SPINAL TRAUMA IMAGING

1. Spinal trauma
Dr. M Sanal kumar
Radiology resident

2. Spinal fractures and spinal cord injuries result mostly from
automobile accidents and sports activities.
Approximately 20% of spinal fractures are associated with
fractures elsewhere.
 Spinal cord injuries occur in 10–14% of spinal fractures and
dislocations.
Neurological damage is seen in approx. 40% of cases in
cervical spine , 10% of cases in thoracic spine and 4% in
thoracolumbar junction.

3. The incidence of neurological deficit is much higher when
fractures affect the neural arch as well as vertebral body.
10% of spinal cord injuries has no associated fractures.
Flexion is the most common line of force in spinal
injuries, with extension, rotation, shearing, compression,
and distraction occurring less frequently.
Fractures of the spinal column are found most commonly
at C1–C2, C5–C7, and T12–L2 levels.

4. Cervical Spine

5. Interpretation of Plain Film
• Mnemonic AABCS
• Adequacy
• Alignment
• Adequacy
• Bones
• Cartilage
• Soft tissue

6. Alignment

7. Anatomic Classification
3 Column Theory
Denis 83
Anterior- ALL ,Anterior annulus
fibrosus, Anterior 2/3 body
Middle - Post erior 1/3 body, Posterior
annulus fibrosus, PLL
Posterior- all structures posterior to PLL
AnteriorMiddlePosterior

9. Interpreting Plain Film
• Adequacy
– Should see C7-T1
junction
– If not get swimmer’s
view or CT

10. Bones

11. Cartilage
• Predental Space should be
no more than 3 mm in
adults and 5 mm in children
• Increased distance may
indicate fracture of odontoid
or transverse ligament injury

12. Cartilage Cont.
• Disc Spaces
– Should be uniform
• Assess spaces between
the spinous processes

13. Soft tissue
• Nasopharyngeal space (C1) -
10 mm (adult)
• Retropharyngeal space
• (C2-C4) - 5-7 mm
• Retrotracheal space (C5-C7) -
-14 mm (children)
- 22 mm (adults)
• Extremely variable and
nonspecific

14. AP C-spine films
• Spinous processes should line
up.
• Disc space should be uniform
• Vertebral body height should
be uniform.

15. Odontoid view
• Adequacy: all sses of
C1 and C2
• Bone: Inspect dens
for lucent fracture
lines

16. Stable or Unstable ??
Stability of cervical spine is provided by two functional
vertical columns
Anterior column: vertebral bodies, the disc spaces, the anterior
and posterior longitudinal ligaments and annulus fibrosus
Posterior column: pedicles, facets and apophyseal joints, laminar
spinous processes and the posterior ligament complex .
As long as one column is intact the injury is stable.

17. Mechanisms
of
Injury

18. Flexion injuries

19. Extension injuries

20. Axial compression injuries
Burst fracture at lower cervical level

21. Jefferson Fracture
Fractures of the Atlas
A bursting fracture of the ring of the atlas, with fractures
through the anterior and posterior arches.
It is a compression injury created by a forceful blow on
the skull vertex, which is transmitted through the occipital
condyles to the lateral masses of the atlas.
Majority occur from RTAs or diving injuries, usually into
too-shallow water.

22. The axial forces transmitted symmetrically through the occipital
condyles onto lateral masses of atlas drive the lateral masses outward,
resulting in bilateral, symmetrical fractures of the anterior and
posterior arches of C-1, which are invariably associated with disruption
of the transverse ligaments.

23. The radiographic signs can be subtle and require an adequate
AP open-mouth radiograph supplemented by CT.
The key signs are spreading apart of the lateral masses, creating an
increased lateral paraodontoid space bilaterally and offset of lateral
edge of atlas lateral masses and the axis superior articular processes.
 A total offset of > 8 mm signifies transverse ligament is also
ruptured.
Most lesions are bilateral, except when the causative force is
eccentrically applied to the skull and is transmitted in greater
magnitude to one lateral mass.

25. Posterior Arch Fracture of the Atlas
The most common fracture of the atlas , ~ 50% of all atlas fractures.
Usually a bilateral vertical fracture through the neural arch, through
or close to the junction of the arch to the posterior surfaces of the
lateral masses.
Mechanism
Fracture occurs as a result of the posterior arch of the atlas being
compressed between the occiput and the large posterior arch of the
axis during severe hyperextension.

