Back to basics about psychosocial factors and pain – v

I’ve been writing about psychosocial factors and pain but I realise that I haven’t actually defined what I mean by psychosocial factors. The strange thing about this term is that it’s often conflated with “psychological” or “psychopathological” when it’s actually not. So… where to begin?

The Collins English Dictionary defines psychosocial as: “of or relating to processes or factors that are both social and psychological in origin”, while the Oxford English Dictionary defines it as “Of or relating to the interrelation of social factors and individual thought and behaviour.” According to the Oxford, it first appeared in the American Journal of Psychology in 1890 when it was used to describe the factors associated with the increase of alcoholism. An 1899 journal used it to describe “… psycho-social phenomena, such as language, customs, rights, religion etc., arising from the action of social elements with or upon the individual mind.”

So, the term is fairly recent but seems to have always been associated with broader influences on thoughts and behaviour – that is, a reciprocal response between what individuals think and do, and what helps to shape (and also responds to) what happens in the community.

When we think about pain, the most common “psychosocial” factors seem to be psychological – things like attention (vigilance), catastrophising (thinking the worst), negative affect (low mood), treatment seeking (behaviours associated with looking for help), avoidance (not doing, not approaching). What is lacking in clinical practice, in my humble opinion, is the relationship between how these factors develop and are maintained, and how those around an individual (both family and the wider community) respond to these factors. It’s not that there is no research into these relationships – it’s that research is complex, it’s tough to conduct experiments in this field, and effecting change once relationships are identified is pretty hard. More than that, health professionals typically see individuals, not people-in-context.

BUT here are some of the areas currently being explored.

Clinician behaviour – there would be few readers of this blog who are unfamiliar with Ben Darlow’s work on the power of what clinicians say (Darlow, Dowell, Baxter, Mathieson, Perry & Dean, 2013), though he’s not the first research to begin to look at this – Tamar Pincus and others have also reviewed the influence of practitioners beliefs on what they do for people with persistent pain (Parsons, Harding, Breen, Foster, Pincus, Vogel & Underwood, 2007).  The broad conclusions from this body of work, of which these two are tiny tips of a very large iceberg, is that what clinicians believe about pain and chronicity and hurt/harm influences both their treatment recommendations and their attitude towards people experiencing persistent pain, and has a direct effect on chronicity in the acute stages of a pain problem.

Family responses – Herta Flor and colleagues explored the impact of persistent pain on family relationships way back in the 1980’s, while much more recently,  Burns, Post, Smith, Porter et al (in press) investigated the interaction between spouse criticism and the effect on pain intensity and behaviour in people with persistent low back pain. Chan, Connelly & Wallace (2017) established that poor peer relationships influenced both emotional functioning and persistent pain amongst adolescents, while treatment seeking amongst adolescents was found to be associated with elevated treatment seeking in their parents (Stone & Wilson, 2016). Whether the relationships are genetic (in family patterns of persistent pain and disability), or learned (social learning theory) or a mix of both – it looks like how others respond and behave in relation to pain and disability has a strong influence on persistent pain in an individual.

Work – This, naturally, has been the place of many a study trying to establish a relationship between biomechanical factors and the onset and maintenance of pain, but it has also been the location for studies examining social relationships like supervisory responses, peer relationships, employer flexibility along with the personal effects of workplace stress on the body. I’m not going to review the myriad studies, but point you to a good systematic review of prognostic factors for return to work by Steenstra, Munhall, Irvin, Oranye, Passmore et al (2016) to demonstrate just how many factors have already been identified.

I’ve barely touched the surface of the social aspects influencing our experience of pain and disability. It’s evident that these factors have been identified – but let me ask you this: How often do you identify and then provide an intervention for these social factors? And if not, why not? And if not you – who?


Burns, J. W., Post, K. M., Smith, D. A., Porter, L. S., Buvanendran, A., Fras, A. M., & Keefe, F. J. (2017). Spouse criticism and hostility during marital interaction: effects on pain intensity and behaviors among individuals with chronic low back pain. Pain.
Chan, S. F., Connelly, M., & Wallace, D. P. (2017). The Relationship Between Pain Characteristics, Peer Difficulties, and Emotional Functioning Among Adolescents Seeking Treatment for Chronic Pain: A Test of Mediational Models. Journal of Pediatric Psychology, jsx074.
Darlow, B., Dowell, A., Baxter, G. D., Mathieson, F., Perry, M., & Dean, S. (2013). The enduring impact of what clinicians say to people with low back pain. The Annals of Family Medicine, 11(6), 527-534.
Flor, H., Turk, D. C., & Scholz, O. B. (1987). Impact of chronic pain on the spouse: marital, emotional and physical consequences. Journal of psychosomatic research, 31(1), 63-71.
Parsons, S., Harding, G., Breen, A., Foster, N., Pincus, T., Vogel, S., & Underwood, M. (2007). The influence of patients’ and primary care practitioners’ beliefs and expectations about chronic musculoskeletal pain on the process of care: a systematic review of qualitative studies. The Clinical journal of pain, 23(1), 91-98.
Steenstra, I. A., Munhall, C., Irvin, E., Oranye, N., Passmore, S., Van Eerd, D., … & Hogg-Johnson, S. (2016). Systematic review of prognostic factors for return to work in workers with sub acute and chronic low back pain. Journal of occupational rehabilitation, 1-13.
Stone, A. L., & Wilson, A. C. (2016). Transmission of risk from parents with chronic pain to offspring: An integrative conceptual model. Pain, 157(12), 2628-2639.

Back to basics about psychosocial factors and pain – iii

Last week I discussed some of the areas in the brain, and basic principles, that are currently thought to influence our pain experience. This week I thought I’d introduce one of my favourite ways of considering pain mechanisms, mainly because it helps me think through the four main kinds of mechanisms, and can influence our treatment approach. At this stage I want to raise my hand to acknowledge the following:

  • My gratitude to Dr John Alchin, longtime friend and colleague, who first pointed this paper out to me and has shared it with hundreds of people who go to see him at the local tertiary pain management centre.
  • We know this is a simplified, under-developed approach to mechanisms underpinning pain, but it’s helpful nevertheless.
  • Most of our patients will have a combination of mechanisms involved in their experience, not just one.
  • This approach to mechanisms doesn’t include the psychological or social – just the primary biological processes.
  • Throughout this blog, when I use the word “pain” I mean the experience we have once whatever mechanisms involved filter up through to our awareness. So while I talk about peripheral mechanisms, they’re only experienced as pain once we become aware of them – and that process involves a whole lot of what I discussed in my last post .

Clifford Woolf wrote this paper in 2010, and although the research into mechanisms has continued unabated, I think it provides clinicians with a reasonable guide to considering how best to tackle treatment. He begins by dividing the mechanisms into “useful” and “useless” pain – ie pain that is useful for adaptation, survival, warning, alerts. Just as it’s possible to have dysfunction or disease of our cardiac, pulmonary, gastro-intestinal, and skeletal systems, I think it’s just as plausible that we can have something go wrong with our nociceptive system. In fact, because of its complexity, it seems probable to me at least that there are many different ways this system can fail to work properly. But more about that shortly! Let’s begin with the useful pain.

Nociceptive pain – is considered to be pain that is, as Woolf puts it, our “early-warning physiological protective system”. When we touch something super cold, super hot, or a chemical that can harm us (think chilli pepper!), or meet a mechanical force that activates mechano receptors, our high threshold nociceptors are activated – well in advance of tissue damage, I quickly add. This process activates withdrawal – even in simple single-celled animals – and saves us from harm. When combined with behavioural responses including vocalisation, grimaces and other pain behaviours, we signal to everyone around us that we’re in danger, and others shouldn’t do what we’ve just done (Melzack, Dennis, Kosterlitz & Terenius, 1980).  For me, the cool thing about nociceptive pain is that once you’ve removed that stimulus (got rid of the chilli on your lips, let go of the ice-cube or the hot mug of coffee, or shifted in your seat to relieve your butt) the pain simply goes away. Just like that. How cool?!

