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Hello and welcome to Noon Conference, hosted by Modality

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and previous noon conferences by creating a free account.

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Today we are honored to welcome Dr.

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Steven Pomerance for a lecture entitled, practical Aspects

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of Spine Imaging and Reporting.

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Dr. Pomerance is the CEO

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and Medical Director of ProScan Imaging

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and the founder of MRI online.

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He's authored numerous medical textbooks

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and MRI, including the MRI, total Body Atlas.

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He's also an AVID conference, lecturer

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and chairs, the fellowship training program and MR.

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And Advanced Imaging.

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At the end of the lecture, please join him in a q

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and a session where he will address questions you

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may have on today's topic.

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Please remember to use that q

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and a feature to submit your questions so we can get to

0:58

as many as we can before time is up.

1:00

With that, we're ready to begin today's lecture. Dr.

1:03

Pomerance, please take it from here.

1:06

All right, welcome everybody.

1:09

We're gonna talk about, uh, disc disease.

1:12

We're gonna focus on lumbar disc disease,

1:14

but we are gonna show you some cases in the cervical

1:16

region as well.

1:19

And we're gonna focus on terminology

1:23

and how to describe things

1:24

and some nuanced aspects of spine reporting.

1:28

And I will warn you ahead of time

1:30

that this is a pretty dense talk if you haven't been doing,

1:33

uh, spine, Mr.

1:35

So we're gonna start out with the normal, uh,

1:37

lumbar disc anatomy in the axial projection.

1:40

The periphery of the disc is made up of dense, fibrous

1:43

and collagenous tissue called the annulus,

1:45

and in the middle is the gelatinous nucleus.

1:48

And it looks something like this in the sagal projection.

1:51

It looks a little bit like an eye,

1:53

especially on a water weighted image.

1:55

The same thing will be seen in the coronal

1:58

projection, a a as well.

2:01

And um, the, the size of the nucleus pulposus relative

2:05

to the analyst fibrosis is pretty consistent,

2:08

but there is some variation from person to person.

2:12

The disc should stay within the confines of the cortex

2:17

on either side, uh, both posteriorly

2:20

and anteriorly in the sagittal projection.

2:22

And the same thing is true in the coronal projection.

2:26

So here is some normal anatomy at 1.5

2:29

and three T Here is your disc space,

2:32

and these are T one fat weighted images.

2:34

You can't really discriminate the nucleus from the annulus

2:37

on T one imaging.

2:39

And there, there are some salient aspects of anatomy here,

2:43

including the Bai vertebral plexus in the middle

2:45

of the vertebral body, which will

2:47

become relevant a little bit later.

2:49

And then the osteochondral endplate, which is dark.

2:53

And some of you may be wondering why the endplate

2:56

beneath is white.

2:57

And that has to do with an artifact called chemical shift

3:00

artifact, which is a little bit beyond the scope

3:03

of our discussion today.

3:05

But the integrity of the nplate will be very important in

3:08

deciding whether there is destruction of it from infection,

3:11

which we're not gonna talk about today,

3:13

versus inflammatory change from instability.

3:17

Now, all of the discs line up with the cortex, the only one

3:21

that doesn't line up with the cortex normally.

3:23

I'm not saying this one is normal,

3:25

but you're gonna get a little bit of protrusion

3:27

or bulging down at L five S one

3:29

'cause that is bearing the weight.

3:31

And there's an angle change there.

3:32

So I like to see my disc space space is flat

3:36

or convex forward except for L five S one.

3:40

So I'm gonna ignore L five S one right now.

3:42

And I, I'm just gonna select one of these discs,

3:44

the L two three disc.

3:46

And here is your, your sort of closed eye,

3:50

that's the nucleus osis.

3:51

It's a little bit brighter,

3:53

and then the annulus is gonna be on the periphery,

3:55

and that's gonna be true circumferentially.

3:57

As you go out to the side,

3:59

you know you're gonna volume average annulus.

4:02

You know, some of the terms we're gonna cover today are

4:05

bulge, protrusion, extrusion free fragment migration.

4:08

We'll talk about dis space height, desiccation the size

4:11

of a herniation, and the zone to which it goes.

4:14

And that is not all.

4:17

Now in the lumbar spine,

4:19

because there's a lot less pulsation, it's much easier

4:22

to get uniform cerebral spinal fluid conversion

4:26

as you go up the spine into the thoracic

4:28

and especially the cervical region,

4:30

there is more bounding pulsation.

4:33

So there'll be instances where your,

4:35

your water weighted images are not as homogeneous.

4:38

And this can produce some degree of confusion.

4:42

The sagittal view is, is a helpful view to look at the size

4:45

of the spinal canal.

4:48

Uh, but when you're assessing stenosis,

4:50

the axial is probably the gold standard.

4:52

And here's an example of a sagittal

4:56

in which the spinal canal is severely,

4:58

severely an narrow at every single level.

5:00

And you know this, by seeing the compression of the cord

5:03

and conus, you're also seeing,

5:05

seeing something called osteochondrosis with small nodes,

5:09

uh, at every single level,

5:10

which we will delve into in some depth.

5:13

So this patient has some type of generalized abnormality,

5:17

which in this 33-year-old is a connective

5:19

tissue abnormality.

5:21

Uh, these osteo chondro abnormalities went all the way up

5:24

and down, but I'm showing it for the, the bulges

5:27

and the short pedicles

5:28

that have encroached on the neural tissue,

5:31

which is very obvious.

5:32

If you go back to the, the normal

5:34

and then scroll back to the abnormal,

5:37

you see a huge difference in the size of the canal

5:39

and loss of the anterior cerebral spinal fluid,

5:42

which is white here, here, here, and so on down the line.

5:48

Now, in the axial projection, uh, we, we go back and forth.

5:52

We toggle back and forth between sagittal and axial

5:55

and use some reference lines to, to help us.

5:58

But the axial projection is a little bit easier in telling

6:00

where disc abnormalities might exist in the midline.

6:05

We call them central disc herniations.

6:08

Um, and then off to the side, we call them subarticular, uh,

6:12

disc herniations.

6:13

If it's slightly off to one side

6:15

or the other, not perfectly in the mi midline,

6:18

I might use a term that I,

6:19

that I coined years ago called paracentral.

6:21

So I might say left paracentral,

6:23

right paracentral or central.

6:25

Then we get into subarticular recess, then the,

6:28

the proximal foramen

6:29

and the distal foramen, also known

6:30

as the extra foraminal space here in yellow.

6:34

So that's some basic zonal description.

6:38

So here's another a little less basic zonal description.

6:42

The top is an axial projection.

6:44

The bottom is a coronal projection.

6:46

And here we see our central, our central area.

6:49

This is our subarticular zone, slightly off

6:51

to the side as we described.

6:53

Then we have the foraminal zone, some people refer to

6:56

as the proximal foramen.

6:58

Then we have the extra foraminal zone.

7:00

Some people refer to it as the distal foramen.

7:02

And for those of you that are very OCD,

7:05

you might even go proximal mid and peripheral foramen.

7:09

So some people break the foramen down into

7:12

three separate zones.

7:13

That might be a little bit extreme.

7:15

I happen to be one of the people that do that,

7:17

even though I'm not, I'm not very OCD.

