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.
What is the indication for an ORIF?
Ind: if unstable after reduction, comminuted, or other middle 1/3 #
How do you access the zygoma for ORIF?
- Upper lid → temporal process and supraorbital rim
- Subciliary → sphenoid process (infraorbital rim) and arch
- Buccal → maxillary process
- Bicoronal Approach → medial wall of orbit and zygoma
What are the complications?
Complications Early - Diplopia (usually resolves in 24hrs) - bleeding (retro-orbital haematoma) - nerve injury
Late
- plate infection, extrusion, migration
- scars,
- ectropion
- union problems
- sinus problems
How do orbital fractures occur?
- Often occur in conjunction with zygomatic fractures, nasoethmoid, high le Fort #s
- Isolated orbital # from pressure to the globe
Orbit fractures at its weakest
Adults - the inferomedial floor (lamina papyracea = paper layer)
Children - roof (emergency surgery)
What are the symptoms and signs?
- Bruising, swelling
- Subconjunctival haematoma with no post limit
- Palpable steps in orbital margin
- Enophthalmos - increase volume of orbit, ↓ volume of contents, intraorbital fat atrophy (late) – measured from lateral orbital rim using Hertel’s exophthalmometer
- Hypoglobus – downward displacement of globe
- Orbital dystopia – unequal orbit heights
- Diplopia - Entrapment of fat, fascial attachments or muscles within fracture lines, contusion of recti or oblique muscles. Usually on upward gaze as most # and tethering occur inferiorly.
PROPTOSIS = forward displacement of any organ. EXOPHTHALMOS = only applied to eye. (Some it define as proptosis secondary to endocrine causes) EXORBITISM = small orbital cup leading to protruded appearance of contents
What radiological investigations are indicated?
Site, extent and displacement
PA, OM (teardrop sign - fat herniating into maxillary sinus)
CT scan
3D CT reconstruction
What are the indications for surgery?
Symptomatic diplopia Significant enophthalmos Radiological evidence of orbital content entrapment Large bony defects Other fractures requiring fixation
What are the principles of surgery?
ACCESS Lower eyelid incision - explore and delineate # - release any trapped structures REDUCE fractures RECONSTRUCT orbital floor - Autologous vs alloplastic (see below)
Secondary reconstruction is very difficult!
What approaches are used?
Approaches
Cutaneous - subciliary / subtarsal / orbital rim
Skin / skin & muscle
Transconjunctival +/- lateral canthotomy
Pre-septal (avoid fat) vs post septal
Medial floor - Bicoronal vs Lynch (incision medial to medial canthus)
What materials are available?
Bone - split calvarium, Iliac crest, rib, antral wall, mandible
Cartilage - septal, ear, rib
Allogenic - banked bone, lyolysed cartilage
Alloplastic - resorbable (vicryl mesh) vs non-resorbable (e.g. Medpore, titanium mesh, Gore-Tex, Silicone)
What is
- Superior orbital fissure syndrome?
- Orbital apex syndrome?
- Entrapment of CN 3,4, frontal branch of 5, 6, nerve to levator palpebrae superioris
- Same as SOF + optic nerve CN2
Nasoethmoidal fractures
- Causes
- Symptoms and signs
- Trauma to interorbital region
- May be associated with other fractures (medial orbit, root of nose, ethmoid air cells)
- Bruising and swelling
- Palpable bony step
- Telecanthus (if medial canthal tendon detached)
- Enophthalmos
- Diplopia
What is the treatment of nasoethmoidal fractures?
- Access : Overlying lacerations, Bicoronal, Medial orbital incision (Lynch)
- Reduction : Elevate nasal bones, replace anatomically +/- bone grafts to reconstruct dorsum of nose.
- Fixation : Plates and screws to nasomaxillary buttresses, repair medial canthal tendon (plate / transnasal / bone fixation devices.
Lacrimal system not routinely explored
Frontal sinus fractures
- Causes
- Symptoms and signs
- blow to glabellar area
- Bruising, swelling, crepitus
- Palpable bony steps
- CSF rhinorrhoea
- Late signs - sinusitis, mucocoeles and meningitis
What is the management of frontal sinus fractures?
