- CLASSIFICATIONS OF FACIAL FRACTURES -
- Standard fracture patterns are classically described by Le Fort. Le Fort’s work was based on low-speed impact and does not completely reflect the breadth of trauma that is encountered in modern medicine.
- The AOCMF Classification Group developed a hierarchical three-level CMF classification system with increasing level of complexity and details. They proposed a systematic lecture for each facial division and specifics codes for the report. The AO classification is not widely adopted for now, but it is a promising research tool for the future.
- Although Lefort system has not been completely abandoned this AOCMF classification and more recent approaches are based on facial subunits and functional recovery. The more accepted proposal is to divide facial region into vertical facial thirds. The upper third includes the frontal bone, the mid third (midface) includes the maxilla, zygomas, orbits, nose and naso‐orbital ethmoidal complex and the lower third includes the mandible.
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The main patterns of midface are: naso-orbito-ethmoid (NOE) fractures, zygomaticomaxillary complex (ZMC) fractures and Le Fort fractures, and the orbit as a single unit. Some authors assume that upper Le Fort level fractures are commonly permutations of NOE, ZMC, and orbital fractures that are addressed individually. The occlusion-bearing fragment represents an independently managed subunit consisting of the palate, alveolus, and maxillary dentition and is liberated from the upper midfacial subunits at the lowest Le Fort level. These fractures require appropriate repair; so, it is important to check for these injuries specifically.
- FACIAL FRACTURES AND PATTERNS WITH SURGICAL RELEVANCE: TIPS -
- CRITICAL LOCATIONS
- UPPER THIRD: FRONTAL BONE
- MIDFACE
- High-impact force applied anteriorly to the nose and transmitted posteriorly through the ethmoid bone.
- Pattern of fractures involving the nasal bones and septum, ethmoid sinuses, and medial orbital walls.
- Isolated NOE are less frequent. Associations: 60% zygomaticomaxillary complex fractures, 20% panfacial fractures.
- Frequent complications: exophthalmos due to a decrease in intraorbital volume, telecanthus due to medial canthal tendon injury, and cerebrospinal fluid (CSF) rhinorrhea due to fracture through the cribriform plate.
- The Markowitz and Manson classification system categorizes fractures of the NOE complex according to whether the medial canthal tendon is involved. The tendon itself is not visible at multidetector CT, the radiologist’s report of the degree of comminution and displacement of the medial orbital wall at the level of the lacrimal fossa may be helpful for surgical planning of medial canthal tendon repair.
- Other associated injuries: nasofrontal and nasolacrimal duct.
- Direct traumatic blow to the malar eminence
- Tetrapod or quadripod fracture: zygomaticofrontal, zygomaticosphenoid, zygomaticomaxillary, and zygomaticotemporal sutures.
- The zygomatic bone plays an important role in defining the height and width of the midface.
- Zingg classification divides them into three types oriented to surgical treatment.
- The main complications and issues to report: the extent of orbital involvement, rotation and malar retrusion, orbital apex implication, status of the sphenozygomatic suture (displacement, overriding or angulation).
- High-force impact on the midface structures. Variable degree of craniofacial dissociation spanning multiple facial buttresses.
- Le Fort described three common fracture patterns, each caused by a force of a different magnitude and all including a fracture through the pterygoid plates. Depending on the distribution of forces through the facial skeleton, multiple Le Fort fracture patterns may occur at the same time, and different combinations may occur on the two sides of the face.
- Each of the Le Fort fractures has one or more components that are easily recognizable and unique to each.
- Two main types of orbital fractures: those that form part of a larger fracture pattern (ZMC, NOE, or Le Fort) and isolated blowout fractures.
- Orbital “blowout” fracture, occurs when direct traumatic impact on the globe is transmitted to the orbital roof, floor, or medial wall, displacing it outward, away from the orbit, while the orbital rim itself remains intact.
- Surgical emergencies: muscle entrapment, compressed neural structures, intraorbital hemorrhage and globe injury.
- INFERIOR THIRD: MANDIBLE
- TEETH
- MAXILLOFACIAL CT: SYSTEMATIC LECTURE IN FACIAL TRAUMA -
- Compiling information of mechanism of injury and physical examination.
- Looking for critical locations - urgent lesions in severe trauma: orbit, mandible, nose.
- Indirect and direct signs*.
- Looking for patterns of facial fractures.
- Specific checklist for each location.
- Look to the teeth.
- Don´t forget skull base, cervical spine, and soft tissues.
*One of the pillars of proper interpretation of imaging modalities evaluating CMF fractures is the knowledge of indirect and direct radiographic fracture signs in the CMF area. Indirect fracture signs include soft tissue swelling, paranasal sinus opacifications or air/fluid levels, and localized air collections (soft tissue emphysema).
- REPORTING FACIAL TRAUMA. CHECKLIST -
Radiology reports should address facial injuries in clinical context with categorization by the need for surgical repair, rather than containing a “laundry list” of fractures. This requires a detailed knowledge of the anatomy and biomechanics of the maxillofacial skeleton. The standardization of the maxillofacial examination using a validated checklist could facilitate the diagnosis and communication with surgeons.