0:01

Let's gild the lily, as we say,

0:03

and look at a few more cases of carotid encasement

0:07

to make sure that we understand the concepts.

0:09

On the top left, we have a case of nasopharyngeal

0:12

carcinoma. This tumor is outlined as you see here,

0:18

coming from the nasopharynx.

0:20

When we look at the internal carotid artery,

0:23

we see that there is less than 180 degrees of

0:27

involvement of the wall of the left internal carotid

0:32

artery. Therefore, were this to be operated on,

0:35

this tumor should be able to be peeled off

0:38

of the internal carotid artery.

0:39

Now,

0:40

nasopharyngeal carcinoma is not a surgical tumor.

0:44

Nasopharyngeal carcinoma is treated with

0:47

radiation therapy and chemotherapy.

0:49

And in this case, it's irrelevant because they're not

0:52

going to go in for the internal carotid artery.

0:54

Remember, however,

0:55

that radiation therapy can lead to vascular

1:00

inflammation and weakness in the wall of the

1:03

internal carotid artery and could lead

1:05

to potential carotid blowout.

1:08

How about this case in the bottom right,

1:10

this is an oropharyngeal cancer from

1:13

the palatine tonsil. However,

1:15

It has grown posteriorly and laterally to involve.

1:20

the carotid chief structures.

1:21

Here's our normal internal carotid artery.

1:24

Here's our normal internal jugular vein.

1:27

Here is our carotid artery.

1:29

Here, once again,

1:31

we see that the tumor comes to the wall of the

1:35

carotid artery but is involving less

1:38

than 270 degrees of involvement.

1:41

This tumor would be operated on, and it should be able

1:44

to be peeled off of the internal carotid artery

1:47

without causing it to have to be sacrificed.

1:50

This is the 270-degree rule that was established

1:54

in the article back in the 1980s.

1:58

Contrast that with this case.

2:00

So this is a very large tumor that has infiltrated

2:05

not just the deep lobe of the parotid gland,

2:08

but also the soft tissues laterally

2:10

in the right side of the neck.

2:12

If we look at the internal carotid artery in this

2:15

case, despite the very large size of the lesion,

2:19

the internal carotid artery wall is not involved

2:23

greater than 270 degrees. And therefore,

2:26

this very large tumor would be able to be peeled

2:30

off of the internal carotid artery.

2:33

How about this case? Here we have another case.

2:37

This was actually involving the soft palate

2:39

and growing into the posterior pharynx.

2:42

But in this case,

2:43

it seems as if the carotid artery is

2:46

circumferentially involved. You might argue, well,

2:49

how much is the normal width of the carotid wall?

2:54

The carotid wall should be indistinguishable.

2:56

Therefore, this small amount of tissue

3:00

that is around the posterior lateral wall of the

3:03

internal carotid artery can be presumed to be tumor.

3:06

And therefore,

3:07

this is 360 degrees of involvement of

3:10

the carotid artery. And therefore,

3:13

in this squamous cell carcinoma,

3:15

this carotid artery cannot be salvaged.

3:17

This is a primary tumor.

3:20

This is nodal disease. Here, once again,

3:23

we have the carotid artery with tissue which is

3:26

encircling the carotid artery. Not 360 degrees,

3:30

but very close to 360 degrees.

3:32

I put it from here all the way around.

3:35

You can see the nodal disease here,

3:37

nearly 360 degrees.

3:40

But greater than 270 degrees, this carotid

3:43

artery would not be able to be salvaged.

3:46

So again, treatment effect.

3:48

Either they say this is nonsurgical disease,

3:51

nonresectable disease, and treat

3:53

with chemo and radiation,

3:54

or they put up a balloon and occlude

3:58

the internal carotid artery,

4:00

see whether the patient is able to tolerate it

4:03

without neurological symptoms and take the carotid

4:06

artery at the time that they do the

4:08

nodal dissection. In this case,

4:10

the patient was treated with chemo radiation.