Priniciples
Anterior table vs Posterior table
Anterior table fracture
Displaced (op) vs non-displaced (observe)
Nasofrontal duct involved?
Yes → reduction, stabilisation, obliteration or cranialisation
No → reduction, stabilisation
Posterior table fractures (usu with ant table)
Displaced? no → CSF leak? no → observe
Displaced? no → CSF leak? yes → observe 7 days, then dural repair +/- cranialisation
Displaced? yes → CSF leak? Y/N → Nasofrontal duct involved →
No → reduction & stabilisation of anterior wall
Yes → reduction & stabilisation w obliteration / cranialisation
What techniques are used for frontal sinus fractures?
- Fixation plate / wire, may need calvarial bone graft if comminuted.
- Obliteration of sinus = complete removal of mucous lining, spontaneous osteogenesis or bone graft.
- Cranialisation = complete removal of mucous lining, plug the nasofrontal duct with bone graft, remove post wall, allows the brain and dura to advance to fill the defect.
What are the complications?
Can have serious consequences
- Meningitis
- Cerebral abscess
- Mucocoeles
- Osteitis
What structures does the nose consist of?
- nasal bones
- frontal processes of maxilla
- nasal cartilages
- nasal septum (quadrilateral cartilage, perpendicular plate of ethmoid, vomer)
What fracture patterns are observed?
Lateral force
- nasal bones, septum, lateral deviation of entire nasal complex
Head on force
- backward displacement and splaying of nasal bones → saddle deformity
- septal buckling / fracture +/- septal haematoma (must examine)
Nose = most common facial fracture
80% fractures occur at junction of thick & thin parts
parasthesia of nasal tip = anterior ethmoidal nerve injury
What is the blood supply of the nose?
- Anterior ethmoidal
- Posterior ethmoidal (both opththalmic)
- Sphenopalatine (maxillary)
- Greater palatine (maxillary)
- Branch of superior labial (facial)
How do patients present?
- Nasal swelling and bruising
- Haematoma extends from nose into the periorbital area
- Respiratory obstruction
- Epistaxis
- Change of bridge contour
- Nasal bridge skin, mucosal lacerations
- New asymmetry
- Septal injury, look for haematoma
- Untreated haematoma can lead to pressure necrosis of nasal septum
What radiological investigations may be required?
Xrays not always necessary - treat on clinical grounds
OM 45° view
CT if complex
What is the classification for nasal fractures?
Stranc and Robertson, Annals Plast Surg 1979
Lateral Impact
Plane 1
o Unilateral displacement of one nasal bone into the nasal cavity.
Plane 2
o Moderate medial (internal) displacement of ipsilateral nasal bone with some outward displacement of contralateral nasal bone
Plane 3
o Involve the frontal process of the maxilla at the piriform aperture on one side and are hemi-nasoethmoidal-orbital fractures
Frontal Impact
Plane 1
o Involve the distal ends of nasal bones, usually bilateral but worst on one side.
o Frontal impact nasal fractures involving anterior portion of nasal pyramid and septum.
o Disruption of cartilaginous septum
Plane 2
o Displace at least the lower half of both nasal bones and accompanied by some telescoping of septum. Almost always reduction in nasal height, with the bone decrease usually less than the height decrease of the cartilaginous septum.
Clinically → dorsal nasal hump.
o More comminution of the nasal pyramid and more dislocation of the septum
o Disruption of the bony septum and nasal bones
Type III (Plane 3)
o Involve frontal processes of maxilla = naso-orbitoethmoidal #
o Injuries extend beyond the nasal skeleton into piriform aperture and medial orbital rim
o Represent mild nasoethmoidal fractures.
How do you manage nasal fractures?
Appearance and function dictate Rx
Best to operate 5-7 days after swelling minimised (2 weeks = too set)
Assess for deviation or collapse of nasal bones
How is surgery performed?