7:19

So let's talk about the nerve roots in the lumbar spine,

7:23

the nerve roots are gonna descend

7:25

and the cervical spine, they come more out to the side.

7:29

I'm gonna demonstrate that in a moment.

7:31

And the reason that's important if is if you're at the L two

7:35

three level, when you look at the nerve root,

7:40

that's exiting the foramen, it is going to be L two.

7:44

If you're at the C two three level for a number

7:48

of anatomic reasons,

7:49

the exiting route at C two three will not be C two,

7:53

it will be C3.

7:55

So this is a very important distinction

7:57

and here's one of the reasons you can see why the cervical

8:00

roots are more horizontally oriented.

8:02

So you don't get descending compression

8:05

of recess roots in the cervical region like you do in the

8:09

lumbar region, where the descent is a little

8:12

more vertically oriented.

8:14

So at C four five, the roots coming out here is going to be

8:18

C five, whereas if you are in the lumbar spine

8:22

because of the the descent, the oblique course of descent,

8:26

um, if you're at L three four, it is the L three,

8:30

not the L four root that is coming out at that level.

8:32

That is a very important

8:34

and significant difference when you're learning spine.

8:38

So we're getting a little deeper into

8:40

zones and descriptors now.

8:41

And um, one thing I find easiest is to go back

8:45

and forth between the sagittal and not shown the axial,

8:48

but I am showing the Corona for purposes of education.

8:51

And at this level you're at the pedicle level.

8:54

So pretty easy above that is the super particular level.

8:59

Below that is the infra particular level right down,

9:02

down here, and then the disc space level.

9:05

And some individuals will use those descriptors,

9:08

super particular, particular and infra particular

9:11

or disc space level by combining and toggling back

9:15

and forth between the axial and sagittal.

9:18

Sometimes you can include your coronal scout

9:20

to help you along with, with those issues.

9:24

Let's talk about a phenomenon

9:26

that occurs in the meniscus of the knee.

9:28

Even though we're not talking about the knee,

9:30

we're talking about a collagenous fibrous structure.

9:34

The annulus fibrosis, it can have a tear,

9:37

like a meniscus tear

9:38

and like a meniscus tear of the of, of the knee.

9:41

They can be completely horizontal.

9:43

These are called cleavage type tears.

9:44

They're usually chronic, they're usually degenerative.

9:46

They're less commonly symptomatic.

9:49

Then you get something called a circumferential tear.

9:52

A circumferential tear is just what it sounds like.

9:55

It is a tear that that follows the course

9:57

of the peripheral annulus.

9:59

I think my pen is not working today

10:01

and I'll, I'll show that to you here in a moment.

10:04

And then we have the radial tear,

10:06

which is a complex deep tear usually associated

10:09

with extrusions, and these are often very symptomatic.

10:13

So here's a diagram showing you the disc space

10:17

and the transverse tear is exactly as it sounds.

10:20

Lemme take one more try at my,

10:23

my pointer, which was working before.

10:25

Okay, we'll have to go without the,

10:28

without the drawing tool.

10:30

So the, the transverse tears are gonna be horizontal,

10:33

just like horizontal meniscus tears.

10:36

The circumferential tears labeled C are gonna follow the

10:40

peripheral course of the annulus.

10:41

These may or may not be symptomatic, but usually not.

10:44

It's the radial tears that are vertical radially oriented,

10:48

just like the radial tears in the meniscus of the knee.

10:51

And they often go from the nucleus to the annulus

10:54

and then material will spit out the hole of the radial tear.

10:58

So those are the three types, radial,

11:00

transverse, and concentric.

11:04

So here's an example of a radial tear.

11:09

Yes, pay no attention

11:10

to the abnormal displacements at L three four

11:13

and L four five, but look at L three four.

11:16

There is a small peripheral radial tear.

11:19

Now you would need the aio to decide if it is a

11:22

concentric tear C or if it's a transverse tear T

11:27

but I'm not sure it really matters that much.

11:29

But one thing we can say is it's not a radial tear

11:32

'cause radial tears are deep, they're complex,

11:35

they head in towards the annulus fibrosis.

11:39

And here is an axial projection, and you see this very broad

11:44

but focal abnormality.

11:46

This is a protrusion type herniation.

11:49

And we're volume averaging the very bottom of

11:51

that protrusion type herniation terminology coming up in a

11:54

few moments, but I'm showing it

11:56

for the annular tear this time.

11:58

You can see the annular tear is following a course

12:01

that is analogous to the peripheral course of the annular.

12:04

So this is a very small concentric type, not

12:07

that it matters concentric type annular tear.

12:11

Okay, now let's get into the terminology of the family

12:15

of disc displacement.

12:20

And the upper left hand corner is a,

12:22

is a normal axial view of the disc.

12:25

The periphery of the annulus corresponds to the free edge

12:29

of the vertible body, including the cortex, which by the way

12:32

can be very hard to see because remember, CSF is dark

12:36

and the cortex is dark.

12:38

So they may blend together

12:40

and your eye may just subtract out the cortex,

12:43

making it into a challenging situation

12:46

where you may over call soft disc disease when it really is

12:49

covered by bone.

12:52

Here's an example of a disc bulge.

12:53

Now the disc has conically gone beyond the free edge

12:58

of the cortex, which are these dotted lines.

13:01

And concentric means 360 degrees,

13:03

but by strict criteria it's 180 degrees.

13:06

The back, 180 degrees is all you need for a bulge.

13:11

Now some of my colleagues have used the term

13:15

asymmetric bulge.

13:16

I resisted this for years and years

13:20

because it's kind of like being sterly pregnant.

13:22

They don't go together. You know,

13:24

a bulge should be concentric.

13:25

So you're saying it's concentric eccentric.

13:28

But I finally have given in And um,

13:31

below you see something called an an asymmetric dis bulge,

13:35

which by the way is often associated with curvatures

13:38

of the spine with, uh, thoraco lumbar, uh, scoliosis.

13:42

And here the annular tissue extends beyond the edges of the,

13:45

of the vertebral, uh, apophysis,

13:48

and it's asymmetrically greater than 25% of the disc.

13:53

So 25% would be 25% of 360 degrees.

13:57

So this is a phenomenon that,

13:59

that I have now adopted against my will.

14:02

And, um, you should be aware of that terminology,

14:04

which can be a little confusing to, to some clinicians.

14:09

Now let's talk about herniated discs.

14:12

First, the protrusion type of herniated disc.

14:16

When you're, when you're into a herniated disc,

14:17

you're into ality.

14:19

It has a tip to it.

14:21

Now, the typical teaching is

14:23

that these are smaller than extrusion type herniations.

14:27

Uh, they involve less than 25%

14:30

of the width of the disc base.

14:33

And again, they're not, they're not very big.

14:35

They're broad based,

14:37

and the base is always wider than the apex.

14:40

This works well for protrusions,

14:43

but we'll see that it doesn't work as well for extrusions.

14:46

And I'll explain that in a moment.

14:48

So a protrusion is covered by annulus. It's not very big.

14:53

It's broader at the base than it is at the apex

14:56

and involves less than 25%

14:58

of the circumference of the disc space.

15:01

Now do I measure that? Of course I don't.

