0:01

Within our mnemonic of vitamin C and D,

0:03

that is vascular, infectious, traumatic, acquired,

0:06

metabolic, idiopathic, neoplastic,

0:08

congenital, and drugs.

0:09

We are now under the C of vitamin C and D

0:13

for congenital lesions.

0:15

And I've just shown a case of hydromyelia

0:18

associated with Chiari 1 malformation.

0:22

Here's another example of a patient who has the

0:24

classic pegging of the cerebellar tonsils

0:28

through the foramen magnum.

0:30

This shape is what we mean by pegging.

0:34

And again,

0:35

we would draw the line from the basion to the

0:39

episthenon and then measure the degree

0:42

of cerebellar tonsillar descent.

0:45

That number has been set at 5 mm or greater

0:49

for representing Chiari 1 malformation.

0:52

That said, we do see patients who have

0:54

greater than 5 mm of descent

0:56

where there is no crowding and the patient asymptomatic.

1:00

And we have patients who have 3 or 4 mm of descent

1:03

and the patient is symptomatic and

1:05

has a syrinx associated with it.

1:07

So these numbers are not necessarily absolute.

1:10

What we do see, in this case, is the expansion of the

1:13

spinal cord with the hydromyelia of

1:17

Chiari 1 malformation.

1:19

Again, this is because it's dilatation of the

1:22

central canal of the spinal cord,

1:25

which is the classic description of the

1:28

etiology of the cavity,

1:30

that is increase in the pressure in the spinal canal being

1:35

transmitted along the perivascular spaces

1:37

and decompressing into the central canal.

1:41

Chiari malformations are more common in women.

1:44

They occur in young adults and they have a multitude

1:47

of different potential symptoms that are associated

1:50

with them, including most commonly headaches,

1:53

dizziness,

1:54

tinnitus, or dysphasia, or odynophagia,

1:59

or other lower cranial nerve symptomatology.

2:02

Here is another example of the same.

2:05

Here you have a T1-weighted,

2:07

T2-weighted, and axial T2-weighted scan

2:10

where you just see on this post-gadolinium-enhanced

2:13

T1-weighted image, no evidence of enhancement.

2:16

You see a central syrinx in the spinal cord.

2:20

It's relatively short in this example.

2:22

And you see the tonsillar herniation.

2:24

On the axial T2-weighted scan,

2:27

enlargement of the spinal cord

2:29

with the central hydromyelic cavity of

2:33

Chiari 1 malformation. As I mentioned,

2:36

with the central canal nature of the hydromyelia,

2:41

you will get the central cord symptomatology of

2:44

muscular weakness, usually affecting the upper

2:46

extremities greater than the lower extremities,

2:49

impaired position sense, and impaired fine motor function.

2:54

If you have an equivocal case of a Chiari 1 malformation,

2:59

maybe at 4 mm, but it seems a little tight,

3:02

or maybe at 6 mm, but it doesn't seem tight,

3:05

it's helpful to perform the phase

3:08

contrast CSF pulsation study.

3:11

Here we have a patient who has a pretty classic

3:13

Chiari 1 malformation with an associated syrinx.

3:18

This is well demonstrated on the T1-weighted scan

3:22

with both the tonsillar pegging, as well as the

3:25

hydromyelic cavity or syringohydromyelia.

3:29

When one performs the CSF pulsation study,

3:32

you should be seeing bright signal intensity

3:35

and then dark signal intensity,

3:36

as you see here around the spinal cord that

3:40

would be present also at the skull base.

3:44

In this case, we are not seeing that normal CSF

3:47

pulsation because of the obstruction of normal

3:50

pulsation by the cerebellar tonsils within the

3:54

foramen magnum.

3:56

Contrast that with this case.

3:59

So here we have a patient,

4:01

the same patient who has undergone decompression.

4:05

So with the decompression, as I stated earlier,

4:10

you have the suboccipital decompression procedure.

4:14

You have the posterior arch of C1,

4:16

which has been removed, and you have the duraplasty,

4:21

which is the expansion of the dura to allow more CSF

4:25

to bathe the cerebellar tonsils.

4:27

Upon the performance

4:29

of the suboccipital decompression,

4:33

C1 posterior arch removal, and duroplasty,

4:37

you note that the patient's hydromyelic

4:41

cavity has decreased in size.

4:45

And now, we have a more normal appearance to the

4:50

pulsation posteriorly around the tonsils,

4:53

as well as anteriorly in front of the brainstem.