Early vs Late Presentation
Early: Deviation vs Collapse
Deviation
- thumb pressure (reduce nasal bone that has been pushed out)
- Walsham’s nasal forceps (to reduce depressed side) - (use corrected sided forceps, rubber sleeve = skin side)
- disimpact with side - side mvmt
Collapse - nasal bone & septum injury
- Walsham’s septal forceps (Asch forceps) to straighten septum
- evacuate haematoma, quilt septum
- pack nostrils, nasal splint
- remove pack 48hrs, splint 1wk
Late presentation
- Open vs Closed reduction
- wait until inflammation settled before formal rhinoplasty
Maxillary fractures
What are the 3 vertical and 3 horizontal buttresses reinforcing the maxilla?
Vertical
- Nasomaxillary buttress - b/t cheek & nose
- Zygomatico-maxillary buttress - through body of zygoma up into lateral orbital rim and zygomatic arch
- Pterygopalatine buttress which passes posteriorly
Horizontal
- Zygoma
- Infra-orbital rim
- The alveolar arch
Le Fort fracture patterns are often asymmetrical.
What is a Le Fort 1 fracture?
line passes transversely across
1. base of piriform aperture
2. base of maxillary sinus
3. pterygoid plates
Pattern divides the maxilla into 2 segments. Lower segment = floating palate contains the alveolus, the palate and the pterygoid plates.
- horizontal fracture that separates alveolar and palatine processes from the body of the maxilla
What is a Le Fort 2 fracture?
aka pyramidal #
# line passes
1. across nasal bones
2. Into medial wall of orbit
3. Diagonally downwards and outwards through maxilla
4. Through pterygoid plates
The bony fragment contains: lacrimal crests, bulk of maxilla, piriform margin, alveolus and palate.
What is a Le Fort 3 fracture?
aka craniofacial dysjunction
# line passes
1. through nasofrontal suture
2. across orbital floor to ZF suture
3. through zygomatic arch and pterygoid plates.
This results in detachment of entire midfacial skeleton from cranial base. Sagittal # of maxilla and isolated # of alveolus may also occur
What are the symptoms and signs?
Bruising, swelling, Battle's sign Malocclusion Epistaxis Enophthalmos Diplopia Infraorbital nerve sensation ↓ Palpable step in bone / dentition Dish face deformity Mobile maxillary segment (stabilise glabella & distract alveolus)
- Alveolus alone = Le Fort I
- Alveolus and nasofrontal = Le Fort II
- Alveolus, nasofrontal region and ZF suture = Le Fort III.
What are the important investigations?
Identify site, extent and displacement. PA Waters = OM - shows # lines and fluid in sinus. CT scan 3D CT reconstruction
What is the treatment for maxillary fractures?
ORIF
Incisions
- bicoronal (nasofrontal, orbital walls, ZF suture, zygomatic arch)
- lower eyelid (orbital floor, infraorbital rim)
- upper buccal sulcus (lower maxilla)
Reduction
- Rowes distraction forceps / Tessier disimpaction forceps
- stabilised with IMF
Fixation
- temporary intermaxillary fixation
- interosseous wires
- mini plates & screws (1.5 - 2mm) (across maxillary buttresses)
- bone grafts
- external fixation
Mandibular fractures
2nd most common facial fracture
Location - usually >1 fracture e.g. condyle + parasymphyseal / angle Condyles 36% Angle 20% Body 20% Symphysis 14% Alveolus 4% Ramus 3% Coronoid Process 3%
Open fracture into mouth - cover w antibiotics
young - fight injuries 97%, elderly - falls
What are the symptoms and signs?
Airway obstruction
Pain
Swelling
Trismus
Malocclusion
Crepitus
Bruising → extra or intraoral (sublingual)
Palpable step → mandibular border/ dentition
Paraesthesia → inf alveolar / mental nerve
Chin deviated → side of fractured condyle
How are mandibular fractures classified?
Closed / compound (skin, buccal mucosa, tooth socket)
Anatomical location
Displacement
Comminution
What muscles act on the mandible?
