zygomatico maxillary complex fracture

ZYGOMATICO MAXILLARY COMPLEX FRACTURE

CONTENTS

Introduction Fracture pattern Classification Clinical features Investigation Management Surgical Approaches Reduction Fixation Complication References

INTRODUCTION Zygoma is a major buttress of facial

skeleton is the principle structure of lateral midface.

It is equivalent of a four sided pyramid. It has temporal process which

articulates with temporal bone, maxillary process which articulates with maxillary bone and frontal process which articulates with frontal bone.

Fracture of zygoma is usually not present alone, it finds mostly in conjunction with adjacent structures i.e., antrum, orbital floor. This structure makes up the zygomaticomaxillary complex.

FRACTURE PATTERN

Fracture pattern follows a line which commence at frontozygomatic suture, passes downward close to or between the greater wing of sphenoid and the frontal process of zygomatic bone to reach anterior limit of inferior orbital fissure and then turns anteromedially to cross the inferior orbital margin above or in close proximity to the infraorbital canal.

From this point the fracture continues inferolaterally to cross the outer wall of antrum and pass beneath the zygomatic buttress turning upward across the posterior wall of antrum to rejoin the anterior limit of inferior orbital fissure.

Inferior orbital fissure is the key to remembering the usual lines of zygomaticomaxillary complex fracture 3 lines extending from inferior orbital fissure in 3 direction-anteromedially

superolaterally inferiorly

One fracture line extend from inferior orbital fissure anteromedially along orbital floor mostly through orbital process of maxilla towards the infraorbital rim.

Second line of fracture run from inferior orbital fissure to inferiorly towards the posterior aspect of maxilla(infra temporal)and joins the fracture from the anterior aspect of maxilla under the zygomatic buttress.

Third line of fracture extend superiorly from the inferior orbital fissure along the lateral orbital wall posterior to the rim, usually separating the zygomatico sphenoid suture.

An additional fracture line runs through the zygomatic arch.

frequently ; however 3 fracture lines exist through the arch, producing 2 free segments when the fracture are complete.

CLASSIFICATION

I. Row and Killey classification(1968)Type I – no significant displacementType II – Fracture of zygomatic archType III – rotation around vertical axis (inward or

outward displacement)Type IV – rotation around longitudinal axis(medial or

lateral displacement)Type V – displacement of complex blocType VI – displacement of orbitoantral partitionType VII – displacement of orbital rim segmentType VIII – complex comminuted fractures

II.Larsen & Thomsan classification

GROUP A: stable fracture-showing minimum or no displacement, requires no treatment.

GROUP B: unstable fracture-great displacement & disruption of frontozygomatic suture & comminuted fractures , require reduction & fixation.

GROUP C: stable fracture-types of zygomatic fracture which require reduction but no fixation.

III. FRACTURE OF THE ZYGOMATIC ARCH NOT INVOLVING THE ORBIT

Minimum or no displacement Comminuted fracture V-type in fracture W-type fracture

CLINICAL FEATURES SKELETAL

DEFORMITIES› Asymmetry of the

mid face› Depression or

flattening of malar prominence

› Flattening , hollowing or broadening over the zygomatic arch

› Step deformity of orbital margins

OCULAR /OPHTHALMIC SYMPTOMS› Periorbital edema› Downward slant of palpebral fissure› Malposition of the lateral canthus › Vertical shortening of the lower eye lid

› Subconjunctival ecchymosis› Hypoglobus› Enophthalmos› Exophthalmos

DIPLOPIA:• Diplopia is a very common complication of

the zygomatic fracture where patients experiences blurred double vision.

• Types of diplopia: - temporary & permanent - monocular & binocular

Causes of diplopia Haematoma or oedema around the extraocular

muscles. Disruption in the attachments of inferior rectus

or inferior oblique muscle causes displacement of muscle attachment.

Orbital floor fracture which leads to herniation of the periorbital fat into the maxillary sinus.

Neuromuscular injury resulting in paralysis of the muscle.

Fibrous tissue formation & adhesion between the globe & orbital floor.

TEST FOR DIPLOPIA1. Finger gaze:- Finger moved infront of eye in all nine directions of gaze at a distance of

30cm.2. Forced duction test:- - Diplopia caused due to oedema or hematoma of the extraocular muscles resolves in 5 to 7 days but diplopia as a result of failure to rotate the eyes superiorly indicates paralysis or muscle entrapment within the fracture segment.

- To differentiate these 2 causes force duction test/ traction test is carried out under topical anaesthetic with the tissue holding forcep hold the tendon of the inferior rectus muscle & rotate the eyeball superiorly with other movements.

- A failure to rotate eyes superiorly indicates paralysis or entrapment of muscle within the fracture segment.

HESS DIPLOPIA CHART (LEES SCREEN ) :- Helps in identifying the nonfunctioning extraocular muscle- In this test, dissimilar images are projected for each eye

at 1 metre distance with the patient wearing green or red goggles.

- A red test object is held against a screen & the patient tries to indicate the position of the object by touching it with a green tipped wand.

- The result of pt. effort is charted when pt. head is held still & pt. moves pt. eyes from the primary position to the horizontal right & left extremes of movements.

- This is repeated when looking above, & left above.- The equivalent lower positions are also charted.

