Decreased shunt dependency by opening the lamina terminalis in patients with ruptured intracranial aneurysms?

Introduction: Opening of the lamina terminalis (LT) during surgery for ruptured intracranial aneurysms is a technique to lower the intracranial pressure and facilitate preparation by removing cerebrospinal fluid (CSF). Until now it remains unclear whether opening of the third ventricle reduces the incidence of posthermorrhagic shunt-dependent hydrocephalus. Methods: Between January 1992 and June 1996, 217 consecutive patients (142 female, 75 male, mean age 54 years) with acute aneurysmal subarachnoid hemorrhage were treated by aneurysm clipping. Anterior ventriculo-cistemostomy by opening of the LT was performed in 187 of the 217 individuals (86%). Severity and distribution of the bleeding according to the Fisher scale was similar in patients with and without opening of the LT. Results: Of the 217 patients, 48 (22%) required permanent shunting. Twenty percent of the 187 patients with anterior ventriculo-cisternostomy developed shunt-dependency as compared to 37% of the 30 patients without opening of the LT. Patients with intraoperative opening of the LT were shunted after a mean of 6.5 weeks following SAH, and thus later than in patients without anterior ventriculo-cisternostomy (4.5 weeks). Opening of the LT did not influence vasospasm or clinical outcome. Conclusion: These results suggest, that opening of the LT during the surgical dissection of a ruptured cerebral aneurysm in the anterior part of the circle of Willis may lower the incidence of shunt-dependent hydrocephalus