Whiplash-associated disorder (WAD) is a major concern worldwide, with neck pain being the most common complaint following a motor vehicle crash. For years, injury claims associated with minor damage rear impact motor vehicle crashes have been predominantly defended using a biomechanical approach.

This method involves a “crash reconstruction” engineer calculating a crash “delta V” (change in vehicle speed) and often compares the estimated forces experienced by the vehicle occupant with the forces involved in everyday activities, such as sitting heavily into a chair.

Though much of the scientific literature relied upon in this approach was conducted around 25 years ago, it suffered methodological flaws, such as small sample sizes and the use of young, healthy participants only. It has since been proven that experimental crash tests, as well as the volunteers who consented to participate in them, are sufficiently different to the conditions and occupants of real-world crashes, such that the injury risk of the latter cannot be inferred from the former.

To do so would, in fact, assert that injury risk and, therefore, physical outcome is solely and linearly related to occupant acceleration and vehicle damage. This underestimates the potential risks of such crashes across the range of individuals in the driving population.

The traditional approach to WAD is now being challenged by a more holistic assessment. This will, in turn, progressively impact how claims are pursued, how personal injury matters are assessed, and, importantly, how the long-term implications of the injury are managed based on variables previously not acknowledged.

Vehicle occupants vary in age, sex, body mass index and health or illness conditions. Even older people with osteoarthritic disease or existing neuromuscular conditions can obtain unrestricted driving licenses. Contrary to popular belief, even a crash of low impact velocity can cause serious injury in a person with such debility. Research evidence suggests that up to 50 per cent of people who experience WAD after a motor vehicle crash will, in fact, fail to recover fully, regardless of crash severity.

Around half of these people will suffer longer-term complexities that stem from the acute injury. Symptoms that are seen within this group include interference with activities of daily living, ongoing pain (which becomes chronic), muscle weakness and various changes in muscle composition due to maladaptation, sensory and motor disturbances including dizziness, despair over time due to recovery propositions and higher anxiety and depression as these symptoms persist.

The determination of injury causation and outcome in low-velocity motor vehicles using a biomechanical approach is now only “one part of the puzzle”. This historical metric asserts that injury risk and, therefore, the physical outcome is solely and linearly related to occupant acceleration and vehicle damage.

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Careful consideration of the literature will demonstrate that a solely biomechanical injury causation approach is scientifically invalid. The “one-size-fits-all” approach of crash velocity being the only predictor of injury outcome is morphing into a holistic assessment where it is accepted that all vehicle occupants do not have the same injury risk, and as such, the extent and duration of the injury, as well as the associated care required will vary on a case-by-case basis. This includes assessing the vehicle occupant’s age, sex, body mass index, health and potential illness, or other conditions.

Accordingly, the profession is urged to be aware of and counter a “blinkered” approach when assessing WAD-related matters.

Claimants in injury litigation following motor vehicle crashes usually rely on the opinion of a treating clinician to verify the crash as the cause of any persisting injury. Conversely, insurer defendants often rely on the engineering or biomechanical approach as the grounds for denying any causal relationship between the crash and the injuries claimed.

By design, the biomechanical causation method will consistently conclude that a minimal-damage crash is no more likely to cause a medically documented injury than the forces experienced during everyday activities such as walking, running, sitting down, nodding, or sneezing. Conversely, it’s prudent to incorporate, far more broadly and inclusively, the body of evidence available to consider the injury and outcome risk of crash-exposed individuals, including the aforementioned variables.

In addition, the complexity of recovery for patients with WAD is seen to be exacerbated by the low levels of adherence to existing best practice guidelines. This is demonstrated by the common and cyclic scenario to different clinicians (general practitioner, allied health, etc.), repeat visits, imaging referrals, additional clinicians, surgical referrals, blood tests, and specialist appointments, to name a few.

While this is occurring, the patient is less able to work or exercise, is financially impacted, frustrated, and stressed, and is often no longer able to lead the life they lived prior to what may have been a low-velocity crash.

Therefore, the duration of personal injury claims is likely to start to become more complex and longer, with the expectation of higher settlement figures. The advice to the profession is as follows:

• View WAD-related claims holistically: Regardless of whether your client is the plaintiff or defendant, legal professionals are encouraged to seek a holistic appraisal in the resolution of the matter. Importantly, legal professionals are discouraged from approaching a WAD-related motor vehicle crash injury litigation matter from a solely biomechanical approach (as historically relied upon by insurance defendants). In addition, consider the immediate and potential long-term effects of the incident and its related impact on the individual.
• Understand the scientific validity of counterfactual evidence: Specialists are increasingly being engaged to assess counterfactual expert evidence and provide an expert opinion on whether the case is scientifically and validly founded. This includes considering the plaintiff-related factors that increase their injury risk, even in the event of a minimal damage rear-impact motor vehicle crash.