An epidural is a regional anaesthetic which is given through a needle and catheter (a fine tube), into the epidural space by a qualified doctor.

The epidural space, is sometimes referred to as the extradural space, it is situated in the spinal canal before the spinal cord, cerebrospinal fluid and duramater. The epidural space contains soft-tissue and veins.

The purpose of an epidural is to help lower pain sensation, and is most commonly given during childbirth, pre-operatively to be used as a post-operative pain relief and as anaesthesia for Caesarean section.

When an epidural is used to manage chronic back pain, the solution injected is a mixture of analgesics and steroids.

An epidural has to be given by an anaesthetist who will feel for the right space between the vertebrae (which is made easier by positioning the patient suitably), and using a sterile method the anaesthetist will administer a local anaesthetic to numb the skin area before inserting a guidance needle to find the epidural space.

When the space is found, a very fine tube is passed and the drugs are injected. The tube can be left inside which is connected to a machine that will administer the solution at intervals set by the anaesthetist.

An epidural is usually given in the mid-lumbar or lower back as the spinal cord ends at the 1st lumbar vertebra, under which is the cauda equina, (a bundle of nerves that branch off in different directions). The risk of spinal cord injury is lowered when an epidural is given in this way.

Indications of Epidural Use for Back Pain

Epidurals are helpful in managing back pain if caused by herniated discs, degenerative disc diseases or for spinal stenosis. Epidurals have a 50% success rate. In combination with an exercise programme you can achieve results such as lowered irritation to the spinal nerves and a decrease in swelling.

This method is only a temporary pain relief, which can last from one week to a year; it lets the patient use that time taking part in other rehabilitative therapies.
A course of 3 treatments is usually needed but if the first one treatment is totally unsuccessful and no benefit has been gained, there is no reason for carrying on with the remaining treatments.

Effects/Side-Effects of an Epidural

The effects required from an epidural are lowered feelings, lowered pain awareness and loss of muscle power (if required for surgical anaesthesia).

Other side-effects can include a fall in blood pressure, as loss of control of parts of the central nervous system, including that which controls blood pressure and headaches are caused by the epidural. ‘Epidural headaches’ are caused when the cerebrospinal fluid leaks out of its space.

The needle or catheter may be misplaced into a vein; if this occurs it is not very serious but can cause unnecessary distress for the patient. Now and again though, the level of block can be a little higher up the spinal column than expected, patients will need to be closely watched until it has come down to an satisfactory level.

Contraindications/Cautions

• Patients who have bleeding disorders should not be given epidurals, unless adequate time has been given to adjust existing medications.
• Epidurals should not be given through a place of infection or broken or bruised skin.
• There are certain conditions such as spina bifida, scoliosis or previous spinal surgery which may make administration particularly hard so may have to be avoided.

Epidurals can be a very efficient way of controlling chronic back pain. Therefore the benefits can allow patients to try other longer-term therapies to better their chances of being pain free in the future.