A Conversation with the Preeminent Lumbar Spine Researcher: Stuart McGill, PhD.
By William Morgan, DC
If you keep up with the latest scientific research articles about the spine, then you have undoubtedly perused some of Dr. Stuart McGill’s work. If you have not run across the name of Stuart McGill, PhD, then I am excited to introduce him. He is one of the most prolific lumbar spine researchers of our age. With more than 300 peer-reviewed publications to his credit, he has spent three decades asking and answering deeply rooted questions about how the spine functions. Stu and I became friends in 2007 when I first sought him out as I became the chiropractic consultant to the White House.
We have remained in contact for these many years, sharing thoughts on spinal mechanics and clinical presentations. Of late, McGill retired from the University of Waterloo, where he was a professor for 32 years and chair of the Department of Kinesiology for many of those years. Now he lives in the picturesque hamlet of Gravenhurst, Ontario, the town where many of his wife’s’ family live. Happily situated in retirement, he no longer performs the high-level research for which he is famous, but he is able to engage in his favorite pursuits as an avid outdoorsman.
He is still a much sought-after expert in spinal dysfunction and has clients from around the globe visiting his rural, often snow-covered home and clinical lab. During my recent visit with Dr. McGill, we engaged in several hours of conversation. We videotaped it all because I am elated to present both the personality and thoughts of my iconic friend. What follows is an unabridged portion of our transcript.
“Back pain is highly specific. It’s a very non-homogenous condition, so it demands that it be assessed to figure out what the very precise cause of that back pain is.”
The American Chiropractor I FEBRUARY 2019 INTERVIEW
W. Morgan: Hello, this is Bill Morgan, president of Parker University, and I’m here with Dr. Stu McGill, a world-renowned scientist, and comedian, at his home in Canada. Thanks for having us, Stu.
S. McGill: Well, it’s my pleasure, Bill. Welcome to Gravenhurst. I wish we had a little bit better weather for you. Last week, it was minus 23, and I was hoping for that. I think we’re just a degree or two below freezing, but welcome, once again. Fabulous to have you here.
W. Morgan: Thank you, we’re a little heartbroken that it’s not 23 below freezing, but there’s plenty of snow out there for us. Glad to be here. I’d like to talk about our favorite subject, which is the spine—the lumbar spine. We’ve talked a little bit about nonspecific lower back pain, how that’s affected the world, and how we put so much research into nonspecific back pain. What’s your opinion on that?
S. McGill: Well, this could be an hour discussion, but basically, to me, there’s no such thing as nonspecific back pain. Have you ever heard of nonspecific leg pain? Can you imagine someone coming to a clinic and saying, “I’ve got nonspecific leg pain!” The clinician fails to assess it further, so they haven’t a clue whether it’s a fracture, an infection, a hangnail, a skin disease, or what. Exactly the same situation covers back pain. Back pain is highly specific. It’s a very non-homogenous condition, so it demands that it be assessed to figure out what the very precise cause of that back pain is. Once that is understood, you have a roadmap to direct you toward what that person needs to do to eliminate the cause of their back pain. Then, what do they need to do to build the foundation in this linkage to be able to perform activities pain-free?
So that’s my thought on it. All these randomized, controlled trials on nonspecific back pain compare exercise to chiropractic to physical therapy. Then at the end, they conclude either nothing works, or everything works. It’s a waste of effort. If they can sub-categorize the back pain mechanism, they’re able to match specific therapeutic approaches with specific mechanisms of pain. The efficacy goes way up, and I would even take that a step further. Combine that with clinical mastery.
W. Morgan: So, you are pretty confident that you can isolate the nonspecific back pain down to the specific pain generator and then address that?
