Maxillofacial Trauma Mandibular Fractures

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Maxillofacial TraumaMandibular Fractures
Mandible is embryologically a membrane bent bone
although, resembles physically long bone it has
two articular cartilages with two nutrient
arteries
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Mandible in trauma

• Mandibular fracture is more common than middle
  third fracture (anatomical factor)
• It could be observed either alone or in
  combination with other facial fractures
• Minor mandibular fracture may be associated with
  head injury owing to the cranio-mandibular
  articulation
• Mandibular fracture may compromise the patency of
  the airway in particular with loss of
  consciousness
• Fracture of mandible occurred with frontal impact
  force as low as 425 lb (190 Kg) Condylar
  fracture

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• Fracture of condyle regarded as a safety
  mechanism to the patient
• Frontal force of 800-900 lb (350-400 Kg) is
  required to cause symphesial fracture
• Mandible was more sensitive to lateral impact
  than frontal one
• Frontal impact is substantially cushioned by
  opening and retrusion of the jaw
• (Nahum 1975)
• Long canine tooth and partially erupted wisdoms
  represent line of relatively weakness

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Anatomical considerations

• Attached muscles
• Masseter
• Temporalis
• Medial and lateral pterygoid
• Mylohyoid
• Geniohyoid and genioglosus
• anterior belly of digastrics

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• Blood supply
• Endosteal supply via the ID artery and vein
• Periosteal supply, important in aging due to
  diminishes and disappearance of alveolar artery
• Bradley 1972
• Nerve
• Damage of inferior dental nerve
• Facial palsy by direct trauma to ramus
• Damage of facial nerve in temporal bone fracture
• Goin 1980
• Damage to mandibular division of facial nerve

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Factors influenced site of fracture and
displacement

• Anatomy of the mandible and attached muscle
  (canine wisdoms)
• Weakening areas of mandible (resorption and
  pathologyl)
• Direction of force of the blow
• Age of the patient

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Types of fracture

• Simple
• Greenstick fracture (rare, exclusively in
  children)
• Fracture with no displacement (Linear)
• Fracture with minimal displacement
• Displaced fracture
• Comminuted fracture
• Extensive breakage with possible bone and soft
  tissue loss
• Compound fracture
• Severe and tooth bearing area fractures
• Pathological fracture
• (osteomyelities, neoplasm and generalized
  skeletal disease)

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Sites of fractures

• Condyle fracture
• Intracapsular fracture
• Extracapsular fracture
• High condyle neck fracture
• Low condylar fracture
• Angle/ ramus fracture (body fracture)
• Canine region (parasymphesial fracture)
• Midline fracture (symphesis fracture)
• Coronoid fracture (rare)

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Incidence of mandibular fractures

• Body fractures 33.6
• Subcondylar fracture 33.4
• Fractures at the angle 17.4
• Alveolar fractures 6.7
• Ramus fractures 5.4
• Midline fractures 2.9
• Fracture of coronoid process 1.3
• Oikarinen Malmstrom 1969

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Favourable or unfavourable

• They can be vertically or horizontally in
  direction
• They are influenced by the medial
  pterygoid-masseter sling
• If the vertical direction of the fracture favours
  the unopposed action of medial pterygoid muscle,
  the posterior fragment will be pulled lingually
• If the horizontal direction of the fracture
  favours the unopposed action of messeter and
  pterygoid muscles in upward direction, the
  posterior fragment will be pulled lingually
• Favourable fracture line makes the reduced
  fragment easier to stabilize

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Effects of muscles on displacement

• Transverse midline fracture (symphesial)
  stabilizes by the action of mylohyoid and
  geniohyoid
• Oblique fracture (parasymphesial) tends to
  overlap under the influence of muscles action
• Bilateral parasymphesial fracture results in
  backward displacement associated with loss of
  tongue control when the level of consciousness is
  depressed

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Condylar fractures

• The most common mandibular fracture
• Unilateral or bilateral
• Intracapsular or extracapsular
• Antero-medial displacement is common but it may
  remain
• angulated with the ramus
• Dislocation of the glenoid fossa and fracture of
  petrous temporal bone which is very rare

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Sign and symptoms
Condylar fractures

• Swelling, pain, tenderness and restriction of
  movement
• Deviation of mandible towards the side of
  fracture
• Gagging of occlussion (premature contact on the
  posterior teeth) with bilateral condylar
  displaced or over-riding fractures
• Displacement of mandible toward the affected side
• Anterior open bite on opposite side of fracture
• Laceration of EAM
• Retroauricular ecchymosis
• Cerebrospinal leak and otorrhea in association
  with skull base fracture

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Sequlae of TMJ injury
Condylar fractures

• Artheritic changes
• Haemartherosis, fibrosis and aknylosis
• Meniscal damage and detachment
• TMD
• Staph infection with condylar backward
  displacement and external auditory meatus injury
• Meningitis with petrous temporal bone fracture
  and intracranial involvement

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• Coronoid process fracture
• Rare fracture caused by direct trauma to ramus
  and results from reflux contraction of temporalis
• Can be seen following operation of large ramus
  cyst
• Elicit tenderness over the anterior part of ramus
• Development of tell-tale haematoma

