Imaging of Facial Trauma

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Discussion about role of imaging, imaging interpretation and significance of imaging (focus on CT) for evaluation of facial trauma.

Discussion about role of imaging, imaging interpretation and significance of imaging (focus on CT) for evaluation of facial trauma.

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  • 1. www.RiTradiology.com 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
  • 2. www.RiTradiology.com www.RiTradiology.com 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
  • 3. www.RiTradiology.com www.RiTradiology.com Facial Bones http://encyclopedia.lubopitko-bg.com/Axial_Skeleton.html
  • 4. www.RiTradiology.com www.RiTradiology.com Facial Buttresses: 4 Vertical
  • 5. www.RiTradiology.com www.RiTradiology.com 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
  • 6. www.RiTradiology.com www.RiTradiology.com 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
  • 7. www.RiTradiology.com www.RiTradiology.com 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)
  • 8. www.RiTradiology.com www.RiTradiology.com 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
  • 9. www.RiTradiology.com www.RiTradiology.com 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
  • 10. www.RiTradiology.com www.RiTradiology.com Standard X-ray Projections •  Facial trauma series –  AP/PA –  Caldwell’s –  Water’s –  Towne’s –  Lateral –  (+/- base) a 5-6 views
  • 11. www.RiTradiology.com www.RiTradiology.com Standard X-ray Projections •  Mandible trauma series –  AP –  Lateral –  Towne’s –  Both obliques 5 views
  • 12. www.RiTradiology.com www.RiTradiology.com Interpreting Facial X-rays •  Hazy PNS •  Lines of Dolan –  AKA: Elephant head (Lee Rogers) –  Water’s view Water view is the cornerstone
  • 13. www.RiTradiology.com www.RiTradiology.com Don’t Rely on X-rays Too Much, Use CT Liberally Unilateral NOE fracture ZMC fracture
  • 14. www.RiTradiology.com www.RiTradiology.com 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
  • 15. www.RiTradiology.com www.RiTradiology.com 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?
  • 16. www.RiTradiology.com www.RiTradiology.com 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
  • 17. www.RiTradiology.com www.RiTradiology.com 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
  • 18. www.RiTradiology.com www.RiTradiology.com 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
  • 19. www.RiTradiology.com www.RiTradiology.com 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
  • 20. www.RiTradiology.com www.RiTradiology.com 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
  • 21. www.RiTradiology.com www.RiTradiology.com 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
  • 22. www.RiTradiology.com www.RiTradiology.com 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
  • 23. www.RiTradiology.com www.RiTradiology.com 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
  • 24. www.RiTradiology.com www.RiTradiology.com 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
  • 25. www.RiTradiology.com www.RiTradiology.com 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
  • 26. www.RiTradiology.com www.RiTradiology.com 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
  • 27. www.RiTradiology.com www.RiTradiology.com 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
  • 28. www.RiTradiology.com www.RiTradiology.com 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
  • 29. www.RiTradiology.com www.RiTradiology.com 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
  • 30. www.RiTradiology.com www.RiTradiology.com 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
  • 31. www.RiTradiology.com www.RiTradiology.com 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
  • 32. www.RiTradiology.com www.RiTradiology.com Dentoalveolar Fracture •  Any portion of alveolar process •  Maligned and displaced teeth •  Further imaging: –  Tooth x-ray (?fracture) –  CXR (?aspirated teeth) Maxillary dentoalveolar process fracture
