CT Findings - What You're Operating On

• Bilateral Le Fort I - horizontal separation of alveolar arch from midface
• Left-sided Le Fort II - pyramidal fracture through nasal bones, left inferior orbital rim, left maxillary sinus wall
• Left ZMC (Zygomaticomaxillary Complex) fracture - disruption at ZF suture, infraorbital rim, zygomatic arch, and sphenozygomatic suture with inferolateral displacement and increased orbital volume
• Comminuted NOE (Naso-Orbito-Ethmoid) fracture - nasal bridge collapse, medial orbital wall disruption, likely Markowitz Type III
• Sagittal maxillary fracture - vertical midline palate split

OT VIVA - Complete Question Bank

SECTION 1: IMAGING & DIAGNOSIS

3D CT reconstruction (volume rendering). The views provided are frontal (AP), bilateral oblique, and left lateral projections. These allow visualization of major fracture lines, displacement, and bone relationships. For detailed assessment of orbital walls and comminution, axial and coronal 2D cuts are superior.

High-resolution CT scan with 3D reconstruction (1 mm cuts). It identifies fracture pattern, displacement, involvement of orbital walls/floor, sinus pneumatization, and guides plate positioning. 3D CT has replaced plain films and panoramic tomography as the gold standard for complex midfacial injuries.

3D CT showing a complex comminuted midfacial fracture with: bilateral Le Fort I horizontal maxillary separation; left-sided Le Fort II pyramidal fracture involving the nasal bones and infraorbital rim; left ZMC fracture with inferolateral displacement of the malar eminence; severely comminuted nasal/NOE complex with posterior collapse of the nasal bridge; sagittal maxillary split; and increased left orbital volume suggesting a risk of post-operative enophthalmos.

The mechanism of injury likely involved a directed impact to the left midface (e.g., motor vehicle accident, direct blow). High-energy unilateral impacts can produce the asymmetric Le Fort pattern seen here. The right zygomatic arch and frontal area appear intact on 3D reconstruction, though subtle non-displaced fractures may still be visible on 2D cuts.

SECTION 2: ANATOMY

All three Le Fort fractures involve fracture through the pterygoid plates (posterior maxillary walls) - this is the constant feature.

• Le Fort I: Horizontal, above the dentition; separates alveolar arch from rest of face. Crosses nasal septum, posterior maxillary walls, and pterygoid plates.
• Le Fort II (pyramidal): Through nasal bones at nasion, infraorbital rims, maxillary sinuses, hard palate, pterygoid plates.
• Le Fort III (craniofacial dysjunction): Through nasofrontal suture, medial and lateral orbital walls, zygomatic arches - complete separation of midface from cranium.

The four articulations of the zygomatic bone:

1. Zygomaticofrontal (ZF) suture - lateral orbital rim
2. Infraorbital rim / Zygomaticomaxillary (ZM) suture - inferior orbital rim and anterior maxilla
3. Zygomatic arch - zygomaticotemporal junction
4. Sphenozygomatic suture - lateral orbital wall (deep) These are the four-point fixation sites. Stability after reduction determines how many sites need plating.

Branch of V2 (maxillary division of trigeminal nerve). Traverses the infraorbital canal and exits through the infraorbital foramen (4-6 mm below the orbital rim). In left ZMC and Le Fort II fractures, the nerve is compressed or entrapped, causing hypoesthesia/paresthesia of the left cheek, upper lip, lateral nose, and upper teeth. This is a major surgical decompression indication.

The Naso-Orbito-Ethmoid complex consists of: nasal bones, frontal processes of maxilla, lacrimal bones, ethmoid complex, and the medial canthal tendon (MCT) insertion on the anterior lacrimal crest. Fracture causes posterior collapse of the nasal bridge, traumatic telecanthus (widened intercanthal distance), and flattening of the nasal dorsum.

