Acute Spinal Injury

In the cognitively intact patient
(including the absence of drugs or alcohol) and cooperative patient,
clinical clearance of the spine may be possible. While case reports
have documented bony and ligamentous spinal injuries in such patients,
unstable spinal injuries or neurologic deterioration in these patients
have not been reported. Accordingly, routine radiographic evaluation in
such cases is not indicated. However, the physical examination findings
of neck or back pain, neurologic abnormalities, bruising, spinal
deformity, pain with active range of motion, or significant
“distracting” nonspinal injury should prompt further investigation.

Obtunded or uncooperative patients, as
well as alert patients with physical examination findings consistent
with spinal injury, should be maintained on spinal precautions until
thorough clinical and radiographic evaluation of the spine has been
completed.

Roentgenograms.
The standard radiographic evaluation of the cervical spine includes the
lateral, open-mouth (odontoid), and anteroposterior plain films. The
lateral view will detect up to 85% of significant cervical spine
injuries provided that the occiput-C1 and C7–T1 junctions are
visualized. Despite normal x-rays of the upper cervical spine and the
absence of clinical findings suggestive of a lower-cervical injury, one
study has detected a 3.1% incidence of occult fractures at the C7–T1
level on computed tomographic (CT) scanning (1).
CT scanning of the upper cervical spine has become the method of
initial evaluation in many trauma centers. While the addition of
orthogonal oblique views does not increase the sensitivity of plain
film evaluation, these views provide excellent visualization of the
cervical posterior elements and foramina. Anteroposterior and lateral
images of the thoracic and lumbar segments are indicated in the
presence of pain or abnormal physical examination findings in these
regions and in cognitively impaired patients who cannot cooperate with
the physical examination. Additionally, because up to 6% of spinal
injuries have a noncontiguous injury elsewhere in the spine, the
presence of an injury anywhere in the spine should prompt radiographic
evaluation of the entire spine.

Important points to consider in interpreting plain radiographs include (Fig. 11-1):

CT scanning
can provide rapid and detailed assessment of the spine. This should
include high-resolution imaging (2- to 3-mm collimation and 1.5-mm
pitch) from the occiput to T1 with sagittal and coronal
reconstructions. Several studies have demonstrated high levels of
sensitivity (90%) and specificity (100%) of screening CT scanning in
polytrauma patients (2,3,4). While CT appears to be a cost-effective primary screening tool in patients at high or moderate risk for cervical injuries (5), CT scanning represents the standard of care in all patients when:

Magnetic resonance imaging (MRI) is less
sensitive, less specific, and less cost effective than the plain film
series or screening CT for the identification and evaluation of
cervical fractures (6). However, MRI is
extremely sensitive and specific for evaluation of the paravertebral
soft tissues, including the spinal cord, intervertebral discs, and
ligamentous structures. Patients with abnormal neurologic findings,
particularly incomplete injuries, should undergo MRI scanning of the
relevant spinal segment(s) to visualize the spinal cord and nerve roots.

Dynamic fluoroscopy.
Passive flexion and extension stressing of the cervical spine,
performed by an experienced physician under fluoroscopy, has a reported
sensitivity of 92.3% and specificity of 98.8% for detecting significant
ligamentous injuries and instability of the cervical spine (7).
While some centers support the use of this technique in clearing the
spine of unconscious patients, the risk of neurologic deterioration may
outweigh its benefits, especially given the widespread availability of
CT and MRI imaging (7).

The anterior cord syndrome
involves loss of neural function in the anterior two thirds of the
spinal cord. Patients with these injuries experience complete loss of
motor function and of pain and temperature sensation but retain
sensations of vibration, proprioception, and light touch. These
preserved functions result in an improved prognosis.

The posterior cord syndrome
is characterized by loss of proprioception and vibrational sensation.
Motor function and gross touch sensation typically are spared due to
the ventral location of the descending motor tracts and spinothalamic
tracts, respectively. The prognosis in posterior cord syndrome is fair.

