Ep 362 - The Mechanisms of Back Pain with Dr. Stuart McGill

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0:00:50.5 Darren Buford: I'm Darren Buford. 

 

0:00:51.4 Kristin Coverly: And I'm Kristin Coverly. 

 

0:00:52.6 DB: And welcome to the ABMP Podcast, a podcast where we speak with the massage and body work profession. Our guest today is Dr. Stuart McGill. Dr. McGill is a distinguished professor emeritus, University of Waterloo, where he was a professor for 30 years. His laboratory and experimental research clinic investigated issues related to the causal mechanisms of back pain, how to rehabilitate back-pained people, and enhance both injury, resilience, and performance. His advice is often sought by governments, corporations, legal experts, medical groups, and elite athletes and teams from around the world. His work produced over 245 peer reviewed scientific journal papers, several textbooks, and many international awards. He has taught thousands of clinicians and practitioners in professional development and continuing education courses. 

 

0:01:41.1 DB: He continues as the chief scientific officer for BackFitPro Incorporated. Difficult back cases and elite performers are regularly referred to him for consultation. Dr. McGill's books and continuing education courses for practitioners and education for back pain individuals are available online at backfitpro.com. Hello, Dr. McGill and hello, Kristin. 

 

0:02:02.2 Dr. Stuart McGill: Good morning, Darren and Kristin. 

 

0:02:04.6 KC: Good morning, and thank you so much for joining us on the ABMP Podcast. We are thrilled to have you with us and to talk to you today. And because this is your first time on the podcast, we're gonna start with what we call your origin story. So, Dr. McGill, tell us, how did you become interested in working in the field of back rehabilitation and how'd you make that switch from being a lab scientist to a clinician?  

 

0:02:25.3 DM: It's probably less of an interesting story than you're thinking. It's very large in part happenstance. First of all, it's my nature. My brain naturally analyzes how things work. As I progressed through my education and degrees, I ended up completing a PhD in spine biomechanics and then very early on became a professor, and never imagining in a million years that I would become one. But nonetheless, when I started our scientific investigations, we only had one question, and it was, "How does the spine work?" And starting from there, different clinical groups, orthopods, neurologists, the manual therapy professions and clinicians like yourselves would invite me to come and give a talk on what we've discovered, very specifically on how the spine worked and functions and pathways to pain and that kind of thing. And then they would say to me, "Would you come and see a patient with us? What you just described sounds like the missing piece with regards a difficult patient that we're dealing with." 

 

0:03:44.3 DM: I said, "Well, no, I'm not a clinician." And this was about 20... Well, it was about 30 years ago, now I've been retired six years. And they said, "Don't worry, we'll be with you." And slowly I would learn their clinical skills. And I've since been invited to and lectured at... I don't know, I would bet probably 30 different medical schools throughout my career. So I learned, first of all, becoming an accidental scientist that was never by design and then becoming an accidental clinician. 

 

[laughter] 

 

0:04:21.6 DM: But I'll finish off that story by saying that it was a wonderful synergy between the clinical world and my scientific world, because I would meet with the clinicians and we'd have a discussion afterwards, and I'd listen to what their challenges were. And if I couldn't answer their question, I just found my next research question for the lab. So, we went back and forth, and it was really a wonderful synergy. And I must say, I've had an absolute ball in my career. I've had fabulous mentors as a scientist. I've had fabulous mentors as a clinician. And I don't know, I have a feeling you're contacting me because I gave the keynote at the last fascia meetings at the International Fascia Meetings in Montreal. And it was a little bit of a homecoming for me, but to talk to all the fabulous bodyworkers that I'd worked with over the years, the Fredericks, Anne and Chris, Tom Myers, Robert Schleip. [laughter] All of these personalities that I just had an absolute ball with. And then I met a few new ones as well. 

 

0:05:39.9 DB: So, Dr. McGill, let's just dive right in. How do you go about identifying where back pain comes from?  

 

0:05:46.4 DM: Obviously, originally, I came more from the engineering side than the medical side. So I was trained in troubleshooting, from an engineering perspective, so it made sense to me. I started the experimental research clinic at the university close to 30 years ago now. And I started off the first appointment with a time of two hours. And my medical colleagues said to me, "Two hours? What are you going to do with a back pain patient for 2 hours?" And I said, "Well, the first thing I'm going to do is listen to them tell me their story," because I was doing pattern recognition. I was listening to activities that made them better and worse. I was listening to the nature of their pain and its character. I was listening to their past experiences with different types of clinicians, what made them better and what made them worse. 