• Type I: Single central bone fragment with intact MCT insertion
• Type II: Comminuted fracture but MCT remains attached to a recognizable fragment
• Type III: MCT insertion site is comminuted/unrecognizable - the most severe type requiring transnasal canthopexy

SECTION 3: APPROACHES & INCISIONS

Given the combination of fractures:

1. Coronal (bicoronal) incision - access to frontozygomatic suture, zygomatic arch, NOE complex, frontal bone
2. Upper eyelid / blepharoplasty incision (lateral orbital rim) - lateral ZF suture fixation; hides well in the lid crease
3. Transconjunctival (lower lid) incision ± lateral canthotomy - orbital floor, infraorbital rim access; pre- or postseptal approach
4. Gingivobuccal sulcus (intraoral) incision - Le Fort I level; anterior maxillary wall, piriform aperture, ZM buttress; must avoid infraorbital nerve
5. Gillies approach (temporal hairline) - closed elevation of zygomatic arch; instrument passes beneath temporalis fascia, over the muscle, beneath the arch

A stab incision is made within the temporal hairline, 2.5 cm above the zygomatic arch. Dissection proceeds beneath the superficial layer of the deep temporal fascia (SDTF) but above the temporalis muscle. The Gillies elevator is then passed medially underneath the depressed zygomatic arch. The reason: the SDTF inserts on the arch, whereas the temporalis muscle passes beneath it. Staying above the muscle but below the fascia creates a safe plane that places the instrument directly beneath the arch without entering muscle bulk.

Closed reduction of a depressed ZMC fracture through an intraoral (gingivobuccal) approach. An instrument (e.g., periosteal elevator or bone hook) is introduced through a mucosal incision and positioned under the zygomatic body, then elevated anterolaterally to reduce the fracture. This is used for simple, non-comminuted fractures.

A transcutaneous lower eyelid incision placed 2-3 mm below the ciliary margin. Access to infraorbital rim and orbital floor. Complications: ectropion (most common), lower lid retraction, scarring, scleral show, injury to orbicularis - higher risk than transconjunctival approach. A Frost stitch (temporary tarsorrhaphy to forehead) is placed at closure for 24-48 hours to reduce lid malposition.

A combined intraoral and endonasal approach allowing wide subperiosteal elevation of the entire midface without external skin incisions. Mucosal incisions in the gingivobuccal sulcus (bilateral) are combined with intercartilaginous and nasal floor incisions to "deglove" the midface soft tissues off the skeleton. Used for extensive midface surgery. Risk: nasal stenosis (vestibular mucosal incisions may scar).

SECTION 4: ANESTHESIA & AIRWAY

This patient has an NOE fracture with comminuted nasal bones and potential cribriform plate involvement. Blind nasotracheal intubation risks: passing the tube intracranially through a cribriform plate fracture, epistaxis obscuring the airway, dislodging nasal fragments, and further disrupting fragile nasal architecture. Oral intubation (via nasal tube conversion to submental) or surgical airway is preferred.

For a panfacial fracture needing occlusion check and full midface access:

• Submental intubation is the gold standard - allows nasal and oral access while maintaining occlusion check intraoperatively
• Tracheostomy if prolonged postoperative airway control is needed or submental is not feasible
• Oral RAE tube if dental occlusion check is not needed (compromises intraoral access)
• Nasal intubation is avoided in NOE/Le Fort II/III patterns

An oral RAE or armored tube is first placed orally, then the connector is detached. A stab incision is made in the submental region (paramedian, medial to the anterior belly of digastric). Blunt dissection through mylohyoid muscle, and the tube is then passed through this tunnel into the floor of mouth. The connector is reattached extraorally. This clears the oral cavity for dental occlusion assessment and the nose for NOE access without tracheostomy.

SECTION 5: OPERATIVE SEQUENCE (Critical Question)

The principle is: "top to bottom, outside to inside" (or inside to outside - depends on institution). The most commonly taught sequence:

1. Establish reference points first - start where bony anatomy is intact (e.g., intact frontal bone, ZF suture)
2. Cranial-to-caudal sequence: Frontal/NOE - Orbital rims - Zygomatic arch - ZMC body - Infraorbital rim - Le Fort II/III level - then Le Fort I
3. Establish occlusion (IMF) at Le Fort I level last, using dental relationships as the final check
4. Alternatively: establish occlusion first with IMF, then work from Le Fort I up (bottom-to-top) - this sequence is used when mandibular occlusion is the primary reference

Intermaxillary Fixation - temporary fixation of maxilla to mandible to establish correct dental occlusion during surgery.

