We see people everyday saying they are worried they have "done a disc", we thought it was time to talk about whats really happening. There are a number of terms used to describe spinal disc pathology, including "slipped disc", "bulging disc", "disc herniation" or "pinched nerve". But what actually happens?

Discs don't hurt!
-Many herniated discs do not cause pain. In fact current figures show if we scanned 3 people who have no low back pain , one of the three will have a disc bulge. So there is a 33% chance you are sitting there with a disc bulge as you read this and have no pain. Discs are very strong and firmly adhered to your spine above and below, with multiple ligaments anchoring them as well. They are meant to "squish"and "bulge"a bit. There is actually no such thing as "disc pain", but rather the disc contribution to the pain experience.

- Vertebral discs are much stronger than people may think. Given their primary role is in shock absorption, they are able to withstand a great deal of forces placed on the spine during everyday activity. In the case of a disc herniation, material from the centre of the disc bulges out through a tear in the outer surface, occasionally compressing the adjacent nerve root where it emerges from the spinal cord. This is actually quite rare, in our 24 years combined practice we have seen less than "4" patients who had a true "pinched"nerve who required surgery.In fact the spinal nerve only takes up about one third of the space where it comes out of the spine, so there is a lot of room around the nerve.

- Whats a Dorsal Root Ganglion? (DRG). In simple terms it is a cluster of neurons at the back of the spinal nerve. It relays information from your periphery to the spinal cord and brain.  Its an enlarged area and 2 important factors make it a little vulnerable to getting sensitized. First , as you can see in the picture below it is very close to the disc. Secondly and unusually for a nerve, it is poorly myelinated (i.e poorly insulated). When a disc has excessive strain a local inflammatory process occurs. The inflammation in the region can affect the DRG quickly because its close by and poorly insulated. Signals are sent to the brain and the brain can output quite a dramatic pain sensation.

 

-Tissue damage causes a local inflammatory response, where inflammatory cells produce chemicals responsible for mediating the healing process and tissue regeneration. However,these agents also act as irritants,changing the properties of neural tissue surrounding the area of trauma. Changes occur in the brain in response to this repeated nerve stimulation, known as central sensitisation. The brain develops a memory, meaning a more rapid response occurs when the same stimulation occurs in the future. This resulting hypersensitivity means that at times, even though no tissue is being damaged, pain may still be perceived by the individual.

-The level of pain experienced does not always represent the amount of actual tissue damage.

-Where do we come in? Early intervention is the key. Get your Osteopath to make an accurate diagnosis and get the right treatment and advice early on for a quicker recovery. The sooner we settle the local irritation the less likely we are to progress to more central sensitisation as described above.