 

0:06:41.4 DM: And we were able to create questions in follow-up that had a very high degree of validity. For example, if a patient said, "I have pain, I wake up with it and my right toe is numb. I get out of bed and the pain shifts to the left side of my back and then goes down my glute. In other words, the pain is migrating." That shows us that there is an element of joint instability. There is something experiencing micro movements, usually in a shear mode, usually because of injury or tissue strain the joint has become a bit lax or unstable. Then I would say, this is the high validity question and follow up, I'd say, "Do you ever have a sharp pain in your back or down your leg when you roll over in bed?" And if they say yes, that is tremendously indicative of the pain originating from a joint that has lost its structural normal stiffness. 

 

0:07:48.2 DM: So then I'm gonna focus in on that particular joint, and now we move to provocative testing. I'm going to provoke that joint to see if I can replicate the exact symptoms that the person is describing. If I can, I just found the target. Now the next task is to create the clinical antidote. And I might say, "Well, logic says that if the joint has lost stiffness, I'm going to add stiffness." So I might, ask them to put their fingers into their lateral obliques, push the fingers in, and now push the fingers out with an abdominal wall contraction. And they will either say, "Ah, now my pain is gone," doing the offensive move, whatever it happened to be. Or they might say the opposite, "Oh, my pain is worse." 

 

0:08:40.5 DM: Well, now we're testing tolerance because that muscular pattern that we were converging on to arrest the pain by supplying more additional stiffness was imposing a compressive penalty. So they didn't have compressive tolerance, so we have to find another stiffening program. I might ask them to... We tell a joke, "Are you old enough to remember hitchhiking?" "Good, externally rotate your thumbs at your sides and depress your shoulders down with your pecs and lats. Now let's repeat the shearing micro movement offense. Did that arrest your pain?" And they might say yes or no. But anyway, point is we then test the pain mechanism and then we try and migrate the pain. You migrate stress concentrations from one tissue to another with posture change and stiffness change. Movement hacks we might use, for example, tying their shoe a different way, etcetera. 

 

0:09:45.2 DM: And then I will review their imaging. My orthopedic colleagues, for example, typical practices, they put the images up on the view box or on the computer, and they declare what's wrong with the person or what tissue is the candidate mechanism. And we don't do that, we only use the images after we've done our provocative testing to confirm that, yes, in fact there is a anatomic reason. But I could give you an example with whiplash. One of the final studies that I did, at the university before I retired, we took a group of whiplashed people who... They were one to two years post car accident, and they were still continuing to have disabling neck pain. Every one of them was dismissed by the medical profession and accused of being pain malingerers or pain magnifiers because they still had symptoms and the medical profession agreed that, "Oh, well, those tissues should have healed after the year, therefore the pain is in your head." 

 

0:10:57.1 DM: Some of them had no real reason to justify their whiplash symptoms by looking at their images. But we then used video fluoroscopy, and you as manual therapist, bodyworkers often feel this in your hands. As the person moves their neck through the range of motion, they don't get pain at the end range of motion if it's an instability from a joint strain or a tissue strain or some tissue may even have torn with the whiplash insult. Instead, the symptom happens halfway through their range of motion. So we would take their necks through the range of motion. And it was so interesting that when they got the flash of pain we would see a particular joint in the neck clunk, it would shear just a millimeter or two, perfectly explaining a shot of pain that they were experiencing. 

 

0:12:03.0 DM: So, of course the MRI never gave the evidence, but the pain associated with that mechanical clunk that could only have been seen in a dynamic test. Now, I don't have the wise hands that my manual therapy colleagues do, so they will quite often feel this. And I brought this up at the fascia meetings, how I have learned from my clinical colleagues how to tighten up fascia and joints. For example, with those whiplashed people, we would start by saying, "Touch your teeth lightly together and retract your chin. Stand tall. Now push your tongue hard to the roof of the mouth," and they will feel the deep flexors activate in their neck, so we give them that feedback and perception. 

