Back Pain in Adults
Lower back pain is extremely common, about 80% of people have one or more episodes of back pain during their life. Stiffness and pain in the low back are the main symptoms. Even though in most cases the precise cause of the back pain is not clear, the vast majority of back pain episodes are not due to anything serious wrong with the back, such as cancer or other important diseases.
Chronic back pain is much less frequent than acute back pain but there are still many sufferers with it being the second most frequent reason for long term disability next to arthritis. It is also a leading cause of work loss.
Overall levels of reported low back pain have doubled in the last forty years and the explanation for this is not clear, but it might be because people are more likely to report cases of back pain to their doctor or that people are becoming more stressed, depressed, obese and unfit with time. These factors are all known to have relevance to back pain occurrence.
Current advice is to maintain as normal a level of physical activity as you can without suffering too much pain, take painkillers and wait until the pain settles down. Returning to fully normal activity is encouraged as soon as possible but it is quite likely that the pain episode will recur at times. A small number of people develop long term or chronic back pain, which may need management by an orthopaedic surgeon or a pain clinic.
Understanding Your Lower Back
The low back region consists of the lumbar vertebrae (spinal bones) and the sacrum which is the large triangular bone at the bottom which connects at each side with the pelvis. The whole area is referred to as the lumbosacral spine.
There are five lumbar vertebrae sitting on top of each other to form the lumbar spine. These are an inch or more high each and roughly of a circular shape, with a disc in between each one. Discs have a tough, more fibrous outer layer (annulus) and a softer centre which behaves like a gel (nucleus). The discs allow movement of the spine and larger discs are present in areas of greater movement in the spine. They also absorb loads and transmit them equally to the bones above and below. Discs are extremely strong and rarely fail unless they have had trauma and time to change – doctors call this disc degeneration.
The discs are tightly bound to the vertebrae above and below and are unable to “slip out” so a slipped disc refers to a disc protrusion of the gel through the outer layers. Strong ligaments support the spine by attaching from one bone to another up and down the whole spinal column.
A large number of strong muscles attach to the spine and act as movers or stabilisers when we want to complete activities. At the back of the spine is the spinal canal, a bony tube where the spinal cord sits as it runs down from the brain to allow the nerves to reach all parts of the body.
As changes may occur asymmetrically in the low back you can suffer from right back pain or left back pain and the back pain cause may be clearer in these cases than with generalised backache.
Back Pain Types
Back pain can be caused by a large number of different conditions, some related to the structure of the low back and some related to other diseases and illnesses.
Non-specific Low Back Pain
This is the name given to the commonest type of lower back pain and around 80% of all episodes are diagnosed as “non-specific” which means that no structure can be identified as the cause with any certainty. This type of back pain can be mild or extremely severe and troublesome but is not serious from a medical point of view, i.e. there is no serious condition underlying it.
Specific Back Pain Problems
Slipped Disc or Prolapsed Disc
Disc problems are common and may vary from a tear in the outer covering due to a twist and lift through to a split in the outer disc wall where the gel inside the disc bulges out. The outer disc walls are sensitive to pain from injury and overstress.
Nerve Root Pain – Sciatica
Much less common than back pain, it occurs in around five percent of cases and is distinguished from back pain by being very severe, surging pain down the leg, often worse in the foot than further up. The pain is usually in a typical pattern related to which nerve is involved. In some cases there may be no back pain at all.
Sciatica is mostly caused by nerve compression and irritation from by a disc prolapse, as the gel nucleus of the disc protrudes through the outer wall and hits what is called the nerve root, the part of the nerve which has just come off the spinal cord and is on its way down to the leg. This is often referred to as a trapped nerve.
Irritation and compression of the nerve root gives the severe pain in the leg and also can give loss of reflexes on testing, loss of muscle power in the muscles it supplies, pins and needles and numbness.
Most leg pain is not sciatica but referred pain from the structures in the spine, where the brain interprets the messages coming in from the spine as being in the buttock, hips or legs. This kind of pain rarely goes below the knee and is more achey and hard to pin down, rather than the sharp, very unpleasant and clearly defined pain of sciatica.
Cauda Equina Syndrome CES – A Rare but Serious Condition
Cauda equina syndrome a very serious type of nerve compression where the nerve in the lowest part of the spinal canal are compressed severely, either by a huge disc prolapse, trauma such as a fracture, or a tumour.
Symptoms of CES include severe and disabling back pain, variable leg weakness or pain, interference in bladder or bowel function and loss of feeling between the legs around the genitals and anus. This is an extremely serious condition if it occurs and you should consult a doctor at once if you have this combination of symptoms, or you may risk long term problems.
Other Back Pain Causes
Osteoarthritis, the commonest degenerative joint condition in the world, can affect the posterior spinal joints and become painful. This is more common in older people.
Ankylosing spondylitis (AS) is an arthritic disease most commonly presenting in young men, where the inflammation and pain leads to increasing joint stiffness over time. AS needs management by a rheumatologist.
Rheumatoid arthritis, another arthritic disease, can have serious spinal effects along with the more obvious effects on the limb joints. Rheumatological management is important here too.
Tumours, infections, trauma, osteoporosis and other conditions may also cause low back pain and are referred to as non-mechanical low back pain. These problems all need specialist assessment and treatment. These occur in less than 1% of cases of low back pain and are more common again in older people.