26. Serious complications are unusual, though associated cervical
fractures may precipitate spinal cord injury.
Close anatomic proximity of the vertebral artery to the fracture site
may occasionally lead to serious vascular injury.

27. Anterior Arch Fracture of the Atlas
Fractures of the anterior arch of the atlas are usually horizontal
segmental avulsions from hyperextension at the attachment of the
anterior longitudinal ligament and longus colli muscle.
They constitute < 2% of neck fractures and often co-exist with
odontoid fractures.

28. Lateral mass fracture - rare and seen only with CT

29. Transverse Ligament Rupture
• Traumatic, usually associated with fractures.
• Also associated with inflammatory arhthritides (RA, AS);
Down’s syndrome (20%)
• Radiological signs are increased ADI (>3mm adult,
>5mm children) with disruption of spinolaminar line
• Steele’s rule of thirds- atlas ring is 1/3 cord, 1/3 space,
1/3 dens

32. Hangman’s Fracture
(Traumatic spondylolisthesis of C-2)
40% of all axis fractures.
The fracture occurs as a bilateral disruption through the pedicles of
the axis, usually in association with anterior displacement of C2 on C3.
It is common in automobile accidents, when the face strikes the
windshield before the vertex of the head, forcing the neck into
hyperextension.
Prevertebral hemorrhage is common, increasing the retropharyngeal
interspace that may compromise the adjacent airway.

33. Type II fracture associated
with a C2-3 facet
dislocation.
Fracture through the
pedicle of C2 extending
between the superior &
inferior facets
Type I fracture with
concomitant disruption
of intervertebral disk
C2-3.

34. There is a surprising lack of neurological findings in fractures of the
neural arch of the axis owing to the large spinal canal at this level.

36. Odontoid Process Fracture
Fractures of the odontoid process are common traumatic injuries
of the cervical spine, making up 40–50% of axis fractures.
Up to 30% of odontoid fractures will be associated with other
cervical fractures.
Mechanism is usually hyperextension.
 Pathologic fracture may complicate metastatic carcinoma,
multiple myeloma and other tumors, rheumatoid arthritis, and
ankylosing spondylitis.

37. Anderson and D’Alonzo
classification
Type I-Tip of the odontoid
process as a result of apical or
alar ligament stress.
Type II- Fracture at the junction
of the odontoid process and the
body of the axis.MC type.
Type III- Fracture through body of
C2 below base of dens
Stable (union)
Unstable (non-union)
Stable (union)

38. Type 1
Type 2
Type 3

40. GUILLOTINE EFFECT OF ANTERIOR ATLAS DISPLACEMENT
Odontoid process fractures result in less compression of the spinal
cord because the odontoid process and atlas move as a unit.

41. Pitfalls

43. Vertebral Body Compression Fractures
Wedge Fracture
Occurs as a result of mechanical compression of the involved
vertebra between adjacent vertebral bodies from forced hyperflexion.
 This is a stable fracture because the intervertebral disc, anterior
longitudinal ligament, and posterior ligamentous structures are intact.
Two thirds of wedge fractures occur at the C5, C6, and C7 segments.

44. The lateral radiograph is diagnostic, demonstrating a sharp,
triangular, anterior wedging of the superior vertebral endplate.
If the anterior height of a vertebral body measures at least 3 mm less
than posterior height, a fracture of vertebral body can be assumed.
An increase in the retropharyngeal interspace (RPI) above the normal
limit of 20 mm can occur as the result of prevertebral hemorrhage.

