Di Imaging II - Exam 1 (Spine Trauma)

What is the most clinically significant Dx

cleidocranial dysplasia

What is the most significant finding

absent posterior arch of C1

What is the most clinically significant Dx

congenital absent posterior arch of C1

• know congenital b/c enlarged anterior tubercle (compensatory change)

What is the appropriate follow up imaging based on the previous dx

flexion/extension x-rays

What is the most significant finding

missing pedicle at L4

What is the most appropriate follow up based on the previous finding

compare to old x-ray films (congenital or pathologic?)

What is the most likely Dx

Ankylosing Spondylitis

• require HLA-B27 testing

What is the most likely Dx

Renal osteodystrophy or Hyperparathyroidism

• findings: endplate sclerosis/Rugger jersey spine

What is the normal maximum for RPI (retropharyngeal space) measurement

7mm

Concerning the most significant Dx, is this considered stable or unstable

Unstable

• Dx: Atlantoaxial instability

• Finding: Widened ADI

• Test: Flexion/Extension

Is this fracture stable/unstable and new/old?

stable + new

• doesn’t involve middle/posterior column

• line of impaction

What is the most likely etiology of this compression fracture

osteoporosis

What percentage of skull fractures are typically missed on x-rays

90%

What imaging is preferred to find a skull fracture

CT

What type of skull fracture is this

Depressed Skull Fx

What type of skull fracture is this

Depressed Skull Fx

What is this x-ray image of

Depressed Skull Fx w/large epidural hematoma

What is the name of the skull fracture that involves the orbits

Blowout Fracture

What type of skull fracture is this

Blowout Fx/Orbit Fx

What type of skull fracture involves the zygoma (elephant)

Tripod Fracture

What type of skull fracture is this

Tripod Fx/Zygomaticomaxillary complex Fx

What is the name of the skull fractures that involve the face (facial fx)

Le Fort Fracture

What type of hematoma is found on this x-ray

Epidural Hematoma

• btw skull and dura

• biconvex

• arterial involvement

What type of hematoma is found on this x-ray

Subdural hematoma

• crescent shaped

• btw dura and arachnoid

• venous involvement

What is the most common skull fracture

Linear Skull Fx

What is the most common MOT (mechanism of trauma) in the spine

hyperflexion

Hyperflexion injuries list

simple wedge (compression) fx

bilateral facet dislocation

flexion teardrop fx

clay shoveler’s fx

anterior subluxation/misalignment

dens fx

Hyperflexion and Rotation injuries list

unilateral facet dislocation

unilateral facet fx-dislocation

Hyperextension injuries list

avulsion of anterior tubercle of C1

hyperextension fx-dislocation

hyperextension dislocation

posterior arch fx of C1

extension teardrop fx

hangman’s fx

lamina fx

dens fx

Hyperextension-rotation injuries list

pillar fx

pedicolaminar fx

Vertical compression forces injuries list

jefferson’s fx of C1

bursting fx

Lateral flexion injuries list

unilateral fx of lateral masses C1

transverse process fx

uncinate process fx

Where are the MC locations of spinal trauma

C1-2

C5-7

T12-L1

Davis Series (7 view cervical spine series)

traumatic (24-48hrs) - expose, process, examine one film at a time

non-traumatic (>24-48hrs) - take all 7 images, then examine

What encompasses a Davis Series

Lateral Cervical

APOM

AP Cervicals

Obliques

Flexion/Extension

Swimmer’s

What is the name of the space btw the outer and inner table of the skull

Diploic space

What are the arrows pointing to on this image

calcification of stylohyoid ligament

What intersegmental motion should we see on a normal flexion film

anterior closes down

posterior opens

translation anterior slightly

What intersegmental motion should we see on a normal extension film

anterior opens

posterior closes down

translation posterior slightly

What is the finding at C4 on this film

hypermobile in extension (moved too far posterior)

What is the finding at C4-7 of this film

hypomobile in extension

What is the definition of Instability

gross ligamentous damage

with or without neurological insult

or the potential of neurological insult

3 Column Method

Unstable if…more than 1 column is disrupted OR middle column is disrupted

What are the three columns

anterior (anterior 2/3 VB)

middle (posterior 1/3 VB + PLL)

posterior

If a patient has a new fracture or an unstable fx, they require a

orthopedic cosult

Abnormal soft tissues can be seen at these four places

retropharyngeal space/RPI (C2)

retrotracheal space/RTI (C6)

pre-vertebral fat stripe

tracheal air shadow

What are the appropriate measurements for the RPI and RTI

RPI <7mm (or less than ½ width of adjacent VB)

