Epidural and spinal
anaesthesia and analgesia
When are epidurals and spinals used?
Epidurals and spinals may be used for many procedures of which the following is a limited selection:
- Caesarean section.
- Lower limb surgery such as hip or knee replacement.
- Hernia repair.
- Varicose vein surgery.
- Vascular surgery of the lower limbs.
- Vaginal repairs and hysterectomy.
- Prostate removal.
- Transurethral resection of bladder tumours.
- Diagnosis and treatment of chronic back pain.
- Pain relief in childbirth.
- Major intrathoracic, intra-abdominal surgery, or lower limb surgery (combined with general anaesthesia).
You’re in good hands
Anaesthetists in Australia are highly trained medical specialists. After graduating from medical school and completing an internship, at least five more years are spent undergoing training in anaesthesia, pain management, resuscitation and the management of medical emergencies.
When you need to have an epidural or spinal anaesthetic, preparation will help to ensure that the experience is a positive one.
The aims of this pamphlet are to:
- Provide you with basic information about epidural and spinal anaesthetics.
- Encourage you to ask questions of your anaesthetist.
- Help you approach the planned procedure positively.
What are epidurals and spinals?
Epidurals and spinals may be used to produce temporary numbness to enable surgical procedures to be performed, and to provide pain relief after an operation or trauma, or for childbirth. Epidurals and spinals are commonly referred to as ’blocks‘ by anaesthetists, meaning that the sensation of pain is ’blocked‘ by the epidural or spinal. Both epidurals and spinals involve the injection of localanaesthetic drugs and/or other medications into the spaces around the spinal cord. The techniques have similarities and differences.
- Spinal anaesthesia is almost always a single injection through a very fine needle into the fluid (cerebrospinal fluid) surrounding the spinal cord. A small dose of local anaesthetic, often combined with other medications, is injected to produce lower body numbness and (if desired) temporary paralysis, lasting 1-6 hours depending on the medications and the doses used.
- Epidurals involve the insertion of a needle into the space outside the spinal cord and spinal fluid (the epidural space). Local anaesthetic, often combined with other medications, may be injected via the needle, or through a small tube (epidural catheter) which may be inserted through the needle. The degree of numbness and temporary paralysis (if desired) depends on the medications injected. The epidural catheter also allows the use of a continuous flow of medications to produce continuous analgesia.
- In some cases, spinal anaesthesia can be combined with an epidural by inserting a long fine needle through the epidural needle and into the spinal fluid before inserting the epidural catheter.
After the epidural and spinal has been
performed
Epidurals take up to 30 minutes to have their maximal effect. The degree of numbness, temporary paralysis and the extent of the epidural ’block‘ is determined by the volume and concentration of local anaesthetic used. The extent of the epidural block is assessed by testing with something cold (like ice) and surgery will not commence until the anaesthetist is happy that the correct degree of anaesthesia has been reached. During surgery, there will
be a screen or drape in front of you so there is no need to worry that you will see the operation. The anaesthesia with an epidural can produce complete numbness which allows surgical procedures to be performed, or it can be adjusted to produce excellent analgesia without complete loss of sensation, with muscle strength maintained. This makes epidural blocks ideal for analgesia in childbirth and for post-operative analgesia.
Spinals have a rapid onset and can produce surgical anaesthesia within 5-10 minutes. Spinals produce a very dense block making it very suitable to be used alone or with minimal sedation. As the spinal takes effect, many patients have a sensation of warmth in their legs or buttocks. This gives way to complete numbness and difficulty moving legs due to temporary paralysis of the nerves supplying the muscles.
