Guest Post! All About Pain by Dr. Joe Brence, DPT

Dr. Joseph Brence is a physical therapist practicing in Pittsburgh, Pa.  When he is not busy treating patients, he is  involved in several, large clinical research projects.  His interest is to further determine “how stuff works” and has a large interest in the brains involvement in the pain experience as well as the neurophysiological effects of manual therapy techniques. 

Joseph is also married to his wonderful wife, Kristen, has a Boston terrier named Ellie, and enjoys exploring the south hills of Pittsburgh with them.  To read more from Joseph, visit www.forwardthinkingpt.com

By: Joseph Brence, DPT (@joebrence9)

Recently, there has been a lot of discussion in the “PT community” about approaching the care of painful conditions from a biopsychosocial approach vs. the typical biomedical approach. These two methods differ theoretically and Dr. Religioso has graciously asked if I would contribute a guest post on the treatment of pain from a biopsychosocial approach. I hope after reading this article, we could engage in a fruitful discussion about what we do, why we think it works and what science is telling us about how it works.

Step 1: What is pain?

The International Association for the Study of Pain (IASP) defines pain as “An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.”¹ This definition highlights, in one sentence, one of the most essential things we must understand about pain when treating our patients …nociception (which is input from nociceptors—unmylenated, danger receptors) is not necessary for the experience of pain. Pain is 100% of the time an output from the brain based upon many different variables, and simply the brain’s suspicion that a tissue has the potential for damage, will cause it to react. This reaction results in a conscious experience, which is crucial for our safety and survival.² The brain’s reaction can be based off of an interpretation of sensory input from the body, previous experiences of pain, social and/or environmental influences, expectations of consequences of the threat, beliefs/logic, etc. The reaction by the brain is based off its interpretation of the idea, “how dangerous is this threat?” If the brain determines the threat has potential to harm the body, it will send pain to that area, to protect.³ This sensory experience causes us to react and defend our tissues. It causes us to pull our hand away from a hot stove and unknowingly assume postures and change positions in order to preserve the integrity of our tissues.

Step 2: How do we understand how our patient is experiencing pain?

As PTs, we like classification systems to describe to our patients why they hurt. Under a biomedical model, we typically consider pain as acute, subacute or chronic and base our understanding off of a time-frame. We also like to classify the pain based upon the affected tissue and will describe it as fascial, joint, muscular, visceral or nerve (more about this later). Because of the unpredictable nature of painful conditions, and the poor reliability associated with attempting to determine what tissue hurts, I suggest we instead begin utilizing a classification of pain according to their neurophysiological principles. This approach has been determined to have discriminative validity⁴ and is better supported by the current neurophysiological evidence. It states that pain can be classified as:

1. Nociceptive:

• intermittent and sharp with movement or mechanical provocation
• pain localized to the area of injury or dysfunction
• clear, proportionate mechanical/anatomical nature to aggravating and easing factors
• pain described as shooting, burning, sharp, electric-like
• pain in association with other dysesthesias
• night pain/disturbed sleep
• antalgic postures/movements

2. Peripheral Neuropathic

• history of nerve injury, pathology or mechanical compromise
• pain in a dermatomal or cutaneous distribution
• pain/symptoms provocation with movement tests that move or compress neural tissue (ex. SLR)

3. Central Sensitization:

• pain is disproportionate to the nature or extent of injury/pathology
• disproportionate, non-mechanical, unpredictable pattern of pain provocation in response to aggravating/easing factors
• strong association with maladaptive psychological factors
• diffuse/non-anatomic areas of pain/tenderness to palpation
• hypersensitivity to peripheral stimuli (thermal, tactile, sharp/dull)

In the understanding of this classification, we must consider that most tissue injuries take a certain length of time to heal. When a tissue is damaged, an output of pain can occur to protect it (this leads to an adaptation within the pain pathways). The longer the nervous system reacts to protect the tissue that is supposedly damaged, the more efficient it becomes at sending an output of pain to protect that region. This causes the nervous system to become more “sensitive” and in some cases, simply the suspicion that a tissue is in danger will cause it to react.

