Whiplash Injury

Written by Dr David Shepherd MBBS | Senior Accredited Orthopaedic Registrar

Video

Definition

  • The term whiplash encompasses an indirect injury to the cervical spine other than fracture.
  • Patients who have sustained low-velocity injuries often describe more pain than those who have had a fracture.
  • They can show disproportionate psychological distress.
  • Patients can
    • Give a consistent account of their injury
    • Exaggerate their symptoms – which leads to suspicion that they are doing so for gain.

Aetiology

  • Effect of differential velocity on the head and upper torso
  • Change of velocity of 2.5 mph is sufficient to cause symptoms
  • The trunk is forced backwards and ramps up the back of the seat, the neck hyperextends and then recoils forward.
  • Rear end collision
    • most common mechanism
    • 50% of case
    • associated with more severe symptoms than collisions from other directions
    • increased displacement of the neck heavier vehicle
  • Females 2 : Male 1
    • neck is thinner
    • less rigid.

Car features

  • Low neck rest
    • acts as a fulcrum
    • head pivots with greater amplitude than if no neck rest was present at all.
  • Strategies in car design to reduce Whiplash
    • more elastic seat back
    • high head rest
      • reduces posterior excursion of the head
      • 50% less claims

Epidemiology

  • Constitutional neck pain and whiplash injury
    • Neck pain is common
      • 43% of Swedish, 34.5% of Norwegian and 40% of British patients at some time.
    • Chronic symptoms which have lasted for more than 3 to 6 months
      • 19% of Swedish, 14% of Norwegian, 14% of British patients
    • Chronic neck pain in European population studies
      • 5 times more likely in patients with whiplash injuries than in matched population cohorts
  • Early presentations to an Emergency Department
    • 37% described the onset of pain as immediate
    • 62% to 65% within 12 hours
    • 90% within 24 hours.
    • Account for the more symptomatic one-third of patients

Anatomy

Pathology

Classification

GroupDescription
1~ symptoms related to their injuries
~ no abnormality on physical examination.
2~ symptoms
~ reduced range of movement of the cervical spine but no abnormal neurological signs.
3~ symptoms
~ reduced range of cervical movement
~ evidence of objective neurological loss.
Norris & Watt Presentation Classification of Whiplash
Group% Description
A12~ free of any discomfort
~ complete recovery from their accident.
B48~ left with mild symptoms
~ which did not interfere with their work or leisure activities.
C28~ complained of intrusive symptoms which handicapped work and leisure
~ caused them to seek relief by frequent intermittent use of analgesia, orthoses or physiotherapy.
D12~ suffered from severe problems, had lost their jobs, relied continually on orthoses or analgesics
Gargan & Bannister Outcome Classification of Whiplash

History

  • Pain
    • neck pain
    • thoracolumbar back pain
    • upper limb pain and weakness
      • 50% of upper limb pain and weakness occur more than a week after the injury
  • stiffness,
  • occipital headache,
  • paraesthesia of the upper limb
  • irritation of the brachial plexus
    • 38%

Examination

  • less prognostic than symptoms,
    • neck tenderness,
    • Stiffness,
    • neurological deficit
  • rarely conforms to myotomes or dermatomes
  • impaired reflexes may be the result of pain inhibition.

Investigations

  • Xray
    • Cervical spondylosis at C5-6
      • 2x as many symptomatic as in asymptomatic patients
    • Preaccident Spondylotic
      • incidence of pain of 53% after two years
    • Radiological progression
      • Patients who sustain a whiplash injury in their third decade and undergo radiography ten years later show a level of cervical spondylosis which is typical of necks 15 years older.
  • MRI
    • no difference in the rate of disc degeneration on MRI
      • Controlled studies of symptomatic and asymptomatic patients have shown
    • Abnormalities on MRI are not generally seen after a whiplash injury.
    • When to perform MRI
      • MRI should only be carried out after a whiplash injury if there is nerve-root pain in the arm which may potentially be relieved by discectomy
  • Xray changes -Norris and Watt
    • Normal xrays
      • 30 % Group 1
      • 2.5 % Group 2
      • 100% xrays in Group 3 were abnormal.
    • Degenerative spondylosis was detected
      • 26 % Group 1
      • 33 % Group 2
      • 40 % Group 3.

Differential Diagnosis

Treatment

  • Acute whiplash injury
    • NO soft cervical collar
      • less effective than normal activity and physiotherapy
    • ? Physiotherpapy
      • The routine prescription of physiotherapy does not help most patients who recover spontaneously.
  • Late whiplash injury
    • ? facet blocks
      • result in a rate of recurrence of 50% within a week
    • ? radiofrequency neurotomy of the facet joints
      • result return of pain of 50% after nine months
    • Cervical fusion after a whiplash injury
      • may be indicated for brachialgia
      • successful in 32% of patients.

