INTRODUCTION
Whiplash neck injury is a term commonly used to describe a particular
type of soft tissue neck injury. The term whiplash neck injury, as used
in this paper, refers to an injury to the soft tissues in the neck, of
an occupant of a stationary
motor vehicle, which is struck directly from behind by another vehicle.
Although there are many similarities between whiplash neck injuries and
other varieties of soft tissue neck injuries, this paper deals specifically
with whiplash neck injuries.
There is unfortunately a degree of vagueness or overlap of meaning of
the terms whiplash neck injury and other similar terms when used by various
medical practitioners, patients, lawyers, insurers etc. For this reason
the relevant terms are defined below to indicate their meanings in the
context of this paper.
Injuries to bone are called fractures. All neck injuries which do not
involve fractures can therefore be called soft tissue neck injuries.
BASIC ANATOMY OF THE NECK
As in the rest of the body, the neck consists of bone and soft tissues.
The bones of the neck are called vertebrae, each of which consists of
a vertebral body in front, and a ring of bone [pedicles and laminae] at
the back, which encircles the spinal canal. In-between adjacent vertebrae,
on the left and right sides, are a pair of intervertebral foramina. The
seven cervical vertebrae, stacked on one another, together form the cervical
spine.
The term soft tissue is a nonspecific term used to describe all and any
tissues in the neck excluding bone. The most sensitive and important soft
tissues in the neck are the neurological structures, namely the spinal
cord, nerve roots, and peripheral nerves.
The spinal cord, which is contained and protected in the spinal canal,
conveys information between the brain and the rest of the body.
The nerve roots in the neck, which emerge at each level from the spinal
cord and exit the spinal canal through the intervertebral foramina, convey
information between the spinal cord on the one hand, and the head, neck,
shoulders, arms and hands on the other.
The peripheral nerves are extensions of the segmental nerve roots, which
arise by way of division and joining of nerve fibers from different nerve
roots.
The brachial plexus is a major conglomeration of nerves in which nerve
fibers from different segmental nerve roots in the neck are distributed
to the peripheral nerves that innervate [provide nerve supply to] the
upper limb.
Although the spinal cord and segmental nerves are in fact soft tissues
as defined above, they are generally referred to specifically, and are
not generally included in the meaning of the term soft tissues. Terms
such as spinal cord injury, nerve root injury, brachial plexus injury,
etc. are used when neurological structures are injured. Neurological injuries
may of course coexist with fractures and with other soft tissue injuries.
The term soft tissue neck injury is generally used to indicate injury
to one or more of the following non-neurological soft tissues in the neck
: -
Muscles, which attach to the skull and vertebrae, and which by their
contraction cause the head and neck to move, or by sustained contraction
maintain stable postures or positions of the head and neck.
Ligaments, which are tough fibrous structures attached to the skull and
vertebrae, and which secure the column of bones forming the cervical spine,
thereby preventing excessive translation or separation of bony structures
during neck movements.
Intervertebral joints, including the cartilaginous joint surfaces, as
well as the joint capsules, which consist of short ligaments around the
periphery of the joints, attached to and securing the adjacent articular
processes [bony extensions of adjacent vertebrae which form joints with
one another].
Intervertebral discs, principally the annulus fibrosis, which consists
of more or less vertically arranged ligaments around the periphery of
the discs, which contain the central nucleus pulposis, and which secure
the adjacent vertebral bodies to one another.
MECHANISM OF INJURY
Whiplash neck injuries occur when a stationary vehicle is struck directly
from behind by another vehicle. The initial force occurs as the stationary
vehicle is rapidly propelled [accelerated] forwards.
The seat of the occupant rapidly propels [accelerates] the torso and
limbs of the occupant forwards. The head of the occupant, which is not
supported by the seat, remains behind by virtue of its inertia.
These forces result in hyperextension of the neck.
Extension refers to the normal backwards curvature of the neck when the
head is moved backwards to look up.
Hyperextension of the neck indicates an extension movement beyond the
normal physiological range, or an extension movement brought about by
excessive force.
When the neck is forcefully moved into hyperextension, the anterior [front]
structures of the cervical spine are subjected to a separation strain
or tensile strain, while the posterior [back] structures of the cervical
spine are subjected to a compression strain.
The subsequent force occurs as the accelerated vehicle slows down and
stops, either by braking and friction of its tyres on the road, or more
abruptly by colliding with another vehicle in front.
