Photo Credit: Tom Rouse

Last week we discussed how and why you can’t have a slipped disc, and that if you injure your disc your body does an awesome job of healing itself. (If you missed it, you can check it out here).

Today we are going to discuss how you can still have pain even if your body has recovered from an injury, and the pain you experience does not necessarily correlate with the level of tissue damage in your back.  To understand this, we need to understand how pain and tissue damage are not the same thing. Pain is response/output from the brain based on the interpretation of complex multifactorial inputs from many of our bodies systems. Our brain processes information from all our systems and decides on the most appropriate response.

In relation to your disc injury in your back, if the injury is significant enough there will be some local tissue damage, you might have damaged some of the collagen fibres that make up the disc (Remember not to worry, your body will fix that). Information about that local tissue damage be will sent from the free nerve endings that surround the tissue to the brain. If there is some local inflammation due to injury, chemical receptors will send this information to the brain. If the tissue is stretched or compressed due to the injury this information will also be sent to the brain. Notice how none of this information is a “pain” message. It is all just information being sent from a local tissue to the brain. Pain is the output. Your brain takes all this information and decides whether a pain response is necessary. However, things aren’t so simple. This output is not only reliant on what is happening at the local tissue level at the area of injury, your brain is also processing information from everywhere else in the body to help it decide on the most appropriate response. It uses environmental information, emotional information, information regarding the location of the injury and many more to decide whether pain is the appropriate output. This means that work stress can influence your pain, and anxiety from wondering whether your back will ever get better can influence your pain. A good book if you want to read more on this topic is ‘Explain Pain’ by Dr David S. Butler and Prof G. Lorimer Moseley.

There are numerous examples of situations where people have experienced significant trauma but at the time of injury have not felt any pain. You might have some of your own examples, but one that sticks in my mind in an elderly gentleman who was having a chest x-ray for some breathing problems. When they x-rayed his chest, the radiographer asked the gentleman about the bullet lodged in his neck. He was confused as he had no memory of ever being shot. After further questioning he revealed that he had several tours of active duty in the war and can vaguely remember a small cut that had to be stitched up, but in his words “it was nothing”.

Now I know what you are thinking, how can someone not know that they have been shot. I promise you this is not an isolated incident, and this old gentleman is not superhuman. This is an example of our brain taking all the available information and making the decision that in that specific moment pain would have been an inappropriate output.  Yes, there would have undoubtedly been tissue damage to the skin, muscles and bone, there would be local inflammation, this information would have been sent to the brain. But now consider the bigger picture, the soldier’s life was in danger, he was in the middle of a battle that required his full concentration, his brain made the choice that pain would not have been an appropriate response in the current situation, as survival was more important. He could not afford to waste time and energy worrying about pain. His brain decided to supress this information to allow him to continue in the battle.

The above story is an extreme example, but we have all experienced similar episodes to a lesser extent, the football injury that you don’t notice till later in the evening, the ankle sprain that only hurt after you have finished the game. On the other end of the scale, have you ever wondered why a small paper cut on the finger is so painful? For such a small amount of tissue damage it doesn’t half hurt. These examples underline the fact that pain is not related to tissue damage, pain is a much more complicated multifactorial output and it’s about time we start treating it that way.

But if we can’t rely on pain to tell us how much damage has been caused then how are we supposed to know how to respond? That I suppose is my point, we shouldn’t let pain be our only guide. Pain in relation to back injuries is not a good predictor for injury severity. This doesn’t mean that you should ignore your pain and just push through irrespectively, but on the flip side it doesn’t mean that you need to stop something as soon as it becomes painful. We hope you see this as a release from the shackles of your back pain. If we can move past worrying about pain being related to tissue damage, we can start looking at pain and movement in a different light. Each time you move your back it is not causing more damage, you are giving your back what it needs to recover. We need to remove the fear of movement to allow our back to fully recover.

A simple exercise that can help underline this point is breathing. We know that taking slow deep abdominal breathes has a positive effect on stress anxiety, helps to calm the nervous system, and will help to relax a lot of the muscles that can become overactive because of your back pain. A good starting point for you to managing your back pain is to practice some slow deep abdominal breaths. If you can find a comfortable position where you aren’t being distracted and can relax into the exercise, then this will give the best results. We know it sounds a bit strange but give it a go, what have you got to lose?

Pain is a very complicated topic and we have only just scratched the surface here. For further reading check out our earlier blog ‘pain is good’ and keep an eye out for future blogs as this is something we think is important to discuss.

Moving Away From a Structural Model of Back Pain

One of the amazing advances in medical imaging over the past 20 years has been the MRI scan. These scans continually improve our views of the nature of disc injuries and the severity of the local tissue damage. This has been a double-edged sword. We are getting better and better at finding local tissue damage, but we are struggling to determine how much this local tissue damage is correlated to our experience of back pain. There have been numerous studies that have highlighted this issue. These studies have looked at asymptomatic participants (people with no back pain), they have found that most subjects have some degree of disc pathology. This ranged from minor disc bulges to major disc extrusions. These studies point to one of the issues with MRI scans, if people without back pain have disc pathologies how can we say with confidence that the disc pathologies we see when we scan people with back pain are the cause of the pain. This is not meant to throw doubt over the value of MRI scans in the diagnosis of lower back pain. Rather it should be a positive way to view the results from your scan. We have discussed this before in our blog ’X-rays and Instagram- how are they the same’.

If a large majority of the population are walking around with disc pathologies, there is no reason you cannot recover from your disc injury. When looking at planning treatment for your disc injury the results from these studies should give confidence that we don’t have to wait for the disc pathology to recover before starting rehabilitation, and that the resolution of your pain is not linked to the change in your scan results. With a little help from Sports Lab we will be able to guide you along the right path to ensure that that you make a full recovery from your back injury.

Richard Linley is a senior Sports Lab Physiotherapist. He has extensive knowledge in major trauma, and both acute and chronic care. Have you heard the whispers that Rich is also a dirty hippie.