Download Cervical Spine Injuries in the Athlete

Cervical Spine Injuries in the
Athlete
Key Points
• If the space available for the spinal cord is
reduced because of a narrow canal, an athlete
is at greater risk
• Cord compression can be anticipated when
the diameter of the midsagittal cervical spinal
canal is 10 mm or less
• Cervical spine injuries can be classified as
either catastrophic or noncatastrophic
• The initial evaluation follows the ABCDE
sequence of trauma care
• Distinct regional differences exist
between the upper cervical spine and
the lower cervical spine
• The occipit and the first two vertebrae
make up the upper cervical spine
• The atlas (C1) is a bony ring that
articulates with the occipital condyles
• The axis (C2) has a true vertebral body,
from which the odontoid process, or
dens, projects.
• The major stabilizing force at this joint is
the transverse atlantal ligament (TAL).
• TAL crosses posterior to the dens and
attaches to C1 on both sides; this
prevents anterior translation of the atlas
on the axis.
• This specialized osseo-ligamentous
anatomy allows C1 to rotate on C2 in a
highly unconstrained manner, providing
60% of all cervical rotation
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The lower cervical spine consists of the C3
through C7 vertebrae
Two contiguous vertebrae and supporting soft
tissues make up a motion segment
Motion segments can be separated into an
anterior and a posterior column
The anterior column include the posterior
longitudinal ligament and all structures ventral
to it
The posterior column consists of those
structures dorsal to the posterior longitudinal
ligament.
ALL, anterior longitudinal ligament; D, division between anterior and posterior column; F, facet articulation; FC, facet
joint capsule; IAP, inferior articular process; IS, interspinous ligament; IVD, intervertebral disc; PLL, posterior
longitudinal ligament; SAP, superior articular process; VB, vertebral body
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Stability of a cervical motion segment is derived mainly from the anterior column elements
The vertebral bodies and inter-vertebral discs provide the majority of resistance to
compression.
The surrounding paraspinal musculature and ligaments that resist shear forces.
• The cervical spinal canal is
funnel shaped from
cephalad to caudal.
• The cord occupies less than
half the canal's crosssectional area at the level
of the atlas, but this space
reduces significantly in the
lower cervical spine.
• Almost 75% of the crosssectional area of the canal
is occupied by the larger
spinal cord between C4
and C7
• The diameter of the midsagittal cord
averages between 8 and 9 mm
• A range of 14 to 23 mm exists for the
vertebral canal at the corresponding
level
• Criteria for radiographic stenosis are
anteroposterior dimensions
measuring less than 13 mm on a
lateral radiograph
• When the diameter of the midsagittal
cervical spinal canal is 10 mm or less,
cord compression can be anticipated
• Pavlov's ratio (canal-vertebral body
width):
- should be 1.0, with < 0.85
indicating stensosis;
- ratio of < 0.80 is a significant
risk factor for lateral neurologic injury
Catastrophic Cervical Spine Injuries
• Defined as a structural distortion of the cervical
spinal column associated with actual or potential
damage to the spinal cord
• Include
– Unstable fractures and dislocations,
– Transient quadriplegia, and
– Acute central disc herniation
• Only a very small percentage
• Usually affect the extremities in a bilateral
fashion
Non-Catastrophic Cervical Spine
Injuries
• The vast majority of injuries are noncatastrophic. These
injuries include
– Neuropraxia of the cervical root or brachial plexus (known as a
“stinger” or “burner”)
– Paracentral intervertebral disc herniation,
– Stable fractures,
– Spinal ligament injury, and
– Intervertebral disc injury
• Injured athletes display clinical findings in
– (a) a single upper extremity,
– (b) the neck and arm, or
– (c) the neck only
Unstable Fractures and Dislocations
• Make up the majority of catastrophic spinal injuries in
athletes
• Loss of the ability of the spine, under physiological
loads, to maintain its premorbid patterns of motion, so
there is no initial or additional damage to the spinal
cord or nerve roots
• Most fractures and dislocations in injured athletes
occur in the lower cervical spine.