45. The mechanism of this fracture is identical to that of Jefferson
fractures involving C-1, but burst fractures are usually seen in the
lower cervical vertebrae (C3-7).
Nucleus pulposus, which is normally contained within the
intervertebral disk, is driven through the fractured vertebral end
plate into the vertebral body, the body explodes from within,
resulting in a comminuted fracture.
Burst Fracture

46. The posterior fragment is posteriorly displaced and may cause injury to
the spinal cord.
If the posterior ligament complex is not disrupted, a burst fracture is
stable & with ligamentous disruption, a burst fracture becomes
unstable.
There is increased interpedicular distance and a vertical fracture line of
the vertebral body.
 In the lateral view, the vertebral body is compressed to a variable
degree and the posterior cortical line is convex instead of concave.
CT is essential to assess the spinal canal and fragment position

48. Teardrop Fracture
The most severe & most unstable of injuries of the cervical spine.
It is characterized by posterior displacement of the involved
vertebra into the spinal canal, fracture of its posterior elements, and
disruption of the soft tissues, including the ligamentum flavum and
the spinal cord, at the level of injury.
Stress applied to the anterior longitudinal ligament causes it either
to rupture or to avulse from the vertebral body, taking along a piece
of the anterior surface of the body.

49. This small,triangular or teardrop-shaped fragment is usually
anteriorly and inferiorly displaced .
Associated spinal cord injury results in the acute anterior cervical
cord syndrome, consisting of abrupt quadriplegia and loss of pain
and temperature distinction; but posterior column senses are
usually preserved.
“Extension teardrop” fracture is completely different; it is a
stable fracture without the potentially dangerous complications of
the flexion type of injury, and usually occurs at level of C-2 or C-3

52. Unilateral interfacet dislocation
Unilateral interfacet dislocation (jumped facet) is due to
hyperflexion injury with rotation.
The superior facet on one side slides over the inferior
facet and becomes locked.
Flexion causes a distraction force of the facets while the
rotational injury around one of the interfacetal joints causes
it to dislocate into the intervertebral foramen.
This results in an anterior subluxation of upper vertebral
body of about 25% of the AP diameter of the body.

53. In the absence of disk space widening or subluxation, unilateral
facet locking is a relatively stable injury.
30% of patients have an associated neurologic defect.

55. On the lateral radiograph, unilateral interfacetal dislocation is
characterized by forward displacement of the vertebral body.
The combination of the anteriorly displaced articular pillar with
its former opposing pillar produces the bow tie sign.
Frontal radiographs reveal upward rotation of the spinous
process of the dislocated segment, the level marked by a sudden
intersegmental rotational deformity.
Oblique projections are necessary to identify the dislocated
facet joint.
 On axial CT, unilateral absence of one facet surface can be
present (naked facet sign), though the appearance of a false joint
can be simulated.

58. Bilateral Interfacetal Dislocation
It is the result of a severe hyperflexion injury and is most often
found affecting C4–C7.
 This injury primarily involves the soft tissues rather than fracture
of the skeletal structures.
Those soft tissue structures that are torn are the posterior
longitudinal ligament, the posterior ligamentous complex, the
annulus fibrosus, and, occasionally, the anterior longitudinal
ligament.
 Disc herniations are common.

59. Bilateral interfacetal dislocation is an unstable lesion that has a high
incidence of cord injuries.
Anatomically, the superior facets are seen to lie fully anterior to the
inferior facets and in such a position are referred to as being locked
because they will not reposition spontaneously.
The body of the dislocated segment is usually displaced anteriorly a
distance greater than one half of the AP diameter of the body below.
On axial CT images the absence of one articular surface at a single
facet joint owing to dislocation may be seen (naked facet sign).

62. Clay Shoveler’s Fracture
Clay shoveler’s fracture is an avulsive injury of spinous process.
Deriving its name from its common occurrence in Australian clay
miners in the 1930s.
It results from abrupt flexion of the head, such as is found in
automobile accidents, diving, or wrestling injuries or from repeated
stress - caused by the pull of the trapezius and rhomboid muscles on
the spinous process.
The spinous avulsion most commonly occurs at C7, with C6 and T1
also frequently involved.

63. Clay-shoveler's fracture is a stable fracture, the posterior ligament
complex remaining intact.
The best radiographic projection for demonstrating this injury is
the lateral view of the cervical spine.
On the lateral projection an oblique radiolucent fracture line
through the base of the spinous process or distal tip may be visible.
This fracture can also be identified on the anteroposterior view by
the so-called ghost sign (Double spinous process sign) produced by
displacement of the fractured spinous process.