Inflammatory pain – is also a useful pain to have. Unlike nociceptive pain, inflammation involves disruption to the tissues, triggering a release of a whole bunch of neurochemicals and cells that quickly lower the point at which nociceptors will fire (making you much more sensitive to mechanical, chemical and temperature input), and increasing the blood supply to allow foreign material, dead cells and spent neurochemicals to be whisked away. Inflammation is reasonably easy to see in the periphery (though not so easy in the internal organs because the innervation is more diffuse) and you’ll all have had it – think sunburn (I know you’re not meant to, but everyone gets sunburned at least once, especially in our NZ sun). With sunburn you’re red, hot and often swollen, and you really know it when you step into the shower! That experience of ouch! to your usual shower temperature (and the ouch! when you towel down) is allodynia, or the experience of pain when a usually comfortable stimulus is applied. You’ll experience hyperalgesia if your mate comes along and slaps you on your sunburned shoulders!

Now both of these mechanisms are useful because they alert us to threat, they make it more difficult to move around, and we often respond to them with changes in our behaviour that act as a signal to others around us. Let’s turn the attention to two mechanisms where there is something gone awry with the nervous system – in other words, useless pain.

Neuropathic pain – is defined by IASP as “pain caused by a lesion or disease of the somatosensory nervous system.” What this means is that there must be an identifiable lesion in the nervous system somewhere – something that can be imaged or tested to demonstrate damage. This could be in the periphery – think of radial nerve entrapment with its characteristic tingling, deep aching and burning over the distribution of the nerve. It could be in the spinal cord itself – think of a complete spinal cord injury where the person is unable to move from the lesion down, and who also gets the same tingling, aching, burning and electric shock pain over the same area. A simple example would be radicular pain where the nerve root is compressed – and this can be seen on imaging, and where the pain is experienced over the same nerve distribution. The final group in this nasty set of neuropathies is when someone has a stroke, where part of the brain is damaged leading to intractable, deep, aching pain with electric shock-like pain just to make it nastier. For a great paper reviewing neuropathic pain, Finnerup and colleagues wrote one published in 2016 (see below), describing a grading system to indicate possible, probable and confirmed neuropathic pain. The hallmark of this pain is that it doesn’t represent tissue damage except in the area of the nervous system where the lesion is located. In other words, that pain down the leg is not where the problem lies in radicular pain – it’s near the spinal cord. So this pain doesn’t have a function for survival – it’s just a horrid nuisance.

The final mechanism is poorly understood – even less well understood than neuropathic pain. This is where ostensibly the nervous system appears intact. The pain experience might be in multiple parts of the body, it could be just in the head (migraine, for example), or it could be just in the shoulder (frozen shoulder maybe?), or it might be everywhere (fibromyalgia). The name isn’t even completely determined – it’s called “dysfunctional” by Woolf, and he collapsed this and neuropathic pain into one mechanism, but I prefer to keep it separate because it’s more helpful for management especially when a neuropathy might be amenable to surgery. Another term, and one I like, is nociplastic – referring to the idea that it’s the unhelpful neuroplasticity of our nervous system that has over-responded to potential threat (Kosek, Cohen, Baron et al, 2016). Some would argue that this mechanism is partly a general tendency to a lower nociceptive threshold, maybe genetic, maybe behavioural (ie we’ve learned to monitor and respond to threat perhaps because of early life experiences), perhaps a diathesis-stress where the predisposition exists but it’s not brought into expression until a stressor, perhaps a virus or an injury, exerts an influence on homeostasis.

Ultimately, pain is an experience that we’ve all had, and one that has individual meaning for each of us based on our previous experiences, predictions for the future, current goals, culture and biology. What a mechanisms-based approach to pain management might mean is better and more accurate management for each one. So we’d be looking to remove that bunion so people can walk more easily; reduce the inflammation in an auto-immune disease; decompress a squished nerve in neuropathic pain and look to altering plasticity in nociplastic pain. But pain is weird and as I said at the very beginning, it’s entirely possible to have more than one mechanism involved – and because pain is not just biology, we’d be foolhardy to think that just by down-tuning the intensity, everyone so treated will go “back to normal”. More on that next week!



Finnerup NB, Haroutounian S, Kamerman P, et al. Neuropathic pain: an updated grading system for research and clinical practice. Pain. 2016;157(8):1599-1606. doi:10.1097/j.pain.0000000000000492.
Kosek, E., Cohen, M., Baron, R., Gebhart, G. F., Mico, J. A., Rice, A. S., … & Sluka, A. K. (2016). Do we need a third mechanistic descriptor for chronic pain states?. Pain, 157(7), 1382-1386.

Melzack, R., Dennis, S. G., Kosterlitz, H. W., & Terenius, L. Y. (1980). Phylogenetic evolution of pain-expression in animals. Pain and Society, 13-26.

Woolf CJ. What is this thing called pain? The Journal of Clinical Investigation. 2010;120(11):3742-3744. doi:10.1172/JCI45178.

Conversations about cannabis for chronic pain

The debate about cannabis and derivatives for persistent pain continues to grow in New Zealand, and elsewhere in the world. Many people I’ve treated and who are living with persistent pain say they like to use cannabis (in a variety of forms) to help with pain intensity and sleep, adding their voices to those wanting “medicinal” cannabis to be approved. In the few patients I’ve worked with who have managed to obtain a cannabis product (in NZ it has to be legally prescribed and will generally be in the form of Sativex or similar) the effect doesn’t seem as profound as the real thing (whether smoked, vaped, or in edibles).

Here’s my current position, for what it’s worth. Right now I think cannabis legislation needs an overhaul. Cannabis doesn’t seem to fit into the same class as synthetic drugs (often called “herbal highs” or synthetic “cannabis”) – for one, the plant probably contains a whole lot of substances that have yet to be fully analysed, and for another, I have yet to see a death reported from cannabis use, yet in Auckland, NZ, alone this year there have been around 9 people who have died from taking the synthetic substance, whatever it is. Cannabis seems to cause less harm than legal substances like alcohol and tobacco, and in many places in the world it’s been legalised with some interesting effects on use of opioids.

Ever since Professor David Nutt visited New Zealand a few years back, I’ve been convinced it’s time for a rethink on cannabis laws, but at the same time I’m not ready to support wholesale legalisation of “medical” marijuana. Here are a few reasons why:

  • When a doctor prescribes a drug, he or she is able to rely on the manufacturer making a consistent product, with a consistent amount of “active” ingredients, and a consistent quality. At present, with the exception of the two versions available in New Zealand, this can’t be guaranteed. Plants vary in the combination of active chemicals in them, and storage and age of the product influence the availability of those chemicals when inhaled or ingested. Just as we don’t suggest people go and grow their own opium poppies because we know that opioids are effective analgesics, I don’t think it’s time to allow people to grow their own cannabis for medicinal purposes, such as treating pain. A doctor can’t know just how much of a dose a person can get because in NZ we don’t yet have a controlled environment for cannabis production.
  • When a doctor prescribes a drug, he or she is also guided by the indications for use. So, although some medical practitioners prescribe “off-label” use for medications (a good example is nortriptyline, an antidepressant used often for pain reduction), generally there are good double-blinded, randomised controlled trials to determine whether the active drug is more effective than placebo. When we read about cannabis use for medicinal reasons we hear of its use for cancer (mainly nausea, but also pain), neuropathic pain, and in the general media we hear of its use for migraine, period pain, abdominal pain, fibromyalgia, osteoarthritis – there’s very few pain disorders that cannabis isn’t seen to be appropriate. But the truth is, we don’t really know which kind of pain (the underlying mechanism) will respond, and what pains don’t respond. It’s still a bit of a mystery – mind you, this is not any different from other medications for pain for which N=1 seems to be the mantra.

Why might I support a change to marijuana laws?

