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Hello and welcome to Noon Conference, hosted by Modality

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Today we are honored to welcome Dr.

0:25

John Jonathan Samit for a lecture entitled Ultrasound

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of Peripheral Nerve Injury.

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Dr. Samit is Associate Professor

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of Radiology at Northwestern University.

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Feinberg School of Medicine serves as the division head

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of Body Imaging and section head of MSK imaging at Anne

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and Robert h Lurie Children's Hospital

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and works in the adult MSK radiology section at

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Northwestern Memorial Hospital.

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Dr. Sam's interests are in nerve imaging with MRI,

0:57

neurography and ultrasound Rapid MSK imaging

1:01

and MRI techniques for bone marrow evaluation.

1:04

At the end of this lecture, please join Dr.

1:06

Sam in a q and a session

1:08

where he will address questions you

1:10

may have on today's topic.

1:11

Please remember to use the q

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

1:15

as many as we can before our time's up.

1:17

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

1:20

Sam, please take it from here.

1:23

So, uh, my name is John Samit

1:25

and I'm in Chicago at Lurie Children's Hospital

1:27

and Northwestern again.

1:29

Um, today I'm gonna be talking to you guys about

1:33

using ultrasound for peripheral nerve evaluation.

1:44

So in this talk we're gonna review the nerve anatomy

1:48

and we're gonna go over the ultrasound protocol that we use

1:52

and we're gonna focus on how to classify nerve injury,

1:54

which is, um, one of the most, uh, highly impactful,

2:00

um, exams and,

2:02

and, um, interpretations that you can provide

2:05

for your referring providers.

2:07

And the main thing is we want

2:09

to really separate a low grade versus a high grade nerve

2:12

injury for our peripheral nerve surgeons and, uh, doctors.

2:18

So when you look at a nerve, um, remember

2:20

that in cross-section there are

2:22

multiple things inside of it.

2:24

So the outer nerve has, uh, what is known

2:27

as the epi nearium, which will be hyper coic on ultrasound

2:31

that's marked in the yellow color there.

2:34

Within that, there are multiple fales.

2:36

The fales are going to be the light blue, um, things here,

2:41

tubes, the fas are bound by perineurium tissue.

2:46

Within that is even further, uh, iterations.

2:50

You have the axons bound by myelin sheath

2:55

and then in turn bounded by endoneurium.

2:59

So you have multiple fassal

3:00

that are gonna be hypoechoic on ultrasound.

3:02

We'll show images in a minute.

3:04

And in between those hypoechoic fassal are this orange

3:08

tissue here known as the inner epineurium.

3:11

So between the fassal you have this fibro fatty tissue,

3:15

which will be hyper coic.

3:16

So you get this alternating hypoechoic

3:19

hyper coic appearance.

3:21

Um, and you may have heard the terms honeycomb

3:23

or pseudo ovary appearance.

3:26

So here's what it looks like on ultrasound.

3:28

We're gonna see the outer epineurium is hyper coic,

3:33

multiple hypoechoic fales we can't see, um,

3:37

as well as we did on that image.

3:38

We can pretty much only see down to the fascicular level in

3:41

between the fassal.

3:42

This hyper coic tissue is that inner epineurium made up

3:45

of fibro fatty tissue.

3:49

You wanna see that the fassal are uniform.

3:51

There's not one that's just larger than the other.

3:54

Multiple small, similar appearing sized hypo coic

3:58

vesicles would be normal for the protocol,

4:02

we're gonna be using high frequency probes

4:04

and low frequency probes with ultrasound of nerves.

4:08

If you're tracing a nerve in an extremity, for example,

4:11

the nerve will go superficial.

4:13

We'll go deep and you have to be willing

4:17

to change out the probes, uh, during your examination

4:20

of even one nerve

4:21

because sometimes you might need a high frequency

4:24

for the superficial areas

4:25

and a low frequency when it goes

4:27

deeper and it's bound by muscle.

4:29

So for the high frequency probes, if it's a very small area,

4:35

you might want to use a, uh, hockey stick,

4:37

the little hockey stick probe.

4:39

Um, but we're gonna be using as high frequency as we can.

4:42

Every time I get this talk.

4:44

Uh, the number goes higher and higher.

4:47

Uh, but it, it really, really helps

4:48

to evaluate lower frequencies, as we said,

4:51

might be necessary for more deeper tissues.

4:55

The patient is gonna come with some kind of nerve palsy.

4:58

We have, um, in our medical record, uh, the ability to

5:03

ask the clinician to choose one

5:05

or two specific nerves that they want us to evaluate.

5:08

We're not just evaluating all the nerves in every case.

5:10

If there's a, um, if there's a, a palsy

5:15

or a nerve problem, for example, in the median nerve,

5:18

we're gonna trace the median nerve in the arm.

5:20

If there's a problem with the ulnar nerve,

5:21

we're gonna evaluate the NAR nerve.

5:23

So you really want to

5:25

have your clinicians tell you which nerve is the issue

5:29

and usually based on their physical exam, uh,

5:31

and there might be an EMG or nerve conduction study.

5:34

Um, they know which nerve they're worried about.

5:37

Sometimes they'll request multiple.

5:38

So as you see here, um, these are multiple different images

5:42

of different nerve evaluations.

5:44

This one is going to be the um, median nerve at the elbow.

5:47

Here is the ulnar nerve at the elbow,

5:50

median nerve at the wrist.

5:51

And this is the superficial radial nerve at the wrist.

5:55

So we're tracing these nerves throughout an entire extremity

5:58

because we don't know necessarily

5:59

where the site of injury is.

6:03

Here's just an example of, um, what you would do

6:07

to trace a nerve as you follow the CIC clip.

6:09

Notice how the median nerve

6:12

will change from superficial to deeper.

6:16

Um, it will be, uh, surrounded

6:19

by muscle in the forearm as a sort of a natural way of,

6:23

um, protecting the nerve.

6:27

When it is, um, in the elbow, you see

6:30

how it's more superficial.

6:32

So this is what you're doing.

6:33

You are tracing the nerve, you wanna see the nerve.

6:36

You see it right there in the middle is intact.

6:40

No transection, no aroma, no enlarged fascial.

6:45

So the advantages of ultrasound

6:47

and thinking of MR MRI as as the counterpart

6:49

and they are complimentary.

6:50

But the advantages of ultrasound is

6:51

that you can trace a nerve over an entire extremity.

