These diagrams and illustrations have been designed to help you learn, memorise and recall key information.
Zygomatic fractures can be likened to a chair with four legs (articulations/buttresses): -
A) Frontal - contributes to the lateral orbital wall
B) Sphenoidal (greater wing) – also contributes to the lateral orbital wall
C) Maxillary - contributing to the orbital floor
D) Temporal - contributing to the zygomatic arch
Usually zygomatico-maxillary fractures cause disruption at most of these points.
The zygomatic-frontal suture is the strongest and usually the last to fracture.
The zygoma is mal-positioned therefore in anetro-posterior, horizontal and vertical directions.
- Low-energy - less surgical expsoure is required.
- High-energy - comminution at each articulation (more surgical exposure is required).
NORTH & KNIGHT CLASSIFICATION
- Arch fracture
- Depressed body fracture
- Depressed body fracture (medially rotated)
- Depressed body fracture (laterally rotated)
- Comminuted fracture
- Lat. to limbus with no posterior limit.
Malar flattening (when viewed from above)
Step-off at orbital rims
Inferior displacement of lat. canthus
- Downward-sloping palpebral fissure
Trismus - if zygomatic arch abuts coronoid process.
Swelling, bruising & epistaxis
Enopthalmos or Dystopia
Diplopia on upward gaze.
CT (axial & coronal). To assess …
- Degree of comminution (High/low energy)
- Medial / Lateral rotation of zygoma
- AP position of zygoma
- Position of lat. orb. wall
- Need for reconstruction of orbital floor
Un-displaced fractures can be managed conservatively (with regular re-evaluation).
Sometimes they are stable following reduction and no fixation is required.
However, they are usually unstable due to the pull of the masseter.
For adequate reduction, at least 3 of 4 articulations must be assessed intra-op.
ACCESS INCISION FOR LOW ENERGY
Upper Lid blepharoplasty incision - to access ZF & ZS.
Buccal incision - to access ZM.
Lower lid incision not needed if ZF, ZS and ZM have been reduced.
ACCESS INCISION FOR HIGH ENERGY
Coronal flap enables wide exposure.
Resuspension of the malar soft tissues is key to prevent malar ptosis.
Orbital floor recon is more frequently needed (via lower lid incision).
ACCESS INCISION FOR ISOLATED ARCH FRACTURES
Isolated arch fractures are almost purely a cosmetic concern (although trismus can occur).
Can be reduced via a Gilles Lift (usually stable and fixation is not therefore required).
Often these fractures settle well following fixation.
Lower lid incision complications can occur though.
Infection (of the plate) / Extrusion / Migration.
Bleeding (including retro-orbital haematoma).
Scars (including ectropion of the lower lid).
Diplopia (can occur early & usually settles in 24hrs).
Nerve injury (infra-orbital / facial).
Permanent dentition is at risk with maxillary buttress screws.
Resorbable fixation systems are used when possible.