0:00

Dr. Schupeck,

0:01

this is right up your alley as a neurosurgeon.

0:03

This is a 46-year-old woman who's got low back pain,

0:08

left leg pain following surgery.

0:11

I actually don't have the exact date of her prior surgery,

0:14

but I suspect it's maybe weeks to months,

0:17

but certainly not years.

0:19

And so, relatively recent surgery presumed.

0:23

And on your left, I have proton density fat suppression,

0:26

sees a large person,

0:28

so that makes it a little bit more challenging.

0:31

In the center,

0:31

I have a conventional T2 without fat suppression.

0:36

And that is of interest in terms of the signal

0:39

characteristics of the abnormality.

0:41

And on the right, I have a conventional T1

0:44

without contrast. So as a spine surgeon,

0:50

what do you think? Yeah, what you were saying,

0:53

the history,

0:54

which we have in only a limited fashion is really critical

0:59

for the lumbar disc patient because there's a huge

1:03

difference of somebody who had surgery and never got

1:05

better as opposed to the person who got better was

1:08

great for six weeks and then something happened.

1:11

Okay.

1:12

Because you're going down a whole different

1:14

track because they never got better.

1:16

Maybe they're never going to get better.

1:17

Maybe decompression isn't going to help.

1:18

But if they got better and worse again,

1:21

you got another problem.

1:22

And there's a couple of things it could be.

1:24

Could it be a recurrent extrusion?

1:26

That would be one thing.

1:27

Well, there is something there.

1:28

There is something there,

1:30

but something meaning they were better.

1:33

They had the potential to get better.

1:34

Something happened subsequently.

1:36

So you got to account for that.

1:37

And is it mass effect that is recurrent

1:39

mass effect on the root by something?

1:42

And if there's mass effect on the root

1:44

and they have recurrent symptoms,

1:47

you're going to probably end up re-exploring

1:49

for something, meaning that as imagers.

1:52

We don't want to say we're into like, oh,

1:55

does this enhance?

1:57

If there's mass effect, they were better,

1:59

they got worse again.

2:00

And if the history is something like, hey,

2:01

I was great until I got up, coughed,

2:03

and then pain started going down my leg to my big toe,

2:06

if there's anything to operate on,

2:09

they're going to end up reopening because what else

2:11

are you going to do with the patient now?

2:13

If there's no mass effect,

2:14

then there's nothing to operate on.

2:16

So really that's what we're looking for.

2:18

We're looking for a mass and we have one.

2:19

We do have one. And this is a great teaching point.

2:25

So for those of you that are listening,

2:28

have your coffee right now because here is a gray

2:32

mass on the T1 and then on the T2,

2:35

I think most of you would say the mass,

2:38

I'm going to make it even a little bigger.

2:39

The mass is of intermediate signal intensity character,

2:43

and that would push you in the direction maybe it's

2:46

a little brighter in the center right there,

2:48

but that tends to push you in the direction

2:50

of something more solid,

2:52

less viscous, less fluid-like.

2:56

And we're not going to have a diffusion

2:59

image here to kind of.

3:00

Help us out.

3:01

So if we're looking for something like, say, an abscess,

3:05

we might want to have a diffusion image with a small

3:08

field of view, but that's not at our disposal.

3:10

On the other hand,

3:11

when we go to the proton density fat suppression,

3:14

things are a little brighter.

3:16

But taken another way, I implied, well,

3:21

an abscess shouldn't really be gray, but in fact,

3:24

when you have a pyogenic abscess,

3:26

you get a lot of neutrophils.

3:28

And those neutrophils make peroxidases and

3:31

those peroxidases are paramagnetic,

3:33

so they actually draw down the T2

3:35

relaxivity of an abscess.

3:37

So it's not uncommon on a T2-weighted image not to have

3:42

bright signal intensity on a T2

3:44

spine echo and an abscess.

3:46

And that is a very important pitfall for young

3:48

imagers radiologists neurosurgeons.

3:50

And neurologists don't go down that rabbit hole.

3:55

Now, on a PD, everything's going to be bright.

3:59

So a disc could be bright because acute discs are pretty

4:03

edematous and they can have fluid in them,

4:05

they can have blood in them, they could dissect,

4:07

as you've taught me many times,

4:09

they can wind their way through the posterior longitudinal

4:12

ligament, and it is brighter on the PD,

4:15

but I'm not sure that really helps us tremendously.

4:19

So this would be a case where to try and sort things out,

4:23

I would give contrast because in many postoperative

4:25

backs now, I don't need to give contrast.

4:28

I can tell by the morphology and the signal and

4:31

the history. In this case, not so much.

4:33

I don't have a lot of historical information to help me.

4:36

It's very messy back there.

4:38

I think I'll pull up an axial just to start and then I

4:41

will pull up the C plus study that was

4:45

done in the sagittal projection.

4:46

Let's go right to the area of interest and I'm going

4:48

to make it much bigger for all of you to see.