15:04

That would drive me absolutely mad.

15:06

And here in the sagittal projection,

15:08

you can see the protrusion type herniation marginated

15:11

by the peripheral annulus fibrosis,

15:15

the extrusion type of herniation.

15:18

In the extrusion type of herniation, the annulus is broken,

15:22

the nuclear material has dissected through.

15:26

So because there's nuclear material, which tends

15:29

to be brighter, extrusions are going

15:33

to be brighter on heavily water weighted images

15:36

than protrusions.

15:37

So another criteria

15:38

for a protrusion type herniation is it's not too bright

15:41

unless there's a preexisting annular tear.

15:45

Extrusions are said to be polypoid.

15:48

They can make it like a tongue

15:50

hanging down out of your mouth.

15:53

And they are said to have a narrower base and a

15:56

and a bigger apex.

15:58

Now this is an unreliable sign,

16:00

even though it is proselytized throughout

16:02

the radiology world.

16:03

And the reason is you have a ligament here called the

16:07

posterior longitudinal ligament.

16:09

That ligament can squish the disc forward.

16:12

So I don't put as much stock in this criteria

16:15

of base being narrower than apex as I do with size,

16:20

with signal, with position, with the ability

16:24

to see a communication with the nucleus pulposus.

16:27

I use those far more reliably than this base to apex,

16:32

uh, consideration.

16:35

So I hope that makes sense to all of you.

16:37

And I know that goes against the strict rules,

16:40

but if you're too OCD, there are always exceptions to rules

16:43

and that happens to be a very common exception.

16:47

The next stage of, uh,

16:49

herniated discs is the ones that break off.

16:52

These are easy, these are known as sequestered discs

16:55

or free fragments.

16:56

They lose all connection,

16:57

but it's not uncommon, even though the connection is lost

17:00

for this to butt right up against the tear right there.

17:04

So you have to look very carefully

17:06

and sometimes magnify to identify

17:08

that you truly have a free frag.

17:11

So here's an exa, an example of a disc herniation.

17:14

There's a little bit of listhesis.

17:15

This is a T two weighted image.

17:16

This is a fat weighted T one weighted image.

17:19

It's a little bit fuzzy and I show this case intentionally.

17:23

Is it a protrusion type herniation

17:25

or an extrusion type herniation?

17:26

I don't think you know yet,

17:28

but the fact that it's going north by northwest,

17:31

it's going up, suggests that it's an extrusion.

17:35

But now let's look at the axial projection

17:38

and the axial projection.

17:39

The patient has a real problem, big facets, mashed clumped,

17:44

compressed fecal sac,

17:46

and on the right hand side, the T two weighted image,

17:48

you see no cerebral spinal fluid.

17:50

Now you have to really look hard

17:52

and squint to see the, the abnormality.

17:55

It's right here. It's right there. That's tough.

18:00

However, the, the mere size of it, the width of it,

18:04

and it, it, it doesn't have a narrow base,

18:06

it has a very broad base and that's

18:09

because it is squished forward,

18:11

even though it is a polypoid,

18:13

it was originally a polypoid lesion.

18:15

It's squished forward by the leg flava by, by the facets

18:19

and by the posterior longitudinal ligament.

18:22

And this patient has really serious canal stenosis

18:26

and may have neurogenic claudication.

18:30

Let's take a look at another example of a disc herniation.

18:34

Um, above at L two three,

18:36

we have a protrusion type herniation.

18:38

How do I know I've got the axio, but also it's pretty small.

18:42

It doesn't really migrate very far.

18:44

It as an annular tear associated with it,

18:47

but I'm showing it for this one.

18:49

So you have a protrusion type

18:50

herniation with an annular tear.

18:52

Then you have one that's a little bit more polypoid.

18:54

Then you see some nuclear material right there

18:56

that's a little bit bright, and then this

18:58

large fragment below it.

19:01

And the fragment signal is completely different than

19:06

this portion of the disc.

19:07

So you can assume correctly that you are dealing

19:11

with a free fragment that just butted right up against the

19:14

undersurface of the disc

19:15

and that this material popped right out of this hole.

19:18

And there's also some other findings.

19:20

If you look out in the, in the periphery of the spine,

19:23

you can see there's some foraminal stenosis and,

19:26

and that'll be a, a story for a little bit later.

19:28

And also for another day is another example

19:33

of a disc herniation free fragment type.

19:37

The fragment is butted up against

19:39

the L five S one disc space, which is polypoid in in shape.

19:44

And so there, there is an extrusion, there's a free fragment

19:47

or sequestration with the extrusion.

19:49

But notice the color difference or shade difference.

19:52

This is lighter gray. This is darker gray.

19:54

Yes, they're right next to each other,

19:55

but they're not really attached to one another.

19:58

Then we get into the, the axial zone of involvement.

20:03

This is off to the side in the recess area,

20:06

it's in the infra particular area.

20:08

This is at L five S one. So here's L five.

20:12

And this one is compressing the descending

20:15

S one root sleeve and it's pretty big.

20:17

Remember at L four five the nerve coming out is

20:21

gonna be at L four.

20:22

At C four five, the nerve coming out is going to be C five.

20:27

And that's a little bit confusing to you newcomers.

20:30

Now I use disc signal a lot.

20:32

I use it to to, to identify the disc abnormality.

20:35

And sometimes I use it to decide how acute, how fresh,

20:39

how active a di a disc is.

20:41

Caution, the signal intensity of discs tends

20:46

to be much darker on T two faine echo than it does on any

20:50

of the other water weighted sequences.

20:52

So you may, may be better off deciding if it's desiccated

20:56

or calcified on a proton density, fat suppression

21:00

or a gradient echo image rather than a faine echo T two,

21:03

which makes the discs darker than they

21:06

otherwise might appear as an example of a cystic disc.

21:10

Is that possible? It sure is.

21:12

You can bleed into, into a disc, it can liquefy

21:15

and that's what's happened here.

21:17

This is a, a bloody disc fragment

21:20

that is very bright on the T two weighted image.

21:22

And most of you that look at brains know that this is,

21:24

this is not, uh, atypical for the signal of longstanding

21:29

blood cavities in the brain.

21:31

Just grab a sip of water here.

21:39

Another type of herniation is a herniation

21:41

that can occur into the osteochondral endplate.

21:45

Now the, these can be symptomatic,

21:47

especially when they're, they're acute.

21:50

This tends to be more common in people

21:52

with connective tissue abnormalities.

21:54

Uh, you can also see something very similar

21:57

to it in a disease process.

21:59

I'll show you in, in a few moments.

22:01

So downward herniation

22:02

through the osteocondral end plate is known

22:05

as a sch smalls node.

22:07

They can be quiescent or they can be symptomatic.

22:10

The ones that are symptomatic are almost invariably gonna

22:14

demonstrate vertebral edema,

22:16

so-called modic one type change,

22:18

which we will cover shortly.

22:20

There's an example of what I would consider a bland inert

22:25

subclinical sch smalls node isolated

22:28

to the inferior nplate of L three.

22:32

And we can see very nicely the osteochondral nplate

22:36

and the annulus volume average together.

22:39

So we can't separate them very well.

22:41

Anterior annulus, posterior annulus.

