OMFS

Question 1

Name types of mandible fractures

Answer 1

1. Parasymphysis and symphysis (simple or complex)
2. Body (simple of complex)
   3.Angle (simple or complex)
3. Ramus
4. Condyle

Question 2

What is the treatment method of choice for paediatric patients (primary or mixed dentition) presenting with
-a simple or a complex symphysis or parasymphysis fracture?
-a simple little or moderately displaced body fracture

Answer 2

Splints and/ or closed treatment

-due to unerupted tooth buds

Question 3

What is the treatment method of choice for adult patients presenting with
-a simple symphysis or parasymphysis fracture?
-a simple body fracture
How is this completed?

Answer 3

Open reduction and internal fixation
(to avoid drawbacks and inconvenience of MMF - maxillomandibular fixation) for all

-superior and inferior border fixation required due to torsional forces in midline - 2 mini plates, 2 lag screws, a box plate, or single larger plate combined with arch bar

-ORIF recommended in all unstable #s and noncompliant patients

-Closed treatment is an option where plates and screws are not available for simple fractures

Question 4

What is a temporary external fixator in relation to mandible fractures?

Answer 4

Extraoral appliance
Provides temporary stabilisation of complex mandible fractures simultaenously affected several anatomic mandibular subunits

Question 5

What additional considerations compared to other simple fractures need taking into account with angle fractures?

Answer 5

Often involving 8 (requires extraction)
Usually displaced and require open treatment due to the action of the muscles of mastication

Question 6

1. Name the Muscles of mastication
2. Where do the muscles of mastication develop from - what does this mean about their innervation?
3. What are their actions?
4. What are their origins and insertions?

Answer 6

Develop from the first pharyngeal arch. Therefore innervated by branch of trigeminal nerve (CN V) - mandibular nerve (V3)

Masseter
-most powerful
-two parts: deep and superficial
-deep: origin - zygomatic arch of temporal bone; insertion - ramus of mandible
-superficial - maxillary process of zygomatic bone, insertion ramus of mandible
-action: elevation of mandible (closes mouth)

Temporalis
-Origin - temporal fossa of skull
-Insertion - coronoid process of mandible
-Action - elevation and retraction of mandible (closing mouth and moving jaw posteriorly)

Medial pterygoid
-Deep and superficial heads
-Deep: origin - maxillary tuberosity and pyramidal process of palatine bone
-Superficial: origin - medial aspect of lateral pterygoid plate of sphenoid bone
-Both heads attach to ramus near angle
-Actions: elevation of mandible (closing the mouth)

Lateral pterygoid
-Superior and inferior heads
-Superior: origin - greater wing of sphenoid
-Inferior: origin - lateral pterygoid plate of sphenoid
-Insertion: two heads converge into a tendon which attaches to neck of mandible
-Actions:
1. Bilateral - protraction of mandible and depression of chin
2. Unilateral action - ‘side to side’ movement of jaw

Question 7

Treatment of choice for ramus fractures

Answer 7

Nondisplaced ramus #s are relatively stable because of the unique anatomy of strong musculoaponeurotic system –> generally cons management i.e. soft diet/ MMF + guiding elastics if minimally or nondisplaced

Displaced –> ORIF may be considered

Question 8

Treatment of choice for condylar process fractures?

Answer 8

Controversial. Factors to consider:
1. Displacement –> more difficult to treat closed
2. Bilateral (guardsman) –> more difficult to treat closed
3. Non-compliant patients –> closed tx requires more frequent appointments and elastic wearing
4. Other #s –> maxillary #s may need intact mandible to position midface
5. Edentulism or poor dentition –> cannot use elastics or MMF
6. Age of patient –> younger = better outcome from closed treatment so open less indicated
7. VII nerve –> anatomically hazardous surgical area