DIPLOPIA CHART :- This can be a simple useful tool for

diagnosis of diplopia especially in the absence of a Hess chart.

- Vertical bar of light is viewed through red & green goggles at a fixed distance from the eye.

- The bar light is moved into each direction of gaze & the pt. describes the image separation & appearance.

FIELD OF BINOCULAR SINGLE VISION (BSV) :- Used to describe the area of BSV, & hence diplopia.- The pt. is seated at the perimeter, with the chin

central to fixation.- The target is moved outwards until the pt.

recognises diplopia & the point is marked.- The target is then moved further until one image

disappears, normally due to occlusion by facial contours & this point is marked.

- The inner ring describes the area of BSV ; the outer ring describes the limits of the binocular field of fixation.

NEUROLOGICAL SYMPTOMS› Paresthesia of infraorbital nerve › Parethesia of supra orbital and supra

trochlear nerve› Paresthesia of zygomatico temporal and

zygomatico facial nerve› Paralysis of facial nerve› Paralysis of extraocular muscles

ORAL SYMPTOMS› Ecchymosis in the buccal sulcus of maxillary

arch› Deformity of zygomatic buttress of maxilla› Trismus› Pain› Impacted /flattened zygomatic arch

NASAL SYMPTOMS› Ipsilateral epistaxis › Ipsilateral hematosinus

INVESTIGATIONS Plain radiographs water’s view or paranasal view of

zygomaticomaxillary complex fracture,floor of orbit,infra orbital rim

submentovertex- Arch fracture CT scan

WATERS VIEW

SUBMENTOVERTEX VIEW

MANAGEMENT Surgical approach:-

A. Extra oral approach Gillies temporal fossa approach Suprolateral

Supraorbital approach; lateral eyebrow Upper eyelid

Lower eyelid Infra orbital Subtarsal Subcilliary

Transconjunctival Percutaneous Bicoronal/ hemicoronal

B. Intra oral approach Transoral/ keen’s approach Endoscopic transantral approach

Gillies temporal fossa approach(1927)

An incision about 2.5cm length is made between the two branches of the superficial temporal artery at an angle of 45˚ to the upper limit of the attachment of the external ear.

Dissection is carried out till the temporal fascia. A Bristow’s elevator is passed down through this incision beneath the zygomatic bone which is then gradually reduced to its position.

The incision is then closed in layers. Rowe pattern zygomatic elevator is

also used in this approach for the reduction of the zygomatic fracture.

Bristow’s elevator has a disadvantage of using the temporal bone as fulcrum causing risk of fracturing the temporal bone during the procedure. This was overcome by the design in Rowe zygoma elevator.

Transoral/ keen’s approach/ Balasubramaniam approach/ Transverse buccal sulcus incision :

Also known as lateral maxillary vestibular incision

A bone hook can be passed from a transverse incision made in the region of buccal sulcus and the fractured segment can be reduced.

An incision 1cm in length is made in the buccal sulcus behind the zygomatic buttress.

A bone hook or curved elevator is passed behind supraperiosteally, to contact the deep part of the zygomatic bone. Here an upward, outward and forward pressure is exerted.

The advantage of this method is that less amount of force is required for reduction.

Bicoronal/ hemicoronal approach

The zygoma fracture reduction is complete if the sphenozygomatic suture is reduced. This suture can be visualized only by this approach. Moreover, this approach is ideal in zygomatic complex fracture involving the frontal bone, orbital roof reconstruction, arch fracture requiring fixation and laterally displaced zygoma fracture requiring 3 or 4 point fixation.

FIXATION TECHNIQUES› 1 point fixation› 2 point fixation› 3 point fixation› 4 point fixation

One point fixation› Indication

- Undisplaced fracture at frontozygomatic suture- Simple non comminuted zygomatic complex

fracture› Approach

- Frontozygomatic suture approached through supraorbital eyebrow approach.

- Zygomaticomaxillary buttress approached through maxillary vestibular approach.

- One point fixation with miniplates in the zygomaticomaxillary butress region can avoid unsightly scars and give high satisfaction with surgical outcome in selected patients with zygoma fractures.

Two point fixation› Indication

- Displaced fracture unstable after reduction- Fracture at frontozygomatic suture, infraorbital

rim and buttress.› Approach

- Exposure of frontozygomatic suture through lower eyelid incision or maxillary vestibular incision.

- A 2 point fixation using low profile plate at zygomaticomaxillary buttress or at the infra orbital rim suffice.

Three point fixation› Fixation is done at frontozygomatic

suture,zygomaticomaxillary buttress and the infraorbital rim.

› Good reduction of these 3 sites mostly reduces the arch fracture which is not fixed.

Four point fixation› Unique from 3 point technique in that the

surgeon visualizes the zygomatic arch. The order of placement of the plates will be dependant on the least damaged landmarks. The zygomatic arch is an excellent reference to restore proper anteroposterior projection of the midface.

Fixation is again of two types:i. Direct fixation

- Transosseous wiringii. Indirect fixation

- Internal pin fixation- Transfixation with kirschner wire

COMPLICATIONS Complication of periorbital incision Infraorbital nerve paresthesia Implant extrusion/displacement and infection Persistent diplopia Enophthalmos Blindness Retrobulbar hemorrhage Ankylosis of zygoma to coronoid Malunion Orbital dystopia