CHAPTER 03: MAXILLOFACIAL Flashcards
What are the principles of maxillofacial trauma?
- accurate diagnosis
- ideally early single stage surgery
- thorough exposure of bony fragments
- precise rigid fixation (+/- bone graft if ned)
- reconstruction and resuspension of soft tissue
Who classified dental occlusion?
ANGLE CLASSIFICATION (Edward Angle) - System for describing dental occlusion in the AP plane. It does not say which is malpositioned or the cause of malocclusion.
- The upper 1st molar is the point of reference in describing the AP relationship of mandible and maxilla.
Class I occlusion:
- Mesiobuccal cusp of upper 1st molar articulates within mesiobuccal groove of lower 1st molar.
Class II malocclusion:
- lower 1st molar is distal to upper 1st.
- II1: upper anterior teeth are flared forward
- II2: anterior upper and lower teeth are retruded with overbite.
Class III malocclusion: CLEFT
- lower dentition is positioned mesial (toward middle of front of jaw) to upper dentition.
(Class I = normal 1-2 mm overjet and 1-2 mm over bite - Overbite = vertical - Overjet = horizontal Class II o Div 1 = overjet but normal overbite o Div 2 = overjet and overbite Class III o zero to negative overjet)
Name the cross-sectional layers of the temporal area
- Skin
- Sc fat
- Temporo-parietal fascia (frontal branch of facial nerve)
- Deep temp fascia (divides into 2)
- superficial layer of DTF
- superficial temporal fat pad
- deep layer of DTF - Deep temporal fat pad
- Temporalis muscle
- Periosteum
- Cranium
What is the safe approach to zygomatic arch from the temporal area?
- Skin incision.
- Subaponeurotic plane.
- 2cm above zygomatic arch → pierce superficial layer of deep temporal fascia → temp fat pad → arch.
History
AMPLE Hx
- Allergy, Meds, PMH, Last meal, Events
Of the injury
- When? What happened?
- What has been done since
- Pattern of injury is related to amount of energy dissipated by the tissues
- Place, Conditions
Of the patient
- Previous injuries (eyes)
- facial, other
- Anything affecting treatment &/or injuries
- Medication, Allergies, Tetanus status, etc.
- Social History, Occupation
Examination
Airway management techniques
Early initial emergency examination and concomitant treatment according to ATLS
Airway - (tongue, impacted mid 1/3)
Airway management techniques
o Simple clearance and posture
o Barrel bandage
o Tongue suture (or towel clip)
o Distract mandible forwards to support tongue
o Airway may be improved by reducing fractures by relocating the maxilla upwards and forwards
o Nasopharyngeal airway (check patency regularly)
o Intubation
o Laryngotomy - cricothyroidotomy
o Tracheostomy
After assessment of Breathing, how do you manage Circulation and Haemorrhage Control?
Reduction may stop bleeding,
Beware of scalp bleeds/ ICA → tonsillar fossa
In theatre
- percutaneous K-wires to fix fracture
- Facial bandaging → pack mouth, nose, face
- Clamping / ligating
- Nasal haemorrhage → adr packs
- may need post nasal packs
- bite blocks
- Balloon / Foley catheters
- interventional radiology - embolisation of ECA
- Ligation of ECA
Glasgow Coma Scale
Best Motor Response 6 Obeying 5 Localizing 4 Withdraws 3 Flexing (Decorticate) 2 Extending (Decerebrate) 1 None
Best Verbal Response 5 Oriented 4 Confused conversation 3 Inappropriate words 2 Incomprehensible sounds 1 None
Eye Opening 4 Spontaneously 3 To Speech 2 To Pain 1 None
How do you examine the upper face?
What do you need to assess in the mid face?
Overall Inspection - upper, mid, lower face
Neck Examination
Cranial Nerves
Upper face
- Forehead sensation
- Crepitus = frontal sinus #
- CSF rhinorrhoea (ant cranial fossa #)
Mid Face
- Orbits
- Zygoma
- Nasal bones
- Maxilla
Mid face: How do you examine the orbits?
- Orbits
- racoon eyes
- exorbitism, enophthalmos
- ocular dystopia
o Limited upward gaze = orbital floor #
o Limited lateral gaze = medial wall #
o Oedema can reduce ROM
- tenderness / depression of orbital walls
- diplopia, visual fields
- pupils
- intercanthal dist (medial canthal tendon instability = naso-orbital or ethmoid frac)
- superior orbital fissure syndrome, orbital apex syndrome
Mid face: How do you examine the zygoma, nasal bones & maxilla?
