What is a sympathetic block?
A sympathetic block is a nerve block procedure using local anaesthetics to interrupt pain signals at various levels in the body. Certain pain conditions send pain signals through small nerve fibres called sympathetic nerves and a sympathetic block may be effective in reducing or eliminating pain. Examples of sympathetic blocks include stellate ganglion, coeliac plexus, lumbar sympathetic and superior hypogastric blocks.
When is a sympathetic block used?
A sympathetic block is used to control pain resulting from:
1. Complex regional pain syndrome
2. Peripheral vascular disease (ischaemic limb pain)
3. Herpes zoster (Shingles)
4. Raynaud’s disease
5. Phantom limb pain
6. Cancer pain
Is the procedure painful?
You will be lying on your stomach during the procedure, except for a stellate ganglion block where you will be lying on your back. The procedure involves insertion of a needle (with the guidance of X-rays) through the skin and the deeper tissues. The skin and deeper tissues will be infiltrated with local anaesthetics to numb the area before inserting the block needle. There will be minimal discomfort during the procedure. Your pain specialist may also administer sedatives or painkillers to you using an intravenous drip to keep you comfortable.
How long does the effect of the medication last?
The local anaesthetic wears off after a few hours. However, the blockade of the sympathetic nerves may last many more hours or even days.
How many injections are needed to treat my pain?
If you respond to the first injection, you pain specialist may recommend repeat injections for you. Usually, a series of injections are needed to treat your pain condition. The response to such injections varies from person to person. In most cases, a series of 3 injections are required.
What should I do after the procedure?
We advise the patients to take it easy for a day or so after the procedure. Perform the activities as tolerated by you.
Can I go back to work the next day?
You should be able to unless the procedure was complicated. Usually you will feel some pain or soreness where the injection needle was inserted.
Will the sympathetic block help me?
It is very difficult to predict if the injection will help you or not. Generally speaking, the patients with a recent onset of pain may respond much better than those with a longstanding pain.
What are the risks and side effects?
Generally speaking, this procedure is safe. However, with any procedure there are risks, side effects, and possibility of complications. The most common side effect is pain - which is temporary. The other risks involve infection, bleeding, nerve damage, worsening of symptoms etc. But these side effects are very uncommon.
Who should not have this injection?
If you are allergic to any of the medications to be injected, if you are on a blood thinning medication (e.g. Warfarin, Plavix, Ticlid), or if you have an active infection going on, you should not have the injection.