Cummings Chap 23 Maxillofacial Trauma

10/31/12

Anatomy/PhysiologyUpper 1/3• Frontal bones- “relates” to FS, brain, orbits,

cribiform, supratrochlear/supraorbital nMiddle 1/3• Zygoma- facial projection, masseter insertion,

inferolateral orbital rims/walls• Orbits- 7 bones (frontal, zygomatic, max,

lacrimal, ethmoid, sphenoid, palatine).• maxilla- V2, infraorbital rims/floors, NLD, teeth,

MCL• nose- breathing/olfaction, cosmesis– Most freq fx bone in human body

Anatomy/Physiology

Lower 1/3• Mandible – Dentition/occlusion– Horseshoe shape + TMJ absorbs force from transmitting to

MCF– 32 teeth, 8/quadrant– Angel Classification of occlusion

• Class I mesiobuccal cusp of max 1st molar sits in buccal groove of the mandib 1st molar.

• Class II max molar more anterior/chin retruded- overbite• Class III max molar more posterior/chin prognathic- underbite

Eval/DiagnosisPE• ABCD, gen appearance, CNs, Blood/CSF, FBUpper 1/3• Test motor, sensation, step offsMid 1/3• Eval globe/orbits, visual acuity, EOMs,

proptosis/enopthalmos, ophthal consult• Nasal bone- fx, septal hematoma, NOE• NOE fx- Intercanthal distance- normal 30mm, ½

interpupillary distace, >45mm=telecanthus, loss of nasal dorsal height, epicanthal folds, MCL traction test

Lower 1/3• Open mucosal teas, V3 sensation, occlusion, mouth

opening/trismus.

Radiographic Eval

Axial cuts- good to eval FS, zygomatic arch, vertical orbital walls, vertical structures

Coronal cuts- good to eval orbital roof/floor, pterygoid plates, horizontal structures

CT face w/ fine cuts 1.5mm

SchemasUpper 1/3• FS fx –

– Ant table- cosmesis, sinus function– post table- sinus fxn, neurosurg

• Supraorbital rim comminuted fx FS recess injury• Centrally located + severe fx CSF leakMid 1/3Orbits

– Orbital apex syndrome- II, III, IV, V, VI– Superior orbital fissure syndrome- III, IV, V, VI– Blowout fx- rims intact w/ 1 or more walls fx, usu floor/medial

wallLe ForteNOE

Schemas

Le Forte ?- complete craniofacial separation- zygoma, through orbit, nasaofrontal jxn

Le Forte ?- horizontal max fx above dentition

Le Forte ?- pyramidal fx- orbital rims/floor, nasal root

Schemas

Le Forte I- horizontal max fx above dentition

Le Forte lI- pyramidal fx- orbital rims/floor, nasal root

Le Forte III- complete craniofacial separation- zygoma, through orbit, nasaofrontal jxn

Schemas• Type ? bone fragment

containing MCL freed from surrounding bone

• Type ? MCL tendon detached or attached to a fragment that is irreparable ie bilat orbital wall fx

• Type ? comminuted fx, repairable via transnasal fixation

Schemas• Type I bone fragment

containing MCL freed from surrounding bone

• Type II comminuted fx, repairable via transnasal fixation

• Type III MCL tendon detached or attached to a fragment that is irreparable ie bilat orbital wall fx

Management- access• Start ppx abx immedSurgical access- existing lac? Upper 1/3• Coronal incision, access to pericranial flap, beware frontal br and

supraorbital nMid 1/3• Zygoma- gilles, gingivobuccal• Lateral orbital rim- upper bleph, lateral brow, lower lid

transconjunctival +/- lateral canthotomy• Orbital floor- transconj pre v post septal, transcutaneous subciliary v

lower lid crease (frost stitch)• Medial orbit- transcaruncular, lynchLower 1/3• Mandible- intraoral, beware mental n, transcervical-

submand/submental incision, retromandib inci, beware mental n, facial n.

Biomechanics

Facial skeleton has areas of strength and weakness

Strength- buttresses/pillarsWeakness- crumple zones eg. LP/ethmoid

bones- direct blunt trauma to central face telescoping NOE fx, dissipates force protecting globes. Same concept for purpose of sinuses.

BiomechanicsUpper 1/3• frontal ant table- weak• supraorbital rim- strong, protects orbits and ant

cranial fossaMid 1/3• vertical buttress x4: nasofrontal/nasomax,

frontozygomatic/zygomaticomax, pterygoid• horizontal bars x4: frontal bar, zygoma, infraorbital

rim, palateLow 1/3• Mandible upper beam- tension forces• Lower beam- compressive forces

Fracture Repair- principlesPurpose of fx repair- regain aesthetic form and occlusal fxnRigid fix- elim movement across fx, allows primary bone

healing, minimizes callus formationOcclusion>>fracture reductionMMF, ivy loops, IMF- to re-est occlusionWork from stable to unstable, known to unknown, periphery

to centerRe-est facial height 1st -repair mandible 1st, make sure midface

not impacted/rotated before rigid fixationThen stabilize buttresses- L/J plates Then central face Then orbits- floor has irregular convexity, not a complete

sphere, failure to recognize will cause enopthalmos Repair CSF leaks immediately, longer leak incr r/o

meningits

Mandible fx repair2 schools

1) Champy- miniplates + monocortical screws2) Speisl- MMF + compressive plate w/ bicortical screws

Body- single miniplate +/- bicortical compression plateSymphysis- 2 miniplatesAngle- very complex/changing forces, recon plate v single 1.3mm miniplate v

2 2mm miniplates, highest rate complicationsRamus- 2 2mm miniplatesSubchondylar- MMF v open- risk to FN

indications for open- – chondylar displacement into MCF – inability to obtain reduction– lateral extracapsular displacement of chondyle– FB

Relative indications- – B chondylar fx + edentulous, + comminuted midface fx, +gnathologic problems– when splinting not recommended

Mandible fx repairLoad sharing- depends on integrity of bone, eg miniplate,

compression plate, lag screwLoad bearing- atrophic/thin/comminuted fx- repair needs to

bear load across the affect bone eg recon plate w/ 4 bicortical screws on each side. Fall-back technique for all repairs

Locking (v nonlocking) screws allows for less than perfect plate bending.

Other options:• ex fix, MMF 4-6 wks

Tooth in fx line-leave alone if: healthy, 3rd molar in angle fxremove if: infected, interferes w/ reduction

Frontal Sinus Fx

Anterior wall nondisplaced- obsAnterior wall displaced- repairAnterior wall + FSR injury- oblit v obsPosterior wall nondispl +/- FSR- obsPosterior wall displ- trephine + transcut endoscopy

(r/o herniated brain)

Obliteration- pack w/ fat, seal recess w/ cement or pericranial flap

Cranilization- removal of posterior table

NOE repair

Type I- stabilize the floating bone to surrounding bone w/ plate

Type II/III- stabilize MCL to the contralat frontal bone or MCL w/ permanent suture or wire

Complications

MalocclusionContinued movement across a fx leads to:• nonunion- persistent gap/fx• fibrous union/pseudoarthrosis- persistent callus

w/o bone formation• malunion- bone heals in wrong positionScarEntropion/extropionNerve injury