imaging of facial trauma part 3

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Emergency Radiology: Imaging of Facial Trauma Rathachai Kaewlai, MD

Imaging of Facial TraumaPart 2: Pathology (Cont’d)

Rathachai Kaewlai, MDSpecialized in Body Imaging and Emergency Radiology

[email protected] January 2007

The author is willing to receive any input, comments and corrections, Please do not hesitate to contact at the email address provided above.

mailto:[email protected]

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Outline

• Facial and mandibular fractures– Maxillary fractures

• Maxillary sagittal fracture• Alveolar process fracture• LeFort fractures

– Mandibular fractures• Imaging approach

– Plain film– CT

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Maxillary Fractures

• Types of maxillary fractures– Maxillary sagittal fracture (maxillary sinus fracture)– Palate fracture– Alveolar process fracture– LeFort fractures

• LeFort I fracture• LeFort II fracture• LeFort III fracture• Combination (bilateral, hemi)

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Maxillary Fractures

• Maxillary sagittal fracture– AKA maxillary sinus fracture– Fracture of a maxilla in sagittal plane, involving anteriorlateral wall

of a maxillary sinus (LeFort fractures represent bilateral maxillary fractures)

– Due to direct blow to either right or left midface– Plain film shows opacified maxillary sinus

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Maxillary Sagittal Fracture

68yearold man was found down.

There is a sagittal plane fracture of the left maxillary sinus (red arrow) with hemosinus (H)

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Maxillary Fractures

• Isolated alveolar process fracture– Fracture of any portion of the alveolar process– Clinically evident by malalignment and displacement of teeth

contained within fractured segment– Even on CT, fracture may be subtle and easily overlooked– Further imaging may be needed when the diagnosis is made

• Xray of the teeth or a panoramic view (look for dental injuries)• Chest radiograph (look for aspirated teeth)

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Maxillary Alveolar Process Fractures

Middle age women fell onto her mouth.Red arrows show the comminuted fractures of the maxillary alveolar process on the right side. These fractures are considered ‘open’ as they are connected to the oral cavity.

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LeFort Fractures

• Among the most severe fractures seen in face and associated with highenergy trauma

• Named after René LeFort, a French physician, who studied facial fractures in cadavers. Result was published in 1901

• Key facts– In each type, there is a partial or complete separation of maxilla

from the remainder of the facial skeleton– All LeFort fractures must extend through posterior face,

transects the pterygoid processes– Any combination of LeFort I, II, and III patterns can occur

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LeFort Fractures

• LeFort I fracture– Definition: transmaxillary fracture– Transverse (horizontal) fracture of inferior maxillae, involving

maxillary sinuses (all except superior walls), lateral margin of nasal fossa, nasal septum and pterygoid plates

– Clinical: free floating and movable hard palate with maxillary teeth– Imaging findings

• Opacified bilateral maxillary sinuses• Transverse fracture through the inferior maxillae above hard palate• Best shown and confirmed by coronal and sagittal reformatted CT

images

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LeFort I Fracture

48yearold man was kicked by a horse.LeFort I fracture line along bilateral maxillary sinuses (red arrows). Pterygoid plate fractures are present (not shown). Blue arrow indicates right mandibular fracture.H = Hemosinus

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LeFort Fractures

• LeFort II fracture– Pyramidshaped maxillary fracture, involving maxillary sinuses

(anteriorlateral walls), inferior orbital rim, orbital floor and nasofrontal suture

– Clinical: free floating, movable midface including maxillary teeth, hard palate and nose

– Imaging findings:• Opacified bilateral maxillary sinuses and orbital emphysema• Fractures of anterior/lateral walls of maxillary sinuses, inferior orbital

rims/floors and disruption of nasofrontal suture• Best seen and confirmed by coronal reformatted CT images

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LeFort II Fracture

Middle age man in motor vehicle collision.Fracture lines are demonstrated in red arrows. Fracture of pterygoid plates are present in all type of LeFort fractures, they are best seen in coronal images.