• Arch bars (Erich arch bar): most common; wired to teeth; rubber elastics or wire ties
• IMF screws (cortical bone screws placed in alveolus): faster, less trauma to hands, but cannot be used in edentulous patients
• Ernst ligatures: simple wire loops around individual teeth
• Gunning splints: acrylic splints for edentulous patients

SECTION 6: IMPLANTS & FIXATION

• Le Fort I level (maxillary buttress): 1.5-2.0 mm miniplates (titanium); typically 4-hole L or straight plates at ZM buttress bilaterally and piriform aperture
• Le Fort II / orbital rim: 1.0-1.5 mm microplates/miniplates at infraorbital rim
• ZF suture (lateral orbital rim): 2.0 mm mini plate (higher stress)
• Zygomatic arch: 1.5 mm miniplates or absorbable plates
• NOE/nasal: 1.0 mm microplates; medial canthal tendon repaired with transnasal wiring (26-28 gauge)
• Orbital floor reconstruction: titanium mesh or porous polyethylene (Medpor) or resorbable sheets

The vertical buttresses are the main load-bearing pillars of the midface skeleton:

• Nasomaxillary buttress (medial vertical): piriform aperture to frontal bone
• Zygomaticomaxillary buttress (lateral vertical): ZM suture up to zygomatic process of frontal bone - the most important for occlusal force transmission
• Pterygomaxillary buttress (posterior) Horizontal buttresses: infraorbital rim, palate, zygomatic arch. ORIF reconstructs these buttresses to restore facial height and projection.

Champy's lines (ideal osteosynthesis lines) define the tension zones of the mandible where single monocortical plate fixation is biomechanically sufficient. Primarily apply to mandibular fractures (relevant if this case also involves a mandibular fracture). For the midface, load-bearing fixation at the buttresses is the analogous principle.

SECTION 7: COMPLICATIONS

• Enophthalmos (persistent) - if orbital volume is not adequately restored
• Diplopia - from muscle entrapment (inferior rectus, inferior oblique) or inadequate release
• Infraorbital nerve injury - hypoesthesia
• Lower lid malposition - ectropion, retraction (especially with subciliary approach)
• Implant migration or extrusion
• Infection / sinusitis
• Blindness (rare, from retrobulbar hemorrhage or optic nerve injury during dissection) - always perform forced duction test before and after repair

A forced duction test is performed under anesthesia. The inferior rectus muscle is grasped through the conjunctiva with toothed forceps, and the globe is rotated superiorly. Restriction indicates entrapment of the inferior rectus or periorbital fat in the fracture. It is performed:

• Before orbital floor repair (to confirm entrapment)
• After repair (to confirm complete release) A positive preop + negative postop result confirms successful decompression.

Widening of the intercanthal distance (ICD) due to lateral displacement of the medial canthal tendon with the NOE fracture fragment. Normal ICD is approximately 30-35 mm (roughly half the interpupillary distance). Management: transnasal canthopexy - the MCT or its bone fragment is reduced and secured with 28-gauge wire passed through a drill hole in the nasal bones, crossing to the contralateral side, and tightened. If Markowitz Type III (comminuted MCT site), the tendon itself must be identified and directly attached.

• Infection/osteomyelitis (esp. with sinus involvement)
• Malunion/malocclusion - if occlusion not re-established correctly
• Non-union (rare)
• Plate exposure or extrusion (hardware failure)
• Nerve injury: infraorbital (most common in midface), facial nerve branches (if not careful around zygomatic arch and temporal approach)
• Salivary fistula
• Scarring (if skin approaches used)
• Postoperative facial asymmetry
• Epiphora / lacrimal injury (medial orbit dissection)

SECTION 8: KNIGHT & NORTH AND ZINGG CLASSIFICATION (for ZMC)

• Group I: Undisplaced fractures - no treatment
• Group II: Zygomatic arch only
• Group III: Unrotated body fractures (ZMC displaced en bloc)
• Group IV: Medially rotated body fractures
• Group V: Laterally rotated body fractures
• Group VI: Complex/comminuted fractures This patient has a Group VI fracture.

