Making the Shift From Treating Dysfunction to Treating Sensitivity in Rehabilitation

Greg Lehman

Introduction

Treating individuals with pain is difficult. The emergence of pain from an individual is influenced by multiple factors, making pain a multidimensional problem. Pain can be viewed as the person’s response to perceived threat and its purpose is to motivate an action.¹ This definition is profound because it disconnects pain from merely being a response to tissue damage. Pain now becomes more about the sensitivity of the individual and how a multitude of factors interrelate to influence pain. When we recognize that numerous factors influence this sensitivity and the production of pain we can also acknowledge how numerous treatment approaches can be helpful.

Consistent with viewing pain as something that emerges from the individual and is meant to prompt a response, we can also view many physical dysfunctions in the same light. The assessment process of traditional musculoskeletal rehabilitation (with many approaches detailed in this textbook) attempts to identify physical impairments or presumed movement dysfunctions relative to a proposed ideal in our patients presenting with pain, those with recurrent injuries, and even those individuals who are pain free. The assumption is that impairments or assumed movement dysfunctions in the biomechanical realm either predispose one to pain/injury or perpetuate a painful problem. This is the cornerstone of the kinesiopathologic model of treating pain and injuries.

One limitation of the kinesiopathologic model is determining when an impairment is relevant or whether a proposed movement dysfunction is truly dysfunctional or merely is a manifestation of normal or even optimal variation. In order to identify movement dysfunctions, we must know what is ideal or normal. Assumed deviations from the ideal are presumed to be related to pain. It is a difficult task to conduct research in this area, and the research through the years has naturally been mixed. Even when we have research that might relate a specific movement pattern to pain or injury, we are left with clinically important questions:

Is this assumed movement dysfunction relevant under all conditions (e.g., high speed, high loads, different sexes, different contexts)?
Is the assumed movement dysfunction a cause or consequence of pain?
Is the assumed dysfunction merely a product of the normal variability of the motor system?
Must the movement dysfunction be changed to influence pain and injury?

The purpose of this chapter is to provide an alternative or complementary approach to the kinesiopathologic model. It is recognized that biomechanical movement patterns (simply biomechanics for short) are involved in many pain cases while at the same time recognizing that biomechanics is often completely irrelevant. Alternatively, we can change our view of assumed faulty movement patterns to movements that have merely become sensitized and pain-related rather than inherently dysfunctional. When movements or activities are viewed as sensitized or pain-coupled,² we have a number of different interventions to address these sensitivities. Therapeutic neuroscience education (i.e., pain science) and an exercise- and movement-based intervention can be used together with some changes in how the traditional approach is applied.

This chapter will have two related sections:

The point of pain science: the key messages of therapeutic neuroscience education
When biomechanics matters: highlighting the role of biomechanics within the biopsychosocial framework of pain and injury rehabilitation

Clinical vignettes will be used to illustrate examples throughout the text.

Part I: The Point of Pain Science

Therapeutic neuroscience education (i.e., pain science) can be viewed as a separate and distinct component of an overall rehabilitation approach or can be woven into different aspects of a multidimensional treatment approach. Examples of the former being those researched and taught by the Neuro Orthopaedic Institute (Explain Pain, NOI Group), Therapeutic Neuroscience Education researched heavily by Adrian Louw³ and Jo Nijs.⁴ The educational content of pain science education can be delivered separately or in conjunction with other treatment. Moseley and Butler⁵ state, “It presents the biological information that justifies a biopsychosocial approach to rehabilitation.”

A slightly different approach will use the key messages of pain science education within a multidimensional treatment approach. This approach may see less emphasis on structured education into the
neurophysiology of pain but will use the concepts of pain science throughout the clinical encounter. Two examples being the Cognitive Functional Therapy approach to rehabilitation⁶ and the Progressive Goal Attainment Program.⁷^,⁸ Both programs recognize that multiple factors contribute to pain; therefore, addressing the biopsychosocial interplay is helpful to influence pain and disability. These management strategies use pain science explanations to reconceptualize both pain and injury to ultimately change how patients view their condition to motivate and support change in their behavior. Pain science education could be used to encourage physical activity, address fears of reinjury, change catastrophizing, and explain the mechanisms behind and the factors influencing a patient’s pain.

These approaches may differ in how they structure and teach pain science, but they have many similarities that can be seen in the key messages delivered to patients and perhaps in their most basic therapeutic goals. Consistent across these approaches is the change in the meaning of pain to patients. Key messages of pain science will be explored later. The key message will be described and examples of how this influences therapy and function will be discussed.

Key Message: Pain Is an Alarm That Is Meant to Motivate an Action

Pain is an emergent property of the brain of the person in pain.⁹ Hodges and Smeets¹⁰ state, “When pain is acute the nervous system takes action to remove real or anticipated threat to the tissues and this can be achieved by motor output … When pain is chronic the motor system changes and its relevance for ‘protection’ of tissues is less clear.” Moseley and Butler⁵ eloquently and simple state, “EP (Explain Pain) emphasizes that any credible evidence of danger to body tissue can increase pain and any credible evidence of safety to body tissue can decrease pain.” This statement captures the multidimensional nature of the persistence of pain and illustrates how multiple interventions can be of benefit.

What This Permits Viewing pain as an alarm meant to motivate an action permits multiple lines of discussion that can influence behavior change and change how the patient perceives their condition. An alarm is not an indication of damage but is merely a response to a potential threat. The sensitivity of alarms is also not related to the degree of the problem that an alarm is meant to alert us to. This key message allows the therapist to introduce the idea that sensitivity is influenced by multiple factors in a patient’s life and therefore the amount of the alarm (i.e., pain) is also influenced by these factors. Sensitivity can also be changed. Recognizing this bioplasticity and adaptability gives hope but also sets timelines on prognosis for recovery.

