Microsurgical Fenestration of the Lamina Terminalis Reduces the Incidence of Shunt-dependent Hydrocephalus after Aneurysmal Subarachnoid Hemorrhage

OBJECTIVE Hydrocephalus requiring shunt placement is a common complication after aneurysmal subarachnoid hemorrhage (aSAH). Previous investigations suggest that fenestration of the lamina terminalis during microsurgery for aSAH may be associated with a reduced rate of shunt-dependent hydrocephalus. We report a retrospective analysis correlating fenestration of the lamina terminalis with decreased shunt-dependent hydrocephalus after aSAH. METHODS During the past decade, 582 patients were admitted to our institution with aSAH. We compared the rate of shunting in patients operated on by a neurosurgeon (“index neurosurgeon”) who routinely fenestrated the lamina terminalis (>98% of his patients) with that in patients managed by 14 other neurosurgeons who rarely fenestrated the lamina terminalis (<5% of their patients) and by 6 interventional neuroradiologists. The total cohort was subdivided into two groups on the basis of surgical approach and microsurgical access to the lamina terminalis. Group A included frontosphenotemporal craniotomies, an approach in which the lamina terminalis is accessible, and Group B included other approaches in which the lamina terminalis is not accessible. Shunting rates of the index neurosurgeon and those of the other practitioners were compared within Groups A and B. Shunting rates were compared by logistic regression and multivariable analysis. This study design isolates the effect of fenestrating the lamina terminalis on the incidence of shunt-dependent hydrocephalus. RESULTS In Group A, the index neurosurgeon had a significantly lower rate of shunting, 2.3%, versus 12.6% for other practitioners (P = 0.011; odds ratio, 0.15). In Group B, in which the approach did not allow microsurgical fenestration of the lamina terminalis, there was no difference (P = 0.789) in the rate of shunting between the index neurosurgeon (10.0%) and other practitioners (13.2%). CONCLUSION Fenestration of the lamina terminalis appears to be associated with a decreased incidence of shunt-dependent hydrocephalus of more than 80% after aSAH. This straightforward microsurgical maneuver should be performed whenever possible during aneurysm surgery.