Pediatric Orbital Blowout Fracture

Etiology: Trauma – classic history is hit in face by a batted ball
Imaging CT:
— Orbital fractures most common along medial wall and inferior wall
— Muscle entrapment can be suggested with herniation of fat through fracture and pointing of muscle towards fracture
Note: On maxillofacial trauma CT an air-fluid level in sinus is a clue that a fracture is present
Note: Always look at the globe for rupture in orbital trauma
DDX:
Complications:
— Orbital floor fractures are associated with entrapment of inferior rectus muscle if portion of muscle or its fascia extends and becomes trapped through fracture but entrapment is a clinical diagnosis that relies on clinical exam findings of a gaze palsy
— If there is fracture extension into a paranasal sinus the fracture is considered dirty
Treatment: Surgical if there is clinical or imaging evidence of entrapment
Clinical:
— Present with enopthalmous and diplopia
— Muscle entrapment usually a clinical diagnosis

Radiology Cases of Orbital Blowout Fracture

Radiology Cases of Left Orbital Blowout Fracture

CT of orbital blowout fracture — Coronal CT without contrast of the orbits in bone windows (above) shows a fracture line through the floor of the left orbit along with some intraorbital air medially. Coronal CT in soft tissue windows (below) shows herniation of fat through the orbital floor fracture and into the roof of the left maxillary sinus. The left inferior rectus muscle is coursing towards the fracture which suggests muscle entrapment.

CT of orbital blowout fracture — Coronal CT without contrast of the orbits (right) shows a discontinuity in the floor of the left orbit, with soft tissue herniated through the discontinuity into the left maxillary sinus.

CT of left orbital blowout fracture — Coronal CT without contrast of the orbits in soft tissue (above) and bone (below) windows shows a fracture defect in the floor of the left orbit with fat herniating through it into the left maxillary sinus.

Radiology Cases of Right Orbital Blowout Fracture

CT of subtle orbital blowout fracture — Coronal CT without contrast of the orbits obtained immediately after the injury in soft tissue (above left) and bone (above right) windows show a very small amount of soft tissue herniated into the roof of the right maxillary sinus. No fracture line was identified. Repeat coronal CT without contrast of the orbits obtained two days after the injury in soft tissue (below left) and bone (below right) windows now shows a large amount of soft tissue herniated into the roof of the right maxillary sinus.