Nerve block for surgery
An injection of local anaesthetic around the nerves supplying part of the body — such as an arm or leg — to numb it for an operation and to give pain relief afterwards.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- A nerve block numbs part of the body for an operation and gives good pain relief afterwards.
- It can replace a general anaesthetic, or be combined with sedation or a general anaesthetic.
- The limb cannot be used and will not feel pain, heat or knocks until the block wears off, so it needs protecting.
- Modern blocks are very safe; temporary nerve effects are not uncommon and usually settle, while lasting nerve damage is rare.
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.
Good pain relief during and after the operation, often for several hours.
Operations or areas that cannot be reliably numbed by a regional block.
The limb is numb, heavy and cannot be used. You may be given a sling for an arm and need help with everyday tasks.
Clear instructions to start pain relief before the block wears off.
The limb is numb, heavy and cannot be used. You may be given a sling for an arm and need help with everyday tasks.
Start taking your pain-relief medicines so they are working when sensation returns, which can happen suddenly.
You may feel pins and needles as feeling comes back — this is normal. Protect the limb until full sensation and...
The block should have fully worn off. If it has not, contact the anaesthetic department at your hospital.
What is a peripheral nerve block for surgery?
A peripheral nerve block is an injection of local anaesthetic around a nerve, or a group of nerves, that supplies a particular part of the body — for example the arm, hand, leg or foot. It temporarily 'blocks' the nerves, so that part becomes numb and you can have your operation without feeling pain there.
A block can be used instead of a general anaesthetic, which is particularly useful for people whose health makes a general anaesthetic riskier. It can also be combined with sedation or a general anaesthetic, so you have the pain relief of the block while also being relaxed or asleep.
The injection is given with a needle, often using an ultrasound machine so the anaesthetist can see the nerves and place the local anaesthetic accurately. It is not a surgical cut. Most people find the injection no more uncomfortable than having a small tube (cannula) put into a vein.
A major advantage is good pain relief afterwards, which can mean needing less strong pain-relieving medicine. The numbness and pain relief last for a number of hours, and the part of the body involved cannot be used safely until the block wears off.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
Nerve block vs general anaesthetic
| Issue | Nerve block | General anaesthetic |
|---|---|---|
| Awareness | Awake or sedated; limb numb | Fully unconscious |
| Pain relief afterwards | Good, lasts hours | Relies on other medicines |
| Sickness/drowsiness | Often less | More common |
| Main downside | Limb unusable until it wears off | More whole-body after-effects |
A block and a general anaesthetic can also be combined; your anaesthetist will advise what suits you.
Preparing for your treatment
- Follow the fasting instructions you are given — you should usually stop eating and drinking before the operation as advised.
- Tell your anaesthetist about nerve problems, diabetes, or any numbness or weakness you already have in the limb.
- Mention all your medicines, especially blood thinners, as these affect bleeding around the injection.
- Say if you would prefer to be sedated or asleep as well as having the block.
- Arrange help at home, as you will not be able to use the numb limb until the block wears off.
- If it is a day case, arrange a responsible adult to take you home and stay with you, and plan not to drive.
What happens
You will usually go to a room near the operating theatre for the injection. Monitoring is attached and a small tube (cannula) is placed in a vein. Sedation is often given first to help you relax, and if you are having a general anaesthetic too it may be given before or after the block.
The skin is cleaned and a small injection numbs it. The anaesthetist then finds the nerves, usually with an ultrasound machine (which lets them see the nerves, the needle and the local anaesthetic), and places the local anaesthetic around them. Most people find this no more uncomfortable than having a cannula put in.
The limb starts to feel warm, heavy and numb. A full block typically takes about 20–40 minutes to work. If a nerve is touched by the needle you might feel a brief 'pins and needles' or a short pain — tell the anaesthetist if so. Sometimes a block does not work fully, in which case you can have more local anaesthetic, extra pain relief, or a general anaesthetic.
During the operation a screen is used so you do not see it unless you want to, and a member of staff stays with you while the anaesthetist remains close by.
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…
- Operations or areas that cannot be reliably numbed by a regional block.
- Infection over the injection site, or certain bleeding problems and blood-thinner use that make injection near nerves unsafe.
- A genuine allergy to local anaesthetic.
- Inability to cooperate or lie still for the injection, where a general anaesthetic may be safer.
- Pre-existing nerve disease where a block could be unwise — to be discussed with the anaesthetist.
Delay or rearrange if…
- There is active infection over the injection site.
- Blood thinners have not been reviewed and safely managed.
- You have new or unstable symptoms, or are acutely unwell, and the surgery is not urgent.
- Existing numbness or weakness in the limb has not been assessed first.
Alternatives to discuss
- A general anaesthetic instead of a block, where that is safer or preferred.
- Local anaesthetic infiltration for smaller, more superficial procedures.
- A spinal or epidural anaesthetic for some lower-body operations.
