Beyond Neural Tension: Exploring Neurodynamics with Michael Shacklock

[00:01:34] Mark Kargela: I remember learning about neural tension in physical therapy school and thinking it was all about stretching nerves. As my career has progressed, I've seen how it is much more than that. My early understandings of neurodynamics had me doing a lot of stretching that sometimes really helped some people, but also sometimes really flared a lot of patients up.

This week's guest, Michael Shacklock, is a leader in helping us better understand and apply neurodynamics. He teaches worldwide and has written a great textbook called Clinical Neurodynamics. We sat down and I asked Michael about the issues when we use the term neural tension versus a more comprehensive term such as neurodynamics.

[00:02:05] Michael Shacklock: I'm glad you asked the question and it's a very insightful question on your part because that is truly a, I think it's a problem in what we do. Um, and it still has not gone away.

[00:02:18] Mark Kargela: Michael discussed how pain science has influenced his practice and some of the concerns he has had over bias that is created in some clinical practice.

[00:02:25] Michael Shacklock: Well, one of the things that that I fell in love with, with pain sciences was everything's connected and there's no such thing as a discrete lesion [00:02:34] in the nervous system and everything can affect everything else. So it then gave us license to choose what we want, which I think is dangerous.

[00:02:44] Mark Kargela: We discussed our use of prevalence research in lumbar imaging findings and how it is often portrayed inaccurately to patients, which can risk clinicians not thoroughly examining a patient to determine if their imaging finding is accurate. is clinically relevant to them.

[00:02:57] Michael Shacklock: So then, if we're going to use it, we should say to the patient, actually, the conclusion with meta analyses, systematic reviews, supports the statement, some disc hernias hurt. We need to know in you, if yours does.

[00:03:13] Mark Kargela: It was great sitting down with Michael, and he's been someone I've really looked up to in my development.

This episode is packed with a lot of practical information that you can take immediately to your practice to better help your patients. If you'd like to go deeper on discussions on neurodynamics and all things pain, then make sure you check out our community at modernpaincare. com forward slash community.

Now, on to the episode.

[00:03:33] Announcer: [00:03:34] This is the Modern Pain Podcast with Mark Kargela.

[00:03:38] Mark Kargela: Welcome to the podcast. Michael,

[00:03:40] Michael Shacklock: thank you for the opportunity. This is going to be great.

[00:03:43] Mark Kargela: Absolutely. This has been something I've been looking forward to. I was speaking to you before we hit recording. I've been reading your work for gosh, a while now.

It was a big part of our fellowship training as we were going to learn neurodynamics and how to kind of really Applied treatments, it may be aimed at the nervous system. So I'm looking forward to picking your brain on that. And maybe as we start today, I'd love to hear kind of your journey, uh, of who's been your big influencers and how did you get to where your focus is on this area?

[00:04:10] Michael Shacklock: Well, it's a, it's a good question. I must say I, I don't find that easy to answer 'cause, because I, I, I've sort of, I try, I look for a lot of things. You know, you, there's a ton of information out there. But for me, um, I was a young, young fellow, young kid. Graduated when I was 20 years old, um, from high school and then into PT school at 20.

Finished there at 20 and then traveled around New Zealand and did private practice [00:04:34] work and worked in hospitals where pediatric burns right through to respiratory and general medical surgery. There's a whole lot of stuff there in our rosters in the public hospital system, you know. Uh, but as an undergrad, I got really interested in manual therapy.

And when you're training, you can't focus too much. You have to pass your exams. So I pushed a lot of that interest aside and then finally I read a paper, um, by Robert Elvey, Bob Elvey, who's a West Australian physical therapist. He did some anatomy stuff on a movement of nerves in the cervical spine, nerve roots.

And it's sort of, oh gosh, gosh, you know, and then I went to Australia, um, and, uh, did postgraduate study there, did master's degree, in which we had to do a research thesis, and because I was interested in nursing, mine was on neurodynamic sequencing, which is where we could maybe change the sequence of movements of a neurodynamic test, uh, to figure out if we could make treatment, uh, techniques or physical forces a bit more [00:05:34] specific, because neurodynamic tests are a big, big, long, Aren't they?

Uh, and so to me, specificity, uh, was still, I was important to me then just, just for, to see if it would work. Um, he's either in a mechanism basis or clinically, we haven't got a clinical now, but the research supporting, the, starting to support the, the specifics in mechanics. Then I met David Butler and many of you will be familiar with him for good reason.

Um, and he. He and I ended up having, uh, I joined his clinic with Helen Slater, and we were really interested in pain science then. We had this, this international pain, uh, science, uh, conference, bunch of PTs came over from the Northern Hemisphere and so forth. Patrick Wall of Melzack and Wolfram was there, and a bunch of, you know, psychiatrists right through, Bob Alvey, David, myself, Helen, Mark Jones, there's a bunch of people speaking at that conference.

So David, for me, was a huge, uh, Huge influence because at that time he was writing his first book, Mobilization of the Nervous System. And to me, that was a huge jump forward because it was a whole [00:06:34] new organ that we could treat annually. There'd been a lot of discussion in early history and so forth about certain things in nerves, but Dave put it together into an organ.

