Sympathetic nerve block

An injection of local anaesthetic around a cluster of 'sympathetic' nerves to see whether quietening them eases certain kinds of long-term nerve pain.

✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review

In short

A sympathetic nerve block is an injection that tries to quieten over-active nerves thought to drive certain long-term pains, such as CRPS.
It is usually temporary and part of a broader pain plan (including physiotherapy and self-management) — not a cure on its own.
Evidence is mixed and benefit varies a lot from person to person; many people get only partial or short-lived relief.
Be cautious if you are offered an open-ended course of repeated blocks with no review, or if it is sold as a guaranteed fix.

A plain-English summary. The detail — including risks and recovery — is below.

At a glance

TypeInjection (nerve block), usually image-guided

AnaestheticLocal anaesthetic to numb the skin; sometimes light sedation

How long it takesAbout 15–30 minutes for the injection itself

Hospital stayOutpatient or day case; usually no overnight stay

Time off workUsually a day or two; you should not drive on the day if sedated

When you'll see resultsAny change in pain is judged over days to a few weeks

On the NHS?Available on the NHS in pain clinics for selected patients; also offered privately

A general guide. Your specialist will give you advice for your situation.

Best fit

May reduce certain types of long-term nerve pain, at least for a time

Pause if

You have an active infection at or near the injection site, or a body-wide infection.

Main recovery point

You stay awake (unless sedated) so you can describe any changes. A neck block often causes a warm face, droopy eyelid and stuffy nose within minutes —...

Good aftercare

A booked review to record how much pain changed and for how long.

During the block

You stay awake (unless sedated) so you can describe any changes. A neck block often causes a warm face, droopy...

First few hours

You are observed in the clinic. Local anaesthetic effects (and any expected neck side effects) wear off. You...

First few days

The injection site may be sore. Any genuine pain relief from the block usually becomes clear over this period...

Days to a few weeks

The team reviews how much your pain changed and for how long. This guides whether to repeat the block, change the...

Medical line illustration of an image-guided needle approaching a treatment target for Sympathetic nerve block. — Illustration only - not a diagnosis, medical advice or a promise of result. Your anatomy and treatment plan may differ. Vuemedics does not publish before-and-after photos.

What is a sympathetic nerve block?

A sympathetic nerve block is an injection of local anaesthetic (sometimes with steroid) placed close to the 'sympathetic' nerves. These nerves run alongside the spine and help control things like blood flow and the body's stress responses. In some long-term pain conditions, such as complex regional pain syndrome (CRPS), these nerves seem to keep the pain switched on.

The two common versions are a stellate ganglion block (at the front of the neck, for pain in the head, face, neck or arm) and a lumbar sympathetic block (in the lower back, for pain in the leg).

A block is mainly a test and a treatment in one. If the injection eases your pain for a while, it suggests these nerves are part of the problem, and the block may be repeated as part of a wider plan that also includes movement, physiotherapy and other treatments. It is usually a temporary measure, not a one-off cure.

The evidence is mixed. Good-quality trials are limited, and a block does not work for everyone. Your clinician should be honest about how likely it is to help you, and for how long.

Types, options & approaches

There may be different ways to do this. The right approach depends on the clinical question and your circumstances.

Stellate ganglion block

Local anaesthetic placed at the front of the neck to target sympathetic nerves serving the head, face, neck and arm. Used mainly for suspected CRPS or other nerve pain of the upper body.

Lumbar sympathetic block

Injection in the lower back targeting sympathetic nerves to the leg, used for suspected sympathetically-maintained pain such as CRPS of the lower limb.

Diagnostic block

A single injection used mainly to see whether quietening these nerves changes your pain, helping decide if further blocks or other treatments are worthwhile.

Therapeutic / repeated block

If a first block clearly helps, a short, reviewed course may be used to create a window for rehabilitation and physiotherapy. Repeated blocks should always be reviewed, not open-ended.

Image guidance

Most blocks are done using X-ray (fluoroscopy) or ultrasound to guide the needle accurately and reduce the risk of hitting nearby structures.

