0:01

This is a patient who had both conductive hearing

0:03

loss as well as vertigo. On the axial scans,

0:09

we know now, in these young adults, to look for a specific

0:15

area for fenestral otospongiosis.

0:19

What we do is we look for the stapes,

0:22

which is seen here.

0:26

We have the vestibule,

0:28

and we are at the level of the oval window.

0:31

And if we look at the anterior footplate of the stapes,

0:35

we're going to look for any evidence of

0:37

demineralized bone. And with that introduction,

0:41

hopefully, you identify that this

0:43

is the area of otospongiosis.

0:49

So, again, this area of bone is lower in density than the

0:55

remainder of the bone around the cochlea

0:57

and vestibule. And if I scroll,

1:00

around this,

1:02

you can see that this plaque of demineralization

1:04

is present on about three or four slices.

1:08

But by the end of this course,

1:09

you'll be making this diagnosis pretty easily.

1:12

Now, how do we explain the vertigo?

1:14

Well, the vertigo may be a toxic effect in the

1:19

semicircular canals by the spongiotic bone

1:22

enzymatic entry into the vestibule, and from there,

1:26

going into the semicircular canals.

1:28

But in this patient,

1:30

what we found was that there was, in addition to

1:34

otospongiosis, the dehiscence of the superior

1:38

semicircular canal, no bone over top of the

1:40

superior semicircular canal on the left side.

1:45

On the spiral reconstruction,

1:48

if we follow the superior semicircular canal as

1:52

the sections are cut across the top of the

1:55

superior semicircular canal, you see some

1:57

areas where you have lost the bone,

2:00

overlying that semicircular canal

2:04

in an area of dehiscence.

2:06

So this patient had not just fenestral

2:10

otospongiosis and conductive

2:12

hearing loss on that basis,

2:14

but had Tullio's phenomenon and vertigo associated

2:18

with loud noises, secondary to superimposed

2:21

dehiscence of the superior semicircular canal.