So to me, that was that was gold. Um, and, uh, at that point, I started to feel, uh, soon after the, we were all teaching and stuff with my group, and, um, I started to feel a bit frustrated, not with any malice or anything. It was more that I felt that we'd gone from, uh, we're doing mechanical treatments, and then we hadn't really done much with physiology.

And that's critical. But we know blood flow has to continue in nerves, otherwise they fail. We know that changing your blood flow produces inflammatory changes, sensitivity issues, and so forth. So I was really interested in physiology. My most hated subject at PT school finally ended up being interesting.

And, um, I did a lot of reading in that area and felt that they should be integrated with mechanics. It should [00:07:34] be integrated with mechanics. And so that was when I wrote this. Uh, critical neurodynamics where I proposed the idea that we should be calling this a neurodynamics approach rather than a specific neural mobilization approach or a mechanical approach, because it's both.

And so I wrote this part of neurodynamics where the proposal, luckily, was accepted in some areas anyway, and it grew from there to clinical neurodynamics because for me, neurodynamics is a, is a con, it's an intellectual construct, but the clinical neurodynamics is how you apply it. And that, that's, that's where the battlefront is and where clinicians need resources, uh, and, uh, skills.

And so I was interested in, in concluding the two and then taking a step further into the musculoskeletal system. And now I'm sort of settling on movement related nerve pain. Integrated with musculoskeletal function. So that's a little bit of my journey. In the interim I've done research and I'm doing a PhD in lumbar radiography and so forth.

And so that's kind of my, a short [00:08:34] story of my journey.

Yeah. No, that's, that's, that's a journey. Bob Alvey's name seems to come up a lot, especially when it comes to neurodynamics and some of the things around that. Definitely one of the pioneers who was really writing about it and studying it early on and had some great influence on some people.

I'm wondering, one of the things I do remember in some of your papers was this discussion of kind of transitioning from this kind of traditional view of like neural tension testing to neurodynamics. You kind of talked about it a little bit with your answer there, but I'm wondering if you could kind of unpack that a little bit of, of why that terminology neural tension is kind of limited.

Cause I still see it all the time. I think you still see physio still. That's the maybe biased and maybe it's just something that time and things needs to go away.

I'm glad you asked the question and it's a very insightful question on your part because that is truly a, I think it's a problem in what we do.

Um, and it still has not gone away. Now, if you go, if you go to the history of Bluey Gifford, And David Butler wrote the, the, the [00:09:34] concept, exactly the title, the concept of adverse mechanical tension in the nervous system in the general physiotherapy. Great. And then before that, Alf Breig, who many chiropractors, um, know about, was looking, he turned at adverse mechanical tension in the central nervous system.

And so Brieg was at that time looking at a general theory. Now, I don't think people, all of you realize this. I believe he was creating a general theory of symptom production with the mechanical function of the nervous system. And at a fine level, ultrastructural cellular level, axonal level, et cetera. I think you got it right, because if you imagine a little plaque or an inflamed area or nerve, the axons have to pass a greater distance along that course.

So they're tighter, and it is tension. And tension is a trigger at a microscopic level for axonal changes. So actually, at a fine level, I think you got it right, but it went into clinical practice where I think we did it wrong. And the reason [00:10:34] is there are layers. For instance, a classic one is a Friday afternoon surprise.

People hate this. I just, I would get confused by it. You're doing a slump test on a patient that had low back pain sciatica. You bend their head down. Ah, that reproduces my leg pain. You straighten the knee and the pain improves. You're doing this to the nervous system, but the pain's better. It does not make sense in neural tension terms.

At microscopic level, If I'm thinking about Stephen McGill talks about, and I agree, it might be an underhook where, where, sorry, an overhook where the neck, we know that it moves the nerve roots upwards. Um, and it could, uh, uh, uh, touch an interfacing structure such as a disc hernia, overhook or excess, uh, supra ex, um, shoulder, uh, hernia.

Um, but when you move it down, it relieves the pain, so the tension is gone locally. But in our level of analysis, it's a movement [00:11:34] dysfunction with altered force. And so, I felt that, We need to make, understand more mechanisms. So this is where I feel that neural tension, I, I, I wouldn't say it's a failure, I, I would say it's a step in our knowledge, um, and we should go beyond neural tension.

We should stop calling these things neural tension tests, and we should stop calling neural tension, and actually even then flossing in neural mobilization, I'm not very enthusiastic about, because it's much more complex, and if we emphasize the right mechanisms, um, then we're in a good place. And so movement to me is the next step.

[00:12:12] Mark Kargela: Yeah, it sounds like your, your application is kind of evolving as it should, as science has kind of moved forward and things. Um, I'm, I'm wondering with, you know, pain science has been the big, you know, explosive topic, or maybe over the last 30 years, probably even longer for folks that realize it's probably been talked about longer than that.

But I'm wondering if you can kind of talk, discuss how that's influenced maybe your, [00:12:34] Your application, your approach as we've kind of seen maybe a little bit more of the complexity of pain pay up, play out. I know you've talked about movement related nerve pain now and in different things, but I wonder if you could, you could discuss that.

