In the past few decades, communities have been repeatedly confronted with health-related dilemmas that are difficult to resolve. Individuals, on the one hand, seek cures or control for fatal and chronic diseases that science cannot provide. Policy makers and those who pay for health services question whether investments should go to aggressive preventive intervention or to high technology for treatment, or to a mix of both. The intensity of these dilemmas has been driven by recent international recession and virtually universal cost containment strategies in developed countries.
Since World War II, there has been pressure to depend more on sophisticated technology. Such technology often goes through a trendy “fad phase” and is not always subjected to rigorous scientific evaluation before its use becomes widespread. The price paid by society for such shortcomings is aggravated by procedureoriented fee-for-service reimbursement schemes that reward “doing” much more than “thinking.” Once such procedures become part of the mainstream of clinical practice, it becomes very difficult to evaluate them because of legitimate ethical concerns about withholding accepted interventions from patients whom might need them.
The Department of Epidemiology and Biostatistics at McGill University and its hospital-based Divisions of Clinical Epidemiology have been addressing controversial social and medical issues for governments and public agencies since 1976. Task forces have been formed to address such problems as the value of the periodic medical examination, the disproportionate disability and associated expense of occupational back injury, the congestion in Montreal-area emergency rooms, and possible causal associations between exposure to pesticides and Reye's Syndrome in children and exposure to sour gas emissions and respiratory disease and cancer.
This Task Force addresses the problem of whiplash and its associated disorders. Neck pain is to the automobile what low back pain is to the workplace. Whiplash-Associated Disorders (WAD) are becoming increasingly worrisome in the Western world. In Quebec alone, approximately 5000 whiplash cases annually account for 20% of all traffic injury insurance claims, and the average period for compensation has increased from 72 days in 1987 to 108 days in 1989.34,35 In British Columbia and Saskatchewan, two other Canadian Provinces with single-payer motor vehicle insurance programs, claims for whiplash injury represent 68% and 85% of the automobile injury claims, respectively.35,98 In addition, whiplash injury presents a substantial financial burden to society.
▪ Mandate of the Task Force
During 1989-1990, the Quebec Automobile Insurance Society (Société d'assurance automobile du Québec [SAAQ]) approached Dr. W. O. Spitzer, of the Department of Epidemiology and Biostatistics, McGill University, about the possibility of an in-depth analysis of clinical, public health, social, and financial determinants of “the whiplash problem.” The frequency of the clinical entity labeled as whiplash is high; the residual disability of victims appears significant in magnitude, and the costs of care and indemnity are high and rising. There is considerable inconsistency about diagnostic criteria, indications for therapeutic intervention, rehabilitation, and the appropriate role of clinicians at all phases of the syndrome. Little is known about primary prevention of the condition, and virtually nothing is known about tertiary prevention of serious disability.
The leaders of the SAAQ appreciated the need to understand the epidemiology; mechanisms of injury; clinical definitions and syndromes; natural history; evidence of effectiveness of prevention, treatment, and rehabilitation; the role of psychosocial factors; and the impact of the health services system in general to formulate a rational approach to the problem. The Task Force was charged to make specific recommendations to deal with these issues. The SAAQ was committed to a system that would provide fairness and compassion to persons with neck injury following motor vehicle collision, medical care of the highest scientific standards, realistic strategies of primary prevention, and judicious management of society's resources. Most importantly, the SAAQ acknowledged the preeminence of scientific evidence.
▪ Basic Approach
Despite the expertise of the Task Force and our scientific advisors, opinion had to take a backseat to evidence. Thus, all conclusions and recommendations were based on scientifically admissible studies, when available. The general rules of evaluation of evidence were adopted in advance and fine-tuned to adapt them to the body of evidence as the work of the Task Force progressed. Experience in science, clinical judgment, and wellreasoned opinion were not totally disregarded, but they were always subordinate when admissible scientific evidence was available.
When confronting controversies of clinical diagnosis and management, a special challenge is to enable a process whereby methodologists are educated about the clinical issues, and clinicians are trained in the design and analysis of experimental and nonexperimental studies. Understanding the important issues is crucial when decisions about public health policy are under consideration. The strategy used by this Task Force to assemble valid data from the many published original studies evolved over two decades. First, it required adoption of criteria of eligibility for the type of publication to be considered. In this effort, we eschewed review articles and reports of secondary analyses, except as background reading or as sources of references to primary reports. Only original research was considered as scientific evidence.
