Transcript Slide 1

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3% of MVA patients , have cervical spine
injury
10-20% patients with head injury, have
also cervical spine injury
Most cervical spine fractures occur at two
levels
17% of patients have a missed or delayed
diagnosis with a risk of perminant
neurologic damage
1/3 of injuries occur at level of C2 and ½
occur at level of C6-C7
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The NEXUS criteria state that a patient with
suspected cervical spine injury can be
cleared providing the following:
*- no posterior midline cervical spine tenderness
*- no evidence of intoxication is present
*- patient has a normal level of alertness
*- no focal neurologic deficit
Plain films
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3 views should be taken :
- true lateral view
( must include all 7 cervical
vertebrae as well as the C 7 – T1 junction )
- an AP view
- an open mouth (odontoid view)
The lateral view …
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The lateral view is the most useful view,
approximately 85-90 % of spinal injuries are
evident on this view
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Should be obtained & examed before any other
films are taken
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All 7 cervical vertebrae and the C7-T1 junction
must be visualized because the cervicothoracic
junction is a common place for traumatic injury
Is this an adequate lateral film?
AP & odontoid view
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If lateral view is normal, proceed with AP &
odontoid views
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Patient should be maintained in cervical
immobilization and plain films or CT scans
obtained untill all vertebrae are clearly
visible.
Anatomy
Lateral view
AP view
Odontoid view
Alignment
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Systematic
approach:
* check alignment by
following 3 contour
lines
- anterior contour line
- posterior contour line
- spinolaminar contour
line
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These lines should follow a slightly lordotic
curve, smooth and without step-offs.
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Any malalignment should be considered
evidence of ligamentous injury or occult
fracture and cervical spine immobilization
should be maintained untill a definitive
diagnosis is made.
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Alignment should be
AP
evaluated using the edges
of vertebral bodies and
articular pillars
Hight of vertebral bodies
should be equal
Hight of joint space should
be equal
Spinous process should be
in midline, if displaced to
one side , a facet
dislocation should be
suspected.
view
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The distance from the
dens to lateral
masses of C1 should
be equal bilaterally.
Any asymmetry is
suggestive of a
fracture of C1 or C2
Lateral mass of C1
should line up with
lateral margins of
suprior articular facet
of C2. if not, a
fracture of C1 is
suspected.
Odontoid view
Prevertebral space
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Nasopharyngeal space {C1}
-- 10 mm in adult
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Retropharyngeal space {C2-C4}
-- 5-7 mm
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Retrotracheal space {C5-C7}
-- 14mm in children
-- 22 mm in adults
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Prevertebral soft tissue swelling is
important as it is usually due to hematoma
2ry to occult fractures
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Soft tissue swelling in symptomatic patient
should be considered an indication for
further radiographic evaluation
CT
CT
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20% of fractures are missed on plain
radiographs
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Useful in fractures that result in
neurologic deficit and in fractures of
posterior elements
( e.g. Jefferson’s
fracture)
Advantages of CT
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Excellent in identifying osseous
compromise of the vertebral canal
Visualization of subtle fractures
Provides patient comfort by being able to
reconstruct images in axial , sagittal ,
coronal planes and 3D from one patient
position.
Soft tissue window & bone window
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****** limitations:
* unable to show ligamentous
injuries
* relatively high costs
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Excellent in
identifying
osseous
compromise of
the vertebral
canal
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Visualization of subtle
fractures
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Provides patient
comfort by being
able to reconstruct
images in axial ,
sagittal and
coronal planes
from one patient
position as well as
3-d reconstruction
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Soft tissue
window &
bone
window
MRI
MRI
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Advantages:
* excellent soft tissue contrast, making it the
study of choice for spinal cord survey ,
hematoma and ligamentous injuries.
* good general overview because of its ability to
show informations in different planes
* ability to demonstrate vertebral arteries which is
useful in evaluating fractures involving the
course of vertebral arteries
* no ionizing radiation
MRI
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Disadvantages
* loss of bony details
* high cost
- patients with pacemakers and certain
ferromagnetic materials ( aneurysm clips )
are not able to be scanned
MRI diagnostic values
Spinal cord lesions
Bone marrow pathology
Ligamentous injuries
soft tissue edema
MRI
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T1W – display anatomic details
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T2W – display pathologic changes better
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Together – enable detection &
characterization of most lesions
Stability
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Spinal stability is
depending on at
least two intact
columns.
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When two of the
three columns
are disrupted , it
will allow
abnormal
segmental
motion.
Spinal cord injury
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Two types:
* nonhemorrhagic:
only high signal on
T2W
* hemorrhagic:
areas of low
signals on T2W
within the area of
edema
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Hemorrhagic spinal cord injury has an extremely
poor outcome
Mechanism of injury
Hyperflexion
Hyperextension
Compression
Hyperflexion …….
