The hurt locker: How our minds can successfully control chronic painby Donna Chisholm
Patients in chronic pain are having repeated, futile operations when better access to specialist pain services could ease their suffering.
Love, 49, knows pain. Six weeks of radiotherapy, after surgery on a squamous cell carcinoma at the base of his tongue in 2011, caused nerve damage and, much later, chronic pain that left him taking so many tablets – 87 a day, including morphine, anti-inflammatories and anti-emetics – that he had to use a spreadsheet to keep track of them. Ultimately, he was so befuddled by painkillers that he couldn’t even remember what he’d said seconds after saying it. “I couldn’t function. I was just sitting here wallowing in pain.”
One day early last year, he woke at 2am to the worst pain he’d ever had. “It was like I had stuck my finger in the power socket and I was being shocked.”
It’s difficult to describe Love as lucky. He has so much trouble swallowing he’s had a feeding tube inserted into his chest that delivers nutrients from the 1.5-litre packs of Nutrison he carries around in a backpack. Without it, he struggles to keep his weight above 50kg. He’s unable to work. He will require invasive and extensive reconstruction of the bones in his jaw, which are slowly dying because their oxygen supply was so compromised by his treatment.
But lucky he is. Of New Zealand’s roughly 770,000 people with chronic pain, he was one of only about 2000 new patients able to access hospital-level pain services nationally in 2018. New Zealand has only three specialist centres, in Auckland, Wellington and at Burwood in Christchurch. The disparity in supply and demand and estimated total cost of chronic pain of up to $15 billion a year were highlighted in a report to the Australian and New Zealand College of Anaesthetists faculty of pain medicine, which was published last month by consultants Sapere Research Group. The faculty is now pushing for more funding for pain-specialist training places, saying multidisciplinary management more than doubles return-to-work rates for patients and substantially reduces opiate use and annual medical costs.
Love, for example, now needs to take only an occasional Panadol and can discuss the stirrings of pain in his right shoulder with something approaching academic interest. He cycles for an hour a day and, mostly, he is pain-free. He learnt that his pain, after so long, was no longer useful or protective – the reasons we experience pain in the first place. Nor was it “all in the mind”. His brain and nervous system had effectively learnt how to produce pain all by themselves – with no external stimulus or conscious help from him.
Leaving the volume on high
Pain specialist Tipu Aamir, head of the Auckland Regional Pain Service (Tarps), which treated Love, explains it this way: “Years ago, when there weren’t many mobile phones, we had to learn a new landline number if we moved suburbs. The first few times, we couldn’t remember it, but after recalling it 20 or 30 times, it pops into the brain with no effort at all. It’s the same with pain signals. At first, they fire in response to a stimulus, such as the nerve damage from Love’s radiotherapy, but if they do it often enough, it comes automatically. The track that is taking that signal has transmitted it so many times that it becomes hypersensitive, so the pain response is elicited even when there’s no pain to respond to. Mostly, pain starts as a result of disease or trauma.”
Pain has many functions, says Aamir, but the two key roles are protective and recuperative. “If you’ve injured your wrist and you keep moving it, it’s going to get worse. The purpose of pain is to let you know something is wrong and to prevent more damage.” But when the injury heals or the disease is cured and the pain goes on, it’s neither protective nor recuperative.
And when the brain focuses on that pain – as Love’s did when he was describing it during our interview – it kicks back into action and has to be, effectively, put back to sleep. Neuropathic pain like his, caused by nerve damage, is less common than other sorts of pain – it occurs in about 15% of Tarps’ patients and is harder to treat successfully.
Neuropathic pain often happens after breast-cancer surgery and in operations in which the chest is opened, when damage to the nerves is difficult to avoid. It’s also common in diabetic neuropathy and multiple sclerosis. A far greater proportion of people develop chronic pain after a musculoskeletal injury or osteoarthritis, conditions in which neuropathic pain is much less prevalent.
In these cases, chronic pain is caused by the nervous system’s dysfunctional response to the pain. Think of it like an electric guitar and amplifier. The guitar strings are the sensors in the peripheral tissue that tell us something is wrong, and the amp – the spinal cord and the brain – can make the sound louder or softer. To make the sound – the pain – louder or more intense, you can either strum the strings harder, by activating the danger signals in the peripheral tissue, or you can turn up the volume on the amp. Usually, when an injury heals, the body turns down the amp by itself. In chronic pain, the volume is left on high – and can affect the perception of pain in other parts of the body. For instance, a patient with knee pain is not only more sensitive to pressure or heat over their knee, but also when it’s applied to their shoulder where they don’t have any pain.
