Etiology: Maxillary fractures often result from high-energy blunt force injury to the facial skeleton. Typical mechanisms of trauma include motor vehicle accidents, altercations, and falls. The patterns of fracture propagation in midface trauma originates from the work of René Le Fort. In 1901. He concluded that predictable patterns of fractures follow certain types of injuries. Three predominant types were described.
LeFort I fractures (horizontal) may result from a force of injury directed low on the maxillary alveolar rim in a downward direction. The fracture extends from the nasal septum to the lateral pyriform rims, travels horizontally above the teeth apices, crosses below the zygomaticomaxillary junction, and traverses the pterygomaxillary junction to interrupt the pterygoid plates .
LeFort II fractures (pyramidal) may result from a blow to the lower or mid maxilla. Such a fracture has a pyramidal shape and extends from the nasal bridge at or below the nasofrontal suture through the frontal processes of the maxilla, inferolaterally through the
lacrimal bones and inferior orbital floor and rim through or near the inferior orbital foramen, and inferiorly through the anterior wall of the maxillary sinus; it then travels under the zygoma, across the pterygomaxillary fissure, and through the pterygoid plates .
LeFort III fractures (craniofacial dysjunctions), may follow impact to the nasal bridge or upper maxilla. These fractures start at the nasofrontal and frontomaxillary sutures and extend posteriorly along the medial wall of the orbit through the nasolacrimal groove and ethmoid bones.
The fracture continues along the floor of the orbit along the inferior orbital fissure and continues superolaterally through the lateral orbital wall, through the zygomaticofrontal junction and the zygomatic arch. Intranasally, a branch of the fracture extends through the base of the perpendicular plate of the ethmoid, through the vomer, and through the interface of the pterygoid plates to the base of the sphenoid .
In most instances, maxillary fractures are a combination of the various Le Fort types. In very high-energy blows, maxillary fractures may be associated with fractures to the mandible, cranium, or both (ie, panfacial).
Physical examination
Evaluation of the maxilla and facial bones should be undertaken only after the patient has been fully stabilized and life-threatening injuries have been addressed. In particular, airway considerations and intracranial injuries must take immediate priority.
In general, patients with facial fractures have obscuration of their bony architecture with soft tissue swelling, ecchymoses, gross blood, and hematoma. Focal areas of swelling or hematoma may overlie an isolated fracture.
Periorbital swelling may indicate Le Fort II or III fractures. A global posterior retrusion of the mid face creates a flattened appearance (dish-face or pan-face) of the face.
The face and cranium should be palpated to detect for;
1. bony irregularities,
2. step-offs,
3. crepitus, and
4. sensory disturbances.
Mobility of the mid face may be tested by grasping the anterior alveolar arch and pulling forward while stabilizing the patient with the other hand. With high-impact force, the maxilla may be comminuted or impacted, in which case the bony framework is displaced or crushed but immobile.
A thorough nasal and intraoral examination should be completed. The intraoral examination should assess;
1. 1. occlusion,
2. overall dentition,
3. stability of the alveolar ridge and
4. palate, and
5. soft tissue.
During examination of the eyes and orbit, search for;
1. 1. integrity of the orbital rims,
2. orbital floor,
3. vision,
4. extraocular motion,
5. position of the globe, and
6. intercanthal distance.
Visual changes may signify a disturbance of the optic canal, problems within the globe or retina, or other neurologic lesions. Disturbances of extraocular motion or enophthalmos may signify a blowout in the orbital floor. An increased intercanthal distance implies displacement of the frontomaxillary or lacrimal bones or avulsion of the medial canthal ligament.
Definitive surgery should not be undertaken until the patient has been stabilized regarding other life-threatening injuries. Although treatment of maxillary fractures is not considered vital for survival, unrepaired fractures can potentially lead to significant functional and cosmetic complications.
Imaging Studies:
1. Plain radiographs
a. Waters and submental-vertical views:Sinus films provide information regarding the zygomatic arches, lateral and anterior sinus walls, and orbital rims
b. Lateral skull films
c. Cervical spine films are important to exclude injury to the vertebral column.
2. CT scans: CT scan images are taken of all patients with possible facial fractures. CT imaging is superior to plain films in helping delineate multiple fractures, evaluate associated cartilaginous or soft tissue injury, and assess for the presence of impingement into the optic canal.
Medical therapy:
Stabilize the patient and treat serious insults to the airway, neurologic system, cervical spine, chest, and abdomen prior to definitive treatment of the maxillofacial bones. Address emergencies related to maxillofacial trauma prior to definitive treatment.
Surgical therapy:
Fixation of unstable fracture segments to stable structures is the objective of definitive surgical treatment of maxillary fractures.
Fractures of the Zygoma
The zygoma forms the lateral and inferior portion of the orbit. It articulates with
1. the sphenoid bone in the lateral orbit,
2. the frontal bone superiorly,
3. the maxilla medially and inferiorly and
4. the temporal bone through the arch .
The prominent position of the zygoma makes it susceptible to traumatic injury, and its prominence accounts for fracture frequency. With the exception of isolated fractures of the zygomatic arch, all zygomatic fractures include components in the lateral orbit and the orbital floor. These internal orbital injuries may be linear or more severe, with portions of the orbit displaced inward (blow in) or outward (blow out). The zygoma fracture may be displaced medially, which reduces orbital volume, or laterally and inferiorly, which expands orbital volume. Patients almost always demonstrate limited mandibular excursion.
