Doctors use many words and phrases that non-physicians have a difficult time understanding. A "minimal" problem to a radiologist reading an x-ray of a patient's lumbar spine might be a moderate to severe problem to an orthopedist who is reading the lumbar MRI of the same patient on the same day.
Chiropractors use the same diagnostic tools as the orthopedist. What I think you're confusing, Rusty is the orthopedist who maybe works as a career IME doctor doing 10-15 minute exams who isn't looking for much in such a brief time. Believe me, there are orthopedists who are very interested in "subluxations" (a.k.a. partial dislocations), whether they are found on motion study x-ray, real-time MRI or videofluoroscopic examinations (don't you remember the Kaneoka and Ono study using videofluoroscopy, a.k.a. cineradiography? I know you do. Any chiropractors authoring that one? I don't think so.) In any case, your interpretation of differences between chiros and orthos is not true, at least where I live.
I can't address everything you wrote in this one letter, because the Patriots are about to kick a field goal to win, and I'm getting tired, but you said:
"To apply epidemiology to the study of 'low speed crash injury' one must necessarily rely on the false application of science".
Interesting point. Of course, to apply crash testing to determine injury is also relying on the false application of science. You know, maybe we should scrap the CDC while we're at it. C'mon, Rusty! Even if what you said were true (which it isn't) regarding "intellectual dishonesty", I would say that little or no damage to cars certainly does qualify as a low speed collision (even taking the Kornhauser paper into account). And deductive reasoning, probability and statistical analysis is not "intellectual dishonesty". If Chuck Farmer thinks it's reasonable, so do I. If MacInnes Engineering has found injury at 2.5 mph delta V in healthy subjects, then there's a whole world of bad stuff that will happen in the real world. Maybe you should spend a few hours reading the journal INJURY to see what bad stuff can happen with low force. And no one ever used the word "routinely".
By the way, epidemiology is used for injury as well as illness. You're quite wrong about that. And pain is a very good first indicator that an insult to tissue has occurred. Now, if the fraud rate was, let's say, up around 40% regarding these crashes, that still leaves 60% of persons with real injuries. I'm in a car. I get hit from behind. I have no idea what the speeds involved are. My car was next to that familiar landmark. Now it's 15 feet past it. There's no damage to my car. I'm a little dazed. My neck starts to hurt like hell the next day, and it hurts for several weeks. You're saying that I can't tell the difference between that and a kink in my neck from sleeping wrong that lasts a few hours (or even two days)? Please give that a rest, Ferrari does it better.
And I never said that IIHS data was related to injury potential. You say I "suggested that". No, Rusty, I mentioned the IIHS data because you said that "injuries just don't happen" given a proper head restraint [whatever that is] and some other factors. My point, which appears to be missed (again) is that no one has defined what a proper head restraint is, but that the IIHS doesn't seem to think they are very good on the cars driving our roads today in any case. So your hypothetical good head restraint isn't part of real world driving to any great extent (yet).
Besides, facet injury appears to occur in the cervical spine before the head hits the head restraint.
And no, I'm not saying anything about all defense AR's, just the ones who might purposefully misuse the power they have. I have no idea what percentage of the total AR population they represent. I'm sure it's pretty small. But I've seen enough of the bad reports to worry (just as you [and I] do about my profession).
Your point about vehicle damage and delta V is correct. I am in agreement. There is also no connection between delta V and occupant injury. I believe I saw you in a car crashing head-on into the rear of another once, and I believe your vehicle's delta V was close to 20 mph. Your head snapped forward into an airbag and you were braced. Your head acceleration was lower than many of the other subjects who were rear-ended at much lower delta V's. Other subjects in other tests in Canada and in other places experienced lower delta V's than you and sustained injury. So, no connection between delta V and injury, as I know you agree.
Okay, you had to get pretty specific about the relationship between acceleration "on the appropriate relative axis" and injury potential. You just made my point better than I did earlier. Getting to those specific accelerations from a police report and damage analysis just isn't possible in real world crashes, where so many other factors play a role in injury potential than what's happening to vehicles (i.e., human factors). Nothing disingenuous there.
By the way, those subjects in their sixties with "objective, diagnosed and quantifiable bone disease", what are you trying to say? That you had a few healthy subjects with osteoarthritis you found on an x-ray? Whoa, it was objective, diagnosed and quantifiable bone disease. Please be more specific. The osteoarthritis in most healthy 40-60 year-olds without pain is technically an "objective, diagnosed and quantifiable bone disease". So what? I'm afraid it's a bit more complicated than that. What you're saying is very misleading. If you thought there was any chance of hurting those subjects, you wouldn't have let them volunteer. Guess that "bone disease" wasn't too important, eh?
Gotta go, we won!
Greg Wright
drwright@capecod.net
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