65. Thoracolumbar
spine- Injury

67. In the upper thoracic spine the center of gravity
is anterior to the spine.
Axial loading will result in compressive forces
anteriorly and tensile forces posteriorly, resulting
in flexion-type of injuries.
In the lumbar spine due to lordosis,
the center of gravity is posterior.
Flexion type of injuries will straigthen
the lumbar spine and result in axial
loading, resulting in burst fractures.

68. Compression Fracture
The most common site for thoracic spine compression fracture is
between T11 and T12 owing to a combination of axial and flexion
injury- Trivial trauma in a osteoporosis.
Compression fractures between the T4 and T8 segments
occasionally occur in association with convulsive seizures or electric
shock therapy as result of violent contractions of the thoracic and
abdominal muscles.
Most compression fractures in thoracic spine are wedge shaped,
with little chance of neurological deficit unless there is significant
retropulsion of fragments into spinal canal.

70. Compression fractures are the most common fractures of the lumbar
spine. They result from combined flexion and axial compression.
The most common segmental level is T12–L1.
The incidence of vertebral fractures increases with age.
In elderly, osteoporosis precipitates spontaneous compression
fractures during everyday activities- Insufficiency fractures (grandma
fracture). These most commonly occur in women.
Long term corticosteroids (15%), hyperthyroidism (8%), and
malignancy(> 2%).

71. Post-fracture stability is determined based on the classification by
Denis.
 If two or more compartments are disrupted the fracture complex is
unstable.
 The likelihood of neurological injury is high and interventional
surgery is likely to be necessary.

72. Radiographic Signs of Vertebral Compression Fracture
Lateral radiographs best demonstrate fracture features.
The Step Defect- The anterior aspect of the vertebral body is
under the greatest stress, causing buckling of the anterior cortex,
usually near the superior vertebral endplate. Superior endplate is
compressed in flexion, a sliding forward of the vertebral endplate
occurs, creating this roentgen sign.

73. Wedge Deformity- An anterior depression of the vertebral body,
creating a triangular wedge shape. It may create angular kyphosis in
the adjacent area. The superior endplate is involved more often than
the inferior endplate.
Up to 30% or greater loss in anterior height may be required before
the deformity is apparent.

74. Linear White Band of Condensation (Zone of Impaction)-
Occasionally, a band of radiopacity may be seen just below the
vertebral endplate that has been fractured. Represents the early site
of bone impaction following a forceful flexion injury where the
bones are driven together.
Denotes a fracture of recent origin (< 2 months duration).

75. Paraspinal Edema-In cases of extensive trauma U/L or B/L paraspinal
masses may occur, which represent hemorrhage. Best seen on AP
projection- as densities or bulges in psoas margins.
Abdominal Ileus- May occur in severe spinal trauma & is a warning
sign to observer that trauma is severe & chance of fracture is great.
Seen as excessive amounts of small or large bowel gas in a slightly
distended lumen. Result of disturbance to visceral autonomic nerve
from pain, paraspinal soft tissue injury, edema, or hematoma.

77. Traumatic vs Pathological

78. Burst Fractures
A burst fracture is a specific form of compression fracture of vertebral
body wherein a posterosuperior fragment is displaced into spinal canal.
Considerable forces of axial compression and flexion create a burst
fracture.
 Posteriorly displaced bone fragments may cause neurological injury in
upto 50% of cases to the spinal cord, conus medullaris, or cauda equina,
which is best demonstrated by CT and MRI.

79. Chance or Lap Seat Belt Fracture
Chance described - a peculiar fracture of vertebra consisting of
horizontal splitting of spine & neural arch, ending in an upward curve
usually reaching the upper surface of body just in front of neural
foramen.”
The most common location- Upper lumbar spine (L1–L3). Internal
visceral damage may also occur, such as rupture of spleen/ pancreas
/tears of the small bowel & mesentery.

80. This fracture has also been referred to as a fulcrum fracture of the
lumbar spine.
The mechanism of injury is produced by the seat belt acting as a
fulcrum over the abdomen, creating flexion and distraction forces in the
lumbar spine.

