Spinal anaesthetic (Spinal anaesthesia (subarachnoid block))
A single injection of local anaesthetic into the fluid around the spinal nerves in your lower back, given by an anaesthetist, that numbs the lower half of your body for an operation while you stay awake.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- A spinal anaesthetic numbs the lower half of your body for an operation while you stay awake, using a single injection in the lower back.
- It is a needle in the back, not a surgical cut, and leaves no scar; numbness usually wears off within a few hours.
- It can mean less sickness and good early pain relief compared with a general anaesthetic for suitable operations.
- Two specific risks to understand are a headache afterwards (treatable) and rare nerve injury; serious harm is uncommon.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your specialist will give you advice for your situation.
Lets you stay awake and avoid a full general anaesthetic for suitable lower-body operations
People taking certain blood thinners or with a bleeding tendency, where a spinal could risk bleeding around the spine, unless this can be safely managed.
Your lower body stays numb and heavy and you cannot move your legs at first. Your blood pressure is monitored. Staff help you stay safe and comfortable...
Monitoring of blood pressure and leg strength until the spinal wears off, with help to avoid falls.
Your lower body stays numb and heavy and you cannot move your legs at first. Your blood pressure is monitored...
Sensation and movement come back gradually, often with tingling. You should not try to stand or walk until staff...
Once you can move and pass urine, and your blood pressure is stable, you can usually eat, drink and (for day...
Any mild backache or bruising at the site settles. Watch for a headache that is worse sitting or standing and...
What is a spinal anaesthetic?
A spinal anaesthetic is an injection of local anaesthetic into the fluid that surrounds the nerves in your lower back. It numbs and temporarily weakens the lower half of your body, so an operation can be done there while you stay awake. It is given and managed by an anaesthetist.
It involves a fine needle placed into your back, low down on the spine, well below where the spinal cord ends. This is not a surgical cut and does not leave a scar. Once the medicine is in, your lower body becomes numb and heavy within minutes, and you usually cannot move your legs until it wears off. Many people choose to stay awake; some have sedation to feel relaxed or drowsy as well.
Spinal anaesthetics are widely used for operations on the lower body, such as hip and knee surgery, some bladder and prostate operations, and caesarean births. For some people they can mean a quicker, clearer recovery than a general anaesthetic, with less sickness and good pain relief afterwards.
Like all anaesthetics, a spinal is very safe but not without risks. The two specific things to understand are a headache that can follow the injection, and rare nerve injury. Your anaesthetist will discuss the risks that matter for you.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
Spinal compared with general anaesthetic
| Spinal anaesthetic | General anaesthetic | |
|---|---|---|
| Awareness | You stay awake (sedation optional) | You are fully asleep |
| What it numbs | Lower half of the body | Whole body and consciousness |
| Sickness | Often less | Sore throat and sickness common |
| Specific risks | Headache afterwards; rare nerve injury | Sore throat; rare awareness, allergy, nerve injury |
| Wears off | Numbness over a few hours | Grogginess over hours |
Not every operation can be done with a spinal. Your anaesthetist will advise which is safest and best for you, and sometimes the two are combined.
Preparing for your treatment
- Attend your pre-operative assessment so your health is checked and the safest anaesthetic is planned.
- Follow the fasting instructions, as a general anaesthetic might still be needed in some situations.
- Tell the team about all your medicines, especially blood thinners or anti-platelet drugs, as these affect whether a spinal is safe.
- Mention back problems, previous spinal surgery, or any difficulty lying or sitting still.
- Mention allergies and any past problems with anaesthetics or local anaesthetic.
- Ask whether you would like sedation as well, and what staying awake will be like.
- Arrange a responsible adult to take you home if you are going home the same day, especially if you have sedation.
- Bring your questions; you will meet your anaesthetist beforehand to discuss the plan and consent.
What happens
Before the operation the anaesthetist reviews your health, explains the plan and answers questions. A cannula is placed in your hand or arm and monitors are attached to track your heart rate, blood pressure and oxygen.
You are usually asked to sit up or curl on your side and to keep still while your back is cleaned. Local anaesthetic is used to numb the skin first, then a fine needle is placed into the lower back to reach the fluid around the nerves. You may feel pushing or a brief tingle, but it should not be sharply painful. The anaesthetic is injected and the needle removed.
Within minutes your lower body feels warm, then heavy and numb, and you will not be able to move your legs. The anaesthetist checks the block is working before surgery starts. Your blood pressure can drop, so this is watched closely and treated if needed. You may have sedation if you have chosen it.
During the operation a screen usually shields your view. You stay awake (or lightly sedated) and feel pressure or movement but not pain. Afterwards, sensation and movement gradually return over a few hours.
Is this treatment right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- People taking certain blood thinners or with a bleeding tendency, where a spinal could risk bleeding around the spine, unless this can be safely managed.
- Active infection at the injection site, or some serious heart conditions, may make a spinal unsuitable.