- Zygoma
- Fractures often present with orbital signs
- Malar flattening from above
- Palpable step
- Trismus - Nasal bones
- Palpable deformity and tenderness
- Septal deviation and haematoma (drain) - Maxilla
- paraesthesia of cheek, upper lip → orbital floor fracture, infraorbital nerve
- Malar flattening
- Increased maxillary mobility
o max alveolus moves but nasofrontal area does not → Le Fort I
o max alveolus and nasofrontal moves → Le Fort II
o entire face moves → Le Fort III
o but # may be impacted → no movement
How do you examine the lower face?
- Mandible
- Occlusion
- Trismus
- Lower lip numbness (inf alveolar nerve inj)
- TMJ tenderness - ? # condyle
2. Oral Cavity o Malocclusion- what is their normal bite? - Are teeth numb? o Palatal bruising - ?Le Fort 1 # o Palatal split? o Tender zygomatic buttress - ? Zygomatic-mandibula complex (ZMC) #
- Laryngotracheal injury (cricoid/thyroid c#)
- Ears
- Haemotympanum / perf = ?skull base #
- Bruised canal = ?condylar #
- Signs of middle cranial fossa #
o CSF otorrhoea
o Battles sign - Soft tissue injuries
- facial nerve, parotid duct
What other considerations are there in H&N trauma?
Head
- other bruises, lacs
- cranial nerves
- ophthalmoscopy
- GCS
Intracranial bleed
C-spine
Body
Extremities
What is the principles of treatment?
Early
- Debridement
- Closure of lacerations
- Temporary immobilisation of displaced/mobile mandibular fractures
Definitive
- Fractures / soft tissues
- Reduction
- Fixation / Immobilisation
- Restoration of function
What is the timing for surgery?
What are the treatment options?
Early
Delayed primary (10days)
Secondary (increased scarring & difficult to realign bones)
Options
- no active Rx
- Indirect fixation
- Direct fixation
What are the indirect fixation options
IMF = Inter Maxillary Fixation Eyelet wires Arch bars Cast splints Percutaneous pins Head frames
Advantages = simple, precise occlusion attainable, can avoid G.A.
Disadvantages = immediate post op airway compromise (may need trache), uncontrolled reduction, esp in mid 1/3 #, can be displaced
What are the direct fixation options?
Access → Reduction → Fixation
- visualise reduction and fixation with small metal plates or wires.
Advantages = accurate diagnosis + reduction, +ve fixation, fast healing, early function
Disadvantages = requires GA, technically demanding, extra-oral approaches leave scars, VII nerve damage possible
What are the investigations of choice in maxillofacial trauma?
CT scan (+/- 3D) OPG = orthopantomogram (teeth)
Mandibular fractures
- OPG
- PA mandible (open and closed)
- Lateral oblique (anterior or posterior)
- Reversed Towne’s view (condyles)
Middle 1/3rd, including zygomaticomalar complex
- OM 15 + 30
- Rotated OM
- Submento-vertex
- PA orbits
- Lateral jaws
What incisions are used?
- Existing lacerations.
- Bicoronal.
- Lower eyelid incision.
a. transconjunctival
b. sub-ciliary
c. mid-lid incision
d. junction of eyelid and cheek. - Upper or lower buccal sulcus incision.
- Dingman’s lateral brow incision.
- Risdon’s retromandibular incision = submandibular approach (2cm below angle of mandible, nerve = deep to platysma).
- Lynch’s medial canthus incision
- Gilles incision within hairline of temple.
Where is the marginal mandibular nerve?
Dingman and Grab 1962
- cadavers’ nerve below up to 1.5 cm
- but on live dissection minority have nerve below ramus.
- 2 fingers – safe, usually 2 branches
- Nerve is always above ramus anterior to the facial artery.
What are the advantages of mini plate osteosynthesis?
Accurate anatomical reduction Avoidance of IMF Airway problems Early return to function Especially useful in complex and edentulous mandibular fractures
What are the complications of mini plate osteosynthesis?
Complications Haematoma Dysocclusion Infection Suture dehiscence Plate infection Neuropraxia Tooth damage
What are the anatomical landmarks and planes?
SEE PICTURE!
