What Happens When We Feel Pain?

If strain is placed on the low back for example, injury to the joints, ligaments, discs or muscle may occur. This may result in sensitisation of pain receptors which supply these structures. Signals then pass along the nerves to the spinal cord and then up and along nerve tracts within the spinal cord to the brain.

Once these pain signals enter the brain they are directed to the sensory cortex which may register the sensation of pain and tells you where it’s coming from. This type of acute pain may be important to help you avoid further injury – i.e. it acts as a warning signal.

With regard back pain, we often identify a specific back pain profile that can easily be misdiagnosed and incorrect treatment prescribed - making the condition worse. Reaching a clear understanding of the root cause of the pain is fundamental in achieving effective rehabiltation.

Pain signals also travel to other parts of the brain including the limbic system where an emotional response to the pain may occur – in some cases this may create feelings of worry, anxiousness, low mood and irritability etc. Signals also travel to the frontal cortex where further evaluation and interpretation of the pain signals takes place. The frontal cortex is the ‘thinking centre’ of the brain and it is here that we develop our thinking responses to pain (It is also the part of the brain where thinking responses to other stressful stimuli e.g. work, environmental, social stress as well as infection occur).

The frontal cortex communicates closely with the limbic system, as well as the hypothalamus in the brain stem which can be thought of as a central controller of various body functions – one important role of the hypothalamus is to assist in blocking pain signals arising from the body. The hypothalamus is influenced by activity in the frontal cortex (what we are thinking), as well as the limbic system (how we are feeling)

As such, how we ‘think’ in the presence of pain can affect how we feel and behave in the presence of pain. Our thinking can also have other physical effects in the body which can lead to acute pain developing into chronic (longstanding) pain.

Why does pain become persistent?

This happens when those parts of the central nervous system responsible for processing pain signals become dysfunctional. Effectively the area of the spine where signals enter via the nerves, as well as the sensory areas in the brain can ‘reconfigure’ so that the sensation of pain becomes persistent – this is referred to as a ‘Pain memory’

This process by which pain memory occurs is called central sensitisation and occurs due to sensory processing errors within the nervous system. One reason for this may be because the ‘load’ on the injured tissues has not been relieved to allow healing. However what is more common is that our ‘thinking’ response may become distorted resulting in inappropriate attitudes and beliefs regarding the nature and cause of the pain.

Examples of unhelpful thoughts include:

• Catastrophising, which can make the problem seem worse than it is or needs to be
• Developing fear avoidance i.e. avoiding activities or tasks out of concern that it may make the problem worse
• Hyper-vigilance i.e. over thinking/analysing the problem, often negatively, so that it almost takes on a life of its own

These unhelpful thoughts result in disturbances in the chemical environment within the limbic system and the hypothalamus (brainstem). This may exacerbate negative feelings sometimes associated with pain. Unhelpful thoughts may also affect the hypothalamus as well as various neural pathways passing between the brain and the rest of the body which disrupt the ability of the nervous system to block pain signals – the result can be the amplification of pain signals as well as a tendency to feel pain in more parts of the body.

How best to treat persistent pain?

An integrated treatment approach using both manual therapy and medical acupuncture can affect how the body processes pain signals and can therefore be very useful in assisting the body to suppress pain. These forms of treatment can be affective in ‘unwinding’ the central sensitivity changes which may have occurred as explained above, however this can take time and patience in the treatment process is often needed.

It is important to note here that the sooner treatment starts the better. By receiving effective and timely pain management treatment you are more likely to recover fully in a shorter time frame and avoid the potential for developing on going, persistent pain. 

Therapeutic exercise, such as Pilates, can also affect how the body processes pain signals and is also helpful in reducing recurrence of pain by improving strength and flexibility. A low impact exercise routine such as Pilates can help prevent injury as well as improve the effectiveness of the rehabilitation process. Exercise also affects the limbic system and often creates a sense of improved well being.

Pain management

Pain is an unpleasant sensory experience and of course there is no point denying that fact. However as explained above, how we think in response to pain can affect the severity of the pain, the level of unpleasantness as well as how long the pain persists. It is helpful to try, as far as possible, to accept the pain as being present then try to challenge and dismiss inappropriate beliefs.

For example:

Try not to think of the cause of the pain as being sinister or severely disabling, most of the time this is not the case. In most cases of persistent pain it is a physiological problem within the nervous system rather than structural problem. If necessary, your Chartered Physiotherapist will refer you for an MRI to rule out any serious underlying problems.

• Try to keep active, doing less of what hurts and more of what makes you feel better
• Pacing is important; break activities up and spread them throughout the day so as not to overdo things
• Consider reassessing how you perform a physical task

Try not to overanalyse the problem and ‘figure it all out’, the more attention that is paid to a problem the more likely it is to persist.

In some cases, a specialist pain management therapist can be a useful member of a combined team approach and may be able to help in dealing with the psychological aspects of pain.

It also helps to maintain a positive focus such as trying to be more aware of the aspects of your rehabilitation that are progressing well, rather than any that may not be.

Specific types of Medication can be a useful adjunct to treatment. Your Chartered Physiotherapist will discuss this with you and your GP.

Summary of main points

Persistent pain is complex and multi-factorial. Regardless of where the pain started, it usually ends up involving the muscles, joints, as well as the nervous system. Treatment often needs to be directed at all of these parts of the body to be successful. This explains why joint injections are often unsuccessful and now not recommended for the treatment of persistent low back pain, for example.

It is possible for an original injury to have healed but for pain still to be present due to the process of central sensitisation.

How you think about the pain will affect its severity and how long it persists.

by Simon.