6:54

Uh, with MRI, you have to kind of pick,

6:56

do you want really good imaging of the elbow or the wrist.

6:59

Um, if you try to image the entire

7:00

extremity can take a lot longer.

7:01

So ultrasound is nice 'cause you can really just say, okay,

7:04

I'm gonna evaluate the median nerve

7:05

through the entire extremity.

7:07

You can easily compare it to the other side.

7:09

For a normal control, everyone's a little bit different.

7:11

There's no exact measurements, especially in pediatrics

7:15

where a 2-year-old will be different than a 15-year-old.

7:18

So it's really just nice to compare it to the other side.

7:21

You can see the neural

7:22

architecture very well as I showed you.

7:23

It's nice to see the different fales.

7:26

If you have one enlarged fale, uh,

7:28

it really can bring it out on the ultrasound

7:31

dynamic imaging.

7:32

So for NAR nerve evaluation,

7:34

we're gonna show you how to do that.

7:35

Where you are are gonna be um, flexing

7:37

and extending the arm to see if the nerve will

7:40

sublux out of the groove.

7:42

In pediatrics, we love that it has no sedation radiation

7:45

or IV contrast.

7:47

And if there's metallic implants, surgical hardware, um,

7:50

we are able to see things with ultrasound

7:53

that we may have a very difficult time on MRI seeing.

7:55

And then finally, history and physical.

7:58

I really talk to the parents and family.

7:59

You can see where the scar was, where the injury was,

8:03

find out what they've done, if it's getting better

8:05

or worse in the interval.

8:06

It really helps you assess your pretest

8:08

probability for the exam.

8:10

And of course it's low cost compared

8:11

to other tests, but it is operated.

8:14

Dependent does require a high skill by the stenographers

8:17

and the radiologists for the image

8:18

acquisition and interpretation.

8:21

You are seeing kind of the trees, not the forest.

8:22

We're very zoomed in.

8:24

Uh, we may kind of not really understand

8:26

that there's more global injury muscle denervation changes,

8:30

which is typical when you have a nerve injury.

8:32

They're kind of easier to see on MRI.

8:34

You see the very high signal for the denervation.

8:38

And we're not only, we're not really gonna see deeper.

8:40

So if there's something in the bone, uh,

8:43

we really only just see the surface.

8:45

We're limited to superficial structures.

8:49

So that was this the um, initial, um,

8:52

discussion of the anatomy.

8:54

First we're gonna go upper extremity nerves

8:56

and then we're gonna go lower extremity nerves.

8:58

So you may ask, well what nerves do I need to know?

9:02

Um, in the upper extremity there's the kind

9:06

of the main peripheral nerves.

9:07

There's course gonna be small little branches,

9:09

but I think um, when you are being asked

9:12

to scan these nerves, if you know these nerves,

9:16

then you're going to be able to

9:19

evaluate the majority of nerve cases.

9:22

So as you look at this drawing, um, you can see

9:25

that the yellow lines are nerves.

9:26

So you're gonna want to know the ulnar nerve,

9:29

which is gonna be medial.

9:31

It'll go through the cubital tunnel

9:33

and then down into the wrist at guy's canal,

9:37

the median nerve will sort of be in the middle

9:39

across the elbow.

9:41

And then as we showed, it's buried around muscles.

9:45

And then as you all know, it is in the carpal tunnel.

9:49

The radial nerve's a little trickier.

9:51

It comes along the lateral aspect of the elbow

9:55

and then it splits into two branches.

9:57

And this is important. So the posterior neuro osseous nerve

10:01

or the pin and the superficial radial nerve,

10:05

the posterior neuro OSUs nerve is your motor branch.

10:07

And the superficial radi nerve is more of a sensory branch.

10:11

So if you have someone with wrist drop,

10:13

you're gonna be thinking about the pin.

10:17

Let's go step by step of what these nerves look like

10:21

as we image it

10:22

and show you how to actually do these

10:24

protocols in real time.

10:29

This is an elbow of course,

10:31

and we're showing a transverse image of the radial nerve.

10:34

Notice how the probe is slightly along the lateral aspect.

10:36

And this is what the image actually looks like here.

10:39

You're gonna have the brachy radialis muscle

10:42

and you're gonna see in this little oblique course, uh, um,

10:47

o obliquely oriented crease,

10:48

you're gonna see the radial nerve

10:51

and you see tiny little sles here.

10:55

This is just the surface of the humerus.

10:57

Notice how you see the hypo coic articular cartilage

10:59

and the underlying cortex.

11:05

As you go slightly distal, you're going

11:08

to see it split into two nerves.

11:09

As we said, you have this superficial radial nerve

11:13

and the posterior interosseous nerve.

11:19

What you're gonna do for the posterior interosseous nerve is

11:22

you are going to flip the probe

11:28

and you have to do a slow little clockwise counterclockwise

11:31

motion to stay on it.

11:33

And you're gonna see that the posterior nerve,

11:35

interosseous nerve has a little bend to it

11:40

that is actually usually normal.

11:43

And this area with this hyper coic tissue is is known

11:46

as the arcade ros.

11:48

And what that is, is basically the superior edge

11:51

of the supinator muscle has a little fibrous area

11:54

and it's an area where the pin can get entrapped.

11:58

Um, and so we do look at that area when we're trying

12:01

to assess for pin syndrome

12:03

but realize there's gonna be a little bit

12:04

of a bend in the nerve normally, um,

12:07

as it crosses this area, if you had a true compression,

12:12

you would see upstream thickening of the nerve, um, as well,

12:16

which we do not see in this case.

12:22

Now let's look at the median nerve. Notice.

12:24

The probe is slightly more towards the

12:26

medial aspect of the arm.

12:28

You can see here it's right next to the arteries and veins

12:34

and the nerve is right here in the middle.

12:37

Remember, all nerves are gonna look the same.

12:38

They're gonna have these little hypo vesicles.

12:43

When we look at the median nerve at the wrist,

12:46

you're gonna see the nerve is just deep

12:48

to the flexor reticulum

12:51

and it looks different than the adjacent flexor tendons.

12:55

Notice how the tendons are more hyper coic

12:58

and the nerve is generally hypo coic.

13:03

In longitudinal, the nerve will have a little bit

13:06

of undulation, but you don't wanna see an actual focal pinch

13:10

or compression of the nerve.