H = Hemosinus

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LeFort Fractures

• LeFort III fracture– AKA craniofacial disjunction– This fracture separates calvaria (skull) from the facial bones– Most severe LeFort fracture– Definition: separation of facial bones from the skull

• Zygomas separated from sphenoid at zygomaticosphenoid sutures• Nasal bones and medial orbital walls separted from frontal bone at

nasofrontal sutures• Best seen in coronal images

– Clinical: movement of face relative to the skull– Imaging findings:

• Plain film will underestimate degree of injury due to severe soft tissue swelling obscuring the bony details. CT is recommended

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Combined LeFort II and III Fractures

32yearold man, unrestrained driver in a motor vehicle accident.

Blue arrows define LeFort II fracture. Red arrows define the LeFort III fracture. Bilateral pterygoid plate fractures are present (not shown).

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Mandibular Fractures

• Etiology– Motor vehicle collisions + assaults: > 80% of mandible fractures

• Incidence– Ratio of mandibular to facial fractures = 2:1– Coexistence of mandibular and facial fractures = 610%– Rare in children

• If occurs, condyle is the most common location • Condyle is the growth center of mandible. Trauma to this area can

retard growth and cause facial asymmetry

• Clinical– Laceration under chin (common)– Pain, malocclusion, deviation of mandible on opening mouth

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• Classification – Mandible is divided into region for purpose of describing location of

fractures• Symphysis (= within the boundaries of central incisors)• Parasymphysis (within the boundaries of vertical lines distal to canine

teeth)• Body (include the region of third molar)• Angle (distal to the third molar)• Ramus• Condylar process (has separate classification system)• Coronoid process• Alveolar process (region normally contains teeth)

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• Relevant anatomy– Mandible is a ring or arc bone which is usually difficult to break in

one location. Approximately half of mandible fracture occurs in multiple locations.

• Search for a second fracture after initial fracture has been identified (usually at contralateral side)

– In symphyseal, parasymphyseal fractures: Digastric, geniohyoid and genioglossus muscles pull the symphysis downward posteriorly

– In angle fracture: 3 muscles attaching to the ramus of mandible (masseter, temporalis and medial pterygoid) pull the proximal fragment upward and medially

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• Imaging recommendation– Plain film mandible series (PA, lateral, Towne’s and bilateral

obliques) show nearly all fractures BUT may be difficult to obtain in multitrauma patients

– Panoramic radiography (orthopantogram) • Need patient in upright position• Not optimal as a single radiograph to detect mandibular fracture• Better to look for subtle tooth fracture

– CT• Show all mandibular fractures AND other facial fractures (co

existence 610%), as well as position and alignment of fragments• Display associated soft tissue injuries• Easy to perform in multitrauma patient

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Mandibular Fractures: Missed by Mandibular Series

Full mandible series fail to recognize fracture/dislocation later shown in CT scan.

Red arrows = Mandibular condyles which are located ‘too anterior’ than usual

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Mandibular Fractures: Missed by Mandibular Series

Same patient as in previous page. CT shows left symphyseal/ parasymphyseal fracture extending to the tooth (green arrows), and bilateral mandibular condyle fractures (red arrows). The findings represent ‘Flail mandible’.Limitation of plain films in previous page is likely due to 1. Inadequate coverage (PA projection does not include the inferior part of mandible) 2. Suboptimal technique (Oblique views are not true oblique)

If plain film is too be used, make sure to have all projections, adequate coverage and optimal technique. If in doubt, CT is the solution

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43yearold man, fell from height, presented with malocclusionOrthopantogram demonstrates a fracture of the right ramus of mandible (red arrows). Subtle ‘second’ site of fracture is at the left body (green arrows) with missing tooth ADA #19 which is confirmed in CT scan (next page).

Search for second site of fracture is

warranted when one sees mandibular

fracture

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Right Sagittal


Same patient as in previous page. CT confirms the fractures of the right angle of mandible (red arrows) and left body (green arrows). Axial image shows extension of fracture into the root of the left mandibular tooth, indicating an open fracture

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Mandibular Fractures Missed by Orthopantogram

21yearold man was punched at his left face by the righthanded.Orthopantogram shows a nondisplaced fracture of the left angle of mandible (red arrows), extending to the root of unerupted ADA #18.