- Some spine conditions or previous spinal surgery can make the injection difficult or inadvisable.
- Operations that are too long, too extensive, or in the wrong part of the body for a spinal to cover.
Delay or rearrange if…
- You are taking blood-thinning medicine that has not been safely managed around the procedure.
- There is an infection at or near the injection site, or a fever.
- Your blood pressure or fluid balance is unstable.
- Key information, such as a clotting result, is missing.
Alternatives to discuss
- A general anaesthetic, where you are fully asleep.
- An epidural, or a combined spinal-epidural, for longer operations or extended pain relief.
- A regional nerve block for some operations, sometimes with sedation.
- Local anaesthetic alone for smaller procedures.
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Comfort, sedation or contrast choices
If local anaesthetic, sedation, contrast or pain relief is used, ask what is planned, why, and what it means afterwards.
Benefits
- Lets you stay awake and avoid a full general anaesthetic for suitable lower-body operations
- Often causes less sickness and drowsiness than a general anaesthetic
- Gives good pain relief during and for a while after the operation
- Can be a better option for some people with certain heart or lung conditions
- For caesarean birth, lets you be awake to meet your baby
- Quick to take effect and usually wears off the same day
Risks & complications
- A drop in blood pressure causing a feeling of faintness or sickness, which the anaesthetist treats
- Numbness and heaviness in the legs until it wears off
- Temporary difficulty passing urine, sometimes needing a short-term catheter
- Itching or shivering
- Some pushing or discomfort during the injection
- A headache afterwards (post-dural-puncture headache), which can be severe but is treatable
- The spinal not working fully, so a top-up, repeat or a general anaesthetic is needed
- Backache around the injection site for a few days
- Bruising at the injection site
- Temporary nerve damage causing numbness, tingling or weakness in a leg, usually recovering over days to weeks
- Permanent nerve damage, which is very rare
- Infection or bleeding around the spine (such as an abscess or blood clot pressing on nerves), which is very rare but serious
- A severe allergic reaction to the medicines
- Very rarely, the block spreading too high and affecting breathing or blood pressure, which the anaesthetist manages
The two risks people most want to understand are the headache that can follow a spinal and the rare risk of nerve injury. The headache is treatable, often with simple measures and, if needed, a procedure called a blood patch. Serious nerve injury is very rare. Tell your anaesthetist about any blood thinners, back problems or bleeding tendencies, and report any severe headache, worsening leg weakness, numbness around the back passage or loss of bladder or bowel control straight away.
Published figures to discuss
Most effects of a spinal are common but minor and short-lived; the serious risks are rare. The Royal College of Anaesthetists publishes cautious figures and notes that risk varies with your health, the operation and the technique. Headache rates depend a lot on the needle used and the patient, and permanent nerve injury is very rare. The figures below are drawn cautiously from RCoA patient information and should be treated as approximate.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Headache after the spinal (post-dural-puncture headache) | Uncommon with modern fine needles — broadly in the region of around 1 in 100 to 1 in 200, varying by needle and patient | Treatable; often settles with simple measures, and a blood patch is highly effective if needed. | RCoA — Headache after a spinal or epidural anaestheticrcoa.ac.ukPublished figure |
| Low blood pressure during the spinal | Common | Expected and routinely treated by the anaesthetist with fluids and medicine. | Guide sourcesClinical context |
| Permanent nerve damage | Very rare — RCoA patient materials describe figures around 1 in 50,000 or rarer | Temporary nerve symptoms are commoner and usually recover; permanent harm is very unusual. | RCoA — Your spinal anaestheticrcoa.ac.ukPublished figure |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
What happens afterwards
There is no surgical wound from a spinal, just a tiny needle site. The main thing afterwards is waiting for the numbness and leg heaviness to wear off, which usually takes a few hours, and watching for the specific warning signs.
- Numb, heavy legs that you cannot move at first
- Tingling as feeling returns
- A short period of difficulty passing urine
- Mild backache or a small bruise at the injection site
- Feeling faint or slightly sick if your blood pressure dips, which is treated
Aftercare
- Do not try to stand or walk until staff confirm your leg strength and sensation have returned.
- Tell staff if you cannot pass urine, as you may need a short-term catheter.
- Drink normally and rest as feeling returns.
- If you had sedation, do not drive, drink alcohol or be alone for at least 24 hours.
- Take simple pain relief and keep well hydrated, which can help if a headache develops.
- Report a headache that is worse when upright and better lying down.
- Seek urgent help for worsening leg weakness, numbness around the back passage, or loss of bladder or bowel control.
- Follow the aftercare for the operation itself.
- Staff confirmation that your legs are safe before you stand
- A responsible adult to take you home if you had sedation
- Simple pain relief and fluids at home
- Knowing the headache warning sign and what to do
- Knowing the urgent nerve warning signs
- The ward or clinic contact number saved
- Aftercare instructions for the operation itself
Scars and how they heal
A spinal is given through a fine needle, not a surgical cut, so there is no scar. You may have a tiny puncture mark or a small bruise on your back that fades within days.
