Table 1.

Late-onset idiopathic aqueductal stenosis— inclusion criteria

I.	Age > 18 years
II.	Radiological findings on conventional magnetic resonance imaging (MRI):
	- supratentorial ventricular dilatation;
	- comparatively small fourth ventricle;
III.	Radiological findings: cerebrospinal flow absence at the aqueduct documented by phase-contrast MRI and/or obvious supratentorial ventriculomegaly associated with downward bulging of the third ventricle floor and/or cerebrospinal fluid (CSF) pathway obstruction at the aqueduct visible on T1 and T2 sagittal sequences
IV.	Suspected hydrocephalus neurological condition
V.	No previous shunting procedure
VI.	No other neurosurgical disease associated with Late-onset Idiopathic aqueductal stenosis
VII.	Endoscopic third ventriculostomy performed from 2003 to 2008