Teaching patients how to turn down the amp, or take their mind off their pain, without prescribing opiates is a cornerstone of the pain-service role. Although about 20% of patients are on opiates when they start, the service hasn’t initiated the medication since 2004. Techniques include hypnosis, or concentrating on changing the intensity of pain.
One method Love has found effective is the switch technique in which he imagines a panel of light switches with a coloured light bulb above each and a wire from each switch to a different body part. He identifies the body part he wants to work with, and the wire that goes to that switch, then he turns off the switch in his imagination and sees the bulb go out.
The former bookshop manager says his pain wakes him like clockwork every morning at 6am, but now, with visualisation, he can shut it down, either by turning off those switches or imagining himself walking on the beach. “The pain just stops.”
The other key part of his recovery has been exercise. “I don’t pretend to know all the answers, but when I first went to the doctor at Tarps and she told me to be active to control pain, I did think she was off her rocker. People just need to have an open mind, to accept that it is possible to control your subconscious yourself. I’m not saying everyone can or will be successful, but a lot more people could get off the drugs if they were willing to accept it. You’ve got to believe. If you have a niggle that it might not really work, it won’t, because that will dominate your subconscious mind. But if you 100% believe you can take control of it, most people can.” He says, in hindsight, he might have been more open to the message because he had realised that his pain often abated when he rode his bike.
Accepting chronic pain
Like many pain patients, Love has struggled with low mood and is on antidepressants. When he “crashed and burned” with depression and was so debilitated he often couldn’t get out of bed, he adopted his poodle Lucky Star. “When I first got him, I could barely walk to the letter box, but I had to walk him. I walked to the letter box the first day, then the first power pole down the street, and the day after that, the next one. He got me moving again.”
Anxiety and depression, and a tendency to catastrophise pain, are often predictors of poorer outcomes, says pain researcher and neurophysiologist Gwyn Lewis of Auckland University of Technology’s health and rehabilitation research institute. So, too, is a history of drug or alcohol abuse and ongoing battles for accident compensation.
“Our emotions can turn pain up and down. We normally modulate pain in different situations. If you are running around playing sport and get a cut, you might not even notice it, whereas if I picked up this bit of paper and gave you a paper cut, you’d probably scream. It’s why, when you are getting a vaccination, the nurse always distracts you and tells you to look out the window. If we pay attention to something, we turn up the pain. Normally, it would be beneficial – it is trying to tell us that there’s something wrong so we are aware of it and can fix it.” Usually, when the injury heals, the body turns down and switches off the pain signal, but in chronic pain, this doesn’t happen.
Some pain services exclude patients with poorer prospects of recovery, but the evidence is conflicting. “If you’re a bad catastrophiser, you have the potential to improve more, but you also might not get back to what we would call a normal level, so it depends how you are measuring your outcomes.”
Other patients who tend not to do as well are those who arrive for pain treatment believing that if they still have pain, it means they must still have a condition causing it that doctors have missed and that’s what needs to be fixed. “They tend to think of their pain as something that is very threatening, ‘my spine is going to crumble’ or ‘I have a brain tumour’,” says Auckland health psychologist and lecturer Debbie Bean, who has spent more than a decade working with pain patients at Tarps. Understanding and accepting the neuroscience of chronic pain are key to managing it, she says.
“You have to accept you have chronic pain. It doesn’t mean accepting that life is terrible and you have to lie on the couch for the rest of your life, but accepting that it’s a problem you’re going to have to deal with. The other part is that you are going to have to be active and develop a good life, so there is a committed-action part of acceptance.”
We also know that depression and anxiety are linked to the body’s inflammatory response, and this could also have a direct effect on the physiology of pain. “There are very interesting functional MRI studies showing that even if you induce depression experimentally, you can measure blood flow changes to the pain-related areas of the brain and people will experience more pain.”
Many patients with chronic back or joint pain have had repeated operations to fix their problem, but they failed, because by that time the pain had a life of its own, unconnected to the original injury. If you’re still in pain three to six months after an original injury, the pain is probably chronic, says Aamir, and “absolutely, the alarm bells should be ringing. By three months, you shouldn’t be on any painkillers, apart from the occasional paracetamol.” Although patients often believe painful movement is harmful, they’re already at the point where it won’t do any more damage and lack of activity is likely to be making their problem worse.
