MDT stands for Mechanical Diagnosis and Therapy, otherwise known as the McKenzie Method after its astute founder Robin McKenzie. The method was officially introduced in the 1980s, but was refined and developed over decades (since the '50s) after a chance sequence of events with a patient.
Originally starting as a way to assess and treat low back pain, it has since been effectively applied in the rest of the spine, as well as in extremity joints. There is now an entire McKenzie Institute, with instructors teaching the method internationally.
This system has peaked my interest for some time. My last clinical was at RIC's (now Shirley Ryan AbilityLab) Pain Management Center, where from a physical therapy standpoint, the MDT system was a cornerstone of evaluation and treatment. My colleagues at TSPT were also introduced to the method during their rotations and have since taken Parts A and B (lumbar and cervical/thoracic spine respectively). So for the last 2-3 years I have been experimenting with what I could glean from diluted variations of the method, with variable success (to be expected). This last weekend I attended the Part A seminar to get info from the source. Here are some of the key features of the method, that stood out after taking the course in person.
Systematic
So what is so special about this method? It is first and foremost a system of assessment. It provides the clinician with a systematic way of classifying a patient's symptoms and musculoskeletal impairments into categories.
There are 4 main categories: derangement, dysfunction, postural, and other - the details of which I will be covering in separate posts.
So rather than giving you a treatment tool (not knowing when, and more importantly when not to use/do something), the principles will guide the clinician (and patient) to create the treatment tool...
Boom. In my opinion this is the most powerful aspect of the method. As a rehab clinician, I am tasked with reducing symptoms and getting people moving better. However, that's never simple in practice. Pain can be cunning. At times it is consistent, but at others the complete opposite, and often unreliable in proportion to actual tissue damage (more to come on this in a separate post).
With a method to create treatment based on a classification, I can say:
"This presentation responds well to A, but very poorly with B"
"Based on the initial response, we may go to A2, A3, or A4"
"Once A has run it's course, we will do C"
It's an algorithm. I won't live or die by any particular exercise, movement, or other intervention because I will be able to select for appropriateness in various scenarios. "Never bend and load the spine" becomes "Temporarily limit certain movements if you present with x, y and z until you hit milestones 1, 2 and 3."
This brings me to important discussion points about back pain misconceptions.
(More) Myths about Back Pain
There are many back pain misconceptions and several of them are often linked with the MDT Method itself. Let's tackle these one by one.
Extension is Dangerous
It is not. For a long time it was believed (and to some extent still is) that extension of the spine should be completely avoided due to the mechanics of narrowing certain spaces in the spine. This is normal. There are rare scenarios where this motion can produce worsening neurological symptoms, which is an emergency situation. However, this is not exclusive to extension. It can happen with any spinal motion. It's not the motion that is dangerous but the response to the movement that can be alarming.
Flexion is Dangerous
Nope. Same logic, movements themselves aren't dangerous. Spine flexion is often blamed for low back pain. Kind of ironic how there are two common beliefs about the spine that are at complete opposite ends of the spectrum, huh? Maybe we'd be better off walking around with stiff trunks like robots...
Staying stiff, or neutral, is not a solution either. Hold any posture for long enough and it will get uncomfortable.
Sometimes flexion can be a relevant factor, but not always. In situations where it is, temporary modifications may need to be instituted until a recovery of flexion can occur without flaring up symptoms. It is a question of readiness for loading capacity, not right or wrong. The spine is meant to bend, flex, twist, etc. Valuable options that my friend in the garden above, does not have access to.
Herniated Discs Require Surgery
The human body has an amazing capacity to deal with stress and heal if provided with an appropriate environment and stimulus. In terms of MDT, something that is sought for is a directional preference to motion.
This is not exclusive to disc pathology, but is valuable to highlight here as disc problems have been stigmatized into "the conservatively untreatable" category. What directional preference means is that there is often a particular movement that can rapidly (over the course of a few days) reduce and abolish spine and radicular symptoms. Regardless of anatomical abnormalities seen on imaging.
So do discs need surgery to relief symptoms? The answer is: sometimes. Not nearly as often as occurs in practice. The times where it is appropriate is where conservative management has failed to positively change those symptoms or neurological signs worsen. But remember, not all conservative management is created equal. Without a classification system in place, interventions are thrown at a patient based on biased decision making. It is equivalent to shooting in the dark: sometimes you will get lucky. I don't want to count on being lucky.
Sciatica/Radiculopathy or Spinal Stenosis Require Surgery
Again sometimes, but not before failed conservative treatment in the absence of obvious, serious spinal pathology meaning severe and worsening neurological symptoms (Loss of reflexes, abnormal reflex responses, loss of bowel and/or bladder control, severe muscular weakness. Not necessarily pain). The MDT method indicates for a neurological screening in cases of radicular symptoms to assess if they can be changed with movement. The same concept applies to the neck and arms/hands.
Misconception about the MDT Method
It's Just Extension Exercises
This is commonly held within the PT profession itself. I was once a believer of this misconception. During my first clinical I was under the watch of a clinical instructor who had only taken one of the seminars and basically all they had taken from the seminar, was exactly this misconception. Every back patient got lumbar extension. No rhyme or reason as to when to use it, and when not to use it. At that time I thought it was all bogus, but that had been my only professional exposure to it at the time.
In fact there are no "McKenzie" exercises at all. As I indicated earlier on in the post, it is primarily a method of assessment. Through the process of assessment, the appropriate exercises are selected for based on the patient's response to the movements.
What to Keep in Mind
There is no standard treatment method in this system, only the assessment. The assessment is the bread and butter. If performed correctly the clinician should be guided towards fruitful pursuits, as well as which specific avenues to [temporarily] avoid. The appropriate treatment ought to reveal itself based on the patient's response to repeated motion.
If you are experiencing low back, neck, or extremity pain you may benefit from a mechanical evaluation to identify if a direction of preference exists.
I've got some more to say about MDT related topics but this post is long enough already. Stay tuned for more soon.
Thanks for reading,
Piotr