Parasymphyseal fragment is pulled
- down by geniohyoids
- down and lat by digastrics
- back by genioglossus.
Body of mandible is pulled
- up by masseter
- up and back by temporalis
- back by pterygoids
What is favourable vs unfavourable fracture orientation?
Unfavourable
o fracture line slopes upwards and anterior from the lower border of the mandible,
o or slopes anterior and inwards in the transverse plane.
o inherently unstable because of the pull of the masseter, digastric and pterygoids (distracts the fragments)
What radiological investigations may help diagnosis?
OPG PA view - condyles Lateral oblique reverse Townes - condyles CT scan of little value if no other fractures
What are the indications for conservative vs ORIF?
Conservative
o Most Condylar fractures
o Stable undisplaced fractures, normal occlusion
o Minimal trismus
ORIF o Malocclusion o Pain that doesn’t settle o Mobile # fragments o Multiple # fragments o May get paraesthesia after surgery - NOT indication for ORIF
What pre-op measures are taken?
Consent - Numbness made worse, infection, plate problems GA Nasal Tube Throat pack Antibiotics Not muscle relaxed (more wobbly) Dexamethasone 8 mg single dose
What incisions are used for access?
Intraoral approach - Mucoperiosteal flap, protect mental nerve
Submandibular approach - for difficult fractures
Retromandibular approach (below ear)
Preauricular approach (esp TMJ)
How are mandibular fractures reduced?
Erich arch bars Bridle wire Ivy loops, Temporary IMF Senior assistant to hold Temporary IO wire
How are mandibular fractures fixed?
Miniplates and screws - Unicortical (not bicortical) to save the teeth roots
Can be ‘load-bearing’ or ‘load-sharing’ constructs
Load-bearing
- rigid plate bears forces of function at fracture site
- atrophic, edentuous, comminuted fractures
Load sharing
- lag screw / compression plating / mini-plate
- single fracture, good bone stock
External fixation - rarely used
Management of condylar fractures
Options
1. conservative
2. Elastic IMF for traction to correct lateral open bite
3. ORIF - indicated if
→ condylar head dislocated from the TMJ
→ condyle lateral displaced 30deg or more from the axis of the ascending ramus
→ in bilat # assoc w shortening of ascending ramus and open bite
→ Can’t get adequate occlusion with closed reduction
→ foreign body in TMJ (eg bullet)
→ poor compliance
How do you ORIF condylar fractures?
How do you treat TMJ dislocations?
Transparotid approach - condyle access
Risdon + preauricular incsion - high ramus fracture
Incise down to parotid capsule, then blunt dissection through gland (preserve CN VII)
Plate
TMJ dislocation - reduce by downward and backward pressure by thumbs placed on the posterior molar teeth under GA
What are the four vertical and five horizontal facial buttresses?
Vertical buttresses
- Nasomaxillary - alveolar process of maxilla (Canine) to frontal process of maxilla and nasal bones (i.e. medial to orbit)
- Zygomaticomaxillary - alveolar process of maxilla (opp 1st molar)to zygotic process of frontal bone (i.e. lat to orbit)
- Pterygomaxillary - post body of maxilla via sphenoid to skull base (including pterygoid plates)
- Mandibular - ascending ramus to skull via TMJ
Horizontal 1 Supraorbital bar 2 Infraorbital rim 3 Zygomatic arch 4 Maxillary (palate) 5 Mandibular (body of)
What are the 4 main processes of the maxilla?
Alveolar - becomes resorbed in edentulous pts
Frontal - supports nasal bones
Zygomatic - articulates with zygoma
Palatine - articulates with vertical / horizontal plates of palatine bone
What is the sensory nerves of the internal and external nose?
External
Trigeminal nerve
V1 - infratrochlear, external nasal nerves
V2 - infraorbital, anterior superior alveolar nerves
Internal
Trigeminal nerve
anterior ethmoidal (direct continuation of nasociliary nerve), infraorbital, posterior superior alveolar nerves
posterior superior nasal, greater palatine and nasopalatine nerves (via pterygopalatine ganglion)
