0:01

Well, let's do our wrap-up of the carotid space imaging.

0:05

We used our mnemonic vitamin C and D to identify the

0:09

different categories of pathology that affect the carotid

0:12

space. We initially started with the vascular lesions,

0:15

which included our primary vasculopathies,

0:17

including Takayasu's arteritis and fibromuscular dysplasia,

0:21

but we also included some of the congenital

0:24

lesions that lead to vasculopathies,

0:27

including Marfan syndrome and Loeys-Dietz syndrome.

0:32

Next,

0:32

we looked at the infections that

0:34

can affect the carotid space.

0:35

These are usually coming from odontogenic sources or

0:39

pharyngitis with secondary involvement of the

0:42

carotid artery and/or the jugular vein.

0:45

When that jugular vein causes thromboembolism

0:48

with septic emboli.

0:50

We called that Lemierre's disease or postanginal sepsis.

0:55

When we had the inflammation at the floor of the mouth and

0:59

extending into the submandibular space and from there

1:01

into the carotid space. We called it Ludwig's angina,

1:05

recognizing that that may lead to a secondary arteritis

1:09

and it also may lead to compromise of the airway.

1:12

Next,

1:13

we talked about traumatic injuries to the vessels that

1:17

included dissection on the arterial side of the carotid

1:21

artery in the carotid sheath with secondary

1:26

involvement of the artery's wall,

1:30

leading to a pseudoaneurysm.

1:32

And we went through the Biffl's classification of the

1:35

different types and severity of the traumatic

1:38

injury to the blood vessels.

1:41

We skipped

1:42

acquired metabolic and went to idiopathic diseases of

1:45

which carotidynia, that inflammatory condition that causes

1:49

neck pain and is associated with thickening of the wall,

1:53

possible narrowing of the vessel with this inflammatory

1:57

tissue around the wall of the carotid artery,

2:01

which is exquisitely sensitive to nonsteroidal

2:05

anti-inflammatory drugs for its resolution.

2:08

This is a disease entity that usually resolves within two

2:11

weeks after nonsteroidal anti-inflammatory drugs.

2:16

We then cruise to the neoplasms of

2:19

the vitamin C and D mnemonic,

2:21

and I emphasize that most of these are going

2:24

to be benign lesions, which makes me happy,

2:27

and they are dominated by paragangliomas.

2:30

Paragangliomas include glomus jugulare,

2:34

glomus vagale, and carotid body tumors, with a fourth

2:40

paraganglioma affecting the temporal bone,

2:42

that being the glomus tympanicum.

2:44

I mentioned that sometimes glomus jugulare will grow into

2:47

the tympanic cavity and then we would use

2:50

the term glomus jugulotympanicum.

2:53

We mentioned about schwannomas and we said that the most

2:57

common of the schwannomas of the carotid sheath

2:59

are from the vagus nerve.

3:01

Now, they may occur from the 9th cranial nerve,

3:03

the 11th cranial nerve, and the 12th cranial nerve high up

3:07

before those nerves peel off to innervate the tongue and

3:11

the pharynx, or in the case of the 11th cranial nerve,

3:14

the sternocleidomastoid muscle and trapezius sympathetic

3:18

nervous system. Plexus schwannomas do occur.

3:21

They generally displace the carotid and jugular vein

3:25

anteriorly. Meningiomas can occur in the carotid sheath.

3:29

However, they usually come from the skull base.

3:31

So you'll see them at the jugular foramen, for example,

3:35

or elsewhere in the skull base, growing

3:37

secondarily into the carotid sheath.

3:41

When we think about malignancies of the neoplasm,

3:43

we have our 270-degree rule, and that is that if the tumor

3:48

has less than 270 degrees of circumferential

3:52

involvement of the carotid artery,

3:55

it likely can be peeled off surgically from the carotid

3:58

artery without sacrificing the carotid artery.

4:01

However, once it gets over 270 degrees,

4:04

whether it's the primary tumor coming from the mucosal

4:07

space or the nodal tumor coming from lymph node metastases,

4:12

that carotid artery will have to be sacrificed.

4:16

I didn't mention vasculitis associated with drugs.

4:19

In our experience, that vasculitis is most commonly

4:22

associated with cocaine use, and it can show the same

4:26

inflammatory pattern as one would see, for example,

4:30

in carotiditis.

4:32

So take-home messages.

4:34

Remember that there are vascular lesions which may be

4:37

caused by the intrinsic vascularopathy, trauma, or

4:42

infectious etiologies. Outside of the blood vessels,

4:46

you may see benign masses, and those are

4:48

our paragangliomas and schwannomas.

4:51

The carotid space is most often invaded by malignancy

4:55

by pharyngeal squamous cell carcinoma.

4:58

And we have a 270-degree rule of encasement.

5:02

If the cancer involves more than 270 degrees of the

5:05

circumference of the carotid artery,

5:07

that carotid artery will not be able to

5:09

be salvaged and must be sacrificed.

5:12

And that is a good surgical caveat that

5:15

should be expressed in your reports.

5:18

And with that, I will say have a good day, and

5:21

I hope you enjoyed carotid space imaging.