Blow out fracture Flashcards
Mechanical
Orbital Trauma:
methods
Fist
* Elbow common in rugby
* Hockey Ball
* Airbag inflation in RTA (Road Traffic Accident)
Mechanism of blowout fracture
Hydraulic mechanism: Retropulsion of the globe results in elevated intraorbital pressure, which transmits the force to the orbital walls creating a fracture
Buckling mechanism: Direct trauma to the infraorbital rim transmits the force posteriorly, creating a compression fracture of the orbital floor
Floor fractures first
Trapdoor = muscles can get stuck and blood supply cut off
Mechanical restriction, enormous overshoots, further forwards = limited elevation, limited depresson = on orbital floor
Orbital floor made up of maxilla + pallitine bone
Floor, medial wall + zygoma bone most likely to fracture
Make sure px don’t blow their nose because infection can spread up into orbit
signs of b.o.f
enophthalmos: due to increased orbital volume, eye sitting back, might be permenant
* 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
Subconjunctival Haemorrhage
Diplopia
Pain
Loss of Vision
* want to check everything, pupils e.c.t.
* loss of cheek sensation = infra orbital nerve affected
Classification:
of b.o.f.
Blowout fractures can occur through one or more of the orbital walls:
* inferior (floor)
* medial wall (lamina papyracea)
* superior (roof)
* lateral wall
Inferior blowout fracture:
* Inferior blowout fractures are the most common. Orbital fat prolapses into the maxillary sinus and may be joined by prolapse of the inferior rectus muscle. In children, the fracture may spring back into place (see trapdoor fracture). Most fractures occur in the floor posterior and medial to the infraorbital groove .
* In ~50% of cases, inferior blowout fractures are associated with fractures of the medial wall
Medial wall:
* 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.
Superior blowout fracture:
* Pure superior blowout fractures (without associated orbital rim fracture) are uncommon (very thick bone). 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 and anterior cranial fossa. Fractures communicating with the anterior cranial fossa are at risk for CSF leak and meningitis.
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.
what scan b.o.f.
- 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.
may show teardrop sign inferior wall fracture, make sure blood supply doesn’t get cuff off
what need to look for in b.o.f.
- 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 need to stitch quickly
- extraocular muscle entrapment: suspected if there is an acute change in angle of the muscle
- prolapse of orbital fat = enopthalmic eye (sitting back)
Indications for Surgery:
b.o.f.
- Potential indications for surgical repair include:
- significant enophthalmos (cosmetic)
- significant diplopia (professional snooker player / cylcist, elevation problem)
- muscle entrapment, especially with “trapdoor fracture” in children
- large area fractures
when is prompt intervention required?
(1) Orbital soft tissue entrapment generates the oculocardic reflex, with nausea, vomiting, bradycardia and syncope.
(2) A ‘white-eyed’ blow-out fracture is suspected. Young patients present with a history of periocular trauma, minimal bruising or oedema, marked limitation of elevation and CT scan evidence of an orbital floor fracture with tissue entrapment.
(3) A detachment of an extraocular muscle is suspected. Then urgent surgical intervention is indicated.
The above first two situations are often seen in children where the more flexible orbital bones cause the fracture to bend, crack and form a trapdoor. The incarcerated soft tissue held firmly by the trapdoor can quickly become ischaemic. Surgical release of the trapped tissue and repair of the fracture should be undertaken urgently.
what is Timing of surgery:
in b.o.f.
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
Clinical examination
in b.o.f.
- Vision
- Covert test
- Motility
- Fusion (increased vertical fusion?)
- Colour vision
- Ocular exam, cornea, retina etc
- Fields
mx non surgical for b.o.f.
In most patients with an orbital blow-out fracture, a better clinical evaluation can take place if time is allowed for the initial bruising and oedema to settle. During this period nonsurgical management of ocular muscle imbalance consists of:
(1) Encouraging the adoption of a head posture to achieve BSV.
(2) The use of Fresnel prisms.
(3) Occlusion.
The condition should be monitored mainly by assessment of VA, the Hess chart and field of BSV. The patient should be tested every 3–4 days for the first few weeks after the injury. As the soft tissue oedema and haemorrhage subside, ocular movement may improve and an initial proptosis may change to enophthalmos.
criteria for sx b.o.f.
Criteria for Surgery
Persistent limitation of ocular movement. Tissue incarceration or herniation. Significant enophthalmos.