13:12

And when you are in the adult role, evaluate

13:14

for a carpal tunnel syndrome, we're gonna be measuring the

13:17

cross-sectional area of the nerve in multiple places

13:20

to assess if it is enlarged or not.

13:25

Looking at the elbow, you're gonna want

13:28

to have the patient kind of turn their body

13:30

to the side a bit as shown in this picture.

13:32

And you really have to get posterior.

13:34

So it's posterior medial, you're gonna feel two bony bumps

13:37

as we all can feel on ourselves.

13:40

And one is gonna be the medial epicondyle

13:42

and the other is the eon.

13:43

If you put your transducer across those bony bumps like a

13:46

bridge, that is how you're going to find the cubital tunnel.

13:51

And within those two, uh, bony uh, humps here,

13:56

you're gonna find the ulnar nerve.

13:58

And you wanna see it in this groove, not dislocated outwards

14:06

in longitudinal of the ulnar nerve.

14:07

You're gonna see the nerve has a little bit

14:09

of an undulation, but that's okay.

14:10

You don't wanna see any focal pinch or upstream thickening.

14:17

As we go to the wrist, you can see

14:20

that the ulnar nerve is adjacent to the ulnar artery

14:24

and it is in a small little tunnel called ion's canal.

14:33

Now how do we do the ulnar nerve subluxation?

14:35

This is a common request

14:37

and you can incorporate it into your protocol.

14:41

Um, it's not hard to do.

14:43

Um, it's just nice to have that information for the surgeon.

14:46

Is it subluxing out or not?

14:49

So you're going to want to put, put your probe again in

14:51

that starting position with the patient in extension.

14:55

The tricky part is keeping the probe in place.

14:58

As the patient is flexing up this,

15:01

the nerve will subluxate out of the groove

15:03

at the max flexion.

15:06

This takes a little practice, but this is how you'll do it.

15:09

Here's what it looks like. The patient is slowly flexing up.

15:13

If you look at the nerve right here, you're gonna see

15:18

as they get to max flexion, the nerve

15:21

is abnormally going over the medial epicondyle

15:25

and popping over to the anterior tissues there.

15:32

So one trick is to say when you're doing the dynamics,

15:36

just put the probe right over the medial peon dial,

15:38

forget about the reon,

15:40

put the probe right over the medial epicondyle

15:42

'cause that's what you're focusing on

15:44

and you wanna see if the nerve pops out.

15:45

Sometimes it'll sort of perch and go halfway,

15:47

but you can see here pops over.

15:50

So this is on a nerve subluxation.

15:55

So those were the upper extremity nerves.

15:57

Now I'm gonna pause here

15:58

and talk a little bit about nerve injury.

16:01

Very commonly you're gonna get a request for evaluation

16:04

of nerve injury and you need to have something

16:06

to say about it and need to know what you're looking for.

16:09

So first of all, in your mind you can separate nerve injury

16:12

into low grade and high grade.

16:14

So a low grade nerve injury is often non-operative, right?

16:19

So it might heal on its own.

16:22

Um, it will take a long time,

16:23

but they don't necessarily need to brush in and do surgery.

16:26

High grade nerve injury will often require surgery

16:30

and there are improved outcomes

16:32

with early surgical intervention.

16:37

EMG um, is a good test

16:39

but it can take months for the downstream effects to appear.

16:43

Um, so if you have a nerve injury

16:45

that is innervating a particular muscle, they're gonna test

16:48

that muscle to see if the muscle is becoming denervated.

16:53

Um, as a sign that there was an upstream nerve injury,

16:55

it's an indirect evaluation.

16:57

However, the test has a difficult time identifying the exact

17:01

site of nerve injury.

17:03

It can get, uh, around the area.

17:05

But with anatomic imaging we can help them localize the

17:09

exact site of the injury.

17:11

That's what's so powerful about ultrasound.

17:13

They also will do nerve conduction studies typically at the

17:16

same time as EMG and they're gonna test the electrical

17:19

activity across a particular area segment of nerve.

17:23

So some of the issues with that is

17:24

that if you have a severe stretch injury nerve is kind

17:28

of stunned and the nerve conduction can actually look like

17:32

there's no electrical activity.

17:34

And so you might have a false, um, interpretation

17:37

that the nerve is transected

17:38

or cut completely when in fact the nerve is intact.

17:42

It just is stunned in a severe stretch

17:46

and ultrasound's able to tell if it's

17:47

intact, uh, very easily.

17:50

And we know that failure to repair the nerve

17:52

beyond six months will result in poor recovery

17:56

and permanent neurologic deficits.

17:57

We want to get to the injury as quickly as possible

18:02

and children luckily have a greater spontaneous recovery

18:05

of low grade injury.

18:06

With medical management there are times

18:08

where a surgeon might want to go in there

18:10

and do a neurolysis and clean up the nerve.

18:12

There's some scar tissue, but in general, um,

18:15

low grade nerve injuries can be treated non-operatively.

18:19

So what is our goal as the radiologist?

18:23

We get a patient with a nerve injury, we want to number one,

18:26

localize the site of the injury.

18:29

So they may know that they had a fracture of the arm,

18:31

an elbow fracture, a form fracture,

18:33

they may have some tingling, some weakness,

18:35

but they don't know exactly where the nerve injury is.

18:37

So you want to tell 'em exactly where it is.

18:41

We want to distinguish between low

18:42

and high grade nerve injury.

18:48

So there are a few nerve injury classification systems

18:52

and I've created a little table here to help kind

18:55

of blend them together, um,

18:57

and try to make it practical of what you might see.

19:01

So the seeding

19:02

and the sunderland classifications is sort of a

19:05

clinical pathologic uh, classification system

19:08

that you will hear clinicians use.

19:10

The seeding classification is a three, uh, part, um,

19:15

grading system with neuropraxia being mild emesis moderate,

19:19

and neuro is is severe.

19:21

Sunderland breaks it out into five categories

19:24

and if you were gonna try to blend them together,

19:27

neuropraxia would be similar to a sunderland one.

19:30

Axon ESIS is two through four

19:32

and neurosis would be as similar to a Sunderland five.

19:35

But let's look at this chart right here

19:37

and try to make it even simpler.

19:40

If you combine the Sunderland edin, you basically have

19:43

a low grade category, which would be a one through three.

19:47

So if you're a sunderland one through three,

19:48

we're gonna call it low grade.

19:50

What will you see on the ultrasound?

