Friday, February 21, 2020

Nervi nervorum and pain as perception

This post is a wee break from summit postings because as we know, we need to carry on with what's going on right under our noses and not just bathe in nostalgia for recent events. 

Two things came to my attention yesterday that I think perfectly sum up pain.

First, its treatment, at least of pain that stems from a crabby nerve, i.e., neuropathic pain. I won't go into the many kinds of neuropathic pain that exist, because there are several ways nerves can be crabby and reasons for it.
Let's just say that in my line of work, you never know. You can only guess from someone's story, which is why it's important to listen to the story.
Generally, manual therapy followed by some movement instruction is a good go-to for chronic pain that stays in one place and varies with position or rest. That implies that only one nerve or few are involved, and the nervous system has contained the problem, so is therefore healthy. In other words, the pain isn't anything to do with the central nervous system itself, it's doing its job just fine, keeping the problem localized to an area (e.g., low back) or limb (e.g., pain at the knee). This sort of pain has more to do with the behaviour of the person living inside the nervous system, probably. Easy peasy. Well, not at first - there's a learning curve. Or maybe I should say, there's an UN-learning curve. Because all the people who lean toward helping people clinically with their pain problems are first saddled with a TON of biomedicalese and Type 1 diagnostic errors and labels for pain that make it seem like mesodermal derivative causes their pain. But don't even get me started on that, and stop me from complaining about all the treatment models there are out there that focus on irrelevant minutiae like biomechanics and muscle and fascia and discs and whatnot.
Can we at least agree that pain is in the nervous system and stop all the BS about joints etc.?
Usually movement helps, so we should always remember that motion is lotion.

Here is one thing that caught my eye, put in front of me in fact by my facebook friend Alice: a 2016 review paper about nervi nervorum.
Papers like these are as scarce as hen's teeth but essential for manual therapy models in my humble opinion. I first heard about nervi nervorum probably about 40 years ago as I sat in Loren Rex's (Bear's) classes at the Ursa Foundation in Edmunds, Wa.
Since then I've seen perhaps three papers about them, this being one of them.
Why do we need to understand nervi nervorum to be a manual therapist?
Because, if we want to have a conceptually accurate (or at least less-wrong!) model for our work, we need to understand everything we can about nerves. 

Neurons are the most excitable "tissue" in the body, and come from ectoderm. I think ectodermal derivative, which makes up the entire nervous system, is pretty special that way. There are even papers out now about how excitable skin cells are, and, lest we forget, skin cells are also from ectoderm. And we literally (!) can't touch anything but skin. Which is why we should toss all operative illusions that we can have any kind of direct effect on anything lying beneath.
We touch people and that helps change their perception of pain. This is "dermo."
We pull skin sideways, and that tugs a bit on actual nerves, so we can add a layer of neurodynamics onto that. That's "neuro."
Things change for the patient. That's "modulating." 

And we aren't doing that - their brain does that.
And a nerve does not have to be injured for its nervi nervorum to be able to start complaining.
Which takes me to the next thing I saw which fits beautifully: This wonderful video from MindField, on touch. 
The narrator starts out peripherally with thermal grill illusion (illustrated by alternating cold and hot hot dogs!) and ends up showing how easily one can induce nocebo in a person such that they send "pain" out peripherally from their own perception, in a demo of fake laser.

Pain is perception!

Perception is so wily it can predict, then impersonate, "sensation." 



1. Manoel Jacobsen Teixeira, Daniel Benzecry Almeida, Lin Tchia Yeng, 2016, Concept of acute neuropathic pain. The role of nervi nervorum in the distinction between acute nociceptive and neuropathic pain. Rev Dor. São Paulo, 2016;17(Suppl 1):S5-10 (translated from Portuguese)

2. Moehring, F., Cowie, A. M., Menzel, A. D., Weyer, A. D., Grzybowski, M., Arzua, T., . . . Stucky, C. L. (2018). Keratinocytes mediate innocuous and noxious touch via ATP-P2X4 signaling. 2018; 7: e31684

3. Touching: Skin cell to nerve cell communication uncovered. Jan 18, 2018

4. Touch - Mind Field (Ep 6), Feb 15,  2017, YouTube. 

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