The forward motion of the torso and limbs of the occupant is rapidly
stopped [decelerated] by the seatbelt. The head of the occupant, which
is unrestrained, continues to move forward and then downward until the
chin strikes the chest.
These forces result in hyperflexion or flexion-compression of the neck.
Flexion refers to the normal forwards curvature of the neck when the
head is moved forwards to look down.
Hyperflexion of the neck indicates a flexion movement beyond the normal
physiological range, or a flexion movement brought about by excessive
force. Contrary to hyperextension of the neck, the neck is protected from
hyperflexion to a large extent by the chin abutting on the chest.
Flexion-compression of the neck indicates a downwards compressive strain,
caused by the momentum of the head moving downwards, associated with the
forward bending flexion strain.
When the neck is subjected to hyperflexion or flexion-compression strain,
the anterior [front] structures of the cervical spine are subjected to
a compression strain, while the posterior [back] structures of the cervical
spine are subjected to a separation strain or tensile strain.
The above represents a simplified explanation of the relevant injuring
forces. It is known that the actual situation is more complex, and that
the neck is additionally subjected to vertical [upwards and downwards]
forces at different moments during acceleration and deceleration, and
that at certain moments in time the neck is subjected to S-shaped deformity
with compression.
PATHOLOGICAL NATURE OF WHIPLASH INJURY
During hyperextension strain, anteriorly situated muscles and ligaments,
as well as the anterior annulus fibrosis of intervertebral discs are sprained,
and in more severe cases may even be disrupted.
Disruption of a muscle or ligament refers to tearing with separation
of all fibers of the structure.
Sprain of a muscle or ligament refers to damage by stretching and/or
tearing of individual fibers within the structure, but without disruption
of the entire structure.
In addition the anterior separation strain may result in microfractures
of vertebral end plates, as well as separation of intervertebral discs
from vertebral end plates.
Vertebral end plates are the horizontal plates of hard bone at the bottom
ends and top ends of vertebral bodies, and are in immediate contact with
the intervertebral discs.
Articular processes, which are situated more posteriorly, are driven
towards one another across intervertebral joints, resulting in compression
damage to articular cartilage, microfractures [tiny fractures which are
not visible on x-rays] of bone adjacent to joints, and/or bleeding into
joints.
During hyperflexion or flexion-compression strains, the anteriorly situated
vertebral bodies and intervertebral discs are compressed from top to bottom.
These structures are usually strong enough to resist fracture or disruption
with the magnitude of forces generally applicable during whiplash neck
injuries, but intervertebral discs whose annulus fibrosis has already
been damaged by the hyperextension strain, or previously degenerate or
damaged intervertebral discs, are susceptible to further sprain, disruption,
or bulging of the annulus fibrosis.
During hyperflexion strains, posteriorly situated muscles and joint capsules
are sprained. Disruption of posteriorly situated soft tissues is uncommon
in view of the protection afforded by the chin abutting on the chest during
hyperflexion strains.
COMPLICATIONS
The pathological entities referred to above represent the types of tissue
damage encountered in common or uncomplicated whiplash neck injuries.
When more severe or complex forces are applied, however, and also in
cases of more significant pre-existing cervical spinal pathology, the
whiplash neck injury may be complicated by additional and more severe
forms of injury.
These complications may include : -
· Vertebral fractures with or without significant displacement
of bony fragments.
· Severe disruption of ligaments resulting in dislocation or subluxation
of adjacent vertebrae, in which case the normal alignment of the spinal
column is lost.
· Intervertebral disc herniation, with protrusion of disc material
into the spinal canal or intervertebral foramina.
· Neurological injury to the spinal cord, segmental nerve roots,
or brachial plexus.
Many of these complicated cases are unstable [the structures of the spine
do not have sufficient integrity or strength to withstand normal physiological
loads] and may require surgical intervention to prevent further damage.
SYMPTOMS
Neck pain
Patients with whiplash neck injury typically experience neck pain. The
onset of neck pain may be immediate, but pain usually commences within
the first few hours of the accident. The pain is typically:
· worse on waking the morning after the accident,
· perceived over the back of the neck,
· dull or aching in quality,
· or may have a sharp stabbing component, which is usually associated
with movement.
