MATERIAL and METHODS: This was a clinical, retrospective study that included 72 patients with aneurysmal subarachnoid hemorrhage (aSAH). The patient group that underwent aneurysm clipping with only extensive cisternal drainage of the subarachnoid blood clot was defined as the non fenestrated lamina terminalis group (NonFLT group, n=39). The patient group that underwent aneurysm clipping with extensive cisternal drainage of the subarachnoid blood clot combined with microsurgical fenestration of LT was defined as the fenestrated lamina terminalis group (FLT group, n=33). All patients were operated by the same experienced neurovascular surgeon, the senior author of this article (MEU), and his colleagues. New cerebral infarct development was determined with computed tomography, Glasgow Outcome Score (GOS), clinical vasospasm rate and Hunt-Hess scale (H&H) grade before and after surgery and duration of hospital stay of the patients were assessed and compared.

RESULTS: A favorable clinical outcome was obtained from 51.2% of the NonFLT group patients and 72.66% of the FLT group patients. And FLT group patients have better GOS and H&H grade. Clinical vasospasm rate and duration of hospital stay were also significantly reduced in FLT group patients.

CONCLUSION: Wide fenestration of lamina terminalis as a cerebrospinal fluid diversion technique may be very beneficial in the surgical treatment of aneurysmal SAH. Keywords : Cisternal blood clot, Lamina terminalis, Subarachnoid hemorrhage, Symptomatic vasospasm