Back pain is an extremely common symptom in the general population and incurs great economic and social cost.
About 80-90% of adults in the UK suffer from back pain at some point in their life, the majority will improve over a 3 month period (90%), but unfortunately nearly 50% of those will have a recurrence at some point in the future.
Most back pain is classified as non-specific. This means that the cause of the back pain is not due to any underlying disease process, and generally is due to ‘irritation’ of a number of tissues in the spine (facet joints, intervertebral disc, muscle, ligaments) rather than one distinct specific structure. Pain is generally mechanical in nature in that it is provoked with specific directions of movement / patterns of loading such as bending, leaning, and sitting. Since the nerve tissues which innervate the muscles and skin of the lower limb originate from the low back it is not uncommon for leg symptoms including pain (sciatica), pins and needles, numbness and even muscle weakness to be present.
A slipped disc is more accurately described as a disc bulge. Think of the disc as a jam doughnut. If you constantly put pressure on one side of the doughnut then the jam will start to ooze out the
other side. If you sit all day then the pressure is at the front of the disc pushing the jelly like nucleus pulposus to the back of the disc and creating a bulge. A bulge centrally can put pressure directly on the spinal cord. A bulge which is off to one side causes pain on that side as the bulge irritates the nerves leaving the spine.