Imaging of Facial Trauma

www.RiTradiology.com


Imaging of Facial Trauma
Rathachai Kaewlai, MD
Division of Emergency Radiology, Ramathibodi Hospital, Mahidol
University, Bangkok
Emergency Radiology Minicourse 2014
Updated May 2014



Before We Start…
•  Facial x-ray is overrated
•  CT is the current standard for most facial fracture imaging beyond
nasal bone
•  Still, we need to learn both XR and CT
•  Key for XR: Hazy sinuses, Lines of Dolan
•  Key for CT: urgent findings, significant soft tissue injuries, fracture
pattern recognition



Facial Bones
http://encyclopedia.lubopitko-bg.com/Axial_Skeleton.html



Facial Buttresses: 4 Vertical



Facial Buttresses: 5 Transverse
1 superior orbital rim
2 inferior orbital rim
3 maxillary alveolar rim
4 mandibular alveolar rim
5 inferior border of mandible



Facial Segments
Upper Face: frontal, superior orbit
(part of skull)
Lower Face : mandible
Mid Face: other orbit, nasal, zygoma,
Le Fort, maxillary sinus,
dentoalveolar, NOE, ZMC
11%
70%
19%
% indicate distribution of facial fractures
Ref: Mundinger et al. J Craniomaxillofac Surg 2014



About Facial Trauma
•  Mundinger J Craniomaxillofac Surg 2014 (n = 8127)
–  Male 77.6%
–  Right 28%, midline 36%, left 36%
–  One fracture pattern 52% (most common = nasal #)
–  Panfacial injury 1.1%
–  Bilateral fractures 18.9%
–  Association:
•  C-spine fracture 6.6%
•  Skull base fracture 7.6% (greatest in Le Fort II, III or any Le Fort
combinations)



Role of Imaging
•  Detection of soft tissue and bony injuries
•  Characterization of soft tissue and bony injuries
•  Surgical planning
•  CT preferred over x-ray
–  Much more accurate than x-ray
–  Easier to perform in multi-trauma, non-cooperative patients
–  If patients going to have CT for other indications
–  If you think of injury other than simple nasal fracture



Wisconsin Criteria
•  For obtaining facial CT in multi-trauma patient
•  Any 1 of 5 criteria
–  98% sensitive for presence of fracture
–  88% NPV for all fractures
–  Reduce CT use by 9%
•  Bony stepoff or instability
•  Periorbital swelling or contusion
•  GCS <14
•  Malocclusion
•  Tooth absenceSitzman et al. Plast Reconstr Surg 2011



Standard X-ray Projections
•  Facial trauma series
–  AP/PA
–  Caldwell’s
–  Water’s
–  Towne’s
–  Lateral
–  (+/- base)
a
5-6 views



Standard X-ray Projections
•  Mandible trauma series
–  AP
–  Lateral
–  Towne’s
–  Both obliques
5 views



Interpreting Facial X-rays
•  Hazy PNS
•  Lines of Dolan
–  AKA: Elephant head (Lee Rogers)
–  Water’s view
Water view is the cornerstone



Don’t Rely on X-rays Too Much,
Use CT Liberally
Unilateral NOE fracture ZMC fracture



CT Techniques:
Facial CT Extended Brain CT
•  Smaller FOV
•  Frontal sinus to mandible
•  Nose to mandibular condyles
•  Thinner collimation
–  1 mm bone
–  2 mm soft tissue
•  2D (coronal and sagittal) reformats,
and 3D shaded surface display --
routine



Imaging Approach: CT
Specifically search for urgent findings
Fracture No fracture
Nasal
Zygomatic arch
Mandible
Dento-alveolar
Le Fort I, II, III
ZMC, frontal
Maxillary
Orbit
NOE
Airway
Vision
NoYes
Clear paranasal sinus?
Pterygoid plates?