That's an excellent question. You're asking all the key ones that I find difficult to answer, which is good, which is really good. Um, now if we go to the pain sciences, well one of the things that I fell in love with, with pain sciences, was everything's connected and there's no such thing as a discrete lesion in the nervous system.

Um, and everything can affect everything else. So it then gave us license to choose what we want, which I think is dangerous because we have fads, we have factions, we have, we have a fragmented set of professions now and unfortunately what I'm seeing is bias having huge influence. On, on, on our clinical practice and, and for me, um, the big bias or emphasis or [00:13:34] opinion is the body's not important because the brain is.

It's all sensitivity. It's all how you think and feel. Um, the biopsychosocial, unfortunately, bio only has three letters. And so the emphasis has gone from bio to psychosocial and physiology, if you will, or chemistry. And, um, the idea that everything's connected justifies, helps support the idea that we don't have to focus on anything except what we like.

And, and again, I think that's dangerous intellectually. And finally, it will produce Clinic Fail 101 because it is actually Science Fail 101. And so, I'm a bit critical these days, but I'm trying to keep quiet, not quiet about it, but polite about it. Um, a really good example is, um, you know, Carpal Tunnel Syndrome, cervical radiculopathy, lumbar radiculopathy.

You can find changes along the whole system, absolutely, in the brain, everywhere, but it's triggered. By something, and there [00:14:34] happens to be pressure on the nerve root from a pathology. If it's bad enough, these people get paralysis. And a large, about 20 percent of people after a year are still not normal.

And so the idea is that we don't need to worry about pathology anymore. So let's forget about the body and let's do, don't worry, be happy, keep moving. Now, that is absolutely right for a lot of problems, but it's not right for everyone. And that's my opinion, and um, there are some people out there who I feel, feel unfortunate, I feel sorry for them, and there's a lot of people out there who are getting told this symptomatic discommunity is not hurting.

Uh, you know, um, for instance, we now know one of the cornerstones of why a disc hernia becomes symptomatic is instability. If you get, um, a disc hernia, it doesn't always hurt, that's true. But if it, if it coexists with lumbar instability, it's much more likely to be painful. And that, that's been pretty much validated now.

And so if we take a [00:15:34] microcosm of our knowledge in the pain sciences and generalize it, we can get it wrong. Okay. Through the brain changes, the person changes, you get depression, but it doesn't cause discommunions. You know, where you're upset and you write L5. And, and so whilst I'm a huge fan of pain sciences, I think the difficulty is, is getting them, getting the emphasis right.

And I think it's, I personally cannot justify a lot of, a lot of patients leaving the body. No problem about doing pain sciences, but leaving the body is often a problem. And it's based on ideology in some people, in some situations.

No, I think, uh, you, you bring up some great points. It's, it's, it's difficult sometimes you see even on social media, just where, where people are defaulting to the psychosocial and in some cases, maybe that is driving a lot of But I think we still as physios need to be Do our due diligence and have a good, solid biological [00:16:34] examination to make sure we're doing our thorough peak that yes, sometimes lumbar radiculopathies, lumbar disc herniations need specific movements, specific treatments aimed at the tissue.

I just think there's such a taboo now for whatever reason to like, I think that the bio for some folks doesn't matter, but

absolutely. And if we think of the brain, brain science, pain science, there are, there are, there are now discussions about what areas of brain become active with pain and therefore brain activity and pain relate closely.

Um, but that's physical. That's physiology. So we can't, I feel like there are contradictions. And, um, There's a bike, the continuum everywhere, everything's connected. But don't worry about that stuff. It doesn't, to me, it doesn't, it's, it's, Yeah, I'm not keen on it. I don't think, I don't think it's intellectually correct in a lot of cases, [00:17:34] and I think it's really important that the clinician entertains a broad range of possibilities.

And a beautiful one is disc hernia. I mean, we know that if you, early biases were someone has back pain, let's do radiology, oh my goodness, there's a dyskernia, let's take it out. Yeah, that's a bias. The, the opposite bias is actually looking at people without pain and still finding disc hernias. It's still biased because you're not differentiating between symptomatic and asymptomatic in relation to that variable.

And what is now shown, two systematic reviews and a meta analysis now show that people with back pain have more disc hernias than those with pain. without back pain. Now if we're going to use, if we're going to use prevalence to tell our patients that their pain, their back pain, their dyskonia is not hurting, then we have to do it accurately, do it properly.

The prevalence in people with back pain with dyskonia, of dyskonia is higher. So then if we're going to use it, we should say to the patient, actually, the conclusion with meta analyses, systematic [00:18:34] reviews, supports the statement, some dyskonia is hurt. We need to know in you, if yours does.

And have a clinical process to kind of hash that out with a person and not just jump to conclusions without that due diligence and thorough, uh, examination skills.

Yeah, I, I agree. I I remember that systematic review that kind of talked about, you know, the prevalence of imaging findings, and I can't even remember the name of the author. I've tried to pronounce it. It's a really complex one side. You bring, bring

[00:19:04] Michael Shacklock: tea. Bring tea. Is that right? Bring, yeah. That, that's, there you go.

Sees.

