0:00

Let's start out with this 75-year-old man who's got

0:03

right hip pain. He's had a right hip arthroplasty.

0:08

And we've got before you a sagittal proton

0:11

density fat suppression, water-weighted,

0:13

a T1 fat-weighted in the middle,

0:15

and a T2 spin echo on the right,

0:19

with little in the way of fat suppression.

0:22

So let's scroll a little bit just

0:23

so you can get your bearings.

0:25

And I'm sure you've all dialed into the bright

0:28

disk space at what we'll call L3-4.

0:32

It's bright on the T2 and the PD.

0:35

And then we'll give you a second to

0:36

kind of gander at everything else,

0:38

showing you only sagittals to start with.

0:41

Now, besides this area of hyperintensity

0:45

at what we'll call L3-4,

0:48

and we'll discuss its posterior extent in a minute.

0:52

I'm here with my colleague,

0:54

neuroradiologist and partner, Dr. Ben Lazar.

0:58

Dr. Lazar, what do you think of this area above

1:01

the disc space abnormality?

1:03

So, given the hyperintensity within the disc,

1:08

the signal above is bulbous.

1:11

It's fat-like. It could either be post-surgical,

1:15

given the appearance of surgery,

1:17

or it could be a dilated venous structure,

1:20

possibly correlating with the patient's symptoms.

1:23

Sure. And it doesn't really look like a cavity.

1:26

Right? So it's probably not an abscess,

1:28

even though that would be a consideration,

1:30

at least emotionally,

1:31

because you have this bright signal below.

1:33

And one of the things you'd wonder about is,

1:36

does this patient have discitis?

1:37

Because the disc is so bright.

1:39

But one thing mitigating heavily against discitis.

3:11

And sometimes the nerve roots will even glue

3:11

And sometimes the nerve roots will even glue

3:13

around the periphery, like we see here.

3:13

around the periphery, like we see here.

3:13

around the periphery, like we see here.

3:16

That's just one nerve root sitting by itself.

3:16

That's just one nerve root sitting by itself.

3:16

That's just one nerve root sitting by itself.

3:18

The rest of them are stuck to the edge of the dural

3:18

The rest of them are stuck to the edge of the dural

3:18

The rest of them are stuck to the edge of the dural

3:21

sac. We can see that over here as well.

3:21

sac. We can see that over here as well.

3:21

sac. We can see that over here as well.

3:23

And this is an operated level.

3:23

And this is an operated level.

3:23

And this is an operated level.

3:25

So the patient demonstrates innumerable signs of

3:25

So the patient demonstrates innumerable signs of

3:25

So the patient demonstrates innumerable signs of

3:29

arachnoiditis, which, if I draw them out, you'd say,

3:29

arachnoiditis, which, if I draw them out, you'd say,

3:29

arachnoiditis, which, if I draw them out, you'd say,

3:32

okay, thick periphery of the dural sac,

3:32

okay, thick periphery of the dural sac,

3:32

okay, thick periphery of the dural sac,

3:34

which this patient has on the T1.

3:34

which this patient has on the T1.

3:34

which this patient has on the T1.

3:37

Another sign would be there's no roots inside.

3:37

Another sign would be there's no roots inside.

3:37

Another sign would be there's no roots inside.

3:41

So completely blank in the middle.

3:41

So completely blank in the middle.

3:41

So completely blank in the middle.

3:43

Okay, there's one root here.

3:43

Okay, there's one root here.

3:43

Okay, there's one root here.

3:44

So the empty sac sign that you alluded to.

3:44

So the empty sac sign that you alluded to.

3:44

So the empty sac sign that you alluded to.

3:47

And then one I haven't shown here because

3:47

And then one I haven't shown here because

3:47

And then one I haven't shown here because

3:50

this patient doesn't have it,

3:50

this patient doesn't have it,

3:50

this patient doesn't have it,

3:51

but it's kind of a cool sign,

3:51

but it's kind of a cool sign,

3:51

but it's kind of a cool sign,

3:52

and it can be very confusing.

3:52

and it can be very confusing.

3:52

and it can be very confusing.

3:54

So let's make this the dura.

3:54

So let's make this the dura.

3:54

So let's make this the dura.

3:56

And then inside the dura,

3:56

And then inside the dura,

3:56

And then inside the dura,

3:58

you get something that looks like a cord,

3:58

you get something that looks like a cord,

3:58

you get something that looks like a cord,

4:01

except you're down at around L4.

4:01

except you're down at around L4.

4:01

except you're down at around L4.

