CHAPTER 54 Sociocultural Evidence and Whiplash
INTRODUCTION
Approximately one million diagnoses of whiplash-associated disorders (WAD) are made each year in the United States alone. The health and economic burden to society is substantial and made worse by our inability in most cases to identify a specific structural cause of ongoing complaints of pain and disability. In 1995, the Quebec Task Force (QTF) on Whiplash-Associated Disorders (WAD) did, however, make an important contribution by providing a grade 0 to grade 4 classification protocol based on the available literature.1 This classification system has been widely used both by clinicians and in research studies.2,3 The classification system is convenient because grades are primarily based on physical signs and symptoms. A patient with no symptoms is classified as grade 0. The more severe cases are grade 3, in which patient symptoms associated with neurological signs caused by a specific structural diagnosis, e.g. disc herniation causing nerve root compression, and grade 4, in which patients have symptoms caused by cervical fracture and/or dislocation. Ninety percent of ‘whiplash injury claims’ are, however, classified as grade 1 and grade 2.4 Grade 1 WAD classifies a patient who reports neck pain, stiffness, or tenderness with no other physical signs. Grade 2 WAD defines a patient who reports neck pain, stiffness, or tenderness and signs including reduced range of motion and point tenderness. The QTF classification of WAD is shown in Table 54.1.
Table 54.1 Clinical Interpretation of the Quebec Task Force Whiplash-Associated Disorders (WAD) Classification Scheme
| Grade | Injury (example) and Symptoms | Signs |
|---|---|---|
| 1 | Possible muscle sprain | Normal range of motion |
| Spinal symptoms included neck stiffness, pain, or tenderness only |
Notes:
Although a structural diagnosis is often conjectural or unknown, up to 50% of whiplash victims with WAD 1 or 2 report persistent pain for more than 6 months after their collision.5–7 Despite the availability of modern imaging techniques and despite the increasing use of interventional diagnostic and therapeutic procedures, the incidence of chronic pain following whiplash injuries continues to rise. In this chapter, we de-emphasize the structural approach and instead discuss the cultural disparities of chronic whiplash, and review literature that suggests chronic whiplash pain can be better explained by patients expectations and by symptom amplification. We will argue that research efforts should be focused on reversal or prevention of the psychocultural phenomena that contribute to chronic pain following whiplash injuries. We emphasize diagnosis and treatment based on evidence and not ever-increasing use of unproven invasive interventions.
THE EVIDENCE ON CULTURAL DISPARITIES IN WHIPLASH
Some cultures are Petri dishes for chronic whiplash and some are not. Every study reported from Canada,5,6 Sweden,4,8 the United States,9 England,10,11 Ireland,12 and Norway13 on the outcome of patients classified into WAD grade 1 or 2 indicate a high prevalence of chronic pain. In these studies WAD 3 and 4 are either excluded or represent only a small minority of subjects and the vast majority of chronic whiplash complaints are classified as WAD 1 or 2. Even though patient samples were captured as ‘acute cases’ using different methods, such as insurance claims databases, advertising to primary care clinics, or from emergency departments, the reported prevalence of chronic pain are similar. No matter the source or whether questionnaires were or were not used, all studies from these Western countries confirm the high incidence of chronic pain after acute whiplash. On the other hand, using similar methodologies on the same WAD 1 and 2 classified patients, researchers conducting studies in Lithuania, Germany, and Greece report a very different incidence of chronic pain following whiplash injuries.
Lithuania
Lithuania is a country in which there is no or little awareness or experience among the general population that a whiplash injury is a reason for chronic pain and disability. Collision victims do not often seek extended medical attention, and the possibilities for secondary gains are minimal. In a controlled, historical inception cohort study published in 1996,14 none of the 202 subjects involved in a rear-end car collision 1–3 years earlier had persistent and disabling complaints that could conceivably be linked to the collision. Both collision victims and controls had the same statistical occurrence of symptoms including neck pain, headache, and subjective cognitive dysfunction. In a later prospective, controlled inception cohort study,15 47% of 210 victims of rear-end car collisions consecutively identified from the daily records of the traffic police had initial pain. The symptoms disappeared in most cases after a few days. No subject reported collision-induced pain later than 3 weeks, compared to Canada where a mere 50% were symptom free by 6 months.5 After 1 year, there were no significant differences between the collision victim group and the control group in frequency or intensity of neck pain and headache. In a historical cohort study,14 31 collision victims recalled having had acute or subacute neck pain. In most cases symptoms lasted less than 1 week and only two subjects had neck pain for more than 1 month. Due to recall problems, the true incidence of collision victims with acute symptoms such as neck pain and/or headache was unknown. However, the prospective inception study provides a 95% confidence limit for the true prevalence of acute, post-collision symptoms as 40–54%.15 Because none of the 180 subjects in both Lithuanian studies was reported to have persistent and disabling symptoms due to the collision, the possibility of chronic pain was less than one in 60 (p<0.05). Thus, these studies evaluated either alone or together have sufficient power to reject the approximately 50% estimates5 of the development of the so-called chronic whiplash syndrome in other countries.
