Precision medicine for musculoskeletal pain

Last month I gave a presentation to the Silverdale Rotary on Precision Medicine for Musculoskeletal Pain. Here is a summary of that talk.

I was first introduced to the concept of precision medicine from the book The Innovator’s Prescription: A Disruptive Solution for Health Care, where bestselling author Clayton Christensen lays out a model for cutting costs and improving outcomes in healthcare. He states that precision medicine is achieved when “predictably effective treatments are applied to precise diagnoses, leading to improved outcomes.”

As it pertains to musculoskeletal pain, most people would think that precision medicine would be attained through advanced diagnostic imaging such as MRI. While technological advances have made it possible to accurately diagnose and treat serious pathologies such as fractures, cancer or infection, it doesn’t always translate to other musculoskeletal complaints.

For example, research has shown that imaging findings we once strongly correlated with symptoms routinely show up in people who have never had pain in that area. These findings include degenerative disc disease of the spine, partial rotator cuff tears of the shoulder and knee osteoarthritis.

The more we image asymptomatic people, the more we realize how difficult it is to differentiate painful vs. non-painful findings on imaging. So if imaging isn’t all that accurate in telling us if or why someone is in pain, how will it help us make precise treatment decisions?

Thankfully, an assessment process mirrors the definition of precision medicine. It can determine a specific subgroup of patients who respond well to a precise treatment, consistently leading to favorable outcomes. This assessment is called the McKenzie Method, and the subgroup of patients are those with a directional preference. Directional preference is defined as the phenomenon where rapid and lasting improvements in symptoms, motion and function are made as a result of performing a very precise movement.

A fascinating study demonstrated why directional preference fits the precision medicine model. Titled Does it Matter Which Exercise? A randomized controlled trial of Exercise for Low Back Pain, the study consisted of 312 patients with low back pain. Each received a McKenzie Method assessment,

finding that 230, or 74%, had a directional preference.

The directional preference patients were then randomly allocated to three treatment groups. The first received the specific movement that elicited directional preference, the second received a movement in the direction opposite their directional preference, and the third received evidence-based exercises that had nothing to do with their directional preference.

After two weeks, 95% of the patients in group one were better or resolved, compared to only 23% and 42% in groups two and three. Based on that

research, there is a right way to treat patients classified as having a directional preference. And according to the definition of precision medicine, we have a predictively effective treatment that follows a precise diagnosis, ultimately leading to favorable outcomes.

Thankfully, directional preference isn’t limited to those with low back pain. It is just as common in other areas of the spine, and even the extremity joints, and the outcomes are just as favorable.

With the burden of growing healthcare costs for musculoskeletal complaints, the increased utilization of invasive procedures, and the rising rate of chronic pain, the time is now to pay attention to this. It is the closest thing we have to precision medicine for most patients with musculoskeletal pain.

Dr. Jordan Duncan is from Kitsap County and writes a monthly online health column for Kitsap News Group. He is owner of Silverdale Sport & Spine.