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Whiplash claims cost the country about £2billion every year and motorists collectively pay about £1billion more than they need to because of high levels of claim. Britain has been described by some as the whiplash capital of Europe, with 80 per cent of personal injury claims following a road accident involving whiplash – compared to just three per cent for France.
What is Whiplash? Whiplash is a mechanism of injury, consisting of acceleration-deceleration forces to the neck. The ‘Whiplash’ event usually lasts less than half of a second. In 1995, the Quebec Task Force on Whiplash Associated Disorders (WAD) coined the term ‘WAD’ to describe the symptom sequelae of this injury. This cluster of symptoms includes neck pain, along with other symptoms of the injury such as dizziness and pain in other parts of the body. Although the resulting pathology from WAD is not clearly established, WAD is thought to result from cervical sprain or strain, probably from soft tissue damage to ligaments and muscles in the neck.There is no generally accepted objective test for a whiplash injury or ‘pain’ in general. Pain is a personal experience.
The ‘course’ of recovery from WAD refers to 2 key questions: Are neck pain and associated symptoms likely to resolve, and, if so, within what time frame? These questions are of vital interest to all stakeholders, including individuals with WAD and their families, their health care providers, those who develop and implement policy and regulations, and researchers who study WAD.
A plethora of widely varying evidence and opinion exists on these issues, resulting in a certain amount of confusion. This makes it imperative to conduct a considered and thorough examination of the existing scientific evidence and also look at the strength of that evidence. Most of the available evidence can be described, at best, as moderate in quality simply because there are too many variables to predict one outcome.
The preponderance of evidence indicates that, in adults, recovery of WAD is prolonged, with approximately half of those affected reporting neck pain symptoms 1 year after the injury. However, some studies indicate more rapid recovery, a study of Lithuanian traffic injuries reported the maximum duration of neck pain was 17 days, a study of Greek traffic injuries in which almost 90% of subjects had recovered by 1 month and 99% had recovered by 6 months and a Swedish study reporting that 52% of WAD injuries had resolved by 6 weeks. Similarly, a study of WAD insurance claims in 1987 in the Canadian province of Quebec reported that 50% of WAD claims had been closed within 1 month and that 87% had been closed within 6 months, however, the same authors reported much slower claim closure in a subsequent study which found that 40% to 50% of claims were still open 1 year post injury. Neither the rapid recovery reported in some studies, nor the prolonged recovery reported in other studies is well understood. Differences in culture, beliefs and attitudes are an interesting potential explanation.
Most studies quote complete recovery rates of around 60%, with less than 5% affected by severe chronic pain. Researchers argue that chronic whiplash pain may not be a ‘new’ pain. The best evidence suggests that 20% and 40% of the general population has experienced neck pain during the previous month, and it is possible that some of the symptoms attributed to the whiplash injury simply reflect the background prevalence of neck pain one would expect in the local general population.
Several systematic studies have tried to investigate factors that could affect the prognosis of WAD, however there is insufficient evidence to make firm conclusions on many potential prognostic variables. The best available evidence suggests that recovery is slower in those with greater initial symptom severity. Interestingly, collision-specific factors including position in the vehicle, whether the head was turned or straight ahead, awareness of the impending collision, use and type of headrest, direction of the collision are not prognostic for recovery in WAD. A summary of the literature on crash tests on human subjects concluded that a change of velocity of 2.5 mph was sufficient to cause symptoms and that a speed of 8.7 mph was needed to cause damage to a vehicle. Psychological factors such as post injury psychological distress and passive types of coping were prognostic of poorer recovery. There is evidence that compensation or legal factors are associated with recovery. There is also consistent evidence that, on average, frequent, early health care use was associated with poorer recovery. Existing evidence suggests that a past history of ‘other’ musculoskeletal disorders (other than neck, shoulder, headache or low back pain) is a risk factor for prolonged recovery; that older age may prolong recovery from non- specific neck pain; and that regular physical activity has no clear effect on outcome.
Evidence exists to support an understanding of some manifestations of WAD as a neuropathic pain condition, or as a consequence of some change at the level of central processing of pain. Evidence also exists, and continues to build, for the role of acute post-traumatic stress reactions as a predictor of poor outcome, and the relationship of such reactions with objective signs dysfunction.
Amongst those at high risk of poor recovery, attempts to prevent transition from the acute to the chronic stage of the condition or reverse chronicity once established are largely unsuccessful. Existing evidence provides moderate confidence in their prognostic ability, but more research with consistent predictors, duration of follow-up and outcomes is required for firm conclusions. Claimant’s physiological and psychological stress response remains a key driver in persistent symptoms following whiplash injury.
References:
Hogg-Johnson S, van der Velde G, Carroll LJ, et al. The burden and determinants of neck pain in the general population. Results of the Bone and Joint Decade 2000–2010 Task Force on Neck Pain and Its Associated Disorders. Spine 2008;33(Suppl):S39 –S51.`
Obelieniene D, Schrader H, Bovim G, et al. Pain after whiplash: a prospective controlled inception cohort study. J Neurol Neurosurg Psychiatry 1999;66:279–83.
Partheni M, Constantoyannis C, Ferrari R, et al. A prospective cohort study of the outcome of acute whiplash injury in Greece. Clin Exp Rheumatol 2000;18:67–70.
Suissa S, Giroux M, Gervais M, et al. Assessing a whiplash management model: a population-based non-randomized intervention study. J Rheumatol 2006;33:581–7.
Miettinen T, Airaksinen O, Lindgren KA, et al. Whiplash injuries in Finland–the possibility of some sociodemographic and psychosocial factors to predict the outcome after one year. Disabil Rehabil 2004;26:1367–72.
Suissa S, Harder S, Veilleux M. The Quebec whiplash- associated disorders cohort study. Spine 1995;20:12S–20S. Gargan MF, Bannister GC. The rate of recovery following whiplash injury. Eur Spine J 1994;3:162–4.
Sterling M, Pedler A. A neuropathic pain component is common in acute whiplash and associated with a more complex clinical presentation. Man Ther 2009; 14(2): 173-9.
Spitzer WO, Skovron ML, Salmi LR, et al. Scientific monograph of the Quebec Task Force on whiplash-associated disorders: redefining “whiplash” and its management. Spine 1995;85(Suppl 20):1-73.
Davis CG. Rear-end impacts: vehicle and occupant response. J Manipulative Physiol Ther 1998;21:629-39.
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