Cervical Spine Flashcards
What are the 3 standard views of the cervical spine?
- Anteroposterior (AP)
- APOM
- Lateral views
What projection is necessary to assess the lower cervical segments and the cervicothoracic junction?
Swimmer’s lateral projection
What projection is necessary to assess the neural foramina?
Bilateral oblique projections
What projections can assess instability?
Flexion-extension lateral views
Which diagnostic imaging technique is most sensitive to detecting subtle injuries and better at visualizing craniovertebral and cervicaotheroacic junctions?
CT
Which diagnostic imaging technique is recommended for any patient with neurological deficit? Why?
MRI, because of its ability to demonstrate position of bony fragments as well as injury to spinal cord, disk, and soft tissues
What are the 3 significant injury types in which radiographic examination is not necessary?
fracture, dislocation, or instability
What are the 2 evidence-based guidelines established to help the clinician decide if a patient has the potential for a significant c-spine injury and if radiographic examination is necessary or not?
- Canadian C-Spine Rule (CCR)
- National Emergency X-Radiography Utilization Study (NEXUS)
The Canadian C-Spine Rule (CCR) applies to what type of patient?
Those who are alert and medically stable
What is the Canadian c-spine rule designed to decide?
whether conventional radiography of the cervical spine is necessary for patients who have sustained a traumatic injury involving the head or neck
What are the 3 questions that are asked during the Canadian C-spine Rule?
1) Are there any high-risk factors that mandate radiography?
2) Are there any low-risk factors that allow safe assessment of ROM?
3) Is patient able to rotate neck actively at least 45° to right and left?
What are 3 examples of high-risk factors that mandate radiography?
- age greater than 65
- dangerous MOI
- numbness of tingling in the extremities
What are the 4 low-risk factors that allow safe assessment of ROM?
- simple rear-end motor vehicle accident
- normal sitting position
- patient being ambulatory at any time
- delayed onset of neck pain
- absence of midline cervical spine tenderness
If the answer to one of the low-risk factors is no, what is the next step?
obtain radiographs
If the answer to one of the low-risk factors is yes, what is the next step?
move to question #3
If the patient is unable to rotate their neck actively at least 45° to right and left what is the next step?
obtain radiographs
The CCR has a sensitivity of __% and a specificity of __%
100%
43%
A test with high sensitivity is good at ruling ____ a disorder if the test is negative.
out
A test with high specificity is good at ruling ____ a disorder if the test is positive.
in
Define sensitivity
A test’s ability to obtain a positive test when the target condition is really present
***true positive
Define specificity
A test’s ability to obtain a negative test when the condition is really absent
***true negative
What is the NEXUS designed to do?
Determine whether or not patients need diagnostic imaging for c-spine based on their clinical presentation following trauma.
What are the 5 low-risk criteria in which, according to the NEXUS, if the patient does not exhibit will not need radiography?
- No posterior midline cervical tenderness
- No evidence of intoxication
- Normal level of alertness and consciousness
- No focal neurological deficit
- No painful distracting injuries
The NEXUS has a sensitivity of __% and a specificity of __%
- 6
12. 9
In summary, what are the 5 circumstances in which patients who have sustained acute trauma should have radiography?
- Dangerous MOI (diving accident, fall from height, motor vehicle accident)
- greater than 65 years of age
- Paresthesias in extremities
- Midline tenderness over spine
- Unable to rotate neck 45° to left and right
If a patient meets the clinical criteria of the CCR or NEXUS guidelines, what type of imaging should be performed?
CT with sagittal and coronal reformatting
OR
both CT and MRI as complementary studies to assess instability or myelopathy
What view should be the first radiograph evaluated if patient has a history of trauma and is not being evaluated in a trauma center? Why?
Lateral, because it allows for the assessment of normal cervical alignment with series of parallel vertebral lines
What view should be evaluated in severe trauma cases? Why?
A cross-table lateral view, because it is performed in supine, with the patient immobilized
What are the lateral flexion/extension stress views used to expose?
excessive segmental motion during functional movement
What are 3 abnormal soft tissue signs in the cervical spine?