81. The posterior and middle columns fail, and different patterns have been
described:
• Chance fracture- Horizontal splitting of spinous process & pedicle
continuing into posterior vertebral body to involve superior endplate.
• Horizontal splitting fracture- Horizontal division of spinous process,
pedicle & posterior vertebral body without involvement of endplate.
• Smith injuries- Rupture through interspinous ligaments partially
rupturing intervertebral disc (type A), avulsing posterior inferior corner
of vertebral body(type B) , fracturing superior articular process (type C).
Neurological deficit occurs in 15% of cases.

82. AP radiograph- A clear transverse fracture through posterior elements
& angulation of superior portion of fractured vertebra leaves a wide
radiolucent gap between two fractured segments- Empty vertebra sign.
Lateral radiograph - Radiolucent split through spinous process, lamina,
pedicle & upper corner of the posterior aspect of vertebral body-
Characteristic of chance fracture.
Constant feature is transverse fracture without dislocation/ subluxation

83. Whiplash Syndrome
The injury follows a forced hyperextension–hyperflexion of the cervical
spine, most commonly associated with rear-end motor vehicle collision.
The most contemporary and appropriate term appears to be cervical
sprain–strain injury.

84. As many as 85% of these patients may have as their pain source the
cervical facet joints.
Imaging of whiplash injuries is limited to or is dominated by soft tissue
rather than osseous abnormalities.
Exclusion of fractures and dislocations is the first priority.
Identification of soft tissue injury is often difficult and limited by
technical restraints of the imaging modality employed.

85. A wide variety of presentations is found, ranging from relatively minor
complaints to severe incapacitation.
Posterior neck pain is the cardinal manifestation, either dull and aching
with exacerbation on movement, sharp related to movement, or a
combination of the two.
Pain may also radiate to the head/shoulder/arm, or interscapular region.
Conventional Imaging
The most important view is the lateral, which is positive in 70 –90% of
cases.
Three key areas for review for evidence of extra-osseous injury are the
soft tissues, vertebral alignment, and joints.

86. Abnormal Soft Tissues
As many as 20% of motor vehicle accident patients presenting to an
emergency department may have pre-vertebral swelling.
Widened retropharyngeal space
Widened retrotracheal space
Displacement of prevertebral fat stripe
Tracheal deviation & laryngeal dislocation
Soft tissue emphysema

88. Abnormal vertebral alignment
Loss of the lordosis
Acute kyphotic angulation
Widened interspinous space
Altered flexion patterns
Vertebral body rotation

90. Abnormal joints
Widened median atlantoaxial joint (ADI)
Widened or narrowed intervertebral disc
Displaced ring epiphysis
Widening of the facet joints.

91. CT
The primary role of CT is in the detection and assessment of fractures,
disc herniations, prevertebral lesions and hematomas and relationship
of bone fragments to the cord.

92. MR Imaging
Discovertebral endplate separations
Anterior longitudinal ligament injuries
Occult endplate fractures
Disc herniation
Cord contusion
Prevertebral edema or hematoma

94. Spinal cord injury without radiological
abnormality (SCIWORA)
Originally referred to as spinal cord injury without radiographic or
CT evidence of fracture or dislocation.
With advent of MRI , term has become ambiguous "Spinal cord
injury without neuroimaging abnormality" - more correct name.
This type of mechanism is reproduced in rear-end motor-vehicle
collisions and direct anterior craniofacial trauma.
Mostly in pediatric population (range: birth to 16 years old)-20%
of all pediatric spinal cord injuries.

95. Inherent elasticity in pediatric cervical spine can allow severe spinal
cord injury to occur in absence of x-ray findings.
96% of patients older than the age of 40 years with SCIWORA had
severe cervical spondylosis.
SCIWORA is mainly a diagnosis of exclusion.
Wide spectrum of neurologic dysfunction,ranging from mild,
transient spinal cord concussive deficits to permanent , complete
injuries of the spinal cord.
Transient neurologic deficit(ie, paraparesis /quadriparesis) /persistent
subjective symptoms (ie, numbness or dysesthesias) suggest SCIWORA
diagnosis.

96. Following findings on MRI have been recognized as causing primary or
secondary spinal cord injury:
Intervertebral disk rupture.
Ligamentous bulging
Spinal epidural hematoma.
Cord contusion.
Hematomyelia
Prognosis of SCIWORA is actually better than patients with spinal
cord injury and radiologic evidence of traumatic injury..

97. Thank you….