19:51

You're gonna see a normal or a thickened nerve.

19:54

Usually this would be non-operative management.

19:56

So it's very important to diagnose a low grade injury.

20:00

Type four is a special category.

20:03

So once you in type four you're high grade,

20:06

but on ultrasound this correlates

20:08

with a neuroma in

20:10

continuity and we'll talk about what that is.

20:12

That is typically an operative intervention that is needed.

20:14

Neuroma in continuity is basically a scar ball of the nerve.

20:17

So you're gonna see a nodule, you're not, you're gonna lose

20:20

that kind of smooth uh, course of the nerve.

20:23

It's gonna look like a little mass in the nerve

20:28

ESIS or number five is gonna be also a high grade injury

20:31

of course, and that's a complete transection of the nerve,

20:33

totally cut nerve and obviously that would need operation.

20:37

So you can see here that the main management, um, kind

20:41

of landmark is going from a low grade to a high grade.

20:45

So we're gonna be looking for findings of high grade injury,

20:47

a neuroma and a transection.

20:51

Let's go through multiple examples.

20:53

Now here would be a low-grade injury.

20:55

A 14-year-old female softball player

20:57

with is ulnar sided posterior elbow pain for two weeks.

21:00

And you can see the nerve is just a little bit thicker.

21:03

Where're losing that nice vesicular architecture

21:06

where you see multiple kind of alternating hypo coic,

21:10

hyper coic just looks a little bit swollen.

21:13

So that would be a low grade nerve injury.

21:17

Let's go into the high grade nerve injury.

21:19

Here's a schematic from the literature.

21:20

You can see that a type four

21:22

or a aroma in continuity is gonna see a scar ball

21:26

or a big kind of nodular blob within the nerve.

21:30

But notice it says in continuity the nerve is still intact.

21:35

Whereas in a transection

21:37

or Sunderland five you may have a neuroma

21:40

but it's not in continuity

21:41

and the neuro typically is along the proximal stump.

21:44

But you're gonna have a gap in the nerve

21:46

and you need to detect that.

21:47

So this stump neuroma has a few different names,

21:50

terminal neuroma and bulb neuroma.

21:54

And you're going to see a gap.

21:55

Both of these are high grade nerve injuries.

21:59

So what will this look like? Here's an example of a patient

22:03

who had a medial forearm laceration.

22:05

Very commonly, this is a scenario.

22:07

You have a laceration of the forearm,

22:08

the upper extremity nerves are vulnerable.

22:11

It is treated at the outside hospital with stitches.

22:13

This is unfortunately often the presentation.

22:16

You know, you you treat the acute injury.

22:19

Uh, you, you, you, you sew it up.

22:21

But the nerve injury may have gone um,

22:24

unrecognized at the time

22:27

the patient presented six months later

22:28

with ulnar distribution sensory and motor nerve deficits.

22:32

And what you can see here, the nerve looks normal

22:35

to screen left, little nice alternating hypo

22:37

coic, hyper coic fassal.

22:39

But then look at this segment here between the plus sign,

22:43

you can see here it's hypoechoic thickened.

22:46

We're not able to see those typical fales, right?

22:50

So you have a nodule, you have continuity of the nerve.

22:54

So we call it a neuroma in continuity.

22:57

And this is a solen four high grade nerve injury.

23:00

You've done your job. This was a very interesting patient

23:03

showing you the power of ultrasound over MRI.

23:05

In this particular case, the patient had a history

23:08

of fracture, dislocation of the elbow.

23:10

They fixed the

23:13

elbow fracture in the acute setting, you see the hardware there.

23:17

But the nerve was actually displaced into the

23:20

joint at the time of injury.

23:21

It was a very severe injury.

23:23

Nerve got trapped in the joint,

23:24

they took the nerve outta the joint, they fixed the bone

23:27

but presented to neurosurgery clinic three months later

23:29

with persistent motor and sensory loss of the ulnar nerve.

23:33

They ordered the MRI

23:34

'cause that's what we typically used to do

23:36

and you can see here tons of artifact, very hard

23:38

to see the nerve to see what's going on.

23:40

So we recommended ultrasound

23:44

and what you're seeing here, we have a comparison

23:46

of the normal side showing you the the advantage of

23:49

of comparing to normal side versus the abnormal.

23:52

Notice how in the abnormal side these fascicles look normal

23:55

but this one is incredibly enlarged

23:58

way outta proportion to the other ones.

24:01

So this should catch your eye.

24:02

This fascicle is much larger than the other ones,

24:05

it's heterogeneous, whereas on this side the nerve had more

24:09

of a uniform testicular pattern.

24:12

So this ended up being a neuroma in continuity

24:15

and ultrasound was very helpful, not as impeded by the uh,

24:18

metallic hardware.

24:21

Here's patient with a high grade nerve injury.

24:25

This was a soccer injury, patient came for ultrasound.

24:28

You can see here the nerve is very enlarged,

24:32

vocally swollen, heterogeneous, you can't make out any fales

24:37

but it's still in continuity.

24:38

So this would be a neuroma in continuity.

24:41

You tell 'em it's a high grade nerve injury,

24:43

then they're probably going to have to operate.

24:48

This was a patient who um, actually

24:51

had a nerve uh, injury and a repair.

24:56

Um, and so we're asked to do the postoperative uh,

24:59

evaluation and what you can see here, there's some uh,

25:03

hyper coic sutures.

25:04

The nerve is coming down

25:06

but at the site of the surgical repair,

25:09

very enlarged heterogeneous nodule,

25:13

big scar ball in the nerve, neuroma in continuity.

25:16

And this is a type four high grade

25:19

nerve injury after repair.

25:22

How about the worst case scenario?

25:24

So this is when the nerve is completely lacerated.

25:29

This patient had a severe laceration of the upper arm

25:32

and injured multiple nerves and vessels.

25:35

What we're seeing here in image A is we are

25:39

tracing the median nerve down.

25:41

We see a stump neuroma

25:43

but then we'd see no neural tissue after that.

25:46

This is a complete gap

25:49

and you see nerve fibers here in the distal part.

25:53

So this is a complete laceration.

25:57

In number B, we're looking at

25:59

a different nerve, the ulnar nerve.

26:01

So here's a surgical clip that you're seeing here.

26:03

When they replaced the vessel,

26:05

this is the ulnar nerve coming down

26:08

and then we have a gap, no neural tissue in this gap

26:13

and then the distal stump.