22:44

We cannot separate very easily the PLL at this resolution

22:48

from the posterior annulus.

22:50

And the same thing in the front.

22:51

We cannot separate the anterior longitudinal ligament from

22:54

the annulus, but we do see our chronic

22:57

non emus subclinical schmall, no.

23:01

Now a term that's often thrown around, um, sort

23:05

of a wastebasket term is degenerative disc disease.

23:09

A term that my colleagues on the west coast like to use,

23:12

which I have adopted, um, is when there is

23:16

apophyseal hypertrophy

23:17

or in layman's terms, a spur either one or kissing spurs

23:22

and the disc material follows it.

23:24

And they're pretty large the term spondylosis deformans is

23:28

used, some people use it for all, all spondylosis.

23:32

And this can occur in the front, it can occur in the back.

23:34

And when it occurs in the back, we tend to use the term

23:38

disc osteophyte complex, which can be broad

23:41

or it can be pointed or or focal.

23:45

What else is in the family of disc degenerations desiccation

23:49

of of the disc, displacement of the disc.

23:53

Osteo KDRs, as we've already talked about, you know,

23:56

implosion into a degenerated pl disc, fishering

24:01

disc space narrowing.

24:03

And again, as stated, osteochondral nplate,

24:06

cartilage erosion, all of these things are components

24:10

of degenerative disc disease.

24:13

So let's take a look at an example of somebody

24:16

with degenerative disc disease.

24:17

I I think this looks a lot like the condition known as

24:21

ankylosing spondylitis with Anderson lesions

24:24

and Romans lesions, except it's an 18-year-old man

24:28

and kind of be very atypical for ant spon.

24:31

But look at what's happening

24:32

with these implosions into the osteo conal nplate.

24:35

They are clearly, clearly emus

24:39

and this is somebody with active schmos nodes

24:44

and it's either ant spa in an, in an 18-year-old

24:47

or it's going to be as it was in this case, uh, somebody

24:51

with a connective tissue problem.

24:55

Let's now talk about the modic grading system for

24:59

looking at the nplate complex.

25:02

The osteocondral nplate complex modic one

25:06

osteo edema low on T one, high on T two, fast spin echo.

25:12

Um, these typically are seen in patients

25:14

with active movement abnormalities,

25:17

especially micro instability

25:19

or basically wiggling of one disc on the other.

25:23

In this group it can sometimes be very helpful

25:26

to get sagittal

25:27

or lateral flex X flexion extension views

25:30

of the lumbar spine for when they're lying down.

25:33

There may be no listhesis or retrolisthesis.

25:36

And when they stand up and they do flexion

25:38

and extension, you may see, uh, an or retrolisthesis.

25:44

When these heal, they progress to

25:46

fatty metaplastic replacement.

25:49

And this results in hyperintense T one signal.

25:55

They can be linear or hemis spherical.

25:58

It can be in the middle, it can be eccentric.

26:01

And, and this implies that there has been healing

26:03

of the original osteous insulin.

26:07

Then modic three hypot intense sclerosis.

26:11

So low signal on all pulsing sequences.

26:14

The fatty metaplasia is bright on T one

26:17

and if you do a fat suppression image, you'll,

26:19

you'll barely be able to see it

26:20

because it will suppress can these coexist?

26:23

Of course they can 'cause this becomes that.

26:27

This is the healing phase of modic one.

26:29

So it is not uncommon if you really look carefully

26:32

to see both a combination of edema

26:35

and fatty metaplasia at the same end plate.

26:39

This is just a summary slide.

26:41

I don't think it delivers too much information showing

26:44

what you see in, uh, modic one and modic two

26:48

and modic three, and I'm gonna skip over it.

26:50

You'll notice that on the sclerotic modic three,

26:53

the nplate is low in signal or low in density intensity,

26:58

but that is almost identical from the T one to the,

27:02

to the T two weighted image.

27:05

Let's move on now to, uh, an example of of e modic One,

27:10

this is a 40-year-old man with low back pain,

27:14

stabbing pain worsening and severity

27:16

and the disc has lost height.

27:20

But unlike most disc spaces that have lost height

27:23

that are desiccated, that lo lose prot glycan

27:26

and lose signal, this one is very emini.

27:30

The endplate is being, I wouldn't call it destroyed,

27:33

but it's being invaded by multiple small fingers

27:37

that are coming from the degenerative disc space.

27:39

Now, unlike discitis, the endplate is still there.

27:42

If you look at this T two weighted image,

27:44

you can see the endplate

27:46

and the amount of edema

27:47

around the endplate is less than 50%.

27:49

There's no holo vertible edema like you see in

27:52

infectious discitis.

27:54

There's no anterior soft tissue mass.

27:56

There's no posterior soft tissue mass other than the disc.

28:01

And so you wouldn't want to confuse this

28:04

micro instability modic one change.

28:08

And it's a common mistake with disco

28:10

vertebral osteomyelitis.

28:13

Now, if you're really drilling into this case and,

28:17

and I am you'll, you'll see right here

28:20

that there's a little tongue hanging down right there.

28:24

There it is. It's right in front of S one.

28:26

Not so apparent here or here,

28:30

but definitely apparent as we moved off to the side.

28:33

See this is midline. This is off to the side.

28:36

So you have to figure out where you are

28:39

and then we look at the axial and it's a no-brainer.

28:43

Now this is an example of somebody with a very large disc

28:47

and if you use strict criteria,

28:49

the base is wider than the apex.

28:51

You would call it a protrusion type herniation.

28:53

It is not, it is squiggling down.

28:56

It's a proven case, it's an extrusion type herniation.

28:59

It is compressing S one

29:01

and it's showing you an example

29:02

of the not uncommon exception to the rule.

29:06

WHI, which is not all the time

29:09

or extrusion, is gonna have a narrow base

29:12

and a wide apex is another example

29:16

of modic one change right next to it is a large spur,

29:20

so-called spondylosis, deformans at L one two at L two three

29:24

with the patient lying down, there's a little bit

29:27

of retrolisthesis of L two on L three.

29:30

That's not uncommon when they stand up.

29:32

This may reduce when they bend over, it may slide forward.

29:36

We don't know yet until we do flexx views,

29:38

but this is absolutely a candidate for flex X views.

29:42

The inflammation enhances,

29:45

it stays pretty close to the disc space.

29:47

So this is not an infection. And why is the disc moving?

29:50

It's moving because the facets are awfully sick.

29:53

Look at those sclerotic hypertrophy.

29:56

Irregular, frankly, for lack of a better term, ugly facets.

30:00

And yes, there is a posterior mass up up here,

30:03

which I'm not going to discuss today isn't necessarily part

30:06

of the teaching aspect of this case.

30:09

Let's look at modic one and two.

30:12

We have osteo KDRs with innumerable sch smalls notes

30:16

on the T two without fat suppression.

30:20

There is this high signal.

30:21

Now is that, is that fat or is that edema?

30:25

Well, fat tends to be more hemis spherical

30:28

and edema tends to be more linear.

30:30

But you just go over to your fat suppression image,

30:33

you don't even need to call up the T one.

30:34

You can save yourself some time.

30:37

And at this level, I think it's T 12 L

30:39

one, the fat suppresses.