4:57

So let me just go back and show that slide

5:00

one more time of the previous example.

5:02

Here we have the size of the syrinx.

5:04

As you see, post-decompression

5:06

and the more normal appearance to the CSF pulsations.

5:11

If we go back to the pre-op examination, abnormal CSF

5:17

pulsation and abnormal enlarged hydromyelic cavity,

5:23

which subsequently is treated.

5:26

The hydromyelic cavity has been

5:29

described by Milhorat,

5:31

who is a neurosurgeon from approximately the 1970s.

5:36

Let me actually get the reference here.

5:38

Milhorat from 1999,

5:41

who looked at over 300 patients with Chiari 1 and

5:47

described the presence of

5:49

syringohydromyelia in 60% of cases.

5:52

I've since looked at the Johns Hopkins experience,

5:56

and our number is closer to about 36%.

5:59

And I think that's because we've gotten more comfortable

6:02

with calling asymptomatic Chiari 1 malformations.

6:07

You can get syrinx cavities within the spinal cord

6:12

without an associated Chiari 1 malformation.

6:15

Here's a patient who has normal cerebellar tonsils

6:19

which are above the foramen magnum.

6:21

Let me just draw that in.

6:22

So here's our basion to opisthion,

6:25

and you see that the tonsils are above that level,

6:31

and yet the patient has a cavity within the

6:34

spinal cord, which looks pretty clean.

6:37

If you see this on your degenerative disc

6:39

disease or post-trauma cases,

6:42

it behooves the radiologist to recommend

6:45

a post-contrast scan.

6:47

We just want to make sure we don't

6:48

see a tiny little nodule

6:51

that might suggest that this is a

6:55

hemangioblastoma, which can be relatively subtle.

6:59

So, if you see an isolated cord syrinx,

7:03

recommend post-contrast enhanced scan to see

7:06

whether there's any peripheral nodular enhancement

7:08

that would indicate that this represents

7:11

hemangioblastoma instead.

7:12

Quite often,

7:14

you won't see any enhancement and you'll just

7:15

have an asymptomatic cord syrinx.

7:17

Now, is this due to a previous traumatic event?

7:20

Is it just a congenital rest that has been

7:23

with the patient all their life?

7:25

Or is it the residual from a previous myelitis?

7:28

Many of these patients are totally asymptomatic,

7:31

so we presume that they are just a congenital cyst,

7:34

similar, if you will,

7:36

to an arachnoid cyst intracranially,

7:38

but obviously within the spinal cord.

7:41

So I mentioned that the cord lipoma was the second

7:49

most bizarre case that I've ever seen.

7:52

This is the number one.

7:54

This is an amazing case.

7:56

Here we have a patient with a T1-weighted

7:59

and a T2-weighted scan, and we have a lesion

8:03

which spans all three spaces.

8:07

You notice that there is a little meniscus here

8:10

posteriorly, identifying this as

8:13

intradural extramedullary.

8:17

You see there is widening of the CSF space,

8:21

identifying this as intradural extramedullary lesion.

8:24

However, when we look at the inferior most portion,

8:28

the lesion clearly is within the spinal

8:32

cord and therefore is intradural intramedullary.

8:37

Except that, in addition,

8:40

there is another component of this same lesion,

8:44

with a cyst, in the extradural compartment.

8:50

So we have all three spaces of the spinal cord and

8:54

the spinal canal that are involved:

8:57

intradural extramedullary,

9:01

intradural intramedullary, and extradural.

9:06

Not only that,

9:07

but this patient also has

9:12

abnormality in the vertebral bodies.

9:16

And you can see that there is a segmentation

9:19

abnormality that there are fused vertebrae.

9:23

In fact, this patient had butterfly vertebrae as well.

9:26

Put it all together. What do you got?

9:29

This is a neuroenteric cyst.

9:32

A neuroenteric cyst is something that occurs in

9:37

association with a segment of the spine where

9:41

there is abnormality in development,

9:44

which is usually the synchondrosis of the sine qua non

9:47

anomaly in the vertebral bodies.

9:49

But you may have intradural extramedullary,

9:53

intradural intramedullary, or extradural components.

9:57

This is the enteric component of the neuroenteric cyst.

10:01

And these parts are the neural component of the

10:06

neurenteric cyst.

10:07

The most bizarre spine case I've ever seen,

10:10

and I wanted to share it with you.

10:13

This is obviously a congenital anomaly.