  • 33. www.RiTradiology.com www.RiTradiology.com Imaging Approach: CT Specifically search for urgent findings Fracture No fracture Nasal Zygomatic arch Mandible Le Fort I, II, III ZMC, frontal Maxillary Orbit NOE Airway Vision NoYes Clear paranasal sinus? Pterygoid plates?
  • 34. www.RiTradiology.com www.RiTradiology.com Pterygoid Plate Fracture •  90-100% Le Fort # •  Isolated pterygoid plate fracture very rare •  Absence of pterygoid plate # rules out Le Fort
  • 35. www.RiTradiology.com www.RiTradiology.com 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
  • 36. www.RiTradiology.com www.RiTradiology.com 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
  • 37. www.RiTradiology.com www.RiTradiology.com Le Fort I Fracture Diagram from Hopper RA, et al. Radiographics 2006
  • 38. www.RiTradiology.com www.RiTradiology.com Le Fort II Fracture •  Pyramid-shaped •  Fractures of –  Maxillary sinuses anterolateral wall –  Inferior orbital rim –  Orbital floor –  Nasofrontal suture •  Free-floating midface
  • 39. www.RiTradiology.com www.RiTradiology.com Le Fort II Fracture Diagram from Hopper RA, et al. Radiographics 2006
  • 40. www.RiTradiology.com www.RiTradiology.com 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
  • 41. www.RiTradiology.com www.RiTradiology.com Le Fort III Fracture (with I & II) Diagram from Hopper RA, et al. Radiographics 2006
  • 42. www.RiTradiology.com www.RiTradiology.com Imaging Approach: CT Specifically search for urgent findings Fracture No fracture Nasal Zygomatic arch Mandible Le Fort I, II, III Frontal NOE Orbit ZMC Maxillary Airway Vision NoYes Clear paranasal sinus? Pterygoid plates?
  • 43. www.RiTradiology.com www.RiTradiology.com Hazy Sinus + Intact Pterygoid Plates: DDx •  Frontal sinus fractures •  Naso-orbital-ethmoidal (NOE) fractures •  Orbital fractures •  Zygomaticomaxillary complex (ZMC) fractures •  Maxillary sinus fractures
  • 44. www.RiTradiology.com www.RiTradiology.com 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
  • 45. www.RiTradiology.com www.RiTradiology.com 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?
  • 46. www.RiTradiology.com www.RiTradiology.com Naso-orbital-ethmoidal (NOE) Fracture •  Fracture disrupting: Medial orbit + nose + ethmoid sinuses Hazy maxillary and ethmoid sinuses
  • 47. www.RiTradiology.com www.RiTradiology.com 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
  • 48. www.RiTradiology.com www.RiTradiology.com 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
  • 49. www.RiTradiology.com www.RiTradiology.com 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”
  • 50. www.RiTradiology.com www.RiTradiology.com Orbital Fractures •  X-ray false negative 7%-30% •  Up to 30% have ocular injury
  • 51. www.RiTradiology.com www.RiTradiology.com 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
  • 52. www.RiTradiology.com www.RiTradiology.com 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?
  • 53. www.RiTradiology.com www.RiTradiology.com Zygomaticomaxillary Complex (ZMC) Fracture •  4 principle fracture lines: –  Lateral orbital rim –  Zygomatic arch –  Zygomaticomaxillary buttress –  Inferior orbital rim Diagrams from Buchanan EP, et al. Plast Reconstr Surg 2012
  • 54. www.RiTradiology.com www.RiTradiology.com ZMC Fracture •  4 principle fracture lines: –  Lateral orbital rim –  Inferior orbital rim –  Zygomatic arch –  Zygomaticomaxillary buttress
  • 55. www.RiTradiology.com www.RiTradiology.com 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
  • 56. www.RiTradiology.com www.RiTradiology.com Maxillary Sagittal Fractures: •  Types of maxillary sinus fractures: Maxillary sagittal, palate, alveolar process, Le Fort •  Maxillary sagittal #: anterior wall only (normal pterygoid, zygomatic arch)
  • 57. www.RiTradiology.com www.RiTradiology.com Multiple Patterns •  Nasal + NOE •  Nasal + ZMC •  Nasal + frontal process of maxilla •  ZMC + orbit •  Le Fort + ZMC •  Le Fort + NOE •  etc...
  • 58. www.RiTradiology.com www.RiTradiology.com Panfacial Injuries •  At least one fracture in all of 3 facial thirds
  • 59. www.RiTradiology.com www.RiTradiology.com 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
  • 60. www.RiTradiology.com www.RiTradiology.com 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