Chronic hydrocephalus after subarachnoid hemorrhage. Role of lamina terminalis fenestration

The incidence of chronic hydrocephalus requiring cerebrospinal fluid shunting was analyzed for a prospective series of 55 consecutive patients with ruptured cerebral aneurysms who underwent fenestration of the lamina terminalis during early microsurgical aneurysm repair. We hypothesized that, by creating an anterior ventriculocisternostomy, fenestration of the lamina terminalis facilitates CSF dynamics and decreases the risk of subsequent hydrocephalus. Estimates from the most recently published studies indicate that an incidence of chronic post-SAM hydrocephalus (requiring shunt surgery) of 15 to 20% is representative for an average contemporary population of patients with aneurysmal subarachnoid hemorrhage. The lower incidence of chronic hydrocephalus observed in this series possibly reflects the favorable effect of lamina terminalis fenestration on CSF dynamics.