- Combining a lighter block with other pain-relief methods.
- Not having the operation, or a non-surgical option where one exists.
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
- Good pain relief during and after the operation, often for several hours.
- May reduce the need for strong pain-relieving medicines that can make you feel sick or unwell.
- Can avoid a general anaesthetic and its risks and after-effects, which can suit people with certain health problems.
- Often allows you to leave hospital sooner.
- Less sickness and drowsiness than a general anaesthetic for many people.
Risks & complications
- A prolonged patch of numbness or tingling in the limb afterwards (about 1 in 10 people), which usually settles.
- Discomfort during the injection, similar to having a cannula put in.
- Bruising where the needle was placed.
- The block sometimes not working fully, needing more local anaesthetic or another option.
- Temporary nerve damage causing numbness, tingling, weakness or odd sensations (fewer than 10 in 100), usually recovering within weeks.
- With injections in the side of the neck: a temporary hoarse voice, droopy eyelid, or some difficulty breathing, which pass as the block wears off.
- Damage to a blood vessel, usually settling with simple pressure.
- With injections near the collarbone: damage to the covering of the lung (less than 1 in 1,000).
- Permanent nerve damage (around 2–5 in 10,000 overall; for a brachial plexus block, long-term nerve damage is estimated at between 1 in 700 and 1 in 5,000).
- Local anaesthetic toxicity if too much medicine reaches the bloodstream (rare), which the team takes care to avoid.
- Very rarely, a fit or another life-threatening event, which the anaesthetist is trained to manage promptly.
Modern nerve blocks are very safe, and serious nerve damage is rare. The figures vary with the type and site of block — for example a brachial plexus block carries an estimated 1 in 700 to 1 in 5,000 risk of long-term nerve damage, and a block lower down the arm may carry less. Remember that nerve problems can also come from the operation itself, the position you lie in, or a tourniquet, not just the block. Ask your anaesthetist about your personal risk and what to do if numbness or weakness lasts more than 48 hours.
Published figures to discuss
Modern nerve blocks are very safe, and the figures below come from RCoA patient information and research studies. They vary with the type and site of block and with your own health, and your anaesthetist will discuss your personal risk. Importantly, some nerve problems after surgery are caused by the operation, positioning or a tourniquet rather than the block.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Prolonged numbness or tingling in the limb | About 1 in 10 people | Resolves in about 95% within four to six weeks and 99% within a year (RCoA). | RCoA — Peripheral nerve blocks (patient leaflet)rcoa.ac.ukPublished figure |
| Temporary nerve damage | Fewer than 10 in 100; most recover in 4–6 weeks, but about 1 in 100 still have symptoms at a year (RCoA) | Usually settles over about three months; minor injuries recover within days to weeks. | RCoA — Peripheral nerve blocks (patient leaflet)rcoa.ac.ukPublished figure |
| Permanent nerve damage (overall) | Around 2–5 in 10,000 (RCoA) | Rare; precise numbers are hard to measure and vary by block type. | RCoA — Peripheral nerve blocks (patient leaflet)rcoa.ac.ukSource-linked context |
| Long-term nerve damage from a brachial plexus (arm) block | Estimated between 1 in 700 and 1 in 5,000 (RCoA) | A block lower down the arm may carry a lower risk. | RCoA — Peripheral nerve blocks (patient leaflet)rcoa.ac.ukPublished figure |
| Damage to the covering of the lung (injection near the collarbone) | Less than 1 in 1,000 (RCoA) | Site-specific; your anaesthetist will discuss this if it applies. | RCoA — Peripheral nerve blocks (patient leaflet)rcoa.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
After the operation the limb stays numb and unusable until the block wears off, commonly several hours. You should start your pain relief before the block wears off, as pain can return quite suddenly.
- A warm, heavy, numb limb while the block lasts.
- Pins and needles as the block wears off.
- Pain returning, sometimes suddenly, as sensation comes back — managed with regular pain relief.
- A small bruise where the injection was given.
Aftercare
- Keep the numb arm in the sling you are given, for support and protection.
- Be very careful around heat sources such as fires, radiators, hobs and hot water — you will not feel heat and burns can happen.
- Avoid using machinery or appliances with the numb limb, as you could injure it without realising.
- Start your pain-relief medicines before the block wears off, as pain can come on quickly.
- Do not rely on the numb limb to bear weight or grip until movement and feeling have fully returned.
- If it is a day case, have a responsible adult with you and do not drive until advised.
- Sling or support ready if it is an arm block
- Pain relief at home, ready to start before the block wears off
- Help arranged for everyday tasks while the limb is numb
- Heat sources and machinery noted as hazards while numb
- Responsible adult and lift home arranged if a day case
- Anaesthetic department contact number saved
Scars and how they heal
A nerve block is given with a needle, not a surgical cut, so it does not leave a scar of its own. You may have a small needle mark or some bruising where it was injected. Any scar comes from the operation itself, not from the block.