26:14

So there's two nerves, two complete transections.

26:18

And by telling them exactly where it was, they knew that

26:22

where to go and they knew that they could get to it earlier.

26:24

This patient was on the schedule for an EMG, had

26:27

to wait like a few months to get to see EMG,

26:30

but we were able to show them it's completely gone.

26:32

Don't even bother with the EMG, they got to the OR sooner.

26:37

Here is a patient with a stab wound to the forearm

26:40

and presented with a wrist drop.

26:42

So couldn't extend the wrist.

26:43

So you have to think this is radial nerve distribution.

26:46

You look at the radial nerve, you trace it down, you go

26:49

to the posterior interosseous nerve, look what happens.

26:53

Nerve is in blue, right

26:56

where you have the transection, you just see fluid.

26:59

This gap stump of the nerve here and the distal nerve.

27:04

When you go and transverse, instead of seeing two nerves,

27:07

you're seeing just a fluid gap where the pin should be.

27:10

So this being a complete laceration

27:13

of the post generos is nerve.

27:17

This is a five-year-old who lacerated his

27:19

wrist against a window.

27:21

And what you're seeing here is

27:23

that you follow the nerve down

27:24

and all of a sudden you see a stump neuroma, right

27:27

big hypo nodule

27:29

and look how there's just a gap, complete gap,

27:32

no neural tissue at all.

27:33

And then the distal nerve is reflected

27:35

into the superficial tissues.

27:37

So again, Sunland five high grade nerve injury.

27:40

Complete laceration. This patient had an ulnar

27:45

nerve, uh, and had an ulnar nerve repair

27:48

but was lost to follow up.

27:49

And you can see here it came back with a claw sign.

27:52

So we know the claw sign, we're thinking

27:54

of ulnar nerve issues.

27:57

We look at the ultrasound

27:59

or the the the MR at the elbow on a sagittal image,

28:02

the nerve is coming down and all

28:03

of a sudden you see a big ball here,

28:06

big neuroma, nothing after it.

28:08

On transverse you see a neuroma here.

28:10

Patient also had injury to um, the median nerve.

28:14

Here it is an ultrasound nerve coming down fales here

28:18

and all of a sudden you get into this area that has no sles,

28:20

just a big mass heterogeneous mass blind ending.

28:24

Nothing beyond this.

28:25

So this was a complete rupture of the prior repair.

28:30

A dehiscence,

28:36

This patient had a gunshot wound.

28:39

We have a big bullet fragment at the elbow

28:42

and obvious humerus fracture.

28:45

Patient has a wrist drop so you're thinking

28:48

radial nerve can't get an MRI gonna be artifact

28:52

and may not be safe.

28:55

Let's do an ultrasound.

28:57

We're looking in longitudinal nerve coming down.

29:00

You see the humeral shaft below it, the nerve just kind

29:03

of peters out and you see here just a stump.

29:07

It's going into the fracture cleft and terminating blindly.

29:12

And we went searching for the nerve distally,

29:14

found the distal stump somewhere, um, in a different area.

29:17

So this was a complete transection of the radial nerve

29:21

and it was just nice because you can't do the MRI

29:25

but the ultrasound, you really can figure out what's going

29:27

on if you trace the nerve.

29:32

This case is a rare complication of an of a fracture.

29:36

So you have a both bone form fracture,

29:38

very common in pediatrics.

29:40

And this patient, they kept following the x-ray

29:43

and just kept seeing the fracture.

29:45

Cleft never really went away wondering what's going on.

29:48

On exam. The patient had some muscle wasting along the

29:51

thinner aspect of the hand

29:54

and they thought this is not normal.

29:56

We gotta figure out what is going on with this median nerve.

30:00

So let's do an ultrasound.

30:02

This is the nerve here and I'm gonna play you a video.

30:05

The nerve is right adjacent to the bone.

30:08

So let's see what happened to the median nerve.

30:14

As you're tracing the nerve down, notice

30:17

how it very abnormally goes into the bone.

30:20

So it literally is entrapped

30:24

in the fracture site.

30:28

And so basically the bone healed over the nerve

30:32

and ultrasound was very powerful to diagnose

30:35

that on MRI you can see the nerve coming down pinched,

30:39

stuck in the bone and here on transverse going into

30:44

the bone, this patient actually did well.

30:46

Uh, they went to the OR there was a small little shell

30:49

of bone, they unroofed it released the nerve

30:52

and the nerve was actually still okay,

30:55

but this was a very nice case.

30:57

So ultrasound showing a nerve entrapped in bone.

31:03

Here's another example of ultrasound, uh,

31:05

that really can help you localize an injury.

31:09

This is a very unfortunate patient, a teenager

31:11

who had multiple stab wounds to the arm.

31:14

Uh, and so literally when you looked at the arm there were

31:17

multiple uh, lacerations all up and down the arm.

31:22

So of course the patient had um,

31:26

a nerve issue they had, they had a wrist drop.

31:28

Um, but wrist drop just tells you that it's radial nerve

31:32

but you don't know where so you can't do a surgery

31:34

of the entire arm, right?

31:36

So I went in there with the plastic surgeon

31:39

and we just started from the top.

31:40

I just trace the nerve down

31:42

and tried to see where is the site of discontinuity.

31:46

And what we found is in the upper arm

31:49

before it had actually um, bifurcated,

31:53

you can see the nerve coming down

31:56

and literally just uh, lacerated,

31:59

you can see the end of the nerve.

32:00

This is the fluid gap where the uh, laceration um, occurred.

32:05

This is the gap and you can see the nerve distally to it.

32:11

So we actually just marked the skin in the ultrasound room

32:15

and they took her straight to the OR and

32:17

because it was so soon

32:18

after the injury, they were able to repair the nerve.

32:20

So I have a gross picture coming up.

32:21

So if you're squeamish close your eyes for the next slide.

32:25

But basically it predicted the injury exactly.

32:30

So here's the nerve coming down,

32:32

you see a complete laceration right

32:34

where we saw an ultrasound and this is after the repair.

32:38

So they did a primary primary repair of the nerve

32:41

so they were able to know exactly where the injury was.

32:44

You can see this is another LA laceration site

32:46

that was not the site of the nerve injury.

32:50

Okay, take a deep breath

32:52

and we are gonna go onto lower extremity nerves.

32:57

So what nerves do I need to know?

