Regional interdependence is a term coined by Wainner et al in an article published in 2007 and is defined as:
“The concept that seemingly unrelated impairments in a remote anatomical region may contribute to, or be associated with, the patient’s primary complaint.”
Now, this idea that parts of the body are interconnected has been in existence in Physiotherapy for decades. What has changed over this time is the understanding of how and why interconnectedness occurs and this likely influences the clinical reasoning behind why we might implement treatment remotely from an area of injury. Let me explain:
Twenty years ago, at the start of my career, physiotherapists focused on a biomechanical model that was based on specific segmental facilitation. The idea was, for example, that a joint in the neck could be dysfunctional and cause the regions distal to that joint to experience pain. Clinically, the way to use this as a treatment model was to palpate for mobility at a specific segmental level and implement treatment based on your findings at that specific joint. Findings that would guide treatment would include things such as peau d’orange with skin rolling, sweat changes and restricted mobility at the proximal joint. Although there may have been some value within this line of treatment, recent research has identified some massive flaws with this line of thinking. The facilitated segmental model neglected to incorporate the central nervous system and its role in the processing of information coming from the periphery. The model focused on the use of palpation as being an accurate way to identify pathology and other than one study performed 20 years ago(ref), there is significant research to suggest that palpation findings are generally poor(ref). The model also based its intervention on the application of force to a specific joint in a specific direction. There is now a body of evidence suggesting that our manual treatments are not nearly as specific as we once believed. In one study, manipulation of the lumbar spine aimed at a specific spinal segment was accurate to the joint only 50% of the time(ref). Even if it were accurate, does it matter? A trial found that clinician determined cervical spine manual treatment compared to randomly assigned cervical treatment found equally improved outcomes in both intervention groups when compared to controls over the short-term(ref).
If this old model has significant flaws in its methodology for clinical application, on what basis might regional interdependence be working? Does this alter our reasoning process for its utilization or, perhaps more importantly, the language we might use with our patients? Can this model be expanded upon to include more than just extremities and the spine to more fully encapsulate the entirety of a patient’s presentation? Do we need to throw out the baby with the bathwater?
On this blog we have discussed the concepts of uncertainty and complexity at length. If there was ever a shining example of the misuse of these ideas in physiotherapy, the extraordinarily complex and unproven models to explain when to implement distal treatments and why they work is all too common across manual and exercise therapy based interventions. For example, take the Primal Reflex Release Technique. No, I didn’t make this name up, it is a system for assessing and treating injuries that postulates that pain leads to an overstimulation of the bodies primal reflexes and this can be adjusted by tapping at these reflexes. In a video on their website, an assessment of neck pain includes checking the mobility of the nose to glide laterally and treatment consists of tapping reflexes to reboot the neural system. I can actually buy SOME of what is being suggested; rebooting the nervous system fits loosely with a pain sciences approach and describing manual therapy in a non biomechanical way fits some of my biases. Not so sure about the inter-rater reliability or validity of nose motion palpation for neck pain…
But here is the thing – I’m sure many people have likely benefitted, at least temporarily, from this treatment. What is less likely is that the treatment is working because of the theoretical basis of Primal Reflex Release Technique. A more plausible explanation could include things like neurophysiological effects, patient expectation of benefit from a confident clinician using gentle and reassuring touch or clinician expectation of recovery. There are a couple of dangers when using a model of reasoning such as this – a certain number of patients will walk away and begin to believe that their nose is out of alignment or some other type of nonsense. Equally concerning is that the patient fails to receive a treatment that is efficacious and promotes independence; instead they waste time and money on simple nonspecific effects that probably could be garnered from the Homer’s spinocylinder.
There are couple of commonalities to these therapies: They create their own language, are often trademarked, rely on testimonial evidence, promise dramatic results with minimal research and are driven by a word that rhymes with honey
There is a plethora of research on how proximal exercise or manual therapy can change pain elsewhere in the body and how pain in one location can cause changes in other areas. There are numerous examples in the literature of regional interdependence – a number of studies demonstrate that thoracic spine manipulation can significantly improve neck pain and disability. Cervical spine mobilizations create hypoalgesia and improved motor control at the elbow. Exercise interventions to the hip improve patellofemoral pain symptoms. Hip manual therapy and exercise interventions can help decrease pain and disability at the knee.
We also see that the reverse is true – an impairment in one region is correlated with an increased risk of other conditions. For example, athletes with a prior lower extremity injury are at higher risk for another injury anywhere in the chain; whiplash injuries decrease pain pressure thresholds throughout the body; patients presenting with dupeytren’s disease are more likely to get a frozen shoulder and carpal tunnel syndrome patients often have concurrent neck pain. These examples are by no means exhaustive but rather identify that we are dealing with a complex and inter-related system that should be viewed with a broad lens rather than a microscope. Regional interdependence serves as a reminder of this interconnectedness without attempting to explain why this occurs, because the truth is that we are far from fully understanding this system.
The even better:
Lacking in the original article published in 2007 was a recognition of psychosocial factors and how they influence clinical outcomes. Research consistently identifies that psychosocial variables identify patients who are at risk for poor outcomes with low back pain, shoulder surgery and whiplash to name just a few. Physiotherapy is moving away from minutia driven biomedical examination with limited evidence to support our clinical findings to using a biopsychosocial model to look at the whole person and the influences of not only physical impairments but also psychosocial variables. Sueki et al. addressed the problems with the original Wainner paper by expanding the regional interdependent model(ref). The authors suggest that this model allows clinicians to continue to use a biomedical model, particularly with red flag conditions, but also incorporate a neurophysiological and biopsychosocial model of clinical reasoning.
So, go ahead and treat areas remote from an injury – there is a slew of evidence to support both manual and exercise based interventions at distal regions. Even more importantly, use the idea of regional interdependence to step back and look at the whole individual and incorporate this into our treatment plan. But whatever you do, please question both the research evidence and scientific plausibility of many of these models of interconnected treatment – and just because you use one of these treatment models doesn’t mean you have to tell patients a crazy story to explain the cause of their pain and the treatment intervention. Instead, simply sing “The knee bones connected to the thigh bone…”. Scary that a children’s song does a better job of explaining regional interdependence than many of the models implemented in physiotherapy today…