Several recent studies have failed to find a correlation between crash velocity and risk of sustaining a whiplash injury. Let us explore both vehicular and human factors that govern the risk of sustaining a whiplash injury.

Vehicular factors in whiplash injury

Impact Velocity and delta V

Delta V or change in the velocity is a relatively easy parameter to estimate and hence it is more popular for injury probability assessment. Delta V is only part of the equation & acceleration is more important parameter. Both acceleration and speed change affect occupant kinematics.

It is also important to understand that the delta V of the vehicle and delta V of the occupant are not always the same.If the occupants vehicle is struck on the drivers side door – a relatively soft part of the car – the driver may be subjected to a delta V much larger than that of his car.

Further it is important to ascertain the occupants seated position at the time of the crash because if the occupant is leaning forward with partially unsupported back then this can lead to injuries.

Vehicle Damage

A large proportion of injuries occur at the speeds below those needed to cause permanent damage to vehicles. There is a paradoxic relationship between the vehicle damage and the risk of the injury. Outcome studies have shown that greater the vehicular damage , the less the biomechanical loading ( and the inverse).

In a LOSRIC study ( Low Speed Rear Impact Crash ), the largest category of injury crashes were graded as having no damage . In these 38% females and 19% males had symptoms. When damage was rated as minor, these percentages were 54% and 34%.

However , there may be subtle signs of damage in the form of damaged or sprung seat backs, witness marks ( stretch marks) on restraint webbing, scrap marks on bumper isolators , and damage to frame and bumper systems that is not visible from the exterior of the vehicle.( Just checking the photographs of the damage not helpful)

Many vehicles will be undamaged at crash severities that are above the range where human volunteers have reported neck and back symptoms.

Vehicle size and stiffness

Severity of injury from a rear impact collision is likely to be proportional to the mass of striking vehicle and inversely proportional to the mass of struck vehicle.

A larger car has more room to crush than smaller car. If both large and small cars crash into a fixed barrier at the same speed, the duration will be much shorter for a smaller, stiffer vehicle’s occupant. This results in much higher acceleration to the head, neck, torso and other body parts, and can make a difference between the injury pattern.

Other Vehicle Factors to consider:

  • Head restraints
  • Seat Belts and shoulder harness
  • Seat Backs
  • Bumper systems
  • Brakes
  • Airbags
  • Collision Vectors – Rear Impacts vs Frontal vs Side

Human factors in whiplash injury

The researchers have looked at engineering and biomedical literature and from this meta-analysis the final answer was that there have not been any studies published in the peer reviewed , scientific literature that have demonstrated a significant relationship between crash severity and (a) acute injury risk (b) injury severity (C) probability of chronic symptoms.

Human factors should be given more important consideration when looking at the probability of the injury risk:

  • Awareness of impending impact
  • Bracing for impact
  • Sex – Females more than males
  • Age
  • Position in the vehicle
  • Stature
  • Ramping – upward motion of the occupant of a struck vehicle which occurs just after the impact. When this happens the head-neck complex may no longer be protected by the head restraint and restraint may act as a fulcrum

Acknowledgment – I would like to thank Arthur C Croft PHD. DC, MSc, MPH of Spine Research Institute of San Diego for providing the coursework that enabled me to put out together this article. Visit Please email me if you need any references.

With the Medco now monitoring the medical reporting industry it has become ever so important to understand the science of prognosis, the ‘holy grail’ of Whiplash!

Whilst it is true that prognosis is not an exact science, the medical expert is expected to give a Magic Number for recovery period.

The industry’s obsession with the magic number of 12 to 13 month prognosis is ill-founded. It is easy to succumb to the temptation of giving a ball park figure of 12 months.

Published evidence on the long-term prognosis of whiplash injury

Over the last 46 years there have been over 53 papers published on the long-term prognosis of Whiplash Injury. In the studies that followed up patients for at least 6 months post accident, the average of the proportions of the patient who are still symptomatic was between 35% – 55%. The patients that remained symptomatic at follow-up were in some cases totally disabled with pain, where as others complained of only occasional bothersome pain.

Whilst 45% of cases may recover in 12 weeks, nearly 55% continue to suffer beyond three months and some beyond two years post-accident. More than 50% will have certain level of symptoms beyond the first year and 10% never recover and can be classed as disabled.

