Epidemiology

• Trauma and sports injuries are more common in young adults.
• Rates of whiplash are higher in persons using a seatbelt with shoulder restraint than with no restraint, but seatbelts often prevent more serious injuries.
• Poor posture.
• Poorly-fitted head restraints.
• Women sustain higher rates of whiplash, probably because their neck muscles are less well developed than men's.
• Narrowing of the cervical spinal canal due to acquired or congenital disorders predisposes to spinal cord damage with these types of injuries.

Risk factors for severe injury

The Canadian cervical spine rule for risk of skeletal injury^[6][7][8]:

• The Canadian cervical spine rule applies to trauma patients who are alert (Glasgow coma scale of 15) and stable.
• It has been shown to be safe and reliable, missing only one unstable injury in a series of over 16,000 cases.

High risk factors

• Age 65 years or over.
• Paraesthesia in extremities.
• Dangerous mechanism of injury, which is considered to be:
  • A fall from a height of at least a metre or five stairs.
  • An axial load to the head, eg during diving.
  • A motor vehicle collision at high speed (>100 km/h) or with rollover or ejection.
  • A collision involving a motorised recreational vehicle.
  • A bicycle collision.

Low risk factors

• Simple rear end motor vehicle collision (excludes being pushed into oncoming traffic, being hit by a bus or a large truck, a rollover, and being hit by a high speed vehicle).
• Able to sit rather than lie down in the emergency department.
• Ambulatory at any time.
• Delayed (not immediate) onset of neck pain.
• Absence of midline cervical spine tenderness.

Presentation

See also the separate article on Examination of the Spine.

The clinical symptoms of whiplash injury may not develop until 6-12 hours after the injury, or even after a few days. These include:

• Neck pain, jaw pain, paraspinal muscle tightness and spasm. Neck pain usually develops shortly after the accident and may worsen and peak 1-2 days after the event.
• Interscapular and low back pain.
• Reduced range of movements and neck tenderness.
• Headache, dizziness, vertigo, blurring of vision.
• Numbness in shoulders and arms. Paraesthesia and weakness in the arms and legs - depending on presence and site of any cord contusion.
• There may be retropharyngeal swelling and dysphagia.
• Insomnia, anxiety (general anxiety and/or travel anxiety when in a car) or depression.
• Leg weakness, hyperactive tendon reflexes in the legs, upgoing plantar response, and/or sphincter disturbance, suggests damage to the spinal cord.
• Arm weakness or numbness suggests injury or entrapment to the nerve roots of the cervical spine.
• Symptoms may be severe, but investigations often do not demonstrate any abnormality.

Differential diagnosis

It is essential to consider serious injury in the immediate period following injury. Other possible causes of acute neck pain and stiffness include:

• Spinal fracture.
• Cervical disc herniation.
• Subarachnoid haemorrhage (may precede or occur at time of a road traffic accident).
• Meningitis or meningism due to systemic infection.

It is also essential to consider other causes of symptoms, eg a person in a road traffic accident may have severe chest pain due to restraint from seatbelt, but the possibility of acute myocardial infarction, especially in the elderly, must be considered.

• If the neck symptoms persist then it is also very important to consider other causes of chronic neck pain, even though soft tissue 'whiplash' injuries may cause long-term symptoms. One study found the prevalence of persisting pain after whiplash injuries to be very similar to the prevalence of chronic neck pain in the general population.^[9]
• Other possible causes of persistent neck pain and stiffness include:
  • Cervical spondylosis: results from narrowing of the canal around the spinal cord, with or without the formation of bony osteophytes
  • Tumours: brain tumours, bone tumours

Investigations

NICE recommends using an adapted version of the Canadian cervical spine rules that incorporates some aspects of the NEXUS rule to identify patients who need imaging of the cervical spine.^[10]

• Cervical spine X-rays:
  A standard series of X-rays of the cervical spine consists of three views: anteroposterior, lateral and anteroposterior odontoid peg views. The lateral view must show the top of the T1 vertebral body, and the odontoid peg view should show the lateral masses of the atlanto-axial articulation. In children aged <10, use anterior/posterior and lateral radiographs without an anterior/posterior peg view, and use CT imaging to clarify abnormalities or uncertainties.
  The following patients should have plain radiography (three views) of the cervical spine:^[11]
  • Patients with neck pain or midline tenderness if aged ≥65 years, or any age if there was a dangerous mechanism of injury (see above).
  • Patients where a definitive diagnosis of cervical spine injury is needed urgently (eg before surgery).
  • Any patients where it is considered unsafe to assess movement.
    Safe assessment can be carried out if the patient:

    • Was involved in a simple rear end motor vehicle collision.
    • Is comfortable in a sitting position in the emergency department.
    • Has been ambulatory at any time since injury with no midline cervical spine tenderness.
    • Has delayed onset of neck pain.
  • Patients initially considered safe to assess movement in the neck still need cervical spine X-rays if on assessment they cannot actively rotate the neck 45° to the left and right.
• CT scanning of cervical spine:^[10][11]
  • CT scan is indicated immediately if:
    • Patient had a Glasgow coma scale (GCS) <13 on initial assessment.
    • Patient has been intubated, or is being scanned for multi-region trauma.
  • CT is also indicated:
    • If plain films are deemed inadequate, suspicious, or definitely abnormal.
    • If clinical suspicion of injury continues despite a normal radiograph.
  Computed tomography is superior to plain radiography, with a reported sensitivity of 100% and specificity of 99%.
• MRI scanning of cervical spine:
  • The technique depicts soft tissue structures well, with reported sensitivities for intervertebral disc injury of 93%, posterior longitudinal ligament injury of 93%, and interspinous ligament injury of 100%.^[10]
  • MRI is indicated for patients with neurological signs, even if plain films are negative.
  • MRI can distinguish haematoma from oedema, which can have prognostic importance.
• CT myelography:
  • Indicated if MRI is not available
  • If the patient cannot tolerate MRI
  • If MRI is contraindicated.

