WHIPLASH NECK INJURY

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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