33:02

You need to know the sciatic nerve is the biggest nerve

33:05

and you need to know how to trace it in the posterior thigh.

33:08

As you get to the knee, you're gonna see

33:12

a bifurcation.

33:14

So you're gonna see the perineal nerve

33:17

and the tibial nerve.

33:21

The perineal nerve is known as the common perineal nerve

33:24

as it bifurcates off of the sciatic nerve

33:28

and it will wrap around the fibular head

33:30

and then split yet again into the deep perineal nerve

33:34

and the superficial perineal nerve

33:36

analogous to the radial nerve.

33:37

Similarly. So the deep branch is going to be more

33:41

of a motor branch and the superficial is more of a sensory.

33:47

The tibial nerve will go directly down past this area known

33:52

as the sole sling and it'll work its way medial to get

33:55

to the tarsal tunnel.

34:00

Okay, so let's do the exam and figure out how to do it.

34:03

First you're gonna put your probe patient is lying prone.

34:06

You're gonna put your probe in transverse back

34:08

of the distal thigh and you're gonna see the nerve.

34:11

At first it can be kind of a little bit hard to see

34:12

because you have um, fatty tissue muscles.

34:15

It's kind of deep in there so you have to kind

34:18

of get used to seeing it.

34:20

Um, in the back of the thigh when you go in longitudinal,

34:23

you're gonna see the alternating sles, hypo coic

34:26

and hyper coic

34:26

tissue at the bifurcation.

34:32

As you can see by this blue mark here, you're going

34:34

to see the tibial nerve and the CPN.

34:38

Now the CPN is going

34:42

to be going diagonally toward the lateral aspect of the leg.

34:46

So you're going to alter your probe position

34:49

and now you see the CPN coming down here, see

34:52

where your probe is on the patient.

34:58

Now we're gonna go and transverse yet again

35:00

and we're gonna see that that actually

35:02

splits into the deep branch

35:04

and the superficial perineal nerve.

35:06

When it is splitting,

35:07

typically the deep branch will be the anterior one

35:09

and it'll wrap around first, um, around the bone

35:13

and the superficial will go behind it

35:17

at the tarsal tunnel.

35:19

Remember the mnemonic to dick and nervous hairy.

35:23

So the tibial nerve is going

35:25

to be here in the tarsal tunnel.

35:34

What about the superficial perineal nerve?

35:36

Much smaller nerve harder to see,

35:38

but at the ankle there's a few landmarks

35:41

that can really help you find it.

35:44

If you find the fibula,

35:46

the fibula will have a little bony point here

35:49

and it typically is just superficial to the fibula.

35:52

So I usually find the bony, um, apex of the fibula

35:57

and you'll see the superficial perineal nerve

35:59

right in that area.

36:02

Here it is in longitudinal very small nerve.

36:09

So with that in mind, let's think of

36:11

what to do about this case.

36:13

And this is again showing you a nice advantage

36:16

of ultrasound sound.

36:18

This was a patient, um, that

36:22

was undergoing a uh, leg length procedure.

36:27

Um, and um, they actually, um, had

36:32

to put an x fix, um, after the procedure.

36:34

And so in order to put the X fix in, they have to fixate it

36:39

superiorly and inferiorly on the superior part, they have

36:42

to put screws in the tibia and fibula.

36:45

And so the surgeon called

36:47

and said when they were putting in the the bone, it kind

36:50

of skived off the bone and there was some immediate

36:52

fasciculations of the foot

36:53

and they were nervous that they injured the uh, the nerve.

36:57

After the surgery, the patient woke up

37:00

and had a foot drop immediately.

37:02

So they were terrified. Did they transect the

37:03

nerve, what can we do?

37:04

But they already had the X fixx on.

37:07

So they asked can we do an MRI, an MRI, you may be able

37:12

to do it, but there's so much artifact, very small leg,

37:16

very small nerve, really difficult.

37:19

So I said let's try to do an ultrasound.

37:22

So here is the x fix,

37:25

it's actually in the patient, uh, connected.

37:28

So they allowed us to take the bandages off

37:31

and I took the little tiny hockey stick probe

37:34

'cause you couldn't even physically fit a

37:35

regular probe underneath this.

37:38

And I went to where I think that the um, perineal nerve is.

37:42

And what you can see here is that the deep branch

37:45

of the perineal nerve is very thickened.

37:49

However, you can all see that it's not transected.

37:52

So I told the surgeon, um, the nerve is intact,

37:56

it's thickened, so it may be a little bit swollen.

38:00

No immediate surgery needed to remove the X fixx.

38:03

And the patient slowly improved over the course of time.

38:07

So it was very powerful to be able

38:09

to tell them it's not transected.

38:11

And so that's the power of ultrasound about

38:15

some high grade injuries.

38:16

And we show this picture again, we're looking

38:18

for aroma in continuity and complete transection.

38:23

This was a 12-year-old patient

38:25

who had a gunshot wound 11 months prior.

38:30

The patient presented with a foot drop and numbness.

38:33

We start scanning the sciatic nerve, we trace it down.

38:36

As you can see the nerve is a little bit thickened

38:40

but relatively normal proximal.

38:42

And then we get into this large mass.

38:43

In fact, the sonographer came to me

38:45

and said there's a tumor of the sciatic nerve

38:49

and at first glance it does look like a tumor,

38:51

but you go to the history and you say, okay,

38:54

this is actually a huge neuroma in continuity

38:58

of the sciatic nerve.

39:00

So high grade injury, big scar ball, big neuroma,

39:03

but nerve is still continuous here it is in

39:07

transverse as well.

39:13

Patient had a foot deformity surgery.

39:15

This is a different patient. This is just an

39:18

incidental little vein in the picture.

39:19

So ignore that. We're following a little tiny

39:22

nerve branch in the foot.

39:24

You can see nerve, nerve, nerve and then nodule.

39:27

So this was a high grade neuroma in continuity

39:32

and this was a branch of the sal nerve.

39:34

This patient had a tri plaine fracture,

39:36

very common in pediatrics.

39:38

They put a transverse screw through the epiphysis,

39:41

but there was some pain and numbness in the lateral ankle.

39:44

Patient had a little nodule on exam in fact too.

39:47

We looked right over the area laterally

39:50

and following the superficial branch

39:52

of the perineal nerve down, all

39:53

of a sudden you see focal bulbus and enlargement

39:57

and we didn't see any neural tissue distal to this point.

