Imaging Studies
Nasal bone fractures
Nasal bone fractures can be diagnosed clinically by history and physical examination. Plain nasal films consisting of a lateral view coning down on the nose and a Waters view can confirm the diagnosis but are of little practical use. If edema has resolved and no deformity is noted, x-rays are unnecessary. [31, 32]
If deformity persists after resolution of edema, films may be obtained at follow-up to help plan the repair. Omission of ED films is cost-effective, since most nasal fractures do not need to be reduced.
A study comparing ultrasonography with computed tomography in the diagnosis of nasal bone fractures concluded there was no significant difference in findings. [33]
Nasoethmoidal fracture
If nasal fracture is suspected and evidence suggests ethmoidal bone involvement, such as CSF rhinorrhea or widening of the nasal bridge with telecanthus, plain films are of little use.
Coronal CT scan of the facial bones is the best test to determine the extent of fracture. [32, 17, 18] A 3-D reconstruction may help the consultant should surgery be required.
Zygoma fracture
The best film for evaluating zygomatic arch is an underexposed submental view, also known as bucket handle view, because arches appear as bucket handles.
Fracture also can be seen on a Waters view, and in some cases on a Towne view, of a facial series.
In a study assessing the diagnostic reliability of low dose multidetector CT (MDCT) and cone beam CT (CBCT) for the diagnosis of zygomaticomaxillary complex fractures in a blinded and randomized study design, the dose reduction did not significantly affect the objective visualization of fractures. In addition the sensitivity and specificity remained consistent among the low dose scan protocols. [34]
Tripod fracture
If tripod fracture is suspected, plain films should include Waters, Caldwell, and underexposed submental views.
Waters view is best to evaluate the inferior orbital rim, maxillary extension of the zygoma, and the maxillary sinus.
Caldwell view evaluates the frontal process of the zygoma and the zygomaticofrontal suture.
Underexposed submental view evaluates the zygomatic arch.
Coronal CT scan of facial bones often is used to better evaluate these fractures, especially with use of 3-D reconstruction to improve visualization of the fracture for reduction. If tripod fracture is strongly suspected, obtaining a CT scan directly without plain films is probably most cost-effective. [17, 18]
Le Fort fractures
Coronal CT scan of facial bones has replaced plain films in evaluation of Le Fort fractures, especially with use of 3-D reconstruction. Since Le Fort fractures often are mixed from one side to the other, CT scan is superior to plain films and makes visualization of the fracture for repair much easier. If CT is not available, a facial series with lateral, Waters, and Caldwell views can be used to evaluate the fracture. Almost all Le Fort fractures cause blood to collect in the maxillary sinus. [31, 17, 18]
Imaging of Le Fort I fractures demonstrates a fracture extending horizontally across the inferior maxilla, sometimes including a fracture of the lateral sinus wall, extending into the palatine bones and pterygoid plates.
Imaging of Le Fort II fractures demonstrates disruption of the inferior orbital rim lateral to the infraorbital canal and a fracture of the medial orbital wall and nasal bone. The fracture extends posteriorly into the pterygoid plates.
Imaging of Le Fort III fractures demonstrates fractures at the zygomaticofrontal suture, zygoma, medial orbital wall, and nasal bone extending posteriorly through the orbit at the pterygomaxillary suture into the sphenopalatine fossa.
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The bony walls of the orbit.
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Le Fort fractures.
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Mandibular fractures.
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3D CT scan of right displaced zygomaticomaxillary complex fracture.