- Widened retropharyngeal or retrotracheal spaces
- Displacement of trachea or larynx
- Displacement of prevertebral fat pad
There should be _ mm of space between C2 and the prevertebral soft tissue shadow
6
There should be _ mm of space between C6 and the prevertebral soft tissue shadow
22
What are 4 abnormal vertebral alignment signs in the cervical spine?
- Loss of parallelism as outlined for lateral view
- Loss of lordosis
- Acute kyphotic angulation with widened interspinous space
- Rotation of vertebral body
What does a loss of parallelism as outlined for lateral view, indicate?
fracture, dislocation, or severe degenerative changes
What does a loss of lordosis indicate?
muscle spasm in response to underlying injury
What does acute kyphotic angulation with widened interspinous space indicate?
rupture of posterior ligaments
What does rotation of a vertebral body indicate?
unilateral facet dislocation, hyperextension fracture, muscle spasm, or disk/capsular injury
What are 5 abnormal vertebral joint signs in the cervical spine?
- Widened ADI
- Widened interspinous process space (known as “fanning”)
- Widened IVD space
- Narrowed IVD space
- Loss of facet joint articulation
What does a widened ADI indicate?
degeneration, stretching, or rupture of the transverse ligament
What does a widening of interspinous processes indicate?
rupture of interspinous and other posterior ligaments
What does a widening of the IVD space indicate?
posterior ligament rupture
What does a narrowing of the IVD space indicate?
rupture of disk and extrusion of nuclear material
What does a loss of facet joint articulation indicate?
dislocation
Describe the difference between stable and unstable injuries
- Stable injuries are protected from significant bone or joint displacement by intact posterior spinal ligaments
- Unstable injuries show significant displacement initially or have potential to become displaced with movement
What are some examples of stable injuries?
- compression fractures
- traumatic disk herniations
- unilateral facet dislocations
What are some examples of unstable injuries?
- fracture dislocations
- bilateral facet dislocations
Which levels of the cervical spine are most frequently injured?
C1–C2 and C6–C7
Adults characteristically injure their ____ c-spine and children more frequently injure their ____ c-spine
lower
upper
Cervical spine fractures are associated with what 40% of the time?
neurological injury
What percentage of all spinal cord injuries occur in the c-spine?
⅔
What does SCIWORA stand for and what is it?
Spinal Cord Injury Without Radiographic Abnormalities
It is a type of spinal cord injury that occurs without fracture or dislocation
What type of patient is SCIWORA syndrome most common? Why?
Children, because of the inherent elasticity in the pediatric spine
What are the 2 classifications of fracture MOIs?
direct force or indirect force
Describe the difference between direct and indirect fracture MOIs
- direct force, such as blow to head
- indirect force, such as rapid acceleration/deceleration in motor vehicle accident
What are the 2 fracture configurations seen in c-spine?
- avulsion fractures
- compression/impaction fractures
What causes an avulsion fracture?
A bone fragment is pulled off by violent muscle contraction or by passive resistance of a ligament applied against an oppositely directed force
What causes a compression/impaction fracture?
adjacent vertebrae are forced together
What does a flexion force fracture produce?
The impacted vertebral body is compressed into an anterior wedge shape
What does a extension force fracture produce?
Compression of the articular pillars
What are the 6 types of fractures found in C3-C7?
- Wedge
- Burst
- Teardrop
- Articular Pillar
- Clay Shoveler’s
- Transverse Process
When does a wedge fracture occur?
Occurs when an interposed vertebra is compressed anteriorly by two adjacent vertebrae
What causes a wedge fracture?
hyperflexion forces
⅔ of wedge fractures in the cervical spine occur at what 3 spinal levels?
C5, C6, or C7
Are wedge fractures stable or unstable? Explain…
They may be stable because the surrounding ligamentous structures are at least partially intact
When does a burst fracture occur?
When an IVD is axially compressed and the nucleus pulposus is driven through an adjacent vertebral endplate, causing a literal bursting apart of the vertebral body and resulting in comminution
Are burst fractures stable or unstable? Explain…
They may be stable or unstable, depending on fracture configuration
When does a teardrop fracture occur?