39:59

This was a complete transection of the SPN

40:02

and an end bulb neuroma.

40:04

So sun in five complete transection as we went distally,

40:09

you can see there's a scar tissue.

40:10

There was no neural tissue in the gap.

40:12

This was a complete, uh, transection of the nerve.

40:17

Patient actually had the nerve had this nerve repaired

40:19

and unfortunately three years went by

40:22

and um, had new pain scanned.

40:26

Again, you can see the nerve coming in.

40:28

And another neuroma had formed this time

40:30

neuroma in continuity.

40:32

And you can see here some normal neuro fibers,

40:35

big heterogeneous neuroma

40:36

and some neuro neuro fibers exiting the

40:39

neuroma sunderland four.

40:41

This time this was a 13-year-old

40:45

with laceration of the leg.

40:48

We are looking right over the area

40:49

and we find the superficial perineal nerve coming down.

40:54

Stump neuroma, focal nodule, no neurot,

40:57

distal sunland five.

41:01

This patient, uh, was a patient who's had a prior amputation

41:04

for, for another reason and came in

41:07

and um, was diagnosed with multiple masses.

41:11

We see hypo coic masses

41:12

and we kind of wonder, okay, that's unusual,

41:16

let's go in longitudinal.

41:18

And we say, wait a minute, these aren't masses.

41:20

These are actually just stump neuromas.

41:23

So just remember that when you do a tra uh, an amputation,

41:27

you're going to intentionally cut the nerve

41:29

and stuff it into tissue.

41:31

Um, and you can unfortunately get these stump neuromas

41:35

that can be problematic.

41:36

But these were blind ending things

41:38

and so these were stump

41:39

neuromas and they actually can enhance.

41:40

And I've seen a few cases where they are mistaken

41:43

for sarcoma recurrences and whatnot.

41:45

So remember that stump neuromas are common

41:48

and they can enhance and they're going

41:50

to be blind ending, uh, neuromas.

41:53

And just a little bit about intraoperative consultation.

41:57

Um, these are, this is me wearing a bunny suit

42:00

and two of my colleagues in

42:01

neurosurgery and plastic surgery.

42:03

I will be asked to come to the operating room, um,

42:06

and I will gladly go up there

42:08

and they like to scan over the neuroma

42:11

and the transection at the time of the surgery

42:13

to help limit the incision

42:14

and to know exactly where the nerve injury is

42:16

at the day of the surgery.

42:19

So, um, here's just an example.

42:21

This was a patient who had an emerging inguinal LVAD placed,

42:25

uh, was a pre heart trans.

42:27

Um, so they had to get access. Um, it had weakness.

42:30

They did an MRI, we see the femoral nerve coming down.

42:33

It was kind of hard to see what was going on.

42:35

The nerve looked a little bit thickened,

42:37

but then it was all the scar tissue

42:39

and we didn't know what was going on.

42:42

Go to the or. This is an intraoperative all ultrasound.

42:45

You can see the gel, the open field,

42:47

and you can see the nerve coming down

42:49

the femoral nerve or a branch of it.

42:51

And a staple was actually unfortunately stapled into the

42:54

nerve in the, uh, in the, the chaos of the emergent,

42:58

uh, LVAD placement.

43:00

And so we showed the nerve and the, and the,

43:02

and the staple was shadowing there, removed the staple.

43:04

The nerve actually was okay, they did some re minor repairs.

43:09

Here's another case of a patient who was a little baby

43:12

with a fibrous sarcoma.

43:14

And after the neoadjuvant chemotherapy,

43:17

the tumor had shrunk in so

43:18

much they couldn't even feel the tumor.

43:20

So I went to the or.

43:21

Um, we found the tumor showed how close it was

43:24

to the neurovascular bundle,

43:26

showing you here the tibial artery and the tibial nerve

43:30

and that there was a small little fat plane there.

43:32

They removed the tumor

43:34

and I was able to show the surgeon at the time

43:36

of the surgery that the artery and veins were still intact

43:40

and everything was all good.

43:42

So here is the gap, uh, the, the the resection bed.

43:48

So in conclusion, ultrasound is excellent

43:51

for peripheral nerve evaluation.

43:52

It is a non sedated, non-contrast exam.

43:55

It is helpful over MRI if orthopedic hardware is present.

43:58

Really good for small nerves

44:00

and really nice for collaborative opportunities.

44:05

Thank you guys so much for listening.

44:07

I hope that was educational.

44:09

And now I'm going to, um, open it up

44:12

for questions from the group.

44:15

Thank you for sharing your lecture with us today.

44:17

Of course, Dr. Uh, Sam At this time we will open the floor

44:21

for any questions from our audience.

44:24

Remember you can submit your questions

44:26

through the q and a feature.

44:28

Okay? Um,

44:30

and what we're gonna do is, let's see here

44:33

from anonymous attendee how

44:35

to distinguish post-surgery healing

44:37

and hence focal bulging of the nerve from neuroma.

44:44

So, um, yes, I think what the question is getting at is

44:49

if you have enlargement of some fales,

44:53

but it's not truly a neuroma, how do you distinguish?

44:56

And sometimes it is hard if I feel like I lose the

45:00

fascicular architecture, meaning

45:03

I can't follow a hypo coic line, it's starting

45:07

to look heterogeneous.

45:09

Um, it looks bulbous.

45:11

That's when I will say, um,

45:13

this could be an aroma in continuity.

45:15

And sometimes you're right, you can't totally tell

45:18

if you're dealing with an aroma or not,

45:20

but usually it is, it, it's, it's,

45:22

it's pretty clear if you have an aroma, uh,

45:24

do you always give contrast neurography?

45:26

So you're gonna get different answers on the pediatric side,

45:29

no, on the adult side, they do like it.

45:32

Um, we did a paper, um,

45:35

a few years ago in skeletal radiology showing that, um,

45:40

in fact contrast didn't necessarily add that much

45:43

for m MRI neurography.

45:44

Um, as we said,

45:46

neuromas can enhance, so sometimes it can help you.

45:48

But I find that the T two hyperintense, uh,

45:51

nerve is visible just without contrast.

45:54

Um, from angelard. Hello, Dr.

45:58

Sam, do you use microvascular color flow imaging?

46:00

I find it very useful. Um,

46:04

I don't necessarily, I think you're right.

46:06

It is useful for arthritis imaging.

