0:01

When we think about the various vascular

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lesions of the spinal canal,

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we remember that the most common of these

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is the dural arteriovenous fistula.

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In this situation, there is a fistula out in the nerve

0:14

root sleeve. Actually, in the dura,

0:16

or extradural relocated. What we see, however,

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on imaging of the spine are dilated veins on

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the surface of the spinal cord, within the

0:25

intradural extramedullary compartment.

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And that's the most common of the vascular

0:31

malformations of the spinal canal.

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There are other vascular lesions that

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occur within the spinal cord,

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including true arteriovenous malformations,

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so-called type 2.

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And in addition, you may have a cavernous malformation.

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These would be intradural

0:48

intramedullary lesions.

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And in the case of a cord arteriovenous malformation,

0:53

you may have veins that are, again, outside the

0:55

spinal cord. With respect to the most common,

0:58

that being the dural AV fistula,

1:01

this is usually seen in elderly men that

1:04

present with a myelopathy over the

1:06

course of weeks to months.

1:08

Usually is not really associated with any pain.

1:12

This is a slide of a patient who has

1:16

a dural arteriovenous fistula.

1:18

You'll note that the patient has abnormal signal

1:21

intensity within the spinal cord.

1:24

So there is an intradural intramedullary abnormality,

1:29

and that is usually venous congestion within

1:33

the spinal cord leading to the myelopathy.

1:35

Posterior to the spinal cord,

1:37

you'll see all these little squiggly things.

1:39

And these squiggly things are blood vessels.

1:42

In point of fact, they are veins.

1:43

They are draining veins from

1:45

the dural AV fistula.

1:46

What we do not see is the actual fistula.

1:49

That is very hard to resolve

1:51

on MRI scan, it would require spinal MRA.

1:55

But this is usually out in the nerve root sleeve,

1:59

not on a section that's showing the spinal cord.

2:01

Here on the right hand side is a different case,

2:04

just a little bit more dramatic,

2:05

where you see all these things that look like

2:07

worms almost on the surface

2:09

of the spinal cord. Again,

2:11

those are all blood vessels that are

2:14

draining from the dural AV fistula.

2:16

So you have arterialized flow in the veins of

2:19

the spinal canal from this fistula that's

2:23

occurring in the dura. So another example,

2:25

different patient.

2:27

Lots of things occurring outside the spinal

2:29

cord with squigglies that are the blood

2:33

vessels of a dural AV fistula.

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So this is the Spetzler classification

2:39

of spinal vascular malformations.

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This is his type I in which there is a

2:46

dural basis to the arterial fistula.

2:49

So we're out in the nerve root sleeve here at

2:51

the dura level. Here's extradural vessels.

2:55

And we have a connection between

2:57

an artery and a vein,

3:00

which is on the surface of the spinal cord.

3:03

So although the lesion is extradural,

3:06

the manifestation of it with the enlarged

3:08

veins is intradural extramedullary.

3:12

And there are two different varieties of type I.

3:14

Those with single feeders or multiple feeders.