“In general, you need to be really careful with revision surgery,” Aamir says. “When someone has a fracture and has a plate and screw in, if the screw becomes loose or is oversized and is pressing on the nerve, revision surgery might help because it’s irritating at a local level. However, in cases where there’s no obvious cause, sometimes revision surgery can make things worse.”
Patients should ask their surgeon to estimate the odds that the pain will get worse without surgery, or get better with it. “If the odds are 50-50 or less, then people need to think about it, especially if the surgeon who is actually going to do the operation is not fully convinced. Multiple revision surgeries for the same pain, a lot of the time, won’t work.”
Pain specialists, he says, look at the “big picture” after patients have often been to a series of single-discipline specialists and numerous opportunities to tackle chronic pain have been lost. “We can do far better the earlier we recognise it, before the nervous-system changes get really ingrained. It’s no use being referred to various specialties and being maintained on drugs. If a patient is on opiates, and they’re increasing their dosage, that should be a warning that it isn’t right.”
Identifying those at risk
About one in five patients will have persistent pain after knee-joint replacement. Hip replacements have slightly better results, with only about one in seven or eight patients having a poor outcome.
A recent study, co-authored by Lewis and her AUT colleague David Rice, examined 300 patients who had knee replacements to see if they could identify which factors predicted a poorer result. They found they could correctly predict, in two-thirds of cases, those who would still have moderate to severe pain six to 12 months after surgery. Factors that weighed against a good outcome included very-high-intensity pain before surgery, a more sensitised “amplifier” effect in the brain and spinal-cord circuitry, and some psychological factors – people who expected to have more pain after surgery and those who said they were more anxious tended to do worse.
The next step, says Lewis, is to develop an intervention course that patients could do while waiting for elective surgery that could improve their results.
“Psychosocial factors are still a really critical piece of the puzzle here,” says Rice. “Thoughts and emotions [and by extension all the social stressors in our lives that may lead to negative thoughts and emotions] can change how we interpret a given signal in the brain – and therefore how intense and unpleasant the pain experience is – and also help to initiate and maintain the central nervous system changes that underpin chronic pain.
“Our personal experience of pain is that it signals danger or damage to the tissues in our body. So, the default understanding of most people, and indeed many health professionals who aren’t pain specialists, about chronic pain is that there must still be something wrong in whatever body part they hurt and the pain is telling them they are doing more damage. It can be difficult for people to understand that, as the pain persists, the cause is usually no longer a problem in that body part, but largely a problem in the nerve pathways in their spinal cord and brain.”
Rice is also co-supervising a PhD by consultant anaesthetist Daniel Chiang, who is investigating genetic and other factors that may explain why some women go on to develop chronic pain after breast-cancer surgery. “Studies tend to show that, depending on the chronic-pain condition looked at, between 30% and 70% of the risk is genetic. Dozens of genes are potentially involved, each conferring a small amount of risk.”
Chiang will measure some of those genes, and test the sensitivity of the pain system before the women have surgery. About 130 of the 200 study participants have been recruited, and they will be followed for six months after their mastectomy or lumpectomy. He hopes the differences between those who do or don’t have chronic pain will help to identify who is most at risk and what can be done to prevent it.
Pain in context
Bean says the idea that people have a pain threshold has been disproved – people have different tolerance to pain in different settings. Pain history also has a role. “You may have had some positive experiences of coping with something that is supposed to be painful.”
Likewise, childbirth pain is a good example of how the context of pain can affect a woman’s experience of it. “This is one of the things that tells us how people make sense of pain, and why the meaning of pain is so important. Childbirth pain means something really wonderful is happening, there’s a reason for it that is generally considered positive, and it’s going to end. That’s really different from a pain that you think might be a cancer, where it is alarming and might mean you’re going to die.”
Health workers have to work harder to engage patients with those sorts of health fears, says Bean. “We say, ‘This is what we think is going on; we’ll try to teach you a bit about it and why we think this is the case.’ They may negotiate with the doctors for a few extra tests that aren’t necessarily indicated, purely for reassurance.”
Aamir says that after attending the pain service, about 70% of patients are in a better state, although just how much better is a matter of degree. Patients report a 50% reduction in painkiller use in general and a 70% reduction in opiates.
“By the time they come to see us, most patients are still hoping for a cure. Our job is to say to them, ‘We agree with you, we should have something to cure you, but unfortunately this is the state of medical science at the moment. We can’t necessarily get rid of the pain, but there are other ways we can make your life better.’”
Adam Love is one whose life has improved immeasurably. “I am a whole different person. You talk about accepting your new normal – that you are not the person you were. You need to accept what is happening and get on with it. It is easy to say and hard to do. It took me seven years [after cancer treatment] to accept my new normal, but now that I have, I am doing so much better.”