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Excessive flexion of
neck in sagittal plane
Diving in shallow
water
Flexion tear drop
fracture
Hyperextension
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Excessive
extension of neck
in sagittal plane
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Hitting the dash
board in MVA
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Hangman’s
fracture
Axial compression
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Force applied directly
over the vertex in the
caudal direction
Jefferson fracture
Bursting fracture
Cervical spine injuries
Unstable fractures
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Hyperflexion :
- bilateral facet dislocation
- flexion tear drop fracture
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Hyperextension
- Hangman’s fracture
- hyperextension dislocation fracture
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Compression :
- Jefferson’s fracture
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Complex :
- odontoid fracture
- atlanto-axial dissociation
Hyperflexion unstable
injuries
•Bilateral
facet dislocation
•Flexion tear drop fracture .
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Normal relationship of
facet joints, inferior
articulating facet of
body above (blue
arrow) lies posterior
to superior facet of
body below (red
arrow).
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Body of C4 is
subluxed anteriorly on
C5. inferior facet of
C4 (blur arrow) lies
anterior to superior
facet of C5 (red
arrow).
Unilateral facet dislocation
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Due to
simultaneous
hyperflexion with
rotation
30% associated
with neurologic
defect
Radiographic
features:
 Lateral view :
- anterior dislocation
of affected vertebral
body by less than ½
of the vertebral AP
diameter.
- widening of
interspinous space
the superior facet on one side slides over the
inferior facet and become locked, the
contralateral facet joint is only distracted.
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AP view:
- malalignment of
spinous processes
which can only be
produced by a
rotatory injury.
the involved spinous
processes points to
the involved side
- due to the rotation,
the involved spinous
processes seem
shorter on the lateral
view
** MRI findings :
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Spinal cord lesions
Soft tissue swelling
Rupture of
interspinous ligament
and ligamentum
flavum
Rupture of the disc
Unilateral facet dislocation
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Flexion and rotation force
Limited antrolithesis less than 25%
Bilateral facet dislocation
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Results from
extreme
hyperflexion
Unstable
Associated with a
very high risk of
cord damage
***Radiographic features:
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Complete anterior
dislocation of affected
vertebral body by half
or more of its AP
diameter
Disruption of posterior
ligament complex and
anterior longitudinal
ligament
“ Bow-tie “ appearance
of the locked facets
Essentials for diagnosis
• Displacement of the upper vertebra by more
than 50% of the vertebra below
• The articular facets of the upper vertebra
becomes anterior to articular facets of the lower
vertebra
•Common association
C4/5
•Disc herniation
•Epidural hematoma
5
4
Bilateral facet dislocation
Hamburger sign
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UFD
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BFD
Flexion tear drop fracture
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Mechanism :
hyperflexion with
compression
( diving into
shallow water )
Unstable
70 % have
neurologic deficit
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Radiographic features
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Posterior vertebral body
subluxation into the
spinal canal
Teardrop fragment from
the anteroinferior aspect
of the vertebral body
Anterior longitudinal
ligament tear with
prevertebral swelling
Spinal cord
compression from
vertebral body
displacement
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Flexion teardrop fracture
Hyperextension
injuries
Hangman’s fracture
Hangman’s fracture
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Traumatic spondylolithesis
Mechanism : hanging , chin hits dashboard in
MVA
Unstable
Seldom is associated with spinal
cord injury , since the AP diameter
of the spinal canal is greatest at this
level and the fractured pedicles allow
decompression
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Radiographic features:
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Prevertebral soft tissue
swelling
Avulsion of anterior inferior
corner of C2 associated with
rupture of anterior longitudinal
ligament
Anterior dislocation of C2 body
Bilateral C2 pars
interarticularis fracture
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Hyperextension and
distraction
Fracture involves both
pars interarticularis of
C2
Compression fractures
Jefferson’s fracture
Jefferson fracture
Description : compression
fracture of C1
 Mechanism : diving injury
 Stability : unstable
 Radiographic features :
- AP open mouth : lateral
offset of lateral masses of
C1 beyond margins of
body of C2
- CT is required to define
the extent of fracture and
to detect fragments in
spinal canal
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Jefferson’s fracture……………………...
Complex fractures
Odontoid fracture
Atlanto-occipital dissociation
Odontoid fracture
Atlanto-occipital disassociation
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Description: disruption of atlanto-occipital
junction involving atlanto-occipital
articulation
Mechanism : hyperflexion or
hyperextension
Stability: unstable
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Radiographic
features:
Malposition of
occipital
condyles in
relation to
superior facets
of atals
Prevertebral
soft tissue
swelling
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Displacement of
atlanto –
occipital
articulation
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Prevertebral
soft tissue
swelling