A nerve block versus other approaches

Approach	What it offers	Things to weigh
Sympathetic nerve block	May ease certain nerve pains for a time; helps test the cause	Often temporary; mixed evidence; needles near important structures
Medicines + physiotherapy	First-line for most chronic pain; supported by guidelines	Slower; needs effort and review; side effects from some drugs
Pain-management programme	Builds long-term self-management and function	Does not remove pain directly; takes commitment

A block is usually one part of a plan, not a replacement for rehabilitation and self-management.

Preparing for your procedure

See a pain specialist who explains why a block is being suggested, what it is testing, and how success will be judged.
Tell the team about all your medicines, especially blood thinners (such as warfarin, clopidogrel or apixaban), as these may need adjusting first.
Mention any infection, fever, or skin problems near the injection site, and any allergy to local anaesthetic or contrast dye.
Tell them if you might be pregnant, as X-ray guidance may be used.
Arrange a lift home and someone with you for the rest of the day if you are having sedation.
Keep a simple pain diary before and after, so any change can be judged honestly rather than from memory.
Agree in advance how many blocks will be tried before you both review whether they are worth continuing.

What happens

You lie on an X-ray or ultrasound table and the skin is cleaned and numbed with local anaesthetic. Using the scan pictures to guide the needle, the specialist places local anaesthetic (sometimes with a small dose of steroid) close to the sympathetic nerves. A little contrast dye may be used to check the position.

For a stellate ganglion block in the neck, you may notice a warm, flushed face, a drooping eyelid, a bloodshot eye and a stuffy nose on that side soon afterwards — this is expected and shows the block has reached the right nerves. It wears off over a few hours.

The injection itself usually takes around 15–30 minutes. Afterwards you are watched for a short time, then you can normally go home the same day.

Is this procedure 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…

You have an active infection at or near the injection site, or a body-wide infection.
You take blood-thinning medicines that cannot be safely paused, raising the risk of bleeding near important structures.
Your pain is not thought to involve the sympathetic nerves, so a block is unlikely to help.
You cannot lie still for the procedure or cannot give informed consent.
You have an allergy to local anaesthetic or contrast dye that cannot be managed.

Delay or rearrange if…

You have a current chest or skin infection, fever or feel unwell.
You might be pregnant and X-ray guidance is planned.
Your blood thinners have not yet been adjusted as advised.
Your pain has suddenly changed or there are new neurological symptoms that need assessment first.
You have not yet tried, or been offered, the recommended first-line treatments and rehabilitation.

Alternatives to discuss

Physiotherapy, graded movement and a pain-management programme, especially for CRPS.
Medicines for nerve pain, reviewed for benefit and side effects.
Other targeted treatments such as pulsed radiofrequency in selected cases.
No injection, with a focus on self-management, if the likely benefit is low.
Referral to a specialist CRPS or pain service for a fuller assessment.

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.

Local anaesthetic

The skin and deeper tissues are numbed so the block can be placed while you stay awake and able to report changes.

Light sedation

Sometimes added for anxious patients. It means you should not drive that day and need someone with you afterwards.

Benefits

May reduce certain types of long-term nerve pain, at least for a time
Can help confirm whether the sympathetic nerves are part of your pain
Can create a window of lower pain to make physiotherapy and movement easier
Avoids, or delays, stronger medicines or more invasive treatments in some people
Is usually done as a quick outpatient or day-case injection

Risks & complications

More common

Soreness, bruising or a small lump where the needle went in
Temporary side effects of a neck block (flushing, droopy eyelid, hoarse voice, stuffy nose) that settle within hours
Little or no lasting pain relief — the block may simply not help you
A short-lived increase in pain before any improvement

Less common

Light-headedness or a brief drop in blood pressure
Temporary weakness or numbness beyond the intended area
Difficulty swallowing or a hoarse voice for longer than expected (neck block)
Bleeding or a small collection of blood at the injection site

Rare but serious

Infection at the injection site or, very rarely, deeper infection
Injury to a nerve, blood vessel or, for neck blocks, the lung (a collapsed lung, or pneumothorax)
Seizure or serious reaction if local anaesthetic reaches the bloodstream
An allergic reaction to the injected medicines or contrast dye

The needle passes close to important structures — for a neck block, the windpipe, voice box, blood vessels and the top of the lung; for a back block, the kidney and major vessels. Image guidance lowers but does not remove these risks. Ask how many of these blocks your clinician does, how success will be measured, and what the plan is if the first block does not help.