46:08

Um, for me, hyper vascularity the nerve is not

46:12

necessarily, um, that helpful.

46:14

I'm really just looking at is there an intact nerve,

46:16

thickened nerve, um, and or, or a transection or neuroma.

46:22

Um, let's see here. Hello, I'm Dr.

46:27

Mohammed Sadik, BA from Pakistan.

46:29

Sir, can you show the images

46:30

according to what you were describing?

46:32

Thanks in advance for your, for your sponsor cooperation.

46:35

Um, I think that might have been an older question.

46:39

Um, and we hopefully we answered

46:40

your question by showing images.

46:41

Images not shown. Only picture presenter. Okay.

46:43

Hopefully you guys were able to see my talk.

46:47

Uh, another question.

46:48

Do you prefer T two SIR PD fat set

46:50

or T two weighted fat set sequence?

46:52

So, um, that's a good question.

46:55

Uh, I think depends on the scanner that you have.

46:58

Um, we typically will do, uh,

47:02

like an axial T two fat set.

47:04

We'll do some stir imaging. I like the coronal stir space.

47:07

If you have Siemens stir space is like that 3D sequence

47:11

where it can give you, uh, then multiple reformats.

47:14

Some people use T two spare,

47:16

some people like the death sequence.

47:18

Um, whatever gives you really good fat suppression

47:22

and really robust fat suppression.

47:24

It's very difficult

47:25

to evaluate MR neuropathy if you have poor fat suppression.

47:28

So if you are going to have bad fat suppression,

47:32

then you're gonna, you're going to

47:34

think a nervous hyperintense when it's not.

47:36

So whatever gives you really good fat suppression.

47:38

How to distinguish lipoma from neuroma?

47:41

Um, that's pretty, pretty easy.

47:42

So basically lipoma is gonna follow fat

47:44

signal in all sequences.

47:45

So it's gonna be hyper intense on T one high po intense on T

47:48

one fat sat, whereas an aroma

47:50

should never have any fat in it.

47:52

Uh, Rahim Khan, can we use, uh, can ultrasound be used

47:56

during spine surgery?

47:57

'cause having hardware in the spine very difficult

47:59

to use MRI or artifacts.

48:01

Um, so, um, the problem is

48:05

for spine is that, uh, seeing the spinal cord, right,

48:10

and I, I don't know, I haven't used that to be able

48:12

to see the spinal cord.

48:13

You'd have to have a totally open posterior elements, uh,

48:17

before they put in that.

48:18

Um, I'm not sure that that we can do that.

48:21

Um, does this require to change the ultrasound pro

48:25

for vascular evaluation

48:26

and the same thing while doing

48:27

ultrasound for nerve evaluation?

48:29

Um, so it's typically a different exam for us.

48:33

Um, when you do vascular work,

48:35

you are basically just seeing if the nerve, if the,

48:38

if the vessels are open, um, and,

48:41

and it's totally kind of a different evaluation,

48:43

you theoretically could do it in the same thing.

48:45

But ultrasound, sonographers kind

48:47

of it's just get stressed out.

48:48

It's better just to have them as separate things

48:50

and they're usually coming from different providers.

48:52

You have a nerve, you'll usually have a nerve surgeon, uh,

48:55

that's looking to evaluate the nerves

48:57

and usually have a different provider that's,

48:59

that's evaluating uh, the, the vessels.

49:02

Good. Um, uh, there might be a couple

49:05

of questions in the chat if you didn't need those already.

49:08

Alright, let's see the chat.

49:10

Alright, um, what

49:16

pulse sequence lay up the nerves as you showed?

49:19

I think just, um, for MRI, uh, I think you're referring

49:22

to MRI again, um, T two fat suppressed sequences

49:27

that have really good uniform fat

49:29

suppression, I think is the most important.

49:31

Um, how useful is color doppler to check for neuritis?

49:36

Personally, I don't necessarily think it's that helpful

49:41

unless, you know, you see something like

49:44

extremely hypervascular.

49:45

I I think the, the power

49:46

of ultrasound really is the morphology of the nerve.

49:51

Um, so that does it

49:54

for the, the chat.

49:57

Yeah. And so I think, um, really the,

50:02

the ultrasound is, is good to start take, get familiar

50:06

with the anatomy of, um, of, of the nerves

50:09

as they course through the extremity.

50:11

Um, and trying to answer the clinical question for the,

50:15

um, for the provider.

50:18

Try to get them to tell you which nerves they're looking for

50:20

and um, if you go to the

50:22

or with them, they'll be very appreciative for you telling,

50:25

showing them exactly where the injury is.

50:29

All right. Well it looks like

50:30

we're, looks like that's that.

50:32

Thank you for your lecture today, Dr. Ed.

50:36

Thank you everyone. Um, and I hear another question.

50:39

One last question. Do you perform hydro dissection?

50:41

Um, so, um, I personally, uh, uh, do not,

50:46

haven't been really asked to do that.

50:48

I know that, um, obviously, um, if you're an IR

50:52

and doing procedures, you might want to, um,

50:56

push the nerve away.

50:57

Uh, for example, um, if, if you're trying

51:00

to do something like a biopsy or whatnot,

51:02

the surgeons are gonna be doing neurolysis, uh, themselves.

51:06

Um, so, so I don't necessarily do that.

51:08

I have done kind of nerve blocks where you basically kind

51:11

of just inject, um, around a nerve, uh,

51:14

but not, not personally done a specific hydro dissection.

51:17

Uh, uh, another question.

51:19

What is your experience with exploring the satic nerve in

51:21

the deep gluteal region?

51:24

So, uh, the sciatic nerve.

51:26

Um, yeah, when you start, uh, scanning higher

51:28

and higher, it becomes a lot harder

51:30

and you really need to push, uh, very hard to see it.

51:33

You can see it higher than you think actually.

51:36

And I've actually been able to see it over the buttock.

51:38

Um, we do get requests for, uh,

51:43

evaluation of the static nerve in the region

51:45

of the piriformis, uh, for piriformis syndrome

51:48

and we try to do dynamics more on the adult side.

51:51

I haven't found it that helpful to be honest.

51:53

Um, but you, you can see, uh,

51:57

higher than than you would think. Yeah.

52:00

All right. Well thank you

52:01

again. Great. Well you all for your lecture

52:03

Yes. So sorry.

52:04

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52:06

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52:08

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52:10

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52:12

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52:15

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52:27

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52:32

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