Course Review: McGill 2 - Converging on a Precise Diagnosis

Last week I traveled to Trois-Rivières in Quebec, Canada to attend a seminar designed by Dr. Stu McGill, PhD on the assessment and diagnosis of back pain disorders. McGill is a professor of kinesiology/biomechanics at the University of Waterloo and has conducted literally decades worth of research on topics surrounding spinal biomechanics and the mechanisms surrounding low back injuries. He regularly receives visits from patients around the world with difficult cases of debilitating low back pain seeking his expertise and guidance in hopes to be relieved of their pain. He also consults with military, law enforcement, firefighters, occupational groups and professional athletes to help reduce and prevent work-related back pain that is particular to those populations. You can see his full CV here if you’d like to scroll through it, but mind you it’s 116 pages long.

Clearly an accomplished figure in the academic and research world, McGill is far from just a bookworm locked in an ivory tower and has been vocal about low back pain prevention and rehabilitation amongst powerlifters, weightlifters, mixed martial artists, CrossFit athletes, and strength training enthusiasts in general, working extensively with those communities. I was eager to take one of his courses and jumped at an opportunity to take McGill 2 (the second in his 3-part course series) when I saw it was being offered nearby-ish (I still had to fly from NYC to Montreal and then drive 90 minutes to Trois-Rivières). With McGill’s prolific research accomplishments and success in treating difficult cases from around the world, I was curious to see how I could learn from his approach and enhance my own treatment of patients with difficult low back pain problems, which are challenges I look forward facing in my practice. I also like to attend courses that help challenge my biases (such as PRI’s Myokinematic Restoration which I reviewed last year), and I wanted to see if delving into the details of spine biomechanics would influence my biopsychosocial approach to treating pain (more on that later).


Course Summary

Let’s cut to the chase. The course, entitled “Converging On a Precise Diagnosis” emphasizes the importance of precisely that--in order to effectively treat low back pain, McGill says one must address the specific cause of the injury mechanism. The course instructor (Dr. Edward Cambridge, one of McGill’s proteges) continually spoke of how there is no such thing as “non-specific back pain” which you constantly see on many physical therapy prescriptions. Deciding the diagnosis and subsequently treating the patient occurs primarily through reproducing the pain through various diagnostic movements and clusters of special tests followed by facilitating relatively pain-free progressive exercises towards “good” movement. In this context “good” refers to any healthy movements that help diminish pain and don’t exacerbate symptoms caused by the precise diagnosis.

It was then that I learned more about both McGill’s and Cambridge’s treatment model for low back pain patients, which I thought was unique as far as “traditional” models of healthcare goes. Appointments can last for as long as 3 hours, and patients are charged by the hour. The first 45 minutes or so consist of getting to know the patient: Talking to them about their history of pain, getting to know their personalities, observing intricacies about their physical behaviors, outlining their goals, reviewing their premorbid and current functional capacities and pretty much noting any details about how the pain has presented and affected their lives. Think about the most detailed subjective history a PT would ever take during an initial evaluation, with no stone left unturned.

The physical examination that was taught was similar to other evaluation approaches I’ve encountered in the past at least in terms of structure. The patient performs a variety of movements such as walking, arising from a seated position, touching their toes, squatting, arising from a supine position, rolling, etc. The observant clinician takes notes on anything that may give clues as to what joints or regions to examine in more detail. Specifically, lumbar spine and hip range of motion is assessed actively, passively and with end-range overpressure all with the goal of finding the specific movement or position that appears to reproduce the patient’s symptoms most easily. All relevant diagnostic special tests related to the lumbar spine are fair game and despite most having low sensitivity/specificity individually, when combined altogether with other aspects of the examination may serve as potentially helpful clues to the clinician.


My Thoughts

I was surprised that there was very little content on how pain science tied in with all of the presented material.  I also found some difficulty with the title of the course and one of its central tenets. Converging on a precise diagnosis in order to treat the underlying source of pain, to me is a bold claim. I agree that being as specific as possible when identifying pain triggers and selecting effective treatment interventions is essential, but how does one discern what precise structure is the source of pain? I mean sure, by discovering the forces, positions and movements that most demonstrably reproduce a patient’s symptoms, we can single out behaviors we want to modify in the patient, encourage movement in certain directions while temporarily discouraging it in others. Do we even need to know what structure and diagnosis is the culprit if we’ve created this gameplan to address these factors?

Especially when labeling a specific structure as the pain culprit may not be possible.