Ultimately, a prolonged output of pain can result in a process called central sensitization. Central sensitization occurs due to an augmentation of responsiveness of central neurons to input from unimodel and polymodal nociceptors. This leads to an altered sensory processing within the brain, malfunctioning of anti-descending nociceptive mechanisms, increased activity of pain facilitory pathways, temporal summation and long-term potentiation of neuronal synapsis in the anterior cingulated cortex. This results in a central process of an increased responsiveness to peripheral stimuli, even if they are non-threatening.⁵

We must understand that this process occurs. Our patients, who we once classified as having chronic or difficult low back pain symptoms, may have not had pain because their spine was unstable, hypomobile, or arthritic, but instead because a central sensitization of the nervous system has occurred.

Step 3: What is the biopsychosocial approach to treating pain?

Moving past the neuroanatomy of pain, we must also understand that pain does not simply occur due to the tissues of our body but instead because of an even more complex relationship that exists between the biological (anatomical and physiological), psychological and social factors that occur concomitantly in many conditions. This understanding leads us to treatment patterns using a biopsychosocial model.

There has been significant evidence to support that non-anatomical variables can serve as prognostic indicators as well as obstacles to recovery, in many of the patients that we see.⁶ For example, a recent study, published in the Journal of Pain, found that pain catastrophizing, pain-related fear of movement, and depression predicted pain and function one-year following total knee arthroplasty (TKA). This study demonstrated that the prognostic indicators, for those who will have long-term pain following a TKA, appears to be correlated with psychological variables.⁷

As PTs, we must understand that painful conditions may not always be related to the tissues of our body, but instead a complex interaction of internal and external variables.

Step 4: How do we incorporate this knowledge into effective treatment?

I believe the best way to incorporate these concepts into practice is to: 1. understand our diagnostic limitations 2. utilize pain education 3. incorporate graded exposure for the treatment of pain 4. understand what happens when we touch our patients and 5. never provoke pain. These concepts may not change your interventions per se, but will instead change your rationale for when to use them and why you think they are working.

1) Understand our diagnostic limitations. As PTs, we often like to blame specific tissues for our patient’s pain. We will tell them that their pain is due to a strained muscle, restricted fascia, a slipped disc, etc. but how truthful are we being in these statements (you don’t have to admit this out loud, just think about it)? Many of our palpatory tests are unreliable and unless we are utilizing diagnostic imaging (which has its own limitations), how do we know what exactly we are touching, besides the skin, and how we can be sure that what we think we are touching is causing our patients pain. I recommend instead, classifying each patient’s condition utilizing the criteria I detailed above and approach treatment with an understanding of each class. For example, if the patient is in a process of central sensitization, research indicates they are hypersensitive to thermal stimuli. So application of hot/cold modalities may actually lead to an increased pain output and be more detrimental than beneficial. Classifying pain in these three groups can help us formulate a more scientific plan of care.

2) Utilize pain education and incorporate them into the care. If we want to truly be called “Doctors of Physical Therapy”, we must educate every one of our consumers… plain and simple. The term doctor is actually derived from the latin term doctoris which means teacher. Literature is indicating that there is a significant value in the education of healthcare consumers about “pain.” By teaching our patients that multiple variables can influence their pain, such as the context in which they experience it, will help them understand why other past interventions may have been unsuccessful. In this process, we actually may have to “undo” some of the education we have previously provided, but in doing this, we will be more evidence-based, honest clinicians and I guarantee most patients will respect and appreciate this. I recommend reading more about this in this piece by Dr. Lorimer Moseley.

