0:00

This case I know very well.

0:02

I interviewed the patient myself.

0:05

This is the wife of a, um,

0:07

chief financial officer.

0:09

Um, she's a mom.

0:12

She had, um, some plantar fasciitis and

0:19

they thought she might have some tarsal

0:21

tunnel syndrome initially, and they did a

0:26

tarsal tunnel release and allegedly did

0:30

some plantar fascial surgery at a very

0:32

esteemed institution, Duke University in North

0:36

Carolina, and she is now permanently disabled.

0:44

So let's see what happened.

0:45

Once again, we're putting up our

0:47

water-weighted sagittal images.

0:49

Actually, we'll put up all our

0:51

sagittal images like we said we would.

0:53

A T1 on the right, a T2 in the middle,

0:57

A proton density fat suppression

0:59

on the left T's pretty good.

1:01

I like 40 but that's all right.

1:04

You have very good fat suppression.

1:05

Look how black the fat is and let's

1:07

scroll.

1:14

Now she's 50.

1:16

Why would a 50-year-old have

1:17

muscles that look like this?

1:22

Look at the gradient echo.

1:24

I'm sorry, look at the T2 stir, my

1:25

apology, the T2 stir. Look at the

1:27

demon, and the, and the musculature.

1:34

It's diffusely

1:34

edematous, yet it's atrophic.

1:41

Now,

1:42

let's look at another projection.

1:44

Let's take three short-axis projections.

1:47

There is one. There's two, there's three.

1:52

Remember, I did say the patient

1:53

is permanently disabled.

1:56

She cannot stand for more

1:58

than 10 seconds on her foot.

2:01

So she, you know, when she goes into a

2:03

grocery store, she has to have a cart.

2:06

She has to roll herself on a cart.

2:10

Let's blow them up.

2:11

So they all fit

2:12

in the windows very nicely.

2:18

Now you should all be struck

2:20

by the loss of muscularity.

2:23

You know, it's the simple, simple

2:25

things that we tend to overlook.

2:27

I mean, that really is going to tell

2:29

the story for you because there aren't

2:32

too many things in a 50-year-old woman

2:35

that give you segmental muscle atrophy.

2:39

And at the same time, edema, muscular edema.

2:44

So you think to yourself, is

2:45

this a primary muscle process?

2:47

Or is this a primary nerve process?

2:51

Now we all know from the history, she had surgery.

2:54

So the likelihood of it being a

2:55

primary muscle process isn't very high.

3:00

We also can see the distribution of edema.

3:03

See, it doesn't involve the

3:04

flexor digitorum brevis.

3:06

It doesn't involve the abductor digiti minimi.

3:10

But it does involve the flexor hallucis.

3:13

And it is centered in the region

3:17

of the tarsal tunnel space.

3:19

This is the tarsal tunnel space.

3:22

And what's in that space?

3:23

Well, we've got our friends Tom,

3:25

the posterior tibial tendon, bounded

3:27

superficially by the flexor retinaculum.

3:30

We've got our friend Dick, the flexor

3:33

digitorum, and Harry, the flexor hallucis.

3:37

And we also have...

3:39

Let's

3:39

keep looking.

3:45

We also have the neurovascular bundle.

3:49

We've got some veins right

3:50

here, some superficial veins.

3:54

We have a small artery right here, small artery.

3:58

But what's this?

4:00

It's that.

4:03

And what is that?

4:06

That's the last cut.

4:08

That's the last proximal cut.

4:09

So we have this thing.

4:12

Now we try and follow it down.

4:13

There it is.

4:15

Now it's gone.

4:16

And now we have that thing and that thing.

4:20

And now it looks more like a nerve breaking

4:22

up into the medial and lateral plantar nerves.

4:26

There they are right there, right there.

4:29

Now let's go back.

4:31

That is a stump neuroma.

4:34

That is the other end of the stump.

4:37

They transected her posterior tibial nerve.

4:42

Now, whether they spared the lateral

4:45

plantar nerve, is a question.

4:49

I'm not going to get into the anatomy and that

4:51

kind of detail, but I'm 100 percent confident

4:55

they transected her medial plantar nerve and most

4:58

likely transected the posterior tibial nerve.

5:02

We may have caught her in a period where

5:04

she just hasn't undergone the extent of

5:06

atrophy and the lateral musculature, but

5:09

this is what stump neuromas look like.

5:12

They look globular like the end of a thermometer.

5:15

They're slightly hyper intense on T2

5:18

weighted image, brighter than muscle,

5:20

but not usually as bright as fluid.

5:23

They enhance with contrast avidly.

5:26

We did not give any.

5:28

And because this has been ongoing for quite some

5:32

time, there was an attempt at repairing this.

5:35

It was unsuccessful.

5:37

Um, there, there really is no, no other treatment

5:41

other than physical therapy and pain management

5:43

with gabapentin and other nerve suppressing drugs.

5:47

So this is a nerve injury with stump neuromas

5:50

producing tarsal tunnel syndrome predominantly

5:55

in the distribution of the medial plantar nerve.

5:58

You do not need contrast for a case like

6:01

this, although I will admit that in many cases

6:03

of stump neuroma formation, where you have

6:06

tremendous amounts of scar, which you do here.

6:10

And you have anatomic distortion.

6:13

Maybe it's a trauma.

6:14

I've seen it happen with a sciatic

6:16

nerve in a motorcycle accident.

6:18

I've seen it happen with just about

6:20

every nerve in the body for somebody

6:22

that doesn't look at a lot of MRI.

6:24

If you do fat suppression contrast imaging,

6:27

it will light up the stump neuroma.

6:29

And it'll make it much easier for you to make the

6:31

diagnosis at the advanced or expert level.

6:36

It is mostly unnecessary to give

6:39

contrast for this diagnosis.

6:41

Now, if you are simply evaluating for

6:43

tarsal tunnel syndrome, you might consider

6:45

giving it to look for small schwannomas,

6:48

which can cause tarsal tunnel syndrome.

6:51

I don't need contrast to look at varices,

6:53

another cause of tarsal tunnel syndrome.

6:56

The most common cause, by the way, of

6:59

tarsal tunnel syndrome is repetitive.

7:01

friction from abuse or overuse

7:04

with a scarred flexor adnaculum.

7:06

This one is a post-operative iatrogenic example.