Management

For serious neck injuries, see also the separate article on Spinal Cord Injury and Compression. Provide the following advice and reassurance for the majority of patients who have not suffered a severe injury:^[1]

• Provide reassurance that whiplash-associated disorder is usually benign and self limiting.
• Encourage early return to usual activities and early mobilisation. Explain that usual activities may initially be painful, but this is not harmful or indicative of ongoing damage.
• Discourage rest, immobilisation, and the use of soft collars.

For patients with acute whiplash, there has been a trend towards active treatments to reduce pain and stiffness but the evidence remains conflicting. There is insufficient evidence to indicate the most effective treatments for patients with whiplash-related problems that has lasted for longer than six months.^[12] A Cochrane review by Peloso et al found:^[13]

• Intramuscular injection of lidocaine for chronic mechanical neck disorders (MND) and intravenous injection of methylprednisolone for acute whiplash are effective treatments.
• There is limited evidence of effectiveness of epidural injection of methylprednisolone and lidocaine for chronic MND with radicular findings.
• Other medications, including NSAIDs and muscle relaxants have contradictory or limited evidence of effectiveness.
• There is moderate evidence that Botox-A intramuscular injections for chronic MND are not better than saline.

However the following are considered to be appropriate management:

• Recovery and return to full function is best aided by sympathy and encouraging the patient to take an active role in dealing with the symptoms.
• Provision of adequate analgesia.
• There is now good evidence that the use of collars in whiplash injury prolongs the recovery of the patient. Patients should be advised about neck mobilisation and encouraged to remain as active as possible.^[14] Patients should receive instruction about exercises.^[15]
• Physical therapy:
  • A recent study comparing education by GPs compared to physiotherapists found no significant differences in overall outcome and treatments by GPs and physiotherapists were of similar effectiveness.^[16]
    • The long-term effects of GP care seemed to be better compared to physiotherapy for functional recovery, coping, and physical functioning.
    • Physiotherapy was found to be more effective than GP care on cervical range of motion at short-term follow-up.
  • Patients with particularly severe symptoms or symptoms that are not resolving may benefit from referral to physiotherapy but physiotherapy treatment is most effective if started soon after the injury occurs.
  • Manipulation plus exercise has been shown to have short-term and long-term benefits for subacute and chronic MND with or without headache.^[17]
  • There is some evidence that acupuncture treatment in patients with chronic neck pain is associated with improvements in neck pain and disability.^[18]
• When 'yellow flags' (indicators of psychosocial barriers to recovery) are identified, early intervention is important and may include:^[1]
  • Simple education and reassurance to correct erroneous beliefs.
  • Referral for a short course of cognitive behavioural therapy.
  • Referral to a psychologist or pain clinic.
• Surgery may be required for a fracture or spinal cord injury.

Complications

• May cause variable difficulties and restrictions with employment, leisure activities, domestic and personal care.
• This may lead to financial as well as psychological difficulties.

Prognosis

The prognosis of whiplash injury is variable and obviously depends on the severity and grade of the whiplash injury. There is great debate as to the expected prognosis which is only further confused by possible influence of compensation-seeking behaviour. Many studies have only included small numbers of affected people and have had basic flaws with study design and have only served to increase debate. A recent review found that of all patients suffering a whiplash injury as a result of a road traffic accident, over 66% make a full recovery and 2% are permanently disabled.^[2]

• In 1995 the Quebec Task Force found that:^[4]
  • 50% returned to usual activity by 31 days
  • 26% are off work between 2 and 6 months
  • 12% remain off work 6 months after injury
  • 2% remain off work over 1 year
  • 15% with multiple injuries are off work after 6 months
• Suissa et al found the following to be independently associated with a slower recovery from whiplash injuries:^[19]
  • Female gender
  • Older age
  • Neck pain on palpation
  • Muscle pain
  • Pain or numbness radiating from the neck to arms, hands or shoulders
  • Headache

Some studies have shown that the strongest prognostic indicators are factors that are present before impact. Lankester et al found that the factors that showed significant association with poor outcome on both physical and psychological outcome scales were pre-injury back pain, high frequency of General Practitioner attendance, evidence of pre-injury depression or anxiety symptoms, front position in the vehicle and pain radiating away from the neck after injury.^[20]

Prevention

• Prevention of accidents: personal responsibility when driving, safe roads, avoiding alcohol before driving.
• Properly fitted headrests play a major role in preventing or reducing the severity of whiplash injuries.
• Laser-initiated braking systems can prevent collisions and intelligent seat design can halve the rate of neck injury if an accident occurs.^[2]
• Prevention of sports injuries, particularly contact sports.
• Prevention of falls in the elderly.