(1,3) Cervical Spine Dislocation & Whiplash

Question 1

What are the 2 types of cervical spine dislocation?

Answer 1

• unilateral facet dislocation
• bilateral facet dislocation

Question 2

What is the mechanism of a unilateral facet dislocation?

Answer 2

flexion with rotation
(pulls facet forward on opposite side)

Question 3

What is the mechanism of a bilateral facet dislocation?

Answer 3

hyperflexion

Question 4

What is the stability of a unilateral facet dislocation?

Answer 4

stable until reduced
(therefore treat as unstable)

Question 5

What is the stability of a bilateral facet dislocation?

Answer 5

unstable

Question 6

What structures are damaged with a unilateral facet dislocation?

Answer 6

• ruptured interspinous ligaments
• ruptured facet capsular ligaments
• sprained PLL
• articular process Fx common
  (requires fusion post-reduction)

Question 7

What are the radiographic findings of a unilateral facet dislocation?

Answer 7

Lat:
- bowtie sign
- <25% anterolisthesis
AP: focal rotation

Question 8

What sign of unilateral facet dislocation is seen only on an axial CT?

Answer 8

hamburger sign

Question 9

What is the clinical significance of a unilateral facet dislocation?

Answer 9

neurologic deficit in 25% of pts

Question 10

What 3 forms of facet dislocation can occur with a flexion and rotation mechanism?

Answer 10

Unilateral:
- partial dislocation
- perched facets
- complete dislocation
(lecture only)

Question 11

What is a perched facet joint?

Answer 11

vertebral facet joint whose inf articular process appears to sit ‘perched’ on ipsi sup articular process of the vertebra below

Question 12

What structures are damaged with a bilateral facet dislocation?

Answer 12

• interspinous lig
• lig flavum
• facet capsules
• PLL
• 50% have disc herniation

Question 13

What are the radiographic findings of a bilateral facet dislocation?

Answer 13

• 50%+ anterolisthesis
• widened interspinous space
• NO bowtie sign

Question 14

What is the clinical significance of a bilateral facet dislocation?

Answer 14

neurologic deficit in 75% of pts
(greater reduction in spinal canal space)

Question 15

How would the spinal cord appear on a T2 MRI in the area of a bilateral facet dislocation?

Answer 15

cord = bright d/t hemorrhage

Question 16

What is whiplash associated disorder?

Answer 16

cervical sprain-strain injury

Question 17

What are the possible mechanisms for whiplash associated disorder?

Answer 17

• 20-60% of MVAs
• hyperextension-hyperflexion
• acceleration-deceleration

Question 18

What is the name of the classification system for whiplash associated disorder (WAD)?

Answer 18

Quebec task force on WAD

Question 19

What is a grade 0 WAD?

Answer 19

no complaints, no physical signs

Question 20

What is a grade 1 WAD?

Answer 20

neck pain/stiffness/tenderness only, no physical signs

Question 21

What is a grade 2 WAD?

Answer 21

neck complaint + MSK signs

Question 22

What is a grade 3 WAD?

Answer 22

neck complaint + neurologic signs

Question 23

What is a grade 4 WAD?

Answer 23

neck complaint + fracture or dislocation

Question 24

What are the common presentations of Whiplash?

Answer 24

• often asymptomatic
• muscle inj

Question 25

What are the less common presentations of whiplash?

Answer 25

- disc inj - ligament inj - neuro inj - dislocation - Fx - brain inj

Question 26

What are the radiographic findings of whiplash?

Answer 26

- prevertebral soft tissue abnormalities - abnormal vertebral alignment - abnormal discs (**CANNOT BE Dx ON ANY IMAGING**)

Question 27

When does maximum tenderness typically occur in patients with whiplash?

Answer 27

3 days post-inj, once cortisol and swelling go down

Question 28

What abnormal soft tissue findings of whiplash can be seen radiographically?

Answer 28

- widened prevertebral soft tissues - soft tissue emphysema (tracheal & laryngeal injury)

Question 29

What abnormal soft tissue findings of whiplash are *not* visible radiographically?

Answer 29

- brain inj (contusion, hemorrhage, concussion) - cord contusion & hemorrhage - muscle inj

Question 30

What clinical signs of laryngeal injury may be seen in a patient with whiplash?

Answer 30

- dysphagia - hoarseness

Question 31

What pre-existing factor would make whiplash injuries heal slower?

Answer 31

pre-existing degenerative change leading to cord contusion and hemorrhage

Question 32

What radiographic signs of abnormal vertebral alignment may be seen in a patient with whiplash?

Answer 32

- loss of lordosis - acute kyphotic angulation - widened interspinous space - altered flexion patterns

Question 33

What **static** imaging findings would **suggest** instability in a whiplash patient?

Answer 33

- localized acute kyphosis - interspinous widening >2mm indicative; >1.5x definitive) - facet gapping

Question 34

What **dynamic** imaging findings would **confirm** instability in a whiplash patient?

Answer 34

- translational instability on flex/ext views (3.5mm translation) - angular instability (11+ degrees angular motion compared to adjacent segments)

Question 35

What are the minimal diagnostic series for cervical spine radiographs?

Answer 35

AP lateral APOM

Question 36

What additional views may be obtained only after standard views have ruled out cervical spine fracture or dislocation?

Answer 36

bilateral obliques flexion/extension laterals

Question 37

What are 3 radiographic signs of abnormal discs in a patient with WAD?

Answer 37

- acute disc widening - annular vacuum clefts (trauma/degenerative) - vacuum phenomenon (degenerative only)

Question 38

What is the clinical significance of acute disc widening?

Answer 38

- alarm finding - significant disc inj - severe ligament disruption

Question 39

What are annular vacuum clefts?

Answer 39

traumatic avulsion of the annulus d/t hyperflexion or hyperextension inj, which may represent instability

Question 40

What is vacuum phenomenon?

Answer 40

degenerative finding involving the nucleus, appears as dark line (gas formation) in middle of nucleus

Question 41

What is the diagnosis and what are the radiographic findings?

Answer 41

Unilateral facet dislocation - bow tie sign - ~25% Anterolisthesis

Question 42

What is the diagnosis and what are the radiographic findings?

Answer 42

- 50%+ anterolisthesis - NO bow tie sign - widened interspinous space