Well, an interesting study from the Northeastern United States, and published in the journal Pain, looked at the perspectives of people enrolled in legal medical marijuana clinics. It was quite a large study of 984 people, so should represent a good cross-section of those using the drug within a legal system. Participants were asked to complete an online survey, and their responses were analysed by a psychologist who was “not a cannabinoid expert”, arranging the data into themes and subthemes. (As an aside, apparently this was carried out using a “Grounded Theory perspective” based on Corbin and Strauss – BUT essentially the researchers didn’t follow grounded theory methodology throughout, and instead it should be called a thematic analysis using inductive coding. Pedant, yes!). The data was then examined to quantify the responses (another violation of GT methodology), and re-examined by another co-author for verification.

What they found was a group of people, over half women, with 2/3 indicating they’d been diagnosed with chronic pain by a medical professional. Diagnoses varied, but most (91%) had low back and neck pain, 30% with neuropathic pain, 23% with postsurgical pain, nearly 22% with abdominal pain, 20% with chronic pain after trauma/injury, 7% with cancer pain and 5% with menstrual pain.  Most people smoked cannabis either by joint, pipe or bong; some used a vaporiser, some had edibles or a tincture, and least, some sort of ointment.

The participants indicated it was on average 75% effective at reducing/treating symptoms, which is extraordinary when you realise that traditional forms of medication for neuropathic pain may reduce pain by 50% in around 1  in 4 people (Woolf, 2010). Participants spent around $3118 each year, but this was skewed because concentrates cost $3910, while topicals were $814. Joints were more expensive than vaporised product ($260 different!).

Analysing the positives of cannabis, participants reported pain relief, or at least being able to tolerate the pain more easily; while sleep benefits was the next most significant theme. Participants were encouraged that cannabis doesn’t have overdose potential, it’s natural, there are a wide range of strains with different characteristics, and limited potential for dependence.

There were numerous other positive aspects to using cannabis this way, according to the participants: things like “feeling normal”, “I am more active and able to do things I want”, being “distracted” from the pain, “able to focus”, and “able to relax”.

Negative perspectives included the cost (too expensive – in NZ Sativex is around $1000 a month – not covered by NZ pharmaceutical subsidies); some people didn’t like the smell, the effects on lungs and breathing, appetite changes (and gaining weight), and some emotional effects like anxiety or paranoia. Stigma and judgement by others also features, as did the difficulty accessing the drug, and conflict about the different laws applying to cannabis use – noting that the US has different federal and state laws.

Overall, the responses from these participants suggest a benign, mainly positive response to a drug, with negatives primarily around the social aspects – stigma from health providers, other people thinking of the participants as stoners, the legal situation and so on. For me, the limitations of this study really preclude any major judgement as to benefit or otherwise. We only know what this group of people believed, they have a vested interest in promoting benefits because negatives won’t support their belief that this is a viable treatment option, we don’t know the effect on function (particularly objective data), and we have no way of verifying the diagnoses individuals reported as the reason for prescription.

My conclusion?

It’s way past time to discuss cannabis use, health risks and health benefits. To have an open discussion about use for medicinal reasons, we need to remove the current barrier: the legal situation. While people have a vested interest in promoting the benefits over risks or adverse effects, we’re not going to have a very clear picture of what happens with ongoing use. I don’t support the use of cannabis as a medicinal product – to me there are far too many unknowns, and I think we risk wedging open a gate that has, until now, been useful for limiting the risk from pharmaceutical harms. We need to subject cannabis to the same level of rigour as any other pharmaceutical product being introduced to the market.

On the other hand, I think removing legal barriers to recreational use is about balancing the benefits and harms of this substance against other substances used for similar reasons. Alcohol and tobacco are well-known for harmful effects. Prohibition of alcohol did not work. Tobacco smoking is reducing over time courtesy of a committed campaign documenting harms, as well as raising the price via taxation. We can’t campaign around health harms for a product that isn’t legal. We can’t establish useful regulation over who produces it, who can buy it, where it can be used, the effects on work injury/vehicle injury, we can’t represent the undoubted benefits, and we look, to many people, to hold a double-standard.

And sneaking cannabis use in under the guise of “medicinal” use just isn’t on, in my humble opinion. Let’s not put medical practitioners in an unenviable situation where they’re asked to prescribe a product that is not yet examined to the level we expect for every other pharmaceutical product on the market. Let’s spend some precious research funding to establish WHO cannabis helps, WHAT it helps with, and HOW it helps – and most importantly, let’s look at whether it helps produce outcomes that surpass other approaches to persistent pain. We need to face it, currently our treatments are not very good.


Piper, B. J., Beals, M. L., Abess, A. T., Nichols, S. D., Martin, M. W., Cobb, C. M., & DeKeuster, R. M. (2017). Chronic pain patients’ perspectives of medical cannabis. Pain, 158(7), 1373-1379.

Woolf, C: (2010). Review: Overcoming obstacles to developing new analgesics, Nature Medicine (Supplement); 16,11: 1241 – 47

Great expectations – and low back pain

Have you ever wondered why there are so many treatments for low back pain? Like there are actually hundreds of different ways to “treat” back pain… yet the truth is, none of them work for everyone. Actually, most of them seem to help pass the time until low back pain settles of its own accord. Until it’s back again (no pun intended!).

This post is prompted after reading a string of general news articles discussing the common non-specific low back pain – under various guises of “dead butt syndrome“, “Dr Tom: Ouch I’ve hurt my back” and the like – I think it’s time for a frank discussion about the natural history of low back pain, as found in large epidemiological studies. There’s no doubt that low back pain is a problem around the world, and I think it’s partly due to unmet expectations (along with a whole lot of other variables). The Global Burden of Disease found low back pain to be the most common reason for days lived with disability around the world – that’s more than anaemia, depression, hearing loss, migraine!

Low back pain is common in every single country in the world.

Dunn, Hestbaek & Cassidy (2013) examined the prevalence of low back pain across the life span – they found that many of us view low back pain as a simple “yes/no” question – do you have it, or don’t you. They point out that people with no back pain at the time of a survey are not all the same: some might never have had a bout ever, while some might have had several bouts but just don’t have one right now. These presentations are not the same! Those who have had a previous episode will have developed an understanding of back pain on the basis of what happened, and this will influence their expectations, and subsequent response, to treatments.

Dunn, Hestbaek & Cassidy found that children/adolescents have a point prevalence (ie at the time of the survey, they reported they had back pain) of 12%. As people get older the prevalence continues to be around 12%. The elderly, those over 60 (that doesn’t really feel old to me!), seem to have a prevalence similar to people in middle age, and activities affected by low back pain seem to increase as we age.

Given the lifetime prevalence of low back pain is around 80% (or more), following people up over time seems to paint a different picture from the point prevalence studies: it’s not the same 12% of people that has low back pain all the time. Some studies show that at least 40% of people do recover within a year of an episode (see Hestbaek, Leboeuf-Yde, & Manniche, 2003). A Danish study with 5 year follow-up found around 23% of people consistently reported no pain days during the previous year (during the study) but around 10% reported more than 30 days of back pain every time they were asked. So, while long-term low back pain isn’t common in the adult population, most people do have a couple of bouts over long periods of time.

What are the risk factors? Well one clear risk factor is having had a previous episode, although this isn’t a consistent predictor for long-term back pain. Perhaps we should take a look more closely at the natural course of acute neck and low back pain – from the Norwegian longitudinal studies. From one city in Norway, these researchers screened 9056 people between 20 – 67 years old to identify those with a brand new bout of neck or back pain in the previous month – 219 people were identified, then followed for 12 months. What these researchers found was pain decreasing rapidly in the first month, irrespective of treatment, thereafter though, back pain didn’t change for the rest of the year especially for those with pain in the neck as well as the back at the first assessment, and for those who had 4 or more pain sites in the beginning.

Now what’s really interesting about this study is that the pain reduction people experienced, particularly in low back pain, was pretty close to the pain reduction people achieved whether they had treatment, or not. Hmmmm. Next question: what if we look at all the treatments people get, and those who are in the control group, and pooled that information to find out what happens? Artus, van der Windt, Jordan & Croft examined whether just taking part in a study on low back pain might influence outcomes – so they pooled 70 RCTs and 19 cohort studies, and both sets of data showed “a rapid improvement in the first six weeks followed by a smaller further improvement until 52 weeks. there was no statistically significant different in pooled standardised mean change (a measure used to compared the pooled within-group change in pain in RCTs with cohort studies) – get this, at any time point.

