Intracranial aneurysm: CSF drainage

There are essentially two roles for cerebrospinal fluid drainage in cerebral aneurysm surgery. First, is the need to reduce brain bulk (by draining the ventricles) in order to limit retraction injury and facilitate access to aneurysms at the base of the brain (usually Circle of Willis). This is typically accomplished with a lumbar CSF drain.

Second, is the need to treat hydrocephalus in a patient with aneurysmal subarachnoid hemorrhage. In this situation, a ventricular drain is placed through a burr hole in the skull (although a lumbar drain may be used if the physician is certain that the hydrocephalus is communicating and not obstructive). The ventricular drain allows for ongoing CSF drainage to control intracranial pressure, and can also be used to reduce ventricular size and brain bulk during craniotomy for aneurysm treatment.

Finally, the anesthesiologist should be aware of low level evidence suggesting that CSF drainage may reduce symptomatic vasospasm and improve outcome in patients with aneurysmal subarachnoid hemorrhage (1).


  1. Panni P, Fugate JE, Rabinstein AA, Lanzino G. Lumbar drainage and delayed cerebral ischemia in aneurysmal subarachnoid hemorrhage: a systematic review. J Neurosurg Sci. 2015 Feb 4. [Epub ahead of print] PubMed PMID: 25649064.