The sympathetic nervous system helps control many functions in your body (blood pressure, sweating, peripheral blood flow) and is usually not involved in pain sensation. However, in some pain conditions, such as Complex Regional Pain Syndrome (CRPS) or Reflex Sympathetic Dystrophy (RSD), the sympathetic nerves become activated in an abnormal way and begin to transmit pain. Blocking these sympathetic nerves can improve pain and a positive response is also useful in helping to provide a diagnosis for the pain. Sympathetic blocks are done with either x-ray or ultrasound guidance, and all involve the injection of local anesthetic around bundles of nerves. The blocks may be done initially in a series of three over a 6 week period, but in some patients may be repeated several times per year. Sympathetic blocks can be done at five different levels of the spine, depending on the area and type of pain involved:

How long does a sympathetic block take?

Sympathetic blocks usually take no more than 30 minutes.

How will I feel afterwards?

Relief from sympathetic blocks is usually noticed with 15 minutes of your procedure. You may also note rapid improvement in blood flow to the area, with increase in temperature and decreased sensitivity.

How long will the relief last?

Relief is variable and you may require a series of injections over several weeks to provide lasting results.