mid face fracture
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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
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