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Section 6. Research Priorities for Whiplash-Associated Disorders

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▪ Orientation

Considering the human toll and economic impact of WAD, relatively little is known about this common problem. Studies of neck injury in animal acceleration-deceleration models clearly document one end of a spectrum of tissue damage. Whether lesser trauma in humans can cause enough injury to explain the symptoms seen in WAD cannot be deduced. Although considerable work has been done on WAD, much of it is flawed, uninterpretable, or inadequate to form rational clinical or health care policy. Fundamental questions remain regarding the pathophysiology, diagnosis, treatment, clinical course, and prevention of this disorder. Based on a critical assessment of the published evidence, the Task Force has made a number of recommendations to fill what we perceive as critical gaps in knowledge. Central to these efforts are: 1) a proposed terminology that, coupled with measures of severity, will make future studies comparable and 2) attention to rigorous study design and execution in any new studies.

Future studies would benefit greatly from a standardized description of patients, their sources, physical findings, and symptoms of prognostic significance. Standardizing the assessment would ensure that critical baseline information is collected and that studies done in different locations can be compared with one another. Improved precision and standardization of findings would permit the evaluation of the clinical value of conventional radiography and newer, but considerably more expensive, imaging techniques that display soft tissues in previously unimaginable detail. These latter techniques such as MRI may ultimately provide an understanding of the pathoanatomy. of WAD. In clinical practice, MRI may provide more sensitivity and information than we can interpret, unless studies are done with sufficient numbers of carefully characterized subjects spanning the spectrum of WAD. These tests, as well as electrophysiologic or neuropsychologic studies in WAD, must be evaluated in terms of their clinical value in improving prognostication and outcomes. With better clinical correlation, in this era of increasing technologic capacity, public expectations, and diminishing resources, the cost-effectiveness of these tests must also be evaluated. Paradoxically, new imaging techniques could also restore the history and physical examination to a central role in the initial evaluation of WAD patients and, in the absence of anatomic information, make the history and physical examination the gold standard for the evaluation of other diagnostic technology.

Improved clinical characterization of WAD would also contribute to true population-based studies of the spectrum of disease and its clinical course. This would allow comparisons in different settings, especially different disability claims systems, and help to understand the clinical and social determinants of prolonged symptomatology, disability, and health resource utilization.

The Task Force was disappointed, despite an exhaustive literature search, by the studies evaluating the common therapeutic interventions for WAD. These studies as a genre are flawed; few met even minimum methodologic standards for scientific rigor. Even in the studies that were well done, small sample sizes and the use of multiple therapeutic interventions in the same subjects made it difficult to deduce the benefits of individual treatments. The lack of crisp endpoints using standardized, valid, and reliable measures, particularly patientcentered ones, made it impossible to pool results or to do secondary analyses of effect sizes or of their clinical importance. The imprecise categorization of patients into prognostic strata and the confounding effect of different disability laws made generalizations impossible.

The philosophy of the Task Force in evaluating treatments was one of prudence in the absence of evidence. We required that any therapeutic intervention should do more good than harm and that health care should not medicalize a condition or reinforce disability behavior. Some therapeutic interventions such as analgesics, antiinflammatory agents, and antispasmodics have not been evaluated specifically for WAD; their value for other musculoskeletal injuries might be generalized to WAD. The remaining group included essentially harmless but either ineffective or marginally effective interventions such as soft collars, special pillows, prescribed exercises, postural attention, and traction. Where there was an effect, it was small and of short duration. The other category consisted of interventions that were expensive because they were labor intensive or done by professionals and were either unproven or marginally beneficial. These included manipulation, mobilization, spray and stretch, steroid injections, and a host of physical approaches to administer heat or cold topically or to the deeper soft tissues.

With a planned research agenda, we should have the resources to remedy the shortfalls in our knowledge of WAD.

There are several options for conducting research in this area depending on the research question, context, and feasibility. A variety of alternate designs may be used, for example, historical or prospective cohort studies, case-control studies, and case-cohort studies. The randomized controlled trial is the preferred design for evaluating interventions.

We have divided this agenda into two categories: a) problems of high priority requiring immediate attention and b) problems of importance to be undertaken in the longer term.

