The zygomaticomaxillary complex fracture, also known as a quadripod fracture, quadramalar fracture, and formerly referred to as a tripod fracture or trimalar fracture, has four components, three of which are directly related to connections between the zygoma and the face, and the fourth being the orbital floor. Its specific locations are the lateral orbital wall (at its superior junction with the zygomaticofrontal suture or its inferior junction with the zygomaticosphenoid suture at the sphenoid greater wing), separation of the maxilla and zygoma at the anterior maxilla (near the zygomaticomaxillary suture), the

zygomatic arch In anatomy, the zygomatic arch (colloquially known as the cheek bone), is a part of the skull formed by the zygomatic process of temporal bone, zygomatic process of the temporal bone (a bone extending forward from the side of the skull, over the ...

, and the orbital floor near the infraorbital canal.

Signs and symptoms

On physical exam, the fracture appears as a loss of cheek projection with increased width of the face. In most cases, there is loss of sensation in the cheek and upper lip due to infraorbital nerve injury. Facial bruising, periorbital ecchymosis, soft tissue gas, swelling,

trismus Trismus is a condition of restricted opening of the mouth. The term was initially used in the setting of tetanus. Trismus may be caused by spasm of the muscles of mastication or a variety of other causes. Temporary trismus occurs much more freque ...

, altered

mastication Chewing or mastication is the process by which food is comminution, crushed and ground by the teeth. It is the first step in the process of digestion, allowing a greater surface area for digestive enzymes to break down the foods. During the mast ...

diplopia Diplopia is the simultaneous perception of two images of a single object that may be displaced in relation to each other. Also called double vision, it is a loss of visual focus under regular conditions, and is often voluntary. However, when occ ...

, and

ophthalmoplegia Ophthalmoparesis refers to weakness (-paresis) or paralysis (-plegia) of one or more extraocular muscles which are responsible for eye movements. It is a physical finding in certain neurologic, ophthalmologic, and endocrine disease. Internal ...

are other indirect features of the injury. The zygomatic arch usually fractures at its weakest point, 1.5 cm behind the zygomaticotemporal suture.

Cause

The cause is usually a direct blow to the malar eminence of the cheek during assault. The paired

zygoma The term zygoma generally refers to the zygomatic bone, a bone of the human skull that is commonly referred to as the cheekbone or malar bone, but it may also refer to: * The zygomatic arch, a structure in the human skull formed primarily by parts ...

s each have two attachments to the cranium, and two attachments to the

maxilla In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...

, making up the orbital floors and lateral walls. These complexes are referred to as the zygomaticomaxillary complex. The upper and transverse maxillary bone has the zygomaticomaxillary and zygomaticotemporal sutures, while the lateral and vertical maxillary bone has the zygomaticomaxillary and frontozygomatic sutures. The formerly used 'tripod fracture' refers to these buttresses, but did not also incorporate the posterior relationship of the zygoma to the sphenoid bone at the zygomaticosphenoid suture. There is an association of ZMC fractures with naso-orbito-ethmoidal fractures (NOE) on the same side as the injury. Concomitant NOE fractures predict a higher incidence of post operative deformity.

Components

ZMC complex fractures involve the lateral vertical buttress of the ZMC complex (lateral maxillary sinus and lateral orbital wall) and the upper transverse buttress (inferior orbital rim and floor, also including the zygomatic arch). Three of its four components are directly related to connections between the zygoma and the face. Two of its components are connections between the orbit and mid-face at the orbital medial wall and floor. Unlike an orbital blow out fracture, however, the orbital rim can be involved. The posterior vertical buttress is usually spared, and is more commonly involved in Lefort fractures. Specifically, one of two positions at the lateral orbital wall can be involved, either above at its superior junction with the zygomaticofrontal suture or below at its inferior junction with the zygomaticosphenoid suture at the sphenoid greater wing. Separation of the maxilla and zygoma at the anterior maxilla is also seen near the zygomaticomaxillary suture. The zygomatic arch itself is also transcortically involved, and the orbital floor near the infraorbital canal is disrupted.

Treatment

Non-displaced or minimally displaced fractures may be treated conservatively. Open reduction and internal fixation is reserved for cases that are severely angulated or comminuted. The purpose of fixation is to restore the normal appearance of the face. Specific attention is given to the position of the malar eminence and reduction of orbital volume by realigning the zygoma and sphenoid. Failure to correct can result in rotational deformity and increase the volume of the orbit, causing the eye to sink inwards. Fractures with displacement require surgery consisting of fracture reduction with miniplates, microplates and screws. Gillie's approach is used for depressed zygomatic fractures. The prognosis of tripod fractures is generally good. In some cases there may be persistent post-surgical facial asymmetry, which can require further treatment.

References

External links

{{Fractures Oral and maxillofacial surgery Bone fractures