Where is the second site of fracture?

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Mandibular Fractures Missed by Orthopantogram

Same patient as previous page.CT Orthopantogram (postprocessing images from axial CT) shows an additional nondisplaced fracture of the left parasymphysis (blue arrows).

Plain orthopantogram should not be used as a single imaging to look for mandibular fractures. It is useful for tooth fracture, not for mandible.

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Mandibular Fractures with TMJ Dislocation

19yearold woman in a rollover motor vehicle collision.Axial CT image (A) shows ‘empty glenoid sign’ (red line) indicating right temporomandibular joint dislocation. Image B (inferior to A) revealed a fracture of the right mandibular condyle (red arrow) with anterior medial displacement of the condyle due to the pull of lateral pterygoid muscle. The left glenoid fossa is normal.

C = Left condyle of mandible

A B

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Mandibular Fractures with TMJ

Dislocation

Same patient as in previous page.

3D reconstruction image on right lateral view makes it easier to understand the fracture site, dislocation and orientation of the fragment.

Red arrows = fracture of the base of right condyle of mandible

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Mandibular Fractures with Tooth Fracture

Young man in a motor vehicle accident.Tooth fracture of ADA #29 is apparent (blue arrow) in this orthopantogram. However, fracture of the right body of mandible is very subtle (red arrow) and may be detected only retrospectively. This confirms that orthopantogram is not an appropriate imaging technique to rule out or characterize mandible fractures.

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Mandibular Fractures with Tooth Fracture

Same patient as in previous page.In this case, CT demonstrates comminuted fracture of the right body of mandible (red arrow) and tooth fracture (blue arrow). With tooth fracture, orthopantogram and dedicated tooth radiograph are an appropriate and optimal technique.

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Imaging Approach Plain Film

• Friendly line (anterolateral antral wall of maxillary sinus)– Both intact

• NO ZMC or LeFort fractures• Blowout fracture• Isolated fractures of lateral orbital wall, zygomatic arch

– One disrupted• ZMC fractures• Maxillary sagittal fracture (isolated sinus fracture)

– Both disrupted• LeFort fractures

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Imaging Approach CT

• Clear sinus sign (= all sinuses and mastoid are clear of fluid)– Nasal bone fractures– Isolated zygomatic arch fractures– Orbital roof/lateral wall fractures – Mandible fractures

• Hemosinuses– Pterygoid plate fracture present probable LeFort fracture

• With fracture of lateral margin of nasal fossa = LeFort I• With fracture of inferior orbital rim = LeFort II• With fracture of zygomatic arch = LeFort III

– Maxillary wall fractures– Orbital floors, NOE region fractures– ZMC fractures

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Checklist for Facial Radiograph/CT

Treat lifethreatening injury first (ABC of trauma) CT is more accurate, faster to do than plain film and can be

performed at the same time as trauma head CT Emergency in face injury

Airway compromise due to severe soft tissue swelling, fracture or obstructed foreign body

Life threatening hemorrhage can be from nasal injury Facial fractures that compromise vision

Orbital apex fracture may injure optic nerve, requiring urgent Rx Entrapment of intraocular muscle requires urgent Rx

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Checklist for Facial Radiograph/CT

Facial structures are quite symmetrical Do not stop searching when see one abnormality If suspect for more than simple nasal fracture, do CT Significant (but can be subtle) fractures

Fracture involves the optic foramen which can cause permanent visual loss if not treated promptly

Fracture of the posterior wall of frontal sinus requires neurosurgical evaluation and may require antibiotics prophylaxis

Fracture/dislocation of the TMJ usually missed on initial survey. It can cause significant disability if left untreated

Look for significant soft tissue injuries Globe rupture, hemorrhage

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• The information provided in this presentation…– Does not represent the official statements or views of the Thai

Association of Emergency Medicine. – Is intended to be used as educational purposes only. – Is designed to assist emergency practitioners in providing

appropriate radiologic care for patients. – Is flexible and not intended, nor should they be used to establish a

legal standard of care.

imaging of facial trauma part 3

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