Classical pterional compared to the extended skull base approach for the removal of clinoidal meningiomas.

We reviewed a series of 46 consecutive, surgically treated patients with clinoidal meningioma to compare the classical pterional approach (32 patients) to an extended approach including extradural clinoidectomy and removal of the optic canal roof (14 patients). The tumor size and Al-Mefty type, the extension into the optic canal, the time to identification of the optic nerve and internal carotid artery, and the visual outcome were evaluated. Complete tumor resection was obtained in 81% of patients with the classic pterional approach compared to 93% of patients using an extended approach. The extended skull base approach should be used routinely in clinoidal meningiomas >2.5 cm in size, in ones of Al-Mefty type III, and in all patients with tumor extension into the optic canal.

Is endoscopic third ventriculostomy an internal shunt alone?

OBJECTS: This study was made to define the mechanism of endoscopic third ventriculostomy (ETV) in the various forms of hydrocephalus. METHODS: One hundred and forty patients with various forms of hydrocephalus treated by ETV are reviewed. The series includes 75 cases (53.5%) of triventricular obstructive hydrocephalus (group 1), 20 (14.3%) with hydrocephalus following CSF infection or hemorrhage (group 2) and 45 (32.3%) with idiopathic normal pressure hydrocephalus (group 3). Factors which have been considered include type and etiology of the hydrocephalus, intraoperative evidence of downward and upward movement of the third ventricular floor after the stomy, patient outcome and rate of shunt-independent cases. RESULTS: The overall rate of successful ETV was 79.3% (111/140 shunt-free patients). The success rate was 88% (66/75) in group 1, 60% (12/20) in group 2 and 73.4% (33/45) in group 3. The intraoperative finding of significant movement of the third ventricular floor after the stomy was evidenced in 121/140 cases (86.4%) and particularly in all cases of group 1, in 9/20 (45%) of group 2 and in 37/45 (82%) of group 3. CONCLUSIONS: The relatively high rate of success of ETV in various forms of hydrocephalus and the intraoperative finding of mobility of the third ventricle floor after the stomy suggest that the first mechanism of the ETV is the restoration of pulsatility of the ventricular walls. This results in restoration of the CSF flow from the ventricular system into the subarachnoid spaces and normalization of the CSF dynamics. Accordingly, ETV is not only an internal shunt, but it primarily influences the capacity of the brain pulsatility to ensure CSF flow.