4:51

And there's quite a bit of tissue there on the left

4:54

side compressing the descending S1 root.

4:56

Now, I can't tell you,

4:58

I don't think any of us could tell on a faceless T1

5:01

whether that's granulation tissue or an abscess or a disc,

5:05

but it's something.

5:06

So your query about is there mass effect?

5:09

The answer is yes. So now let's look at another axial.

5:13

Let's try something that's a bit water-weighted.

5:15

Let's blow it up, make it brighter for everybody to see.

5:18

Let's get on down there.

5:19

And again, it's not particularly bright on the T2.

5:23

It's got this little tent-like appearance.

5:26

There's the apex of the tent,

5:28

there's the base of the tent.

5:30

So I think we're still kind of stuck as

5:33

to what we're really dealing with.

5:35

Now let's go to this axial C plus fat suppression image.

5:40

And as we approach the lesion,

5:42

there's a fair amount of enhancement.

5:45

And I would toodle along, I'd noodle along,

5:48

being pretty comfortable that I'm dealing with

5:51

granulation tissue until I get to here.

5:53

And now my tent. My upside-down tent.

5:56

Or triangle. There's the top of the triangle,

5:59

there's the base of.

6:00

The triangle not enhancing in the middle at all.

6:03

So now I have a problem.

6:05

Now

6:07

this line going right into the disc space,

6:10

is that exactly where that is?

6:11

That is right exactly where that is.

6:13

Right where that line.

6:14

So you almost have sort of a sinus sort of track.

6:16

You do. And so you wonder, okay,

6:19

maybe they went in with one of what's,

6:22

an instrument you'd use there?

6:23

Yeah, well, yeah,

6:25

ron Jurs or punch or Kirschner punches and stuff.

6:28

Oh, wow, that's disc space punches.

6:30

Disc space punches. I like that.

6:31

That's a little simpler for me.

6:33

I'm kind of a meathead.

6:34

So my disc space punch went in there and maybe I created

6:37

that tract and now the nucleus pulposus is coming back out

6:41

that tract. I don't know why you guys do that anyway.

6:44

So maybe it's just a giant extrusion.

6:47

Or on the other hand,

6:48

maybe that's a sinus tract from an abscess.

6:52

Now, will they look alike?

6:53

And the answer is, unfortunately yes,

6:56

they will look alike. I mean,

6:58

what are the characteristics of an

6:59

abscess anywhere in the body?

7:02

Well, anywhere in the body you're going to get a cavity.

7:06

And that cavity is going to have a lining.

7:08

And unlike a tumor,

7:10

that lining is going to be pretty thin.

7:12

In fact, I'm going to make my line even thinner.

7:14

It's going to be pretty thin around the outside.

7:18

And then if you're in a place where you can get

7:21

tissue reaction around it, like the brain,

7:24

you are actually going to have a

7:27

fibrotic reaction around that.

7:29

So you'll have an enhancing rim around this capsule here

7:35

and then you'll have a fibrotic rim around

7:37

that if you were in the brain.

7:39

And then around that, you'll have some Edema.

7:43

You'll have a fair amount of Edema.

7:44

Now we're not in the brain,

7:45

so we're not going to get the benefit of the Edema.

7:47

But we sure have a lot of enhancing tissue around it,

7:50

above it, and below it.

7:53

So let's put up the Sagittal C plus fat suppression image.

7:58

And there is a finding that I have found very useful in

8:03

differentiating a disc from an abscess because

8:07

they're both going to be cold in the middle.

8:09

So let me make them about the same size.

8:12

So it's nice and pretty.

8:15

And that finding is what I call crinkling.

8:20

Now a disc,

8:21

I like to see my discs look kind of like a mushroom.

8:25

Let me draw properly.

8:26

I like to see them do something like this.

8:29

And I like to see them pretty firm.

8:32

Discs, for the most part, are pretty tough material.

8:36

Even nucleus pulposus material under pressure and swollen

8:42

is pretty tough. So it may look like this,

8:44

it may even kind of go up and down a little bit from the

8:47

disc space, but it shouldn't have this sort of wavy,

8:50

almost Casper the Friendly Ghost look before

8:54

it goes back into the disc space.

8:56

And this is doing that so that combined.

8:59

With all the inflammation, combined with the history of,

9:03

as you said, just horrendous back pain,

9:06

which these patients get, I think,

9:08

points to the diagnosis,

9:10

which is proven of a disc space abscess.

9:13

I have one other really important comment,

9:15

but I want to hear your thoughts

9:17

on this. Yeah, I think that to me,

9:22

the key is if the patient's got mass effect and recurrent

9:24

particular symptoms, they're going to have an operation.

9:27

Now, the surgeon it's very great if you can say, oh,

9:31

I might be running into an abscess here,

9:33

you might do some things differently.

9:34

But the key is really the patient needs an operation.

9:38

You may not be able to make that distinction,

9:39

but you can certainly alert to that possibility.

