mid face fracture

Lufadeju

Introduction Epidemiology Anatomy of the mid face

Boundary Bones Physical characteristics Reinforcement Relevant nerves and blood vessels

Causes of mid face fractures Classification of mid face fractures Fracture lines

A fracture may be defined as a sudden break in the continuity of bone.

It may be complete or incomplete Fractures of the mid face are seen less

frequently than fractures of the mandible However, the incidence is increasing due

to increasing number of high speed transportation means.

The result of epidemiologic studies of mid face fractures differ with the population density, politics, era, socioeconomic status of the population reviewed, and the institution in which the survey was performed

Existing trends make it clear that mid face fractures are more frequently associated with motor vehicle and motorcycle accidents

Usually associated with other facial fractures and other injuries like lacerations, orthopedic and neurologic injury

Occur mostly in young men aged 16 to 40 years, especially between ages 21-25.

The risk of sustaining such fractures increases as the age of the patient increases

Boundaries- Superiorly – imaginary line drawn across the

skull from the zygomaticofrontal suture of one side, across the frontonasal and fronto maxillary sutures to the zygomaticofrontal suture on the other side

Inferiorly – the occlusal plane of the upper teeth. In an edentulous patient, the upper alveolar ridge

Posteriorly – sphenoethmoidal junction, including the free margin of the pterygoid laminae of the sphenoid bone inferiorly

Bones – 8 paired bones, 2 unpaired bones 2 maxillae 2 palatine bones 2 zygomatic bones + their temporal processes 2 zygomatic processes of temporal bones 2 nasal bones 2 lacrimal bones 2 inferior conchae 2 pterygoid plates of the sphenoid bone The ethmoid bone + it’s attached conchae The vomer

Physical characteristics Bones are rarely fractured in isolation Comparatively fragile, and articulate in a complex

fashion Maxilla makes up the greatest portion Fractures are usually comminuted These complex bones are so designed to withstand

forces of mastication from below They are easily fractured by relatively small impact

from other directions The nasal bones are least resistant, followed by the

zygomatic arch, to forces from the front and the side, while the maxilla is sensitive to horizontal impact

The majority of the skeleton of the middle third of the face is composed of wafer thin sheets of the cortical bone with stronger bony reinforcement comprising: The palate and alveolar process The lateral rim of the piriform aperture

extending up via the canine fossa to the medial orbital rim and then to the glabella

Zygomatic buttress and the connections to the inferior and lateral orbital margins and the zygomatic arch

The orbital rims The pterygoid plates

Anterior or canine pillars Starts in the region of the alveolar process of the

canine, forms the lateral boundary of the anterior nasal aperture and continues as the frontal process of the maxilla to the frontal bone

Middle or zygomatic pillars Starts in the region of the first molar, bends uo

and out as the zygomaticoalveolar crest and zygomatic process of the maxilla, and continues up to end at the zygomatic process of the frontal bone

Posterior or pterygoid pillars Pterygoid process of sphenoid bone

Supraorbital rims with frontal bone Infraorbital rims Alveolar process

Nervous supply – CN V2 – infraorbital, palatine branches,

nasopalatine nerves Blood supply – third part of maxillary

artery

Typical causes include Direct violence

RTA, Battery, fist fights, falls, blows from objects, occupational hazards

Indirect violence Crush injuries

Automobile accidents Aeroplane crashes Mining accidents

Le Fort’s classification (1901) Le Fort I, II, III

Erich’s classification (1942) Horizontal, pyramidal, transverse

Classification based on relationship of fracture line to zygomatic bone Subzygomatic, suprazygomatic

Classification based on level of fracture line Low, mid, high level fractures

Rowe and Williams (1985) # not involving teeth and alveolus

Central region # of the nasal bone and/or the nasal septum # of the frontal process of the maxilla # of the above which extend into the ethmoid bone

(naso-ethmoid #s) # of the above which extend into the frontal bone

(fronto-orbito-nasal #s) Lateral region

#s involving the zygomatic bone, arch, and maxilla (zygomatic complex #s)

