0:01

The other types of Spetzler vascular

0:04

malformations are much less common.

0:06

They include the Type II malformation in which there is

0:10

a true arteriovenous nidus within the spinal cord.

0:15

So the AVM nidus is in the cord.

0:17

It's intramedullary. However, they, too, may have enlarged

0:21

draining veins in the intradural extramedullary location.

0:26

This is the Type III or metameric type of vascular malformation.

0:30

In this case,

0:31

you may see arteriovenous malformation that is

0:35

within the bone, within the intradural extramedullary space,

0:40

as well as within the intradural intramedullary space.

0:44

So you're seeing portions that are in the

0:46

spinal cord outside the spinal cord,

0:48

but within the intradural space,

0:50

as well as outside the dura in the extradural space.

0:53

This is the so-called Type III juvenile metameric

0:57

Spetzler vascular malformation.

1:00

This is the Type IV vascular malformation.

1:02

In this case, it is truly an intradural extramedullary

1:07

abnormality. That is a fistula that is occurring outside

1:12

the spinal cord, within the dural space, showing both

1:17

enlarged artery and vein in the abnormality in

1:22

the intradural extramedullary location.

1:24

This is incredibly uncommon but is part

1:28

of that Spetzler classification.

1:30

Here is an example of a patient who has a hemorrhage

1:35

associated with a vascular malformation outside the

1:39

spinal cord presumed to be a Type IV fistula.

1:43

On this image, you see bright signal intensity from blood

1:46

products, as well as dark signal intensity

1:49

from high flow vascularity.

1:53

Here is the bright stuff which is the blood.

1:55

Here is the flow void, which is the

1:58

fistula between an artery and a vein

2:02

in the intradural extramedullary location.