• Type A: Isolated fracture of one zygomatic buttress (arch, or one suture)
• Type B: Complete mono-fragment ZMC fracture (all 4 sutures disrupted but single fragment) - most common
• Type C: Multi-fragment (comminuted) ZMC fracture This patient has a Type C fracture.

SECTION 9: TIMING AND DECISION MAKING

• Immediate (within 24-48 h): if airway compromise, vascular injury, open fractures with contamination risk, or trapped orbital contents (white-eyed blowout)
• Early (5-10 days): most midface ORIF is done after initial swelling subsides but before fibrosis sets in. This is the preferred window
• Delayed (beyond 2-3 weeks): fibrous union begins; surgery becomes more difficult, requiring osteotomies This patient appears to be planned for early ORIF (day of admission or within the week)

• Intracranial injury (always rule out with neurosurgery clearance)
• Ongoing bleeding / coagulopathy
• Airway instability not yet controlled
• Comorbidities (e.g., alcohol intoxication, metabolic derangement)
• Allow swelling to partially subside for better tissue handling and landmark identification

• Early repair (<2 weeks) is indicated for: large defects >50% of orbital floor, enophthalmos >2 mm, persistent diplopia with confirmed entrapment on CT
• Urgent repair (<48 h): "white-eyed" blowout in children (oculocardiac reflex, linear trapdoor fracture with tissue entrapment)
• Conservative approach for small defects with no entrapment

SECTION 10: RAPID-FIRE / HIGH-YIELD QUESTIONS

Facial nerve (VII) - specifically the frontal/temporal branch, which crosses the zygomatic arch approximately 1.5 cm anterior to the tragus, superficial to the periosteum. The coronal flap is elevated in a subgaleal or subperiosteal plane; at the temporal region, dissection must stay below the superficial temporalis fascia (subfascial dissection) to protect this branch.

Supraorbital neurovascular bundle - exits the supraorbital notch/foramen. Must be identified during elevation of the coronal flap off the frontal bone. If it exits via a foramen (not a notch), an osteotomy may be needed to free it.

Vagal reflex triggered by traction on extraocular muscles (especially medial rectus) or pressure on the globe. Causes bradycardia/asystole. Relevant during: orbital floor dissection, forced duction testing, placement of orbital implants. Management: release the stimulus immediately, atropine, inform anesthetist preoperatively.

• Palpation of the malar eminence for symmetry
• Check all fixed suture points (ZF, infraorbital rim, arch) for step-off
• Forced duction test (orbital floor)
• Intraoperative fluoroscopy or C-arm
• Correlation with contralateral (intact) side anthropometry

• First-generation cephalosporin (e.g., Cefazolin 1-2g IV) at induction for clean-contaminated cases
• If sinuses or oral mucosa are opened: cover gram-positives, anaerobes, and gram-negatives
• Consider adding Metronidazole for anaerobic coverage (intraoral approach)
• Duration: single prophylactic dose at induction, with one or two postoperative doses in complex contaminated cases

René Le Fort (French surgeon, 1901) described these fracture patterns after experimentally traumatizing cadaver heads by dropping them from heights and striking them with blunt objects. He identified three reproducible fracture levels that he called I, II, and III. This classification, now over 120 years old, remains the clinical standard despite being based on cadaveric experiments.

The concept recognizes that the face has vertical and horizontal structural pillars. Restoring facial height requires reconstruction of the vertical buttresses (ZM and nasomaxillary buttresses), while facial width and projection are restored by the horizontal buttresses (infraorbital rims, zygomatic arches). In panfacial fractures, all pillars must be anatomically reduced and fixed before soft tissue closure.

• Cummings Otolaryngology Head and Neck Surgery (Ch. 20 - facial trauma classification & surgical approaches)
• Bailey & Love's Short Practice of Surgery, 28th Ed. (Ch. 31 - zygomatic fractures, ORIF techniques)
• Miller's Anesthesia 10e (airway management in facial trauma)
• Tintinalli's Emergency Medicine (Le Fort classification, airway protocols)