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DOI: 10.1148/rg.263045710
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Diagnosis of Midface Fractures with CT: What the Surgeon Needs to Know1

Richard A. Hopper, MD, Shahram Salemy, MD and Raymond W. Sze, MD

1 From the Departments of Surgery (R.A.H., S.S.) and Radiology (R.W.S.), University of Washington, Seattle, Wash. Received May 3, 2004; revision requested August 18; final revision received July 22, 2005; accepted July 22. All authors have no financial relationships to disclose.

Figure 1
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  		Figure 1.  Drawing of the adult skull shows the four paired vertical buttresses and the four transverse buttresses, all of which exist in areas of relative increased bone thickness.

 

Figure 2
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  		Figure 2.  NOE fracture pattern. Axial nonenhanced CT image shows that the medial vertical maxillary buttresses (*) are posteriorly and laterally displaced due to disruption of the upper transverse maxillary buttress. The medial canthi of the lids are attached to the rims of the lacrimal fossae (black arrows). Widening of the transverse buttress has resulted in telecanthus. The telecanthus was treated with transethmoid wires placed behind the lacrimal fossae to rotate the segments inward and restore the intercanthal distance. The sagittal extension of the medial maxillary buttress along the medial orbital wall has also been disrupted, resulting in exophthalmos from the "blow-in" fractures (white arrow) and loss of nasal dorsal projection. Reduction and fixation of the frontal process of the maxilla to the frontal bone along with a bone graft to the medial orbital wall were used to treat the orbital relationship; however, a calvarial bone graft to the nasal dorsum was required to restore nasal projection.

 

Figure 3
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  		Figure 3.  Drawings show the Manson classification of NOE fractures. A type I fracture involves a large bone fragment. A type II fracture involves comminution of the bone fragments. A type III fracture is defined by avulsion of the medial canthal ligament from its osseous insertion.

 

Figure 4
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  		Figure 4.  NOE fractures. Coronal nonenhanced CT image shows a right-sided Manson type I fracture and a left-sided Manson type II fracture (among other fractures). In the type I fracture, note the large bone fragment (black arrow) with the attachment of the medial canthus. The fragment has been pulled laterally and inferiorly. This segment of the medial vertical maxillary buttress must be accurately reduced and fixated to reestablish intercanthal distance. In the type II fracture, the medial canthal attachment is on a small bone fragment, which is not visualized in this plane. The small bone fragment and tendon must be wired and plated to the defect in the medial vertical buttress (white arrow).

 

Figure 5
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  		Figure 5a.  Nasofrontal ducts. (a) Coronal nonenhanced CT image shows the normal anatomy in the region of the nasofrontal ducts (*). (b) Coronal nonenhanced CT image of a patient with NOE fractures shows comminution of the ethmoid region and likely disruption of the nasofrontal ducts (*). In this situation, the frontal sinus (FS) will be obliterated to prevent postoperative mucocele formation due to inadequate frontal sinus drainage.

 

Figure 5
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  		Figure 5b.  Nasofrontal ducts. (a) Coronal nonenhanced CT image shows the normal anatomy in the region of the nasofrontal ducts (*). (b) Coronal nonenhanced CT image of a patient with NOE fractures shows comminution of the ethmoid region and likely disruption of the nasofrontal ducts (*). In this situation, the frontal sinus (FS) will be obliterated to prevent postoperative mucocele formation due to inadequate frontal sinus drainage.

 

Figure 6
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  		Figure 6.  Drawing shows the quadripod nature of the zygoma. Note the four sutures, in particular the location of the zygomaticosphenoid suture at the lateral orbital wall.

 

Figure 7
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  		Figure 7.  ZMC fracture. Axial nonenhanced CT image shows a displaced fracture of the left zygoma. The rotational deformity of the zygoma is demonstrated by angulation of the lateral orbital wall at the zygomaticosphenoid suture. The lateral displacement (black arrow) of the lateral vertical buttress (*) has resulted in increased orbital volume and enophthalmos (white arrow).

 

Figure 8
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  		Figure 8.  ZMC fractures. Axial nonenhanced CT image shows comminuted fractures (black arrows) of the left upper transverse maxillary buttress, with increased facial width and impaction of the malar prominence (white arrows). These are common sequelae of the distracting forces of the masseter muscle. This comminuted and displaced fracture pattern requires a coronal scalp incision for proper exposure, reduction, and fixation of the buttress.