[00:19:08] Mark Kargela: That's the first time I've heard it pronounced, so I'm going to go with it. Uh, but yeah, no, it's my practice. Nice, nice. I, I saw that study come out and that one was just like plastered all over social media, like, look at this. And like, and I've, I've made a PowerPoint slide one that, you know, I think there's maybe some helpfulness with it when patients have these, you know, findings, especially when they're clinical exam, they don't have radiculopathy, they don't have any, you [00:19:34] know, neurologic signs.

They don't have any signs where. You know, it's the back of the back exam looks pretty clean range of motion is good and there's, but it's more maybe so you can kind of de threaten the situation showing them that, hey, a lot of this stuff can happen. We see a lot of people who don't have symptoms can have some of this stuff, but then for the patient that I'll be where it is validated that yes, this is, in fact, a symptomatic disc herniation.

And then, like you said, the study that he followed up with, I think it was afterwards. Uh that talked about yes Well, the prevalence of these findings tends to be more prevalent in people that do have pain So we need to be but that one didn't get as much press I think there were some people that said hey We got to pump the brakes and not realize and realize like yourself that that there are some of these things we need to be mindful of that can be painful that we can't just Jump to the conclusion that all these things could be asymptomatic for everybody again having that clinical processes Is huge.

I'm wondering if you'd speak a little bit to your PhD focus as far as I know, it's kind of a lot around lumbar radiculopathy. We're speaking around the lumbar spine. So I'd love to hear what you're up to with that and what you're [00:20:34] what you're studying and maybe what you're Uh, finishing papers looking like, or I don't know where you are in the dissertation phase, but

[00:20:41] Michael Shacklock: yeah, I mean, I'm running the dissertation now and I published the done the research that's published and I'm just writing that and I'll have to do, you know, things like defense and study course, study points and things, but the basis for my PhD is the idea that, um, we know that, The cause of radiculopathy in the presence of discing is pressure.

It, it, it's, it's pretty bli and simple. It's pressure. If you don't have that, if you don't have a discing and you don't have other pressure problems like stenosis, osteopaths, and so forth, um, it's less likely that you can need the radiculopathy. Ha you get an arachnoid or, or some problems or it's, you can have other biological aspects to it.

But the biggest cause, the most common cause is dyspenia pressing on move root. Let's just say we'll focus on that group. Um, what I've been interested in doing is it's kind of two layers. One [00:21:34] is challenging the idea that we should be mobilizing nerves that are already forced on, because when we think of neural mobilization, the logic is, Oh, this is the nerve root is forced on.

That's what is causing the problem. So let's treat the disc. Okay. That doesn't work within mobilize the nerve, which also applies force. But it's already forced on. So, uh, my feeling is that a lot of neuromobilization, uh, actually if it does produce a benefit, and sometimes it does, is actually producing adaptation.

It's not actually treating the immediacy in the, in the current mechanisms. And so, Um, what I wanted to do is find new mechanisms for unloading the nerve root for pain relief. Because people who limp in with severe sciatica want pain relief. If they can't sleep, their whole life's affected. Family life, work life, [00:22:34] trans, you know, picking up the dog, whatever it might be, it's all affected.

And, uh, you know, significant. group of people after a year still not okay. And so this idea of just keep moving and do exercises, whatever you need to do non specifically. Yes, it does help people, but I'm more interested at when my PhD, you've got to focus when you do a PhD. I focused on what are some stuff, what are some things we're not doing that could give people pain relief, but it's in the body.

It's in the physical behavior of the nerve root and disc. So we were able to, um, I must yeah. Credit Marine Cole at RADA, he's a really good, he's a whiz kid, he's um, he and I worked together and he created this, uh, way of measuring spinal cord movement non invasively with the straight leg raise. So you can actually do the straight leg raise and see the cord move and measure it.

So, we were able to, through his, his techniques, um, digital, it's digital now, so it's with [00:23:34] MRI, you don't have to do anything except, well, sorry, you do it a lot, but you don't have to cut it, it's, it, you can do it in a healthy subject, people with dyspnea, all sorts. So, we're able to show that, uh, or measure the chord movement with the straight leg raise as a looking glass, into lumbar nerve root movement.

Because we know from the, the intraoperative studies that measure nerve root movement with the straight leg rays show significant, huge reductions in nerve root excursion. But you can't measure that non invasively. It's technically not available. So he was able to mark the conus medullaris at the base, which is the base of the cord and measure its movement with the straight, its displacement with the straight leg rays.

And it's about 3. 5 milliliters for 60. degree straight leg raise, and it's about seven, just over seven nanometers for the same thing in bilateral straight leg raise. So the idea is that we were trying to figure out the mechanisms related to how we might unload a nerve root mechanically with a neuroendocrine test, [00:24:34] which seems strange, but what we figured out was it's contralateral.

So if you do a contralateral straightening raise, you lower the cord and you unload the contra, the other nerve root by unloading its tension from above down. So the core, the nerve root now is hypothetically able to displace away from the disc hernia and ease the pressure, therefore ease the pain. So That, that was a first, that was a really step.