4:03

And there is no cord at L4 unless

4:03

And there is no cord at L4 unless

4:03

And there is no cord at L4 unless

4:05

you have a tethered cord.

4:05

you have a tethered cord.

4:05

you have a tethered cord.

4:06

And that's just roots that are clumped together that

4:06

And that's just roots that are clumped together that

4:06

And that's just roots that are clumped together that

4:09

masquerade as a cord. So the pseudocord sign,

4:09

masquerade as a cord. So the pseudocord sign,

4:09

masquerade as a cord. So the pseudocord sign,

4:13

another sign of arachnoiditis.

4:13

another sign of arachnoiditis.

4:13

another sign of arachnoiditis.

4:16

That probably isn't the main thrust of the case.

4:16

That probably isn't the main thrust of the case.

4:16

That probably isn't the main thrust of the case.

4:19

I mean,

4:19

I mean,

4:19

I mean,

4:19

I think together we give everybody

4:19

I think together we give everybody

4:19

I think together we give everybody

4:21

all the facet disease.

4:21

all the facet disease.

4:21

all the facet disease.

4:22

There's a tremendous amount of postoperative change,

4:22

There's a tremendous amount of postoperative change,

4:22

There's a tremendous amount of postoperative change,

4:25

and we don't want to lull people to sleep

4:25

and we don't want to lull people to sleep

4:25

and we don't want to lull people to sleep

4:27

with all those other findings.

4:27

with all those other findings.

4:27

with all those other findings.

4:28

There's spondylosis at multiple levels.

4:28

There's spondylosis at multiple levels.

4:28

There's spondylosis at multiple levels.

4:31

So let's go right to the heart of the matter,

4:31

So let's go right to the heart of the matter,

4:31

So let's go right to the heart of the matter,

4:33

which is the L34 level, or what we'll call L34.

4:33

which is the L34 level, or what we'll call L34.

4:33

which is the L34 level, or what we'll call L34.

4:38

And what do you think is going on here?

4:38

And what do you think is going on here?

4:38

And what do you think is going on here?

4:41

So, at that point,

4:41

So, at that point,

4:41

So, at that point,

4:43

the patient's post partial laminectomy.

4:43

the patient's post partial laminectomy.81 00:03:11,065 --> 00:03:13,618 And sometimes the nerve roots will even glue

4:43

the patient's post partial laminectomy.

4:45

At this level, it looks like there's fluid,

4:47

actually CSF signal intensity fluid tracking

4:51

into the facet joint number one,

4:53

and number two tracking towards the intervertebral

4:56

disc space right at the level of the surgery.

4:59

Yeah.

5:00

And the fact that it goes into the

5:02

disc space is a little unnerving,

5:05

because if you're thinking about maybe a CSF leak,

5:08

you'd like it not to go directly

5:11

into the disc space.

5:12

That kind of makes you think more about maybe

5:13

nuclear material coming out or infection coming out,

5:17

but it really doesn't look destructive enough

5:21

or messy enough for it to be an infection.

5:24

And we've already said it's virtually impossible.

5:27

This is a really good sign.

5:29

It's virtually impossible to have a PD spur,

5:32

to have an abscess, to have a disc space abscess,

5:35

and have normal end plates and

5:37

normal vertebral signal.

5:38

So we can pretty much throw that one out

5:43

as we look at the axial projection.

5:44

And I'm going to blow this one up bigger.

5:47

There are a couple of signs in here

5:49

that I think are really helpful,

5:51

but let's talk about fluid collections that occur in

5:55

the postoperative situation

5:57

the typical one would be.

5:59

Seroma and usually you get big seromas in the

6:03

back and they do not dissect into the,

6:06

thecal sac very often they kind of sit back here,

6:09

maybe they go in a little bit.

6:10

This way they're not under a lot of mass

6:13

effect even though they're pretty big,

6:15

they don't press things away

6:19

with any great urgency.

6:21

The other thing seromas do not do is,

6:25

is they kind of don't go around the front.

6:27

And this I found to be a very valuable sign.

6:31

They don't go around the anterior margin of the

6:35

thecal sac. We've already talked about abscess.

6:38

We've set that one aside.

6:41

Dural leak,

6:42

that's a pretty important one and that's one

6:44

that we'd absolutely want to exclude here.

6:48

So what are the types of things clinically that

6:51

would make you think about a Dural leak?

6:53

So clinically, what do they get?

6:55

They get headaches typically from cerebral

6:58

hypotension, depending on where the leak is,

7:02

where the leak is going,

7:04

and then typically,

7:06

depending on where the leak is,

7:08

they would have signs and symptoms of lower

7:10

extremity radiculopathy. Well, yeah,

7:12

if there's mass effect,

7:13

if it's under pressure and it hits the root and

7:16

maybe it is hitting the descending l four root

7:18

right here, they would get radiculopathy.

