What is a spinal anaesthetic?
A spinal anaesthetic is a single injection of local anaesthetic into the fluid around the nerves in your lower back. It numbs your body from about the waist down, so you cannot feel pain and usually cannot move your legs for a while. A small dose of an opioid pain medicine is often added to help with pain relief after surgery.
Spinals are often used for operations on the hips, knees, legs, lower tummy, bladder and prostate, and for caesarean birth.
Before a spinal
- Tell Dr Halvey if you take any medicine that thins the blood, or if you have a bleeding problem. Some of these medicines must be stopped before a spinal can be done safely. See medicines before surgery.
- Tell us about any back problems or back surgery. A spinal is often still possible.
- Fasting rules are the same as for a general anaesthetic. See fasting.
How it is done
- A drip (cannula) is placed in your hand or arm, and monitoring is attached.
- You sit on the edge of the bed leaning forward, or lie on your side curled up. A nurse helps you into position.
- Your back is cleaned with a cold antiseptic, and a small injection of local anaesthetic numbs the skin. This stings briefly.
- A very fine needle is placed between the bones of your lower back. The anaesthetic is injected and the needle is removed. Nothing is left in your back.
If you are having sedation, it is often started before the spinal so you feel relaxed.
What you feel
- While the needle is in, most people feel pressure rather than pain.
- You may feel a brief tingle or electric feeling down one leg. Tell the anaesthetist, but try to keep still.
- Soon afterwards your legs feel warm, then heavy and numb. This is expected.
- The anaesthetist checks the numbness before the operation starts. During the operation you may be aware of movement or pressure, but you should not feel pain.
Awake, sedated or asleep
A spinal can be combined with different levels of awareness, depending on the operation and what you prefer:
- Awake: you are comfortable and can talk with the team. A screen stops you seeing the operation. Some people listen to music.
- Sedation: medicine through the drip makes you relaxed and drowsy. Many people remember little of the operation.
- A general anaesthetic as well: you are fully asleep, and the spinal gives pain relief during and after the operation.
For knee replacement, Dr Halvey usually uses a spinal together with a general anaesthetic, so you are numb and asleep. Sedation instead of a general anaesthetic is possible if you prefer. Your plan is agreed with you before surgery.
As it wears off
Feeling usually comes back first as tingling, then movement returns. How long a spinal lasts depends on the medicine used and the operation, so times vary from person to person.
- Do not try to get up on your own. A nurse will check that your legs are strong enough and help you the first time.
- Start your pain tablets as prescribed, before the spinal fully wears off, so you stay comfortable.
Common after-effects
- Low blood pressure: can make you feel faint or sick. It is watched closely and treated with fluids or medicine.
- Itching: common when an opioid is added. It usually settles and can be treated.
- Difficulty passing urine: your bladder may be slow to work at first. Sometimes a small tube (catheter) is needed to drain it for a short time.
- Shivering: can happen. Warm blankets help.
Headache after a spinal
Occasionally a small leak of fluid from the needle site causes a headache. It is typically worse when you sit or stand and eases when you lie flat. It may not start until the day after the spinal, or later.
If this happens, tell your nurse, or contact the hospital or the rooms if you are at home. Rest, fluids and simple pain relief often help. If it does not settle, a procedure called a blood patch can be offered.
Risks
Serious problems after a spinal are rare. The figures below are from the Royal College of Anaesthetists (UK) patient information, 2025.
| Side effect or risk | How often |
|---|---|
| Low blood pressure needing treatment | Very common, about 10 to 20 in 100 |
| Itching (when an opioid is added) | Very common, about 10 to 15 in 100 |
| Spinal not working well enough, so a general anaesthetic is needed | Common, about 1 in 50 |
| Headache after a spinal | Uncommon, about 1 in 100 to 1 in 200 |
| Nerve damage (numbness or weakness) that gets better | Rare, about 1 in 2,000 |
| Permanent nerve damage | Very rare, about 1 in 20,000 |
| Infection around the spine | Very rare, about 1 in 100,000 |
| Blood clot around the spine | Very rare, about 1 in 100,000 to 1 in 200,000 |
| Paralysis | Very rare, about 1 in 250,000 |
How often words used on this page: very common means more than 1 in 10; common 1 in 10 to 1 in 100; uncommon 1 in 100 to 1 in 1,000; rare 1 in 1,000 to 1 in 10,000; very rare fewer than 1 in 10,000. Figures are averages from published studies. Your own risk depends on your health and is discussed with you.
- numbness or weakness in your legs that is getting worse, or that has not gone when you were told it would
- new back pain, especially with a fever or redness where the needle went in
- problems controlling your bladder or bowels
- a severe headache.