mandibular fractures Flashcards
first priorty in any trauma
basic life support
have knowledge of
muscles of mastication
origin, insertion
aids understanding displacement of #
MoM that help close the mandible
medial pterygoid
temporalis
masseter
muscles that push the mandible in the down
suprahyoid
mylohyoid
anterior belly digastric
how does displacement of mandibular # occur
medial pterygoid, temporalis, masseter will pull the fracture up
whilst the mylohyoid and anterior belly digastric will pull down
DISPLACEMENT
what dictates the pace of management of pt
displacement of fracture
other important structures in teh mandible
inferior dental nerve - branch of mandibular division of trigeminal (sensation to lower lip, gingivae etc)
possible causes if pt complains of numbess of lower lip
trauma
infection
cancer
etc
need to investigate
8 clinical signs/symptoms of mandibular fractures
- Pain, swelling, limitation of function (unable to open, limitation of side-side movement)
- Occlusion derangement (not able to bite normally – bite prematurely, moved from correct position, step deformed)
- Numbness of the lower lip
- Loose or mobile teeth
- Bleeding (limited to area of #)
- Anterior open bite – when ramus is shortened, post teeth meet prematurely (bilateral subcondylar fracture)
- Facial asymmetry
- Deviation of the mandible to the opposite side
possible sites of bleeding which indicate mandibular #
FOM - under mucosa=sublingual haematoma
ear
around teeth
classification of mandibular fractures
7 categories
involvement of surrounding tissue
number of fractures
side of fractures
site of the fractures
direction of fracture line
specific fractures
displacement of the fractures
used to describe fracture, if more than one – description for each
options for involvement of the surrounding tissue for mandibular fractures
3
- Simple - # within bone, surrounding soft tissue is in tact
- Compound - # exposed to outside, soft tissue no longer in tact
- Comminuted – multiple segments
simple fracture
within bone, surrounding soft tissue is in tact
compound #
exposed to outside, soft tissue no longer in tact
comminuted #
multiple segments
number of # options
3
single
double
multiple
side of fracture options
2
unilateral
bilateral
site of mandibular fracture options
8
- Angle
- Subcondylar
- Parasymphsyeal (centre)
- Body
- Ramus
- Coronoid
- Condylar fracture (intra-extra capsular)
- Alveolar process
direction of fracture line options
2
- Favourable – direction of # line limits the displacement
- Unfavourable – direction of # line encourages displacement
specific features of mandibular fractures
2 options
- Green stick fractures – still attached, soft bone (children), doesn’t completely break
- Pathological fractures – osteoporosis, osteomyelitis, paget’s disease, expanding cystic lesion
green stick fractures
still attached,
soft bone (children)
doesn’ completely break
pathological fractures
osteoporosis,
osteomyelitis,
paget’s disease,
expanding cystic lesion
displaced fractures
need surgical intervention
undisplaced fractures
may not require surgical intervention
6 factors that can cause displacement of mandibular fractures
- Direction of the fracture line – unfavourable then likely to be displaced (not always – opposing occlusion can prevent displacement)
- Opposing occlusion
- Magnitude of force
- Mechanism of injury – single/multiple/size
- Intact soft tissue – intact ->unlikely
- Other associated fractures – more=higher displacement chance
6 factors that can cause displacement of mandibular fractures
- Direction of the fracture line – unfavourable then likely to be displaced (not always – opposing occlusion can prevent displacement)
- Opposing occlusion
- Magnitude of force
- Mechanism of injury – single/multiple/size
- Intact soft tissue – intact ->unlikely
- Other associated fractures – more=higher displacement chance
3 stages in management of mandibular fractures
clinical examination
radiographic assessment
tx
radiographic assessment of manidbular fractures must involve
parallax
Two radiographs at right angle to each other (OPT +PA mandible)
Other radiographs
a. Occlusal
b. Lateral oblique
c. Town’s view (subcondylar)
d. SMV
e. CT scans – mainly now or CBCT (3D images best)
describe fractures here
2
right site #, step deformity – right parasymphseal fracture (compound)
left # - angle to coronoid process (likely simple)
any fracture around teeth bearing area is a compound fracture as in direct communication with PDL (and thus gingival crevice)
* need Antibiotics for management
3 radiographic characteristic features
to comment on
displacement
step deformity
radiolucent
tx steps of mandibular fractures
control of pain and infection - antibiotics and NSAIDs
2 basic prinicples - reduction and fixation
* undisplaced # = no tx needed
* displaced or mobile # = fixation (surgical intervention)
reduction
reduce the displacement to its normal anatomical orientation of the # segments (only for displaced fractures)
fixation
fix in place, commonly plates and screws (internal fixation)
options for displaced/mobile #
2
closed reduction and fixation (IMF)
open reduction and internal fixation (ORIF)
closed reduction and fixation
Reduce the fracture segment to normal anatomical orientation without exposure of fracture line
* No periosteal exposure of fracture
Use other guides – e.g. intermaxillary fixation (teeth in occlusion) – need to wire teeth together
* Usually have wear facets to guide you
* Hard to maintain OH
* Soft diet for 6 weeks
ORIF (open reduction and internal fixation)
reflect soft tissue and expose bone
used mainly now
Exposure of #, reduce with eyes, fix with plates and screws (no need for wiring)
Plates 2mm, screws 5mm
* Kept permanently inside pt mouth
issue in osteoporoitic #
bone very thin, unable to apply a plate – need a bone graft (harvest from ribs)
can use resorbable metals – polylactic acid, malleable in hot water to adapt to bone and then fix
indications for ORIF
5
Bilateral subcondylar fracture with anterior open bite tendency
Displaced condylar fracture that interferes with mouth opening
Displaced fracture in the middle cranial fossa
Displaced fracture that causes occlusal derangement
Displaced fracture that causes ramus shortening
fixation by
plates (semi rigid or rigid)
Interosseous wiring
Upper/lower border
Cortical
Transosseous, circumferential
Screws
Pins/K wires
primary Bone grafting
fixation by
plates (semi rigid or rigid)
Interosseous wiring
Upper/lower border
Cortical
Transosseous, circumferential
Screws
Pins/K wires
primary Bone grafting
6 complication of mandibular #
Loss of teeth (loosening)
Delay of union – local infection (plates)
* Mobility of fragment
* Poor reduction
* Soft tissue interposition
* Local pathology
* Old age/debility
* Systemic disease
Malunion
Non union
Late onset trismus
Persisting mental anaesthesia
9 complications of condylar fractures
Trismus – clicking and locking
Osteoarthritis
Subluxation
Late trismus
Deviation to affected side
Ankylosis and asymmetry
Open bite
Neurological – auriculotemp syndrome
* Mandibular anaesthesia
* VII nerve paresis
Vascular – aneurysms e.g. carotid
tx for hairline cracks
condyle #
none
tx for dentate pts
condyle #
interdental eyelet wings, metal arch bars, silver cap splints
avoid surgical intervention for condyle #
tx for edentulous pts
condyle #
modified dentures, Gunning’s splints
reduction and fixation
avoid surgical intervention for condyle #