Published figures to discuss

Reliable numbers for both benefit and harm are limited, because good-quality trials of sympathetic blocks are few and conditions like CRPS vary so much. Reported benefit ranges from useful, temporary relief to no effect at all. Serious complications are uncommon with image guidance but are not zero, so exact percentages should be treated with caution.

Figure	Reported range	How to interpret it	Source / confidence
Temporary low blood pressure, warmth or altered sweating	Common to uncommon depending on block site	Observation after the procedure is used because the sympathetic nervous system affects blood vessels.	Guide sourcesClinical context
Pneumothorax with upper thoracic sympathetic blocks	Rare but recognised	Chest pain or breathlessness after the procedure needs urgent review.	Guide sourcesClinical context
Nerve injury or new neuropathic pain	Rare	Image guidance reduces risk but cannot remove it.	Stellate ganglion intervention for chronic pain: a review (PMC)ncbi.nlm.nih.govSource-linked context
Pain relief being temporary or absent	Common	A sympathetic block may help diagnosis or enable rehabilitation, but it is not a guaranteed cure for CRPS or neuropathic pain.	Guide sourcesClinical context

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 usually no real physical recovery beyond a sore injection site. The main 'recovery' is the wait to see whether, and for how long, your pain changes.

During the block

You stay awake (unless sedated) so you can describe any changes. A neck block often causes a warm face, droopy eyelid and stuffy nose within minutes — this is expected.

First few hours

You are observed in the clinic. Local anaesthetic effects (and any expected neck side effects) wear off. You should not drive on the day if you have had sedation.

First few days

The injection site may be sore. Any genuine pain relief from the block usually becomes clear over this period; keep your pain diary.

Days to a few weeks

The team reviews how much your pain changed and for how long. This guides whether to repeat the block, change the plan, or stop.

What's normal — and not a worry

A sore or slightly bruised injection site for a day or two
Temporary, expected side effects after a neck block (flushing, droopy eyelid, hoarse voice) that settle the same day
Pain that is unchanged, better, or briefly worse before settling
Feeling a little tired or light-headed for the rest of the day, especially after sedation

Aftercare

Rest for the remainder of the day and avoid strenuous activity.
Do not drive, operate machinery or sign important documents on the day if you have had sedation.
Keep the injection site clean and dry for the first day.
Use simple pain relief for injection-site soreness if needed and advised.
Record your pain scores and any change in function over the following days and weeks.
Restart any paused blood-thinning medicine only when your clinician tells you to.
Keep follow-up appointments so the effect of the block can be judged and the plan adjusted.

Before your procedure

Someone to drive you home if you are sedated
A simple pain and activity diary to fill in
List of current medicines, including blood thinners
Agreement on how success will be measured
The clinic's contact number for problems
A plan for what happens if the block does not help

⚠ Get urgent help if…

Difficulty breathing or sudden shortness of breath after a neck block — seek urgent help
Chest pain, a fast heartbeat or feeling faint
A hoarse voice or swallowing difficulty that does not settle within the day
Spreading redness, heat, swelling or discharge at the injection site, or a fever
New or worsening weakness, numbness or loss of bladder or bowel control
Fits (seizures), confusion, a metallic taste or ringing in the ears soon after the injection

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 clear, meaningful drop in your pain that lets you move and function better, even if only for a while. Because effects are often temporary, the aim is usually to use that window for rehabilitation rather than to expect the pain to disappear for good.

A block that gives little or no relief is still useful information: it suggests the sympathetic nerves may not be the main driver of your pain, and that a different approach is needed. It cannot, on its own, prove the exact cause of your pain or guarantee long-term relief.

