Mandible Fractures and Surgical Approaches Flashcards

1
Q

most common causes of mandibular fractures

A

motor vehicle accidents
interpersonal violence
falls
sports injuries

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2
Q

incidence by percentage on location of fracture on mandible

A

isolated fractures : 70%
unilateral: 53%

angle: 30%
condyle: 23%
symphyses:22%
body: 18%
Ramus: 2%
Coronoid process: 1%

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3
Q

favorable fractures vs unfavorable

A

favorable:
proximal segment directed in line with distal segment

no vertical or medial displacement of the fracture

common in fractures more anteriorly located in the mandibe

unfavorable:
proximal segment displaced upward and medially

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4
Q

what to include in clinical exam of possible mandibular fracture

A

changes to occlusion
neurologic exam
movement restrictions
facial asymmetry
lacerations, hematomas, ecchymosis

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5
Q

5 main/ general principles of treatment

A

re-establish occlusion
antibiotic coverage for open fractures and intact teeth in the line of fracture
attempt to maintain all canines and lone teeth in an arch
extract all non-restorable / hopeless teeth
monitor nutrition

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6
Q

indications for closed reduction ?
general definition

A

not breaking mucous membrane – physically moving bones back to place without surgically exposing the bone
does not dis-clued use of fixation

  • nondisplaced, favorable fractures
  • grossly communited with intact periosteum
  • significant loss of overlying soft tissue
  • edentulous MANDIBLE
  • developing dentition (younger pts / children)
  • coronoid process fractures
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7
Q

indications for open reduction

A
  • displaced, unfavorable fractures (proximal segment is up and medial)
  • edentulous mandible with severe displacement
  • multiple facial bone fraactures
  • bilateral, displaced condylar fractures
  • edentulous MAXILLA
  • soft tissue between displaced fracture segments
  • when closed reduction is inappropriate
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8
Q

bridle wiring indications?
proper placement includes?

A

temporary stabilization
prevent more tissue damage
protects airway
prevents pain from segment mobility and muscle cramping

  1. anesthetize
  2. reduce segments manually
  3. pass wire around neck of teeth on either side of fracture
  4. tighten wire in a clockwise fashion to continue reducing fracture
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9
Q

‘basic’ 6 steps for arch bars

A
  1. anesthetize
  2. measure bar: must be 2 teeth proximal to fractures site
  3. secure bar by placing wire around second premolars
  4. place circum-dental wires (24 gauge) for fracture reduction, starting from midline
  5. for fixation, place box wires (26 gauge)
  6. ensure proper occlusion before completely tightening wires
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10
Q

signs of condylar fractures

A

-ipsilateral occlusal prematurity and contralateral open bite
-deviation of mandible towards fractured side opening
- anterior open bite noted with bilateral fractures
- more subtle signs: limited opening, limitations of movements, preauricular pain

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11
Q

ORIF

A

open reduction / internal fixation

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12
Q

class 1 condylar fracture in terms of
ramus shortening in mm
degree of displacement
treatment

A

Class 1
ramus shortening - less than 2mm
degree of displacement - less than 10
treatment- closed

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13
Q

class II condylar fracture in terms of
ramus shortening in mm
degree of displacement
treatment

A

class II condylar fracture:
ramus shortening - 2-15mm
degree of displacement - 10-45 degrees
treatment- ORIF (open reduction internal fixation)

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14
Q

class III condylar fracture in terms of
ramus shortening in mm
degree of displacement
treatment

A

class III condylar fracture in terms of
ramus shortening - more than 15 mm
degree of displacement - more than 45 degrees
treatment - ORIF

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15
Q

absolute indicators for open reduction in condylar fractures

A

lateral extracapsular displacement of condyle
malocclusion not amenable to closed reduction (functional reduction of ramus height)

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16
Q

strong evidence for open reduction in condylar fracture

A

bilateral condylar fractures

17
Q

when to treat condylar fractures with closed reduction

A

nondisplaced or incomplete fractures
isolated intracapsular fractures

18
Q

surgical goals of condylar fractures

A

pain free mouth opening with interincisal distance beyond 40 mm
good excursive movements
restoration of occlusion
stable TMJs
facial and jaw symmetry

success:
distraction of ramus
proximal condyle controlled and manipulated
anatomic reduction with more than one screw on proximal segemnt

19
Q

management of fractures in children

A

younger than 15 : early mobilization and soft diet
- guiding elastics can help with establishing occlusion

ORIF indications are same as absolute indications for adults

20
Q

submandibular (Risdon) incision approach
incision is where?
6 steps
avoid?

