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Pain Classifications pt. 1

By Elliott Perkins, DC


This is a multi-part series where I aim to break down different classifications or pain presentations. These classifications differ physiologically as well as the way the patient presents in clinic, and they can act as a framework for how to manage the patient when they see you in a clinic or gym setting. These articles are written with a clinician in mind, but the information can certainly be utilized for anyone working with a pain population, be it a personal trainer or Strength & Conditioning coach. So, a friendly reminder to stay inside your scope of practice and refer to an appropriate professional when required. Pain management can and should always be a multidisciplinary approach!


Another note, these classifications are not diagnoses, nor are they hard and fast rules that must be followed. Always treat your patients as individuals, considering their expectations, beliefs and personal goals, and work accordingly as a team.

I highly recommend reading Dr. Mike Edgar’s post on chronic pain that can be found here, as it will give a background to pain theories. Once you have done that, come on back here!


The most important thing to understand moving forward is the nature of pain. The new definition of pain from the IASP (International Association for the Study of Pain) is “An aversive sensory and emotional experience typically caused by, or resembling that caused by, actual or potential tissue injury”. What this means is that pain is a perception, and is meant to protect us from harm, or from things that resemble harm.

Pain is all about PROTECTION.


An interesting study shows the implications of this. (Hollman, et al., 2018) a group of participants with frozen shoulder had their shoulder range of motion measured before and after undergoing general anaesthetic. While these patients were unconscious their shoulder ROM increased up to 110 degrees in abduction, and no injuries were sustained in the maneuver. This suggests that their restriction is not to do with a capsular contracture but guarding. Pain, stiffness and tightness are all centrally mediated, meaning controlled by your central nervous system and brain. The pain response exists to protect the body from a perceived threat of damage, rather than actual damage. Educating a patient on the nature of pain and how pain does not equal tissue damage is essential for reducing fear and improving the patient’s self-efficacy.

As mentioned in Mike’s article, Professor Lorimer Moseley has a great way of explaining pain. Simply put, he says pain is “when our credible evidence of danger in me is greater than our credible evidence of safety in me”.


An increase in danger = an increase in pain (this can be nociception, thoughts, beliefs and behaviours)


A decrease in danger = a decrease in pain


Note that ANYTHING can increase or decrease pain, it is unique to the person.

For example, Moseley et al. in 2007 performed a study where participants were exposed to an unpleasant stimulus and were asked to rate the intensity of the pain. In one group, there was a red light shining at the participant, in the other group there was a blue light. Despite there being no difference in the temperature between the groups, the red-light group consistently rated the pain to be more intense. Even something as simple as colour can influence pain perception!


(sidenote, we clearly did not have this study in mind when designing our website to be almost entirely red)


It is not only the nature of a stimulus, but also the context within which it is experienced (together with associated memories, emotions and beliefs) that determine whether or not a person will perceive a particular stimulus as painful.


This brings us to the Biopsychosocial model of pain. Pain is not simply something that hurts, it is a combination of multiple entities:


Biological entities: nociceptive signals from real or potential tissue damage


Psychological entities: stress, poor coping mechanisms, catastrophizing/ruminating


Behavioural entities: Memories for example can have an impact on future pain


Sociological entities: Social life, socioeconomic status, access to care

How do we apply the Biopsychosocial model in practice? That is what we will discuss in the coming articles. As an outline, we can follow the following 7 steps:

Step 1: build a therapeutic alliance

Step 2: Identify the patient’s needs and address threats one at a time

Step 3: do not limit your treatment to pain alone, but also to function and behavior. This will help increase the patient’s self-efficacy and minimize rumination.




Step 4: Listen to and value their understanding and narratives about their pain and educate them appropriately but not dismissively. Help them draw their own conclusion through motivational interviewing (more on this later).

Step 5: Understand how their past experiences and current environment shape their pain perception

(anxiety, pain behaviours)

Step 6: Connect with them! (make the patient feel safe. If they can tell that you genuinely care, they will have better success)

Step 7: thoroughly assess your patient and deliver an individualized active treatment plan, keeping in mind their dominant pain classification.



References:


1. Hollmann, L., et al. “Does Muscle Guarding Play a Role in Range of Motion Loss in Patients with Frozen Shoulder?” Musculoskeletal Science and Practice, vol. 37, Oct. 2018, pp. 64–68. DOI.org (Crossref), doi:10.1016/j.msksp.2018.07.001.


2. Smart KM, Blake C, Staines A, Thacker M, et al. “Mechanisms-Based Classifications of Musculoskeletal Pain: Part 1 of 3: Symptoms and Signs of Central Sensitisation in Patients With Low Back (± Leg) Pain.” Manual Therapy, Aug. 2012, doi:10.1016/j.math.2012.03.013.


3. ---. “Mechanisms-Based Classifications of Musculoskeletal Pain: Part 2 of 3: Symptoms and Signs of Peripheral Neuropathic Pain in Patients With Low Back (± Leg) Pain.” Manual Therapy, Aug. 2012, doi:10.1016/j.math.2012.03.003.


4. ---. “Mechanisms-Based Classifications of Musculoskeletal Pain: Part 3 of 3: Symptoms and Signs of Nociceptive Pain in Patients With Low Back (± Leg) Pain.” Manual Therapy, Aug. 2012, doi:10.1016/j.math.2012.03.002.


5. Smart KM, Blake C, Staines A, and Doody C. “The Discriminative Validity of ‘Nociceptive,’ ‘Peripheral Neuropathic,’ and ‘Central Sensitization’ as Mechanisms-Based Classifications of Musculoskeletal Pain.” The Clinical Journal of Pain, Oct. 2011, doi:10.1097/AJP.0b013e318215f16a.


6. Kolski, Melissa C., and Annie O’Connor. A World of Hurt: A Guide to Classifying Pain. Thomas Land Publishers Incorporated, 2015.


7. Lin I, Wiles L, Waller R, et al . What does best practice care for musculoskeletal pain look like? Eleven consistent recommendations from high-quality clinical practice guidelines: systematic review.British Journal of Sports Medicine 2020;54:79-86.


8. McKenzie, Robin, and Stephen May. The Lumbar Spine, Volume One: Mechanical Diagnosis and Therapy. Spinal Publications, 2003.


9. Moseley, Lorimer G., and Arnoud Arntz. “The Context of a Noxious Stimulus Affects the Pain It Evokes:” Pain, vol. 133, no. 1, Dec. 2007, pp. 64–71. DOI.org (Crossref), doi:10.1016/j.pain.2007.03.002.


10. Walton, David M., and James M. Elliott. “A New Clinical Model for Facilitating the Development of Pattern Recognition Skills in Clinical Pain Assessment.” Musculoskeletal Science & Practice, vol. 36, Aug. 2018, pp. 17–24. www.mskscienceandpractice.com, doi:10.1016/j.msksp.2018.03.006.