Neurosurgery notes/Trauma/Primary head Injury/Fractures/Craniofacial fractures

Craniofacial fractures

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Fractures

Frontal sinus fractures

General information

  • Frontal sinus fractures account for 5–15% of facial fractures.
  • In the presence of a frontal sinus fracture, intracranial air (pneumocephalus) on CT, even without a clinically evident CSF leak, must be presumed to be due to dural laceration (although it could also be due to a basal skull fracture, below).

Associated with:

  • Some may be delayed (some even by months or years) and include:
    • Numbness of the forehead
      • Due to supratrochlear and/or supraorbital nerve involvement.
    • Brain abscess
    • CSF leak with risk of meningitis
    • Cyst or mucocele formation:
      • Injured frontal sinus mucosa has a higher predilection for mucocele formation than other sinuses.
      • Mucoceles
        • May also develop as a result of frontonasal duct obstruction due to fracture or chronic inflammation.
        • Are prone to infection (mucopyocele), which can erode bone and expose dura with risk of infection

Embryology

  • The frontal sinus begins to appear around age 2 yrs
  • Becomes radiographically visible by age 8 as it extends above the superior orbital rim.

Normal frontal sinus anatomy

  • The sinus is lined with respiratory epithelium, the mucous secretion of which drains through the frontonasal duct medially and inferiorly into the middle nasal meatus.

Management

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Non surgical

  • Indication
    • Linear fractures of the anterior wall of the frontal sinus are treated expectantly.

Surgical

Indications
  • Exploration of posterior wall fractures are controversial.
    • Some argue that a few mm of displacement, or that CSF fistula that resolves may not require exploration. Others vehemently disagree.
  • Post wall fracture with CSF leak
Technique
  • In the presence of a traumatic forehead laceration, the frontal sinus may be exposed through judicious incorporation of the laceration in a forehead incision.
  • Without such a laceration,
    • Approach through either
      • A bicoronal (souttar) skin incision or
      • A butterfly incision (through the lower part of the eyebrows, crossing the midline near the glabella) is used.
    • Examination and Repair
      • Extradural
        • Not normally done
          • The act of lifting the dura off the floor of the frontal fossa in the region of the ethmoid sinuses often creates lacerations.
        • Indicated: In the presence of pneumocephalus, if no obvious dural laceration is found, the dural undersurface of the frontal lobes should be checked for leaks.
      • Intradural
        • Graft
          • Fascia lata is most desirable
          • Periosteum is thinner but is often acceptable
        • Held in place with sutures and must extend all the way back to the ridge of the sphenoid wing (fibrin glue may be a helpful adjunct).
        • A periosteal flap is placed across the floor of the frontal fossa to help isolate the dura from the frontal sinus and to prevent CSF fistula.
Dealing with frontal sinus
  • ❌ Simple packing of the sinus (with bone wax, Gelfoam®, muscle, or fat) increases the possibility of infection or mucocele formation.
  • Cranialization
    • Post wall of the sinus is removed
  • Exenterated
    • Mucosa is stripped from sinus wall down to the nasofrontal duct, the mucosa is inverted over itself in the region of the duct and is packed down into the duct, and temporalis muscle plugs are then packed into the frontonasal ducts)
    • The bony wall of the sinus is drilled with a diamond burr to remove tiny remnants of mucosa found in the surface of bone that may proliferate and form a mucocele.
  • If there is any remnant of sinus, it may then be packed with abdominal fat that fills all corners of the cavity.
Post-op risks related to frontal sinus injury include:
  • Infection
  • Mucocele formation
  • CSF leak.

Le Fort fractures

  • Complex fractures through inherently weak “cleavage planes” resulting in an unstable segment (“floating face”).

Le Fort I:

  • Transverse AKA transmaxillary fracture.
  • Fracture line crosses pterygoid plate and maxilla just above the apices of the upper teeth.
  • May enter maxillary sinus(es)
  • Treatment: maxfax

Le Fort II:

  • Pyramidal.
  • Fracture extends upward across inferior orbital rim and orbital floor to medial orbital wall, then across nasofrontal suture. Often from downward blow to the nasal area

Le Fort III:

  • Craniofacial dislocation.
  • Involves zygomatic arches, zygomaticofrontal suture, nasofrontal suture, pterygoid plates, and orbital floors (separating maxilla from cranium).
  • Requires significant force, and is therefore often associated with other injuries, including brain injuries
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