Mandibular Fractres(1)

7/31/2019 Mandibular Fractres(1)

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Maxillofacial Trauma

Mandibular 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 traumaMandibular fracture is more common than middlethird fracture (anatomical factor)

It could be observed either alone or in combinationwith other facial fractures

Minor mandibular fracture may be associated withhead injury owing to the cranio-mandibulararticulation

Mandibular fracture may compromise the patency ofthe airway in particular with loss of consciousness

Fracture of mandible occurred with frontal impactforce as low as 425 lb (190 Kg) {Condylar fracture}


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Fracture of condyle regarded as a safety mechanismto the patient

Frontal force of 800-900 lb (350-400 Kg) is requiredto cause symphesial fracture

Mandible was more sensitive to lateral impact thanfrontal one

Frontal impact is substantially cushioned by openingand retrusion of the jaw

(Nahum 1975)

Long canine tooth and partially erupted wisdomsrepresent line of relatively weakness


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Anatomical considerations

Attached muscles:

Masseter

Temporalis

Medial and lateralpterygoid

Mylohyoid

Geniohyoid andgenioglosus

anterior belly ofdigastrics


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Blood supplyEndosteal supply via the ID artery and vein

Periosteal supply, important in aging due todiminishes and disappearance of alveolarartery

Bradley 1972

NerveDamage of inferior dental nerve

Facial palsy by direct trauma to ramus

Damage of facial nerve in temporal bonefracture

Goin 1980

Damage to mandibular division of facialnerve


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Factors influenced site of fracture

and displacementAnatomy of themandible and attachedmuscle (canine &wisdoms)

Weakening areas ofmandible (resorptionand pathologyl)

Direction of force of theblow

Age of the patient


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Types of fractureSimple

Greenstick fracture (rare, exclusively in children)Fracture with no displacement (Linear)Fracture with minimal displacement

Displaced fracture

Comminuted fractureExtensive breakage with possible bone and soft tissue

loss

Compound fractureSevere and tooth bearing area fractures

Pathological fracture(osteomyelities, neoplasm and generalized skeletal

disease)


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Sites of fracturesCondyle fracture

Intracapsular fracture

Extracapsular fractureHigh condyle neck fracture

Low condylar fracture

Angle/ ramus fracture (bodyfracture)

Canine region (parasymphesial

fracture)

Midline fracture (symphesisfracture)

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 orunfavourable

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 theunopposed action of medial pterygoid muscle, theposterior fragment will be pulled linguallyIf the horizontal direction of the fracture favours theunopposed action of messeter and pterygoid muscles in

upward direction, the posterior fragment will be pulledlingually

Favourable fracture line makes the reducedfragment 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 tooverlap under the influence of muscles action

Bilateral parasymphesial fracture results inbackward 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 andfracture of petrous temporal bone

which is very rare


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Sign and symptoms

Swelling, pain, tenderness and restriction of movement

Deviation of mandible towards the side of fracture

Gagging of occlussion (premature contact on the posteriorteeth) 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 basefracture

Condylar fractures


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Sequlae of TMJ injury

Artheritic changes

Haemartherosis, fibrosis and aknylosis

Meniscal damage and detachment

TMD

Staph infectionwith condylar backward

displacement and external auditory meatus injury

Meningitiswith petrous temporal bone fracture andintracranial involvement

Condylar fractures


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Coronoid process fracture:

Rare fracture caused by direct trauma toramus and results from reflux contraction oftemporalis

Can be seen following operation of largeramus cyst

Elicit tenderness over the anterior part oframus

Development of tell-tale haematoma


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Fracture of the ramus:

Type I Single fractureMimics low condylar fracture that runsbelow the sigmoid notch

Type II comminuted fracture

Common in missile injuries and appears tobe with little displacement due to effects ofmesseter and medial pterygoid muscles


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Fracture of the angle and bodyPain, tenderness and trismus

Extra-oral swelling at the angle with obviousdeformity

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 longitudinalsplit fracture


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Midline fractureThe most common missed fracture (always

fine crack)

Can be symphesial or parasymphesialfracture

Commonly associated with one or bothcondyles fracture

Unilateral fracture leads to over-riding ofthe fragments and bilateral may contributein loss of voluntery tongue control

Long canine tooth represent a weak areaand contributes to parasymphesial fracture

Rarely runs across mental foramen

Midli f t


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Signs and symptoms

Pain and tendernessSwelling and odemeaDevelopment of step deformityMental anesthesiaHeamatoma 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 mandibleAnterior open biteGagging of oclussionLimitation of mouth opening

Midline fracture


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Clinical assessment and diagnosis

History of trauma(traumatized patients with possible head injury) and facialinjuries

Clinical ExaminationExtroral

Inspection (assessment of asymmetery, swelling, ecchymosis, lacerationand cut wounds)

Palpation for eliction of tenderness, pain, step deformity and malfunction

Intra- and paraoral

bleeding, heamatoma, gingival tear, gagging of occlussionand step deformity and sensory and motor deficiency

Radiographs


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Radiographs

Plain radiographOPG

Lateral oblique

PA mandible

AP mandible (reverse

Townes)

Lower occlusal

CT scan

3-D CT imaging

MRI
http://www.srt-psc.com/jfmand2.jpghttp://www.srt-psc.com/jfmand4.jpghttp://www.srt-psc.com/jfmand2.jpg


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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 immobilizationOpen reduction and rigid fixation

Other objective of mandible fracture treatment:Control of bleeding

Control of infection

Definiti e treatment


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Definitive treatmentSoft tissue repair

Debridment

Irrigation with saline and antibioticsClosure in layers

Dressing

Reduction and fixation of the jaw

Close reduction and IMF (traditional method by means ofmanipulation)

Open reduction and semi-rigid fixation (using inter-ossouswirings)

Open reduction and rigid fixation (using bone palatesosteosynthesis)

Objective:Restoration of functional alignment of the bone fragments inanatomically precise position utilizing the present teeth for

guidance


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Close reduction

Bonded brackets

IMF screws

Dental wiring:

Direct wiring

Eyelet wiring

Local anesthesia orsedation

Minimal displacementIMF for 6 weeksTreatment can be performedunder GA or LA and when

surgery is contraindicated
http://www.srt-psc.com/%20wjnpos.jpg


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Fracture mandible in children

Close reduction

Open reduction and

fixation

Plating at the inferiorborder

Resorpable plates
http://www.srt-psc.com/ca2.jpghttp://www.srt-psc.com/ca3.jpg


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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
http://www.srt-psc.com/ael.jpg


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Rigid fixation

Intraossous wiring

Plates and screws

Kirchener wire

Lag screws
http://www.srt-psc.com/drfx1po.jpg


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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 approachPreauricular 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 itsblood supply

The tooth may be affected by somepreexisting 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

infectedFollow up for 1 year and endodontic therapy if

there is a loss of vitality


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Absolute indicationsLongitudinal fracture

Dislocation or subluxation from socket

Presence of periapical infection

Infected fracture line

Acute pericoronitis

Relative indicationsFunctional tooth that would be removed

Advanced caries or periodontal diseases

Doubtful tooth which would be added to existingdenture

Tooth in untreated fracture presenting more than 3days after injury


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Mandibular Fractres(1)

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