The central cord syndrome
is typically associated with a cervical hyperextension injury, often in
older patients. This syndrome consists of a disproportionately greater
weakness in the upper extremities compared with lower extremities,
various sensory changes at or below the site of the lesion, and urinary
bladder dysfunction. Proposed causes include hematomyelia, contusion,
cord swelling, and ischemia of the cervical spinal cord. The anterior
horn cells at the level of injury may also be involved. The prognosis
depends on the amount of initial neurologic involvement and the
rapidity of subsequent recovery. The signs of neurologic damage tend to
disappear in reverse order of their appearance.

A penetrating injury or unilateral facet dislocation can result in unilateral injury to the spinal cord: the Brown-Séquard syndrome. Patients experience loss of ipsilateral motor and dorsal column function and contralateral pain and temperature sensation.

Methylprednisolone.
The National Acute Spinal Cord Injury Studies (NASCIS I, II, and III)
have studied the use of parenteral methylprednisolone following spinal
injury. NASCIS I detected no benefit in the treatment group, but the
steroid dose used was found to be below the therapeutic threshold in
subsequent animal experimentation (10). In
NASCIS II, patients were randomly assigned to receive a higher loading
dose of methylprednisolone, naloxone (an opioid antagonist), or placebo
within 12 hours of acute spinal cord injury (11).
While investigators found no overall benefit in the methylprednisolone
group, post hoc analysis of the data suggested small gains in total
sensory and motor scores in a subgroup of patients who had received
drugs within 8 hours of the injury. Naxolone was less effective than
methylprednisolone. Despite the weakness of the data, high-dose
methylprednisolone infusion over 24 hours became the standard of care
in patients treated within 8 hours of acute spinal cord injury. NASCIS
III compared 48-hour infusion with 24-hour infusion and found no
benefit to extending the treatment beyond 24 hours (12).
Again, in post hoc analysis of the data, there appeared to be a benefit
from extending the infusion to 48 hours when treatment began between 3
and 8 hours after the injury. While no other study has verified the
results of the NASCIS conclusions, most centers have adopted the
following protocol:

Mechanism of injury.
The superior articular processes of the atlas face upward, inward, and
slightly backward. A vertical compression force can thrust the
articular facets of the occipital condyles of the skull downward, push
the lateral masses outward, and disrupt the ring of the atlas producing
a C1 ring fracture, as shown in Fig. 11-2 (13).
Less commonly, this same mechanism can produce an occipital condylar
fracture, which can be isolated or associated with a basilar skull
fracture (14).

Anatomic considerations.
The anteroposterior diameter of the ring of the atlas is approximately
3 cm. The spinal cord and the odontoid process each are approximately 1
cm in diameter, approximately one third the diameter of the ring.
According to Steel rule of thirds, the
remaining centimeter of free space allows for some degree of pathologic
displacement. Therefore, anterior displacement of the atlas exceeding 1
cm (the thickness of the odontoid process) threatens the adjacent
segment of cord. This usually occurs with disruption of the transverse
ligament of C1. This ligament maintains the proper relationship of the
dens to C1 and is often ruptured as a pure ligamentous disruption from
a flexion injury. Because the cardiac and respiratory centers lie at
this level, displacement of the atlas threatens the life of the
patient. If the ring of the atlas is capacious (greater than 3 cm in
diameter either as an anatomic feature or as a result of a C1 ring
fracture), there is less danger, whereas if it is narrow and
unfractured, there is more (13).

History. If
consciousness is not lost as a result of a concurrent head injury, the
history should suggest a mechanism for a vertical compression injury.
The injury often results from a diving accident or any mechanism that
applies axial force to the head.

Examination.
Clinical symptoms and signs vary from minimal complaints to severe pain
and gross limitation of movement. Extension usually produces some pain,
but rotation may be relatively pain free. Because the suboccipital
nerve crosses the ring posterior to each lateral mass and the greater
occipital nerve emerges just below the posterior ring of the atlas to
supply the skin over the occiput, testing of sensation can show
involvement of the suboccipital or, more commonly, the greater
occipital nerve. Damage to the spinal cord is uncommon because a
significant cord injury at this level causes immediate death.

