0:01

As I mentioned in the Yousem literature and experience, nasal bone fractures

0:06

are the most common of the facial bone fractures followed by orbital fractures.

0:12

In the maxillofacial literature, they say that mandibular fractures are

0:17

more common than orbital wall fractures. When the mandible fractures, there's

0:21

different portions of the mandible that will fracture and they include:

0:25

The condyle, most commonly; the mandibular body, 21%; the symphysis, which

0:32

is the frontal portion, in 14%; and then you have the less common

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sites, the angle, the ramus, the alveolar ridge and the coronoid process.

0:41

Now, remember that the mandible is a ring

0:44

and, therefore, if you have a fracture on one side of the mandible,

0:48

it is highly likely that there is a fracture on the other side

0:52

of the mandible, but not necessarily the same portion. So it's not unusual

0:57

for us to see a symphysis fracture in association with a contralateral condyle

1:02

fracture, or a body fracture and a ramus fracture. So it's not a

1:06

symmetric fracture that tends to occur. The importance of mandibular fractures

1:11

is that there are a lot of different complications that could occur including:

1:15

Loss of the teeth because of a fracture that crosses the neurovascular bundle;

1:20

mal union or non union of the fracture; avascular necrosis, and this tends

1:26

to occur with neck fractures with avascular necrosis of the distal portion,

1:30

that being the mandibular condyle; mirror displacement or deformity and

1:35

malocclusion are fairly common, if it's not reduced appropriately;

1:40

secondary temporomandibular joint ankylosis or degenerative change; and

1:46

of course, whenever you have a fracture that may communicate with the oral

1:51

cavity, you can have infection. I just want to point out the parts

1:57

of the mandible. The symphysis being that frontal portion,

2:01

the body just off the midline, and then we have the angle of

2:06

the mandible where it starts to turn upward,

2:09

the ramus, the coronoid process, and then the condylar fracture which leads

2:15

to the mandibular condyle being separated here. Those that are occurring

2:20

at the neck or sub condylar portion are the ones that have the

2:23

highest risk of avascular necrosis. And here you see a few examples on

2:28

slides of fractures that involve the symphysis and body on the right side,

2:33

and a relatively subtle fracture which is occurring at the angle and ascending

2:39

ramus of the left side of the mandible. Here's a different fracture

2:44

coming across the symphysis. Here's an angle of the mandible fracture on

2:49

coronal images. So this is all part of that ring where we may

2:53

have fractures on both sides of the mandible but not necessarily symmetric

2:58

ones. By mandibular ring, I'm not talking about cosmetic rings that some

3:03

people will use to puncture their mandible or their tongue or their floor

3:09

of the mouth. Here's another example of a fracture, this is in a

3:13

child, where the fracture, as you can see, is involving the ascending ramus

3:17

of the mandible with displacement of the fracture fragments. Always be careful

3:22

with the mandibular fractures that there's no compromise of the oral airway

3:28

because loss of an airway in a child or an adult with an

3:33

associated fracture can lead to, obviously, hypoxic ischemic injury. As

3:38

you can see with this case, you may also lose some of the

3:41

teeth. In this case, this is the un erupted mandibular molar tooth on

3:47

the right side. Here, we've lost that tooth. It's not extracted;

3:51

it's been lost in the patient's mouth. And sometimes you may even find

3:55

the tooth as something that the patient may aspirate into the airway.

4:00

Fractures that involve the mandibular nerve canal, which is this structure

4:04

right here that you follow down into the mandibular alveolus, may also lead

4:10

to decrease or numbness in the soft tissues anterior to the mandible.

4:18

Here, you can see a fracture which is going across the root of

4:22

the tooth. Here is the same fracture on the sagittal reconstruction with

4:28

comminution and, again, the tooth has been lost, either spit out or into

4:33

the patient's airway or swallowed. Three dimensional reconstructions are

4:39

really useful in the display of the mandibular fractures, particularly as

4:44

the surgeons contemplate the reduction of the fracture into a normal alignment.

4:49

So we like doing these 3 D recons to better display those displacements

4:54

when the fracture is either comminuted or medial or laterally displaced.