Injuries and Diseases
|Whiplash can be classified as an acceleration-deceleration
injury during which indirect forces are transferred to
the neck.It may result from rear-end or side-impact motor
vehicle collisions, but can occur during diving and other
mishaps. The impact may result in bony or soft-tissue
injuries which may lead to a variety of clinical manifestations.The
term whiplash has a common usage, but is controversial
and has no universal understanding or acceptance of its
definition. The more proper term is "cervical spine
Occasionally, an injury of this type is called a "cervical
In a rear-end collision, the body is propelled in a forward
direction. The head abruptly moves backward, necessitating
acute hyperextension of the cervical spine. This is followed
by a recoil of the head with severe cervical neck flexion
and finally a return to the neutral position. The opposite
sequence occurs in head-on collisions.
Neck injuries often result from automobile accidents.
Approximately 60 percent of the patients who are injured
in a car accident and who go to a hospital will have neck
pain. This is a condition that may affect all adults,
but appears to be more common in the age group of 30 to
50. The female:male ratio is 5:1, which is remarkable
since there is a male preponderance in all other motor
vehicle injuries. The symptoms last more than 6 months
in 75 percent of whiplash patients who lose an average
of 8 weeks of work.
The neck can also be injured in a hyperflexion injury.
There may be compression of the anterior column and injury
to the cervical extensor muscles. Therefore, the typical
whiplash injury may have both a hyperextension and a hyperflexion
component. The initial motion is of hyperextension, followed
by a rebound element of hyperflexion.
The frequency of whiplash-associated disorders is high,
the residual disability of the patients is significant
and the costs of care are sizable and rising. There is
considerable inconsistency in the medical community about
appropriate diagnosistic criteria , therapeutic interventions
and the role of rehabilitation.
However, multiple, well-controlled studies have shown
that cervical facet joint injury is the most common basis
for chronic neck pain after whiplash . This condition
cannot be diagnosed other than by using specific diagnostic
Mechanism of Injury
The majority of cases result from motor vehicle accidents
or sporting injuries. The classical description is of
a rear-end accident. This causes an acceleration of the
trunk, with the head being left behind relative to the
body, producing a hyperextension injury of the neck. Because
of the speed of the movement there is no time for the
normal protective muscle reflex contraction to occur,
which would ordinarily protect against such a hyperextension
injury. If there is a head rest, the degree of hyperextension
can be limited. Without that physical restraint there
is nothing to stop the head until it hits the midscapular
region of the back.Following this initial movement, the
trunk is then held either by the safety belt or steering
wheel and the head and neck now flex forward. The degree
of flexion is limited physically limited by the chin hitting
There are multiple structures in the neck that have been
proven capable of causing pain including ligaments, intervertebral
discs, facet joints, muscles and nerve roots.A severe
sprain of the neck will cause subluxation of the facet
articular surfaces. In patients who have neck pain for
more than 6 months following a whiplash injury, the cervical
facet joints are the responsible etiology in more than
Another structure that may be stretched with resultant
pain includes the anterior longitudinal ligament. Spasm
of the interscalene muscles may be responsible for vague
radicular symptoms in the upper extremities such as tingling
of the hands and fingers.
Many patients who suffer from a whiplash injury report
chronic severe headache symptoms. The headache may be
limited to the occipital area or spread to include the
vertex, temple, frontal and retrobulbar areas as well.
Pain is described as dull, aching and squeezing with occasional
pounding and throbbing components. The cervical pain is
aggravated by movements of the neck. The head and neck
pains persist for days or weeks and in some cases become
chronic and last for months or longer.
Exacerbation of pre-existing arthritic or discogenic disease
may occur. In some cases, the occipital neurovascular
bundle at the level of the occipital ridge may be traumatized
secondary to prolonged muscle contraction. Injuries to
the superficial and deep structures of the neck, involving
muscle, ligaments, discs, bone or nerve roots produce
cervical pain that may be referred to the head. Other
causes include injury of the trapezius muscle insertion
or subluxation of higher cervical spine segments. These
headaches usually originate at the base of the skull and
may have a forward radiating component.
CLINICAL CLASSIFICATION OF WHIPLASH
Grade 0: No Neck pain. No physical signs.
Grade I: Neck complaints. No physical signs.
Grade II: Neck complaints. Musculoskeletal signs are present.
Grade III: Neck complaints. Neurologic changes are present.