9:42

Hey, this might not be a giant recurrence.

9:44

And also

9:47

all of this,

9:48

it's kind of messy for a big recurrent extrusion,

9:52

meaning there's definitely an inflammatory-looking,

9:55

I would say, component to all of that.

9:57

Let me ask you a question.

9:58

Would you be angry with me if I called it a recurrent disc

10:01

and you went out and went in and found it was an abscess?

10:04

And would it change the management of the case,

10:06

or would it change your surgical approach to the case?

10:08

It really wouldn't. The approach is similar.

10:12

That basically the recurrent disc.

10:14

What you do is you find the border of

10:16

your previous laminectomy, okay?

10:18

And then you work your way down to the floor of the

10:21

canal because you don't know where the root is.

10:23

It's all in scar. So you go down to where you know,

10:26

get down to the floor, and then you work your way in.

10:29

You're going to take the same approach.

10:31

Is this where you go?

10:32

Right. You kind of find this border.

10:35

I'd work my way right here down until I was a disc and

10:39

then go this because I know that the root is medial.

10:41

I mean,

10:41

the thing you don't want to do is run into the root.

10:44

So you go like you don't want to start fishing around and

10:46

all this stuff. You want to be pushing everything medial.

10:49

Okay?

10:50

And so you would take the same approach right on this

10:52

bony edge, get to what's left of the disc space,

10:57

identify that on the floor of the canal,

10:59

start working your way in,

11:00

and push all that stuff from the last operation medial,

11:03

including the root. You push this, all this.

11:06

That's right.

11:07

Take the same approach. Sorry.

11:09

Would it matter to you how much of this bone remains?

11:13

Is that critical in the description by the radiologist?

11:16

In other words, did they take down the facet?

11:18

Did they not take down the facet?

11:19

Because a lot of people use the term they throw

11:22

the term laminectomy around all the time.

11:24

You've got micro laminotomies, laminotomies,

11:26

laminectomies. Does that matter to you?

11:28

Well, yeah, theoretically,

11:31

you want to preserve the facet if you can.

11:33

Okay. On the other hand,

11:35

I can tell you I was trained in an era back in the Mayo

11:37

Clinic. The operations were much more extensive,

11:40

and a lot of people did just fine with it.

11:42

So I would say that describing how much is left.

11:45

Meaning if there's a total facetectomy yes,

11:47

because that means you're looking for a different anatomy.

11:50

You're going to get in on that inferior articular surface.

11:53

Okay. So you're looking for that.

11:55

So describing the bony anatomy and what's there

11:58

is very important. And if they have.

11:59

Total facetectomy.

12:01

But

12:02

the fact is, you got to do what you need to do.

12:05

Sure. So you got to get here.

12:08

You want to take as little bone as possible.

12:10

Meaning I might not even take bone.

12:11

I might just take a curette,

12:13

get in that plane and work right along

12:15

the face of that facet on my way down.

12:18

But we might take a little bit of bone.

12:21

Now,

12:21

I don't want to insult my neurosurgical

12:23

colleagues that are out there,

12:24

because I know you all look at your own MRI,

12:26

so you're going to know how much bone is gone where

12:29

I think it'll be a little more challenging

12:31

for you neurosurgeons is, what is this?

12:34

Is it an abscess or is it a disc?

12:36

And that crinkle sign is really reliable.

12:39

And also the fact that you see that rim enhancement that's

12:42

so consistent all the way around in terms of thickness,

12:45

like all abscesses throughout the body.

12:48

And there's one other point I want to

12:49

make that's helped me so many times.

12:52

It's saved me, and it's helped me save some people.

12:56

When you think about a surgeon going in with their

12:59

instruments whose names I won't repeat,

13:03

you think, well, okay,

13:05

you're rubbing a piece of metal in the disc space,

13:07

you should get some edema right next to it.

13:10

But but the fact of the matter is you don't.

13:13

So when I have somebody with back pain,

13:15

with intractable back pain,

13:17

especially if it's not sudden onset like,

13:19

you would expect a disc.

13:20

And I start to see this ill-defined laminar signal riding

13:25

right along the cortex and subcortical bone adjacent

13:30

to where this abnormality is coming out of.

13:34

I am very suspicious, even if I don't have a mass,

13:37

I am very suspicious of postoperative discitis,

13:40

especially when the pain is disproportionate

13:43

and I read it.

13:44

And I often will make or insist that those individuals go

13:49

on for either a workup or get my preference empirical

13:52

antibiotic therapy. So this sign is a very useful sign,

13:56

and especially if you see it on a T1,

13:58

it's even more specific. This laminar low signal on T1,

14:02

I don't have one right here,

14:03

but I do have the fat suppression and T1 with contrast.

14:06

And you can even see it on the PD right there

14:09

that should not be there after surgery.

14:11

And it goes pretty far forward.

14:13

That is a soft but very important sign of postoperative

14:18

discitis. And this is one with an abscess.

14:20

Let's move on, shall we?