But wait, there’s more!

Axen & Leboeuf-Yde (2013) looked at the trajectories of low back pain over time. They summarised four studies in primary care or the general population, finding that over the course of between 12 weeks and 12 months, participants could be divided into two to four groups: one group remained uncomfortable, perhaps staying that way over the whole 12 months (around 10 – 21%); one group also remained uncomfortable but they reported their pain as “moderate” or “mild” – around 36%; another approximately 30% experienced fluctuating or intermittent low back pain; and finally, the group we love – those who recovered and remained that way, around 30 – 58%.

This is not the picture we hear in the media. This is not what we were taught. And yes, I know there are problems with pooled data because individualised responses get ironed out. But what all this says to me is – our patients come to us expecting that low back pain should completely resolve. The reality is that for a lot of people, back pain will come and go throughout the lifetime.

What does this mean to me?

Isn’t it time to give people an idea that if they have a bout of back pain, chances are high they’ll have another. Complete resolution of low back pain may not occur for a large number of people. A new bout of low back pain may not mean a new “injury” (given we don’t know why many people develop back pain in the first place). Learning to self-manage a bout of back pain is likely to save people a load of heartache, not to mention a lot of money. And maybe it’s the latter that means it’s very hard to find clear, effective messages about just how safe a painful back is. It’s far easier to sell a message of vulnerability, of the need for treatment for that “unhappy spine” as a chiropractor in Christchurch calls it. And of course, if we continue to allow the expectation that all pain should be gone, we’re going to be in business for a very long time…


Artus, M., van der Windt, D., Jordan, K.P., & Croft, P.R. (2014). The clinical course of low back pain: A meta-analysis comparing outcomes in randomised clinical trials (rcts) and observational studies. BMC Musculoskeletal Disorders, 15, 68.

Axén, I., & Leboeuf-Yde, C. (2013). Trajectories of low back pain. Best Practice & Research Clinical Rheumatology, 27(5), 601-612. doi:

Dunn, K.M., Hestbaek, L., & Cassidy, J.D. (2013). Low back pain across the life course. Best Practice & Research in Clinical Rheumatology, 27(5), 591-600.

Hestbaek L, Leboeuf-Yde C, Engberg M, Lauritzen T, Bruun NH, Manniche C. (2003). The course of low back pain in a general population. Results from a 5-year prospective study. Journal of Manipulative & Physiological Therapeutics, 26(4):213–9.

Hestbaek L, Leboeuf-Yde C, Manniche C. (2003). Low back pain: what is the long-term course? A review of studies of general patient populations. European Spine Journal, 12(2):149–65.

Vasseljen, O., Woodhouse, A., Bjorngaard, J.H., & Leivseth, L. (2013). Natural course of acute neck and low back pain in the general population: The HUNT study. Pain, 154(8), 1237-1244.

Primary pain disorders

In a move likely to create some havoc in compensation systems around the world (well, at least in my corner of the world!), the International Association for the Study of Pain has worked with the World Health Organisation to develop a way to classify and thus record persistent pain conditions in the new (draft) ICD-11. While primary headache disorder has been in the classification for some years, other forms of persistent pain have not. Recording the presence of a pain disorder is incredibly important step forward for recognising and (fingers crossed) funding research and treatment into the problem of persistent pain. As the IASP website states:

Chronic pain affects an estimated 20 percent of people worldwide and accounts for nearly one-fifth of physician visits. One way to ensure that chronic pain receives greater attention as a global health priority is to improve the International Classification of Diseases (ICD) diagnostic classification.

The classifications are reasonably straightforward, with an overall classification of “chronic pain”, and seven subcategories into which each type of pain can be placed.

Now there will be those who are uncomfortable with labelling a symptom (an experience, aporia, quale) as a separate diagnosis. I can understand this because pain is an experience – but at the same time, just as depression, which is an experience with clinical and subclinical features, so too is pain. There is short-term and useful pain, serving as an alert and warning, and typically an indication of the potential or actual threat to bodily integrity. Just as in depression which has short-term and usually useful episodes of sadness, withdrawal and tearfulness (as in grief). At the same time, there are periods when sadness becomes intractable and unhelpful – and we call this depression. Underlying both of these situations are biological processes, as well as psychological and social contributors. Until now, however, persistent pain has remained invisible.

The definition of chronic pain, at this time, is the IASP one from the 1980’s:

“Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage. Often, pain serves as a symptom warning of a medical condition or injury. In these cases, treatment of the underlying medical condition is crucial and may resolve the pain. However, pain may persist despite successful management of the condition that initially caused it, or because the underlying medical condition cannot be treated successfully.

Chronic pain is pain that persists or recurs for longer than three months. Such pain often becomes the sole or predominant clinical problem in some patients. As such it may warrant specific diagnostic evaluation, therapy and rehabilitation. Chronic pain is a frequent condition, affecting an estimated 20% of people worldwide. This code should be used if a pain condition persists or recurs for longer than 3 months.”

Chronic Primary Pain is defined as “…chronic pain in one or more anatomical regions that is characterized by significant emotional distress (anxiety, anger/frustration or depressed mood) and functional disability (interference in daily life activities and reduced participation in social roles). Chronic primary pain is multifactorial: biological psychological and social factors contribute to the pain syndrome. The diagnosis is appropriate independently of identified biological or psychological contributors unless another diagnosis would better account for the presenting symptoms. Other chronic pain diagnoses to be considered are chronic cancer pain, chronic postsurgical or posttraumatic pain, chronic neuropathic pain, chronic headache or orofacial pain, chronic visceral pain and chronic musculoskeletal pain. Patients with chronic primary pain often report increased depressed and anxious mood, as well as anger and frustration. In addition, the pain significantly interferes with daily life activities and participation in social roles. Chronic primary pain is a frequent condition, and treatment should be geared towards the reduction of pain-related distress and disability.” (definition are found here)

The definition doesn’t require identified biological or psychological contributors – so people with primary pain would be those who have fibromyalgia, persistent low back pain, perhaps even “frozen” shoulder. The main requirement is that the person is distressed by it, and that it interferes with life. Now here’s a bit of a problem for those of us who have learned to live well with our persistent pain – I experience widespread pain, but generally I’m not distressed by it, and seeing as I’ve lived with it since my early 20’s, I find it hard to work out whether I’m limited by it, or whether I’ve just adjusted my life around it, so it doesn’t really get in the way of what I want to do. Technically, using the draft definition, I might not be given the label. Does this mean I don’t have chronic primary pain?

Why did I suggest compensation systems might be interested in this new classification? Well, in New Zealand, if a person has a pre-existing condition, for example they have osteoarthritic changes in their spine even if it’s not symptomatic (ie it doesn’t hurt), and then lodges a claim for a personal injury caused by accident, they may well find their claim for cover is declined.  What will happen if someone who has fibromyalgia, has an accident (say a shoulder impingement from lifting something heavy overhead), and the problem fails to settle? I think it’s possible they’ll have their claim declined. Low back pain is probably the most common primary pain disorder. Thousands of people in New Zealand develop low back pain each year. Few will have relevant findings on imaging – and even if imaging shows something, the potential for it to be directly related to the onset of low back pain is open to debate. Especially if we consider low back pain to be a condition that doesn’t just appear once, but re-occurs thereafter (1-7). What will this mean for insurers?

I don’t know where this classification will lead insurers, but from my perspective, I can only hope that by incorporating chronic pain into the ICD-11 we will at least begin to show just how pervasive this problem is, and how many people need help because of it. And maybe, just maybe, governments like the New Zealand government, will begin to take persistent pain seriously and make it a national health priority.