⚠ Get urgent help if…
- Unexplained breathlessness after a block in the neck or near the collarbone — seek emergency medical help.
- Severe pain that is not controlled by your pain-relief tablets.
- Numbness, tingling or weakness that lasts more than 48 hours — contact the hospital where you had the operation.
- The block not wearing off by 48–72 hours — call the anaesthetic department.
- Signs of toxicity soon after the injection — ringing in the ears, a metallic taste, numbness around the mouth, dizziness or drowsiness — tell staff at once.
- Spreading redness, heat or discharge at the injection site, or feeling generally very unwell.
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 limb that numbs reliably for the operation and stays comfortable for hours afterwards, often with less need for strong pain relief, and with full feeling and movement returning as the block wears off. Most temporary nerve symptoms settle within weeks.
Blocks do not always work fully, and occasionally more local anaesthetic, extra pain relief, or a general anaesthetic is needed — this is uncommon and easily managed. A block also cannot remove every risk of nerve problems, some of which come from surgery itself.
The numbness and pain relief are temporary, usually lasting several hours and sometimes longer, depending on the local anaesthetic used and whether a tube is left in for ongoing pain relief. It is for the operation and the period afterwards, not a long-term treatment.
Related tests, treatments or support
A nerve block is commonly combined with sedation or a general anaesthetic, and is a core part of enhanced recovery and day-case pathways because it gives good pain relief while reducing strong opioids and the sickness they can cause.
Follow-up & long-term care
Most blocks need no specific follow-up once they have worn off normally. If numbness, tingling or weakness lasts more than 48 hours, or the block has not worn off by 48–72 hours, you should contact the anaesthetic department; they may arrange tests or refer you to a neurologist, and discuss treatment such as physiotherapy if needed.
Repeat, follow-on and what comes next
- If the block does not work fully, more local anaesthetic, extra pain relief, or a general anaesthetic can be given.
- Numbness or weakness lasting more than 48 hours should be reviewed and may need tests or a neurology referral.
- The numbing is temporary and may be repeated for staged procedures.
- Treatment for nerve damage, if it occurs, may include physiotherapy, pain relief or, rarely, surgery.
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
- Clear instructions to start pain relief before the block wears off.
- Advice on protecting the numb limb from heat, knocks and machinery.
- A named contact route, especially if numbness or weakness persists beyond 48 hours.
- A plan to assess and refer if nerve symptoms do not settle.
- Awareness among staff of how to recognise and treat local anaesthetic toxicity.
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 operation itself and whether the block is the main anaesthetic or an add-on for pain relief.
- Whether sedation or a general anaesthetic is combined with the block.
- The anaesthetist's fee and use of ultrasound guidance.
- The clinic, day-unit or theatre facility fee.
- Whether a tube is left in for continuous pain relief afterwards.
- Take-home pain relief and any follow-up.
- The anaesthetist's fee and who will perform the block.
- Whether sedation or a general anaesthetic is included.
- The facility or day-unit fee.
- Whether continuous pain relief (a tube/catheter) is included if relevant.
- Take-home pain relief and follow-up arrangements.
- A contact route for after you go home, and what happens if a complication occurs.
On the NHS? Nerve blocks are a routine part of NHS and private anaesthetic care for suitable operations; private care is mainly about choice and timing rather than a different technique.
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 that the limb must be protected because it cannot feel heat, cold or injury.
- Not mentioning that the block can fail and a general anaesthetic may then be needed.
- Glossing over site-specific risks such as lung-covering damage or a hoarse voice.
- Not giving clear instructions on starting pain relief before the block wears off.
- No advice on what to do if numbness or weakness lasts more than 48 hours.
Marketing red flags
- Describing a nerve block as completely pain-free and without risks.
- Not mentioning nerve damage or local anaesthetic toxicity at all.
- Implying blocks always work first time and never need a general anaesthetic.
- No clear safety net or contact route for problems after discharge.
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 nerve block a good choice for my operation, and would you combine it with sedation or a general anaesthetic?
- What are my particular risks for this block, and how do they compare with a general anaesthetic?
- What happens if the block does not work and I can feel something?
- How long will the numbness and pain relief last, and how should I protect the limb?
- When will my limb feel and move normally again?
- Who do I call if numbness or weakness lasts more than 48 hours?
- 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?
How long will my limb be numb?
What if the block doesn't work properly?
How risky is nerve damage?
Why must I be so careful with the numb limb?
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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 — Peripheral nerve blocks (patient leaflet) RCoA — Nerve damage after a peripheral nerve block (risk leaflet) RCoA — Nerve blocks for surgery on the shoulder, arm or hand (PDF) Local anaesthetic systemic toxicity — review (PubMed) NICE IPG285 — Ultrasound-guided regional nerve block (2009)
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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