As described in detail in later sections, we standardized the process of evaluating original articles screened as eligible. This standardization ensured that all important features were weighed carefully each time by reviewers. The various types of experimental and non-experimental studies required specific variants of the abstraction forms. The specific tactics and procedures were developed initially during the Canadian Task Force on the Periodic Health Examination,26,101 and the methods of selecting, weighing, and synthesizing original data from multiple sources were refined during successive Task Forces (e.g., the New Brunswick Task Force on Reye's Syndrome and Environmental Risk Factors,102 the Inter-University Task Force on Passive Smoking,103 the Working Group on Low Osmolality/High Osmolality Contrast Media,55 and the Quebec Task Force on Vertebral Column Disorders in the Workplace104). In the current effort, we refined our methods, including extensive modifications of the forms for critical appraisal of articles.
In the educational field, Slavin coined the descriptive phrase "best evidence synthesis" and argued that a method of aggregating data is needed that avoids the constraints and pitfalls of meta-analysis and the haphaz-ardness of unstructured literature review.97 The key features of best evidence synthesis are predetermined explicit criteria of quality for articles, type of data used in the aggregating process, a diligent search for relevant unpublished material, and presentation of the results as ranges of estimates of effect with probability statements linked to the boundaries of the ranges, if necessary. Meta-analysis, in contrast, seeks a single estimate of effect. Because meta-analysis and best evidence synthesis are vulnerable to publication bias,100 the search for unpublished material mentioned above is important in both types of undertakings.
After 3 years of deliberations by the Task Force, the evidence was found to be sparse and generally of unacceptable quality. The original research articles in the literature strained our capacity to adhere strictly to best evidence synthesis methodology. The following important elements of the method were retained: guidelines on the type of research papers that could be considered, a diligent search for relevant unpublished articles, a structured critical appraisal with predetermined checklists and rating scales, and an unwillingness to overinterpret the synthesized evidence with single estimates of effect. Applying a priori operational criteria of quality when accepting or rejecting studies could have resulted in rejection of virtually all articles considered. We used judgment to identify valid and useful components of published reports, which taken as a whole would not have met conventional standards. Therefore, this scientific monograph presents qualitative descriptions of the aggregate data, rather than ranges of estimates of effect.
▪ Scope of the Report
The mandate of the Task Force included a broad variety of questions to be addressed. It was not feasible to have, in a single Task Force, sufficient representation of all areas of expertise needed to carry out a best evidence synthesis on all clinical questions and on all questions concerning prevention. Consequently, it was decided to focus the full Task Force on clinical issues, specifically risk, diagnosis, treatment, and prognosis of whiplash. Issues regarding mechanism of injury and prevention of whiplash were addressed by consensus in a subgroup that included an injury epidemiologist, orthopaedist, and engineer with outside consultants. This group conducted a review of the literature on road safety, biomechanics, and injury control with respect to the mechanism of whiplash injury, prevention of collisions, and the environment of moving automobiles.
Parallel to the Task Force review of the scientific evidence, a subgroup of clinicians was formed, with experts from the various specialties involved in diagnosis, treatment, and rehabilitation of WAD. They reviewed the basic anatomy, physiology, and semiology underlying clinical interventions for WAD. This permitted a better elaboration of the treatment algorithm and recommendations for professional education.
Because of the above consensus process, the entire Task Force was better prepared to describe, define, and classify the problem of whiplash, a process essential to the evaluation of the literature and to any subsequent recommendations. These results appear in Section 3 under the heading of "Consensus Findings." One of the most important contributions of the Task Force is the Quebec Classification of Whiplash-Associated Disorders. We hope our classification will allow more meaningful discussion of clinical issues and allow comparisons of future research studies through the adoption of standardized diagnostic criteria for WAD.
Surprisingly little evidence relevant to epidemiology, clinical decisions, preventive interventions, and rehabilitation was found. Accordingly, for many aspects covered by its mandate from the SAAQ, the Task Force was forced to invoke expert opinion to make recommendations in areas where the literature was weak. To supplement this process and to gain a better understanding of the epidemiology of WAD in Quebec, we identified a cohort of whiplash subjects from the injury claim files of the SAAQ and examined prognostic factors in the recovery process. These findings appear in Section 2 under the heading of "The Quebec Whiplash-Associated Disorders Cohort Study."
This Scientific Monograph presents the essential scientific background from relevant clinical, epidemiologic, basic science and engineering disciplines, the methods employed, conclusions and recommendations. Given the dearth of valid information in the international literature, it emphasizes research priorities in the near term and the longer term. These can be found in Section 6: Research Priorities for Whiplash-Associated Disorders.