• In football, mainly
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compression injury (axial loading).
Hyperflexion.
Hyperextension,
lateral stretch, and
congenital instability also have been reported in cervical
spine injury
Hyperflexion Injuries
• Flexion-Compression Injuries
– Teardrop Fracture
– Burst Fracture
• Flexion-Distraction Injuries
– Unilateral Facet Dislocation
– Bilateral Facet Dislocation
Most influential in determining specific injury
patterns is the neck position at the time of
impact
Neutral alignment leaves the cervical spinal
column slightly extended because of the
normal lordotic posture
Compressive forces in this position are
dissipated by the anterior paravertebral
musculature and vertebral ligaments (anterior
longitudinal ligament)
Slight flexion will eliminate cervical lordosis
Direct force along the spine's longitudinal axis
will result in large forces being transferred
directly to the vertebrae as opposed to the
surrounding soft tissues
Cadaveric studies have shown that the
cervical spine, when straight and colinear with
the applied load, responds to compression by
buckling
A: With the neck in neutral alignment, the vertebral column
is extended. The compressive force can be dissipated by the
spinal musculature and ligaments. B: With the neck in a
flexed posture, the spine straightens out and becomes
colinear with the axial force. C: At the time of impact, the
straightened cervical spine undergoes a rapid deformation
and buckles under the compressive load
Burst Fracture
• Pure Vertical Compression (the
cervical spine is slightly flexed,
eliminating the normal lordosis)
results in equal force on the
anterior and posterior columns,
which may result in an axial
loading fracture (“burst”)
• Intradiscal pressure rises such
that the adjacent end plate
fractures and fails
• Bone fragments often can
displace in all directions
secondary to forced, extruded
disc material within the vertebral
body.
• These burst fractures are notable
for retropulsion of osseous
material into the spinal canal.
In the “burst” fracture variant, comminution of the
vertebral body can be associated with retropulsion
of osseous fragments into the spinal canal
Teardrop Fracture
• Results from a compressive–flexion
injury is present as a result of a
combination of axial force and
bending
• The anterior column shortens
under loading. We then see
compressive failure of the vertebral
body and tensile failure of the
posterior spinal ligaments
• This pattern can be highly unstable
both anteriorly and posteriorly,
with displacement of the anterior
fracture and widening of the
posterior elements, and it often
may be associated with spinal cord
injury
The “teardrop” fracture variant is characterized by
compressive failure of the anterior column with a coronal
plane fracture extending through the vertebral body.
Tensile forces cause disruption of the posterior spinal
ligaments
Flexion–Distraction Injuries
• Can be created either by a direct
blow to the occipital region or by a
rapid deceleration of the torso
• The most common injury is
bilateral facet dislocation
• An axial rotation force in
conjunction with the flexion–
distraction injury may produce a
unilateral facet dislocation (spinal
cord injury in up to 25% of cases)
Lateral cervical spine radiographs showing bilateral facet dislocation of C6 on C7. This pattern of injury results from disruption
of the supraspinous and interspinous ligament, facet capsules, ligamentum flavum, posterior longitudinal ligament, and the
dorsal portions of the annulus fibrosus. The soft tissue damage can be associated with fractures of the superior articular
processes. B: Unilateral facet dislocation usually is caused by the combination of flexion and rotational forces. The addition of
shear or compressive forces can cause fracture of the articular process
Upper cervical spinal fractures and
dislocations
Although significant injuries, rarely cause spinal cord damage
The spinal canal in the upper cervical region has a much greater
proportion of space to spinal cord.
Therefore, even with displacement, cord compression is unlikely in
relation to upper cervical spinal injury.
In fact, a burst fracture of the atlas (Jefferson fracture) and
traumatic spondylolisthesis of the axis (Hangman fracture) expand
the dimensions of the spinal canal, making cord compression and
neurological injury improbable.
Odontoid fractures or ruptures of the transverse ligament will
destabilize the atlantoaxial joint.