 

Figure 9
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  		Figure 9.  ZMC fractures. Axial nonenhanced CT image shows fractures at the zygomaticotemporal (bottom arrow) and zygomaticomaxillary (top arrow) sutures of the upper transverse maxillary buttress. The lateral vertical maxillary buttress (*) is displaced posteriorly and medially. The pull of the masseter muscle on the body of the zygoma has resulted in a rotational deformity with decreased malar projection. As long as the rotational deformity is corrected and the other maxillary buttresses are fixated by means of limited incisions, the zygomatic arch does not need to be exposed with a coronal scalp incision.

 

Figure 10
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  		Figure 10a.  Blow-out fractures of the orbital floor. (a) Coronal nonenhanced CT image shows a left orbital floor fracture without evidence of entrapment of the inferior rectus muscle (arrow). The inferior rectus remains flattened in cross-sectional appearance, indicating that the fascial support of the globe is likely intact. (b) Coronal nonenhanced CT image shows a left orbital floor fracture in another patient. The inferior rectus (arrow) is displaced inferiorly into the maxillary sinus. Note that the cross-sectional appearance of the muscle has changed from ovoid to circular. The fascial support has been disrupted, and the muscle is entrapped. (c) Coronal nonenhanced CT image shows a "trap-door" fracture of the left orbital floor in a pediatric patient. The orbital floor was disrupted by the impact but then sprang back into place, trapping the inferior rectus (arrow) within the maxillary sinus. Because the bone has returned to its anatomic location, the diagnosis could easily be missed unless attention is paid to the locations of the extraocular muscles. Trapdoor fractures require emergent treatment to optimize the chance of recovery.

 

Figure 10
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  		Figure 10b.  Blow-out fractures of the orbital floor. (a) Coronal nonenhanced CT image shows a left orbital floor fracture without evidence of entrapment of the inferior rectus muscle (arrow). The inferior rectus remains flattened in cross-sectional appearance, indicating that the fascial support of the globe is likely intact. (b) Coronal nonenhanced CT image shows a left orbital floor fracture in another patient. The inferior rectus (arrow) is displaced inferiorly into the maxillary sinus. Note that the cross-sectional appearance of the muscle has changed from ovoid to circular. The fascial support has been disrupted, and the muscle is entrapped. (c) Coronal nonenhanced CT image shows a "trap-door" fracture of the left orbital floor in a pediatric patient. The orbital floor was disrupted by the impact but then sprang back into place, trapping the inferior rectus (arrow) within the maxillary sinus. Because the bone has returned to its anatomic location, the diagnosis could easily be missed unless attention is paid to the locations of the extraocular muscles. Trapdoor fractures require emergent treatment to optimize the chance of recovery.

 

Figure 10
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  		Figure 10c.  Blow-out fractures of the orbital floor. (a) Coronal nonenhanced CT image shows a left orbital floor fracture without evidence of entrapment of the inferior rectus muscle (arrow). The inferior rectus remains flattened in cross-sectional appearance, indicating that the fascial support of the globe is likely intact. (b) Coronal nonenhanced CT image shows a left orbital floor fracture in another patient. The inferior rectus (arrow) is displaced inferiorly into the maxillary sinus. Note that the cross-sectional appearance of the muscle has changed from ovoid to circular. The fascial support has been disrupted, and the muscle is entrapped. (c) Coronal nonenhanced CT image shows a "trap-door" fracture of the left orbital floor in a pediatric patient. The orbital floor was disrupted by the impact but then sprang back into place, trapping the inferior rectus (arrow) within the maxillary sinus. Because the bone has returned to its anatomic location, the diagnosis could easily be missed unless attention is paid to the locations of the extraocular muscles. Trapdoor fractures require emergent treatment to optimize the chance of recovery.

 

Figure 11
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  		Figure 11a.  Fractures of the medial orbital wall with clinical evidence of entrapment of the medial rectus muscle. (a) Axial nonenhanced CT image shows the lamina papyracea impinging on the medial rectus (arrow). This result is evident from the angulation of the muscle in the orbit. (b) Axial nonenhanced CT image shows that the posteromedial bulge of the left lamina papyracea has collapsed toward the midline. This collapse has increased the orbital volume and resulted in enophthalmos, with retroposition of the ipsilateral globe (small arrow) relative to the coronal plane (white line). The affected medial rectus (large arrow) has lost the typical flattened profile seen in the uninjured contralateral orbit (*) and herniated into the fracture site.

 

Figure 11
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  		Figure 11b.  Fractures of the medial orbital wall with clinical evidence of entrapment of the medial rectus muscle. (a) Axial nonenhanced CT image shows the lamina papyracea impinging on the medial rectus (arrow). This result is evident from the angulation of the muscle in the orbit. (b) Axial nonenhanced CT image shows that the posteromedial bulge of the left lamina papyracea has collapsed toward the midline. This collapse has increased the orbital volume and resulted in enophthalmos, with retroposition of the ipsilateral globe (small arrow) relative to the coronal plane (white line). The affected medial rectus (large arrow) has lost the typical flattened profile seen in the uninjured contralateral orbit (*) and herniated into the fracture site.