Pain by the numbers
The need is growing, but there aren’t enough pain specialists to go around.
- New Zealand needs about 36 more full-time pain specialists, based on the internationally recommended ratio of one specialist to 100,000 patients, according to a report commissioned by the Australian and New Zealand College of Anaesthetists faculty of pain medicine.
- The National Health Survey of 2016/17 estimates 20% of adults had chronic pain – up three percentage points on a decade earlier. That is defined as pain present almost daily, which has lasted or is expected to last more than six months, irrespective of intensity.
- The prevalence of pain increases with age, from 8% in those aged 15-24, to 35% in people 75-plus.
- Māori (23%) and European/other (22%) have the highest rates of chronic pain, followed by Pasifika (14%) and Asian (11%) adults.
- Chronic pain affects 23% of those in the most-deprived areas, compared with nearly 17% in the least-deprived regions.
- The number of New Zealanders with chronic pain is expected to increase as the population ages to around 1.26 million by 2048.
- Chronic pain is commonly experienced in more than one site. The NZ Chronic Pain Survey, distributed online to doctors, hospitals and pain clinics in 2014, had 142 responses, mostly from women. It found the most common site was the lower back (59%), followed by abdomen (49%), joints (39%), neck (34%), muscle (31%), headache (31%), foot (28%), upper back (23%) and wrist (12%).
- Most of the survey respondents had trouble walking (76%), sleeping (75%), concentrating (64%) and maintaining relationships (56%) because of their pain.
- The annual cost of chronic pain in 2016 was estimated at $13-14.8 billion.
- Patients can often wait up to 60 days before being seen by a specialist pain centre, but some services can have wait times of up to six months.
A patient’s susceptibility to chronic post-surgical pain depends on the type of operation they have had and their underlying vulnerability, say researchers from the University of Western Australia and University of Warwick in the UK.
Stephan Schug and Julie Bruce compiled this list of the incidence, in a report published by PAIN Reports in 2017. They said patients at risk should be assessed and identified pre- and post-operatively so their pain could be better managed.
Type of surgery and the incidence of chronic post-surgical pain:
- Amputation 30-85%
- Caesarean birth 6-55%
- Gall bladder removal 3-50%
- Coronary bypass 30-50%
- Craniotomy 7-30%
- Dental surgery 5-13%
- Hip replacement 27%
- Inguinal hernia 5-63%
- Knee replacement 13-44%
- Melanoma resection 9%
- Mastectomy 11-57%
- Sternotomy 7-17%
- Thoracotomy 5-65%
- Vasectomy 0-37%
Drug of choice
An Auckland trial aims to identify the drugs that work best for people with chronic pain.
Now a new Health Research Council study aims to discover the most effective pain treatments for osteoarthritis, and how clinicians can better predict which patients will respond to which drugs. Neurophysiologist David Rice, a senior lecturer and researcher at the Auckland University of Technology, who works with chronic pain patients at Waitemata Pain Services, aims to recruit more than 140 people for the trial.
The most common pain medicines for osteoarthritis are drugs such as paracetamol and nonsteroidal anti-inflammatories (NSAIDs). But they are not always effective, and not everyone can tolerate the side effects of NSAIDs, so they tend to be prescribed opiates such as tramadol and codeine. “We know there is not really good evidence opiates are effective in the long term and they come with their own risks and problems.”
A class of antidepressant drugs known as serotonin-norepinephrine reuptake inhibitors are a relatively new treatment for patients with osteoarthritis pain. Often used in people with nerve-related pain, they regulate the neural pathways between the brain and the spinal cord that turn the pain signal up or down, blocking the uptake of the neurotransmitters involved and strengthening the nervous system’s ability to turn the pain down. “People with a poor function of this particular pathway should respond to those kinds of medicines, but people whose pain is primarily caused by a signal from the joint might not respond as well and might do better on other things, such as anti-inflammatories.”
A drug that is well tested and often used overseas is duloxetine, which is not funded in New Zealand, but Rice’s study will compare its effectiveness with venlafaxine, the version of the drug funded here. About 30-40% of patients have a strong reaction to duloxetine, reporting at least a 50% reduction in pain, but up to 50% get no clinically meaningful benefit.
Rice will test the pain pathways in osteoarthritis patients before drug treatment to try to work out who will benefit most, and to prevent others for whom it would not be useful from being exposed to the risks and side effects.
This article was first published in the April 20, 2019 issue of the New Zealand Listener.
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