A disc bulge

Aug 1, 2010 by

Some readers gave us feedback from last month’s Garagram.   Thank you, for this helps us to know what is effective and what is not.

In particular, for some readers, we missed the mark in explaining what really happened.   Accordingly, I’ll try again, from a different direction.

To start out, let me review the scientific method.  As the judge said to Perry Mason, “Where are you going with this?”   I’m laying a foundation for later discussion.   The scientific method starts with a hypothesis, an unproven theory.   The scientist then proposes an experiment to validate the hypothesis. If the theory is correct, then the experiment will have the predicted outcome.

When the scientist conducts his experiment and the results support the hypothesis, he publishes those results.   Other scientists are invited to repeat the experiment to prove the point.   When a large group of scientists have achieved the same result, they generally accept the hypothesis as fact.  It is no longer just a theory, now you have a consensus.

Now if someone later conducts the same experiment and gets a different result, then that disproves the hypothesis.   Note that this scientific method can never absolutely verify a theory, but it can falsify a theory.   As Albert Einstein said, “No amount of experimentation can ever prove me right; a single experiment can prove me wrong.”

In forensic investigations we deal with historical events that cannot be scientifically repeated in exactly the same way they originally occurred.  Historical events have dozens of known variables  (most non-repeatable) and thousands of unknown variables.   Having said that, we have a problem as the insurance and legal industries require an answer as to the mechanism of causation.   Ascribing causation must therefore be made by individuals with training and experience in that field of the particular loss.   This is why we hire experts.

When an expert expresses an opinion about causation, it is based upon his observations of the particular failure and how the characteristics of this particular failure match those of other failures that he has seen in his professional career.  He does not say “This, with absolute certainty, was the mechanism of the failure”.    He does say, “My expert opinion of the failure was …”   He is correct in his opinion, if he was given all the data and he acted in a diligent, unbiased, and truthful manner.

Now let us return to last month’s case.  In this situation, the insured’s vehicle struck the claimant’s vehicle. The claimant filed for permanent disability due to lower back pain.   GEI was retained to review and comment on the claimant’s MRI, which was submitted in support of the permanent disability claim.

Our PhD biomechanist produced a seven page report to the client, which was heavily edited to become the page and a half of the Garagram.

At no point did we say that the claimant was not in pain.   We did not say that he was not permanently disabled.   We did not, in any way, say that he was faking.

What we did say, was that the injuries that were exhibited were not caused by this single auto accident.   So what was that based upon?

This opinion was based upon the review of the MRI, the training and experience of the expert, and a review of applicable studies done by dozens of researchers on disk bulge causation.

Hundreds of theories have been proposed and scientifically tested to answer the question, “How do discs fail?” The scientific literature is rich with studies on this topic.

The consensus is that when you put enough force on a disc, in a single event, to cause it to rupture, you will also discover that the surrounding bones will break before the disc ruptures.  Several of the studies that support this consensus were referenced in the paper.

So what does cause a disc to rupture?   Many scientific studies demonstrate that repetitive overloading will rupture discs, (hence, the many bad backs of people who spent 20 years carrying heavy loads).   We also know that a large percentage of the population have disc bulges with no clear causation mechanism.  Many of them are asymptomatic, which is to say, that even though they have disc bulges, they are pain free and have a full range of motion.

Returning to the case at hand, the biomechanist opinion was that the observed injuries (the disc bulges shown in the MRI) were not the result of the single auto accident.

Did the accident make him feel worse?   Most likely, but that was not the question we were asked. We were asked, “Did this specific auto accident cause the disc bulges?”

The answer was no.

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