One block tells you whether the sympathetic system is driving this.

STELLATE GANGLION BLOCK

A cluster of sympathetic nerves at the base of the neck supplies the head and arm. Anesthetising it tells you whether the sympathetic system is driving your pain — and in the right patient, interrupts it.

What the stellate ganglion is

A collection of sympathetic nerve cell bodies sitting in front of the neck vertebrae at roughly C6-C7, formed where the inferior cervical and first thoracic ganglia fuse. It supplies sympathetic outflow to the head, neck and upper limb — blood vessel tone, sweating, and part of the pain signalling that becomes disordered in CRPS.

Blocking it with local anesthetic switches that outflow off temporarily on one side. If the pain is being maintained sympathetically, it falls away during that window.

What it is used for here

• Upper-limb CRPS — the main indication, both to test whether the pain is sympathetically maintained and to open a window for rehabilitation.
• Refractory neuropathic arm and hand pain where a sympathetic component is suspected.
• Vascular insufficiency in the hand in selected cases.
• Persistent post-surgical upper-limb pain with vasomotor features.

It is diagnostic and therapeutic in the same appointment, which is unusual and useful: a block that changes nothing has told you the sympathetic system is not the driver, and that redirects the whole plan.

How honest the evidence is

Systematic review of stellate ganglion block for CRPS supports meaningful short-term pain reduction. The same review, and the broader Cochrane assessment of CRPS interventions, are clear that study quality is limited and effects are not uniformly durable.

So the defensible claim is this: it reliably answers a diagnostic question, it frequently produces useful short-to-medium-term relief, and it is a means of enabling rehabilitation rather than a cure. A practice promising more than that is going beyond what the literature carries.

What the procedure involves

• Lying supine with the neck slightly extended. Ultrasound guidance throughout — this area contains the carotid, the vertebral artery, the thyroid and the recurrent laryngeal nerve, and it is not a landmark procedure.
• A small volume of local anesthetic placed in front of the longus colli muscle.
• Under ten minutes. Awake, because your report during the block is part of the point.
• You are observed afterward and you do not drive yourself home from this one.

The expected side effects, which look alarming and are not

A successful block produces Horner’s syndrome on that side — a drooping eyelid, a constricted pupil, a bloodshot eye, and a warm, dry, flushed face and hand. That is confirmation the block worked, not a complication, and it wears off with the anesthetic over some hours.

Hoarseness and a sensation of a lump in the throat are common from spread to the recurrent laryngeal nerve. It is temporary. You should not eat or drink until swallowing feels entirely normal.

Serious complications are uncommon and are the reason the procedure is done under imaging with small volumes and aspiration: intravascular injection, particularly into the vertebral artery, is the one that matters and is what the technique is designed to avoid.

How we read the result

Substantial relief during the block points at a sympathetically maintained component and justifies a short series alongside intensive rehabilitation. Relief that outlasts the anesthetic by days or weeks is a good prognostic sign.

No change is a genuinely useful negative and we will say so rather than repeating it hopefully. Sympathetically independent pain is common in CRPS and needs a different plan — which may include neuromodulation.

What to arrange before you come

Do not eat for a few hours beforehand, bring somebody to drive you, and allow the afternoon. Take your usual medications unless told otherwise, and tell us in advance about anticoagulants, because that changes the plan rather than canceling it.

Bring the affected limb uncovered to the appointment — short sleeves. Photographs of the limb at its worst are genuinely useful if the color and swelling fluctuate, which they usually do.

The window is the point

The relief from a single block is measured in hours to days. That is not the treatment; it is the opportunity. The hours after a successful block are when the limb can be moved, desensitized and used in ways that are impossible the rest of the time.

Which means the block should be scheduled around therapy rather than in isolation. A block given on a Friday with nothing arranged until the following week has wasted most of what it bought.

If the first block works, what follows

A short series alongside intensive therapy, spaced so each block lands on a day when the limb can actually be worked. Three to six is typical, and the decision to continue is made on function regained rather than on hours of relief reported.

Where relief is real but the series plateaus, the options are a longer-acting approach or moving to neuromodulation if the condition is genuinely refractory. Where it never worked at all, we stop rather than persist, and the diagnosis gets revisited.

What people ask about stellate blocks

Will my eyelid stay droopy?

No. Horner’s syndrome after a stellate block is temporary and wears off with the anesthetic over a few hours. Its appearance is how we know the block reached the target. CRPS, and what the diagnosis means.

How many will I need?

If the first one helps, a short series alongside rehabilitation is usual. If it does not help at all, repeating it is not the answer and we will look elsewhere. Where spinal cord stimulation fits.

Is it dangerous?

The anatomy is significant and that is precisely why it is done under ultrasound with small volumes. Serious complications are uncommon; temporary hoarseness and Horner’s are expected rather than adverse. What hand symptoms localize to.

Can I eat afterward?

Not until swallowing feels completely normal, because the nerve to the voice box is often partially affected. That is usually a few hours. CRPS, and what the diagnosis means.

Related reading

• Complex regional pain syndrome
• Dorsal column stimulation
• When your hands are the problem
• Cervical radiculopathy
• EMG and nerve conduction studies
• What happens at the first visit