Ricketts E-Line = pronasale to pogonion =
Nasal tip to most protruding point of chin
Angles - NL = 90-110 - Sella-Nasion: occlusal relationship of SNA - upper teeth SNB - lower teeth
Facial Planes
Frankfort horizontal plane:
- plane intersecting right and left poria and left orbitale.
- Orbitale (Or), lowest point on margin of orbit
- Porion (P), midpoint on upper edge of external auditory meatus
Mandibular Plane:
- Gonion (Go), point on angle of jaw that is most inferiorly, posteriorly, and outwardly directed
- Menton (Me), lowest point of contour of mandible symphysis
Facial Plane:
- Glabella to Pogonion
Where is the zygoma?
How does a zygoma fracture tend to occur?
Zygoma forms cheek eminence & inferolateral border of orbit
tend to occur in a tetrapod fashion at jtn
- zygomatic process of the frontal bone at the zygomaticofrontal suture (ZF)
- greater wing of sphenoid in the lateral orbit
- maxilla in the orbital margin, orbital floor and anterior wall of max sinus
- temporal bone in the zygomatic arch
What are the usual fracture patterns?
- Simple
o # line down from infraorbital foramen.
o Displacement usually medial with medial or lateral tilt and impacted.
o Infraorbital nerve compressed in canal
o Branches of superior dental nerve cross # = numb teeth - Comminuted
o simple + floor of orbit comminuted and depressed
o Herniation of orbital fat (like blow-out #) - Zygomatic Arch #
o Localised depression of arch
o Medial depression → impinge on coronoid process → trismus
How are zygomatico-orbital fractures classified?
Classification of Zygomatico-orbital Fractures
- Undisplaced
- Arch # only
- Tripod # and ZF suture intact
- Tripod # and ZF suture disruption
- Pure blowout #
- Orbital rim #
- Comminuted and other #
What is the clinical picture of a zygoma fracture?
LOOK - swelling and bruising, conjunctival haem, malar flat, enophthalmos
FEEL - tenderness, step, # mobility
MOVE - trismus, dystopia
How do zygoma fractures present?
- Swelling and bruising
- very variable, external or intraoral
- Subconjunctival haemorrhage lateral to limbus = orbital fat bleed - Alteration of bony contour
- Malar depression Flattening of cheek prominence, step in infraorbital margin at infraorbital foramen - Sensory Loss
- teeth = sup dental nerve
- upper lip and alar = infraorbital n - Enophthalmos (look from above)
- Reduced orbital fat vol → herniated into antrum → posterior displacement of globe - Dystopia - Alteration of position of orbit and its contents.
i. Lateral dystopia
ii. Vertical dystopia
iii. Combination of lateral and vertical - Diplopia = double vision
- Usually looking up, may be transient caused by entrapment of inferior rectus muscle. Tethering of the orbital contents within the fracture lines can be detected with the forced duction test - Decreased visual acuity
- ?retinal detachment - Trismus + restricted lateral mvmt mandible
- Epistaxis - tear in mucosal lining of the max sinus
What do investigations show?
Xray - AP, lat 30° OM view (Waters), 60° OM view - Lines of Dolan and Elephants of Rogers Caldwell views - ZF suture Blood in antrum Look for irregularities / fractures near infraorbital foramen, zygomatic arch & lat wall of antrum
CT - depressed orbital floor, fat hernation
What are the fracture patterns of zygoma?
ZF Suture
Infraorbital rim
Zyg Arch - may # in 2 places
Buttress
How do you manage zygoma fractures?
Conservative - stable, undisplaced, review
Surgery - numb, trismus, diplopia, enophthalmos, deformity
Isolated infraorbital anaesthesia should be elevated or may get neuralgia
Simple # or arch # = temporal reduction
Comminuted # = direct exposure and fix
Most need plating to avoid recurrence of malar flattening (unstable due to pull of masseter)
What is the indication and how do you perform a temporal reduction (Gilles’ lift)?
Ind = pure displaced zygomatic arch # Deep temporal (temporalis) fascia is attached to upper border of zygomatic arch, temporalis muscle runs under.
- 2cm oblique skin incision over temporalis (radial) – in hair-bearing skin
- Avoid superficial temporal vessels, go through temporoparietal fascia (superficial temporal fascia) and follow plane until 2cm above zygoma.
- Incise white superficial layer of deep temporal fascia (temporalis fascia) to sup temp fat pad (frontal nerve above this)
- slide Bristow elevator in this plane, down behind the arch and then lever outwards – champagne cork snap on reduction.
DO NOT pivot elevator on temporal bone.