The symptoms of zygoma fractures include;
1. a periorbital and subconjunctival hematoma
2. numbness in the infraorbital nerve distribution (upper lip, ipsilateral nose, and upper anterior teeth)
3. inferior displacement of the palpebral fissure
4. impinge on the coronoid process of the mandible
5. loss of prominence of malar eminence
6. inferior globe dystopia or enophthalmos, and
7. step or level discrepancies over fracture sites
The radiographic evaluation should consist of an axial and coronal CT scan. Plain films of the Caldwell, Water’s, and submental vertex variety will identify the fracture.
Treatment
Displaced zygomatic fractures require reduction and immobilization.
The Superior Orbital Fissure Syndrome
Fractures involving the superior orbital fissure produce a combination of cranial nerve palsies known as the superior orbital fissure syndrome. The syndrome consists of;
1. ptosis of the eyelid,
2. proptosis of the globe,
3. paralysis of cranial nerve III, IV, and VI, and
4. anesthesia in the distribution of the first division of the trigeminal nerve.
If blindness occurs in combination with the superior orbital fissure syndrome, the condition is termed the “orbital apex syndrome.”
The CT scan may demonstrate fractures around the superior orbital fissure and the optic nerve, but in some cases no bone injury is seen. If the fractures produce blindness, medical (steroids) or surgical decompression of the optic canal is considered.
Nasoethmoidal Orbital Fractures
Nasoethmoidal orbital fractures consist of injury to one or both frontal processes of the maxilla and the nose. The frontal process of the maxilla contains the attachment of the medial canthal ligament. If the medial orbital rim and its canthal attachment are dislocated, telecanthus results. They are frequently accompanied by damage to the dura and the anterior cranial structures. The diagnosis of a nasoethmoidal orbital fracture is suggested by the presence of;
1. nasal bleeding,
2. a depressed, comminuted nasal fracture with a shortened nose,
3. pain and tenderness over the frontal process of the maxilla,
4. medial canthal ligament bone crepitation, and
5. bilateral eyelid hematomas.
Fractures in the nasoethmoidal area are only properly visualized by axial and coronal computed tomograms.
Fractures of the internal orbit
Internal orbital fractures may involve;
1. medial wall,
2. floor,
3. lateral wall.
The most frequent internal orbital fracture is the “blow-out” fracture, which is usually confined to the medial portion of the floor and the lower portion of the medial orbital wall. Depressed fractures involving this portion of the orbit allow the orbital soft tissue to be displaced into the maxillary and ethmoid sinuses, effectively reducing orbital volume. Fractures of the internal orbit may be pure or associated with other orbital rim fractures. The infra-orbital nerve travels obliquely across the orbital floor from the middle third of the orbit anteriorly to the lateral portion of the orbit posteriorly, where it enters the inferior orbital fissure. These nerves are often damaged in orbital and zygomatic fractures, resulting in hypoesthesia, a clinical symptom that is universally present in floor fractures. Small fractures of the orbit floor may incarcerate orbital soft tissue contents. Frequently, the incarceration involves fat that is tethered to the extra-ocular muscles by virtue of fine ligaments running within the fat. Contusion damage to the extra ocular muscles represents the principle mechanism of double vision and is common.
Signs and Symptoms
1. palpebral and subconjunctival hematoma
2. diplopia and limited extraocular range
3. numbness in the inferior orbital nerve distribution
4. enophthalmos
The visual acuity should be examined and the possibility of a globe rupture, hyphema, retinal detachment, or similar globe injury excluded.
Radiographic Evaluation
The radiographic evaluation of orbital floor fractures involves CT scans with both axial and coronal views.
Mandibular fractures
The mandible represents the second most common facial bone injury. Mandibular fractures are often multiple; if a single mandible fracture is identified, the search for a second should be instituted. Mandibular fractures are classified according to;
1. dentition
a. dentulous,
b. partially dentulous,
c. edentulous
2. region of the mandible
a. condyle,
b. condylar neck,
c. ramus,
d. coronoid,
e. angle,
f. body,
g. symphysis.
3. open or closed
The diagnosis of mandible fractures is suggested by the presence of;
1. pain,
2. swelling,
3. tenderness
4. malocclusion.
5. numbness in the distribution of the mental nerve
6. Fractured, missing, or
dislocated teeth
7. Trismus
8. Condylar fractures or
dislocations frequently lacerate the ear canal.
The mandible has strong muscular attachments that influence its displacement following injury. Muscles that elevate the mandible include the masseter, the medial pterygoid, and the temporalis. The protrusor muscles are the lateral pterygoids. The depressor retractor group of muscles includes the geniohyoid and digastric muscles. The mylohyoid muscle may result in lingual rotation of the mandible. The direction of a fracture line may oppose fracture displacement by muscular forces.
The radiographic evaluation of the mandible consists of;
1. plain films,
2. CT scan, and
3. Panorex examination.
Treatment
1. intermaxillary fixation (arch bar)
2. plate and screw fixation