Typically, high cervical cord injuries can cause respiratory
compromise secondary to high-cord/low-brainstem injury as well as
diaphragmatic paralysis from trauma to the anterior horn cells of
the phrenic nerve
Transient Quadriplegia
• A momentary cord compression at
the extremes of neck extension or
flexion (The Pincer Mechanism)
• Congenital cervical stenosis may
predispose
• A Pavlov ratio of less than 0.8 was
documented in 93% of football
players with cervical cord
neuropraxia
• S&S of transient quadriplegia include
pain, tingling, or loss of sensation
bilaterally in the upper and/or lower
extremities.
• A mild quadriparesis usually exists,
but usually no motor weakness
• Rarely complete quadriplegia also is
possible
• May last from 15 minutes to 48
hours, but full recovery often is
expected
The “pincer mechanism” effect of hyperextension
causes dynamic compression of the spinal cord
between the end plate of the cranial vertebral body
and the spinolaminar line of the subjacent vertebra
Intervertebral Disc Herniation
• Extrusion of the
nucleus pulposus
posteriorly can cause
acute cord compression.
• Unlike the more
common lower
lumbar disc herniations, cervical
disc herniations can produce permanent cord injury.
• Posterior neck pain, paraspinal muscle spasm, and
either transient or permanent acute paralysis are the
most common symptoms.
• Radiating (radicular) pain or referred pain unilaterally
down the shoulder and arm also may be present
Congenital Spinal Anomalies
• Many are completely asymptomatic,
discovered at the time of injury
• Predispose athletes to certain forms
of spinal cord injury
• Klippel-Feil syndrome, which reduces
the number of motion segments in
the spine, may lead to progressive
instability or degenerative stenosis.
• Multiple fusions in the cervical spine
in this condition make it difficult to
dissipate loads that are applied to the
cervical spine
• Hypoplasia of the dens (i.e., a failure
of formation involving the second
vertebra) and developmental os
odontoideum can both result in
atlantoaxial instability
Noncatastrophic Cervical Spine
Injuries
• Neuropraxia of the cervical root or brachial
plexus (the “stinger” or “burner”)
• Paracentral intervertebral disc herniation
• Stable fractures
• Spinal ligament injury
• Intervertebral disc injury
Neuropraxia of a cervical nerve root
or the brachial plexus
• Foraminal compression of a nerve root from
forceful neck extension and rotation toward
the affected side
• Traction (tensile forces) may injure the
brachial plexus, resulting in a neuropraxia
Signs and symptoms
• Burning pain, weakness, or paresthesias in the
shoulder girdle and arm.
• Neck tenderness usually is absent, and range of
motion often is full
• Transient motor, sensory, and/or reflex deficit can
occur, but these symptoms resolve within several
minutes.
• Some athletes may not gain full strength until 24
to 48 hours later.
• Although muscle weakness is variable, it is
unlikely to represent permanent motor loss
Paracentral disc herniation
• A tear in the posterolateral
aspect of the annulus fibrosus
allows the nucleus pulposus to
protrude posteriorly
• Causes range from high-energy
impact loading to a minor
twisting injury to the neck
• Cause unilateral upper limb and
neck symptoms associated with
nerve root compression
• Monoradiculopathy,
paresthesias, and/or weakness
in the upper extremity often are
present
• Spasm and neck pain almost always are
present.
• Localized neck symptoms usually signify more
minor injuries
– stable fractures,
– spinal ligament injuries (cervical sprains),
– intervertebral disc injury
Stable Fractures
• Stable fractures of the anterior column generally
are secondary to compressive forces
• Fractures of the posterior elements typically
result from a hyperextension injury
Management of Cervical Spine
Injuries
• Primary Survey
• Assess for immediately life-threatening conditions and to
prevent further injury. The initial evaluation follows the
ABCDE sequence of trauma care
• Primary survey will determine how the player is
subsequently treated.
• One of three clinical scenarios will become apparent
Scenario 1: Cardiorespiratory
Compromise