhage (SAH). Its development was significantly related to the quantity of subarachnoid blood, but even more to the location of the haemorrhage and to the aneurysm site. Hydrocephalus was more frequent in patients under poor initial condition. Whereas intracerebral haemorrhage did not increase the risk of chronic cerebrospinal fluid (CSF) resorption disturbances. Patients with intraventricular haemorrhage or voluminous haemorrhage in the basal cisterns have a significantly higher risk of such a complication. In this series 30 (15%) patients developed chronic hydrocephalus and required shunting. Surprisingly, in our series a shunt was never needed in patients with aneurysms of the middle cerebral artery (MCA). SAH from an aneurysm of the internal carotid artery (ICA) also never caused a shunt-dependent hydrocephalus except in cases with accompanying intraventricular haemorrhage. The percentage of chronic hydrocephalus was relatively high (19%) in patients with anterior communicating artery (ACoA) aneurysms but definitely highest in patients with an aneurysm of the vertebrobasilar (VB) system (53%).