Let's talk about phantom pain

Richard Holt 7 June 2022

What is phantom pain, how does chronic pain work and what determines our individual pain tolerance? Richard Holt sets out to find the answers

Of all the sensations we can feel, pain shouts the loudest. A tender touch, a delicious taste or a beautiful sound—these are all silenced instantly by a stab of pain. It makes the most noise because it has the most urgent job to do, to protect you from harm. Without pain in our lives how would we know to pull our hand back quickly from a fire, or rest an ankle while it heals?  

For the rare few born with a congenital insensitivity to pain, their lack of suffering is more than outweighed by the constant peril of injury, simply because they don’t have the pain-sharpened sense to keep out of harm’s way.  

So, what is chronic pain?

Man with back ache sitting at desk

As a sufferer of chronic pain following a double-ankle break fourteen years ago, I’m aware that pain has an important survival advantage, but only when pain is sending us signals that require action—and these signals can go wrong. Phantom limb pain is very well documented. This is when patients feel pain in amputated limbs, as their severed nerve endings continue to send distress signals to their brains.  

Today, doctors have great success treating amputees with phantom pain by combining pain relief medication with more cutting-edge treatments, like electrical stimulation of the brain and spinal cord. Together this process retrains the nervous system to stop sending unnecessary signals. Could something similar be offered to able-bodied people suffering chronic pain? 

"When pain is no longer useful, it is just, well, a pain"

It is obviously not useful for an amputated limb to hurt, but what if your bad back, or dodgy knee is sending pain signals for an injury that no longer exists? Pain often starts with an injury, like a broken bone or a torn ligament. But in many cases it continues long after the tissue has healed. This means a lot of us could be suffering from a form of phantom pain. And when pain is no longer useful, it is just, well, a pain. 

Chronic high

Pain is defined as chronic when it persists once the usual process of healing has finished, generally after around three months. Why some people go on to develop chronic pain while others don’t is the biggest question troubling pain specialists. The scale of the problem is staggering, with studies saying that around a third of people will experience chronic pain at some stage in their lives. So while pain may be caused by injury or illness initially, chronic pain is now recognised as a condition in its own right, causing a great deal of lost productivity and human suffering. 

“It is important to stress that a patient’s experience is real. Any pain is genuine and it is never helpful to be told otherwise,” said Dr Jonathan Rajan, a consultant anaesthetist specialising in pain medicine at the OrthTeam centre. The question is, what is causing the pain and if it is unhelpful, what can be done to dial it down, or even tune it out completely?  

Woman with headache

The first thing to do is break down the association of cause and effect. It has long been known that we experience pain subjectively—two people can suffer an identical injury and report very different levels of pain. But less well explored is the fact that one person can report very different levels of pain from one day to the next, or even one minute to the next.  

The fact that someone’s back may hurt one minute and not hurt the next tells us something important about pain. If it was simply reporting an injury, the pain would be more consistent. But pain is affected by a combination of what specialists call the bio/psycho/social model—that is to say it can be traced to a mix of biological, psychological and social factors. Put simply, pain is felt very differently according to what else is going on in a person’s life. You may have intermittent knee pain, for example, but if you are also experiencing emotional trauma and social isolation, this is likely to have an amplifying effect on the pain levels that you feel. 

"Put simply, pain is felt very differently according to what else is going on in a person’s life"

Armed with this knowledge, it is possible to start approaching pain with a different mindset. Because if we put too much emphasis on the biological causes of pain, we can ignore the huge benefits that can be gained from addressing the other things in your life that may be making the problem worse. 

“In patients suffering chronic pain there is a very poor correlation between pain and tissue damage,” Dr Rajan added. “It doesn’t mean that a person won’t have any tissue damage, but it often doesn’t correlate with the pain response. On an MRI scan, most over 30s will show tissue damage in their joints from normal wear and tear, but that doesn’t mean they will feel all pain.” 

Doctor sharing an MRI scan

The conundrum for pain specialists is understanding the cause of a pain in patients who report symptoms that may not fit with any of their clinical assessments. Sometimes a patient will feel pain because of what he calls a “software issue”. So in simple terms, you break a bone—the hardware—and the bone heals but for some reason the distress signals continue.

“When I refer to software, I mean the systems that we might not pick up on a scan, like nerve impulses and changes in blood flow,” Dr Rajan said. “Changes in neural signaling after an injury or an illness can result in patients getting pain that is completely out of proportion with the damage. So in extreme cases a light touch to the skin can be picked up by an overly sensitive system as pain signals to the brain.” 

A sensitive issue

The question is, when the system has become too sensitive, what can you do about it? Dr Sunil Arora is a consultant in anaesthetics and pain at Frimley Park Hospital, where he manages acute, chronic and cancer pain. The first thing to do, according to Dr Arora, is to identify whether the issue can be tracked down to a specific part of the nervous system. Doctors can try injecting local anaesthetic to different regions, as well as using spinal cord stimulators to treat back and neck pain. Similar to the treatment for phantom limb pain, this can help retrain nerves to function more normally and therefore cause less pain.  

Often, though, you can rule out both tissue damage and over-sensitive neural pathways as the main causes of pain, then you have to look at retraining the brain. And a lot of that is down to us.

"The worst thing about pain is that it makes people feel fragile, like we need to do less"

“Traditional medicine will see something broken and try to fix it,” Dr Arora said. “But we are discovering more and more about the brain’s tremendous capacity to adapt. So of course medical interventions are there when people need them. But also as individuals we have a huge ability to affect our pain outcomes with a whole range of activities like yoga and mindfulness, as well as the usual good health practices of socialising, eating well and getting enough sleep.” 

The difficulty for doctors is that patients expect them to fix the problem like a mechanic fixes a car. They don’t always want to be told that they have to do a lot of the work themselves. But while we are only just starting to understand the complexities of how the brain responds to pain, one thing is clear. How we move, rest, eat and sleep makes a huge difference to the levels of pain we feel. You should always seek medical advice if you are unsure about starting a new exercise programme, but provided you are not going to exacerbate an existing condition, the best advice is to move as much as your body allows, reduce stress, sleep well and eat as well as you can.  

Woman in a yoga class

The worst thing about pain is that it makes people feel fragile, like we need to do less.  

And as we do less over time, our bodies become weaker and subject to more injury and more pain. But generally we are robust and adaptable, not fragile. So once an injury has healed the best thing in most cases is to get back to using your body like before. The quicker you do this the more likely you are to heal properly without long-term pain. Chronic pain is a massive problem for so many people. The pain is real, but the chances are most people have the power to turn the noise down a fair bit and start enjoying life like before.  

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