[00:25:05] Mark Kargela: Interestingly, so like, clinically, I'm just trying to, to bring that to, to how I might work with my next lumbar hernia or disc herniation with some ridiculous symptoms. Um, so in that case, are you, you're saying that, hey, we would do like cross straight leg raising, maybe mobilizing the contralateral. Side and then clinically is that something we would then hope to see some symptom relief in that that affected leg?

[00:25:29] Michael Shacklock: Yes Now for me if it's movement related pain it responds quickly to movement like I [00:25:34] stand Too much and it hits my leg or I sit too much Then you expect a quick quick change because it's it's provoking quickly such as these quickly Um, and so the, my favorite patient for this is the one who's got continuous leg pain, some, maybe some pins and needles.

They don't have too severe a neurological deficit. Um, and you say, it's a lying down, how's your leg? And they say, well, it's really hurting. I've got it. And they move, don't they? They sort Flex it and they wiggle to try and ease their pain. And I say, okay, just, just stay there. Let's just make your hip, shoulder, leg comfortable, external rotation, put on a pillow as best you can.

And tell me what happens when you do 90 degrees hip flexion and just straighten the knee to the end of the hamstring range or a bit of dorsiflexion and so forth, just hold it there comfortable into position. with a bit of stretch maybe in the hamstrings a slight and ask the patient how's it feeling now.

Now for me there's a, there's an algorithm and that is if the ipsilateral limb pain is provoked with the contralateral test [00:26:34] that approach is ruled out. We don't use the contralateral to ease their pain because it provokes and we've shown that people who have this have reduced movement. And so that's kind of good physical, um, analysis, Subject of response for physical movement to rule in or rule out, rule out a technique.

But some people get pain relief from it. And that's probably the bulk of, of, of, in the mechanical function and people that we've looked at with Dyspenia, um, that's kind of the bulk of what people show. Most people don't have a cross str gray sign. They can, but it's not, it's not the biggest percentage.

It's not over 50% people. And, and so, um, that cross reg race sign that rules it out, but sometimes they get relief when you do it. So that rules it. Super easy to do at home. Super cheap. Here's, here's how you can produce your own pain relief. Yeah, uh,

[00:27:28] Mark Kargela: having had some pretty rotten sciatica in my day, uh, I can imagine if I found something [00:27:34] that produced even an ounce of relief, I would be jumping all over it.

So definitely something to try in the clinic for sure. Um, and you, you've mentioned some of the responses around the slump that, and some of the things that don't fit the textbook definitions of what we expect. I think the cross straight leg raise being one of those like, you know, We often look at it to see if it, if it like recreates that, you know, opposite side, you know, with some of the statistics around being diagnostic around lumbar herniation, but now using it as a, as a treatment, I think obviously could be something very helpful for somebody.

I know you have on your website too, with your article on acute lumbar radiculopathy, is it possible to reduce force on the nerve root? I think this is kind of where you're speaking to that a bit and you guys. Yeah, you got some nice references there too. So I'll put that in the show notes for folks to to check out to kind of read that because that's some some great stuff.

Um, I am wondering with you. We've talked about more of the mechanical pressure components. So I'm wondering if when you see physiologically where it's more maybe the inflammatory because there are [00:28:34] probably a subset from my understanding where there might not be physical contact where the disk is actively pressing and producing that force and pressure on the, Okay.

Uh, when it's more of an inflammatory component, is that something that we would see different clinical signs or things that you would maybe approach differently with those type of patients?

[00:28:52] Michael Shacklock: Uh, certainly, dare I say, if you really want to know why someone has a radiculopathy, do radiology. Oops. You're not allowed to do that, are you?

Because you might scare the patient. Uh, so unfortunately, we're in that difficult situation of Following, you know, evidence, which is, if, if you do too much radiology, it's not, it doesn't put the patient in a very healthy, um, function, um, situation. So you might, I, I realize that there are difficulties with that, but, um, I, I personally don't think we, we can be definitive about why someone has pathy without medical investigation.

And so, uh, you know, [00:29:34] some people would say, well, you know, it's, it's 80% of 'em get right in a year. Don't worry. Moving. If you're at the end of the year with a, still with a foot drop in sciatica, that has not solved your problem, and in my opinion that's a failure, because, um, I personally am not so averse to radiology, because I don't think it's those magnetic waves.

I don't think they cause a problem in their spine, and I don't think they cause pain. I think it's education about why you're doing it, um, whether the clinician puts a positive spin on it and a factual spin on it. You say, look, some dyspneas don't actually press on the nerve root. So if we, if we do radiology, let's do a deal.

Will you agree that, We are gonna find out if it is or is not relevant because real, you've gotta realize it might not be. And if that's the case, it actually helps us sort out what's safe for you to go into rehab with and if, if you, [00:30:34] uh, if you, uh, have a safe spine, if you will put it that way, uh, then how about we do a deal on your exercises and so forth, and, and you'll, let's, let's agree that if we can eliminate a specific cause, that will will give you a better opportunity to do rehab.

So, my opinion about radiology is I'm not averse to it like I used to be. Um, it's, and there's even a recent study, um, by some English physios that, that just ask people, tell us about your chronic back pain, tell us about your frustrations. And some of them said, I'm not doing rehab. And I said, why? Because I haven't been investigated and no one knows what's wrong.

