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Lumbar Chemical Sympathectomy

As well as the main nervous system supplying our bodies, there is a second system called the autonomic nervous system, which is mainly responsible for controlling the functions of our internal organs. Part of this autonomic nervous system is the sympathetic nervous system. Amongst other functions, nerve fibres from this system travel into our limbs and carry the nerve impulses which control the diameter of blood vessels in the arm, head and face and sometimes activity in these nerves can be involved in certain types of nerve pain, or pain signals can be carried in their pathways. The sympathetic nerves travel in a chain of nerves that run down the sides of the vertebrae in the back. Sometimes, most commonly to try to improve the blood supply through the very small arteries in the legs or occasionally to help in the management of other pains, blockade of the nerves in this chain can be done. This may be either with local anaesthetic or with chemicals such as phenol to more permanently stop the function of the nerves. The latter is called a Chemical (or Neurolytic) Sympathectomy.

Where is the injection carried out?

You will be asked to attend the Day Surgery Unit for half a day (morning or afternoon) On the day you will be greeted by a nurse who will look after you until you go home. You may be asked to change into a gown and will be taken to one of the operating theatres for the procedure.

How is the injection done?

You will be asked to lie on your front or side on a special table that allows us to use an X Ray machine to guide the injections. The dose of XRays used is tiny: the machine intensifies a very small XRay dose in a similar way to army night vision goggles. X-ray pictures are taken throughout to ensure the needle is in the correct area.

The skin of the flank between the bottom of the ribcage and the top of the pelvic bone is sterilised and a small amount of local anaesthetic is injected with a tiny needle to numb the skin. Following this a fine needle is placed down onto where the sympathetic chain lies. A small amount of x-ray dye is injected to confirm the position of the needle tip, and then a small amount of local anaesthetic or the chemical (usually phenol) to affect the nerves is injected.

Does it hurt?

You do not need a general anaesthetic for this procedure. Very occasionally there can be some discomfort during the procedure but the doctor will ensure pain is kept to a minimum by using local anaesthetic. You can sometimes also get a sensation of pressure as the local anaesthetic goes in. Once the procedure is over you may have some tenderness over the injection site but no worse than after any other type of injection.

How long will it all take?

Although the procedure itself usually only takes about 20 minutes, you will normally be asked to stay for up to an hour or so after the injection in the Day Surgery Unit before going home, normally lying flat for the first half hour or so to encourage the drug to stay in close contact with the nerves. Occasionally, when the injection is to more permanently numb the nerves, it may be better to arrange for you to stay in the hospital overnight. This will be discussed wth you when the procedure is arranged.

At home:

You may move around freely at home unless you have been advised to the contrary by a member of staff.

Possible complications:

  • You may have mild discomfort at the site of the injection; this should last no longer than 48 hours. In a number of patients it can make your symptoms worse for about a week.
  • There is a possibility of bruising in the muscle through which the needle is inserted (the psoas muscle) that can cause discomfort into the hip or groin area for a day or two.
  • Extremely rarely people may get pain into the groin from irritation of one of the nerves near the sympathetic chain by the chemical used to more permanently numb the nerves. This may last for some weeks.
  • As for any procedure, we have to warn you that there are very small chances of rare complications such as infection.
  • Very rarely people can be allergic to the injection, which results in redness and itching. This is not serious, but we need to know for future treatments.
  • Serious complications with this procedure are extremely rare, but if problems arise please consult the Pain Clinic Office, or your own doctor who will contact the Pain Clinic if necessary.

(Please see general comments on the Procedures page)


The Trust's information sheet on lumbar chemical sympathectomy can be downloaded here

















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Pain Service Website, Gloucestershire Hospitals NHS Foundation Trust
Webmaster Dr J G de Courcy, Consultant in Pain Medicine and Anaesthesia
email: pain.webmaster[at]

Page updated 22/6/2016