30:41

So this is a modic two change.

30:43

Then we go down to L four five,

30:45

some rather large osteo chondro sch smalls nodes,

30:49

degenerative disc disease, loss of dis space height

30:52

and desiccation, some retrolisthesis.

30:55

And this time we have edema,

30:58

increased intensity on the water

31:00

weighted fat suppressed image.

31:02

So modic one on the bottom, modic two on the top.

31:08

A mimicker of modic changes is ankylosing spondylitis.

31:13

Frequently you'll have edema,

31:15

an active ankylosing spondylitis, um,

31:18

in the center of the disc space.

31:20

These are known as an Anderson lesions in the periphery.

31:24

These are known as Romans lesions.

31:27

And these Romans lesions when they heal,

31:29

just like other parts of the body

31:31

and musculoskeletal, MRI healing begets fat.

31:36

So the healing and treatment

31:37

of ans spam will often beget fat.

31:40

And these hemis, spherical fatty areas may be confused

31:43

with micro instability from facet disease when indeed

31:47

they're related to a primary inflammatory process.

31:51

Let's talk about listhesis.

31:54

This is something all radiologists like to talk about

31:57

'cause we've all looked at so many, uh, cervical,

32:00

thoracic and lumbar spines.

32:01

The first type of listhesis I like to tackle is apophyseal

32:06

listhesis listhesis related to a severe

32:10

arthropathic facet.

32:11

This is a form of degenerative, this is a form

32:14

of degenerative disease of a joint, the facet joint.

32:18

Now sometimes the facets will be distended with fluid.

32:22

I call that the distended facet sign.

32:24

It is in those patients where you really should consider,

32:27

if you don't have listhesis in the non-dynamic position,

32:31

you should really consider the flexx lateral flexion

32:34

and extension views

32:36

because a, a good number

32:37

of those patients may be more than 50% will have movement

32:42

in apophyseal listhesis from degenerative facet disease.

32:47

The central canal becomes small.

32:50

This is very important and the ligament

32:53

and flam become large.

32:54

This is also very important.

32:57

The foramina off to the sides are usually spared.

33:02

This is a great little tip.

33:04

If you can remember these tips on this slide

33:07

and nothing else, I think it will be of value to you.

33:11

The next type of listhesis is spondylolysis related

33:15

stress fracture related listhesis occurs in younger

33:19

individuals, usually athletic individuals

33:21

who get pushed back due to hyperextension

33:24

and with long pedicles,

33:26

the facets may be secondarily affected.

33:29

So you may have pretty massive facet arthropathy even though

33:32

you also have a longstanding

33:36

spondylolysis in say a 60-year-old.

33:39

But here are some tips if you're having trouble identifying

33:42

the defect, which is gonna be challenging if you're not a

33:45

spine reader, but most spine readers can,

33:48

can do it and do it accurately.

33:50

Look at the foramina.

33:51

If the foramina are narrowed

33:53

and the central canal appears stretched from A to P

33:57

you're dealing with spondylolysis related listhesis, even

34:01

with the big facets.

34:03

Then we have the traumatic form of listhesis

34:08

and the traumatic form of listhesis.

34:09

You're catching a spondylolysis type event, um,

34:15

right at the moment, you know,

34:16

with within a few weeks of its onset.

34:19

And you may see fractures of the pars.

34:21

You may also have complex unstable fractures

34:24

with listhesis in the cervical region or other locations.

34:27

You can have fractures of the lamina.

34:29

It's basically an insult of the posterior column, uh,

34:32

of the spine, which is divided up into anterior, middle

34:35

and posterior columns.

34:37

You may or may not have a a ligamentous injury,

34:40

but most young individuals that have an acute pars injury,

34:45

one of your jobs is to figure out,

34:47

do I see a cortical breach?

34:49

And if I see a cortical breach, is it on both sides

34:52

of the bone or is it on one side

34:54

or is it simply just an intramedullary pattern of edema?

34:57

So you can start drilling further

34:59

and further into these acute traumatic forms

35:02

of injury and listhesis.

35:05

Let's take an example of spondylolisthesis

35:09

in a grown adult.

35:11

Now this is not a 15-year-old, this is a 50-year-old.

35:14

You can see the small node up high as a sign of disc space.

35:20

Osteo KDRs, I think at T 1112.

35:22

Then we go down here at L five S one

35:25

and we've got some slippage.

35:26

Now I always describe how much slippage there is.

35:29

I eyeball it, sometimes I measure it,

35:31

but most of the time I eyeball it.

35:33

This one's about five to seven millimeters.

35:36

And you know, if you sat there

35:37

and measured every listhesis,

35:38

you'd never get through the day.

35:40

So I'm, I'm giving you some just practical

35:42

tips on interpretation.

35:44

And then here in the axial projection there is the

35:46

spondylolysis defect.

35:47

But here's the tip off, look at

35:50

how the thecal sac looks like gumby,

35:53

it's being stretched from anterior to posterior.

35:57

This is a great little tip that tells you you're dealing

36:00

with spondylolysis related listhesis.

36:03

Even though the facets nearby may be sick.

36:06

Let's go to that foramen, that poor L five root getting

36:11

scrunched by this disc that is uncovered due to

36:17

spondylolisthesis and anterolisthesis.

36:20

Look at the other foramen, the nerve root is completely

36:24

and totally obliterated.

36:30

All right, so here's a patient that's lying down different

36:33

patient this, this time the patient has

36:37

apophyseal related listhesis,

36:39

but it's not anterolisthesis, it's retrolisthesis

36:42

because the patient is lying down.

36:45

So L two is sagging on L three. What if you stand 'em up?

36:49

It might still be there, it might reduce.

36:51

What if you do flex X views, they may as they did

36:55

move anterior on flexion and move posteriorly on extension.

36:59

That's why you do it. You also have another clue.

37:02

You've got both modic one change, a little bit

37:06

of fat right there, right on T one

37:08

and a lot of modic one change.

37:10

So modic two fat modic one edema telling you

37:16

that there is movement between L two and L three.

37:20

And then to top it off, the cherry on top is the distended

37:25

facet capsular sign that

37:29

suggests very strongly

37:30

that this is an apophyseal related form of listhesis.

37:34

The forer were fine.

37:36

All the stenosis is in the central canal

37:39

and the thecal sac doesn't have

37:40

that gumby stretched out look to it.

37:44

Alright, here is a cervical spine.

37:47

I said I wasn't gonna show you too many of these.

37:48

There's a patient with neck pain,

37:50

but it's a very nice example of

37:53

two different teaching points on the same patient.

37:57

Almost on the same slide. Let's go to the middle.

38:01

We look very carefully see how difficult it is

38:03

to spot the cortex

38:04

and separate it from the posterior longitudinal ligament.

38:07

Challenging. But one tip off is that when you go back,

38:13

that disc tapers and the bone becomes very pointy.

38:18

So posterior tapering suggests very strongly

38:22

that you're looking at a disc osteophyte complex.

38:26

Some of you may have used the term covered disc, some

38:30

of you may have used the term spondylotic protrusion.

38:33

But the correct term these days is discosified complex

38:38

focal or broad.

38:39

And where it is, is it in the middle? Is it in the recess?

