Okay, let’s move on. Another common injury that is reported is a ‘slipped disc’ or a ‘herniated disc’. But what does this represent with regards to back pain? The intervertebral discs are located between each of your spinal bones and provide protection, range of motion and shock absorption. A herniation/bulge/slipped disc is where a portion of the disc begins to push out from its typical anatomical position. Alongside this, patients typically fall into the train of thought that the disc will never heal, and they will have back pain long term. However, this isn’t entirely true as research shows that over the course of 2 years, up to 80% of disc herniation can reabsorb and recover with conservative management comprising of mobility and strengthening exercise, self-management and advice on suitable physical activity.
The intervertebral discs are common analogised as tyres in the health profession, they’re like a thick rubber and just like normal road tyres, over the course of time they are subject to wear and tear which is NORMAL and expected as we age! With these so-called ‘slipped discs’ or ‘herniations’ is that – as the NORMAL wear and tear takes place, the discs lose some of their structural integrity and can be likened to a slightly flattened tyre. What this leads to is a form of folding or crimping like you see in a flat tyre and this is what can be attributed to nerve irritation which may lead to symptoms being experienced in the buttock and down the leg which is commonly referred to as sciatica.
Sciatica is an umbrella term which relates to conditions that involve irritation of the nerves that supply the lower limbs at their source – the lower back. All our limbs are supplied by a vast nerve network which sends electrical impulses to our extremities so that we can feel, move, rip, grip, push, pull etc. These nerves stem back to the spinal cord which is in the middle of our spine and is an extension of the brain and forms our central nervous system. To be able to reach our limbs, the nerves branch out of the spine in gaps between each vertebrae – these gaps are called foramen. Approximately one third of the space at each foramen is taken up by the nerve roots, leaving plenty of space to mobilise and not be irritated.
However, what can happen when the inter-vertebral discs begin to wear (like a flat tyre), they can push into these holes where the nerves come out and increase pressure which can lead to nerve irritation and pain. What we know is that with time, discs can progressively heal and re-absorb, and the optimal management of these issues is to mobilise, strengthen and stretch!! This is what the lay person would commonly describe as a ‘trapped nerve’. Stop. A trapped nerve is vastly different and would be associated with a total switch off and numbness of a limb or region of a limb and is an event which requires immediate investigation.
Although this pathology may be present, it doesn’t typically represent the sole cause of back pain. Research has highlighted that pathology has a poor link to pain and that our beliefs & apprehension regarding back discomfort tend to be more significant drivers in back pain experience. Remember, pain is a complex and multi-factorial experience… A great analogy for this is listening to an orchestra, there’s lots of different noises all happening at once and learning to listen to just one ‘instrument’ or driver in our experience of pain can be very complicated. This again is where Physiotherapists can provide their expert knowledge and experience to differentiate the key factors contributing to your symptoms.