 

Figure 12
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  		Figure 12a.  Orbital apex. (a) Axial nonenhanced CT image shows the normal anatomy of the orbital apices (*) with alignment of the zygoma and sphenoid along the lateral orbital wall (white line). (b) Axial nonenhanced CT image shows impingement of the orbital apex secondary to a sphenoid–skull base fracture. The orbital apex fracture was associated with loss of vision secondary to compression of the optic nerve by a fragment of the sphenoid (arrow) with inward angulation of the lateral orbital wall (white line). The fracture was emergently reduced, and the patient regained her vision.

 

Figure 12
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  		Figure 12b.  Orbital apex. (a) Axial nonenhanced CT image shows the normal anatomy of the orbital apices (*) with alignment of the zygoma and sphenoid along the lateral orbital wall (white line). (b) Axial nonenhanced CT image shows impingement of the orbital apex secondary to a sphenoid–skull base fracture. The orbital apex fracture was associated with loss of vision secondary to compression of the optic nerve by a fragment of the sphenoid (arrow) with inward angulation of the lateral orbital wall (white line). The fracture was emergently reduced, and the patient regained her vision.

 

Figure 13
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  		Figure 13.  Orbital roof fracture in an adult. Coronal nonenhanced CT image shows an isolated blow-in fracture of the left orbital roof (arrow). The associated exophthalmos and dural tears were treated with an intracranial approach.

 

Figure 14
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  		Figure 14a.  Patterns of pterygomaxillary disjunction. (a) Axial nonenhanced CT image shows a right-sided unilateral pterygomaxillary disjunction (white arrows), which has resulted in separation of the posterior vertical maxillary buttress (*) from the rest of the maxilla; this appearance is indicative of a Le Fort fracture. The contralateral pterygomaxillary junction is intact because the fracture exited in the form of a parasagittal palate fracture (black arrow). (b) Axial nonenhanced CT image shows comminuted bilateral pterygomaxillary disjunctions (white arrows) with a sagittal palate fracture (black arrow). There is a complete posterior maxillary fracture with disruption of both posterior vertical maxillary buttresses (*), resulting in separation of the maxilla from its attachment to the skull base.

 

Figure 14
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  		Figure 14b.  Patterns of pterygomaxillary disjunction. (a) Axial nonenhanced CT image shows a right-sided unilateral pterygomaxillary disjunction (white arrows), which has resulted in separation of the posterior vertical maxillary buttress (*) from the rest of the maxilla; this appearance is indicative of a Le Fort fracture. The contralateral pterygomaxillary junction is intact because the fracture exited in the form of a parasagittal palate fracture (black arrow). (b) Axial nonenhanced CT image shows comminuted bilateral pterygomaxillary disjunctions (white arrows) with a sagittal palate fracture (black arrow). There is a complete posterior maxillary fracture with disruption of both posterior vertical maxillary buttresses (*), resulting in separation of the maxilla from its attachment to the skull base.

 

Figure 15
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  		Figure 15.  Drawings show the common Le Fort fracture patterns. The Le Fort I pattern involves fractures through the inferior portions of the medial and lateral maxillary buttresses. The Le Fort II pattern involves fractures through the zygomaticomaxillary and frontomaxillary sutures. The Le Fort III pattern involves complete craniofacial dissociation.

 

Figure 16
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  		Figure 16.  Coronal nonenhanced CT image shows bilateral Le Fort I, II, and III fractures. The lateral and medial maxillary buttresses (white lines) are fractured inferiorly and superiorly (junctions of white lines and black lines). To confirm the diagnosis, pterygomaxillary disjunction and fractures of the zygomatic arches would need to be observed on axial images.

 

Figure 17
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  		Figure 17.  Coronal nonenhanced CT image shows right Le Fort I and bilateral Le Fort II fractures. The right medial maxillary buttress is fractured inferiorly (white arrow), producing a right Le Fort I pattern; it is also fractured superiorly (left black arrow), thus contributing to the bilateral Le Fort II pattern. The left-sided Le Fort II medial fracture (right black arrow) is not at the level of the nasofrontal junction; however, it is distinguished from the Le Fort I pattern in that a portion of the orbit is included in the mobile segment. The inferior portion of the left medial maxillary buttress is intact (*), thus making the Le Fort I pattern unilateral.

 




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