S. McGill: In most patients, absolutely yes. Not in all, but in most. It’s a combination of listening to their story and recognizing patterns. When that leg pain patient comes in, if the clinician can’t listen to their story and recognize the pattern to determine if they have a torn ACL or a vascular claudication in their leg, he or she must stop and go get another job. They’re not competent. So, in back pain, I listen to the story to recognize the patterns. Then I go and test them by using different combinations of motions, postures, and loads, which imitates the stress from different load-bearing tissues. We stress different nerve roots, etc., and keep honing it down. Then at the very end of all of this, we have our hypothesis of what the pain is; we’ve eliminated the suspect alternatives. We also know what the pain isn’t; that’s all part of it. Then we can predict what is going to be seen as a feature on a medical image. Now we have context for interpreting what we see on the image. When you finally put all of this together, a master clinician will come up with understanding the full pathway of pain mechanism.
W. Morgan: Currently, some in the “evidence-based” camp of spine care providers tell us that X-rays and MRIs are not only not useful, but you also should avoid them at all costs. You shouldn’t do advanced imagery, you shouldn’t do X-rays, and you shouldn’t do any advanced diagnostic procedures. Instead, you should focus on cognitive reasoning. Where do images fit in? Where do advanced diagnostic studies fit into the world of clinical practice?
S. McGill: Well, I certainly am sympathetic to the position of the overuse of MRIs and the inability—this is a bit of an indictment—of many radiologists to see the mechanism of tissue damage. When they use the word degenerative disc disease, I put that in the same category as nonspecific back pain. It’s a garbage term. In every person who comes here with the diagnosis of degenerative disc disease, we can hone it down so much more. Is there history of end plate fracture? Schmorl’s nodes? Or type 1 Modic changes, which is an inflammatory response to a nucleus that is breached through a small fracture into the vertebrae. This whole story is there for you to see, if you can interpret it. However, over time, that pain will burn out. We’ve seen this many times where the nasty-looking joint with bone spurs—you can tell that it’s not a new injury—is not the pain source. It might be two layers above, which is now taking the brunt of the motion responsibility. That might be where the pain is from, and we measure that clinically in our exam. But the image, in my world of people who have failed several layers of clinical approaches. is quite often very important. We talked earlier about some of the interesting nerve traps and drags, as I like to call them. So, as people move, the nerve roots floss back and forth. At the other end of the spectrum are the clinicians who see fresh back pain patients, and I’ll agree, the image is probably not necessary on the first visit. If they are clever, they will figure out the offending motions, postures, and loads, mitigate those, and coach movement patterns and strategies to avoid the stress that is caused by those specific provocations.
Additional Insight These are just some snippets of my many hours of conversations with Stuart McGill, PhD. You can learn more by seeing him live in Las Vegas at the 2019 Parker Las Vegas Seminars or by seeing videos of these conversations through Parker University’s website—parker.edu. My dialogues with Dr. McGill uncovered several themes in his thinking, and I am happy to share my interpretations and thoughts. There are master clinicians in various professions, and there are inferior clinicians in all professions. It takes concerted effort, diligence, focus, mental discipline, and plain hard work to become a master. Lifelong learning and an open mind are required to attain mastery in any endeavor. Imagery such as X-rays and MRIs should be used as a tool, not a crutch. It is often the medical gatekeeper, usually a family practice or internal medicine physician with minimal musculoskeletal training, who takes X-rays and MRIs as a screening tool. This results in elevating the diagnosis and heightening the anxiety of the patient. This is especially true if the provider lacks the ability to place the findings into clinical context. This may even interfere with construing the correct diagnosis and treatment regime.
Taking X-rays or MRIs is not inherently bad. However, when they are taken without indication and the findings are presented to patients in an inappropriate manner, it may result in the imagery interfering with care. Overemphasizing incidental findings to patients on imagery can lead to catastrophizing of their condition. They may view themselves as frail and unable to recover. Pursue specificity. On this topic, I am sure that most chiropractors would agree with Dr. McGill. We attempt to identify a specific fixation, lesion, provocative movements, causation, and correction. Our adjustments are called adjustments because we seek to be specific. Chiropractors seek specific treatments for specific conditions. “It depends…” Finally, Dr. McGill is well known for prefixing answers to clinical questions with his trademark answer, “It depends.” This is probably the biggest take-home message for me. There are no absolute answers. It always depends on many factors. Every patient is unique, and we must labor to create a specific treatment plan that depends on what we see in that particular patient.