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▪ High Priority Questions-Research To Be Initiated in the Near Term

  1. What is the prognostic significance of factors detectable and measurable at the outset of a collision in WAD? Which factors predict good outcomes, notably early return to full function and usual work? Which factors predict poor outcomes?
  2. What is the performance, including validity and cost-effectiveness, of diagnostic approaches for WAD at inception? Approaches needing immediate assessment include:
    • History taking
    • Physical examination
    • Plain radiography and other imaging techniques
  3. What is the efficacy and cost-effectiveness of common therapeutic interventions for WAD? The interventions needing immediate assessment include:
    • Prescribed rest
    • Manipulation
    • Specific physiotherapeutic and physical medicine treatment
      • Mobilization
      • Other exercises
      • Postural advice
      • Traction
      • Passive modalities and electrotherapies
      • Psychotherapeutic interventions
  4. What is the effect in WAD of a clinical strategy encompassing early intervention and emphasizing activation, the promotion of mobility and assertive occupational rehabilitation?
  5. What are the results of implementing the Quebec Patient Care Guidelines for WAD? An evaluative process should be incorporated into their implementation.

The problems deemed to be “urgent and essential” imply studies that can be completed in 5 years. At that time, a new Task Force should be established to monitor new evidence, the resulting changes, and to contemplate new opportunities.

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▪ Investigative Challenges of Importance To Be Undertaken in the Longer Term

In the longer term, research should be focused on the development and evaluation of:

  • Demonstration models with different configurations of health professionals with contrasting arrangement of access, referral, and team function, accompanied by formal evaluation of their impact, particularly among WAD patients in a chronic phase.
  • Demonstration models of alternate methods of reimbursement to health professionals and compensation for patients. The models should enable assessment of formulae linked to results rather than process and should include incentives for good outcomes, without penalizing patients who have intrinsic or unavoidable poor prognosis. All modalities should be eligible for evaluation including capitation and salaried reimbursement arrangements.
  • Demonstration models of new curricular components oriented to WAD and related principles of the management of musculoskeletal conditions.

In the long term, research must evaluate the effectiveness of headrests, seatbelts, and other automotive engineering strategies in preventing WAD. In addition, research must address the pathophysiology of WAD, particularly with the goal of understanding the evolution of WAD.

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▪ Quality of Research

As noted in the “Orientation” section, research already done and published in the literature was found seriously deficient in terms of adherence to conventional standards of research in clinical studies, epidemiologic studies, and projects from other relevant disciplines. The most common deficiencies of published research reports on WAD found by the Task Force were:

  • Lack of clarity in statement of study purpose, research question, or hypothesis.
  • Inappropriate study design to test research questions or form conclusions.
  • Lack of appropriate denominator.
  • Lack of controls or suitable reference group for comparisons.
  • Absent or unclear statement of inclusion-exclusion criteria.
  • Sources of subjects that introduce intrinsic selection biases.
  • Substantial losses to follow-up resulting in potential for biased estimate of outcome frequencies and determinants.
  • Ascertainment of outcomes subject to investigator and patient reporting biases.
  • Measurement methods whose reliability and validity are not established.
  • Absent or unclear statement of interval between collision and study entry, or wide variability of interval.
  • Inappropriate statistical analysis.
  • Inadequate statistical power (small sample sizes).

The Task Force stresses that future research must avoid these and other shortcomings. The scarce resources available should be protected by subjecting research protocols to the highest rigor of peer review, preferably with international panels of scientists.

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▪ Future Research

The tables in Appendix III include a comprehensive statement of specific research recommendations, many of which have not been delineated in the research agenda described in this section. The additional recommendations concern important questions. Their importance is subordinate to that of the unanswered questions that this agenda sets forth. The reader is referred to those tables.

Although all the unanswered questions are important to Quebec, it would be inappropriate that agencies in Quebec should be solely responsible for funding and support of the activities proposed. The same questions are relevant in other provinces of Canada and in other countries. We are encouraged that some research on risk factors, prognosis, and treatment is already underway in a collaborative way between investigators in Saskatchewan and Sweden; principals from both studies are part of this Task Force. This is a model for international and interdisciplinary research, which this Task Force endorses, to enhance the widespread relevance of the findings and the quality of the effort invested. We encourage all interested parties, including government funding agencies, insurance companies, universities, researchers, and health care professionals to share the responsibility of finding the solutions to this important health problem.

© Lippincott-Raven Publishers.