Midface Fractures
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Direct answer
René Le Fort dropped cadavers from heights in 1901 and mapped three reproducible separation planes of the midface: Le Fort I through the maxilla below the nose producing a floating maxilla, Le Fort II a pyramidal fracture from nasal bridge through the orbits to the maxillary buttresses, and Le Fort III total craniofacial dysjunction across the orbits and zygofrontal sutures. The modern exam, however, tests the midface by its functional units — zygomatic complex, orbit, nasoethmoid complex and the maxilla proper — because that is how surgery is planned: exposure of the correct buttresses and fixation at frontozygomatic, infraorbital and zygomaticomaxillary points.
What you must remember
- Le Fort I: horizontal maxillary separation with Guerin's sign — vestibular ecchymosis — and a mobile maxilla; Le Fort II: pyramidal, raccoon eyes, possible CSF leak; Le Fort III: craniofacial dysjunction, dish-face deformity, raccoon eyes and CSF rhinorrhoea.
- Zygomatic complex (tripod) fracture lines: frontozygomatic suture, infraorbital rim and zygomaticomaxillary buttress, and the arch; the quadripod adds the zygomaticosphenoid suture.
- ZMC clinical tetrad: malar flattening from above, infraorbital paraesthesia, diplopia, and trismus if the arch impinges on the coronoid or temporalis.
- Orbital blowout: floor medial to the infraorbital canal and lamina papyracea fracture from pressure blows; enophthalmos beyond about 2 mm, diplopia on upgaze, infraorbital hypoesthesia, and the teardrop sign of herniated tissue on imaging.
- Paediatric trapdoor floor fractures look white-eyed but trap muscle, causing pain and bradycardia on ocular movement — the oculocardiac reflex makes this an urgent operation.
- Orbital repair triggers: persistent symptomatic diplopia, enophthalmos of 2 mm or more, a defect of roughly half the floor or more, and acute entrapment — adults within about two weeks, trapped children within a day or two.
- Nasoethmoid (NOE) injuries: telecanthus from displacement of the medial canthal tendon-bearing fragment (normal intercanthal distance 30-35 mm), nasal bridge depression, CSF leak; repair by transnasal canthopexy.
- Approaches: subciliary, subtarsal or transconjunctival for the floor; gingivobuccal for the buttress; upper blepharoplasty for frontozygomatic; coronal for NOE and widely displaced ZMC.
A worked ZMC case
A 28-year-old struck with a bat has left cheek depression, numbness of the left cheek and upper lip, double vision looking up, and deranged occlusal contact on the left. Work the plan. Examine before the swelling hides everything: bird's-eye view for malar flattening, step at the frontozygomatic suture, infraorbital rim step, V2 sensation, forced duction test where entrapment is suspected, documented acuity, and intraoral palpation of the buttress. CT with 3D reconstruction, including coronal orbital reformats for the floor defect. Classify the displacement: medially or laterally rotated, or arch-only. Plan fixation points — at minimum frontozygomatic and zygomaticomaxillary buttress (two-point), adding the infraorbital rim (three-point) when the orbit is involved, or the arch via a coronal or Gillies approach. Sequence: restore the arch and malar prominence, plate the frontozygomatic suture, then the buttress, then explore the floor through a transconjunctival incision once the rim is reduced, reconstructing it with titanium mesh, porous polyethylene or bone graft; recheck diplopia and canthal position at the end. Post-operative eye observations, no nose blowing, and review — most upgaze restriction from oedema resolves, and persistence beyond weeks needs squint evaluation.
Where students slip
The orbital floor is where candidates lose their footing. They either operate on every floor crack — small linear cracks without entrapment, enophthalmos or diplopia are observed — or they miss the trapped child whose eye looks quiet while the muscle is ischaemically incarcerated; the latter error causes permanent diplopia and is heavily penalised. The second slip is telecanthus timing: NOE canthal repair is far easier primarily than secondarily, because once the tendon-bearing fragment heals displaced, revision needs osteotomy and grafting — "refer, it will settle" is the wrong reflex. The third is forgetting that Le Fort fractures are frequently asymmetric or combined; reciting the textbook drawing while the CT shows a mixed pattern is the gap the examiner probes.
Frequently asked questions
What distinguishes a Le Fort II from a Le Fort III fracture?
Le Fort II separates a pyramidal central midface block from nasal bridge through the medial orbits; Le Fort III detaches the entire midface through the lateral orbits and zygofrontal sutures — craniofacial dysjunction.
What are the three components of a ZMC (tripod) fracture?
Frontozygomatic suture, infraorbital rim-zygomaticomaxillary buttress, and the arch (the zygomaticosphenoid suture completes the quadripod).
Which orbital floor defects warrant reconstruction?
Enophthalmos of 2 mm or more, persistent symptomatic diplopia, defects spanning roughly half the floor, and acute entrapment — paediatric trapdoors urgently.
What produces telecanthus in NOE fractures?
Displacement of the fragment bearing the medial canthal tendon, widening the intercanthal distance beyond its normal 30-35 mm; repair reattaches it transnasally.
How is CSF rhinorrhoea confirmed?
The halo ring on gauze as a screen, definitively beta-2 transferrin assay — with neurosurgical involvement and no blind nasal packing.
Which incisions expose the orbital floor?
Subciliary, subtarsal and transconjunctival — the last often with lateral canthotomy — chosen by ectropion risk and preference.