A

incision: 4-5 cm long, placed 2cm below angle of mandible in skin crease (ideally)
1. incision
2. dissect subcutaneous fat and superficial fascia to platysma
3. undermine skin incision to facilitate closure
4. sharply dissect platysma to identify superficial layer of deep cervical fascia
5. Dissect deep cervical fascia to inferior border of mandible using nerve stimulator as a guide (keep dissection 1.5 cm below inferior border)
6. Incise pterygomasseteric sling and periosteum at inferior border and reflect superiorly

avoid disruptions to submandibular (and parotid) capsules
either retract or ligate facial vessels (node of stahr)
if treating condylar fracture, ramus is shortened so incision should be 1.5-2 cm below anticipated site of reduced mandible (will require MMF placement)

21
Q

MM nerve is ___ to the vein? branches from?
maneuver / procedure that preserves nerve?

A

Marginal mandibular from facial nerve
MM nerve is superficial to the vein

Hayes- Martin Maneuver
- similar to Ridson of submandibular approach to condylar fracture but ligate the posterior facial vein (MM nerve is superficial to the vein)

22
Q

retoromandibular approach incision and following three outlined steps
good for ___ fractures?

A

good for ramus and subcondylar fractures that can be plated
1. incision
- 0.5cm below earlobe and extends inferior to 3-3.5 cm, just behind posterior border of mandible
2. identify platysma, deep cervical fascia, and parotid capsule and incise sharply
3. bluntly dissect through parotid parallel to facial nerve until coming in to contact with periosteum of posterior border of mandible
- nerve dissection: 1 cm proximally ad 1.5-2 cm distally
4. sharply incise pterygomaxillary sling and periosteum at angle of mandible and reflect superiorly
- caution of retromandibular vein.

23
Q

rhytidectomy approach field of view

A

variation of retromandibular with better scar concealment

provides same exposure as the retromandibular and preauricular access combined - but skin incision is placed in a more cosmetically acceptable location

24
Q

rhytidectomy incision location
elevate?

A

1.5 - 2 cm superior to zygomatic arch just posterior to anterior extent of hairline
- curves posterior and inferior into a pre-auricular incision
- continues under earlobe and extends 3 cm onto posterior surface of auricle

  1. incision
  2. elevate skin flap with wide undermining angle of mandible and anterior to posterior border of mandible
    - caution to great auricular nerve deep to subcutaneous plane
  3. retract skin anteriorly and follow retromandibular approach*
25
Q

indications for pre-auricular approach?
incision location?

A

TMJ and temporal access (w/ extenstion)
incision is 2.5-3.5 cm along pre-auricular folds
- extends from superior ear to inferior attachment of ear

26
Q

five basic steps to pre-auricular approach

A
  1. incision - 2.5-3.5 cm along preauricular folds
  2. identify superficial temporal fascia and undermine incision in this plane along zygoma
    - dissection should be parallel to external auditory cartilage
  3. identify lateral layer of superficial temporal fascia and incise to 2-3 cm anterior to skin incision
  4. proceed anterior and inferior about 1 cm to identify lateral eminence
  5. open capsule at fracture location
27
Q

intraoral : body, angle, ramus incision

A

incise mucosa to bone perpendicular to bone
- leave 3-5 mm of tissue below MGJ
- avoid mental nerve anteriorly

extend incision proximally along external oblique ridge up to occlusal plane in subperiosteal fashion

ramus exposure: strip masseter, buccinator, and temporal tendon
subcondylar exposure: strip masseter

28
Q

goals of fixation

A

anatomic reduction
fracture fragment compression
immobilization

29
Q

functionally stable fixation means?
bone heals by?

A

enough stability between fragments to permit masticatory function but NOT bony union

bone heals by secondary / indirect healing
- periosteal callus forms: nature’s internal fixation
- fractured fragment ends resorb
- tissue differentiation occurs to go from FIBROUS TO OSSEOUS

30
Q

LOAD BEARING FIXATION
- indications?
-example

A

plate is sufficient strength and rigidity to bear entire load of masticatory function

indications:
communited fractures
severe atrophy
defect fractures

example: recon plate

31
Q

LOAD SHARING FIXATION
indications
examples

A

plate is insufficient stability to bear entire load of masticatory function

indications: simple linear fractures
- requires solid bony fragments on each side of fracture

examples
- miniplate systems
- lag screws