Occurs when a triangular fragment of bone becomes separated from the anteroinferior corner of the vertebral body
A teardrop fracture results from either an avulsion force sustained during hyper_____ or compressive force sustained during hyper____.
extension
flexion
What type of teardrop fracture is the most severe of lower cervical fractures?
flexion
What are the other injuries associated with teardrop fractures?
IVD tearing, ligament rupture, and facet dislocation
Are teardrop fractures stable or unstable? Explain…
unstable, because of the damage to the ligaments, IVDs and dislocation of the facets
If the vertebral body is posteriorly displaced in a teardrop fracture, what can occur?
anterior cord compression resulting in quadraplegia
How does an articular pillar fracture occur?
Occurs when the spine is forced into compressive hyperextension combined with a degree of lateral flexion
Articular pillar fractures typically occur at C_.
C6
Are articular pillar fractures stable or unstable?
stable
What is a Clay shoveler’s fracture?
It is an avulsion fracture of a spinous process produced by hyperflexion forces or forceful muscular contraction of the trapezius/rhomboids
What is a Clay shoveler’s fracture often associated with?
Repetitive heavy labor of the upper extremities (as seen in shoveling)
Clay shoveler’s fractures typically occur at what spinal levels?
C6, C7, and T1
Are Clay shoveler’s fractures stable or unstable?
stable
Where do transverse process fractures typically occur?
C7, the largest transverse process in the c-spine
Transverse process fractures typically result from what?
lateral flexion forces, which cause an avulsion at the tip of the contralateral TVP
When can flexion and extension stress views be obtained?
When the patient does not have neurological complaints, they are willing, cooperative, and fully conscious
How are stable fractures treated?
immobilization
How are unstable fractures treated?
tong traction to decompress canal indirectly
Cervical dislocations are described by the direction in which the ____ vertebrae moves
superior
For example: an anterior dislocation of C2–C3 indicates that C2 is displaced anteriorly on C3
What are the most serious and life-threatening injuries to the cervical spine?
fracture–dislocations
What causes a fracture-dislocation of the atlantoaxial joint?
fracture through the base of the dens combined with ligament rupture
What is a hangman’s fracture associated with?
anterior dislocation of C2 on C3
Fractures of posterior vertebral structures combined with tears of posterior ligaments may cause the vertebral body to displace anteriorly, which can result in what?
transecting of the spinal cord
Dislocations that are not associated with fractures may be either complete or self-reducing and in reference to what?
facet joints
What are self-reducing dislocations?
Dislocations in which a force momentarily disengages articulations, which then return to normal alignment once force dissipates
aka subluxations
Complete facet joint dislocation may occur unilaterally at a segment as a result of what type of force?
flexion-rotation
Complete facet joint dislocation may occur bilaterally at a segment as a result of what type of force?
hyperflexion
When there is complete facet joint dislocation, there are “locked” facets, what does this mean?
The inferior articulating process of the uppermost vertebra will lie in front of the superior articulating process of subjacent vertebra, locking the joint out of normal articulation
What structures do unilateral facet dislocations damage?
one facet capsule and the posterior ligaments
Are bilateral facet dislocations stable or unstable?
stable
Are unilateral facet dislocations stable or unstable? Why?
Unstable, because there is extensive disruption of posterior ligaments, facet joint capsules, annulus fibrosus and sometimes the anterior longitudinal ligament
What are bilateral facet dislocations typically associated with?
spinal cord injuries
When does atlantoaxial rotary subluxation occur?
When forces of flexion or extension are combine with rotation to cause one of the inferior facets of C1 to slip anterior to superior facet of C2 and become fixed in this position
What do patients with an atlantoaxial rotary subluxation present with?
marked limitation of motion especially towards the subluxed side
What does the APOM view of an atlantoaxial rotary subluxation demonstrate?
asymmetry of joint space between the dens and lateral masses of the atlas
What do the lateral radiographs of an atlantoaxial rotary subluxation demonstrate?
The inferior facet of C1 positioned anterior to superior facet of C2
How are atlantoaxial rotary subluxations treated?
- Reduction via the use of traction techniques supplemented by active ROM exercises to restore alignment
- Immobilization with a cervical orthosis for several weeks following reduction
What is the clue to C3-C7 facet dislocation?