#s involving the teeth and alveolar bone Dento alveolar Subzygomatic

Le fort I Le fort II

Suprazygomatic Le fort III

Marciani’s classification (1993) Le fort I – low maxillary #s

Ia – low maxillary #s/multiple segments Le fort II – pyramidal #s

IIa - Pyramidal and nasal #s IIb – pyramidal and naso-orbito-ethmoidal complex

#s Le fort III – craniofacial dysjunction

IIIa – craniofacial dysjunction and nasal # IIIb – craniofacial dysjunction and NOE #

Le fort IV – le fort II or III with cranial base # IV a - +supraorbital rim # IVb - +anterior cranial fossa and supra orbital rim # Ivc - +anterior cranial fossa and orbital wall #

Rowe and Killey (1968) Type I – no significant displacement Type II - #s of the zygomatic arch Type III – rotation around the vertical axis

Inward displacement of the orbital rim Outward displacement of the orbital rim

Type IV – rotation around the longitudinal axis Medial displacement of the frontal process Lateral displacement of the frontal process

Type V – displacement of the complex en-bloc Medial Inferior Lateral (rare)

Type VI – displacement of the orbitiantral partition Inferiorly Superiorly (rare)

Type VII – displacement of the orbital rim segments Type VIII – complex comminuted #s

Rowe (1985) similar to that of Larsen and Thomsen (1968) Group A – stable #, showing minimal or no

displacement and requiring no intervention Group B – unstable #, with grat displacement

and disruption at the frontozygomatic suture and comminuted #s. Requires reduction and fixation

Group C – stable #, other types of zygomatic #s, which require reduction but no fixation

In 1961 Knight and North classified zygomatic fractures by the direction of displacement on a Waters’ view radiograph

#s of the zygomatic complex involving the orbit Minimal or no displacement Inward and downward displacement Inward and posterior displacement Outward displacement Comminution of the complex as a whole

#s of the arch not involving the orbit minimal or no displacement V- type in-fracture Comminuted #

In 1990, Manson and colleagues proposed a method of classification based on the pattern of segmentation and displacement.

Fractures that demonstrated little or no displacement were classified as low energy injuries. Incomplete fractures of one or more articulations may be present.

Middle-energy fractures demonstrated complete fracture of all articulations with mild to moderate displacement. Comminution may be present .

High-energy injuries were characterized by comminution in the lateral orbit and lateral displacement with segmentation of the zygomatic arch.

For ordinary practical purposes in discussing signs and symptoms and plannimg treatment, a simpler classification is adequate Dento alveolar #s Zygomatic complex #s Nasal complex #s Le fort I #s Le fort II #s Le fort III #s Extended Le fort #s

Zygomaticofrontal suture – lateral canthus of the eye

Zygomatucotemporal suture – lateral side of the face

Zygomaticomaxillary suture – infra orbital margin

Zygomaticosphenoid suture – not easily accessible

Split across Comminuted With/without displacement

As with all fractures, NOE fractures are classified as unilateral or bilateral, open or closed, and simple or comminuted. Three types of NOE fractures have been well described.

Type I fracture maintains the attachment of the MCT to a large single nasoethmoidal fracture segment; repairing this type of fracture is straightforward.

Type II fracture shows more comminution yet maintains the attachment of the medial canthus to a sizable bony segment.

Type III fractures display severe comminution with possible avulsion of the MCT from its bony attachment

Aka horizontal/guerin’s/ floating/ low level/ subzygomatic fracture

# line – commences at a point on the lateral margin of the nasal aperture, passes above the nasal floor, laterally above the canine fossa and traverses the lateral antral wall, dipping down below the zygomatic buttress and then inclines upward and posteriorly across the pterygomaxillary fissure to fracture the lower 1/3rd of the pterygoid laminae.

it also passes along the lateral wall of the nose and the lower 1/3rd of the nasal septum to join the lateral # behind the tuberosity

Typically bilateral, with fracture of lower third of nasal septum, but may be unilateral

