>

>





Search SIF


 
|
|
|
|
 

Low Speed Accidents
renfroclic[1].gif (25650 bytes)

One of the more controversial subjects in whiplash research is whether a low speed accident can cause injury.  Since the time of the first car, just hearing the term whiplash has caused some people to roll their eyes.  In addition, there are also several good studies showing that auto insurance fraud is a major American problem.  All of this has caused a boom market for accident reconstruction engineers (AR's)  who try to show that a policyholder couldn't have been injured in an accident. 

 

A year ago, I had a patient who was referred to me a few days after a low speed accident. She couldn't move her neck, had numbness down both arms and both legs, and was extremely tender over the sternum. She related that she had hit the steering wheel with her chest because she wasn't wearing a seatbelt and had been leaning forward. A bone scan revealed a bone bruise of that area. Since she was 3 days before her wedding and I was concerned about instability, she was placed in a collar and walked the isle with it on. A few months later, her insurer hired an accident reconstructionist to prove she couldn't have been injured. When I got the report, much to my surprise, the engineer had somehow concluded that her injuries were a figment of both my and the radiologist's imagination!

This past few years, some engineers have started to claim that it's impossible to be injured in a low speed accident. This assumes that there is some magical injury threshold below which nobody gets injured. What would you need to know in order to accurately predict whether or not someone could or couldn't be injured in a car accident?

  • Velocity and properties of the vehicles (this is usually considered by the accident reconstructionists)
  • Vector or which direction the car was hit (this is never considered by the AR's as part of the injury threshold. This is despite the fact that the medical literature associates greater severity across multiple studies for patients exposed to rear impact vectors. The fact that AR's don't consider this in adjusting injury threshold also contradicts two recent studies that show that the C5-C6 facet joint does get injured in low speed, rear end MVA's.)
  • The position of the head and body at the time of impact (AR's never consider this, despite the fact that multiple studies associate being out of position at the time of impact with a more chronic injury).
  • The type of seat (never considered by the AR's, despite a recent NHTSA study showing that seat type does correlate with injury)
  • The medical condition of the patient at the time of the accident (never considered by the AR's, despite common sense and the medical literature dictating that a 70 year old woman has a much greater risk of a chronic injury than does a 20 year old male)
  • The size of the occupant (never considered by the AR's, despite the fact that multiple medical studies associate lower body mass with a higher risk of chronic injuries)
  • The preparedness of the occupant (never considered by AR's, despite the fact that multiple medical studies associate an unprepared occupant with more severe injuries)
  • The relative degree of tightness of the major prime mover and stabilizer muscle groups of the neck at the time of impact (Never considered by the AR's because it's impossible to determine outside the lab, thus making the calculation of an injury threshold impossible. Why would this be important? Engineering tells us that every time a 150 pound man jumps from a height of 3 feet, his femur (big bone in the thigh) should fracture. However, biomedical engineering tells us that it doesn't fracture because the quadriceps muscle cushions the blow.)
  • The relative position of the joints in question at the time of impact (Never considered, again an impossible calculation, yet important. A football player who gets hit with his knee locked is always more vulnerable to injury than one who has his knee freely mobile.)

As a physician who has treated tens of thousands of patients with whiplash, this engineer stance isn't based in science or common sense. Many of the patients I've treated with herniated discs have had some minor inciting event such as a cough, sneeze, or just looking over their shoulder.

What we can say for sure is that all low speed accidents don't cause injuries, however some low speed accidents can cause significant injuries. Only an experienced physician who has performed a good interview, record review, soft-tissue exam can make this determination.

 

Here are some links to help if you find yourself in this situation: