AXIAL SKELETAL TRAUMA
INTRODUCTION
MSK TRAUMA INTRO.pdf
Surgeons care about 2 things: form and function
Does the fx cause a significant cosmetic deformity that requires repair (form)?
Does fx pattern cause injury to an adjacent anatomic structure that disrupts normal function and creates sx for the patient (function)?
Treating surgeons need to restore normal facial contour and thus need to know which key articulations and buttresses have been disrupted and need to be carefully realigned.
Buttress anatomy
Horizontal:
Upper transverse (orbital floor)
Lower transverse maxillary (palate)
Upper transverse mandibular
Lower transverse mandibular
Vertical:
Medial maxillary (medial orbital wall)
Lateral maxillary (lateral orbital wall)
Posterior maxillary (pterygomaxillary)
Posterior vertical
High impact fx: supraorbital rim, mandibular symphysis, frontoglabellar, mandibular angle.
Low impact fx: zygoma, nasal bones
MIDFACIAL FX PRINCIPLES OF REDUCTION AND COMPLICATIONS.pdfMaxillofacial midface fractures.pdfFRONTAL SINUS FX
Frontal sinus drainage pathway (inverted funnel shape) is bordered...
Anteriorly by agger nasi and frontal recess Kuhn cells
Posteriorly by bulla ethmoidalis, frontal bullar, suprabullar cell
Posteriorlaterally by supraorbital ethmoidal cells.
Management of frontal sinus fx depends on the displacement, comminution and sites involved including: thicker anterior table, thinner posterior table, frontal recess
Posterior table involvement (almost always also w anterior table) confers risk of CSF leak and intracranial infection.
Frontal recess disruption confers risk of frontal sinus mucocele/mucopyocele development.
ORBITAL FX
Traumatic deformity of orbital floor (MC) OR medial wall resulting from impact of blunt object larger than orbital aperture; pure w/o orbital rim fx; impure w/ orbital rim fx
2 broad categories:
Open door: large displaced frequently comminuted
Trapdoor: linear, hinged, minimally displaced
Associated findings
herniation of orbital contents
Involvement of infraorbital canal
Oribital ST injury
Orbital emphysema can have mass effect -> compression/stretch of optic nerve insertion w/ tenting of globe.
Can involve combo injury with nasal, LE fort, ZMC
Trapdoor fx: special type of floor blowout that usually occurs in children where the inferiorly displaced fx fragment recoils and entraps herniated orbital ST, which can cause restricted motility or necrosis of the inferior rectus mm.
Large orbital blowouts (>2 cm defect area or >1.5 mL outward herniated volume) predicts development of noticeable enophthalmos after acute swelling subsides.
Report:
Entrapment is a clinical diagnosis. Must note position, orientation and configuration of EOMs as functional entrapment can occur without significant displacement.
Check for mass effect on optic nerve insertion from retrobulbar hematoma or emphysema
NASO-ORBITO-ETHMOID FX (NOE)
Medial canthal tendon inserts on the medial orbital rim
Involves the upper central midface classically along 5 key edges:
Pyriform aperture across the lateral nasal wall
Inferior orbital rim and floor
Medial orbital wall
Frontomaxillary suture
Nasomaxillary suture
Classified based on morphology of central fragment:
Type 1: noncomminuted large central fragment
Type 2: comminuted central fragment not disrupting area of medial canthal tendon insertion
Type 3: comminuted central fragment disrupting area of medial canthal tendon insertion.
Report
Type of medial orbital rim fx and degree of surrounding comminution.
Distance b/n 2 lacrimal fossae in coronal plane
Involvement of frontal sinus drainage pathway and orbit
NASOSEPTAL FX
MC facial fx. isolated nasal fx should be distinguished from more serious NOE fx.
Lateral-oblique forces fx the bony nasal pyramid (nasal bones and/or frontal processes of maxillae). Frontal forces additionally involve the anterior nasal spine and/or cartilaginous or bony nasal septum.