And so that's a golden opportunity to, to say, okay, if we get it investigated and there's not really a major problem, will you do rehab? And a lot of them said, well, yeah, I would. But I'm, I'm scared because I haven't, but we don't know what's wrong. So for me, radiology, and I'm diverging a bit, can be used positively or negatively.

It's a tool. It's, it doesn't give you a direct outcome. And so for me, [00:31:34] I like radiology if I'm not, if I'm not sure about why someone has back pain, sciatica or whatever, but it's used judiciously and carefully and not excessively. So. If someone doesn't have dyskonia, if they have dyskonia not pressing on the nerve root, they could have a fissure in the annulus, of, um, um, glucose, amine, all sorts of things into the epidural space there, and that can produce radiculitis, and given severity and prominency that can produce radiculopathy.

And what we also know is that people can actually have pressure on the nerve root initially, but watch it over three months, and the relationship between the pressure, the ischemia, and the radiculopathy actually starts to deteriorate. So, you could get an improvement in pressure, still have a radiclopathy, you could also have an improvement in radiclopathy with stool pressure, so there's some sort of adaptation going on.

So, for me, um, to find out the cause, I think you've got to do investigations. We do, I'm a physio, so I can't do medical investigations in [00:32:34] Australia, except occasional x rays and so forth. That's not adequate. So, um, for my physical examination, you cluster them, of course, you can get a likelihood, I think, an impression about whether it's a dyskonia.

But, um, and so I would say, look patient, he's dyskonia. Good news is you don't have a neurological deficit. So I don't think you need radiology right now. Um, or you've got movement related nerve pain. We've shown you how to unload the nerve root. If we can improve you over the next two weeks, then the importance of radiology diminishes, but if it stays bad, your foot drop remains, blah, blah, blah, blah, blah, then I, I, I would, if I were me, if I were my mother or my kids, or my wife, I would want to know what's there.

So for me, what's clinical features, how they respond to certain things, and then you hit them off, and you funnel them into the right pathway. I'm not sure if that answers your question, but, um, if someone doesn't have a dyskinemia, I'm not going to be doing anything other than, you know, I'm not going to be [00:33:34] doing anything.

Into more, more and more radiology, that's for sure.

[00:33:38] Mark Kargela: It seems like a reasonable approach as far as radiology. I do, I do think there's probably that tendency as we, you know, we see maybe the worst of what MRI studies can do with some patients where it, you know, scares the hell out of 'em and gets them completely, you know, devoid of any valued activities or movements, but with good explanation and education around that.

And we've even seen that with studies where when we really give good education around the normalcy of some of these findings, or, I agree. There are some patients where I've definitively. That lack of an image has been a massive barrier to them engaging. So if that's what they need to start moving forward.

And, you know, there's definitely the clinical science to do so, then, you know, let's do it. Um, but yeah, I think there is definitely a tendency as of late to be very adverse to radiologic investigation. We had Ian Harris on and he mentioned some of the, Challenges with radiology reports, right? Because radiologists love to, to like, you know, their job is to not miss any blemish [00:34:34] that is in the spine.

If they're doing their job correctly, they're identifying everything, which in their world, great, but in the patient's world, man, that scares, that's some scary terminology from time to time. So more importance for us as physios and hopefully as physicians who may be. Interpreting these and reporting these to patients that we maybe de threaten some things and then, you know, validate some things too when it's appropriate, um, as well if they're experiencing radiologically confirmed, you know, that this clinical symptom is very, you know, radiologically confirmed that we need to kind of be able to do that.

And then also paint the picture of, you know, what we know about natural history

[00:35:11] Michael Shacklock: One of the reasons radiologists got a bad rap for diagnosis part is, you know, reliability, sensitivity, all that stuff. But also it's often done in a clinical way. And then context, which is role modeling in a medical context.

And you go to your doctor, they do medical things because they're doctors. Well, when they, um, they come to us and we're functionists. So we teach function. Um, and so part of it is not just [00:35:34] the thing, it's the context that, you know, as you say, it's a medical context and the doctors and experts. pathology and disease.

We're experts at function, so you know, hopefully we can work together well.

[00:35:47] Mark Kargela: Ideally those two mesh together and there's definitely settings where it works well and we have a lot of great physicians who kind of recognize that strength and great physios who recognize the opposite strengths then if we can kind of combine efforts it can really make for the best of both worlds.

I'm wondering if we could speak a bit to, and you've talked about about this already, but I'm wondering where you think some of the challenges as far as application, maybe where physios are missing the mark as far as their understanding and application of like neurodynamic treatments in the clinic.

[00:36:17] Michael Shacklock: Good question. Really good question.

I think neurodynamic tests are still a little misunderstood. Um, I would like to see them, um, called either neurodynamic tests or nerve movement tests, um, and put into a, a, a context. Now we can [00:36:34] also, we can go into bio psychos, you know, the psychosocial context.

Okay, that's fine, but I'm not, that's not what I'm focusing on. What I'm focusing on. If we just think of a clinical algorithm, we're stepping through, we're on the diagnostic pathway, we're walking along on this pathway and we've got to do certain things at different points. And at one point we do a neurodynamic test and that's, that's why we do it, figure out if it's normal or not.

