Generalised post-operative cerebral vasospasm is a major factor in delineating poor operative results following direct ruptured intracranial aneurysms. Continuous monitoring of intracranial pressure seems to be particularly helpful on such occasions, and intracranial compliance determination as well. High intracranial compliance values suggest that even small intracranial volume increases may induce rapid intracranial pressure increase and situations likely to produce neurological deterioration.