May occur as a single entity or in association with Le Fort II & III #s

Usually caused by violent force applied over a more extensive area above the level of the teeth

May also be caused by a blow to the lower jaw

Slight swelling of lower part of face+upper lip Ecchymosis in labial and buccal vestibule,

contusion of skin of upper lip, laceration of upper lip and intra oral mucosa

Bilateral epistaxis or nasal bleeding Mobility of upper dentoalveolar portion of the

jaw Disturbed occlusion & difficulty in mastication Pain while speaking and moving jaw Cracked pot percussion note of maxillary teeth Fracture of the cusps of the cheek teeth Impaction of entire fragment, giving a classical

open bite

0° occipitomental (0° OM) 30° occipitomental (30° OM) True lateral skull (brow-up)

Closed reduction Place upper & lower arch bars and do IMF Internal fixation via internal suspension Circumzygomatic wiring or external

fixation For unilateral #s, do a closed reduction

and immobilization of the jaw

Aka pyramidal/ subzygomatic fractures # line runs below frontonasal suture from

the thin middle area of the nasal bones down on either side, crossing the frontal process of the maxillae into the medial wall of each orbit, and passing across lacrimal bones immediately behind the lacrimal sac. From this point, it passes downward, forward and laterally crossing the inferior orbital margin slightly medial or through the infraorbital foramen.

It then runs downwards and backwards across the lateral wall of the antrum below the ZM suture, and divides the pterygoid lamina at its middle third

Seperation of the block of the midface from the base of the skull is completed via the nasal septum and may involve the floor of the anterior cranial fossa

Usually caused by a violent force in an anterior direction sustained by the central region of the middle 1/3rd of the facial skeleton over an area extending from the glabella to the alveolar margin

Force may be delivered at the level of the nasal bones

Ballooning or moon face Bilateral circumorbital oedema and ecchymosis Bilateral subconjuctival hemorrhage confined to the

medial 1/3rd of the eye and enopthalmos Depressed nasal bridge Shortening of the face with anterior open bite Dish shaped face Bilateral epistaxis Masticatory and speech difficulty Loss of occlusion Airway obstruction Surgical emphysema CSF leak Step deformity of infraorbital margins Anaesthesia &/or paresthesia of the cheek

0° occipitomental (0° OM) 30° occipitomental (30° OM) True lateral skull (brow-up)

Aka transverse / suprazygomatic/high level fracture

# line runs from near the Fn suture transversely backwards, parallel with the base of the skull and involves the full depth of the ethmoid bone, including the cribriform plate. Within the orbit, the # line passes below the optic foramen into the posterior limit of the inferior orbital fissure.

From here, it extends in 2 directions: Posteriorly across the PM fissure to # the root of the

pterygoid laminae Anteriorly across the lateral wall of the orbit seperating

the zygomatic bone from the frontal bone

Usually caused by trauma inflicted over a wide area at the orbital level

Force is usually applied from a lateral direction with severe impact

Initial impact is taken by the zygomatic bone, resulting in depressed fracture

Because of the severe impact, the entire middle face thus hinges about the fragile ethmoid bone and the impact will be transmitted on the contralateral side resulting in laterally displaced zygomatic # of the opposite side (craniofacial dysjunction)

Mobility of the entire middle facial skeleton as a block can be felt on gentle manipulation

Panda facies within 24 hours Racoon eyes Bilateral subconjuctival oedema without posterior limit Tenderness and separation at FZ sutures causing lengthening of

the face and lowering of the ocular level Unilateral or bilateral hooding of the eyes Dish face deformity Enopthalmos, diplopia od impairment of vision, blindness Epistaxis, CSF rhnorrhoea Flattening, widening and deviation of the nasal bridge Posterior gagging, anterior open bite Lateral displacement of midline in upper jaw Gagging of occlusion of molars at one side and posterior open

bite at the other side due to lateral displacement of #

0° occipitomental (0° OM) 30° occipitomental (30° OM) True lateral skull (brow-up) Coronal section tomography CT +/- 3-D reconstruction