ZYGOMATIC (MALAR) FRACTURES133 Chapter 12 ZYGOMATIC (MALAR) FRACTURES INVESTIGATIONS — Imaging Fig. Plain occipitomental (OM) view demonstrating a low energy Henderson type 4 fracture.

$Page 1: ZYGOMATIC (MALAR) FRACTURES133 Chapter 12 ZYGOMATIC (MALAR) FRACTURES INVESTIGATIONS — Imaging Fig. Plain occipitomental (OM) view demonstrating a low energy Henderson type 4 fracture.$
ZYGOMATIC (MALAR)FRACTURES

129

CH

AP

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R 1

2

All fractures of the zygoma potentiallyinvolve the orbital floor.

Minor discrepancies of zygomatic boneposition can cause marked asymetry.

Anatomical articulations

FZ — Fronto-zygomatic

ZT — Zygomatico-temporal

ZMB — Zygomatico -maxillary buttress

IO — Infraorbital

Forms the lateral part of the orbit Provides lateral facial projectionProtects the globe

The zygomatic bone transmits 3 nerves

InfraorbitalZygomaticofacialZygomaticotemporal

Anatomical articulation

ZS — Zygomaticospenoid

Zygomaticosphenoid junction is akey articulation when there is grosscomminution of the other fracturearticulations.

Useful in cases of revision trauma.

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An Atlas of Craniomaxillofacial Trauma

ClassificationThere are several classifications of lateral facial fractures, the Henderson classifi-cation is the most useful.

Henderson Classification Description

Type 1 Undisplaced

Type 2 Zygomatic arch

Type 3 Tripod fracture — Intact FZ suture

Type 4 Tripod fracture — Distracted FZ suture

Type 5 Associated orbital floor fracture

Type 6 Orbital rim fracture

Type 7 Comminuted and other fracture

Fig. ‘Tripod fracture’ of zygoma.

Note fracture of zygomaticotemporalarticulation (arrow).

Fig. Same fracture.

Note displacement at the zygomaticofrontaljunction, zygomaticomaxillary buttress, andinfraorbital margin.

Of significance is the comminution of theinfraorbital margin which complicatesfracture management, and implies an orbitalfloor extension.

Zygomatic injuries may bepart of a wider and morecomplex pattern, alwaysexclude other fractures.


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Chapter 12 ZYGOMATIC (MALAR) FRACTURES

CLINICAL FEATURES

Clinical Features Signs and Symptoms

Soft tissue Periorbital ecchymosisSubconjunctival haematomaChemosisBuccal Sulcus haematoma

Bone deformity Flattening of malar prominenceStep deformityCrepitusZygomatic arch depression

Eyes DiplopiaEnophthalmosIf associated orbital floor fracture

Nerves Infraorbital paraesthesia anaesthesiaZygomaticotemporal paraesthesiaZygomaticofacial paraesthesiaAlveolar nerve anaesthesia

Nasal EpistaxisNasal deformity (if fracture continuous with nose)

Occlusal Trismus (zygomatic arch)Occlusal disturbance (if fracture extends into alveolar process)

Fig. Classic ‘zygomatic facies’, periorbital ecchymosis.

Associated soft tissue swelling may make examination ofthe globe difficult.

Bone deformity and asymmetry may be demonstrated bycareful palpation.

Remember to always examine the globe.

Visual acuity and globe integrity mustbe documented.


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Fig. Preseptal haematoma iscommon.

Fig. Subconjunctival haemorrhage ispathognomonic of a fracture around the orbit.

Fig. Fractured zygomatic arch.The small dent (black arrow) maynot be initially apparent and maybe masked by soft tissue swelling.

Limitation mouth opening andpain may be the only symptoms.

There are no eye signs ornumbness of the infraorbital nerve.


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INVESTIGATIONS — Imaging

Fig. Plain occipitomental (OM) viewdemonstrating a low energy Hendersontype 4 fracture.

Note the diastasis at the fronto-zygomaticsuture. This makes the fracture unstable.

Fig. OM 15 showing distraction at FZ,MB, and ZT articulations.

Fig. OM 30 of same fracture.

Note additional detail at lateral aspect ofinfraorbital margin (single arrow).

Also the distance between the coronoidprocess and the arch of zygoma is reducedon fracture side (left side).


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CT ScanFig. Considerable information can beobtained from CT images. This axialview shows the typical result of highenergy transfer. The force applied wasanterior posterior in direction (arrow) andthe zygomatic bone has rotated aroundthe temporozygomatic suture (TZ)resulting in a posteromedial displacement.There has been comminution of theorbital rim (COR) and an extendednasomaxillary fracture (NM). There arefragments of bone (OF) together withblood in the maxillary antrum, highlysuggestive of an additional orbital floorfracture.

Fig. Coronal view from the same caseconfirms the large orbital floor fracture(OF), with comminution of thezygomaticomaxillary buttress (ZMB). Thedistracted frontozygomatic suture (ZF) isalso demonstrated.

Fig. The sagittal view reveals thetrue extent of the orbital floorcomponent of the zygomaticfracture.

As the fracture is behind the equator ofthe eye enophthalmos is highly likely.

All zygomatic fractures will have an orbital floor component. Often this willbe insignificant, but if the floor is comminuted and/or deficient, then late(6 months plus) enophthalmos is probable.


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CT Scan — 3DFig. 3-Dimensional CT scans offer easyvisualisation and interpretation of complexinjuries, as in this extended zygomatic-craniofacial fracture.

Note the preservation of the inner margin ofthe zygomatic bone and sphenoid bone, thiswill simplify anatomical reduction.