To me, herein lies the biggest beef between treatment models that rely largely on biomechanical principles to explain pain mechanisms versus biopsychosocial (BSP) models.

Last year I took Dr. Gregory Lehman’s course “Reconciling Pain with Biomechanics” (a course I highly recommend) which addressed many of the issues described above and as the name suggests, outlines an approach that takes into account spinal biomechanics and combines what we know about pain neuroscience to treat pain. A chiropractor (and physical therapist) himself, Lehman actually studied under Dr. McGill in his Occupational Biomechanics Laboratory at the University of Waterloo and has taught graduate level courses on spine biomechanics at the Canadian Memorial Chiropractic College. Knowing of his firsthand experience in McGill’s laboratory, I approached Lehman after the course and asked him what was potentially the most glaring thing that needed to be reconciled with McGill’s work on low back pain. In short, he told me that in a painful low back, we cannot discern with certainty which structure is the source of nociception that ultimately results in pain. To me, this makes a lot of sense when you think about what pain is and how complicated of a phenomenon it is. We can’t know which tissue (muscle, disc, facet joint, ligament, annular fiber, joint capsule) is the one that when disturbed, sends nociceptive signals to the brain which then creates an output of pain as a response to a perceived threat. You can’t just look at a herniated disc and assume that pain in the low back occurs as a result of that--if this were true, everybody with a herniated disc shown on an MRI would experience pain but we know this is not the case and that imaging is a poor indicator of pain presentation (1).

In a painful low back, we cannot discern with certainty which structure is the source of nociception that ultimately results in pain.


Taking this into account, for physical therapists to say that we need to find a precise diagnosis when we evaluate low back pain may not necessarily be true.



Final Thoughts and Takeaways

In my opinion determining the diagnosis and cause of pain as a result of either an annular tear, a herniated disc, an arthritic facet joint or some other structure isn’t always imperative. But even so, we’re still not throwing spinal biomechanics out the window. As a PT I still want to know if there’s an end plate fracture, a Grade IV spondylolisthesis, a pars interarticularis defect or certainly any red flags such as cancer which still guides my clinical decision-making process. This doesn’t change the fact that physical therapists are still clinical detectives during the evaluation process--as stated earlier, we’re still looking for pain triggers, what movements exacerbate/diminish pain and are guiding the patient through exercises that curb the pain response. We’re still creating load tolerance responsibly in the affected regions in a way that doesn’t reproduce their symptoms.

I definitely found the notion of a 3-hour long assessment to be interesting. Such a model could be suited for the frustrated patient who has experienced stubborn back pain for years, and perhaps who has received inadequate care from other health care providers who have glossed over the details mentioned in this post. The fact that “non-specific back pain” accounts for 90% of patients with low back pain is shocking (2), and I’m curious if the majority of individuals who have received such diagnoses have generic rehabilitation experiences that don’t take the time to examine all the important details.

“Non-specific back pain” accounts for 90% of patients with low back pain.


I don’t recall there being any content in the course regarding passive modalities nor manual therapy treatment. But this is a topic for another blog post some other day...

In a nutshell, the McGill “method” doesn’t necessarily involve novel concepts nor does it reinvent the wheel when it comes to treating back pain.  It emphasizes being observant, being a good listener, spending a significant amount of time with the patient and being as thorough as possible. In fact, it was emphasized multiple times during the course that the McGill “method” isn’t really a method or a new kind of treatment paradigm. It’s educating the patient on what triggers their pain and teaching them how to desensitize themselves to those triggers. It’s prescribing an exercise foundation to restore pain-free movement and functional mobility centered around the patient’s goals.

There you have it: Patient education. Pain desensitization strategies. Graded exercise and movement. If you’re a clinician, these should sound very familiar and should be the main tools with which you use to treat patients with low back pain. If they already are, you’ve got the same framework as arguably one of the most accomplished and sought-after experts in the world on treating low back pain. If you’re a patient who has experienced chronic low back pain, you don’t necessarily need to have a 3 hour-long evaluation but make sure your rehab professional is teaching you how to manage your pain, giving you purposeful movement that is specific to your particular pain presentation and showing you how to progress it.

 

Sources:

1) Deyo RA, Weinstein DO. Low Back Pain. N Engl J Med. 2001 Feb;344(5):363–70. PubMed #11172169.

2) Koes BW, van Tulder MW, Thomas S. Diagnosis and treatment of low back pain. BMJ 2006;332:1430–34.