Epidural - Indications

Indications

Injecting medication into the epidural space is primarily performed for analgesia. This may be performed using a number of different techniques and for a variety of reasons. Additionally, some of the side-effects of epidural analgesia may be beneficial in some circumstances (e.g., vasodilation may be beneficial if the subject has peripheral vascular disease). When a catheter is placed into the epidural space (see below) a continuous infusion can be maintained for several days, if needed. Epidural analgesia may be used:

• For analgesia alone, where surgery is not contemplated. An epidural injection or infusion for pain relief (e.g. in childbirth) is less likely to cause loss of muscle power, but is not usually sufficient for surgery.
• As an adjunct to general anaesthesia. The anaesthetist may use epidural analgesia in addition to general anaesthesia. This may reduce the subject's requirement for opioid analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. hysterectomy), orthopaedic surgery (e.g. hip replacement), general surgery (e.g. laparotomy) and vascular surgery (e.g. open aortic aneurysm repair).
• As a sole technique for surgical anaesthesia. Some operations, most frequently Caesarean section, may be performed using an epidural anaesthetic as the sole technique. Typically the subject would remain awake during the operation. The dose required for anaesthesia is much higher than that required for analgesia.
• For post-operative analgesia, after an operation where the epidural technique was used as either the sole anaesthetic, or was used in combination with general anaesthesia. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a patient-controlled epidural analgesia (PCEA) infusion pump, a person has the ability to give himself an occasional dose of pain medication through an epidural catheter.
• For the treatment of back pain. Injection of analgesics and steroids into the epidural space may improve some forms of back pain. See below.
• For the treatment of chronic pain or palliation of symptoms in terminal care, usually in the short- or medium-term.

The epidural space is more difficult and risky to access as one ascends the spine, so epidural techniques are most suitable for analgesia for the chest, abdomen, pelvis or legs. They are (usually) much less suitable for analgesia for the neck, or arms and are not possible for the head (since sensory innervation for the head arises directly from the brain via cranial nerves rather than from the spinal cord via the epidural space.)