 

0:13:00.8 DM: And then we might say, "Grimace the corners of your face and cheeks downwards, adding more stiffness to the neck and then repeat the offense, go through the range of motion." And of course, you know the answer here, some immediately were able to do this pain-free, one repetition. Sometimes there may be a very little so expertly applied effort to target mobility to the joint above and the joint below perhaps, the adjacent syndrome, adjacent segment syndrome, where a little bit of stiffness is exacerbating the laxity causing pain in an adjacent joint. So you can see why once in a while I refer very specific patients to my manual therapy colleagues. But anyway, there's a little bit of a story on how we go about identifying very specific pain triggers, which then guide our intervention. 

 

0:14:15.3 KC: Oh, I love that. So fascinating to hear about the assessment and testing process. Let's shift gears a little bit, Dr. McGill. Back pain is often referred to as non-specific back pain or non-causal. And oftentimes we have clients come to us saying, "This is my diagnosis. Here we go." [chuckle] So let's talk a little bit about that. What do you feel about that? What does that term mean?  

 

0:14:36.2 DM: Yes. It's a very critical question. What it means to me is they've never had an assessment. Have you ever heard or seen a medical paper on non-specific leg pain or non-specific head pain or non-specific any kind of pain other than back pain?  

 

0:14:55.8 KC: Nope. 

 

0:14:56.6 DM: I haven't. It would be considered a joke. So as I will repeat again, it shows me that the person has not had a thorough assessment that has come up with a much more specific and precise description of what is causing their pain. Historically, non-specific back pain came from radiologists. They would never see the patient, they would only see the pictures. And if they couldn't see a reason for the pain, and I just described a very specific one with the whiplash example, they would then say, "Well, you've got non-specific pain. We don't see anything anatomically that would justify it." And then it spread throughout the various professions. The other great impediment of persisting with this idea of non-specific pain is people then study it. So you will see scientific papers on non-specific back pain. 

 

0:16:01.6 DM: Well, let's pretend we're doing one right now. We're going to take two groups... Sorry, we're gonna take... Let's keep the group non-homogeneous. We're gonna have a group of older people who their pain trigger is created by walking and it's relieved by sitting, and also in the same study is gonna be a group of young people who say, "No, no, I'm the opposite. Sitting in front of the computer for 20 minutes triggers my pain and going for a walk is relieving." So now let's do a macro statistical analysis on that non-homogeneous group. 

 

0:16:39.8 DM: You know what the answer is? On average, it makes no difference. Half are made worse with sitting, the other half are better with sitting. [chuckle] So on average the answer is zero. So let's get rid of this notion of non-specific back pain and let's make it specific. We're just going to create two categories, those who are triggered by sitting and those who are triggered by walking. Now, all of a sudden, the statistics show because we've satisfied the condition of group homogeneity, which as you know is the test of validity, before you even start a statistical analysis the groups must be homogeneous. So now of course, the statistics, which is just a weighing machine really, then show that their pain isn't specific. Those who are triggered by sitting have usually a flexion intolerance, probably more of a discogenic category. And then we'll follow them up. And the people who are having difficulty walking and are triggered are probably more later in life with more arthritic facet joint foraminal stenosis, etcetera, subcategories. Anyway, I hope that is a little bit of an essay of the great impediments expressed in many layers for those who persist with this idea of non-specific back pain. 

 

0:18:10.8 KC: Let's take a short break to hear a word from our sponsors. 

 

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0:18:56.0 KC: Let's get back to our conversation. 

 

0:18:58.4 DB: So, Dr. McGill, when does assessment begin when you're working with a client, and how long does it take you to understand the mechanism of their pain?  

 

0:19:08.3 DM: The assessment starts with the first contact that they send to me. It might be an email. I'm already doing an assessment in the email trying to understand their emotions, their desperateness, their feeling of alienation from the clinicians that they've seen who may have given them this non-specific back pain diagnosis or some have dismissed them or some have downright hurt them. So the assessment starts right then and there. 

