Dr Mark Miller FRCA
Consultant Anaesthetics and Pain Management
Royal Shrewsbury Hospital and Shropshire Nuffield Hospital.
Born 1965, Edinburgh. Qualified 1990 MBChB Manchester University. Acquired membership of the Royal College of Anaesthetists in 1997.

LOW BACK PAIN

Back pain is assessed in the pain clinic to exclude serious and life-threatening causes such as tumours and aortic aneurysms. Back pain may also be felt secondary to a more significant pain in another area. The pain clinic will refer you to the appropriate doctor/surgeon if such a condition is found.

When the pain is primarily from the back then it may be either confined to that area or associated with pain in the legs, groin or abdomen or even further up the back even as far as the neck, shoulders and head. This latter pain is called referred pain

Simple low back pain. This is pain felt in the back alone. It is important to treat this early and effectively and exclude sinister causes as mentioned above. Bed rest and immobility are not recommended for more than 2 to 3 days. Continuation of a normal life style using regular over-the-counter painkillers and careful goal-targeted exercises suffice for the majority. If this is insufficient then your G.P. can refer you to a physiotherapist and prescribe stronger pain killers such as codeine-containing drugs.

Patients with low back pain with referred symptoms may have prolapsed discs compressing nerves, ligament damage, inflammation in the joints between the bones of the vertebral bodies (facet joints), arthritis or degeneration in the same bones with resulting nerve compression. This nerve compression results in sciatica, that is shooting pains in the legs.

The majority of patients with low back pain who come to the pain clinic are many weeks down the road from its onset. Sinister causes still have to be ruled out. Often they will have seen other Consultants and have had investigations such as MRI scans and X-rays. Treatment in all cases follows the lines as mentioned above i.e. pharmacological, physical and psychological.

Physical treatments
Ligament Sclerosant

It may be felt that your main problem is laxity in the ligaments in the lower back.

Ligaments go from bone to bone and act as stabilisers. The main ligament to become damaged is the ilio-lumbar ligament which connects the lowest two lumbar vertebrae to the pelvis. It may be damaged by degenerative changes in the vertebral column itself or following external trauma. The attachments to bone may be weakened and stretched.

Injection treatment with sclerosant solution (a phenol, glycerol, glucose combination) at these damaged edges causes scarring and strengthening of the ligament once more and can relieve pain.

A series of these injections can be undertaken if the response to the first one is positive. Pain relief can be life-long but more often than not further injections are required in the future. Very rarely the injections may make no difference or even may cause a worstening of pain.

A test injection of local anaesthetic and steroid alone can be predictive of a positive response. Other rare side-effects include infection (1 in 17000 risk) and damage to the ureter (urine-carrying tube) so an X-ray machine is used to reduce this risk.

Other pelvic ligaments can also cause pain.
The posterior sacro-iliac ligament can irritate a muscle called the pyriformis muscle and this can lead to sciatica-like symptoms in the absence of a slipped disc. Sclerosant therapy can be used here as well.

Facet Joint Injections

Your symptoms and signs may suggest that the facet joints (the joints between the vertebral bodies) are the source of your pain.

Sitting, stretching backwards and turning to the side are often painful here. These joints can be injected with very small doses of steroid and a positive response (pain relief for weeks/months) can be followed up with an injection therapy known as rhizolysis where the nerves that supply the joints are destroyed with radiofrequency waves which cause local heating hopefully giving a long period of pain relief. These nerves can regenerate so causing a return of the pain some months/years later but the procedure can be repeated if necessary.

Epidural with local anaesthetic and steroid Slipped discs will often give rise to both local and referred symptoms. Most commonly it occurs in the lumbar spine and gives rise to aching or shooting pains in one or both legs.

Slipped discs also occur less commonly in the neck with associated arm pain and even less commonly in the thoracic vertebral area with associated chest or groin pains. Similar symptoms may arise if a spondylolisthesis occurs.

This grand sounding term describes the slippage of one vertebra on another. This can lead to narrowing of the space available for the spinal cord and the nerve roots. Narrowing of the spinal space is called spinal stenosis. MRI scans are excellent diagnostic tools in this area.

If spinal stenosis leads to excessive interference with peripheral sensation or power or interferes with bowel or bladder function, then an operation is necessary.

Where spinal stenosis is causing symptoms but no operation is deemed necessary then performing an epidural with depot steroid can help the peripheral symptoms. The depot steroid can reduce the symptoms due to inflammation and nerve compression.

As a rule of thumb, with slipped discs, the shorter the time of symptoms then the greater the chance of prolonged pain relief. Steroids are not licenced to go in the epidural space but the procedure has been performed for many years with the benefits outweighing the risks for most people. The main risks are infection, blood clot formation with nerve compression and inadvertent spinal tap. I perform epidurals using an x-ray machine to make sure the needle is in the right place and to minimise the risk of spinal tap.

Other aspects to management of back pain