Other neck symptoms
Patients typically complain of various types of neck discomfort, including
a feeling of stiffness, a feeling of tension or pulling, and/or muscle
spasms, and most commonly of a restriction of neck movements.
Headaches
Headaches are commonly experienced at the back of the head or the junction
between the head and the neck, and often also radiate forwards into the
temples and behind or above the eyes.
Inter-scapular symptoms
In some cases pain and discomfort extends from the neck downwards into
the inter-scapular region [between the shoulder blades], of the thoracic
spine [upper back].
Shoulder-arm symptoms
In some cases pain and discomfort, as well as paraesthesiae [a feeling
of pins and needles] and/or numbness is experienced in the shoulders and
less commonly in the upper limbs.
Other symptoms
Patients with whiplash neck injury may experience a variety of other
symptoms, which occur less commonly. These other symptoms, which are not
discussed in this paper, may be the result of more severe injury and/or
complications, and should prompt careful assessment by a spinal specialist
[a neurosurgeon or an orthopaedic surgeon with an interest in spinal conditions].
MANAGEMENT OF WHIPLASH NECK INJURIES
Diagnosis
As with any medical condition or injury, the first and most important
aspect of management is to obtain an accurate diagnosis. Most cases of
whiplash neck injury are attended to and treated by casualty medical officers
or general practitioners.
The doctor will obtain a history of the circumstances and nature of the
accident as well as the symptoms experienced by the patient, after which
the doctor will conduct a physical examination, and then refer the patient
for x-rays or other investigations as may be necessary.
On physical examination the doctor will typically find a restricted range
of neck movements and an increased state of contraction of neck muscles.
Tissues of the neck are also commonly tender to touch. The most important
aspects of the physical examination are to identify or exclude the presence
of neurological dysfunction and/or instability.
X-rays of the neck generally show no abnormalities, which is understandable
as x-rays essentially "see" bones and not soft tissues. Sometimes
x-rays will show abnormal straightening or curvature of the neck secondary
to muscle spasm, but these findings are often nonspecific and may be difficult
to distinguish from normal. The most important reason for neck x-rays
is to identify or exclude significant pre-existing pathological conditions
on the one hand, and to identify or exclude complications such as the
fractures, ligament disruptions, and subluxations on the other.
Treatment
If complications are present the attending doctor will usually refer
the patient to a spinal specialist. The treatment of complications does
not form part of the subject matter of this paper.
The standard treatment of whiplash neck injuries is conservative [nonsurgical],
and is mainly directed at relieving pain and discomfort on the one hand,
and protecting the spine from further harm while natural healing occurs
on the other.
If one considers the nature of the tissue damage, as described above,
it is evident that no treatment intervention is capable of reversing or
repairing the damage, or of curing the condition.
Treatment typically includes prescription of anti-inflammatory, analgesic
[painkillers], and muscle relaxant medications, advice about personal
neck care and protection, and short-term protection of the neck in a soft
collar, followed at some stage by physiotherapy.
Because of the inability to repair the damage or cure the condition,
all treatment modalities are in fact "supportive" as opposed
to "therapeutic".
It is hardly surprising, therefore, that controversies exist. So, for
example, some practitioners will advise prolonged immobilization in a
rigid or semirigid collar, while others will never advise the use of a
collar. Some practitioners emphasize exercise and movement, while others
emphasize rest.
None of these firm beliefs are entirely right or entirely wrong, as each
of the concepts of management has advantages and disadvantages.
Movement of the neck is physiological and is necessary for normal health
of soft tissues, particularly joints and muscles. On the other hand movement
of the neck pulls or strains damaged soft tissue fibers, thereby interfering
with natural healing, or causing more pain and even further harm.
Rest is a time-honoured and generally sound principle of management of
many illnesses and injuries. Rest conserves energy, allows the natural
healing processes of the body to proceed, and helps to prevent further
harm while healing progresses. On the other hand, immobilization of joints
and muscles, particularly when severe or prolonged, results in joint stiffness,
joint pain, wasting of muscles, and muscle pain. Excessive rest also results
in demineralization of bones.
Treatment of whiplash neck injuries is most effective if commenced early,
with the application of sound principles of management, and if conducted
with full and frank communication between doctor and patient.
The following rules of thumb are offered, but should be adapted to particular
cases taking cognizance of all relevant facts.
· Minor cases should not interrupt their normal day to day light
activities, and do not require collars, but strenuous activities and sports
should be avoided until the condition has recovered.