Airway Compromise:
Nasal Septal Hematoma
•  Usually clinically apparent
•  Must be identified quickly
–  Epistaxis can be life threatening
–  May lead to compromised nasal
airway
–  Late complications: infection,
abscess, necrosis -> saddle nose
deformity



Airway Compromise:
Flail Mandible
•  Fractures of symphysis + bilateral
condyles, rami or angles
•  Airway may be occluded 2/2
–  Large pharyngeal hematoma
–  Inability to maintain tongue in anterior
position in supine patient



Vision Compromise:
Globe Rupture
•  Full-thickness scleral or
corneal wound
•  Common at anterior surface of
eye but can be clinically occult
in posterior
•  CT to assist in diagnosis*
–  Sensitivity 60-75%
–  Specificity 76-100%
•  CT to identify foreign bodies
and concomitant injuries
*Romaniuk Emerg Med Clin N Am 2013 Intraocular air and foreign body
Extruded vitreous and intraocular air



Vision Compromise:
Globe Rupture
•  Change of globe contour with
loss of volume “Flat-tire” sign
•  Scleral discontinuity
•  Intraocular air
•  Intraocular foreign body
•  Indirect signs: lens
displacement into vitreous
Narrow anterior chamber
Contour abnormality “Flat-tire” sign.
Green arrows = trapped extraocular air



Vision Compromise:
Orbital Apex Fracture
•  Optic canal can be fractured
causing traumatic optic
neuropathy and vision loss
•  True emergency if there is
radiological and clinical evidence
of optic nerve impingement
Image from medscape.com
Orbital apex fracture



Vision Compromise:
Lens Injuries
•  Tear of zonular fibers that hold
lens to ciliary muscles
•  Luxation
•  Dislocation
•  Traumatic cataract
•  If bilateral, think collagen
vascular disease or
homocysteinuria
Diagram: getsomenbeo.wordpress.com Rt: Lens subluxation. Lt: Lens dislocation



Vision Compromise:
Ocular Detachments
•  Laceration of 3 layers of globe
leading to fluid collections
•  Retinal detachment
–  Retinal separated from choroid
–  Vitreous in subretinal space
–  Possibility of non-accidental
trauma in children
–  V-form with apex at optic disk and
anterior part at ora serrata
•  Choroidal detachment
–  Collection in suprachoroidal space
between choroid and sclera
–  Biconvex lens shape
Choroidal detachment
Retinal detachment



Vision Compromise:
Retrobulbar Hemorrhage
•  Increased IOP transmits to optic
nerve and globe  compression
of retinal vessels  retinal
ischemia  loss of vision in
60-100 min
•  “Orbital compartment syndrome”
•  Arterial bleeding from infraorbital
or ethmoidal arteries
•  Severe proptosis, tented
posterior sclera and stretched
optic nerve
•  Discrete hematoma rarely seen
•  Common associated orbital/
facial/cranial injuries
Retrobulbar hemorrhage with medial orbital wall fracture



Nasal Fracture
•  Most common site of facial #
•  Frontal blow, lateral blow, blow from below
•  Clinical diagnosis
–  X-ray misses up to half
–  When isolated, XR may be adequate
–  X-ray views: laterals and Water
•  CT when concern more than mere nasal
fracture



Nasal Fracture
•  What are features of #?
–  Unilateral or bilateral
–  Simple vs. comminuted
•  If comminuted, is there telescoping
or depression?
•  Is nasal septum involved?
–  Fracture or hematoma or both
•  What other fractures does the
patient have?
–  Frontal process of maxilla
–  ZMC
–  NOE
Patel et al. Semin Ultrasound CT MRI 2012
Bilateral nasal bone fractures with comminution and
depression on the right side. No telescoping or
septal involvement



Zygomatic Arch Fracture
•  Three fracture lines: one at each
end and third in the center
•  Limited motion of mandible
(trismus) by
–  Impinged coronoid process
–  Masseter origins



Mandible Fracture
•  Typical bilateral injury pattern
–  Force transmitting on U-shaped mandible,
producing bilateral #
–  Must always search for 2nd fracture
–  42% unifocal*
•  7 anatomic regions
–  Symphysis/parasymphysis
–  Alveolar process
–  Body
–  Angle
–  Ramus
–  Coronoid
–  Condyle: head, neck, subcondyle
*Murray et al. Emerg Med Clin N Am 2013
http://dermatologic.com.ar/7.htm



