Swipe through the images for an introduction to understanding pain!

What is Pain?
Pain is an unpleasant sensory and emotional experience that is associated with, or resembling that associated with, actual or potential tissue damage.

The key messages from the definition of pain:
– Pain always has an emotional component, it is not just a sensory experience
– Pain is associated with tissue damage – not a direct 1:1 relationship!
– The potential for damage is enough to initiate a pain experience

Rather than a direct measure of damage; pain is more closely associated with credible evidence that the body is in danger and needs protecting.

No Brain, No Pain
Pain is an output of the brain, 100% of the time – no exceptions! While danger signals are detected from around the body (nociception), it is the brain that considers these signals and weighs up the threat. If the conclusion is that the body needs to be protected, the brain will produce pain. Presence of danger signals does not necessarily mean there will be a pain response.

The brain considers all available information and makes a best-guess as to whether the body is under threat and needs protecting.

Factors the brain considers in the context of injury:
– Sensory information (what we see, hear, touch etc.)
e.g presence of blood, swelling, physical deformity, crunching/popping/grating sounds

– Social cues (influence of others and our environment)
e.g Uncle Mark hurt his back years ago and he hasn’t been the same, the doctor told me to be careful with my back

– Past experiences
e.g This is similar to the last time I hurt my back and I recovered quickly vs I have never experienced anything like this, I best take care of it

– Beliefs about injury
e.g My back is fragile and needs protecting vs my back is strong and resilient, it will get better!

– Meaning (impact of injury on life)
e.g Will I be able to keep working? Provide for myself and my family? Do the things I love?

If these factors tend to indicate that the injury is something that is likely dangerous to your health and/or future (e.g a fractured bone), then pain is a likely outcome.

However, the brain does not always get this right. Commonly, minor injuries result in horrible pain (e.g paper cut) and significant trauma or life-threatening conditions such as cancers can often present with very little pain and in some cases none at all!

Context & Perception Matter!
The context of a pain experience is critical. A minor finger injury will cause more pain in a professional violinist than in a professional dancer, as it poses a greater threat to the violinist’s livelihood and identity.

Pain is also dependent on the perceived cause of injury. Post-breast surgery, patients who attribute pain to returning cancer have more intense and debilitating pain than those who attribute it to another cause – regardless of what is actually happening in the tissues. This is because pain is more closely related to threat and protection than it is to reporting tissue damage.

Pain ≠ Damage
Nociception (danger detection) is not sufficient or even necessary to cause pain.

Examples:
– A WW2 veteran discovered a bullet lodged in his neck for 60 years following a routine x-ray – he never knew!
– Amputees who experience phantom limb pain in a body part that has been removed
– Chronic pain from an injury that has long since healed

Pain is Complex
Pain is influenced by many factors, including our thoughts, feelings, beliefs and social environment. In fact, every pain experience has an emotional component, such as fear, worry and anxiety which is necessary for survival. Emotion is what gives pain meaning and drives us to change our behaviour – giving pain it’s protective function.

This can help explain why pain in many situations can develop, flare or settle without any obvious physical change in the tissues of the body.

Chronic Pain
For the vast majority of musculoskeletal injuries (where red flags & pathology have been ruled out), adequate tissue healing usually occurs within a 3 month time frame (even for significant injuries such as fractures). Yet pain can hang around despite the tissue having healed nicely – frequently patients are convinced something must be wrong due to the pain, despite imaging showing healthy tissues. In these cases, it is often an overly sensitive nervous system that has become the primary driver of pain rather than the tissues.

The longer pain hangs around, the more efficient the nervous system gets at producing pain (neuroplasticity). In an attempt to protect the body, the brain ramps up the sensitivity of the nervous system. When nerves are sensitised, it takes less input (touch, movement etc.) for danger messages to be sent to the brain – often amplifying pain.

As the nervous system becomes more and more sensitised we often see pain start to spread, become harder to pinpoint and predict. Movements that used to cause slight discomfort become increasingly painful (hyperalgesia), even light touch over the skin can be very tender and sore (allodynia). These changes are driven by the brain trying to protect the body, though we can see this is not helpful considering the tissues themselves are relatively healthy – this is a maladaptive response.

Fortunately, these changes to the nervous system are reversible!

What to Do?!
– Understanding and learning about pain is the first step to taking control of it
– Recognising that pain is complex and not just about the physical aspects – we need to zoom out and take a broader look!
– Taking an active approach to management and relying less on passive strategies (rest, avoiding, pursuing treatments that are done to us)
– Addressing contributing lifestyle factors such as inactivity, stress, sleep and diet
– Recruiting a qualified health professional that understands the complexities of pain to work with you and guide you on the road to recovery

Written by: David Resic (Osteopath)