38:43

Is it in the foramen?

38:44

Now let's drop down a little bit and look right here.

38:50

And this time we have, we have a spur.

38:54

No doubt there's a spur in the front,

38:55

there's a little spur in the back,

38:57

you're having a hard time separating the cortex right

39:00

there from the disc space.

39:02

Everything's kind of dark,

39:03

but there's your bright little glob, your bright bulb.

39:08

So remember signal intensity can really be your friend.

39:10

It was here, it was right there. It's a little bit gray.

39:13

You get off to the side, it's a little more emus.

39:16

So this is the cherry on top.

39:18

You've got a ified complex,

39:20

but on top of it you have an extrusion type herniation

39:24

and maybe even a free fragment brewing

39:26

because it's hard to connect the two by signal and or shape.

39:32

So here's our axial projection, our extrusion

39:38

off to the side and the right neural foramen at C six seven

39:41

is kind of gray on T one,

39:44

it's bright on the water weighted image

39:46

and sometimes you may have to use something

39:48

that's a little more water weighted even than

39:51

the fast and echo T two.

39:52

This time the fast spin echo T two worked

39:56

there is your disc extrusion

39:58

and which root is it compressing At this level

40:02

it is compressing C seven.

40:05

Then we go to C 5 6 1 level up where we had a our spur.

40:10

Our spur is pretty broad

40:13

but it's focal on the left side, it is compressing,

40:16

exiting C six and a little bit of the left hemi cord.

40:21

Dark right tapered on the sagittal,

40:26

non tapered on the sagittal,

40:28

and in fact expanding like a mushroom.

40:33

Now there are a few pulsing sequences

40:35

that can help you a great deal

40:36

and I really needed my pen to illustrate this, but I'll try

40:41

and illustrate it anyway,

40:42

here's a sagittal fast and echo T two.

40:44

And there's definitely a contour change at C four five

40:48

and probably at C five six with some desiccation

40:52

and some loss of disc space height.

40:54

So what are we gonna call this?

40:56

So you have to go back and forth between your sagittal

40:59

and your axial, your axial and your sagittal.

41:03

And this is a gradient echo.

41:05

This is a very water sensitive gradient echo image.

41:09

I could have used a proton density fat suppression image.

41:12

But here's what's happening.

41:13

There is a spur here

41:15

and if you go thin enough, you may catch the spur on top,

41:20

then you may catch the little disc that goes with it.

41:23

And then if you look at the next slice underneath it,

41:26

you'll see another spur right in the midline.

41:28

So there'll be spurs kind

41:30

of encasing this little bit of this material.

41:32

So you don't wanna call this a protrusion type herniation.

41:35

It's actually because you're so thin,

41:37

because your image quality is so high,

41:40

you are just catching the, the material that's in

41:43

between the two spurs.

41:45

Now there is an annular tear here

41:47

that's this high signal intensity in the periphery.

41:49

So again, I would encourage you to toggle back

41:52

and forth between your sagittal and axial and I

41:55

and I honestly could have illustrated it a little

41:57

bit better with my pen.

42:00

Let's take a look at these sagittal, uh,

42:03

fat suppressed water weighted images.

42:05

And this time we've got a a cord lesion.

42:09

Now let's look at the disc spaces.

42:11

Um, this one is mostly covered.

42:13

If you look right there, there's the cortex,

42:15

there's the PLL.

42:17

So if you put the cortex into it, the cortex is covering

42:21

that retrolisthesis and disc.

42:23

So it's covered. That is a disc ified complex.

42:27

Whereas you go one down, there's a mushroom,

42:32

there is your mushroom

42:35

and then there's also a cord injury.

42:37

This is a 73-year-old man, God bless him.

42:40

He was skiing and snowboarding and had a fall.

42:44

So he's, he sustained a cord injury.

42:47

But this case is emphasizes the importance of being able

42:51

to expediently quickly and efficiently go back

42:55

and forth between the SAG and ax using your PAC system.

42:59

Yes, there is a left hemi cord injury that is confirmed,

43:02

but right there on this axial gradient echo image,

43:05

there's your extrusion.

43:07

That wasn't as easy to mine on the sagittal

43:11

as it is in the axial projection.

43:13

Thus demonstrating the value of MultiPro projectional, uh,

43:17

MRI and gradient echo very good at picking up the water

43:22

emphasis and edema

43:23

and sometimes hemorrhage that exists

43:25

inside these acute disc abnormalities.

43:29

Now some of you may be performing fast

43:32

and echo three DT two imaging

43:34

and doing reconstructions of the whole spine.

43:37

I suspect it's the minority of you,

43:40

but you can reconstruct anything.

43:42

I, I do think when you know, we, we get into, you know, some

43:46

countries that are paying $80 for an MRI,

43:49

you're gonna have no choice.

43:50

You're gonna have to do one pulsing sequence in five

43:53

minutes and be done.

43:54

And by the way, this is already happening.

43:56

I know for a fact, uh,

43:58

some countries in Europe are paying $80 global for an MRI.

44:04

So efficiency is gonna be more

44:06

and more important as time goes on.

44:07

But here we have uh, the neural foramen

44:10

with foraminal narrowing all reconstructed in the sagittal

44:14

oblique for the cervical spine.

44:16

And you can also do the same thing for the lumbar spine.

44:20

Now I wanna finish up and save some time for questions.

44:23

I wanna show you a few things that go bump in the

44:25

night with some frequency.

44:30

I had an adrenal mass, I had a renal cell carcinoma.

44:35

I think those are things that you radiologists

44:37

that do general radiology

44:39

and spine are gonna pick up readily.

44:41

Look at your scalp, don't just look at it, read the scalp.

44:46

You are not gonna get sued over a disc herniation

44:49

if the patient doesn't have surgery immediately

44:52

for the disc herniation, you're doing the patient a favor.

44:56

Whereas if you miss a renal cell carcinoma,

44:58

you are not doing the patient a favor.

45:01

If you miss a pancoast tumor on a cervical spine,

45:04

you are not doing the patient a favor.

45:07

Look at the extra spinal structures.

45:11

Now this is something that goes

45:12

bump in the night in the spine.

45:13

Yes, there is a sch small node down here,

45:15

but this is a fat containing hemangioma

45:18

that demonstrates the typical speckled pattern

45:22

that you see in hemangiomas.

45:24

It's a fat rich hemangioma.

45:26

Is there such a thing as a fat poor hemangioma?

45:30

Absolutely Just like they're are fat rich

45:32

and fat poor adrenal adenomas, the fat poor ones tend

45:36

to be round slightly lobulated with the same basic shape

45:40

as the hemangioma of the liver.

45:42

And on the T two fat suppression, proton density,

45:45

fat suppression image, they're going

45:47

to be very, very bright.

45:49

What's the ratio about three

45:51

or four to one fat containing versus not fat containing

45:55

but not uncommon.

45:57

And by the way, a little bit of vacuum phenomenon starting

46:00

to occur here anteriorly at T 12 L one.

46:05

Here's another example of something

46:07

that might go bump in the night.

46:10

Yes, you do have disc displacement abnormalities at L four

46:13

five with modic hemis spherical type two

46:18

fatty metaplastic and plate change.