Associated septal hematoma can cause necrosis of the cartilage and subsequent saddle nose deformity. Specifically evaluate for septal hematoma!
TRANSFACIAL / LE FORT FX
3 types, all of which involve the pterygomaxillary buttress (pterygoid plates) which results in detachment of the maxillary occlusion-bearing segment (palate, alveolus, and maxillary teeth) from the skull base (pterygomaxillary disjunction) and results in varying degrees of midface detachment depending on severity of injury.
Type 1: lateral margin of pyriform (nasal) aperture (inferior orbital rim and zygomatic arch intact) -> free movement of hard palate (floating palate)
Type 2: pyramidal fx involving the inferior orbital rim, orbital floor and medial orbital wall -> free movement of nose and hard palate (floating maxilla)
Type 3: zygomatic arch, lateral and medial orbital walls -> free movement of entire midface (craniofacial dissociation)
Non-occlusion related components of the upper level Le Fort fx can be treated as combinations of NOE, ZMC and/or orbital fx. However, must report at Le Fort 2 or 3 as detailed in Denver screening criteria for blunt cerebrovascular injury (need CTA H&N)
ZYGOMATICOMAXILLARY COMPLEX FX (ZMC)
Fx complex involving zygomatic arch, lateral orbital rim/wall, anterior & lateral maxillary sinus walls, and orbital floor. it is a spectrum of injuries and not all four components must be involved (incomplete ZMC).
2 major ZMC buttresses: upper transverse maxillary, lateral vertical maxillary
Weakest point of ZA is 1.5 cm post to zygomaticotemporal suture.
Incomplete ZMC fx may involve only one of the following: zygomatic arch, lateral orbital rim/wall, or inferior orbital rim.
The zygmaticosphenoid suture is a sensitive landmark for evaluating overall ZMC alignment: displacement, angulation, telescoping)
Displacement or malalignment of ZMC fx can disrupt facial profile and width.
MANDIBULAR FX
2nd MC facial fx and can lead to malocclusion. Fx typically linear or branching.
Fx are described by the involved anatomic segments involved:
Condylar process -> further subdivided head, neck, and/or base
Coronoid process
Ramus and angle
Body (3rd molar to canine)
Parasymphysis/symphysis
Mandible simulates a bony ring, thus multiple breaks are common:
Parasymphyseal fx on 1 side often associated w contralateral angle/body or subcondylar fx
B/l subcondylar fx after direct impact to symphysis.
Unilateral mandibular fx can occur w contralateral TMJ dislocation.
Guardsman fx: parasymphyseal and b/l condylar fx
B/l parasymphyseal or body fx w posterior displacement of central fragment and tongue -> airway compromise! Emergency!
Fx that extend to periodontal ligament space of an erupted tooth should be especially noted as they are managed as open (contaminated) fractures.
Displaced or complex mandibular fx, especially those involving the condyles, are associated w increased risk of blunt vascular injury and warrant a neck CTA.
DENTOALVEOLAR TRAUMA
TOOTH EMERGENCY.pdf
Tooth fx are classified by what is involved: crown, root, or both.
Crown fx are categorized by involved layers: enamel-only, enamel-dentin, or enamel-dentin-pulp
Partial axial displacement of a tooth may be...
directed out of its socket = extrusive luxation (loosening)
directed into its socket = intrusive luxation
Avulsion = complete displacement out of the socket.
Alveolar process fx: can spare or involve the socket and allow eccentric displacement of a tooth from its socket, which is called lateral luxation.
Nondisplaced tooth fx can be seen as a linear area of low attenuation traversing the tooth.
Tooth avulsion or luxation can be associated w socket fx and seen as widening of the periodontal ligament space; most commonly affects the central incisors in children 7-14 yo. Early dx while the periodontal ligament cells are still viable allow for early tooth reimplantation.