Summary

  • Risk factors for long term symptoms
    • Strong
      • early onset of neck pain,
      • severe neck pain,
      • adverse psychological response
      • neck stiffness
    • Weak
      • radiating pain
      • neck tenderness
  • Prediction of Recovery
    • Predictable at 3 months
      • can be predicted with a high level of probability at three months.
      • Most patients who are symptomatic after three months remain so indefinitely
  • Role of rehabiliation
    • little evidence that rehabilitation programmes significantly improve the outcome of late whiplash injury.

Complications

Prognosis

  • Lack of a uniform outcome measures.
  • Worse outcome factors
    • The longer the symptoms last, the worse is the prognosis.
    • Pre-morbid psychological disease
    • radiation of symptoms
  • Using the scoring system of Gargan and Bannister
    • Outcome after two years can be predicted in over 70% of cases after three months.
      • 66% make a full recovery
      • 2 % permanently disabled.
    • The worse the initial whiplash-associated disorder grade is,
      • the worse is the long-term outcome,
      • particularly if there is associated neck stiffness
    • if patient is asymptomatic at:
      • 2 months
        • 88% are asymptomatic after two years.
      • 3 months
        • 93% after three months remain asymptomatic after two years.
    • Improvement is minimal after the first year.
  • Symptoms associated with a worse outcome
    • rapid onset of pain,
    • severity of neck pain,
    • acute hospital admission,
    • radiation of pain to the upper limb and headache.
  • Signs associated with a worse outcome
    • neurological deficit,
    • neck stiffness
    • neck tenderness
  • Psychological outcome
    • Types
      • impaired concentration,
      • somatoform disorder,
      • forgetfulness,
      • post-traumatic stress disorder
      • driving anxiety
    • Development
      • The greater the pain is, the worse is the psychological response.
        • As the pain persists patients develop psychological sequelae.
          • Depressive symptoms become apparent after six weeks.
          • Mood disorder after one year is twice that expected in the general population
        • The psychological response after a whiplash injury is as marked as that after multiple fractures
    • Outcome worse if associated
      • with pre-morbid psychiatric disease
      • responsibility for dependents
    • Driving anxiety
      • 4% of patients are unable to drive after three months,
      • 100% are able to drive after 12 months.
  • Other associations with a worse outcome
    • Older age,
    • lower educational achievement,
    • part-time employment,
    • pre-existing neck
    • low back pain
    • previous whiplash injury
    • Above average rate of attendance to general practitioners for unrelated conditions.
  • Litigation
    • The view that a claimants’ symptoms will improve once litigation has settled is unsupported by the literature.
    • Continuing litigation is associated with more severe pain and continuing symptoms.
    • However, larger settlements are awarded to more severely affected patients, and these take longer to conclude.
    • Litigation – Norris and Watt
      • Group 1
        • patients who pursued claims were either improved after the claim had been settled, were no worse.
        • Patients with mild initial symptoms are less likely to make a claim.
          • If they do make a claim 50 per cent are still likely to continue to improve.
      • Group 3
        • there were only two patients who felt improvement in their overall symptoms after settlement.
        • less likely to maintain any improvement, and indeed some deteriorated after settlement of their claims.
        • Suggest that litigation has little influence on symptoms.
  • Cultural differences
    • Road-traffic accidents over one year in New Zealand compared with those Victoria.
    • With a similar size of population and number of cars,
    • Victoria
      • 3.5 times as many rear-end collisions reported in Victoria
      • 10 times as many patients claimed compensation
      • 5 times as many were off work for more than two months.
    • Why the difference?
      • New Zealand operated a no-fault compensation system and Victoria a tort scheme.
      • In 1987 legislation was introduced in Victoria which required patients to report all whiplash injuries to the police and to pay the first $ 317 of their medical expenses.
        • Claims fell by 68%.
      • However, it was subsequently recorded that 10% of Australians who sustained whiplash injuries continued to have chronic neck pain after the legislation.
    • Norway
      • neurologists found little difference in neck pain between car occupants involved in a motor-vehicle accident in Norway and a general population cohort group in Lithuania where whiplash injury is not recognised.

References

  • G. Bannister, R. Amirfeyz, S. Kelley, M. Gargan. Whiplash Injury. JBJS [Br] 2009;91-B:845-50.
  • S. H. NORRIS, I. WATT. THE PROGNOSIS OF NECK INJURIES RESULTING FROM REAR-END VEHICLE COLLISIONS. JBJS (Br) VOL. 65-B, No. 5, NOVEMBER 1983
  • M. F. GARGAN, G. C. BANNISTER. LONG-TERM PROGNOSIS OF SOFT-TISSUE INJURIES OF THE NECK. JBJS (Br) VOL. 72-B, No. 5, SEPTEMBER 1990