46:22

But look at this vertible body at L two,

46:24

it's kind of speckly looking.

46:27

It's very squared off and it's big.

46:30

This is what Paget's disease looks like when you stumble

46:33

into it in the lumbar spine.

46:37

There's another weird pattern that most

46:39

of you probably haven't seen

46:41

and this is the intercept procedure int intercept procedure,

46:45

which is an ablation that occurs

46:47

where the Bai vertebral veins come in.

46:49

So do nerves come in in that location

46:51

so you can attenuate back pain by, you know,

46:55

putting a needle in and doing ablations at the Bai vertebral

46:59

plexus tip, which was done in this patient to

47:03

attenuate nerve pain.

47:06

Now here's a patient with an abnormality from a prior fusion

47:10

anterior plate screw construct.

47:12

Now one point of interest, no matter where you are lumbar or

47:16

or cervical, it's very common for the adjacent levels

47:20

to bear the responsibility of flexion

47:24

and extension in an unfair fashion around a fusion.

47:27

So we call this adjacent level disease.

47:30

Yes, there's an abnormality at C3 four.

47:33

Yes, there's some spondylosis

47:34

and discosified complex at C six seven.

47:39

And yes there is a cord abnormality post-surgical, an area

47:42

of non-cystic myelomalacia or gliosis.

47:45

That's now why I'm showing the case.

47:47

The patient presented

47:48

with pain going down both arms for three months.

47:51

That's true. But when I question the physician on a phone

47:55

call, the patient has been been having visual symptoms

48:00

and a pain in the occipital region, which is a very common

48:04

symptom complex for this disorder.

48:07

Look at the, look at the pituitary.

48:09

It's on every single cervical spine. The pituitary gland.

48:14

Look at the pituitary.

48:16

If you have a middle aged woman

48:18

and she's coming in with quote unquote neck pain

48:21

and she's got a an empty cell, especially

48:23

with an expanded cell, you've gotta worry about

48:27

idiopathic intracranial hypertension

48:29

and suggest an MRI of the brain previously known

48:32

as the entity Pseudotumor Cerebra.

48:36

And this patient has pseudotumor cerebra also accompanied

48:40

by distension of the optic sheath.

48:42

Sometimes the ventricles will appear a little small,

48:45

sometimes the cerebellar tonsils will sag just a little bit.

48:51

There's another entity that goes bump in the night.

48:53

Most people don't anticipate that they're going to have

48:57

intrathecal arachnoid scarring,

48:59

especially if there's been no surgery and there hasn't.

49:02

There's facet disease out the yin yang. It's terrible.

49:06

There are disc displacement abnormalities

49:09

to be further characterized at another time

49:11

with modic type two fatty metaplastic nplate changes

49:16

out the yin yang.

49:18

But the patient's main problem is right here.

49:20

You've got these two eyeballs at L three four.

49:24

We all know that there should be innumerable nerve

49:27

roots at L three four.

49:29

They're just kind of stuck together

49:31

and this is the nerve root clumping sign

49:33

of arachnoid scarring.

49:35

So all these other things might be symptomatic.

49:37

That is her main problem.

49:40

Don't forget that you're gonna get the upper sacrum,

49:42

not the whole sacrum, but you're gonna get the upper sacrum

49:45

when you do the lumbar spine.

49:47

So this patient had right buttock pain

49:49

but also fortunately had sacral pain.

49:51

So they carried the exam down a little bit

49:53

and this patient had right sided sacroiliitis with

49:57

modic ish type changes.

50:00

Osteo edema on either side. And now you have a differential.

50:03

Are you're dealing with ra, are you dealing with anang spon?

50:06

Are you dealing with something rare like familial

50:08

mediterranean fever or SLE?

50:10

There's a differential here that you must pursue

50:13

but you at least made the finding

50:15

and here it is in the coronal projection.

50:17

Look at these tiny little erosions in this patient

50:20

with unilateral, uh, unilateral inflammation

50:24

of the SIJ in this patient with egg spine.

50:29

So let's summarize and then I'll take a few questions.

50:33

When you are looking at your spine,

50:36

maybe one system you could use, this is just a suggestion,

50:40

is you, you look posterior,

50:41

you look lateral, you look central.

50:44

So posterior you got facets. How big are they?

50:47

Are they distended? Do they have fluid?

50:50

Are they sclerotic, are they eroded?

50:53

Is there a synovial cyst?

50:54

If there is, what is it encroach on

50:57

and is there canal stenosis from the facet and leg flam?

51:02

I look at the leg flam.

51:04

I don't measure it because I'm very good at picking up

51:06

about six millimeters.

51:08

So I can tell if it's bigger than six or less than six.

51:11

But you can measure it to start to train

51:13

and educate your eye.

51:15

If you sit there measuring leg flava, you'll have a seizure,

51:18

eventually you'll wear out.

51:21

So I, I do look at the thickness, I comment on it,

51:24

I describe whether it's contributing to stenosis

51:27

and I especially look at the recesses,

51:30

which you now know their position sarcopenia,

51:37

Lemme grab some water here.

51:43

Sarcopenia. This is something

51:45

that most people don't comment on,

51:48

but it's extremely important in the flexion and extension

51:51

and control of the vertebral bodies relative to one another.

51:55

For if you have no muscles,

51:56

you're gonna put undue stress on your ligamentous structures

52:00

and on your osteochondral, NPLS and annulus fibrosis.

52:03

So I characterize it as mild, moderate, and severe.

52:07

And there are percentages applied to these 25% loss,

52:10

50% loss, greater than 50% loss.

52:13

I honestly, I just eyeball it

52:15

and I also describe whether it's symmetric or asymmetric

52:18

and I include it level by level,

52:20

but I do it pretty quickly laterally.

52:25

You already know where the recesses are from our,

52:27

our discussion of zones.

52:29

Then we get to the foramina.

52:31

There's a, a proximal foramen and a distal foramen

52:34

or there's a main foraminal canal

52:35

and an extra foraminal canal.

52:37

I don't care which terminology you use.

52:40

That currently accepted terminology is foraminal

52:42

and extra foraminal.

52:44

And some of your colleagues divide the foramen

52:46

up into three zones.

52:47

Uh, that's okay to do. Uh, the pedicle is the pedicle emus.

52:53

Is there a pars fracture? How many cortices are involved?

52:56

And guess what happens to the pars fracture when it heals,

53:00

it becomes fatty.

53:03

So if you look at a 19-year-old

53:05

and you see fat signal in the pedicle

53:07

or the lamina, in all likelihood

53:09

that patient had sustained a stress injury

53:12

of those structures.

53:14

Fat is a terrific marker.

53:17

And we go to the central part of the, the canal is there,

53:21

is there stenosis?

53:23

Mild, moderate, severe?

53:25

There's something called the toric Pavlov ratio,

53:28

which we use in athletes in the cervical spine,

53:30

which you can Google at the conclusion of this talk

53:33

a little bit beyond our discussion today.

53:36

But we use this as a monitoring tool to see

53:38

who can play contact sport or not.

53:42

We're also gonna look at the contribution of listhesis

53:45

to the central canal.

53:47

Apophyseal listhesis narrows the central canal

53:50

spondylolisthesis, widens from front

53:52

to back the central canal.