Um, if it's perfectly normal, uh, normal range of motion, Complete an appropriate test for that patient. That means it can tolerate certain tension. It's probably viscoelastic function is pretty okay. Its sensitivity certainly will be okay. So that is really good. We would say that is a normal test.

Therefore they do not go to the neurodynamics hospital. They would likely go to the musculoskeletal hospital because it's normal. So it's like a negative test, if you will. Trouble is, There's confusion. The first main point of confusion is that people seem to think [00:37:34] that when you do the differentiating maneuver, for instance, wrist extension for the upper limb one or dorsiflexion for the straight leg raise, that if it changes the person's response, It's positive, but that's not true.

It is a normal response to that combination of movements. And so, the interpretation is often positive in asymptomatic subjects, so they're false positives. So we can't make a diagnosis with them in so many people, because about 95%, so it can be above 95 percent in some, in some groups. Healthy subjects, it differentiates and it produces a response.

So people would say, well 95%, that, that's rubbish. We can't use that diagnostically. Yeah, that's a fair comment, but only if it's interpreted incorrectly. It's not a positive test. It's just a normal response to that combination of movements. It's the pull your finger back test for the nerve. Pull hard enough, of course it will [00:38:34] hurt.

But the question is whether it reproduces the patient's pain or part thereof, and whether it's with a movement that emphasizes nerve but does not kind of around the area. So if I'm thinking of a shoulder problem, uh, here, and we do a neurodynamic arm, we reproduce shoulder and neck pain, and then we use the wrist to move the nerves in the shoulder and the neck, but we don't move MSK.

So we're not, we're not provoking anything with MSK at that point. If the wrist movement does not change the patient's neck and shoulder pain, good. It's not a neurodynamic problem if that's the right test. But if it does change the person's clinical pain from a different area, we certainly cannot eliminate nerves as a problem.

Because that, when we move the nerve, which is known to happen, then the pain changes, so at minimum you can't eliminate it, at maximum it might implicate nerve. Um, that does, but again at that point it doesn't tell us a [00:39:34] diagnosis. It's just an abnormal neurodynamic response. The next question is why is it abnormal?

Just to say it's some thoracic outlet thing or something. The next step is to figure out why. So we would say that's an abnormal response. Um, what are the, what, what could be causing this and you're going to look at kinesiological function, palpation signs and neurological. You might even get radiology, you know, whatever it might be.

And then the rest of it is to figure out why. So it's really, for me, a neurodynamic test is really only detection device to figure out if the nerve's movement is abnormal or its response to movement is abnormal. Next step, cluster it with other things, figure out why neurological testing and so forth. So it's a physical test.

It's not a diagnostic test.

[00:40:19] Mark Kargela: That's a good point. I think it just gives us, you know, the, the response that you said that we need to have a little bit more investigative work to be done to, to kind of see what, what might be driving that. So, as I have you here, somebody I've read a lot of and, and selfishly, I'm [00:40:34] going to ask him my own clinical questions that hopefully the audience, I'm assuming, might have some of the same questions as well.

Uh, when we have like acute, ridiculous, like really sensitive, you know, nerve roots, is there a time where you might focus more on the. The, you know, local spine versus work in the neurodynamics, or are you even in those acute? I just, I think we've all probably everybody here who's listening has probably flared up a few patients, maybe getting after neurodynamic techniques, maybe too vigorously, not, you know, at a pro because obviously we can do sliders and, and different things.

And we can do other things to kind of decompress nerve roots and, and maybe treat it from a decompression standpoint versus a, you know, tensioning, uh, force standpoint. I'm wondering what your thoughts are.

[00:41:17] Michael Shacklock: Perfect question. Before, let's talk about the PHC, which is unloading nerve roots along, along their course from the top down in the spinal cord, but we can also open the foramen transiently with spinal position.

Now, now let's get to the next step, which is if someone has [00:41:34] severe radicular pain, and it is a compressive problem, if we position them in the open foramen position and they get pain relief, that's a home activity. Really easy. So that, but, and another, the other, the flip side is that physical testing might reveal that if they look up or extend or do each lateral level flexion, it provokes their distal pain.

Now, um, that's got a lot of names in terms of different approaches, but I call that a closing dysfunction. So if someone's got a nerve root problem and you look up and up across to that side and it provokes and it's restricted. I'm just calling it a movement dysfunction in relation to MSK system, but it's, it's neuro, uh, neurodynamic, it's sort of a neurodynamic centric, if you will, where we're categorizing it according to how it responds to the musculoskeletal system.

So for me, a key aspect of neurodynamics is integrating with MSK, how you move, what you do around that system is [00:42:34] critical because this is neuro problems in the context of MSK. That's mostly where they come from. I don't think many MSK problems come from the nerve. It's the other way around mostly. And so what I try and do is figure out if they need pain relief, because the main, three main progressions are pain relief, bit of rehab, high performance.

And so if you load an acute severe nerve root problem at a high performance person, you could really hurt them. As you say, we've all, we've probably, you know, done that. So what this person might need is pain relief. So we do the opposite movement to the dysfunction. Which is open. It's a closing problem.

