Table 3.

Update classification of the spinal arteriovenous malformation (AVM); AVF: arteriovenous fistula.

Type	Definition
1	Dural AVF
2	Intramedullary glomus-type AVM
3	Intramedullary juvenile AVM
4	Perimedullary AVM
4a	A simple extramedullary fistula fed by a single artery
4b	An intermediate-sized fistula with mono- or bipedicled feeding arteries and dilated drainage veins
4c	Giant fistulas with multipedicled arteries of large caliber and dilated large varix
5	Extradural-paraspinal AVM/AVF
5a	With medullary venous drainage
5b	Without medullary venous drainage