What is the difference between an epidural and spinal anaesthesia?

Epidural and spinal anaesthesia are called ‘regional anaesthesia’ or ‘regional nerve blocks’. They are used for surgery and also for pain relief in labour. Although they may appear similar, they are in fact quite different. The differences are explained below. 

Modern anaesthesia is generally very safe. Every anaesthetic has a risk of side effects and
complications. Whilst these are usually temporary, some of them may cause long-term problems. 
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Epidural
An epidural is given into your back (outside the spinal cord) by means of a very fine plastic tube
which is inserted through an epidural needle (The needle is removed after the tubing is in place).
Local anaesthetic and other pain relieving drugs are given through the tubing to decrease pain. It
works by blocking the pain signals from reaching your brain. The fine plastic tube is taped onto
your back and drugs can be given through this fine tube for a number of days.
You may have a constant slow infusion or you may have a button to push to give yourself a
dose of the pain relief. This is called Patient Controlled Epidural Analgesia (PCEA).
An epidural may be used on its own for your anaesthetic or combined with a general
anaesthetic.
 
Spinal
A spinal anaesthetic is where a single injection of anaesthetic drugs, is given into the ‘spinal fluid’ of
your back by a very fine needle. It works by blocking the pain signals from reaching your
brain. It also blocks the movement signals which mean that you will be unable to move your legs
while it is working. This type of anaesthesia is quick to work (usually within 5 to 10 minutes) but
only lasts from 1 - 4 hours. You can stay awake or in some cases you can sleep through the surgery by the anaesthetist giving you a sedation or a general anaesthetic as well.
‘A drip’ (IV fluid) is always put into your vein  before the spinal or epidural is done. While you will be pain free during an operation, you may feel strange, pressure sensations around the area of the operation.
 
Potential benefits of an epidural or spinal anaesthetic
• Better pain relief than morphine type drugs
• Less morphine related side effects such as nausea. (if you suffer from morphine type nausea, tell your anaesthetist)
• Less risk of lung complications and infections
• Improved bowel recovery after bowel surgery
• Improved blood flow after vascular surgery
• A quicker return to eating and drinking.
 
Source: Queensland health - https://www.health.qld.gov.au/__data/assets/pdf_file/0030/149853/anaesthetic_04.pdf