by Dr. Jordan Duncan
One of the primary aims of healthcare in the 21st century is precision medicine. One definition of precision medicine, according to best-selling author Clayton Christensen in his book "The Innovator’s Prescription: A Disruptive Solution for Health Care," is personalized care that is able to be delivered at a lower cost. This is achieved when predictably effective treatments are applied to precise diagnoses, ultimately leading to improved outcomes.
Unbeknownst to many, when it comes to musculoskeletal pain, precision medicine is already here. Surprisingly, it doesn’t involve a new form of diagnostic imaging or a cutting-edge surgical technique. Instead, it begins with a question, one that I believe doctors will routinely be asking within the next 10 years.
That question is “Does this patient have a directional preference?”
Directional preference is the phenomenon where rapid and lasting improvements in symptoms, motion, strength, and/or function are made as a result of performing a very specific movement. Said another way, it’s a movement that applies beneficial loads to the pain-generating tissue.
If present, the directional preference becomes the patient’s primary treatment intervention.
The movement that elicits directional preference varies between people, and can only be determined through a simple assessment conducted by a healthcare provider adequately trained in the McKenzie Method.
An x-ray or MRI can’t tell you if you have a directional preference. Neither can standard orthopedic testing. The way to truly know is by having the patient move repeatedly in a standardized manner, and then determining if the behavior of their pain exhibits the unique characteristics consistent with directional preference.
Assessing for directional preference is an investigation, and in some instances, it can take several visits to conclude if it is present. This time and effort are a small price to pay, however, because if you have a directional preference, both you and your doctor would want to know. Here are a few reasons why.
Directional preference is highly prevalent in patients with musculoskeletal pain, and the outcomes are excellent when patients are treated with their directional preference
This was highlighted in a landmark study, titled "Does it Matter Which Exercise? A Randomised Control Trial of Exercise for Low Back Pain." It consisted of 312 low-back pain patients, with or without sciatica. After the assessment, it was determined that 230, or 74%, had a directional preference.
These 230 patients were randomly divided into three groups.
Group one received their directional preference exercise. This was either lumbar spine flexion, lumbar spine extension, or a lumbar spine movement in the lateral plane.
Group two received an exercise where they moved in the direction opposite of their directional preference. For example, if their directional preference was extension, they were given flexion.
Group three received generic stretches and exercises, no different than what you would receive from a typical doctor’s visit.
After only two weeks of exercise, the difference between these groups was striking.
95% of the patients in group one, who were given their specific directional preference exercise, were either better or completely resolved.
Only 23% of patients in group two, who were instructed to exercise opposite their directional preference, were either better or resolved.
Just 40% of the patients in group three, who simply performed generic stretches and exercises, were either better or resolved.
The results clearly showed why directional preference is precision medicine. When a predictably effective treatment was applied to a precise diagnosis, as was the case with group one, a positive outcome was achieved in 95% of the cases.
It should be noted that while this study consisted of patients with low back pain and sciatica, directional preference is also extremely common in patients with musculoskeletal complaints of the neck, mid-back, and extremities, and outcomes are just as favorable.
In several published articles, roughly 80% of the extremity pain patients who were assessed had a directional preference. Most of these patients even had a prior medical diagnosis from their primary care doctor or orthopedist. These included, but were certainly not limited to, tennis elbow, plantar fasciitis, knee osteoarthritis, hip bursitis, and shoulder impingement. Regardless of the diagnosis, these patients achieved excellent outcomes when they were treated exclusively with their directional preference exercise.
Directional preference can improve the selection criteria for costly and invasive procedures
We also know that patients who are deemed to be at the extreme end of the pain continuum, where an operation appears to be their only chance at recovery, can still have a directional preference.
Recent research has shown that 40% of people on a waitlist for knee replacement surgery, and 50% of people on a waitlist for lumbar disc surgery, had a directional preference. These patients did very well with their specific exercise and virtually all of them were removed from the surgical waitlist. It should be noted that every one of them would have likely been operated on had their directional preference never been discovered.
It is for this reason that two prominent and forward-thinking orthopedic surgeons, Ron Donelson, MD, and Todd Wetzel, MD, in a paper they wrote 20 years ago, concluded that once red flags are ruled out, low back pain patients should not be undergoing disc surgery of any type without first being given the opportunity to be evaluated for directional preference.
With the research that has been conducted on directional preference since then, I have no doubt that these surgeons would double down on their assertion and probably even include other forms of surgery as well.
Directional preference empowers the patient to treat their own pain
Perhaps the biggest benefit of knowing if a directional preference is present is that it enables the patient to treat themselves. The most effective person to treat pain is the one who owns it, especially when they can orchestrate their own recovery using a simple and highly effective movement.
When you are able to treat your own pain, you no longer have to rely on others to "fix you," which can create a costly and ongoing dependence on passive care. It is no surprise then, that the recurrence rate for musculoskeletal pain, as well as the overall cost of care, decreases dramatically when directional preference is discovered.
Now the only reason I use the timeframe of 10 years is that human beings, by nature, are resistant to change. Research has strongly encouraged us to assess patients for directional preference for decades, and the time will come when we will be forced to listen. With the burden of growing healthcare costs for musculoskeletal care, the increased utilization of invasive procedures, lower insurance reimbursements, and the rising rate of chronic pain hopefully this will be sooner than later.
Since directional preference is so common, and the treatment for it is so effective, every patient, regardless of their diagnosis, should be assessed for it. Two common responses from patients when their directional preference is found, are “I can’t believe it was this easy!” and “Why didn’t someone show me this a long time ago?” Sadly, most patients are never given this opportunity because no one asked the question. This is unfortunate, as they could be one movement away from dramatically turning their life around.
Dr. Jordan Duncan was born and raised in Kitsap County and graduated from the University of Western States in 2011 with a Doctor of Chiropractic Degree. He practices at Silverdale Sport and Spine. He is one of a small handful of chiropractors in Washington state to be credentialed in the McKenzie Method.
Reprinted with permission from Jordan Duncan DC.