  1. Dunn, K.M., Hestbaek, L., & Cassidy, J.D. (2013). Low back pain across the life course. Best Practice & Research in Clinical Rheumatology, 27(5), 591-600.
  2. Artus, M., van der Windt, D., Jordan, K.P., & Croft, P.R. (2014). The clinical course of low back pain: A meta-analysis comparing outcomes in randomised clinical trials (rcts) and observational studies. BMC Musculoskeletal Disorders, 15, 68.
  3. Vasseljen, O., Woodhouse, A., Bjorngaard, J.H., & Leivseth, L. (2013). Natural course of acute neck and low back pain in the general population: The HUNT study. Pain, 154(8), 1237-1244.
  4. Hoy, D., March, L., Brooks, P., Blyth, F., Woolf, A., Bain, C., . . . Buchbinder, R. (2014). The global burden of low back pain: Estimates from the global burden of disease 2010 study. Annals of the Rheumatic Diseases, 73(6), 968-974.
  5. Campbell, P., Foster, N.E., Thomas, E., & Dunn, K.M. (2013). Prognostic indicators of low back pain in primary care: Five-year prospective study. Journal of Pain, 14(8), 873-883.
  6. Axén, I., & Leboeuf-Yde, C. (2013). Trajectories of low back pain. Best Practice & Research Clinical Rheumatology, 27(5), 601-612. doi:
  7. Hoy, D. G., Smith, E., Cross, M., Sanchez-Riera, L., Buchbinder, R., Blyth, F. M., . . . March, L. M. (2014). The global burden of musculoskeletal conditions for 2010: an overview of methods. Annals of the Rheumatic Diseases, 73(6), 982-989. doi:10.1136/annrheumdis-2013-204344

Exercise? Who me? Yoga or physiotherapy or education…

Exercise, while one of The Most Important self management approaches for persistent pain, is not an easy sell to someone who is experiencing pain. Especially not if that exercise looks like huffing and puffing, hauling on bits of metal in a gym, or wearing lycra. Not to mention the “sports drinks”…  Those things aside, exercising is a good thing. You heard it from me, and I have declared my body an exercise free zone! The thing is, what kind of exercise, for what purpose, and how to get introduced to it.

Personally I’m a fan of exercise that achieves something else other than “getting fit”. I like gardening, I love dancing, I enjoy cycling (especially to the store to get a GREAT coffee!). Walking the dog is fun. Swimming (especially snorkeling) is awesome! I like my exercise to do more than bring on the endorphins, especially as I don’t get much of that post-exertional analgesia that many people do – and believe me, they do (Ellinson, Stegner, Schwabacher, Koltyn & Cook, 2016). I like my exercise to look like the things I need or want to do, so that when I need to do ’em, I’m in fit state to get on and do ’em.

So what kind of exercise works best? One sage told me “the exercise the person does!” and there is some truth to that, so when I begin talking to someone about exercise, I’m looking for something they can do regularly, that fits into their lifestyle, that makes them feel good, and has some other benefit to them. That benefit might be the social thing – going to a box-fit class with a group of others all bent on getting their fix of play-fighting. It might be the solitary thing – long walks along the beach with the dog for company. It might be the music – in my case, it’s belly dance (and I dare anyone to do a 5 minute shimmy drill while keeping an isolated upper body, a loose shimmy and smile!).

I like the idea of having variety – who says we need to do the same kind of exercise every day? So it’s a wet day and I don’t fancy taking my bike out in the rain, I can turn to my dance practice, or do the dusting, or vacuum the floors. It’s a frosty day and I can go for a brisk walk and take photographs of gorgeous sparkly frosty droplets while Sheba-the-wonderdog huffs steam and sniffs at the local scents. If it’s a warm day, why not head to the pool for a lap or two? If it’s a busy day and I don’t have time, what about some “exercise snacks”? Five minutes of exercise every 25 minutes adds some pretty quickly, so it’s lunges and chair dips and wall presses and shimmy practice in between writing.

Over time we’re seeing more research looking particularly at yoga for persistent pain of all kinds. Yoga comes in many different forms, and in this case I’m guessing the more extreme forms of hot yoga and contortion is not being studied. Some of the studies are appearing in rather eminent journals, like this one from the Annals of Internal Medicine and authored by a very large team including Saper, Lemaster, Delitto and colleagues (2017).

This study is a “non-inferiority” study, looking to establish whether yoga or physiotherapy, or indeed education, can help people living with chronic low back pain. Now I’m not going to do a blow-by-blow analysis of the study, that’s for you to do. What I am going to do is look at what the yoga consisted of – and see why, perhaps, yoga is getting so much research interest. BTW, yoga was found to be non-inferior to physiotherapy, and both yoga and PT were more likely than education to have a clinically meaningful response, although neither yoga nor PT were superior to education.

This is the basic format of the yoga class: Each class began with relaxation and meditation exercises, yoga breathing, and yoga philosophy. It continued with yoga poses and
concluded with relaxation. Pose variations and aids (such as chair, strap, and blocks) accommodated various abilities. Thirty minutes of daily home practice, facilitated by a DVD, a manual, and take-home yoga supplies, was strongly encouraged.

Yoga appeals to many because it seems to begin where people are at – it’s not huffy-puffy, things don’t jiggle, and generally the classes begin and end with the ritual of breathing and meditation. I like the idea of yoga (and yes, I’ve done a class or two!), because it doesn’t involve a lot of gadgets, you can do it alone or in a group, and it feels good. What I don’t like about yoga is the need to get effective and consistent feedback about how well you’re performing the poses, especially in the beginning, which means it can be difficult to do on your own without a teacher.

For people who find exercising both difficult and painful, yoga is a good place to start. I think attending classes is crucial (or at least having an instructor and a mirror!). Learning to use the meditation and breathing is integral to the exercise – and it’s this that I think makes yoga an effective addition to the exercise toolkit. What I’m less sure of is whether it’s better than any other form of exercise – or, in my case, the many different types of movements that I use in my weekly routine. And there’s the rub. As an occupational therapist, exercise is something people choose to do as a form of occupation (valued and meaningful activity). I also enjoy a bunch of other movement-based occupations, and to me these are as valid as yoga or the PT exercises included in this study. What my approach lacks, however, is a researched basis for it.

But here’s the thing: to date the research supporting exercise for people with persistent pain shows modest effects. And those effects are completely lost if the person doesn’t do the exercise. So why not have a wide range of whole-body movement practices to draw on, allowing the person to pick and choose and get out and do something every day, even if it doesn’t fit with our modern notions of what exercise should be?



Ellingson, L. D., Stegner, A. J., Schwabacher, I. J., Koltyn, K. F., & Cook, D. B. (2016). Exercise Strengthens Central Nervous System Modulation of Pain in Fibromyalgia. Brain Sciences, 6(1), 8.

Saper, R. B., Lemaster, C., Delitto, A., & et al. (2017). Yoga, physical therapy, or education for chronic low back pain: A randomized noninferiority trial. Annals of Internal Medicine. doi:10.7326/M16-2579

Returning to work, good or bad?- a very complex question

One of the main reasons returning to work is a priority in many healthcare systems is simply that compensation and off-work benefits is the most costly portion of the bill for people with ill health. This naturally leads to a strong emphasis in most rehabilitation, especially musculoskeletal rehabilitation in New Zealand, to help people return to work as soon as practicable. At times the process can be brutal. In my own case, after 18 months of working part-time due to post-concussion symptoms after a “mild” traumatic brain injury, I had the hard word put on me to get back to my job or I’d be sent to work back on the wards (after having spent most of my clinical career working in pain management). Not quite the supportive approach I needed when I was having to sleep for at least an hour every afternoon!

I can well remember the pressure of trying to maintain my work output to the satisfaction of my manager, keep my home responsibilities going (I had teenaged children at the time), manage all the paperwork required just to be part of a rehabilitation system, maintain my relationship which was strained just because I had no energy to play or have fun the way I used to. Oh and I had weekly rehabilitation appointments to top it all off! Not easy to keep your cool when everything seems balanced on a knife-edge.

