Table 1.

Djindjian and Merland’s classification (1978)

Type I	Antegrade or retrograde drainage into a sinus or a meningeal vein
Type II	Antegrade or retrograde drainage into dural sinus with cortical venous reflux
Type III	Drainage solely into cortical veins
Type IV	Drainage into one or more large venous lakes (dural or subdural) that act as a mass lesion (supra- or infratentorial venous lake)