The term whiplash injury is used for a neck injury caused by a sudden movement of the head forwards, backwards or sideways.
The injury is also called Whiplash Associated Disorders. An acute whiplash injury follows sudden or excessive hyperextension, hyperflexion, or rotation of the neck and causes neck pain and other symptoms. Whiplash injury is common in road traffic accidents, and may also be caused by sports injuries, falls or assaults. Most cases of whiplash injury occur as the result of rear-end vehicle collisions.
Most of the injuries happen in C5 and C6 cervical vertebrae.
A whiplash injury from an automobile accident is called a cervical acceleration-deceleration injury. Whiplash associated disorders sometimes include injury to the brain.
The most common areas of the spine affected by whiplash are the neck and middle of the spine. Rear end collision in a motor vehicle is common cause of whiplash injury. Injury might also occur in kinematics may be roller coaster rides at an amusement park, skiing accidents, airplane travel, or simply from being hit, kicked or shaken.
Rates of whiplash are higher in persons using a seat belt with shoulder restraint [than with no restraint], poor posture and poorly-fitted head restraints.
Whiplash injury is more common in women than men.
Mechanism of Whiplash Injury
The exact mechanism of whiplash injury is not known. Impulsive stretching of the spine, mainly anterior longitudinal ligament stretching or tear, as the head snaps forward and then back again causing a whiplash injury is thought to be the cause.
Injury can occur in two ways –
Cervical hyperextension injuries occur when an injury occurs by hyperextension of the neck followed by flexion. This occurs when persons sitting in the stationary or slow-moving vehicle being struck from behind. The person’s body is thrown forward but the head lags, resulting in hyperextension of the neck. When the head and neck have reached maximum extension, the neck then snaps into flexion.
A rapid deceleration injury occurs when the force flexes the neck followed by hyperextension. When the head is thrown forward, it flexes the cervical spine. The chin limits forward flexion but the forward movement may be sufficient to cause longitudinal distraction and neurological damage. Hyperextension may occur in the subsequent recoil.
Classification of Whiplash Injuries
Whiplash-associated disorders can be classified by the severity of signs and symptoms
- Grade 0: no complaints or physical signs.
- Grade 1: indicates neck complaints but no physical signs.
- Grade 2: indicates neck complaints and musculoskeletal signs.
- Grade 3: neck complaints and neurological signs.
- Grade 4: neck complaints and fracture/dislocation
- Most cervical spine fractures occur predominantly at two levels – at the level of C2 or at C6 or C7.
- Most fatal cervical spine injuries occur in upper cervical levels, either at the cranio-cervical junction C1 or at C2.
Presentation of Whiplash Injuries
The pain and other symptoms of a whiplash injury may not develop until 6-12 hours or even after a few days.
The symptoms may include
- Pain in neck and jaw with or without a decrease in the range of movements
- Tightness in paraspinal muscles muscle tightness and spasm
- Interscapular pain, shoulder pain
- Reduced range of movements and neck tenderness
- A headache, dizziness, vertigo, blurring of vision.
- Numbness, weakness, paraesthesia, sphincter disturbance and increase in reflexes in upper limbs and lower limbs in cases of cord injury
- Retropharyngeal [behind the pharynx] swelling and difficulty in swallowing.
- Insomnia, anxiety (general anxiety and/or travel anxiety when in a car) or depression.
The examination should be done to look for parts injured, ascertain the level of spinal injury and any associated injury like a head injury.
For all patients presenting with acute whiplash injury, spinal cord compression should be excluded. Risk factors for serious injury include a history of neck surgery presence of osteoporosis or risk factors for osteoporosis like premature menopause, use of systemic steroids etc.
Neurological deficit is rare in soft-tissue injuries associated with whiplash. Stretching of the esophagus with resulting edema, dysphagia, and retropharyngeal hemorrhage may occur. Vocal-cord damage with hoarseness has been reported.
Trauma to the cervical sympathetic chain may occur with symptoms of nausea, vomiting, dizziness, Horner’s syndrome, and even complex regional pain syndrome type I.
Persistent radicular pain after cervical trauma requires further investigation to rule out nerve root involvement.
It is essential to consider serious injury in the immediate period following injury. Other possible causes of acute neck pain and stiffness include vertebral fractures, cervical disc herniation, subarachnoid hemorrhage, meningitis.
Persistent neck pain and stiffness also occurs in cervical spondylosis and other chronic pathologies of the cervical spine.
List of causes of neck pain
Laboratory investigations are mostly normal in whiplash injury patients
Anteroposterior, lateral and anteroposterior odontoid peg views are standard x-ray projections done for whiplash injury.
Guidelines for selecting a patient for radiography – Canadian C-spine rule
CT is superior to plain radiography and is indicated immediately if:
- The patient had a Glasgow coma scale <13
- The patient has been intubated or is being scanned for multi-region trauma.
CT is also done in cases where x-rays are suspicious or abnormal or are normal in presence of strong clinical suspicion.
CT is also done in cases of children<10 years as odontoid view x-ray is not done in these cases.
MRI is better for detecting soft tissue injuries such as an intervertebral disc, posterior longitudinal ligament, and interspinous ligament injury etc.
MRI should be done in patients with indicated for patients with neurological even in presence of normal radiographs.
MRI can distinguish hematoma from edema, which can have prognostic importance.
Not routinely done. This is indicated if MRI is not available or contraindicated or patient is not able to tolerate MRI
Treatment of Whiplash Injuries
The course of minor injuries is usually self-limited and can be managed by analgesic drugs, neck support like the cervical collar and local cold/heat therapy.
Other treatments, like ultrasound and massage and exercises, may also help.
Most cases resolve in a few days. But other neck strains may take weeks or longer to heal.
Overall treatment modalities for whiplash injury involve
Soft cervical collar
- Bed rest
- Gradually increased activity for the first 1 to 2 weeks.
- Isometric exercises, heat, traction
- Transcutaneous-electrical nerve stimulation
- Nerve block with local anesthetic and/or steroids.
Surgical treatment may be required in serious injuries.
The consequences of whiplash range from mild pain for a few days to severe disability.
Following factors may indicate long-term chronicity and disability
- A negative attitude
- Fear avoidance behavior
- Reduced activity
- Not willing to participate in active movement regimen
- Depression, low morale and social withdrawal.
- Social or financial problems.