How long it lasts

Relief from a sympathetic block is often short-lived — sometimes hours or days, sometimes longer — and varies a lot between people. Some gain a useful run of improvement, especially when combined with physiotherapy; others find the effect fades and repeat blocks help less over time. There is no reliable way to promise how long any benefit will last.

Related tests, treatments or support

Blocks are usually combined with physiotherapy, graded movement, pain education and, where appropriate, medicines for nerve pain. For CRPS in particular, the block is meant to support active rehabilitation, not replace it.

Follow-up & long-term care

You should be reviewed after the block to record how much your pain changed and for how long. This review decides whether to repeat the injection, adjust your wider plan, or try something else. Repeated blocks should always be linked to a clear, reviewed goal rather than booked open-endedly.

Repeat, follow-on and what comes next

A block that does not help should prompt a rethink, not automatically more of the same injection.
If a first block helps only briefly, repeat blocks may give less each time and should be reviewed against clear goals.
Sometimes the result is inconclusive and the test simply needs interpreting alongside your wider picture.

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

A booked review to record how much pain changed and for how long.
A clear, written plan linking any further blocks to specific rehabilitation goals.
A named contact and out-of-hours route for problems such as breathing difficulty after a neck block.
Honest discussion about stopping blocks if they are not helping.
Joined-up care with physiotherapy and the wider pain team.

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:

Whether the cost covers the specialist's fee, the procedure room and image guidance (X-ray or ultrasound)
Whether sedation and a sedation-trained team are included
The medicines used (local anaesthetic, steroid, contrast dye)
Whether a follow-up review to judge the result is included
Whether a single block or a planned short course is being quoted
Any imaging or assessment needed beforehand

Make sure your written quote includes

The specialist's fee and who performs the block
The facility fee, including image guidance and any sedation
The medicines and consumables used
A follow-up appointment to review whether it worked
What it costs if further blocks are advised
The cancellation policy
What happens, and what it costs, if a complication occurs

On the NHS? Sympathetic nerve blocks are available on the NHS through pain clinics for selected patients; private access may be used for speed, choice or a second opinion.

You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.

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.

How Vuemedics verifies every consultant →

Questions to ask your medical professional

Take this to your consultation. A good specialist will welcome every one of these.

Why do you think a sympathetic block might help my particular pain?
How will we measure whether it has worked, and over what time?
How many blocks would you try before we review, and what is the plan if it doesn't help?
What are the specific risks for me, given where the injection goes?
How does this fit with my physiotherapy and the rest of my pain plan?
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 procedure, 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 procedure 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

Is a sympathetic nerve block a cure?

No. It is usually a temporary treatment and a test rolled into one. Even when it helps, it is meant to support a wider plan of rehabilitation and self-management, not to remove pain for good.

Will it definitely work?

No. Evidence is mixed and benefit varies widely. Some people get useful relief, others little or none. Your clinician should be honest about your likely chance of benefit and how it will be judged.

Does the injection hurt?

The skin is numbed first. You may feel pressure or a brief sharp sensation as the needle is placed. A neck block often causes a warm, flushed face and droopy eyelid afterwards, which is expected and settles within hours.

How many blocks will I need?

There is no fixed number. Often one is tried first to see if it helps. Any further blocks should be agreed in advance and reviewed against clear goals — be wary of open-ended repeated courses.

Can I have it on the NHS?

Yes, NHS pain clinics offer sympathetic blocks for selected patients, usually as part of a wider pain service. They are also available privately, often with shorter waits.

Can I drive afterwards?

If you have only local anaesthetic and feel well, you may be able to drive later in the day, but if you have sedation you must arrange a lift home and not drive that day.

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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: NICE NG193 — Chronic pain (primary and secondary) in over 16s Faculty of Pain Medicine — Core Standards for Pain Management Services (CSPMS UK 2021) Faculty of Pain Medicine — Standards and guidelines Stellate ganglion intervention for chronic pain: a review (PMC) Ganglion blocks as a treatment of pain: current perspectives (PMC)

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.