RTI <22mm

If a patient was in a MVA, what should you think is causing the abnormal RPI or RTI

blood or edema

What is causing this 41yo post operative pt’s increased RPI and RTI

infection or edema

What type of weight bearing is this pt

anterior weight bearing

Decreased joint space and/or decreased disc height can be attributed to these things

joint disease (most common DDD + RA)

developmental

infection

What is the most likely cause of this pt’s increased RPI and RTI

infection (due to recent surgery)

What abnormal soft tissue is found on this x-ray

displaced pre-vertebral fat stripe

On a MRI, what color should the cortex of bone be

dark (low intensity)

On a CT, what color should the cortex of bone be

bright (high intensity)

What are three things that could cause anterior displacement of C1

C2 fx

dens fx

widened ADI

What is the finding at C4 and C5

C4 is anterior to C5 (dislocation) (yellow arrow)

interspinous widening (white arrow)

What line do we use to find a dislocation

George’s line (posterior vertebral line)

What are the findings of a Bilateral facet dislocation

widened interspinous space

anterior displacement

high riding facets (not articulating well)

decreased disc height

What are the normal measurements of ADI

Adult <3mm

Child <5mm

What is the dx in this film

atlantoaxial instability

Radiographic features of a severe sprain

interspinous widening

loss of parallelism btw facets

horizontal/sagittal displacement >3.5mm

angular/rotation displacement >11 deg

Interspinous widening is typically what type of injury

flexion injury

DDD allows for ___ translation vs DJD allows for ___ translation

DDD = posterior

DJD = anterior

Fracture healing

body heal w/fibrosis

arch heal w/callus

What is found on this image

atlantoaxial distraction (internal decapitation)

What is the MC fracture of C1 (atlas)

posterior arch fx

Posterior Arch Fracture characteristics

bilateral and vertical

MOI = hyperextension

DDx = focal agenesis

What are the three findings of this film

C1 posterior arch fx

prevertebral soft tissue swelling/edema

C2 avulsion fx

Can we say that this posterior arch fx is stable

Yes, unless they are neurologic - then it is unstable

What is the finding on this flim

unilateral posterior arch fx

What is the Dx

Absence/Agenesis of posterior arch of C1

• hypertrophic anterior tubercle + corticated margins = not fx

What two Dx are found on this film

posterior arch fx of C1

odontoid fx of C2

What is found on this film

anterior arch avulsion fx

What type of fracture is this at C1

Jefferson’s fx or Bursting fx of C1

Jefferson’s fracture characteristics

MOI = axial compression (head first dive)

bilateral fx of anterior and posterior arches

bilateral lateral mass offset

unstable if transverse ligament torn >7mm

How do you find out if a Jefferson’s fx is unstable

What is the finding and the dx of this image

finding = increased ADI

dx = atlantoaxial instability

What is the dx

unstable Jefferson’s fx

What is the dx

posterior arch fx

What is the finding and dx of this image

finding = bilateral lateral mass offset

dx = jefferson’s fx

A C1 fx is unstable if

ADI is increased OR have neurological symptoms

Atlantoaxial dislocations/instability are usually associated with _____ most commonly

RA

T/F: A widened ADI causing atlantoaxial instability is considered UNSTABLE and upper cervical adjusting is contraindicated

True

Etiologies of an increased ADI

trauma

Down’s syndrome

major upper cervical anomalies

inflammatory arthropathies

What seropositive and seronegative inflammatory arthopathies are MC going to cause an increased ADI

seropositive = RA

seronegative = AS

What major upper cervical anomalies require flexion/extension films

occipitalization

agenesis of posterior arch

os odontoidium

What is the best view to fully evaluate the ADI and integrity of the transverse ligament

cervical flexion

What finding is on this film besides a widened ADI

uncinate hypertrophy (pseudofracture)

Steele’s Rule of Thirds (divides ring of atlas/C1 into thirds)

1/3 cord

1/3 odontoid

1/3 potential space

Odontoid fractures (40-50% of C2 fx)

Type 1 = oblique/avulsion fx at tip

Type 2/High dens = fx at base (MC)

Type 3/Low dens = fx into body

Which type of dens fracture disrupts Harris’ ring

Type 3/Low dens

What type of dens fx is this

Type 1 (alar or apical ligament avulsion)

What type of dens fx is this

Type 2/High dens

What type of dens fx is this

Type 3/Low dens

Of the three types of dens fractures, which are stable/unstable

Type 1 = stable

Type 2/3 = unstable

What is this image of

Mach effect (overlying posterior arch)

• illusion of an odontoid fracture

What is the dx if this pt is <12 yo

Os terminale (ununited secondary ossification center)

Where is the lowest amount of trabeculae in the odontoid

at the base

Most os odontoideum are

old ununited dens fractures