⚠ Get urgent help if…
- Worsening weakness or numbness in your legs after the spinal should have worn off — seek urgent help
- Numbness around the back passage or genitals, or loss of bladder or bowel control — seek urgent help
- A severe headache that is worse when sitting or standing and better lying down
- Increasing back pain with fever, or redness and discharge at the injection site (possible infection)
- Difficulty breathing, or swelling of the face, lips or tongue (possible allergic reaction) — call 999
- Being unable to pass urine despite a full bladder
- Any warning sign related to your operation
Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your specialist gives you.
Results & realistic expectations
A good result is a spinal that works fully, so the operation is comfortable, and that wears off cleanly with no lasting effects. Many people value being awake, having less sickness and getting good early pain relief.
A spinal enables the operation but does not change its result; how you do overall depends on the surgery and your recovery. Occasionally a spinal does not work fully and needs topping up, repeating, or converting to a general anaesthetic, which your anaesthetist will discuss as a possibility beforehand.
A spinal anaesthetic is short-acting and wears off within a few hours, leaving no lasting effect for almost everyone. A headache, if it happens, usually settles within days, sometimes with treatment. Serious longer-term effects, such as permanent nerve injury, are very rare.
Related tests, treatments or support
A spinal is sometimes combined with sedation so you feel relaxed, or with an epidural (combined spinal-epidural) so pain relief can be topped up for longer operations or afterwards. Occasionally it is used with a general anaesthetic, mainly for pain relief. Your anaesthetist will explain any combined plan.
Follow-up & long-term care
Most people need no specific follow-up for a spinal, as it wears off quickly. If you develop a headache or any nerve symptoms, these should be reviewed: while in hospital by the anaesthetic team, and after discharge by contacting the team or your GP. Severe or persisting symptoms need prompt assessment.
Repeat, follow-on and what comes next
- A spinal sometimes does not work fully and may need topping up, repeating, or converting to a general anaesthetic.
- If a headache develops, it may need review and sometimes a blood patch.
- Any nerve symptoms should be assessed, and most settle without further treatment.
Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.
What good aftercare looks like
- Monitoring of blood pressure and leg strength until the spinal wears off, with help to avoid falls.
- Checking you can pass urine before discharge, and managing this if not.
- Clear written warning signs for headache and for serious nerve symptoms.
- A named contact and prompt review if a headache or nerve symptoms develop.
- Joined-up care between the anaesthetic team and your GP after discharge.
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- The anaesthetist's fee, reflecting the length and complexity of the operation
- Whether sedation or a combined spinal-epidural is used
- Monitoring needed during and after the spinal
- Your overall health, which can affect the anaesthetic plan
- Recovery time and any additional pain-relief arrangements
- Whether the anaesthetist's fee is included in your overall surgical package or charged separately
- Who your anaesthetist will be and how to contact them with questions
- Whether sedation and monitoring are included
- Whether pain relief and recovery care are included
- What happens, clinically and financially, if the spinal needs converting to a general anaesthetic
On the NHS? A spinal anaesthetic is standard NHS care for many lower-body operations and is also used in private surgery; it forms part of the cost of the operation rather than a separate self-pay treatment.
You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- Not explaining the headache and rare nerve-injury risks specific to spinals.
- Describing it as a simple jab without mentioning it can fail and need a general anaesthetic.
- Not asking about blood thinners, back problems or bleeding tendencies.
- Not giving clear urgent warning signs, such as worsening leg weakness or loss of bladder control.
- Confusing a needle in the back with a surgical procedure that leaves a scar.
Marketing red flags
- Promising a spinal will definitely work and never need a general anaesthetic.
- Calling it risk-free or without risks rather than very safe but not without risk.
- Skipping discussion of the headache and nerve risks.
- Not explaining who manages your blood pressure and recovery.
Choosing a specialist safely
- Check the specialist is on the GMC Specialist Register for this area.
- Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
- You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
- Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including any follow-up — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good specialist will welcome every one of these.
- Is a spinal suitable for my operation, and why is it being recommended for me?
- Would I have sedation as well, and what will being awake be like?
- What are my particular risks, including of headache or nerve problems?
- What happens if the spinal does not work fully during the operation?
- How will my blood pressure and bladder be looked after afterwards?
- What symptoms after the spinal should make me seek urgent help?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the specialist who carries out my treatment, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this treatment not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
Will I be awake during the operation?
Does the injection hurt?
What is the headache I have heard about?
Can a spinal damage my nerves or paralyse me?
When will I be able to walk again?
What if the spinal does not work fully?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: RCoA — Your spinal anaesthetic RCoA — Headache after a spinal or epidural anaesthetic RCoA — Nerve damage after a spinal or epidural anaesthetic RCoA — Spinal anaesthetics: risks and side effects NHS — Anaesthesia
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
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