· For moderate and severe cases a short period of rest at home
or in hospital is useful. Soft neck collars are useful to protect the
neck and reduce pain and discomfort in moderate and severe cases, but
should be removed intermittently to permit small gentle movements, and
should not be used for more than a few weeks.
· Rigid and semirigid neck braces are best avoided in uncomplicated
whiplash neck injuries.
· Anti-inflammatory medications, simple analgesics, and muscle
relaxants are useful for symptomatic relief, particularly in the short
term.
· Habit-forming analgesics and other habit-forming drugs should
be avoided.
· Gentle forms of passive physiotherapy, as well as appropriate
gentle exercises, should be commenced relatively early, as soon as the
acute post-traumatic pain syndrome has started to settle.
· Vigorous forms of physiotherapy, vigorous exercise, traction,
and manipulation of the neck should be avoided.
Personal neck care and protection should be practiced from the beginning,
and should be continued in sensible measure in the long term. This concept
relates to neck and back posture, ergonomics, neck movements, and physical
activities. Patients should be instructed in the principles of spinal
care, as well as particular practical application, taking into account
their work and recreational activities. Instruction can be provided by
a medical practitioner, a spinal specialist, a physiotherapist, and/or
an occupational therapist. It is generally beneficial to obtain instruction
or advice from more than one health care professional.
In brief the principles of personal neck care and protection include
the following : -
· When the head and shoulders are not supported, erect balanced
posture should be maintained. The plumb line from the craniocervical junction
[representing the center of gravity of the head, and more or less in line
with the ears] should pass through the cervicothoracic junction of the
spine [more or less in line with the tip of the shoulders], and should
pass through the lumbosacral junction [more or less in line with the hips].
· The natural tendency to slump or stoop over a desk should be
avoided. Looking down when working at a desk should be performed by tucking
the chin in towards the chest, without moving the head [ears] forwards,
and so maintaining a balanced head on neck posture. One should remind
oneself that the eyes are also capable of looking down without bending
the back or neck forwards.
· Activities which require excessive, vigorous or frequent neck
movement [such as craning ones neck to stare upwards, driving a golf ball,
playing squash, and swimming breaststroke, crawl, or butterfly] should
be avoided.
· Activities performed with the hands should be relatively light,
and should be performed with the elbows comfortably at the sides of the
body.
· Furniture and equipment should be designed and positioned to
promote comfortable use without straining the spine.
· Strenuous physical activities, pounding or impact activities,
and contact sports should be avoided.
Although the mechanism of nonphysical factors is difficult to understand
in our concrete world, there can be no doubt that the mind of the patient
exerts a significant influence on the effectiveness of treatment.
· In this regard it is known that patients who expect to improve
are more likely to do so than those who expect to have long-term pain
and disability.
· Likewise, patients who are dismissed as "neurotics"
or "malingerers" by poorly informed health care professionals,
relatives, insurers, employers, or lawyers, simply because the nature
of their injuries cannot be identified on x-rays or physical examination,
are likely to respond poorly to treatment.
· Individuals with comorbid psychological conditions such as depression
or anxiety do less well than individuals who are well-adjusted, happy,
and positive.
· Individuals who are strongly motivated to work do better than
those who have nothing to do or who do not want to work.
· In the presence of any adverse psychological factors, as well
as any comorbid psychological condition, early and effective psychotherapy
and/or psychotropic medication may be the key to success or failure of
treatment.
COURSE AND OUTCOME
Fortunately the majority of individuals who suffer whiplash neck injuries
recover fully within weeks or months.
Because of the nature of the injury, and because of the inability of
any modality of treatment to repair the damage to soft tissue structures,
it should be understood that the term "recovery" refers to a
resolution of pain and discomfort, as well as regaining the capacity to
engage in one's normal day-to-day activities.
The concept of "cure" does not apply, as sprained or disrupted
soft tissues heal by the formation of fibrotic scar tissue. The scar tissue
which bridges and holds together the ends of damaged fibers of muscle
or ligament does not have the natural strength or elasticity of healthy
tissue.
In contrast to fractures of bone, which once healed typically recover
to normal strength, alignment, and function; sprains or disruptions of
soft tissues always result in some degree of permanent weakening and may
result in some degree of permanent lengthening of the injured soft tissue
structures.