There is anterior displacement of the vertebral body which causes a misalignment of the posterior vertebral body line
Unilateral facet dislocation can result in forward displacement of about how much of the AP diameter of disk space?
up to 25%
Bilateral facet dislocation can result in forward displacement of about how much of the AP diameter of disk space?
at least 50%
What does the AP view of facet dislocations in the lower c-spine demonstrate?
- wide interspinous space at one level
- an abnormally wide IVD space
- deviation in spinous process alignment
Cervical sprains are injuries to _____ of spine
ligaments
Tears of the posterior ligaments allow for what?
The superior vertebra to rotate or translate anteriorly on its subjacent vertebra
Posterior ligament damage results in _____ angulation on the lateral radiograph
hyperkyphotic (loss of lordotic curve)
Do lateral radiographs reveal signs of joint instability associated with hyperflexion sprains (PLL tears)?
No, lateral flexion and extension stress films should be obtained
When do hyperextension injuries occur?
During isolated hyperextension or in rebound following hyperflexion
Hyperextension sprains disrupt ____ ligaments, which results in _____ subluxation
anterior
posterior
What does the lateral view of hyperextension sprains demonstrate?
vertebral misalignment secondary to ligamentous or IVD disruption
Are disk herniations resulting in nerve root compression common in the cervical spine? Why or why not?
No, because there is quite a bit of protection: anteriorly positioned NP, posteriorly reinforced AF, wide and double-layered PLL, and uncovertebral joints offer security to disks
Traumatic injury to the cervical spine may cause disc herniation in what directions?
posterior or lateral
What types of imaging techniques are useful in determining IVD herniations?
- Myelography
- CT myelography
- MRI
What are the 6 types of degenerative diseases that occur in the c-spine?
- degenerative disk disease (DDD)
- degenerative joint disease (DJD)
- foraminal encroachment
- spondylosis
- spondylosis deformans
- diffuse idiopathic skeletal hyperostosis (DISH)
What is degenerative disk disease (DDD)?
a disease in which the IVDs degenerate
DDD is most commonly seen in patients older than __ years of age
60
What is the result of DDD?
There is a decrease in disc height which results in excessive friction, which leads to osteophyte formation at articulation site and eventually around the entire osseous margin of endplates
What are 2 other characteristics of DDD?
- Schmorl’s nodes
- vacuum phenomenon
What are Schmorl’s nodes?
They are intravertebral herniations of NP through the endplate into spongiosa of the vertebral body
What is the vacuum phenomenon?
Accumulation of nitrogen gas in degenerative dehydrated fissures of disk
Why does DJD occur?
The articular facets undergo articular cartilage thinning, subchondral bone sclerosis, eburnation, and development of osteophytes at joint margins
What is foraminal encroachment the result of?
degenerative changes in adjacent structures (including DDD and DJD) that diminish the size of the IVF
What view permits assessment of the IVF?
oblique
What is foraminal encroachment seen as on the radiograph?
narrowing of the radiolucent ovals that represent the IVF
What is cervical spine spondylosis?
The formation of osteophytes in response to DDD
Where is osteophyte formation most predominant and why?
At points in the curvatures of spine farthest from center of gravity line, or at apices of concavities, as result of greater segmental mobility
C4–C5 and C5–C6
What is spondylosis deformans?
A degenerative condition characterized by anterior and lateral vertebral endplate osteophytosis that results from anterior or anterolateral disk herniation
Is disk height decreased in spondylosis deformans?
No
What is Diffuse Idiopathic Skeletal Hyperostosis (DISH)?
An etiology associated with diabetes, growth hormone, vitamin A or retinoid derivatives, and metabolic syndromes in which there is excessive osteophyte formation
What type of patients typically develop DISH?
Men around the age of 40
Where does DISH typically develop?
- middle to lower thoracic spine
- upper lumbar spine
- lower cervical spine
What 3 criteria distinguish DISH from spondylosis deformans?
- Flowing ossification along anterolateral aspects of at least four contiguous vertebral bodies
- Relative preservation of disk height and absence of radiographic evidence of DDD
- Absence of facet joint DJD or sacroiliitis
