Table 2.

Yakes AVM classification system [8].

Nidus Type	Description	Treatment Approach
Ia	Direct AVF	Mechanical occluding device
IIa	Typical AVM nidus	Transcatheter and direct puncture ethanol embolization
IIb	AVM nidus shunting into aneurysmal vein	Same as type IIa as well as coiling outflow vein
IIIa	Aneurysmal small vein where nidus resides in vein wall with single outflow vein	Coiling single aneurysmal outflow vein
IIIb	Type IIIa with multiple outflow veins	Coiling each outflow vein
IV	Tissue infiltrative AVM	Transcatheter or direct puncture embolization