7:21

And their headaches are very typical, right?

7:23

They get orthostatic headaches.

7:25

So when they're lying down they feel fine.

7:28

When they stand up they are just

7:30

absolutely totally miserable.

7:32

In some cases it almost looks like they have cancer.

7:35

They're drawn, they can't eat, they're nauseous,

7:37

they've lost weight.

7:39

It is really a very contentious problem as opposed

7:44

to say somebody that has increased intracranial

7:47

pressure where they're lying down and

7:50

they vomit early in the morning,

7:52

somebody that has hypotension,

7:56

they feel fine when they're lying down.

7:57

When they wake up,

7:58

they feel their best when they wake up and then as

8:01

soon as they start to stand up and walk

8:03

around they feel absolutely awful.

8:06

Another aspect of a Dural leak,

8:09

which we cannot demonstrate here is dural leaks have

8:13

very little enhancement whereas abscesses have

8:15

smooth, pretty thin enhancement around them.

8:20

Another feature of a Dural leak which is demonstrated

8:24

here and I'm going to blow it up even bigger.

8:26

Now we'll go into the ten x microscopic mode and so

8:31

here's our thecal sac and this time you can actually

8:35

see the communication with the thecal sac.

8:37

So this one's kind of weird because it's

8:40

communicating with the thecal sac and it's

8:42

communicating with where they directed

8:45

their curette into the disc space.

8:47

So that's a little bit confusing.

8:49

But once you see this attachment here

8:52

or this communication, you know.

8:54

Now another sign of a dural leak is if you see

8:57

nerve roots that are prolapsing towards.

8:59

The hole. And that is happening here, right?

9:02

Because you're getting fluid that's coming out.

9:04

So the nerve roots are prolapsing towards the hole.

9:07

Another very important sign of a dural leak.

9:12

Now,

9:12

another consideration would be a hemorrhage

9:15

as far as a fluid collection.

9:17

And what do we think of that as a consideration?

9:20

Let's blow up our T1 and get right to the same level.

9:24

And we liken hemorrhage as a possibility, right?

9:27

Because they've been curating and

9:28

rongeuring around in there.

9:30

Would we consider that in this case?

9:33

I would not.

9:34

There's no hyperintense T One signal

9:37

and just correlating with the T Two imaging.

9:41

Yeah. I mean, there's no contiguous yeah.

9:44

There's no deoxyhemoglobin T2 shortening.

9:47

There's no methemoglobin staining.

9:50

In other words,

9:51

there's nothing to suggest visually that

9:54

there's hemorrhage inside it. Now,

9:56

sometimes in a hyperacute hemorrhage,

9:58

it's going to look like proteinaceous fluid,

10:01

like 1-hour-old, two-hour-old hemorrhage.

10:03

And you will see that because if you

10:05

have a hyperacute hemorrhage,

10:07

it's going to compress the cord.

10:08

They come right in because they're paralyzed.

10:10

But that's not the case here.

10:13

This has been going on for a while,

10:15

and that is indeed a very rare event.

10:17

So unless it's hyperacute,

10:18

it's not going to look anything like this at all.

10:21

This looks like CSF. So in summary,

10:24

it's communicating with the thecal sac number one.

10:27

Number two,

10:28

it's got a nerve root that's going out through the

10:31

hole. Number three, it's anterior to the thecal sac,

10:36

number four,

10:37

it isn't in the usual place where you have seroma.

10:39

And we've pretty much excluded for reasons we

10:42

discussed, abscess and a hematoma and a seroma.

10:47

So we've excluded the lookalikes.

10:49

And then we also said that patients with this

10:52

syndrome are going to have headaches,

10:54

bad headaches and orthostatic hypotension.

10:57

Now, there's one other caveat.

10:59

If it's there long enough,

11:01

it's not demonstrated in this case because the

11:05

pressure is low, the epidural veins will dilate.

11:08

And I think you mentioned to me you wondered if

11:09

that might not be a big, weird epidural vein.

11:13

That's a possibility.

11:15

But when those epidural veins dilate,

11:17

you're also going to see enhancement of the

11:20

meninges or pachymeninges in the spine.

11:23

So those are two other ancillary

11:25

supportive signs of a dural leak,

11:28

and sometimes it may be worthwhile going up into the

11:31

brain and seeing how much pachymeningeal enhancement

11:33

they get up top. Let's move on to another case, shall we?