Your body has special nerves that control your blood vessels. Some of these are known as sympathetic nerves. These nerves can be anesthetized to change the blood low to a limb. Additionally sometimes these nerves are involved in painful conditions traditionally known as reflex sympathetic dystrophy (RSD) or known today as complex regional pain syndrome (CRPS).

The nerves going to the arm can be anesthetized in one of two places: the low neck, which is known as a stellate block; or the upper chest area, known as a T2 sympathetic block. Stellate blocks are easier to perform, have fewer problems associated with them, but are less effective than T2 sympathetic blocks. Nerves have a "home" known as a ganglion where the cell body resides. The ganglion is where these blocks are performed.

For a T2 sympathetic block, you will lie face down on an X-ray table. Utilizing X-ray pictures Dr. Harries will position a very fine needle in the area of the nerves and inject some local anesthetic. The location of the T2 ganglion is indicated by the orange mark on the image.
If the block works, then your hand will warm up and, depending upon the source of your pain, your pain may improve.
When utilized for CRPS (RSD) stellate blocks are used as a way of getting you to work with physical \ occupational therapy to desensitize your arm or hand.

The risks associated with this procedure are small.  Occasionally, a hoarse voice may occur. Very rarely, in patients with an abnormally high lung, a punctured lung (pneumothorax) can occur. Usually a pneumothorax is so small that no treatment is required.