 

0:19:41.6 DM: If they come to BackFitPro HQ here in Gravenhurst, Canada... On my clinical days, I only see one patient in the morning and one in the afternoon because I spend a lot of time with them. I watch them get out of their car and come up our driveway, so the assessment starts then. If they're a 7ft tall NBA center, they have to duck their head to get under our door threshold, I can see the pain quite often in their eyes as they look up. I then say, "Do you mind taking off your shoes? Let's go over here and we'll sit down." All the time I'm observing that, getting hypotheses as to what is causing their pain. Is it their behavior that all day long they're picking the scab and sensitizing their pain or are they savvy to the movement hacks? In other words, I ask everybody who comes here to read my book, "Back Mechanic" which is a collection of movement hacks that allow them to desensitize their pain first and foremost. 

 

0:20:47.9 DM: So to really answer your question specifically now, how long does it take? Well, the answer is it depends. Sometimes I know in two minutes, sometimes it might take me a few hours to do the testing. And I think of one patient, not that long ago, who you could do a slump test and nothing showed. And yet she said, "When I sit, and particularly when I drive, I can't stand the excruciating pain down my leg and in my back." So as it turned out, only as she extended her leg in that posture was the pain caused. And then I went back and looked at her MRIs and I found a Tarlov cyst on that nerve root, which the assessment said she doesn't have a disc bulge. The nerve isn't frictioned. There's something very peculiar that when you pull a nerve in one direction, that is the symptom. So it required a convergence on that, and then that became my directive, "There's something that I'm missing on the outlet of that nerve." And then we went and found the Tarlov cyst and I was able to refer her to a surgeon in Texas who specializes and has a fairly good track record on dealing with Tarlov cysts. So there is an example. Sometimes it's three hours. 

 

0:22:30.0 DM: Oh, I'll give you one more example. I had a serviceman come and see me from the US Air Force. And we were able to, within that session, identify his discogenic back pain. But he called back, as we do with a six-week follow-up, and he said, "I'm still... I got this grumpy back pain." And I probed him a little bit more, and then I said, "Have you ever been tested for Lyme disease?" And he paused and said, "No, why?" And I said, "Because that's the character that could account for these lingering aches." And sure enough, he tested positive, was treated for that. And in our six-month follow-up, he said that was... No one ever found that. So there is an example of, it could be one minute, we get a fairly tight convergence on the pain mechanism after two or three hours in the first session. But occasionally, it takes a bit more follow-up. 

 

0:23:38.4 KC: Dr. McGill, tell us a little bit more about virtual surgery. 

 

0:23:44.3 DM: Our research over the years strongly suggests that surgery in many cases works because it's forced rest. Now, the caveats to that is, of course, there's a whole chapter on "Back Mechanic" to guide the person as to whether they are a candidate for surgery and what... The approach to find out what their chance for a good outcome versus a bad outcome would be. So now let me give it a clinical scenario. Let's take a person, she's a young mom, 26 years of age, two young kids at home. She has a background in distance sport. She loves triathloning, does a few marathons and that kind of thing, so she very much feeds on the endurance exercise dose to keep her happy. She says, "Well, a big part of it is that it's my stress reliever." 

 

0:24:52.8 DM: Now I've given you that scenario. If I then am able to converge on that patient's pain mechanism and I say, "You have no chance to wind down your pain sensitivity if you continue to do 40 minutes on the elliptical every day. And her response will be, "Well, I can't do that, otherwise I will have this breakdown." And I'd say, "All right, off you go, have your surgery. Now, I hope you've confirmed that the surgeon's knife is going to cut that pain out." And now I'm starting to get their attention a little bit. And I say, "How about this? If you go and have the surgery tomorrow, you will not be 40 minutes on the elliptical. You're going to be laying in bed and you're going to get up and go for a pee every few hours, etcetera. In other words, you will be put into a situation of forced rest, then you will slowly get reintegrated back into some very light physical exposures and you're going to teach and stimulate your body to adapt. Now, wouldn't it be nice if we could do that without the surgery and rolling the dice, because the surgeon hasn't proved to you yet that his knife or her knife is going to cut out your pain." 

 

0:26:16.0 DB: Now, the statistics on effectiveness. In our research clinic at the university, when I started, we set out a few mandates. One was, we're going to follow up with every patient we ever see. We're the only clinic that I know that has done this, so I know exactly our score. So let's take the subcategory of patient who've been told, "You've tried everything. You've been to the massage therapist, the Rolfer, the chiropractor, the physical therapist, the neurologist, etcetera, etcetera. You failed. The last thing for you is surgery." If that's the category that they came to the university clinic with, we would then give them this experience of virtual surgery, forced rest, and then slowly rebuild and stimulate their body. And then in a two-year follow-up, 95% of them were able to avoid surgery and were glad that they did. So that's a statistic now on the outcome testing that. And I can stand by that. 