Yet, despite the challenges of going back to work, most accounts of recovery from musculoskeletal pain find that returning to work forms a crucial element in maintaining long-term gains. The study that sparked this post is a good example: Michael Sullivan and colleagues, set in Montreal, Canada, found that returning to work helps to maintain treatment gains in people with whiplash injury. Of the 110 people enrolled in this study, 73 participants returned to work by the end of one year, while the remaining 37 remained off work. Using regression analysis, the researchers found that the relationship  between return to work and maintaining treatment goals remained significant even when confounds such as pain severity, reduced range of movement, depression and thinking the worst (catastrophising) were controlled. What this means is that something about those who returned to work seemed to help them achieve this, and it wasn’t the usual suspects of low mood or that the injury was more severe. What is even more striking is that those who didn’t return to work actually reported worsening symptoms.

There are plenty of arguments against this finding: could it be that those who didn’t return to work just didn’t respond as well to the treatment in the first place? Well – the authors argue no, because they controlled for the things that should have responded to treatment (eg range of movement, mood). Participants in the study returned to work 2 months on average after completing their treatment, and final measurement was on average 10 months later suggesting that it was something to do with being at work that made a difference.

In their discussion, the authors suggest that perhaps those who didn’t return to work were overall less physically active than those who did, compromising their recovery potential. They also note that being out of work is known to be associated with poorer mental health, so perhaps that explains the difference at the end of the trial period. In addition, they point out that perhaps ongoing stress related to having to handle disability claims processes, perhaps even the financial stress of being unable to work might have been influential.

It’s this last point that I think is interesting. There is no doubt that people who encounter the disability systems that fund their treatment and replace their income feel like their autonomy and independence has gone. They feel their world is being manipulated at the whim of case managers, treatment providers, assessing doctors, and even their family.  A sense of injustice can be detrimental to outcomes for people with whiplash, as Sullivan and colleagues showed some years ago (Sullivan, Thibault, Simmonds, Milioto et al 2009), and we know also that social judgements made about people who experience persistent pain are often negative and exert an influence on the experience of pain itself (Bliss, 2016; Schneider et al, 2016).

Working is really important to people – even in a job you don’t especially enjoy, there are important reasons you keep going (even if it’s only for the money! Money in the hand means food for you and yours, power for the lighting and heating, and even a little bit left over for jam on your bread!). In addition to the money, the most commonly asked question when you’re introduced to someone is “and what do you do for a job?” It’s a way of categorising a person, as much as we hate that idea. Work gives us social contact, routine, purpose and allows us a way to demonstrate competence. Without the anchor of working, many people who live with persistent pain feel the burden of social judgement “who are you?”, of ongoing bureaucracy (filling in paperwork), of repeated assessments to justify not being at work, of constantly being asked to attend appointments, of never feeling like time is their own. Balancing the demands of a system that judges you negatively because you are “unfit” against the demands of family and your own needs is an incredibly difficult process – but then again, so is the process of returning to a job where you fear you’ll fail and experience That Pain Again, and where, if you fail, you could lose that job entirely.

I don’t have an answer to how we can make this process easier. I do know that early return to work can be positive if handled well – but handled poorly, can be an extremely unpleasant and stressful process. Vocational rehabilitation providers need to understand both acute and persistent pain. They also need to carefully assess the psychosocial aspects of a job, not just the biomechanical demands. And someone needs to represent the needs of the person living with persistent pain and help them balance these demands carefully.


Bliss, Tim VP, et al. (2016)”Synaptic plasticity in the anterior cingulate cortex in acute and chronic pain.” Nature Reviews Neuroscience .

De Ruddere, Lies, et al. (2016)”Patients are socially excluded when their pain has no medical explanation.” The Journal of Pain 17.9 : 1028-1035.

McParland, J. L., & Eccleston, C. (2013). “It’s not fair”: Social justice appraisals in the context of chronic pain. Current Directions in Psychological Science, 22(6), 484-489.

Schneider, Peggy, et al. “Adolescent social rejection alters pain processing in a CB1 receptor dependent manner.” European Neuropsychopharmacology 26.7 (2016): 1201-1212.

Sullivan, M. J., Thibault, P., Simmonds, M. J., Milioto, M., Cantin, A. P., Velly, A. M., . . . Velly, A. M. (2009). Pain, perceived injustice and the persistence of post-traumatic stress symptoms during the course of rehabilitation for whiplash injuries. Pain, 145(3), 325-331.

Sullivan, M., Adams, H., Thibault, P., Moore, E., Carriere, J. S., & Larivière, C. (2017). Return to work helps maintain treatment gains in the rehabilitation of whiplash injury. Pain, 158(5), 980-987. doi:10.1097/j.pain.0000000000000871

Mulling over the pain management vs pain reduction divide

I’ve worked in persistent pain management for most of my career. This means I am biased towards pain management. At times this creates tension when I begin talking to clinicians who work in acute or subacute musculoskeletal pain, because they wonder whether what I talk about is relevant to them. After all, why would someone need to know about ongoing management when hopefully their pain will completely go?

I have sympathy for this position – for many people, a bout of tendonosis, or a strained muscle or even radicular pain can ebb away, leaving the person feeling as good as new. While it might take a few months for these pain problems to settle, in many instances there’s not too much need for long-term changes in how the person lives their life.

On the other hand, there are many, many people who either don’t have simple musculoskeletal problems (ie they’re complicated by other health conditions, or they have concurrent issues that make dealing with pain a bit of a challenge), or they have conditions that simply do not resolve. Good examples of these include osteoarthritis (hip, knee, shoulder, thumbs, fingers) and grumbly old lower back pain, or peripheral neuropathy (diabetic or otherwise). In these cases the potential for pain to carry on is very present, and I sometimes wonder how well we are set up to help them.

Let’s take the case of osteoarthritis. Because our overall population is aging, and because of, perhaps, obesity and inactivity, osteoarthritis of the knee is becoming a problem. People can develop OA knee early in their life after sustaining trauma to the knee (those rugby tackles, falling off motorcycles, falling off horses, running injuries), or later in life as they age – so OA knee is a problem of middle to later age. People living with knee OA describe being concerned about pain, especially pain that goes on after they’ve stopped activities; they’re worried about walking, bending and maintaining independence – and are kinda pessimistic about the future thinking that  “in 10 years their health would be worse and their arthritis would be a major problem” (Burks, 2002).

To someone living with osteoarthritis, especially knee osteoarthritis, it can seem that there is only one solution: get a knee replacement. People are told that knee replacements are a good thing, but also warned that knee replacements shouldn’t be done “too soon”, leaving them feeling a bit stranded (Demierre, Castelao & Piot-Ziegler, 2011). Conversations about osteoarthritis are not prioritised in healthcare consultations – in part because people with knee osteoarthritis believe that knee pain is “just part of normal aging”, that there’s little to be done about it, and medications are thought to be unpleasant and not especially helpful (Jinks, Ong & Richardson, 2007).

I wonder how many healthcare professionals feel the same as the participants in the studies I’ve cited above. Do we think that knee OA is just something to “live with” because the problem is just part of old age, there’s an eventual solution, and meanwhile there’s not a lot we can do about it?

When I think about our approach to managing the pain of osteoarthritis, I also wonder about our approach to other pains that don’t settle the way we think they should. Is part of our reluctance to talk about pain that persists because we don’t feel we know enough to help? Or that we feel we’ve failed? Or that it’s just part of life and people should just get on with it? Is it about our feelings of powerlessness?

In the flush of enthusiasm for explaining the mechanisms of pain neurobiology, have we become somewhat insensitive to what it feels like to be on the receiving end when the “education” doesn’t reduce pain? And what do we do when our efforts to reduce pain fail to produce the kind of results we hope for? And the critical point, when do we begin talking about adapting to living well alongside pain?

What does a conversation about learning to adapt to pain look like – or do we just quietly let the person stop coming to see us once we establish their pain isn’t subsiding? I rather fancy it might be the latter.