And then as I improve, we slowly migrate it to improving tolerance to the closing, which I would relate to McKenzie approach, um, and all sorts of other types of movement patterns. So for me, there's a spectrum, and we decide what part of the spectrum we direct the mechanisms at. Unload to start with, a little bit of rehab, high performance.

[00:43:31] Mark Kargela: You bring up some good points because I've had this internal struggle [00:43:34] with like shift correcting for like a McKenzie patient. We know the lateral trunkless is pretty, pretty sensitive to identifying likely a herniated disc. And I've, having had a pretty significant shift with an acute S1 where, you know, reflex and sensory changes and all of the above.

There was no way in hell I was, I tried a little bit of shift correcting, but that was quickly, my body said, absolutely not. I do tend to think more along the lines of that we're starting to adapt tolerance to closing on the side of the affected area. It's not some sort of, you know, migratory of the disc type thing.

[00:44:11] Michael Shacklock: I mean, we're letting natural history of a disc hernia ideally do what it does, but then, Ideally desensitizing that area to where maybe I'm wondering if you could speak to that a little bit. You already touched upon it a little bit, but is that, is that your kind of thought with, with some of those movement approaches?

If we take the contralateral shift, my feeling is it's got two components. There's the local, which is contralateral level flexion, but [00:44:34] you can't continue your normal joint positions from there because you're actually, you're actually not, you're listing, it's a list, but then you correct above it. Okay. So you end up with a shift rather than a, it's a, it's a list and a correction, such a shift.

Um, we now know, because there's some amazing studies out there, that put pressure transducers in the foramen of people with a contralateral shift and people who have sciatica, dyskonia, and don't have a shift. And the pressure in the foramen in the contralateral shift group is about double. That of the ones who don't have a shift for the same general clinical problem and diagnosis and so pressure is a key, as you say, and for some people, it's so high so that they can't tolerate closing or pressure.

So, to tell you the truth, I do what a lot of people wouldn't do, which is open the pain and more put them in a more shifted position. for about a minute because the brain is trying to get them to do that anyway. Brain is saying, I can't tolerate the pressure, move away. [00:45:34] So I'll position them in the open position.

That's the list or shift direction for about a minute and then see if they can return better when they get up. That's it. There's a process to get to and through that. But that's, I see no harm in doing contralateral positioning for contralateral shift. And what we now know also is that even in cadavers, asymptomatic subjects, dyspnea, degenerate spines, osteo, the whole lot, the range of models opening the frame and still occurs with all those models when you do contralateral deflection.

So if you're thinking neurodynamically, That's my problem. A lot of people would worry about the nucleus going to the wrong place afterwards and stretching stuff But so far no so far so good. Um, and it's not weight bearing anyway, so i've found it to be quite safe

[00:46:22] Mark Kargela: That's great Pointer sir, I really appreciate it Definitely as you were speaking to it and kind of what what with the pressure and then definitely having my own Inability to tolerate that pressure it sure makes sense with what we see [00:46:34] Michael, I want to respect your time today.

I really appreciate you spending some time with us, but I wonder if you could share a little bit about some of the courses that you're, you're up to. And I know you're doing some more hybrid formats, but I'm wondering if you could speak to that a little bit.

[00:46:45] Michael Shacklock: Well, Neurodynamic Solutions is teaching all around the world.

We've taught more than 10, 000 people around the world over the years, and we're moving to a hybrid system where we're condensing the upper and lower cost. Quarter courses into one. So the time commitment for attending the in person parts on two days, where it used to be four and the theory then is spread out three months, a month before and two months after.

So, um, and particularly in the US and Canada, it's really flying. I really like those formats. You guys are. Uh, very efficient in your business models. Um, and so, uh, we, we came to the U S I, I come there regularly. We've got two instructors, um, Joseph Ravino in Buffalo, New York, and Michael Maxwell up in, up, up in Vancouver.

Well, in Victoria, actually near Vancouver, he's teaching stuff as well. So, I'm the online instructor always. And at the end of the course, I appear online in front of everyone, do a quick summary on a live online [00:47:34] and Michael and Joan teach the courses as well. So I'm, so I'm teaching as well, the whole thing.

So that's where we're at at the moment.

[00:47:40] Mark Kargela: We'll definitely link the website on the show notes. So folks can check it out. Highly recommend. Uh, the courses, uh, cause great stuff as you can hear with today's podcast, Mike, Michael, I wanted to thank you for all the work you've done and you've really been a big influence on my practice.

And I know a lot of physios out there with, with your work in neurodynamics. So thank you so much for your time and thank you for your work.

[00:47:59] Michael Shacklock: Thank you very much. My pleasure.

[00:48:01] Mark Kargela: Absolute

[00:48:01] Michael Shacklock: pleasure.

[00:48:02] Mark Kargela: All right. For those of you listening, we'd love if you could subscribe to the podcast on wherever you're listening to the podcast, if you're watching on YouTube, if you could subscribe there, we'd love that and share the episode with somebody who's struggling to figure out where neurodynamics may fit in their practice, but we'll leave it there this week.

You guys, you guys all have a great week. We'll talk to you next [00:48:34] week.