Mandible Fracture
•  Forced occlusion: TMJ or condylar area
•  Blow from lateral or frontolateral: body or angle #
•  # often displaced because of traction of attached muscles
Gray’s Anatomy



Mandible Fracture
•  X-ray
–  PA view: rami, body
–  Towne view: condyles, rami, TMJ
–  Lateral & oblique views: body, angle
•  Panoramic x-ray
–  Rami and condyles
–  Tooth
–  Not always available in emergency
setting



Mandible Fracture
•  CT is the imaging modality of choice
•  Suggested approach:
–  Cooperative patient  screening XR + panoramic UNLESS 1)
suspected other injuries, 2) will get CT for other indications
–  Un-cooperative patient  CT



Dentoalveolar Fracture
•  Universal Numbering System (American Dental Association: ADA)
for secondary teeth 1-32
•  Crown (above gingiva) + root (in alveolar bone)
•  Tooth injuries
–  Luxation
•  Complete (avulsion) vs. partial
–  Subluxation
–  Fracture
http://www.simplestepsdental.com/i/D/DNTKnowUnivNumSys.gif



Dentoalveolar Fracture
•  Any portion of alveolar process
•  Maligned and displaced teeth
•  Further imaging:
–  Tooth x-ray (?fracture)
–  CXR (?aspirated teeth)
Maxillary dentoalveolar process fracture



Nasal
Zygomatic arch
Mandible
Le Fort I, II, III
ZMC, frontal
Maxillary
Orbit
NOE
Airway
Vision
NoYes
Pterygoid plates?



Pterygoid Plate Fracture
•  90-100% Le Fort #
•  Isolated pterygoid plate
fracture very rare
•  Absence of pterygoid plate #
rules out Le Fort



Le Fort Fractures
•  Among the most severe facial fractures
•  Progressively severe category from I  III
•  Separation (partial or complete) of maxilla from remainder face
•  All extend through posterior face transecting pterygoid plates
•  I, II, III and combined
Hopper RA, et al. Radiographics 2006



Le Fort I Fracture
•  Transverse fracture of inferior
maxillae (involving all walls of
maxillary sinus except superior
walls), nasal septum and
pterygoid plates
•  Free-floating hard palate



Le Fort I Fracture
Diagram from Hopper RA, et al. Radiographics 2006



Le Fort II Fracture
•  Pyramid-shaped
•  Fractures of
–  Maxillary sinuses anterolateral
wall
–  Inferior orbital rim
–  Orbital floor
–  Nasofrontal suture
•  Free-floating midface



Le Fort II Fracture



Le Fort III Fracture
•  Most severe of all Le Fort
•  Separation of facial bones from
skull “craniofacial separation”
–  Zygoma separates from
sphenoid
–  Nasal bones and medial orbits
separated from frontal bone
Combined Le Fort II and III



Le Fort III Fracture
(with I & II)



Nasal
Zygomatic arch
Mandible
Le Fort I, II, III
Frontal
NOE
Orbit
ZMC
Maxillary
Airway
Vision
NoYes
Pterygoid plates?



Hazy Sinus + Intact Pterygoid Plates:
DDx
•  Frontal sinus fractures
•  Naso-orbital-ethmoidal (NOE) fractures
•  Orbital fractures
•  Zygomaticomaxillary complex (ZMC) fractures
•  Maxillary sinus fractures



Frontal Sinus Fracture
•  Anterior table
–  Thicker, require strong force to break
–  Cosmetic
•  Posterior table
–  Dural tear – CSF leak
–  Brain injury
•  Floor: superior orbital rim & medial
orbital roof
–  Nasofrontal duct or frontal recess
‪www2.aofoundation.org
NFD or frontal recess (dotted lines), a = Agger nasi
http://www.asnr.org/neurographics/Smith/2.shtml



Frontal Sinus Fracture
•  Strong suspicion for NFD injury if:
–  # fragments in nasofrontal outflow tract
–  Frontal sinus floor #
–  # medial wall of anterior table
•  Checklist
–  Which tables are involved?
–  Is there significant displacement or
comminution of either table?
–  Are there signs of NFD occlusion?
–  Are there associated intracranial
abnormality to suggest dural violation?