Here’s a couple of thoughts about how we might broach the subject of learning to live with persistent pain rather than focusing exclusively on reducing pain:

  • “What would you be doing if pain was less of a problem?” My old standby because in talking about this I can begin to see underlying values and valued activities that I can help the person look at starting, albeit maybe doing them differently.
  • “What do you think are the chances of this pain completely going away?” Some might say this is about expectancy and I’m setting up a “nocebic” effect, but I argue that understanding the person’s own perspective is helpful. And sometimes, when a person has persistent pain and a diagnosis like osteoarthritis, their appraisal is less about catastrophising and more about holding a realistic view about their own body. It’s not about the appraisal – it’s about what we do about this. And we can use this perspective to built confidence and increase the importance of learning coping strategies.
  • “If I could show you some ways to deal with pain fluctuations, would you be interested in learning more?” All episodes of pain that persists will have times when pain is more intense than others – flare-ups are a normal part of recovering from, and living with persistent pain. Everyone needs to know some ways of going with, being flexible about or coping with flare-ups. I teach people not to focus exclusively on reducing pain during these flare-up periods. This is because even during rehabilitation we don’t want to use pain as a guide (it can be a cruel task-master). We know that rehabilitation can increase (temporarily) pain while the body habituates to new movement patterns, the brain gets used to new input, and the homunculus gets redefined. It’s great to be able to teach strategies that increase the sense of safety, security and down-regulation that can be lost in the initial onslaught of pain.

To summarise, not all pain problems settle. We can help everyone to be more resilient if we begin talking about ways of coping with flare-ups even during subacute pain, particularly if we avoid an excessive focus on trying to avoid them. Instead, we can begin to help people feel confident that flare-ups always settle down, and that they can manage them effectively by using effective self management.


Burks, K. (2002). Health concerns of men with osteoarthritis of the knee. Orthopaedic Nursing, 21(4), 28-34.

Cohen, E., & Lee, Y. C. (2015). A mechanism-based approach to the management of osteoarthritis pain. Current Osteoporosis Reports, 13(6), 399-406.

Demierre, M., Castelao, E., & Piot-Ziegler, C. (2011). The long and painful path towards arthroplasty: A qualitative study. J Health Psychol, 16(4), 549-560. doi:10.1177/1359105310385365

Jinks, C., Ong, B. N., & Richardson, J. (2007). A mixed methods study to investigate needs assessment for knee pain and disability: Population and individual perspectives. BMC Musculoskeletal Disorders, 8, 59.

Is central sensitisation really a thing?

It seems odd to me that there’s much argument about central sensitisation in pain circles. I thought the idea of central sensitisation was well-established based on research from some years ago – but apparently there are still arguments about its relevance, and lots of debate about how to identify it clinically. This post is based mainly on a presentation by Jo Nijs from Pain in Motion, at the recent NZ Pain Society meeting in Nelson. In this post I want to briefly review the material presented by Jo suggesting that central sensitisation is a thing. I’ll write more about assessment in a future blog, or this post will be the longest ever!

Firstly, what is it and why should it matter? Researchers have long been aware that when a nerve is repeatedly stimulated, in future stimulation it will respond for longer and with more intensity – this is called long-term potentiation. Recently, the contribution of glial cells to this situation has been identified (remember glia? Those little cells whose purpose no-one really knew? Turns out they release gliotransmitters that circulate throughout the spinal cord and allow information to be transmitted widely, far from the original source of stimulation – see Kronschlager, Drdla-Schutting, Gassner, Honsek et al, (2016). Glial cells occur widely throughout the central nervous system, and while LTP is a process we’ve known about in the CNS for some time – we’ve known because this is how “memories” are formed (remember “nerves that fire together wire together”? Pathways that frequently activate develop the tendency to continue to activate together) – we’ve perhaps not been aware that this occurs in the spinal cord as well. So, LTP occurs in both the spinal cord and the brain, and there is more than one way this process is facilitated. Glial cells are one. Central sensitisation involves this process of long-term potentiation across and amongst pathways within our nervous system – it means information from peripheral regions like your big toe are more likely to be transmitted to areas in the brain responsible for attending and responding to threatening information.

Why does this matter? Well, if we think of ourselves as a finely tuned homeostatic machine, one that wants to remain in a stable state, we can think of two systems balanced with one another. One system works to facilitate information transmission (nociceptive facilitation), while the other works to reduce or modulate this transmission (endogenous hypoalgesia). If we continue with the machine analogy, we want to know about “trouble” as soon as possible – so our nociceptive facilitatory system is like an accelerator, working promptly to make sure we know about the state of play very quickly. If you’ve ever driven a race car, you’ll know how twitchy the accelerators are! The brakes on this system is our endogenous opioid system which reduces the influence of the nociceptive system so we can keep moving forward. If the brakes fail, for whatever reason, in a race car we’ll burst forward! Similarly, if the endogenous modulatory system fails, for whatever reason, far more information ascends to relevant regions in the brain for interpretation – and ouch.

What sorts of things enhance connectivity between areas of the brain that deal with nociceptive information? Well, this is where things get all woolly and psychosocial for a while (sorry guys!). From many fMRI studies, it’s possible to establish that “pain catastrophising” or the tendency to brood on pain, feel helpless about it, and regard the pain as seriously intense activates brain areas like the dorsolateral prefrontal cortex, the anterior cingulate cortex, and the insula, which in term reduces the efficiency of the opioid analgesic system (that endogenous opioid system), makes it harder to distract attention from the pain, and increases facilitation (ie the transmission of nociceptive information from lower CNS to higher). In other words, this very psychological construct has a biological component to it.

Central sensitisation has been identified in many different pain problems, ranging from osteoarthritis in the knee (Akinci, Al Shaker, Chang, et al, 2016), post-cancer pain (Lam, 2016), shoulder pain (Sanchis, lluch, Nijs, Struyf & Kangasperko, 2015), and yes, those messy complicated ones like whiplash (Coppieters, Ickmans, Cagnie, Nijs, et al, 2015), low back pain (Sanzarello, Merlini, Rosa, Perrone et al, 2016) and fibromyalgia (Walitt, Ceko, Gracely & Gracely, 2016). Rates of central sensitisation vary from 10% in shoulder pain to 100% in fibromyalgia. For some good reading on central sensitisation in these disorders, take a look at the references I’ve cited.

So yes, central sensitisation is a thing, and it results in increased pain experiences that last longer and spread. Why do some people experience while others don’t? Now we’re venturing into rather more speculative areas, but some findings seem clinically useful. People who have, in their early years, experienced physical and/or psychological trauma, those who tend to catastrophise or have unhelpful beliefs (often inaccurate beliefs) about their pain,  those who have poor sleep, and those who have an elevated stress response seem more likely to have pain that fits with what we’d expect with central sensitisation (See Nijs & Ickmans, 2014).

Why does this occur? Well, stress increases release of glutamate and this in turn increases CNS excitability (makes sense – let’s react faster to everything, at least for a short time). At the same time, stress reduces GABA and serotonin, and as a result inhibition is reduced (the brakes come off). If we add microglial activity to the mix (remember that’s going to increase the connectivity between neurones), and if we add ongoing release of adrenaline in because the stress has been continuing for a while, we’re going to end up with activated glial activity in the prefrontal cortex, amygdala and hippocampus, all important areas for detecting salience and making decisions to act. These glial cells release chemicals known to increase neuroinflammation, reducing hippocampal activity (ultimately reducing volume of neurones in this area), increasing the size of the amygdala (which means it’s more capable of responding to threat), and reducing the prefrontal cortex size, reducing the capacity to make considered decisions (Kregel, Meeus, Malfliet et al, 2015). Ew… nasty! In longterm stressful situations, it seems our brains adapt – and not in a helpful way when it comes to experiencing pain. Whatever you do DON’T say to your patients  “Oh and by the way, your back pain means your brain is inflamed and parts of your brain are shrinking” – this is NOT helpful!

Next post I’ll discuss assessing for central sensitisation – but before I do, remember that central sensitisation is not the only factor at play in ongoing pain. In fact, some people don’t seem to develop central sensitisation even with ongoing nociception from either disease processes, or inflammation. We don’t really know why. What we do know is that simply treating peripheral nociceptive input when central sensitisation is present may fail to help the person – so keeping an eye out for it is important.


Akinci, A., Al Shaker, M., Chang, M. H., Cheung, C. W., Danilov, A., Jose Duenas, H., . . . Wang, Y. (2016). Predictive factors and clinical biomarkers for treatment in patients with chronic pain caused by osteoarthritis with a central sensitisation component. International Journal of Clinical Practice, 70(1), 31-44.