53:55

And then we're gonna comment on the discs themselves,

53:58

whether there's degeneration, whether there's loss

54:01

of disc space height,

54:02

and the modic grade of osteochondral nplate disease, one,

54:07

two or three edema fatty metaplasia

54:12

and or sclerosis.

54:14

With that, I will take some questions.

54:18

Thank you so much for your lecture Dr. Pomerance.

54:20

Yes, we are going to open the floor for some questions.

54:23

We've got a couple in our q and a box so far.

54:28

Um, can you explain extrusion

54:31

and can migration occur in protrusion?

54:33

It's hard for me to hear you.

54:35

I'm sorry. Can you explain extrusion

54:38

and can migration occur in protrusion pro?

54:42

Can I explain extrusion

54:43

and can migration occur with with protrusion?

54:46

Unfortunately migration can occur with protrusion

54:49

because you're talking about stretching the annulus.

54:51

So if the annulus stretches down,

54:54

then it's gonna migrate a little bit.

54:56

But when you have a protrusion

54:58

that extends down a little bit,

55:00

that one reliably is gonna have the broad base

55:03

and it's not gonna go very far.

55:04

Maybe a millimeter

55:05

or two, it's not gonna go a centimeter

55:08

away from its location.

55:09

So can it occur?

55:11

Yes, it can occur, but it's far more likely when you have

55:14

migration up or down that you're dealing with an extrusion.

55:18

What was the second part of the question?

55:22

It was, can migration occur in protrusion?

55:26

Yeah, I think I answered that.

55:27

Okay. Oh, an explain extrusion. Yep, that was

55:30

It. Yeah, so extrusion,

55:31

lemme try one more time with my

55:34

trustee drawing tool.

55:35

Oh, it's working. Wow. I wish I'd known that earlier.

55:39

So, um, you know, here's your extrusion, here's your nucleus

55:44

and then I'll make you an annulus.

55:46

I'll make you an annulus right there.

55:50

And then there's one other, there's one other rim, whoops.

55:53

There's one other rim and that's the apophysis of the bone.

55:56

So the apophysis of the bone is layered right up against the

55:59

annulus like this.

56:03

And then when you have a, let's see if we can move that,

56:10

then when you have a herniation,

56:12

the nuclear material is gonna go right through a tear.

56:15

It's gonna go right through the annulus, it's gonna come out

56:17

of the nucleus and it's classically,

56:20

it's gonna look something like this.

56:22

So let me lemme draw it a little better

56:26

'cause it's gonna be narrow when

56:27

it goes through the annulus.

56:28

It's gonna get pinched by the annulus

56:30

and that's a better description of it.

56:33

Now what can happen is it goes under the ligament.

56:37

Can you move this bar? There we go. I've moved it.

56:41

So if you're going underneath the ligament,

56:44

let's draw the posterior longitudinal ligament.

56:46

The ligament's gonna squish this thing

56:48

backwards, it's gonna flatten it.

56:50

So that's the reason why, again, you can't use that apex

56:54

to base rule as your sole determinant,

56:57

as your only major determinant

56:59

of whether you have an extrusion or a protrusion.

57:02

I wanna draw one other thing for you.

57:03

Now that I know my drawing tool is working, I want to draw

57:07

that weird gradient echo case that I had, um,

57:12

and show you how you

57:17

volume average the disc material

57:19

and had a like a little spur here.

57:21

So you had the spur

57:23

and then if you get really, really thin,

57:25

I'll make the disc brown.

57:30

And then you just happen to catch the disc in between.

57:33

Your sections are extremely thin

57:37

and your axial just catches the disc right in between.

57:40

And let's say there's a little annular tear right

57:42

here, we'll make that purple.

57:46

You get a little bright spot volume average below that spur

57:50

and above that spur.

57:51

So in the axial that can be misleading

57:53

and you end up with something

57:54

that looks a little bit like this on that one, just

57:56

that one cut, just that one cut

58:01

'cause above it is gonna be a spur

58:03

below it is gonna be a spur.

58:05

Again emphasizing how important it is to toggle back

58:08

and forth between the sag and the ax.

58:13

Any other questions?

58:15

Yes. How about this one?

58:17

How do you decide on your threshold

58:18

for calling neural compromise?

58:20

Do you use terms such as touching and compressing?

58:25

Great question. So

58:27

how do you decide on the terms you use for nerve compromise?

58:33

So everybody's kind of got their own system there.

58:36

Uh, but, but I'd say if you're pretty good with English

58:39

and you're a common sense person, here's how I,

58:43

here's how I do it.

58:45

If, if I don't have any nerve compression, but the nerve

58:48

and, and it's really a mild abnormality,

58:50

I'll say the nerve is displaced but not contacted.

58:54

Or if I wanna dial up the heat a little bit,

58:56

I'll say the nerve is displaced and contacted.

59:01

If I want to dial up the heat even further,

59:03

the nerve is displaced and compressed.

59:06

If I want to dial up the, the heat a little more,

59:09

I'll say the nerve is displaced and severely

59:12

or markedly compressed.

59:14

That that's, that's how I do it.

59:17

Great. Alright, one more.

59:20

Describe your method of distinguishing an acute hernia

59:22

herniation versus a chronic herniation.

59:26

Yeah. So describe

59:27

how you distinguish an acute versus a

59:30

chronic, uh, herniation.

59:31

That is a tough one

59:32

and that is something that almost every spine

59:35

and radiology imager on this, on this teaching, uh, vignette

59:40

and seminar is, is get getting asked by

59:45

personal injury attorneys and malpractice attorneys and,

59:47

and all kinds of folks.

59:49

And here are a few things that help you decide it is acute.

59:53

Now you may not always be able to tell,

59:55

but if there's underlying spondylosis,

59:58

if the disc is desiccated, if it's not very bright,

60:02

if it has no hemorrhage, if there's no bleeding

60:05

or swelling of the posterior longitudinal ligament,

60:08

those are the things that I use to decide

60:11

that something is acute.

60:13

Now if, if I have none of those,

60:15

then I usually fall into the camp of,

60:18

I'm not sure I can tell, but it's more likely chronic.

60:21

Now if it's completely calcified

60:23

or it's completely covered by bone.

60:26

In other words, if it's a discs osteo fight, there's no way

60:29

that I'm gonna call that a herniation.

60:30

So I I'm not gonna give them the license to prosecute that,

60:34

that specific, uh, case.

60:37

But if I have any of those things, blood edema,

60:42

PLL swelling, um, and, and a and a paucity of calcification

60:46

or a paucity of spondylosis, uh, I'm going to call

60:49

that an active and likely traumatic, you know, herniation,

60:53

extrusion type, protrusion type,

60:54

free fragment type, et cetera.

60:58

Thank you. I think we'll end it there. Dr.

61:00

Pomerance, thanks for answering those questions

61:02

and thanks for your lecture today.

61:04

Appreciate you Ashley. Yeah, everybody, thank you.

61:06

Thank you so much and thanks

61:07

for everyone else participating in our noon conference

61:09

and asking such great questions.

61:11

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61:13

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61:15

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61:17

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61:20

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61:24

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61:25

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61:28

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61:30

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61:33

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61:35

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61:36

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61:39

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