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• Fracture of the ramus
• Type I Single fracture
• Mimics low condylar fracture that runs below
  the sigmoid notch
• Type II comminuted fracture
• Common in missile injuries and appears to be
  with little displacement due to effects of
  messeter and medial pterygoid muscles

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Fracture of the angle and body

• Pain, tenderness and trismus
• Extra-oral swelling at the angle with obvious
  deformity
• Step deformity behind the molar teeth
• Movement and crepitus at the fracture site
• Derangement of occlussion
• Intra-oral buccal and lingula heamatoma
• Involvement of IDN
• Gingival tear if fracture in dentated area
• Tooth involvement and possible longitudinal split
  fracture

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Midline fracture

• The most common missed fracture (always fine
  crack)
• Can be symphesial or parasymphesial fracture
• Commonly associated with one or both condyles
  fracture
• Unilateral fracture leads to over-riding of the
  fragments and bilateral may contribute in loss
  of voluntery tongue control
• Long canine tooth represent a weak area and
  contributes to parasymphesial fracture
• Rarely runs across mental foramen

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Signs and symptoms
Midline fracture

• Pain and tenderness
• Swelling and odemea
• Development of step deformity
• Mental anesthesia
• Heamatoma in the floor of mouth and buccal mucosa
  
• Soft tissue injury of the chin and lower lip
• If associated with condylar fractures
• Absence of condyle movement on the contrlateral
  side
• Deviation of mandible
• Anterior open bite
• Gagging of oclussion
• Limitation of mouth opening

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Clinical assessment and diagnosis

• History of trauma
• (traumatized patients with possible head
  injury) and facial injuries
• Clinical Examination
• ? Extroral
• Inspection (assessment of asymmetery, swelling,
  ecchymosis, laceration and cut wounds)
• Palpation for eliction of tenderness, pain, step
  deformity and malfunction
• ? Intra- and paraoral
• bleeding, heamatoma, gingival tear,
  gagging of occlussion and step deformity and
  sensory and motor deficiency
• Radiographs

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Radiographs

• Plain radiograph
• OPG
• Lateral oblique
• PA mandible
• AP mandible (reverse Townes)
• Lower occlusal
• CT scan
• 3-D CT imaging
• MRI

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Principles of treatmentsimilar to elsewhere
fractures in the body

• Reduction of fragments in good position
• Immobilization until bony union occurs
• These are achieved by
• Close reduction and immobilization
• Open reduction and rigid fixation
• Other objective of mandible fracture treatment
• Control of bleeding
• Control of infection

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Definitive treatment

• Soft tissue repair
• Debridment
• Irrigation with saline and antibiotics
• Closure in layers
• Dressing
• Reduction and fixation of the jaw
• ? Close reduction and IMF (traditional method by
  means of manipulation)
• ? Open reduction and semi-rigid fixation (using
  inter-ossous wirings)
• ? Open reduction and rigid fixation (using bone
  palates osteosynthesis)
• Objective
• Restoration of functional alignment of the
  bone fragments in anatomically precise position
  utilizing the present teeth for guidance

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Close reduction

• Arch bars
• Jelenko
• Erich pattern
• German silver notched
• Cap splints
• ? IMF prior to rigid fixation
• ? For the purpose of close reduction

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Close reduction

• Bonded brackets
• IMF screws
• Dental wiring
• Direct wiring
• Eyelet wiring
• Local anesthesia or sedation
• Minimal displacement
• IMF for 6 weeks
• Treatment can be performed under GA or LA
  and when surgery is contraindicated

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Fracture mandible in children

• Close reduction
• Open reduction and fixation
• Plating at the inferior border
• Resorpable plates

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Gunnings splint

• Old modality
• Edentulous patient
• Rigid fixation is not possible
• To establish the occlusion

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Open reduction and fixation

• Intraoral approach
• Extraoral approach
• ? Submandibular approach

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Rigid fixation

• Intraossous wiring
• Plates and screws
• Kirchener wire
• Lag screws

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Reconstruction palate
Severe trauma Loss of part of the bone
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Condylar fractures

• Intraoral approach
• Ramus incision
• Extraoral approach
• Preauricular approach
• Retromandibular approach

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IMF

• Transosseous wiring
• Circumferential wiring
• External pin fixation
• Bone clamps
• Trans-fixation with Kirschner wires

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Osteosynthesis

• Non-compression small plates
• Compression plates
• Miniplates
• Lag screws
• Resorbable plates and screws

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Teeth in the fracture line

• The fracture is compound into the mouth
• The tooth may be damaged or lose its blood supply
• The tooth may be affected by some preexisting
  pathology

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Management of teeth retained in fracture line

• Good quality intra-oral periapical radiograph
• Insinuation of appropriate systemic antibiotic
  therapy
• Splinting of tooth if mobile
• Endodontic therapy if pulp is exposed
• Immediate extraction if fracture becomes infected
• Follow up for 1 year and endodontic therapy if
  there is a loss of vitality

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• Absolute indications
• Longitudinal fracture
• Dislocation or subluxation from socket
• Presence of periapical infection
• Infected fracture line
• Acute pericoronitis
• Relative indications
• Functional tooth that would be removed
• Advanced caries or periodontal diseases
• Doubtful tooth which would be added to existing
  denture
• Tooth in untreated fracture presenting more than
  3 days after injury

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Any question