What this means in practical terms for the medical expert writing the initial / first report?

Consider the range of opinion giving regard to the fact that recovery can occur at various stages.

Undertake risk factor analysis through careful assessment & recommend re-examination for high risk cases if they fail to recover in the initial six months.

Recognise that a majority of the straightforward low-risk cases would recover in the first three to six months.

Not get dictated by the industry or the constraints of report writing softwares if these do no allow free text to give a detailed opinion.

Remember, the Medco is only interested in the job well done – opinion and prognosis based on evidence, not whether you get paid £30 or £180!

MedCo will be a new system for sourcing medical reports in soft tissue injury claims brought under the Pre-Action Protocol for Low Value Personal Injury Claims in Road Traffic Accidents. Any Claim Notification Form sent on or after the 6th April 2015 involving a soft tissue injury claim, must have a fixed cost Medical Report commissioned from a medical expert or MRO sourced via MedCo.

With effect from 1st January 2016 medical experts must be accredited by Medco Registration Solutions in order to provide the initial fixed cost Medical Report in a soft tissue injury claims.

There is clearly a certain level of anxiety and uncertainty in the minds of all the stakeholders as to how effective and efficient the system might be. The claimant solicitors are unsure with the prospect of having to use the medical reports written by “random experts.” Some even fear that these reports may well not serve their purpose and not help them to achieve the best possible outcome for their clients.

The medical experts would be under the spotlight. Annual accreditation and Auditing of the medical reports should ensure quality improvement. The medical experts would be expected to give evidence based opinion and prognosis. They would need to invest time and money in keeping abreast with the training required for this particular task. The financial renumeration for the medical reports is clearly a much debated topic.

The MOJ has introduced these reforms as a part their long running goal & ambition to stamp out fraud from the personal injury claims. That is certainly a worthy cause! However , somewhere along the line , the actual medical issue of whiplash injury itself has been rather trivialised and the genuine sufferers may well be swept under the carpet !

The facts about Whiplash Injury

The Myth of Total Recovery

“The soft tissue injuries will heal in 12 weeks.” This perpetual myth is a party line of insurers based on no scientific evidence. There are currently 89 published outcome studies and the common theme that comes out is that whilst 45% of cases may recover in 12 weeks, nearly 55% continue to suffer beyond 3months and some beyond 2 years post accident. More than 50% will have certain level of symptoms beyond the first year and 10% never recover and can be classed as disabled.

This particular scientific fact has significant implications for the claimants solicitors and medical experts alike. If the medical experts fail to carry out the Risk Factor Analysis in their initial reports then they would not be able to point out those cases that would develop chronic symptoms. The cases may well get under-settled on inadequate and incomplete medical information. The medical experts could then be potentially failing in their duty and exposing themselves to the law suits by their own instructing solicitors.

It is important that the claimants solicitors become more probing and inquisitive about the potential long term risks for their clients. Instead of looking for a ball park figure of few months prognosis they should be asking more questions off the medical experts about the “Risk Factor Analysis”.

The MedCo has an opportunity to ensure that the auditing process could in some way address this issue and protect the medical experts from potential law suits.

Low Velocity Impact ( LVI) Whiplash

It has become almost fashionable for the insurers these days to ask the medical experts to look at the photographs of the involved vehicles with no visible damage. Low Velocity Impact whiplash is not a myth and injuries do occur at low speed with no visible damage to the vehicle. There is a whole lot of scientific crash testing data in the published literature to support this . It is an incredibly complex issue and medical exports would need to familiarise themselves with the Biomechanics of Whiplash injury and related scientific studies. The insurers would need to do more than just sending repair estimates and photographs if they are serious about the LVI issue. The claimants solicitors would need to learn to ask questions off the insures and rebut the engineering evidence instead of just folding over and forwarding the photos to the medical experts.

Whilst the financials may not always permit detailed investigations in these cases it is important to ensure that the genuine claimants get all the treatments and the compensation that they deserve. The science is out there to support the cause but both the medical exports and the solicitors need to work together and ensure that the scientific information is well applied in each and every case of Whiplash Injury!

(Source – Training Seminars by Arthur Croft PhD DCMsCMPH, Director , Spine Research Institute of San Diego, California, USA)