Roentgenograms.
Anteroposterior films, including an open-mouth view and a lateral view,
are routine and CT scanning may be indicated. The common fracture sites
are the anterior arch, either midline or just lateral to the midline,
and the posterior arch at its narrowest portion just posterior to each
lateral mass. Displacement of the fracture can be minimal. In an
open-mouth roentgenogram of the odontoid process, when a comminuted
fracture of C1

shows
bilateral overhang of the lateral masses totaling 7 mm or more, a
rupture of the transverse ligament may have occurred, rendering the
spine unstable (Fig. 11-3).

Treatment.
Treat by immobilization in a cervicothoracic orthosis or halo vest
until healing occurs, usually in 2 to 3 months. Initially, use 5 to 8
lb of tong traction in bed while the extent of the injury is assessed.
Reduction of the fracture is best accomplished by adjusting the
relative position of the head to the thorax. Head extension is required
when the transverse ligament is ruptured (14,15).

Mechanism of injury.
The C1 vertebra and the odontoid process of C2 are a single functional
unit. The apical/alar and transverse ligaments on the posterior aspect
of the odontoid process can remain intact following an injury,
producing a fracture of the base of the process. The skull, the C1
vertebra, and the odontoid process of the C2 vertebra then move
relatively independently of the body of the C2 vertebra.

History.
Symptoms can be minimal, but severe pain behind the ears and stiffness
following a flexion or extension injury are frequent. The patients
often report a feeling of instability at the base of the skull and
present themselves by holding their head with both hands. There is
seldom any suggestion of weakness or numbness of the limbs following an
acute injury.

Examination. Tenderness in the suboccipital region may be present. The neurologic examination is generally normal.

Roentgenograms.
A lateral roentgenogram demonstrates that the C1 vertebra has moved in
relation to C2, and it is also usually seen that the anterior arch of
the C1 vertebra and the odontoid process are in their normal
relationship; that is, the odontoid process has been carried with the
arch of the C1 vertebra (16). Translation of C1
or C2 of 3.0 to 4.5 mm, with neurologic symptoms or signs, can indicate
clinical instability. Normally, the position of the posterior part of
the C1 ring is equidistant between the base of the skull and the
spinous process of C2. An open-mouth anteroposterior roentgenogram
usually shows a fracture line at the base of the odontoid process, and
this fracture line may run inferiorly, possibly involving the upper
part of the vertebral body. The fracture must be differentiated from
congenital etiologies such as a secondary ossification center with an
open apophyseal plate, which may be seen in younger patients, or from a
failure of segments of the odontoid process to fuse to the body of C2,
which may be seen in older patients. With a congenital etiology, the
radiolucency usually is situated more cephalad and is less irregular
than that seen with an acute fracture. In addition, an increased
incidence of

anomalies
of the anterior arch of C1 and of the atlanto-occipital articulation is
seen with congenital abnormalities of the odontoid process (15,16,17). CT scans are usually helpful.

Treatment (15,16)

Complications.
As revealed by roentgenography, union of the fracture may not be
achieved in all cases. In a review of 60 odontoid fractures, it was
found that fractures at the junction of the odontoid process with the
body of C2 had a nonunion rate of 36%, which is the usual rate given to
type II fractures (see Anderson and D’Alonzo in Selected Historical Readings).
With type III fractures, only 10% went on to nonunion. It was theorized
that the vertebral body consisted of more cancellous bone, which is
associated with a higher union rate. The use of traction beyond the
first few days is contraindicated because it may produce distraction
and it does not immobilize the fracture. This common practice may
account for the high incidence of nonunion. At 4 months after injury,
flexion and extension films should be obtained. If there is
instability, a posterior C1-C2 fusion should be recommended, although
10% to 15% of neck rotation will be lost (15,16,17).

