0:01

The nomenclature of fractures of the temporal bone

0:04

has undergone changes over the course of time.

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Initially,

0:09

the fractures were labeled as longitudinal for those

0:12

that were coursing along the plane of the temporal

0:15

bone versus transverse fractures

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which were more vertically oriented fractures.

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Both of these can cause facial nerve injury.

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Turns out that the longitudinal ones were the ones

0:28

that had a higher rate of facial nerve injury.

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However, over the course of time,

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it was noted that many fractures are oblique in their

0:37

orientation, and therefore, cannot be accurately

0:41

characterized as being longitudinal or transverse.

0:45

When you have fractures that course

0:47

into the middle ear cavity,

0:49

you have a high rate of ossicular anomalies.

0:52

The transverse fractures were the ones that seemed to

0:56

have a higher rate of sensorineural hearing loss,

0:58

and subsequently, those fractures were recharacterized.

1:03

We now have a new terminology.

1:05

The fractures are characterized, as quote,

1:08

otic capsule sparing or otic capsule violating.

1:13

The reason for this is that those vertical

1:16

fractures that cross into the labyrinth,

1:21

the cochlea or the vestibule

1:23

were the ones that had the sensorineural hearing loss,

1:26

and therefore, they were better characterized

1:29

as otic capsule violating fractures.

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Now,

1:33

you can have a vertical fracture which

1:35

is lateral to the otic capsule,

1:37

and that would not cause a sensorineural hearing

1:40

loss. And that's why the nomenclature has changed.

1:44

So most of the otic capsule sparing fractures

1:48

occur from a temporoparietal blow.

1:50

They cause conductive hearing loss because

1:53

they may injure the ossicles.

1:55

So this is analogous to the longitudinal or

2:00

horizontal fractures or oblique fractures.

2:03

The otic capsule violating fractures are usually

2:05

from an occipital-oriented blow.

2:08

They are associated with sensorineural hearing loss

2:10

because they're cutting across either

2:12

the cochlea or the vestibule,

2:13

where you can truly affect the sensori-

2:16

neural organ of hearing.

2:17

They may also cause facial nerve paralysis more

2:20

commonly than the otic capsule sparing ones,

2:23

and they may show CSF

2:25

fistula.

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Complications of fractures include

2:28

conductive hearing loss.

2:29

Blood in the middle ear cavity will

2:31

lead to a conductive hearing loss.

2:34

And that's why imaging is so important.

2:36

The clinicians can't see past the blood at the

2:40

tympanic membrane, and so they're unable to tell

2:43

whether or not there is an ossicular fracture that is

2:46

causing the conductive hearing loss or whether it's

2:48

due to the blood in the middle ear cavity,

2:51

the hemotympanum.

2:52

And so it's very important to pay attention

2:55

to those middle ear ossicles.

2:57

Other fracture complications include CSF leakage

3:01

which can occur from involvement

3:02

of the tegmen tympani,

3:03

which may be more common in vertical fractures or

3:07

otic capsule involving or violating fractures.

3:11

Hemorrhage in the inner ear structures

3:14

can lead to labyrinthitis ossificans,

3:18

and that, in and of itself, can lead to a sensorineural

3:21

hearing loss. And finally,

3:22

with any of these fractures,

3:24

it may extend along and into the carotid artery and

3:27

lead to either dissection of the carotid

3:29

artery or a pseudoaneurysm.

3:31

Here is an example of a temporal bone showing a

3:35

vertical fracture which is entering into the cochlea.

3:40

Here is the plane of the fracture entering into the

3:43

cochlea and causing an otic capsule violating

3:48

fracture leading to sensorineural hearing loss.

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This patient also, as you can see,

3:54

has a portion of the long process of the incus

3:57

which never connected to the stapes.

3:59

And the patient did have disarticulation of the

4:03

lenticular process of the incus with the stapes, leading to conductive hearing loss,

4:06

as well as sensorineural hearing loss. Another example of a fracture.

4:11

In this case,

4:15

you see the fracture line coursing along

4:16

the horizontal or longitudinal plane,

4:19

and this one is sparing the otic capsule.

4:23

You don't see any fracture involving the cochlea vestibule,

4:27

semicircular canals at all.

4:29

However, when we look at the plane of the fracture,

4:32

we see that there is separation between

4:34

the head of the malleus and the incus.

4:37

.

4:41

The ice cream cone has fallen.

4:44

I'm sorry.

4:44

The ice cream has fallen off of the ice cream cone.

4:48

It's disarticulated medially,

4:51

so there's incudomalleolar dislocation.

4:55

There's a portion of the ice cream cone that has

4:59

broken off right here. It hasn't been bitten off.

5:01

That's a fracture of the short process of the incus.

5:05

And then we have the opacification of blood in the

5:09

middle ear cavity leading to a conductive

5:11

hearing loss. If you notice,

5:13

we have a portion of the stapes here without

5:17

connection to the long process of the incus.

5:20

So this patient had a otic capsule sparing temporal

5:26

bone fracture associated with incudomalleolar and

5:30

incudostapedial dislocation,

5:33

as well as a fracture of the incus and a hemotympanum.