Mandible Fractures and Surgical Approaches Flashcards
most common causes of mandibular fractures
motor vehicle accidents
interpersonal violence
falls
sports injuries
incidence by percentage on location of fracture on mandible
isolated fractures : 70%
unilateral: 53%
angle: 30%
condyle: 23%
symphyses:22%
body: 18%
Ramus: 2%
Coronoid process: 1%
favorable fractures vs unfavorable
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
what to include in clinical exam of possible mandibular fracture
changes to occlusion
neurologic exam
movement restrictions
facial asymmetry
lacerations, hematomas, ecchymosis
5 main/ general principles of treatment
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
indications for closed reduction ?
general definition
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
indications for open reduction
- 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
bridle wiring indications?
proper placement includes?
temporary stabilization
prevent more tissue damage
protects airway
prevents pain from segment mobility and muscle cramping
- anesthetize
- reduce segments manually
- pass wire around neck of teeth on either side of fracture
- tighten wire in a clockwise fashion to continue reducing fracture
‘basic’ 6 steps for arch bars
- anesthetize
- measure bar: must be 2 teeth proximal to fractures site
- secure bar by placing wire around second premolars
- place circum-dental wires (24 gauge) for fracture reduction, starting from midline
- for fixation, place box wires (26 gauge)
- ensure proper occlusion before completely tightening wires
signs of condylar fractures
-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
ORIF
open reduction / internal fixation
class 1 condylar fracture in terms of
ramus shortening in mm
degree of displacement
treatment
Class 1
ramus shortening - less than 2mm
degree of displacement - less than 10
treatment- closed
class II condylar fracture in terms of
ramus shortening in mm
degree of displacement
treatment
class II condylar fracture:
ramus shortening - 2-15mm
degree of displacement - 10-45 degrees
treatment- ORIF (open reduction internal fixation)
class III condylar fracture in terms of
ramus shortening in mm
degree of displacement
treatment
class III condylar fracture in terms of
ramus shortening - more than 15 mm
degree of displacement - more than 45 degrees
treatment - ORIF
absolute indicators for open reduction in condylar fractures
lateral extracapsular displacement of condyle
malocclusion not amenable to closed reduction (functional reduction of ramus height)
strong evidence for open reduction in condylar fracture
bilateral condylar fractures
when to treat condylar fractures with closed reduction
nondisplaced or incomplete fractures
isolated intracapsular fractures
surgical goals of condylar fractures
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
management of fractures in children
younger than 15 : early mobilization and soft diet
- guiding elastics can help with establishing occlusion
ORIF indications are same as absolute indications for adults
submandibular (Risdon) incision approach
incision is where?
6 steps
avoid?
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)
MM nerve is ___ to the vein? branches from?
maneuver / procedure that preserves nerve?
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)
retoromandibular approach incision and following three outlined steps
good for ___ fractures?
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.
rhytidectomy approach field of view
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
rhytidectomy incision location
elevate?
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
- incision
- 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 - retract skin anteriorly and follow retromandibular approach*
indications for pre-auricular approach?
incision location?
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
five basic steps to pre-auricular approach
- incision - 2.5-3.5 cm along preauricular folds
- identify superficial temporal fascia and undermine incision in this plane along zygoma
- dissection should be parallel to external auditory cartilage - identify lateral layer of superficial temporal fascia and incise to 2-3 cm anterior to skin incision
- proceed anterior and inferior about 1 cm to identify lateral eminence
- open capsule at fracture location
intraoral : body, angle, ramus incision
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
goals of fixation
anatomic reduction
fracture fragment compression
immobilization
functionally stable fixation means?
bone heals by?
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
LOAD BEARING FIXATION
- indications?
-example
plate is sufficient strength and rigidity to bear entire load of masticatory function
indications:
communited fractures
severe atrophy
defect fractures
example: recon plate
LOAD SHARING FIXATION
indications
examples
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
