Week 7 - Blow out fracture Flashcards
What are 3 common causes if orbital trauma?
• Fist
• Elbow common in rugby
• Hocky Ball
What is the Mechanism of fracture?
• Force of blow -> backward displacement of eyeball - intraorbital pressure increases
- fracture in the weakest point of orbital wall
What are the signs of blow out fracture?
• Clinical findings associated with orbital blowout fracture may include:
• enophthalmos: due to increased orbital volume
• diplopia: due to extraocular muscle entrapment
• orbital emphysema: especially when the fracture is into an adjacent paranasal sinus (see: black eyebrow sign)
• malar region numbness: due to injury to the infraorbital
nerve
• hypoglobus
Classification of orbital fractures?
• Blowout fractures can occur through one or more of the orbital walls:
- inferior (floor)
- medial wall (lamina papyracea)
- superior (roof)
- lateral wall
What is a medial blowout?
• Medial blowout fractures are the second most common type, occurring through the lamina papyracea. Orbital fat and the medial rectus muscle may prolapse into the ethmoid air cells.
What is a superior blowout fracture?
• Pure superior blowout fractures (without associated orbital rim fracture) are uncommon. They are usually seen in patients with pneumatisation of the orbital roof
• Fractures may only involve the sinus, the anterior cranial fossa (less common), or both sinus an anterior cranial fossa. Fractures communicating with the anterior cranial fossa are at risk for CSF leak and meningitis.
What is lateral blowout fracture?
• Pure lateral blowout fractures are rare, as the bone is thick and bounded by muscle. If fractures are present they are usually associated with orbital rim or other significant craniofacial injuries.
Why is a CT scan preferred?
• CT is the modality of choice for assessment of the facial skeleton.
• A full assessment does not require the administration of contrast.
• Ideally, the acquisition should be performed using the thinnest detector settings, enabling thin-slice reconstructions along three orthogonal planes with a bone algorithm.
• Additional soft tissue algorithm reconstructions using larger slice thickness and 3D volumetric reconstruction are useful for assessing associated soft tissue injury and gauging facial asymmetry, respectively.
What are some other signs for a blowout fracture?
• In addition to evaluating the location and extent of fracture(s), other features requiring assessment and reported include:
• presence of intraorbital (usually extraconal)
haemorrhage: may result in stretching or compression of the optic nerve
• globe injury / rupture
• extraocular muscle entrapment: suspected if there is an acute change in angle of the muscle
• prolapse of orbital fat
What are indications for surgery?
• significant enophthalmos
• significant diplopia
• muscle entrapment, especially with “trapdoor fracture” in children
• large area fractures
What are the timings for surgery?
• The timing of surgery is a subject of debate. Many surgeons elect for semi delayed or late repair. This allows for assessment for noticeable enophthalmos, diplopia, or extraocular muscle impairment once the swelling has subsided .
• This must be balanced against the risk of developing fibrosis and more permanent structural impairment with longer delayed management
• Typically wait 7-14 days for oedema to settle
What techniques are used for clinical examination?
• Ocular exam, cornea, retina
• Vision
• Cover tests
• Motility
• Fusion
• Colour vision
• Fields