3) Incorporate graded exposure in the treatment of pain

Graded exposure is the exposing of a patient to a specific situation which they are fearful. This exposure is gradual and hierarchical, in which you introduce an exercise or activity which elicits very little fear and gradually introduce more fearful situations. Evidence supports this in the reduction of pain-related fear and disability.⁸

To begin with graded exposure, I generally utilize a patient specific functional scale, Tampa scale for kinesiophobia, FABQ, etc. to look at situations which my patient perceives as threatening. Exercises and goals are then designed to gradually perform activities which they they were unable to do due to fear.

For example, let’s say we have a patient who has complaints of back pain one year after a lifting injury (It was injured when they attempted to carry a 50lb crate up a ramp). We would begin graded exposure treatment by having the patient actively assume positions necessary to lift a crate. We would progress the patient by moving into these positions while visually looking at the crate followed by lifting of an empty crate. Eventually, we would add weight to this crate and have them carry it on a level surface and progress to doing so up a ramp. In this case, the patient was able to approach the task in which the brain perceives as threatening and gradually work to overcome the fear. This approach is much different than having the patient perform pelvic tilts until their core is stable.

4) Understand what happens when we touch our patients

Manual therapy is extremely important to our profession and patient care, but this stated, I think we must understand our limitations of understanding how it works. Because this is “The Manual Therapist’s” blog, I do not want to go into great deal with this subject, but want to say that modern neuroscience does support interhuman interactions (so if you have a method of manual therapy that makes sense in regards to modern neuroscience, use it). Whether the effects are biomechanical, neurophysiological, or placebo (there is a wide range of literature to support all three of these notions---most recent literature pointing to the latter two) my only recommendation is that we do not perform techniques which the patient perceives as threatening or limits their expectations for recovery. Quite simply, we shouldn’t poke at something that hurts but instead only help the patient move a restricted body part within their pain limits.

5) Do not provoke pain

This is a simple principle to understand. Current evidence does not support the phrase, “no pain, no gain.” We must attempt not to push our patients into pain, because as described above, the more afferent nociception that occurs, the more sensitive the nervous system can become, which can lead to central sensitivity. We must be conscious that pain is a defense mechanism and if our patients complain that we are making them do something that hurts, we must back off.

Summary: In summary, I have highlighted how we can incorporate modern neuroscience into a biopsychosocial model in the treatment of our patient’s painful conditions. Pain is the costliest condition for our modern US healthcare system and we must admit, none of us hold the “holy grail” knowledge or intervention at eliminating all of our patient’s pain. I believe if we take into account what science is telling us, we can ultimately do a better job with patients who may have not gotten better in the past.


edit: Here is my response.

References

1. Merskey H, Bogduk N. Classification of Chronic Pain. 2nd ed. Seattle: IASP; 1994
2. Iannetti GD, Mouraux A. From the neuromatrix to the pain matrix (and back). Exp Brain Res 2010; 205; 1-12
3. Moseley GL. A pain neuromatrix approach to patients with chronic pain. Manual Therapy 2003;8:130-140
4. Smart KM, Blake C, Staines A, et al. The Discriminative Validity of “Nociceptive” “Peripheral Neuropathic” and “Central Sensitization” as Mechanism-Based Classifications of Musculoskeletal Pain. The Clinical Journal of Pain. 2011:27; 655-663
5. Nijs J, Houdenhove B. Recognition of central sensitization in patients with musculoskeletal pain: application of pain neurophysiology in manual therapy practice. Manual Therapy 2010; 15: 135-141
6. Foster NE, Delitto A. Embedding psychosocial perspectives within clinical management of low back pain: integration of psychosocially informed management principles into physical therapy practice-challenges and opportunities. Physical Therapy 2011; 91: 790-804
7. Sullivan M, Tanzar M, Reardon G, et al. The role of presurgical expectancies in predicting pain and function one year following total knee arthroplasty. Pain 2011
8. George SZ, Wittmer VT, et al. Comparison of graded exercise and graded exposure clinical outcomes for patients with chronic low back pain. J Orthop Sports Phys Ther 2010; 40: 694-704