This article by Physical Therapy Web featured writer Barrett Dorko is entitled “Abduction and Courage.” Please leave your comments at the bottom of the page.
You can find an extensive collection of Barrett’s writing at The Clinician’s Manual.
Given what we’ve learned about painful problems and nervous irritation during the past decade or two, I feel it’s necessary to talk about how we may draw conclusions about dysfunction. In my last column I emphasized the significance of interpretation when assessing another. Thinking that what we see or sense is the problem when it’s actually the beginning of the solution has made manual care spin its wheels for as long as I’ve watched it. So, during the past four decades most of the therapists I know haven’t moved. I know that’s not because they haven’t been working hard – they’re just stuck in neutral.
These days I say to my classes, “Your method is your own business, not mine, and I’ve no interest in telling you how to practice. But I have every right to expect you to defend rationally what you do and why.” This is another way of defending your theory, and, to me, it makes perfect sense.
I first came across the idea of neural tension while at dinner with the late David Lamb, one of the original architects of manual therapy education in Canada . He asked me if I’d ever heard of the work of Alf Breig, a Swedish neurosurgeon who had written a book several years earlier about his experience using surgery to resolve pain. Breig proposed that many chronically painful conditions were due to the presence of mechanical tension within the neural structures, not compression. As it turns out, he was right.
How do we know?
Deduction and Induction
Deduction is a form of reasoning that makes specific predictions from general premises while induction goes in what might be called the opposite direction-it moves from particular facts to general statements. Knowing the tolerance of connective tissue to mechanical stress we can say that it will fail in certain ways-this is deduction. Seeing a pattern of callous formation on the hand we can safely assume that repetitive stress is placed upon the limb-this is induction.
Much of is well-known to anyone working toward a conclusion when trying to make a diagnosis. I want to focus on the following.
The following section was inspired by Burton S. Guttman’s essay “The Real Method of Scientific Discovery” (Skeptical Inquirer January/February 2004).
Abductive reasoning follows the following pattern:
Some phenomena P is observed.
P would be explicable if H were true.
Hence there is reason to think that H is true.
In other words, the scientist confronts puzzles that arise naturally during the course of their work, thinking about them in light of their intimate knowledge of the system and then they make a creative leap of the imagination to say, “This would all make sense if H were true.” I find it interesting that this sort of reasoning is both very familiar and entirely absent from the various discussions about evidence based practice.
I evaluate my patient in pain and note that their symptoms are altered with position and/or use. I hear them tell me that they are commonly cool and sense the rigidity in their musculature. These findings constitute P in the equation above. I think, “If neural tension were present it would account for their complaint and the objective findings I can document.” Neural tension is H in the same equation.
This is an act of abduction and requires the investigator to imagine the world in a new way, thus the creative quality of the process. Like any creative act, it also requires some courage. Coincidentally, abduction is defined in the medical dictionary as “a movement away from the median.” Abductive reasoning invariably moves us away from the norm.
So, how did Breig do it? And, how did those of us who have revised our thinking about chronic pain relinquish the memes imbedded in our brains concerning the traditional attitudes about musculoskeletal pain and replace them with the concepts of neurodynamics and the consequences of its abnormality? I’m proposing that we have engaged in abduction. We have listened to countless patients describe sensations that cannot be explained using the paradigm offered us in school and one day said instead, “If abnormal neurodynamics were present that would account for the patient’s complaint-it would explain their story in a way that doesn’t violate what we now know to be true about the nervous system.”
This sort of reasoning is neither common nor easily done. It requires study, creativity and, most of all, courage.
Do it anyway.