0:01

This is a patient who had a previous history of otitis media

0:06

and presented with conductive hearing loss.

0:09

At otoscopy, there really wasn't much that was visualized,

0:12

and the clinician was sort of confused as to why the patient

0:17

would have conductive hearing loss, given that there

0:19

didn't seem to be any active otomastoiditis.

0:23

So, CT scan was performed.

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And this is a little bit of a tricky CT scan.

0:28

So if we come up from below,

0:31

we have a little bit of maxillary sinus inflammation.

0:34

We come to the mastoid air cells and we see that there is

0:37

opacification of some of the mastoid air cells

0:40

on the left side compared to the right.

0:44

It's mild, but there is some opacification.

0:48

When we come to the middle ear cavity, however,

0:51

there really isn't any soft tissue around the middle ear

0:55

ossicles or in the epitympanic space, nor at the aditus ad antrum.

1:03

So a little bit of confusion.

1:05

And there is some evidence of chronic mastoiditis,

1:09

but not much with regard to the middle ear cavity.

1:13

However,

1:13

this is a patient who has a complication of otitis media.

1:19

And as we look at the middle ear ossicles,

1:22

we are struck by the fact that, although

1:25

we have an ice cream and ice cream cone,

1:29

head of malleus and short process of the incus,

1:33

when we look further inferiorly,

1:36

when we should be seeing two dots,

1:38

where we see on the right side,

1:39

the anterior dot being the neck of the malleus and

1:43

the posterior dot, the long process of the incus,

1:46

we see only the neck of the malleus.

1:50

We are not seeing the long process of the incus.

1:53

So, we know that this is the malleus because we can see

1:56

that there is a muscle coming across to attach to it.

1:59

That's the tensor tympani muscle,

2:01

remember, coming from the cochleariform process.

2:03

So here we see the stapes,

2:06

the anterior and posterior crus of the

2:09

stapes and it's coming together here.

2:12

We don't see a good capitulum and we are not seeing

2:16

that connection, the long process of the incus.

2:19

We have the short process of the incus,

2:21

but not the long process of the incus.

2:23

So given the history of the otitis media,

2:26

this is a case where there was bacterial infection which

2:30

caused osteolysis of the long process of the incus.

2:34

This is unusual, and by far,

2:38

when you see erosion of the middle ear ossicles,

2:41

we typically suspect a cholesteatoma,

2:44

rather than otitis media.

2:47

However, Joel Schwartz,

2:49

in his wonderful classic book "The Temporal Bone" describes

2:53

several different cases and has lots of examples of

2:57

pure otitis media causing erosion of ossicles.

3:01

And I think that's what happened in this case.

3:03

Differential diagnosis here is congenital absence

3:07

of the long process of the incus.

3:11

This can occur in second branchial arch anomalies, and we'll

3:14

talk about when we get to the congenital

3:15

portion of this mastery course.

3:18

One of the suggestions that one might make, that this is

3:23

congenital in etiology, is the lateral placement of the

3:29

middle ear ossicles in the epitympanic space.

3:32

So, here we have a very narrow Prussak's space compared to the

3:36

contralateral normal side, and that's what happens sometimes

3:40

when you have a congenital ossicular anomaly.

3:42

So, this differential diagnosis would

3:45

be of a congenital nature that...

3:49

it was a congenital loss of the long process of the incus.

3:52

In this case,

3:53

we do have evidence of chronic mastoiditis and we did have

3:56

a previous history of otitis media, and the acute onset of

4:01

conductive hearing loss, thought to be due to the

4:03

osteolysis of the long process of the incus.