Fig. Tripod fracture with grosscomminution. Distraction at 4 key points(arrow).

Note gross comminution. Infraorbitalarticulation required primary bone grafting.

Fig. Coronal scan showing grosscomminution of zygomaticomaxillarybuttress (large arrow).

FZ diastasis (small arrow).

Fig. Fractured zygomatic arch(white arrow).

This diagram also illustrates the inwardnature of the force which produced thefracture, the reverse of the directionrequired to reduce it.


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Management

Emergency

Preservation of visual acuityExclusion of ocular pathology Exclusion of retrobulbar haematoma

On Admission

AnalgesiaAntibioticSleep head upIce packs to reduce soft tissue swelling

Operative Planning

ImagingPlain filmLow energyIsolated zygomatic archCTHigh energySuspected orbital floor involvementComminution of fracture articulationModes of fracture reductionSites of osteosynthesisOther treatment options

Treatment Options

Non-operative management

• Undisplaced fracture• Medical or surgical comorbidity pre-

cluding operative surgery (see below)• No fracture mobility• No comminution of bony pillars• Sensible, competent patient• Able to attend regular follow-up

Sight threatening injuries arevery possible in zygomaticinjuries. Emergency managementand therefore prognosis isdependent upon early diagnosis.

CT should be considered in everyzygomatic fracture other than themost trivial. The exception is anuncomplicated arch fracture.

The decision not to operate isextremely patient-focused. Amalunited zygoma can cause asignificant asymmetry andsecondary reconstruction orcamouflage is a poor second toappropriate primarymanagement.


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Treatment Options

Operative management

— surgical access— reduction— fixation— post-operative management

Decision Making

Treatment planning the fractured zygomais perhaps the most confusing to theinexperienced surgeon.

Treatment MUST be fully plannedprior to surgery. There is no placefor taking a patient for theatreand ‘plating if it’s not stable’.

FZ — FrontozygomaticZT — ZygomaticotemporalPA — Piriform aperture (lateral

margin of nasal aperture)ZM — ZygomaticomaxillaryIO — Infraorbital

In treatment planning consider thezygoma as a starfish. The principleis to reconstruct the limbs of thestarfish (if they are fragmented)and then replace the zygoma to thecorrect anatomical position.

The reconstructed ‘starfish’ legsensure the correct position of thebone.


138

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Reduction

The aim of reduction is to replace thefractured and malpositioned bone intothe correct anatomical position.

The mode of reduction is designedto inversely mirror the force thatcaused the injury initially.

Approach Indication Comment

Temporal (Gillies Most displacements Excellent approachincision) Cosmetic unless alopecia

Elevation point remote from fixation point

Buccovestibular Medial and posterior Cosmeticdisplacements Difficult to position complex fracture

patternsDifficult if gross comminutionElevation point in field of fixation

Frontozygomatic Rare (if laceration present) Poor fulcrum(Dingman) Difficult to manouvre fragment

Point of elevation in field of fixationFZ incision frequently has to be extended

to accommodate elevator

Hook Posterior displacement Very good for posteriorMedial displacement Classically performed percutaneously

when point of access is remote fromfield of fixation

May be replicated by a transoral routealthough field of fixation is compromised


140


Bristow’s pattern Kilner pattern Rowe’s pattern

Fig. Zygomatic elevators.

Fig. Bone hook.


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Fig. Gillies temporal incision.Here the temporalis fascia isidentified. The zygomatic elevatoris passed under the fascia and sliddown under the zygomatic bone.

Fig. The frontozygomatic sutureis fixed with a 1.5 mm plate. Thisis a very useful point of fixation. Itmay be approached by a variety ofapproaches.

Fig. Surface marking forentrance point of zygomatic hook.A vertical line is drawn from thelateral canthus, and a horizontal linefrom the corner of the nose. Theintersection point marks the incisionpoint.

Fixation


142


Fig. Open zygoma fracture.

Note the bone graft (arrow) thiswas to make good a continuitydefect.

Fig. For complex zygomatic fractures,the coronal approach allows for extensivedegloving of the facial bones. Here thefractured zygoma is part of a wider fractureconfiguration.


143


Fig. Post-operativeradiographs of a complexzygomatic fracture.

Note fixation at FZ, IO,and ZM regions.

The need for 7 screwsat the FZ region was dueto the gross comminutionat that site.

The fixture at theinfraorbital site is a 1 mmlocalising plate. This is toensure that the patient doesnot feel the metalwork thusminimising the risk ofsubsequent plate removal.

Post-operative management

Imaging

Occipito mental view in no internalorbital reconstruction

CT scan if there is internal orbital workCT scan if reduction not considered

perfect intraoperatively CT scan if fragmentation of fracture

articulations

Medication

Dexamethasone peri- and post-operatively

Antibiotic therapy — continue for 5 daysAnalgesics — as required

Follow-up

Week 1 — removal of suturesWeek 3 — check bone and orbital

positionMonth 3 — final facial appearance

if indicated interval plate removal

Aesthetic and functional outcomeis dependent on soft tissue andorbital involvement.

Non-union is rare.

Malunion may require zygomaticosteotomy or medpore onlay.

Plate removal is unusual, althoughZM buttress plates may becomeexposed or be palpable.

Ensure dental follow-up.

Injured anterior teethcommonly observed withthese injuries.



ZYGOMATIC (MALAR) FRACTURES133 Chapter 12 ZYGOMATIC (MALAR) FRACTURES INVESTIGATIONS — Imaging Fig. Plain occipitomental (OM) view demonstrating a low energy Henderson type 4 fracture.

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