Trauma (mandible)

Question 1

during initial exam, what distribution do we need to note?

Answer 1

Any altered IAN sensation distribution

The IAN can be damaged during ORIF

Question 2

In pediatric mandibles, what causes areas of weakness?

Answer 2

unerupted teeth

developing 3rds particularly

Question 3

On initial exam of a mandible fracture, what 3 things are important to evaluate?

Answer 3

Derangement of occlusion
(ask if it differs from before injury)
Altered sensation of IAN
Step offs in occlusion

Question 4

What are the 3 treatment goals when treating a mandible fracture?

Answer 4

1. Restoration of pre-injury occlusion
2. Early return to function
3. Acceptable cosmesis

Question 5

Describe load bearing vs load sharing

Answer 5

load bearing: when a fracture does not allow any stabilizing forces across the fracture line. such as comminuted fractures, complex fractures, or pathologic fractures (spanning a defect)

Load sharing: when buttressing can occur between the two fracture segments which help to naturally stabilize the fracture and resists movement across the fracture

Question 6

what types of fractures normally require load bearing osteosynthesis? (4)

Answer 6

Comminuted fractures
Infected fractures
Pathologic fractures
fx’s in atrophic/edentulous mandbiles

Question 7

Load bearing plates are typically?

What type of screws are normally used? 2

How many screws should be placed on each side of the fracture?

Answer 7

large and thick to provide enough strength for stabilization

bi-cortical (which ensures maximum fixation) and locking (to prevent displacement of bone when tightening screw)

3 screws on each side of fx

Question 8

If nasal intubation isn’t possible in the OR, what 2 other methods can be used for sedation?

Answer 8

Submental intubation or tracheostomy

an armored oral tube can also be used in rare cases that have enough room behind the last molar to pass the tube behind it and fixate it to that molar

Question 9

How is a parasymphysis fx treated?

what if there is a b/l fx?

Answer 9

Closed reduction with 4-6 weeks MMF

you could used monocortical plates/screws if pt won’t be compliant

if a b/l mandible fx is present, most likely need ORIF

Question 10

due to the pull of musculature, what can happen to a parasymphseal fracture that is not treated? (esthetically)

Answer 10

mandibular widening

Question 11

What is the most common approach for a noncomminuted parasymphysis fx?

Answer 11

transoral

although, you still need to visualize the inferior border

b/c you go through the mentalis muscles, you must resuspend the mentalis during closing

Question 12

if a parasymphasis fracture (or any mandibular fx for that matter) cannot be reduced adequately, what is most likely the cause?

Answer 12

a DA fracture causing a tooth in the fracture line to prevent appropriate reduction

Question 13

How are most mandibular body fx’s treated? open vs closed

Answer 13

Closed (if isolated)

can be treated open if necessary (I’m guessing if another fx is present)

Question 14

for ORIF of mandibular fx’s, what depth of the drill should be used?

Answer 14

6-8mm with a stop

Question 15

How are angle fx’s treated? Open vs Closed

Answer 15

most are open unless non-displaced and has a favorable fx

Question 16

Do you want to removed the wisdom tooth when plating an angle fx?

when would you? 4

Answer 16

No, it will weaken the fx line and create a defect basically

You would want to remove a wisdom tooth when it is

1. prevents fx reduction
2. infected
3. fractured
4. if no other bone needs to be removed in order to extract

Question 17

how often to plates used to tx the angle fail? %

Answer 17

20%

Question 18

When multiple mandibular fx’s are present, and you plan of fixating one of the fx’s, which one do you fixate and why?

Answer 18

generally, you fixate the more anterior fx to avoid the “wish boning” or widening of the mandible from the muscular pull. Occlusion can seem adequate when in reality, the wish boning is present