Background
In approximately 400 BC, Hippocrates provided the first description of a variety of facial injuries. Rene Le Fort used cadaver studies in 1900 to provide detailed descriptions of 3 basic types of facial fracture.
Endotracheal anesthesia and radiography developed during the First World War led to better understanding and treatment of facial fractures.[1] During the Second World War, a multidisciplinary approach to treatment of facial fractures continued to improve the outcomes of severely injured soldiers. The more recent introduction of CT reconstruction, along with new surgical techniques, has improved cosmetic results immensely.
Pathophysiology
Maxillofacial fractures result from blunt or penetrating trauma.[2, 3, 4, 5] Blunt injuries are far more common, including vehicular accidents, altercations, sports-related trauma, occupational injuries, and falls. Penetrating injuries include gunshot wounds, stabbings, and explosions.
Mass, density, and shape of the striking object, as well as speed of impact, directly affect type and severity of facial injury. The force required to fracture various facial bones may be classified as high impact (greater than 50 times force of gravity [g]) or low impact (less than 50 g).
- High impact
- Supraorbital rim: 200 g
- Symphysis mandible: 100 g
- Frontal-glabellar: 100 g
- Angle of mandible: 70 g
- Low impact
- Zygoma: 50 g
- Nasal bone: 30 g
Simple nasal fractures are the most common of all facial fractures. They must be distinguished from the more serious nasoethmoidal (NOE) fractures. NOE fractures extend into the nose through the ethmoid bones. Fractures through the ethmoid are prone to cerebrospinal fluid (CSF) leaks from dural tears.
Zygomatic arch fractures tend to occur in 2-3 places along the arch. Often 3 breaks occur, 1 at each end of the arch and a third in the middle, forming a V-shaped fracture; this often impinges on the temporalis muscle below, causing trismus.
Zygomaticomaxillary (tripod) fractures result from a direct blow to the cheek. Fracture occurs at articulations of the zygoma with the frontal bone maxillae and zygomatic arch and often extends through the orbital floor. Because the infraorbital nerve passes through the orbital floor, hypesthesia often occurs in its sensory distribution.
Alveolar fractures occur just above the level of the teeth through the alveolar portion of the maxilla. Usually a group of teeth is loose, and blood is noted at the gingival line.
Le Fort fractures
Le Fort or midface fractures are classified into 3 types and occasionally are mixed from one side of the face to the other.
- Le Fort I: Horizontal maxillary fracture separates the maxillary process (hard palate) from the rest of the maxilla. Fracture extends through the lower third of the septum and involves the maxillary sinus. This is below the level of the infraorbital nerve and thus does not cause hypesthesia.
- Le Fort II: Pyramidal fracture starts at the nasal bone, extends through the lacrimal bone, and courses downward through the zygomaticomaxillary suture. It courses posteriorly through the maxilla and below the zygoma into the upper pterygoid plates. The inner canthus of the nasal bridge is widened. Because the fracture extends through the zygoma, near the exit of the infraorbital nerve, hypesthesia often is present. Bilateral subcutaneous hematomas often are present.
- Le Fort III: Craniofacial dysjunction also starts at the nasal bridge. It extends posteriorly through the ethmoid bones and laterally through the orbits below the optic foramen, through the pterygomaxillary suture into the sphenopalatine fossa. This fracture separates facial bones from cranium, causing the face to appear long and flat (ie, dish face).
For more information, see Medscape's Trauma Resource Center.
Epidemiology
Frequency
United States
Approximately 3 million facial injuries occur annually, but most do not involve maxillofacial fractures.[1, 2, 3, 4, 5, 6, 7] One study placed the incidence of severe maxillofacial injury (fractures and lacerations) at 0.04-0.09% for motor vehicle collisions. Motor vehicle-related injuries are more common in rural areas, and altercation-related injuries are more frequent in inner cities.
Mortality/Morbidity
Incidence of other major injuries is as high as 50% in high-impact facial fractures, compared with 21% for low-impact fractures. Motor vehicle collision-related fractures are more likely to have associated injuries than violence-related fractures. The mortality rate is as high as 12% in high-impact fractures but is rarely due to maxillofacial injury. The incidence of associated cervical spine injuries has been reported in the 0.2-6% range.
Sex
Adult male-to-female ratio is 3:1. Suspect domestic violence or sexual assault in women as this may coexist in 30% of cases.
Age
Male predominance is reduced to 3:2 in children. Child abuse should be suspected, particularly in nonmotor vehicular injuries. The incidence of maxillofacial fractures has increased in older patients.[8]
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