Mechanism of injury.
Although the hangman causes this injury by distraction and extension,
the other mechanisms of injury that produce the same fracture seem to
be confusing and indefinite. Patients have remembered “hanging” their
chins on the steering wheel or dashboard or striking their foreheads on
the sun visor of cars involved in accidents. The classic injury is a
bilateral fracture passing through the posterior part of the lateral
masses or pars interarticularis of the axis and into the intervertebral
notch (13). The body of the

axis is then subluxated or dislocated in relation to the body of C3.
The skull and C1 move as a unit with the body of C2, while the
posterior elements of C2 remain as a unit with the posterior elements
of C3, as shown in Fig. 11-4.

Examination.
Involvement of the spinal cord in patients who survive the initial
trauma is relatively uncommon, so the patient may complain of little
more than local pain and stiffness. There is, however, tenderness over
the spinous process of C2.

Roentgenograms.
Anteroposterior and lateral roentgenograms and tomograms or CT scans
are essential. The retropharyngeal space may be widened on the lateral
view (normal is 4–6 mm at C3). The injury is occasionally accompanied
by other injuries in the lower part of the cervical spine, and these
must be carefully excluded.

Treatment.
The fracture tends to be reduced with the neck in a neutral position,
but the most appropriate position should be adopted. Halo vest
immobilization should follow a brief 1- to 2-day period of tong
traction and must often continue for 3 months. Traction can produce
distraction and subsequent nonunion or ligamentous instability. If
minimally displaced, a cervical brace (such as a Philadelphia collar)
may be used. The fracture usually heals and primary operative treatment
is unwarranted.

Complications. Patients rarely require intubation or tracheotomy because of initial severe retropharyngeal swelling.

The mechanism of injury is similar to that for the cervical spine extension injuries described in D.1.b.

Likewise, the history is similar; for example, the patient was an occupant in a car that was suddenly struck in the rear by another automobile.

The examination shows tenderness along the scalene muscles and within the body of the trapezius muscle.

In a pure soft-tissue injury without tearing of the anterior longitudinal ligament, the roentgenograms are normal.

Recommended treatment
for the first 10 to 14 days includes a properly sized soft collar to
immobilize the neck, sufficient analgesics for pain relief, and rest.
Soft collars are preferable to rigid collars for comfort. Collars
should be high posteriorly and low under the chin to keep the cervical
spine in a neutral or slightly flexed position. Avoid hyperextension in
whiplash injuries and cervical radiculopathy. Cold packs may be used
for the first 24 hours, followed by warm packs. A folded towel can be
used as a neck collar. Ice may be placed within the towel initially;
then a damp warm towel may be used. Corticosteroid injection of the
facet joints has not been proven to be effective in a randomized
controlled trial (26).

The long-term prognosis for these injuries was reported as follows: 43% of the patients had residual symptoms 5 years after injury (see Hohl in Selected Historical Readings).
There were degenerative changes in 39% of the patients. A poorer
prognosis was predicted if shortly after injury the following findings
were present:

Types of injury (28)

Diagnosis.
The diagnosis is suspected from the mechanism of injury or, in the
elderly patient, following a sudden jolt or fall. Tenderness to
palpation or

percussion over the involved segment is common. Hematomas and gaps between spinous processes may be palpable.

Examination.
On initial examination, a neurologic assessment must be completed. If a
sensory level is detected, mark it on the chart and on the trunk with
the time and date of examination. If there is any motor deficit, then
record it on a simple muscle chart. It is sufficient to record function
of muscle groups rather than of individual muscles. A drawing of the
patient can be helpful to illustrate pertinent neurologic findings. A
flow sheet is another useful device to document changes in the
neurologic status over time.

Roentgenograms.
Excellent quality anteroposterior and lateral films are required, and
CT scans often are indicated to evaluate the posterior elements and to
assess stability (28). The pattern of injury
must be accurately determined. If there is neurologic involvement and
the roentgenograms and CT scans do not reveal a fracture, MRI is
indicated. This study identifies herniated disc material or hematoma as
the cause of the deteriorating neurologic examination (30,31).

Treatment. Logroll the patient on a firm mattress until stability of the fracture is assessed.