MANDIBULAR INJURIES
DISLOCATION:
Anterior
Extreme opening eg yawn/laughter, large bite, oral sex, GA, tonsillectomy
Other types
Require traumatic injury
Muscle spasm then traps mandible out of position
Temporalis, pterygoid, masseter
Risks:
Shallow glenoid fossa
Increased muscle tone (including dystonic reactions)
Loss of joint capsule (previous trauma)
Hyper-mobility: Marfan’s, Ehlers-Danlos
Unilateral – jaw deviates to opposite side
Bilateral – more common
Anterior – most common
Posterior – rare, direct blow, condylar head may prolapse into ext auditory canal
Lateral – often associated with #
Superior – blow to partially open mouth, condylar head  upward, assoc with
cerebral contusions, facial nerve palsy, deafness
Clinical:
Pain
Mal-occlusion
Drooling
Speech/swallowing difficulty
Unilateral – jaw deviates to opposite side (NB bilateral more common)
Anterior: pre-auricular depression
Posterior – examine ext auditory canal, check hearing
Lateral- always signs of #
Superior – check for head/neck/CNS injury
Investigations
Spontaneous, anterior, atraumatic – clinical Dx
OPG usually suffices
More trauma/suspicion of head injury – CT
DDx
Fracture
Haemarthrosis TMJ
Locking of TMJ
TMJ dysfunction
Complications:
Recurrent dislocation
Ear/auditory canal injuries
C-spine/head injuries
Dental injuries
Nerve injuries – facial, mandibular
Treatment: (after # excluded0
Analgesia
Reduction under sedation
Can try: Local anaesthetic injected into joint space
2ml of 2% lignocaine
Reduction:
1) Sitting:
Gloved thumbs over molars, fingers supporting body
Downward & backward pressure, slight opening may help
2) Supine
Standing behind patient
Gloved thumbs over molars, fingers supporting body
Downward & backward pressure
May wrap gauze around thumbs in case masseter spasm causes clenching on
reduction
Post-reduction xrays not required if
Atraumatic reduction
Able to open/close mouth without significant pain
Complications of reduction – rare
Fracture
Avulsion of articular cartilage
Disposition:
Uncomplicated Anterior
Discharge post reduction
Soft diet for 2 weeks (& Avoid opening mouth > 2cm)
Support mandible with hand when yawning
NSAIDS
Maxillofacial review as outpatient
Recurrent dislocations may require operation
Comlications:  refer to Facio-maxillary surgeon urgently
Open
Superior
Fracture
Nerve injury
Irreducible
FRACTURE
Usually traumatic – assaults/falls
2nd most common facial fracture (after nose)
Ring shape – often multiple #’s
Associated injuries:
Head/c-spine
# temporal bone
) from transmitted force
Perforated eardrum )
Dental injuries
Nerve injuries – facial, mandibular
Clinical:
Pain
Mal-occlusion
Drooling
Gingival lacerations (may be hidden between teeth)
Ecchymosis under tongue – sensitive for mandible #
Signs of associated injuries – dental, nerve, head, c-spine
Investigations
OPG: Orthopantomogram
PA/oblique xrays
“Towne view” xray – limited to condyle/neck
CT – if high suspicion but xrays NAD (especially condylar #)
Treatment:  consult with Facio-Max
Open Fractures
Admission
IV antibiotics
Closed fractures
May be Mx as outpatients