Learning Radiology xray montage

Blowout Fracture of the Orbit

General Considerations
  • Isolated fractures, most commonly of the orbital floor
  • The cause is sudden, direct, blunt trauma in the form of a blow to the orbit with increase in intraorbital pressure
  • The orbital rim is relatively strong so force is transmitted to the weakest parts of the orbit which “blow-out”
    • Orbital floor which is the superior boundary of the maxillary sinus, or
    • Medial wall (the thin lamina papyracea) which is the lateral boundary of the ethmoid sinus
  • The nasal bone is also frequently fractured
  • The cause is usually a large object such as baseball, fist, automobile accidents, tennis ball and kick
Clinical Findings
  • Pain and tenderness
  • Diplopia on upward gaze
    • Due to entrapment of the inferior rectus and sometimes the inferior oblique muscles
  • Enophthalmos
    • Usually following initial swelling and proptosis
  • Patient reports feeling of pressure in orbit when attempting to blow nose
  • Facial anesthesia due to entrapment of the infraorbital nerve
  • Epistaxis
Imaging Findings
  • CT of the facial bones is the imaging study of choice
  • Orbital emphysema
  • Fracture of the floor or medial wall of the orbit
    • Depression of the fracture fragment(s)
  • Soft-tissue mass extending into the maxillary sinus
  • Complete or partial opacification of the ipsilateral maxillary sinus from hemorrhage or edema
Treatment and complications
  • Requirement for, timing of and method used for reconstruction of orbital floor is controversial
  • Surgical repair, when performed, usually occurs after swelling has subsided
    • If the diplopia does not resolve spontaneously
    • Severe enophthalmos (>2mm)
    • Large fractures (50% or more of floor)
  • Consists usually of resection of periosteum and repair of hole using either bone graft, plate or synthetic material such as Teflon
  • Long-standing entrapment can lead to vision impairment and enophthalmos

Blowout fracture of the orbit . Reformatted coronal CT of the facial bones demonstrates a fracture of the floor of the left orbit (white arrow) associated with orbital emphysema (blue arrow). A portion of the inferior rectus muscle (solid red arrow) projects into the maxillary sinus below (see normal opposite side--broken red arrow). There is blood in the maxillary sinus (white arrow). .
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