The term slipped disc is an unhelpful lay term that describes a type of low back or neck injury that may or may not cause pain . It’s important to understand that the spinal discs are not solid structures like a hockey puck and they cannot slip out of place. Neither do the discs trap nerves as we have all heard before. These terms are used to simplify the problem however they can actually create fear and concern in people who have low back pain or who have been told they have a slipped disc.
To understand the pathology we need to understand the anatomy a little better. The spinal disc is divided into two portions. At the centre of the disc is a gelatinous ball bearing called the nucleus pulposus, the nucleus is surrounded by rings of ligament type tissue called the annulus fibrosus. So we have established that the discs do not slip out of place, but you can get a disc bulge. If you have part of the nucleus that has pushed back into the annulus then the annulus can bulge out slightly, sometimes pressing against a nerve root where the nerve passes out of the side of the spinal column.
This slight pressure on the nerve can sometimes cause a little numbness or a pins and needles sensation anywhere down the back of the leg in to the toes or into the shoulder blade, down the arm and into hand if it’s a disc in the neck.
If the disc bulge is quite extensive or what may be called a herniated disc the gelatinous nucleus material seeps out through a split in the annulus and into the spinal canal and spinal foramen where the spinal cord and nerve roots are. This not only creates some mechanical pressure on the nerve roots that can cause muscle weakness and pins and needles but it also irritates the nerves and can create pain.
As there are body fluids (disc material) in a place they are not supposed to be the immune system comes in to the area and starts to clean up the mess, this creates inflammation, which is a normal response, but an inflamed nerve root can be extremely painful and causes a severe and deep pain in the back, buttock and sometimes down the back of the leg or in the neck shoulder and down the arm that may or may not be accompanied by pins and needles.
This type of pain is horrible and patients can be stuck in a very awkward posture, can’t move their neck or bend over, can’t find a comfortable position to sit or lye and find it difficult sleeping at night. But this pain does pass, sometimes after a few weeks and seeing your doctor to get some anti-inflammatory and painkilling medicine will certainly help as well seeing your physiotherapist to get some treatment and exercises.
It’s important to point out that this pain can completely resolve and you can function normally again however with this type of degeneration of the discs in the spine it’s likely you may have stiffness and transient back pain in the future. However you can manage the stiffness and reduce the likelihood of a flare up by adopting a management strategy such as a routine of core stability exercises.
This article was written by Steve Hines of Physiotherapy Wandsworth. Steve is a member of the Chartered Society of Physiotherapists and works in private practice in London.