Grade IV: Neck complaint of pain. Fracture or dislocation
Whiplash syndrome is more properly termed "cervical
spine hyperextension injury" and is commonly the
result of a rear-end motor vehicle accident, but other
mechanisms of injury are possible. The frequency of whiplash-type
injuries is high following certain types of accidents,
and the residual disability can be significant with symptoms
lasting more than 6 months in many patients suffering
from this condition.
Recently, a clinical classification of whiplash associated
disorders has been suggested that grades the patient based
upon subjective and objective findings. (Please see the
previous edition of The Pain Management Letter for this
Following a whiplash-type injury, neck pain and other
symptoms may be delayed 24 to 48 hours. The pain is usually
a dull ache radiating from the midcervical spine up to
the occiput. It may spread laterally into the trapezius
muscles, and may radiate into the upper extremities. Movement
and any physical effort tend to aggravate pain symptoms.
Cranial symptoms include headaches, dizziness, visual
disturbances and tinnitus. A small percentage may complain
of arm or hand numbness.
Many patients do not seem to have significant objective
signs on physical examination. If present, they are reduced
range of motion in the cervical spine. Swelling is rarely
seen. Cervical muscle spasm may be present. If peripheral
neurologic signs are present, it may indicate a more severe
injury such as intervertebral disc disease.
Plain radiographs in several views should be performed
as part of the initial evaluation. This includes an anteroposterior
view, lateral view in extension and flexion, oblique views
and a odontoid view. Some patients may have an abnormal
curve pattern on the lateral X-ray with loss of cervical
lordosis and even a reversal of the curve. This is usually
associated with spasm of the paravertebral muscles and
is neither a fixed nor structure deformity. Cervical spondylosis
should be noted since this is associated with more severe
and prolonged symptoms. If neurologic injury is suspected,
patients should be evaluated with more involved testing
such as MRI exams or EMG studies.
Treatment of Whiplash Associated
A timeline for treatment of WAD has been recommended.
This timeline refers to patients with Grade I through
III injury. Patients with Grade IV require immediate surgical
consultation. The clinical management of WAD patients
should recognize that most cases of whiplash unassociated
with other injuries are usually self-limiting.
Thus reassurance, promotion of activity and conservative
management are recommended in early treatment for Grades
I to III. The most important principle of treatment is
to prevent the development of a chronic pain syndrome.
Acute Mild Injury
Treatment must be initiated early, preferably within hours
of the injury, but no longer than a few days. Treatment
must be aggressive but gentle. Soft tissue injury may
involve inflammation, edema and possible microscopic hemorrhage.
Immediate rest of the neck is indicated. A soft collar
allows support of the head. Early use of ice (within 24
hours) is indicated to decrease pain, and reduction of
edema and hemorrhage.
Following this early period (24-48 hours) the use of heat
is indicated to promote blood flow. Heat causes vasodilation
and increases blood flow to wash out the accumulating
toxins. Heat is also sedative and soothing. Prolonged
use of ice becomes painful and causes vasoconstriction
and additional local ischemia. Lengthy use of a soft cervical
collar is contraindicated. Within several days, a collar
becomes addictive and prolonged immobilization allows
stiffening of cervical structures and deconditioning of
supporting muscles. Active and carefully guided passive
range of motion is indicated.
Acute Severe Hyperextension Injury
A severe injury implies significant injury far exceeding
that of the mild acute injury. In an injury of this nature
there may be tear or avulsion of the anterior longitudinal
ligament, tear of the anterior flexor muscles or tear
of the annular layers of the intervertebral disk. Skeletal
damage may be present and injuries of this nature require
Chronic Whiplash Pain
Cervical pain that lasts longer than 2-3 months should
be considered chronic in nature. This type of pain requires
aggressive evaluation and treatment to prevent a permanent
In patients who have neck pain for more than 6 months
following a whiplash injury, the cervical facet joints
are responsible in approximately 60-80 percent. Multiple,
well-controlled studies have shown that cervical facet
joint injury is the most common basis for chronic neck
pain after whiplash . This condition can only be diagnosed
by using specific diagnostic nerve blocks.
Therefore, patients who fall into this category should
undergo diagnostic cervical facet joint injections. If
greater than 50-60% of the pain symptoms are relieved
with this diagnostic approach, the patient should be considered
an appropriate candidate for radiofrequency thermocoagulation
of the responsible spinal nerves. This technique is safe
and reliable, and can provide long-lasting relief of pain.
Resolution of chronic neck pain can also provide reduction
of pre-operative psychological stress.Many times, the
psychological distress exhibited by whiplash patients
is a consequence of the chronic somatic pain.