A neck which has "recovered" from a whiplash injury may withstand
the strains and loads placed upon it for the rest of the individual's
life by the individual's normal work and recreational activities, but
it may not. Many fortunate individuals do manage to return to their previous
activities and never experience any further neck symptoms or limitations.
In these cases the recovery is equivalent to "cure".
In other less fortunate cases, where full resolution of symptoms and
apparent resolution of limitations has occurred, the resumption of previous
activities and postures leads to secondary deterioration at some later
stage in the individual's life.
Whether a "recovered" neck will remain asymptomatic and fully
functional or not can unfortunately not be predicted or guaranteed in
any given case, as the ability or failure in this regard is a function
of the degree of injury and permanent damage [not measurable by any reliable
scientific device] on the one hand, and the nature, degree and repetitiveness
of strain applied to the neck of the individual on the other.
For the above reasons it is wise to apply sensible personal neck care
and protection in the long term, even following injuries which appear
to have "recovered". In essence this concept means to : -
· apply those adaptations to posture, ergonomics, etc. which will
not impair one's productivity or prevent essential activities,
· avoid unimportant activities and positions that are known to
strain the neck, and
· spare one’s neck for the important things in life.
Unfortunately a certain number of individuals who have suffered whiplash
neck injury fail to recover, and continue to experience symptoms and functional
impairment in the long term.
In these cases, where medical science in general, or the treating health
care professionals individually, are considered to have failed the patient,
secondary psychological sequelae are inevitable.
It is often not possible to identify particular reasons why a particular
individual has failed to recover, except in the case of severe or complicated
injuries where permanent problems are more likely.
Chronic symptoms and functional impairment typically result in a reduction
or cessation of sporting, recreational, and other nonessential activities.
In a smaller number of chronic sufferers the complex syndrome results
in a degree of occupational disability, usually by way of a reduction
in productivity, and sometimes even in premature retirement from work.
Although no treatment is capable of solving the problem, various modalities
of treatment do provide temporary symptomatic relief and improved functional
capacity. For this reason these individuals often make use of chronic
supportive treatment, which is best coordinated under the periodic supervision
of a spinal specialist. Other forms of therapy, such as Pilates, hydrotherapy,
biokinetics, acupuncture, relaxation training, and hypnotherapy may be
useful in chronic cases.
Individuals with chronic symptoms and functional impairment should be
monitored by a spinal specialist from time to time in order to detect
late complications or deterioration, which may require specific or more
intensive treatment.
SOCIETAL IMPACT OF WHIPLASH NECK INJURY
It is an unfortunate reality that because of the very large numbers of
motor car accidents, the relatively small proportion of whiplash victims
who go on to suffer long-term symptoms and functional impairment constitutes
a sizable population of long term sufferers.
These long term victims suffer long term damages by way of medical and
other treatment costs, pain and suffering, loss of amenities and enjoyment
of life, occupational disability, and loss of earning capacity.
Because of the numbers of such victims, the economic impact on society,
and more particularly on the insurance industry, is considerable.
It is little wonder that long-term victims of whiplash neck injury make
up a sizable proportion of those who lodge claims for compensation against
the Road Accident Fund.
Because of the "hidden" nature of the injury and disability,
because of the typical absence of neurological deficits [e.g. paralysis
or loss of sensation], instability, and clear radiological abnormalities,
and because of the perceived ease with which dishonest claimants can exaggerate
or fabricate their complaints, there is a measure of skepticism in the
insurance industry, as well as in the legal profession and the medical
profession. It is therefore common for whiplash claimants to be viewed
as neurotic or malingering.
It is certainly possible for dishonest individuals to claim that they
suffer from severe and disabling headaches, neck pain, and other symptoms
when in fact they do not, and all or most spinal specialists have come
across such individuals. It is, however, now known that the majority of
individuals who complain of chronic symptoms and functional impairment
are in fact genuine, and that their complaints are the result of incurable
organic pathology [physical damage to tissues].
To a large extent the complex and lengthy medicolegal process has evolved
to identify and exclude dishonest malingerers from compensation, and to
facilitate just and appropriate compensation for genuine victims.
Potential malingerers or false claimants are strongly advised against
this reprehensible practice, as the medical, legal, and allied professions
have well developed methods of identifying malingerers and false claimants,
and rightly have no sympathy for those who attempt to abuse a system designed
to compensate those in genuine need
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