Pain: More than Just Tissue Damage

Dec 4 2017

Matthew Choman

Pain has long been defined as an unpleasant sensory and emotional experience associated with actual or potential tissue damage.  Everyone has experienced pain at some point, but it is often a difficult concept to define.  It can also be difficult to effectively treat.  Knowing that almost every orthopaedic patient presents with pain, one of the primary jobs of a physical therapist is to decrease pain.  In the last few years, an abundance of pain science research has been published.  With this new research, a number of interesting studies can improve our understanding and perception of pain, as well as how to effectively communicate with our patients.

First, let’s investigate how tissue damage is related to pain and functional outcomes. Sham surgery studies separate people with the same tissue pathology into 2 groups: one group receives the typical surgical intervention, repairing the damaged tissue; the other receives all the same pre-care, aftercare, anesthesia, and incisions, but the tissue damage is not repaired. Then, researchers look at outcomes at various time points in the postoperative recovery period.

The procedures investigated were arthroscopic debridement for osteoarthritis, tendon debridement for tennis elbow, and two for back pain (lumbar vertebroplasty and intradiscal annuloplasty). As one can easily see in the above table, many patients who undergo surgery end up with similar outcomes – and reported pain – as their counterparts who received sham surgery.  This evidence shows that there is more to pain and functional outcomes than just the affected tissues.  Additional research shows that psychological and sociological factors play a role in the perception of pain.

Another example of how pain perception can vary is whiplash. Whiplash is an injury involving violent head motions that can typically happen during motor vehicle accidents (MVA). Unfortunately, these cases are often associated with lawsuits. There are two interesting facts about whiplash that show how complex the pain experience is.  A study looked at how socially different countries have different whiplash statistics. Singapore and Australia have similar MVA rates. However, Australia has a significantly higher rate of whiplash.  Additionally, Australia has a culture of financial gain from MVA, whereas in Singapore, this cultural phenomenon is absent.  In other words, the cultural expectation of potential financial gain contributes to an increase in pain and disability.

 

 

 

 

 

 

(Simotas AC, Shen T)

Conversely, it is interesting to study demolition derby drivers. They sustain high impact collisions at a rate higher than the general population, but experience a disproportionately low rate of whiplash. As seen in the figure, very few drivers experienced pain after 3 weeks!  Anyone who works with patients after MVA knows this is extremely uncommon. These drivers expect these collisions, and they are a source of income.  Also, they do not view them as damaging or dangerous, and thus do not feel prolonged symptoms.  These two points depict how cultural and social conceptions can influence the pain experience.

Another study shows how we talk to patients can have a huge effect. There was a neat study done that looked at how different explanations about ultrasound would affect a patient's pain and range of motion (ROM).  There were 3 ultrasound groups: CG (control group), EG (experimental group), EEG (extra-experimental group). Each was given a different explanation.

CG:  Accurate ultrasound explanation/rationale

EG: “Typically we move the US head in a figure-8 fashion, but some new research has indicated if we perform it clockwise, it helps reduce pain even more.”

EEG: “This improved effect helps unwind the tightness felt and eases back and leg pain a lot. The clockwise ultrasound usually will allow you to bend further forward when we test you after treatment and also you will be able to raise your leg up higher."
 

  (Louw, A, et al.)

The results show that the group that was given a more optimistic – and completely untrue – explanation had a greater improvement in ROM, despite the same exact treatment!  These results led themselves to proving that there is an effect that pain science education can have on patient outcomes.  

Many times, pain is an output from the brain, and not necessarily the involved tissues. Studies now consistently show that teaching patients about the nature of pain improves function.  Explaining that pain does not equal damage is empowering, taking away fear that can hamper patient progress, robbing them from an enjoyable life.  Fortunately, Excel prides itself in having physical therapists that stay current with the most up-to-date literature and evidence-based treatments – including the advances being made in pain science.


References
Melzack, R, Torgerson, WS, On the Language of Pain.  Anaesthesiology. 1971;35:50

Louw A, Diener I, Fernández-de-las-peñas C, Puentedura EJ. Sham Surgery in Orthopedics: A Systematic Review of the Literature. Pain Med. 2016;

Ferrari R, Russell AS, Richter M. [Epidemiology of whiplash injuries: an international dilemma]. Orthopade. 2001;30(8):551-8.

Simotas AC, Shen T. Neck pain in demolition derby drivers. Arch Phys Med Rehabil. 2005;86(4):693-6.

Louw, A., Zimney K., Landers, M.R., Luttrell, M., Clair, B. & Mills, J., 2016, ‘A randomised controlled trial of ‘clockwise’ ultrasound for low back pain’, South African Journal of Physiotherapy 72(1), a306.