Coppieters, I., Ickmans, K., Cagnie, B., Nijs, J., De Pauw, R., Noten, S., & Meeus, M. (2015). Cognitive performance is related to central sensitization and health-related quality of life in patients with chronic whiplash-associated disorders and fibromyalgia. Pain Physician, 18(3), E389-401.

Kregel, J., Meeus, M., Malfliet, A., Dolphens, M., Danneels, L., Nijs, J., & Cagnie, B. (2015). Structural and functional brain abnormalities in chronic low back pain: A systematic review☆. Paper presented at the Seminars in arthritis and rheumatism.

Kronschläger, M. T., Drdla-Schutting, R., Gassner, M., Honsek, S. D., Teuchmann, H. L., & Sandkühler, J. (2016). Gliogenic ltp spreads widely in nociceptive pathways. Science, 354(6316), 1144-1148. doi:10.1126/science.aah5715

Lam, D. K. (2016). Emerging factors in the progression of cancer-related pain. Pain Management, 6(5), 487-496.

Nijs, J., & Ickmans, K. (2014). Chronic whiplash-associated disorders: To exercise or not? The Lancet, 384(9938), 109-111.

Sanchis, M. N., Lluch, E., Nijs, J., Struyf, F., & Kangasperko, M. (2015). The role of central sensitization in shoulder pain: A systematic literature review. Seminars in Arthritis & Rheumatism, 44(6), 710-716.

Sanzarello, I., Merlini, L., Rosa, M. A., Perrone, M., Frugiuele, J., Borghi, R., & Faldini, C. (2016). Central sensitization in chronic low back pain: A narrative review. Journal of Back & Musculoskeletal Rehabilitation, 29(4), 625-633.
Walitt, B., Ceko, M., Gracely, J. L., & Gracely, R. H. (2016). Neuroimaging of central sensitivity syndromes: Key insights from the scientific literature. Current Rheumatology Reviews, 12(1), 55-87.

End-of-year musings

It’s my last post for the year. It has been an extraordinary year, lots of surprises, shocks and enough excitement for anyone! I’m not even going to start on the political changes, here in NZ we’ve had yet another major earthquake, excitement as ACC (our national accident insurer) sets up new pain service contracts (with a LOT of people who haven’t been involved in pain management before… there’s an experiment in the making!), and continuing road cone carnage on the streets of Christchurch.

On the pain news front, I can’t think of any incredibly ground-breaking news – although one medic advised that “Virtually all cases of low back pain can now be diagnosed definitively by criterion standard methods as to source and cause.” That same medic also argued that a paper by Maher, Underwood & Buchbinder (2016) on non-specific low back pain, published in The Lancet, represented “the views of non-evidence-based troglodytes who (a) have apparently not read any scientific papers since 1966, and (b) have vested interests in “managing” non-diagnosed patients so their practices remain busy and they reinforce each other’s views that the burden of low back pain cannot be eased.” I’ll leave the critiquing of that view to those with more time and energy than I have!

It’s also been a year in which various commentators have critiqued the “biopsychosocial model” as it’s applied in musculoskeletal pain.  Some have pointed out that this is an unscientific model, it’s not a theory that can be tested and therefore can’t point to “truth” or whatever approximation we can currently identify. Others have argued that by adopting this framework, practitioners must either be versed in “life, the universe and everything” – or perhaps become exactly what advocates of this approach decry: reductionists. I’m not sure I follow this argument, but those that raise it are intelligent, articulate and far more thoughtful than those who believe that Maher, Underwood & Buchbinder are “troglodytes” or have “vested interests”.

I continue to hold that a biopsychosocial perspective explains more, and is of practical use when we consider the various factors that might influence why this person is presenting in this way at this time, and what might be done to reduce their distress and disability. Here’s my take.

Biopsychosocial model

When we look into the original biopsychosocial model, we need to understand the context in which Engel first developed it. He was a psychiatrist, and at the time psychiatry was under threat from psychologists in particular, who were strongly advocating that many mental illnesses were actually “problems of living”. Things like alcohol abuse, forms of mood disorder, relationship issues and the like were seen as disorders influenced by learning and environment rather than biology. Psychiatrists were perhaps on the way to being sidelined from the very area in which they claim expertise. Engel, influenced by general systems theory and cybernetics, proposed a way for psychiatrists to remain relevant: look at the person as part of a wider system in which each element in the system could influence and be influenced by the next. Engel used this approach as a way to frame conversations with the patients he saw – attempting to understand how and why they were seeking help, and especially, attempting to understand the person and his or her priorities. I think that’s admirable.

How the model has evolved since then is an interesting tale. I first encountered the model during my occupational therapy training, where it was a foundation to viewing people-in-context. It was presented as a bit old hat (I started training in 1979), and was replaced in my profession by Gary Kielhofner’s Model of Human Occupation. This model similarly draws on general systems theory, and argues for the relevance of volition and habits as well as capacity from a biological/performance stance to undertake occupation and of course, contexts such as environment which includes the social environment. MOHO incorporates much of what we consider to be biopsychosocial – in fact, occupational therapy as a profession is based on the idea that people actively engage in purposeful and meaningful activities (occupations) that are formed out of the affordances available to them by virtue of biology, psychology and social elements within an environmental context.

So what?

For a model, or theory, to have value it needs to offer something that existing models or theories don’t. It needs to be more parsimonious (make fewer assumptions), explain more (be more consilient), hold together with existing knowledge (cohere), and predict more (Thagard, 1978).

For a clinician, a theory must also be useful in terms of explaining why this person is presenting in this way at this time, and directing what can be done to reduce distress and disability. Why these questions? Because people actively make decisions to seek treatment. They evaluate their experience in light of their past experiences, prevailing community beliefs about the trajectory of their problem, family influences, and yes, legislative influences. These are possibly more important than the biology of their problem – because we’re not going to treat someone who doesn’t believe they have a problem!

As clinicians I think we need to ponder exactly what we consider to be “treatment”.

When my fracture is reduced and immobilised, that is “treatment” – but it’s not actually ‘healing’ my bones, it’s actually up to my body to do the work. What immobilisation does is create an environment in which my body can heal itself. But the problem of a broken bone is not “treated” just by immobilisation. Treatment has to include the rest of my recovery – and involve prevention strategies too. My recovery will need to include restoring function. And some of that restoration will be by guiding me through various movements that increase tissue tolerance as well as my confidence that my limb will support me. My recovery also has to include me understanding and learning from my experience – will I jump off that cliff again? Will I leave the toys all over the floor again? Will I walk on a slippery path again?

I think clinicians simply create an environment in which people can recover. And we need to go beyond measuring range of movement or strength to establish that recovery has occurred. Recovery isn’t just about returning to “normal” whatever that is. It’s about moving beyond this interruption and into new possibilities and new challenges. It’s really about being able to be who we really are. While that’s primarily the person’s own responsibility, our job as clinicians is to create an environment where it’s possible. While a biopsychosocial model/theory/framework makes life complex, using this approach allows us to be aware of more of the factors relevant to recovery and growth than simply looking at people as if they’re bits of meat, bone, and juice.

In the new year

I’ve been blogging since 2007. In that time I’ve written over a thousand posts all on the topic of pain. Almost all of my posts are on the theme of how we can remember that we are working with people. Other human beings who have their own thoughts, beliefs and priorities. Humans who make sense of their situation as best they can. People who, like us, hold cognitive biases, and feel emotions, and get stuck, and hold values. My real focus is on how we can integrate these things into clinical reasoning – because until we do, we’re ignoring what matters most to the people we seek to serve.


Engel, G. L. (1977). The need for a new medical model: A challenge for biomedicine. Science, 196(4286), 129-136. doi:10.1126/science.847460

Maher, C., Underwood, M., & Buchbinder, R. (2016). Non-specific low back pain.  The Lancet. doi:10.1016/S0140-6736(16)30970-9

Thagard, P. R. (1978). The best explanation: Criteria for theory choice. The Journal of Philosophy, 75(2), 76-92.