Greece
Chronic whiplash syndrome may also be rare in Greece. In 130 consecutive collision victims suffering acute whiplash symptoms, 91% recovered in 4 weeks. The remainder had substantial improvement and recovered within 3 months.16 Extending their series to 180 patients confirmed this results, not only for recovery from neck pain, but from the other symptoms commonly reported as part of the acute injury syndrome.17
Germany
Germany also may have a low incidence of chronic whiplash pain. In a study of physical therapy treatment, by 6 weeks the active treatment group and control (healthy) groups were equal in their symptom reporting. Even the group given only a collar for 3 weeks and no other therapy recovered by 12 weeks. In this study the acute whiplash injury patient had no greater risk of reporting chronic symptoms than found in the general, uninjured population.18 A prospective outcome study by Keidel et al. of 103 subjects in another locale in Germany found the same good prognosis: recovery often within 3 weeks, and virtually all within 6 weeks.19 Similar, rapid recoveries have been found in other parts of Germany.20
Symptom expectation
The differences between outcomes in these three countries cannot be ascribed to methodological issues, since methodological issues do not prevent researchers in countries such as Canada or Sweden from showing the existence of a high frequency of chronic pain. The diagnosis of a WAD case is the same in Sweden, Canada, or Lithuania – those who report symptoms after a collision are labeled as WAD – and the diagnosis of WAD 1 or 2 has no supporting objective manifestations or it would be classified as grade 3 or 4. The vast differences in outcomes cannot be simply ascribed to different medical systems, since Germany, Greece, and Lithuania also have different systems, but show similar outcomes. There is no evidence for the existence of cultural stoicism. Patients with rheumatoid arthritis in Lithuania or Germany report the same symptoms and disabilities as those in North America.21,22 If cultural stoicism caused Lithuanians and Germans to underreport chronic pain, it should do so for chronic pain from rheumatoid arthritis. There must instead be a common factor amongst Lithuanians, Germans, and Greeks that differs from, say, Canadian or those from the United States. One such factor may be symptom expectation. Ferrari et al. have examined levels of expectation for outcomes after acute neck sprain in Canadians, Lithuanians, Greeks, and Germans.23–25 The studies showed that the responses of the Canadian, Lithuanian, German, and Greek subjects in their expectation of chronic disability due to rheumatoid arthritis were remarkably similar. The acute ‘whiplash’ symptoms anticipated by all these groups are also very similar, but there is a markedly different expectation of the duration of these common ‘whiplash’ symptoms. Canadians commonly expect certain symptoms to be chronic, while Lithuanians, Greeks, and Germans do not. This data is consistent with the hypothesis that the chronic whiplash syndrome is in many cases culturally conditioned illness, and that symptom expectation may be an important factor that accounts for some of the variance between the ‘Whiplash Cultures,’ where the chronic whiplash syndrome is epidemic in proportion (e.g. North America, Scandinavia), and ‘non-Whiplash Cultures’ such as Lithuania, Greece, and Germany, where the acute whiplash injury is common, but the outcome benign, recovery being measured in days to weeks.
Thus, we should be focusing on why a particular whiplash patient has brought themselves for treatment and what factors may be making their pain more severe, and their coping less effective, before we immediately assume that the answer lies in biomechanical explanations. Besides symptom expectation, research suggests we need to consider many other factors, including what we as clinicians do or fail to do in the assessment and management of acute whiplash patients.
THE EVIDENCE ON PATIENT ASSESSMENT
The literature on history-taking and physical examination of the whiplash patient usually focuses on the prognostic factors for WAD grades 1 and 2. Because of small patient samples done in a single geographical location, individual studies may not be helpful for identifying reliable prognostic factors and may not apply to other patient populations. In fact, as reviewed by Quebec Task Force1 there are only a few studies focusing on prognosis and outcome in WAD 1 and 2. The largest study with less selection bias, and greater breadth and detail of data concerning collision parameters, demographics, and symptoms as predictors of outcome is the Saskatchewan-based cohort by Cassidy et al.26–28 While the study by Cassidy et al.26 is controversial because the influence of the tort or no-fault system in Saskatchewan, there can be little doubt that the size of the population studied, and the extensive data gathering concerning individual subjects, makes this the most powerful study of whiplash prognosis.
The study by Cassidy and all other pre-2001 outcome studies were analyzed by Cote et al. specifically to identify prognostic factors.28 The analyzed studies consistently showed the following postinjury factors were associated with poor outcome: age greater than 40; female gender; more intense baseline neck or back pain; more intense baseline headache; the presence of baseline radicular signs and symptoms; and the presence of depressive or other significant emotional distress symptoms within the early weeks after injury. These factors were prognostic in both the tort and no-fault system as opposed to the effect the tort system had on prognosis.26 More important were the factors that did not predict outcome. (See Table 54.2 for a summary.) Though pre-1995 studies had suggested that factors such as head position at time of collision, initial X-ray findings, the direction of impact, and amount of vehicle damage were prognostic, subsequent, larger, and better designed studies have not affirmed these findings, and have even contradicted them. Furthermore, in the Saskatchewan study the location of impact, seat belt or head restraint use or position of head restraint, the general health before the collision, previous whiplash injury, or symptoms before collision were of no prognostic value. In fact, the value of various prognostic factors are based on pre-1995 studies that were both small groups of highly selected subjects with inadequate data collection.
| FACTORS REPEATEDLY SHOWN TO BE ASSOCIATED WITH A WORSE OUTCOME |