Common discussion threads to introduce this to your patient are rhetorical questions about fire alarms. What causes a fire alarm to go off? Does the location of the smoke alarm correlate with the location of a fire? Does the alarm mean there is a fire? If a sprinkler goes off in one part of the building, does that mean that there is a fire there? Sprinklers going off at a distant are analogous to changes in muscle activity, muscle strength, weakness, etc., at a distance from the pain. All of these physical changes/impairments can be viewed as similar outputs from the brain/person in as much as pain is an emergent property. This helps reconceptualize impairments as possibly occurring because of the same need for protection or perceived threat as pain itself rather than some inherent flaw in the person.

Key Message: Multiple Factors Influence the Sensitivity of the Alarm

Related to the first key message is that pain is multifactorial. All aspects of a person’s life can influence their sensitivity and pain. For example, catastrophizing, fear of movement, expectations, psychological distress, and stress can influence pain and injury (see Fig. 15.1).

Figure 15.1 Pain is multidimensional. It is ultimately created by the person in response to a number of factors.

What This Permits It is not easy being a musculoskeletal therapist and asking questions that have psychosocial expectations. Many patients do not expect this of therapists and may not understand why the questions are being asked. When pain is explained as something that is influenced by many factors and is more than just tissue damage, then questions like these can begin to be justified. This can build a therapeutic alliance and can also influence recovery.

Key Message: Hurt Does Not Equal Harm

The belief that pain equals tissue damage is pervasive. The belief that structural and degenerative changes found on imaging may impact the pain severity of many patients. Yet, it is well established that there is an inconsistent and often poor relationship between many imaging findings and pain. Degenerative changes,¹¹ shoulder labral tears,¹² and disk herniations¹³ are consistently seen in asymptomatic populations. Further, even when tissue injury or inflammation appears to be linked with pain, there is no strong relationship between the amount of pain someone feels and the amount of tissue damage.¹⁴

This disconnect can be best illustrated to patients with simple questions about their past experiences with pain. Asking about the pain they felt during a paper cut and how that correlated with damage is useful. Asking questions about the variability in their pain throughout a day or over the course of the week helps illustrate how pain changes faster than we would expect tissue damage to change. A simple example is asking whether they think a fractured bone that is set in a cast for more than a week is painful. The patient will usually reply that they believe it is not painful, yet they will also realize that the bone is still fractured. Highlighting the discrepancy between pain and damage helps facilitate this change in viewpoint.

What This Permits This is a start to reconceptualizing pain and changing how the person perceives their condition. This in and of itself can influence the perception of threat or danger and may even influence physical function.³ Further, it can allow patients to perform activities or exercise that are painful. If pain is viewed as something that is not causing further damage, this allows for the addition of more meaningful activities. This is not to say that pain is ignored. Rather it is accepted and the patient can start to tolerate more activity either with less pain or the same amount. The caveat being that there is an attempt to avoid an exacerbation of symptoms or large flare-ups in pain the next day.⁵

Key Message: The Person Adapts to Applied Stress

Fundamentally, treatment can be viewed as the application of stressors to the person in pain. Exercise, activities of daily living, resuming work activities, and even cognitive stressors like pain science education can catalyze reactions or adaptation in the person. With acute injuries applying load to an injured tissue or a reactive tendon facilitates healing and repair. In the patient with persistent pain the exposure to feared or painful activities in a slow graded manner can increase the tolerance to those activities. Ideally, the exposure to those activities is preceded by pain science education which prepares the patient to perform activities they might view as threatening.¹⁵ Pain science education mitigates this threat and can change patients’ views about the danger associated with resuming meaningful activities or exercise.

What This Permits Very simply, recognizing that people have the ability to adapt allows or gives “permission” to start doing the things that they have been missing in their life. Exercise can function as an analgesic¹⁰ and preparing a patient with pain science education can help permit the resumption of exercise. Recognizing that the body adapts can also shift expectations and beliefs about structural influences on pain. It is possible that patients might worry about normal variations in structure (e.g., scoliosis, uneven shoulders, leg length inequality) and feel that these normal variations are driving their pain and must be corrected to be pain free. However, if there is a shift in thinking that the person can adapt, then a change in how a patient views the structural variants can occur. Further key messages can be seen in Figures 15.2 and 15.3.

Part II: When Biomechanics Matter

Simply, biomechanics might always matter to some extent in the prevention and treatment of pain and injury. It is just a question of what mechanical aspects need to be addressed and how much they contribute to the patient’s presentation. For this chapter, biomechanics refers to the BIO aspect of biopsychosocial model of pain and injury. Biomechanics is the study of the forces which act on, and are produced by, the body. Relevant topics to pain and injury are the kinematics or “quality” of movement/technique, forces and loads on the body, the strength or resiliency of tissue, and/or the physical impairments/functional abilities of individuals.

Figure 15.2 Key message overview part I.

The following sections propose potential areas where the biomechanics component of the biopsychosocial model can be viewed as a relevant area to address. This approach recognizes that biomechanics is just one part of multidimensional treatment, but for the sake of brevity, the focus is on the mechanical aspects of rehabilitation. It should also be noted that the presented approach is an alternative and/or overlaps with other mechanical approaches to treating pain and injury. This does not mean that those other approaches are not valuable or effective. It is merely a different route and means of interpreting how common physical findings relate to the patient in pain.

Five areas will be presented where biomechanics contribute to pain and injury and where modifying biomechanics may be of benefit in the prevention and treatment of pain and injury. Case vignettes will be used to illustrate the concepts for each category. It is recognized that these categories are fluid and even overlapping. Other categories or means of classifying may also exist. For the purpose of this chapter, mechanics are viewed as relevant in the following areas: