Rationale for lumbar drains in aneurysmal subarachnoid hemorrhage

The amount of blood in the basal cisterns is predictive for the final outcome after aneurysmal subarachnoid hemorrhage (SAH) and clinical problems such as delayed cerebral ischemia and angiographic vasospasm. A lumbar drainage presents an additional, physiologically appealing treatment. In contrast to an external ventricular drain, stasis of clots is thought to be prevented and clearance of the basal cisterns accelerated. In theory, patients with higher clinical grades and dense layers of subarachnoid blood should benefit most.

A positive signal but so far no conclusive evidence for lumbar drains in SAH is available from retrospective data. Two large series exist, one after clipping and one after endovascular coiling of the aneurysm leading to the index hemorrhage. The only high-quality large prospective trial failed to prove a better neurologic outcome at 6 months, but investigated predominantly good grade patients with less severe hemorrhage. Further data from another phase III trial is still pending. A concern on the safety of lumbar drains is not supported.

At present, no definite conclusions and recommendations on lumbar drains in patients after aneurysmal SAH are warranted.