Naso-orbital-ethmoidal
(NOE) Fracture
•  Fracture disrupting: Medial orbit + nose +
ethmoid sinuses
Hazy maxillary and ethmoid sinuses



Naso-orbital-ethmoidal
(NOE) Fracture
•  Medial canthal tendon slings globe to
medial orbital wall
•  In NOE fracture, the tendon pulls fragment
laterally causing telecanthus
•  Simple vs. comminuted
•  Disrupted vs. non-disrupted medial canthal
tendon
Medial canthal tendon
Gray’s Anatomy



Orbital Fracture
•  Can be isolated or with other facial fractures
(NOE, ZMC, Le Fort)
•  Blow out vs. blow in
–  Blow out: bone displaced away from orbit due
to sudden pressure changes in orbit
–  Blow in: bone displaced into orbit from direct
PNS injury
Rad.washington.edu
Blow in fracture
Blow out fracture



Orbital Fracture:
EOM Entrapment
Normal Hooked Entrapped
Shape of IOM Flat Oval Round
Location of IOM Not in defect Portion lies within
defect
Whole muscle beneath/
within defect
Clinical eye exam required
Easily missed entrapped inferior rectus in
children because fragment springs back
into place “trapdoor”



Orbital Fractures
•  X-ray false negative 7%-30%
•  Up to 30% have ocular injury



Orbital Fracture: Medial Wall
•  Entrapment of medial rectus
results in horizontal motility
restriction
•  Loss of normal posteromedial
bulge of orbit
•  Check for NOE # and nasofrontal
duct disruption



Orbital Fracture: Checklist
•  Is the fracture large (> 1 cm2 of floor)?
•  Are orbital contents displaced?
•  Are there signs of EOM entrapment?
•  Are there associated ocular injuries?
•  Are there associated intracranial injuries?



Zygomaticomaxillary Complex (ZMC)
Fracture
•  4 principle fracture lines:
–  Lateral orbital rim
–  Zygomatic arch
–  Zygomaticomaxillary buttress
Diagrams from Buchanan EP, et
al. Plast Reconstr Surg 2012



ZMC Fracture
•  4 principle fracture lines:
–  Lateral orbital rim
–  Zygomatic arch
–  Zygomaticomaxillary buttress



ZMC Fracture
•  2 of 4 are orbital structures
–  # orbital volume and contents can be
affected
–  Globe, nerve, EOM
–  Orbital apex
•  Can cause impaired mandible
motion esp. if depressed
•  Infraorbital nerve foramen
Decreased orbital volume
Compression of temporalis muscle



Maxillary Sagittal Fractures:
•  Types of maxillary sinus fractures:
Maxillary sagittal, palate, alveolar
process, Le Fort
•  Maxillary sagittal #: anterior wall only
(normal pterygoid, zygomatic arch)



Multiple Patterns
•  Nasal + NOE
•  Nasal + ZMC
•  Nasal + frontal process of
maxilla
•  ZMC + orbit
•  Le Fort + ZMC
•  Le Fort + NOE
•  etc...



Panfacial
Injuries
•  At least one fracture in
all of 3 facial thirds



Conclusion
•  Facial fracture concomitant with mandible fracture 6-10%; facial CT
must include mandible and vice versa
•  Two critical areas – airways and orbits
•  Sinus haziness important sign on x-ray
•  CT useful if suspected more than nasal fracture
•  Clear sinus?
•  Pterygoid fracture?
•  Pattern recognition
•  Try to fit all fractures into one pattern (if possible) in the conclusion
of the report



Disclaimer
•  The information provided in this presentation...
–  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 be used to establish a legal
standard of care

Imaging of Facial Trauma

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