 

0:27:30.3 KC: Dr. McGill, let's talk about your book, "Back Mechanic." It helps consumers with back pain determine a specific cause and address it. And as you mentioned earlier, you include movement hacks to help in that process. Can you tell us a little bit more about the book and some movement hacks for our audience, our listeners?  

 

0:27:46.9 DM: Yes. I'd written a number of textbooks for my clinical colleagues, for medics and people who deal with clients with back pain. And a few lay people would get them and they'd say, "Oh man, this is a tough read, but it's... For the first time we're starting to understand the specificity of it all. Would you write a book for the lay public?" And a publisher came to me and said the same thing, "Would you write a book, but we want it for the lay public? But in order to sell, it's got to have the title, "Fix your back in three easy steps or five easy steps," whatever it is." And I said, "But that's a lie. It's not possible. First of all, pain is only a symptom with a multitude of causes. So we have to find their specific cause and address it." 

 

0:28:37.1 DM: So that was the genesis for writing "Back Mechanic" for the lay public. It was the hardest book I had ever written, Kristin. It took me a long time to find the balance between giving it medical scientific validity, but simple enough to still be consumable. And I went back and forth for about five years before I think we got it reasonably right. But anyway, it guides the reader through a self-assessment of their pain with some self-applied provocative tests so they can determine whether their pain is triggered by bending forward or bending back, or compression or shear or a specific activity, etcetera. So let's say tying their shoe was one of those activities or putting their socks on in the morning. They get out of bed and right away they trigger off their back pain struggling to get their socks on. So now they're gonna have a bad day. 

 

0:29:40.7 DM: So what we might do is show them instead of sitting on the chair by the door before you go out in the morning to put your shoes on, stand in front of the chair and put your foot up on the chair, sliding your foot in, and then do a lunge. Now, very specifically, if you can imagine this, let's put our left foot up on the chair and the right foot is your stance leg on the ground. Don't bend forward yet. Bend your stance leg, your right leg, taking your hips right down to the target, close to your heel. Let your left knee come way forward of the ankle. And now your hands are able to tie your shoe without triggering a back pain. 

 

0:30:35.8 DM: So there might be an example of a movement hack they don't trigger and they'll delay the usual time that the back pain becomes problematic throughout the day. Then we show them not only how to wind their pain down, now we rebuild their body strategically. So strategic mobility and strategic stability. Some people have back pain because of a stiffer hip. Now, your audience are experts at... Of creating more mobility in the hip. A few years ago... I did a podcast yesterday recalling back to... I was doing something with the National Hockey League and the professional hockey players. And at that time, designer jeans were very popular, if you could [chuckle] imagine these skin tight designer jeans. Well, these hockey players have massive thighs and legs, and they would come in with these massive thighs squished into these jeans and then they would sit down. The jeans were artificial hip stiffeners. 

 

0:31:48.1 DM: And so as they sat down, the stiff hips weren't moving properly and their spines had to round out because some part of their body [chuckle] had to flex but the jeans stole their hip mobility. Hockey is played in a bent-forward position. So they were already dosing that to the max, sitting forced in that position because of their tight jeans was a problem. So we ended up, "Wear looser pants, maybe pleated pants. And now the therapist has an ability to work on your hip mobility to save your back pain." So there's [chuckle] a little bit of a story working through the linkage, but these kinds of things are addressed in "Back Mechanic" to rebuild the person and build sufficient endurance, strength, power, mobility, stability, etcetera. 

 

0:32:43.2 DB: This has been an incredibly enlightening Podcast. I want to thank our guest today, Dr. Stuart McGill. For more information about his work, visit backfitpro.com. Thanks, Dr. McGill. And thanks, Kristin. 

 

0:32:56.4 DM: Well, I appreciate you two as well for all you do and all you do for your membership as well. Thanks so much. 

 

0:33:04.4 KC: Thank you so much, Dr. McGill, for this incredible conversation today and also for all of the work you've done to help practitioners learn how to assess and help their clients with back pain. We really appreciate it. 

 

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