midface fracture patterns

Question 1

midface portion of facial skeleton spans from? includes which bones?

Answer 1

spans from cranial base to the maxillary occlusal plane
nasal bones
maxillary sinus walls
lefort 1
lefort II
Zygomatic arch
ZMC(zygomaticomaxillary)
wall, floor, rims of orbit, naso-orbital - ethmoid (NOE)

Question 2

most common midface fracture
dx by?

Answer 2

nasal bones - due to prominence and relative low energy required for fracture
characteristic signs of injury:
- pain
-bleeding
- swelling
- compromised nasal airway
- crepitation (crackling)
- palpable bony dislocation

Question 3

nasal bone fracture tx?
timeframe that is important to consider?

Answer 3

closed vs open reduction
closed should occur within 7-10/14 days of trauma so do not fuse into abnormal position

indications: fractures of nasal septal complex causing nasal airway obstruction
cosmetic reasons

Question 4

lefort I fracture diagnosis

Answer 4

it extends through the pyriform aperture of the nose anteriorly and the pterygoid plates (of sphenoid bone) posteriorly

it involves the lateral nasal wall (medial maxillary sinus wall) and the anterior and lateral max sinus wall

in a complete lefort I fracture, the maxilla is mobile

Question 5

lefort I fracture tx indications?

Answer 5

indications:
mobile maxillae with resulting malocclusion in cases where vertical restoration of one or more of the buttresses are indicated
usualy ORIF id the method of choice for mobile maxilla with malocclusion

no tx can result in anterior open bite due to traumatic impaction of maxilla posterior and inferior due to pterygoid pull

Question 6

lefort II fracture diagnosis

Answer 6

pyramidal fracture that involves separation of the central midface from the cranial base.

extends from the pterygoid plates and zygomatico-maxillary suture through the infraorbital rims and ends at the nasofrontal suture
maxilla also mobile as with lefort I, but less dramatic

Question 7

lefort II fracture tx

Answer 7

open reduction internal fixation
for a pure LeFort II fracture, rigid internal fixation is achieved at the zygomaticomaxillary buttresses and the infraorbital rims

very often additional points of fixation are needed based on the fracture pattern and comminution

Question 8

zygoma articulates with which bones
fracture usually?
best viewed how?
tx?

Answer 8

four
maxilla
sphenoid
temporal
frontal

best appreciated from a birds eye view and anatomic disclocation of zygoma best evaluated by digital exploration

most often zygoma is displaced at suture lines articulating with frontal, sphenoid, temporal, or maxillary

open reduction vs open reduction w/ internal fixation
some fractures may be stable after reduction, others will require fixation at the suture lines

Question 9

zygomatic arch fracture dx?
clinical findings?

Answer 9

palpable depression of zygomatic arch noted on exam and CT

pain on maximum opening likely

limited MIO is possible due to the origin of masseter muscle (originates on zygomatic arch and inserts onto the angle and lateral surface of mandibular ramus)

Question 10

indication for zygomatic arch fracture tx?

Answer 10

fracture segments impinge on the coronoid process of the mandible (resulting in limited opening)

correcting facial deformity (likely depression)

Question 11

maxillary vestibular approach / surgical approach to midface
accesses?
advantages?
disadvantage?
indicated for?

Answer 11

accesses the entire maxilla and much of the zygoma
advantages: no extraoral scarring, good access, simple closure
disadvantages: V2 (maxillary) parasthesia, healing complications if poor OH

indicated for : lefort fractures, ZMC fractures

Question 12

transconjunctival approach
accesses?
advantages?
disadvantage?
indicated for?

Answer 12

access: orbital rims (and orbital floor and walls)
advantages: no visible scars, access to inferior orbital rim
disadvantages: may need lateral canthotomy (lateral eye - cathus) to access lateral rim
indicated: to expose inferior orbital rim and lateral rim in isolated fractures or during ZMC recon)

Question 13

gillies and keen approaches to zygomatic arch

Answer 13

both are technically blind approaches - only true approach that grants full access is bicoronal flap

Gillies - 2.5 cm superior to helix of ear to avoid superficial temporal artery and dissection is superficial to temporalis muscle

keen incision is shortened vestibular incision, dissect superiorly in subperiosteal plane until can adequately reduce zygomatic arch