Radiology for Maxillofacial Trauma

N Drage 1

Maxillofacial Trauma

Nicholas DrageUniversity Dental Hospital,

Cardiff

Cardiff and Vale NHS Trust

Ymddiriedolaeth GIG Caerdydd a’r Fro

Radiographs are required to:

• Confirm presence of a fracture• Assess degree of displacement of

fractures• Identify other fractures

Signs of fractures

• Direct signs• Indirect signs

Direct signs

• Separation sign (radiolucent line)• Look for approximation (joining) of fracture lines in the mandible• NB If radiolucent line passes beyond bone margin then that

particular bone is not fractured

• Widening of the periodontal ligament space

• Widening of sutures• fronto-zygomatic suture, fronto-nasal suture, naso-maxillary suture and

in children the internasal suture

Direct signs

• Overlap sign (radiopaque line)• Due to overlapping of fragments.• Margins may be sharp or diffuse

• Abnormal linear density• Fragment displaced/rotated so it is seen in an ‘end on’ position

Direct signs

• Disappearing fragment sign• When thin bone plates are rotated out of the tangent

• Abnormal curvature• Step deformity

• Bone• Occlusal plane

• Displaced Bone

Radiology for Maxillofacial Trauma

N Drage 2

Indirect signs

• Soft tissue swelling• Paranasal sinus opacification

• NB fluid levels in sphenoid sinus on a supine lateral view likely to indicate skull base fracture

• Air in the soft tissues• Soft tissue (must exclude laryngeal, tracheal and oesophageal

laceration).• Orbital

• Due to orbital floor or medial orbital floor fracture• Intracranial

• Changes in the occlusal plane• Le Fort I or dento alveolar fracture• Condylar neck fracture

• Dental Injury!

Common fracture sites -mandible

Radiology for Maxillofacial Trauma

N Drage 3

Radiology for Maxillofacial Trauma

N Drage 4

Radiology for Maxillofacial Trauma

N Drage 5

Fractures of the middle third of the skeleton

• Dento alveolar• Zygomatic complex• Le Fort I, II, III• Naso-ethmoidal complex• Fractures of the orbit

Radiographic Views

• 0° Occipitomental radiograph• 30° Occipitomental radiograph• Submentovertex View• (Lateral skull)

What do you look for?

• Symmetry• Sharpness

• Accentuated sharpness if fragments are rotated into tangent with the x-ray beam (‘bright sign’ ‘railroad track’ or ‘trap door sign’

• Loss of normal sharp outline if fragment rotated out of tangent

• Sinus• Soft Tissue

Search Patterns

• Campbell’s lines (McGrigor’s Lines)• Trapnell’s line (used to assess mandible)• Dolan’s lines

• Orbital line• Zygomatic Line• Maxillary line

Radiology for Maxillofacial Trauma

N Drage 6

Radiology for Maxillofacial Trauma

N Drage 7