0:00

Well, here we've got a 32-year-old female with

0:03

mid back pain for over a year.

0:06

I know this is one of your favorite diagnoses because

0:09

it's a diagnosis you taught me about.

0:11

And we've got a Sagittal T2 spin echo on the left,

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a Sagittal T1 anatomy image in the middle

0:20

made a little brighter for the audience.

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On the right, we've got an axial T1 weighted image,

0:26

and the patient has had a surgical procedure because

0:28

the posterior arch complex is missing.

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And as we look at the sagittal projection,

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the opisthion, which is normally down here,

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here's the basion, the episternum should be over here.

0:41

Now,

0:42

it's risen up because they've taken off

0:44

some bone in the back of the neck.

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So, as a radiologist,

0:48

I'm too involved in a case like this,

0:51

and I've got a strong neurosurgical background

0:54

from working with you all these years.

0:56

But I'm not a neurosurgeon.

0:58

I just play one on TV.

0:59

But at least I'm thinking a little bit like

1:01

a neurosurgeon now, thank goodness.

1:04

And here's a Sagittal T2 weighted image,

1:06

and I'm struck immediately by the syrinx.

1:09

So I'm saying to myself, okay, syrinx.

1:11

They didn't tell me why they did this decompression.

1:14

I'm thinking to myself, okay, well,

1:15

maybe it's a tumor. Well,

1:16

I don't see a mass appendoma or astrocytoma.

1:20

Well, maybe it's trauma. Well,

1:21

there's no history of trauma.

1:23

The vertebrae all look fine.

1:25

The alignment is pretty good,

1:27

so that doesn't really fit.

1:28

And the patient's had an operation that I know is

1:31

usually performed for decompression of the cranio

1:35

cervical junction. So I'm thinking, okay,

1:37

the patient probably had a Chiari malformation and had

1:41

a syringohydromyelia. So the question now arises,

1:47

does this syrinx still belong there?

1:50

And then B, why does she have mid back pain?

1:53

And then maybe, C,

1:55

what's going on?

1:56

And I'm having a hard time figuring out without

1:59

you what's going on. Right, well,

2:02

you described the operation,

2:04

and it's a common one for decompression of Chiari,

2:08

which includes a suboccipital craniectomy and

2:12

generally a C1 laminectomy, maybe even lower,

2:15

depending on how low the tonsils are.

2:17

And that's what we have in this case.

2:20

Now, remember,

2:22

in other connections we've talked about, okay?

2:25

One thing we want to look at is if

2:26

it's a decompressive surgery,

2:28

has decompression been achieved? Okay?

2:30

Is one of the things the surgeon is interested in.

2:33

So we want to look at that.

2:34

But there's another question in this case, you'd say,

2:37

well, is decompression adequate?

2:39

But can decompression be too good?

2:41

Well, it might be okay.

2:43

You can see that what's occurred here.

2:46

Let me get you okay.

2:47

There you go. All right,

2:49

so the bone removal is here,

2:51

really up to the equator of the cerebellum.

2:55

Okay. Pretty high. That's correct.

2:57

Now, generally speaking,

2:58

the goal is to decompress the foramen magnum and

2:59

the tonsils and do the C1

3:02

laminectomy. About how high would you take it?

3:05

Well, as I said,

3:06

if you try to keep it pretty low okay.

3:08

Because the foramen magnum and the tonsils,

3:11

if they're decompressed, then you're opening that CSF.

3:14

You want to reestablish CSF flow.

3:16

And if you decompress the foramen magnum C1,

3:20

you usually have done that,

3:21

and you actually will open dura, look at the tonsils,

3:24

and I would actually open and look at the CSF

3:28

coming out of the foramen magnum before I would

3:30

start closing to make sure I had reestablished flow.

3:33

Okay. Now, in this instance,

3:35

you look there and you say, well, okay,

3:37

so there was a good decompression.

3:40

But this still looks kind of tight right here.

3:43

Okay. The tonsils are kind of hanging down, right?

3:45

So what's occurred is that the cerebellum has dropped

3:49

down because there's maybe a little

3:51

bit over vigorous decompression,

3:53

and you've reconstituted the obstruction

3:56

at the skull base,

3:58

and that is known as cerebellar tonsillar ectopia.

4:01

Great article,

4:02

I believe from 1990 by Langston Holly and Ulrich

4:06

Batstorf really describes this very well.

4:08

And it's a not very widely recognized cause of failure

4:13

and reconstitution not only of the obstruction,

4:16

but of the syrinx.

4:17

So this syrinx never went away or came back.

4:19

So the tonsils and everything's kind of sagging down,

4:23

right? So called cerebellar ptosis.

4:25

And if the operation was a successful operation,

4:28

shouldn't the syrinx shrink on its own?

4:30

Or do you have to actually put a tube in and

4:32

decompression? No, we used to do that.

4:34

I mean, when I started in neurosurgery,

4:36

we would do that. That is,

4:37

we would do our decompression,

4:38

and then we'd actually go and do a little

4:40

myelotomy and put a tube in.

4:42

But really, if you get a good decompression,

4:44

the syrinx goes away. So I stopped doing that,

4:46

and I think most people stopped doing that a while

4:48

ago. So if you have a good decompression,

4:51

you should at least stabilize and hopefully reduce

4:54

the size of the syrinx.

4:55

And this one, I think,

4:57

probably went away some and then came back.

4:59

And that's why the patient's doing poorly again.

5:02

And this back pain. Okay, remember syrinx,

5:05

central cord, right upper extremities,

5:07

cape-like distribution of symptoms.

5:10

That's what a syrinx exam is.

5:13

And pain radiating in the cervical spine,

5:16

C5-6 and a central C5-6 disc will do the same thing.

5:20

Interscapular pain. So you get referred pain.

5:23

So this back pain thing is something you'll

5:25

actually hear pretty commonly,

5:26

even though the problem is in the neck.

5:27

Yeah, typical mid-back pain history,

5:30

which is very misleading.

5:31

You don't really put it together unless you're

5:33

a neurosurgeon, but the whole thing fits.

5:35

So an example of

5:37

over-vigorous decompression,

5:40

episternum too high cerebellar ptosis with

5:43

sagging of the cerebellar tonsils,

5:45

the syringohydromyelia has not resolved,

5:49

and this is the cause of the patient's mid-back

5:52

interscapular pain. Let's do another one, shall we?