Sympathetic nerves, located in the lower spine, control basic functions such as regulating blood flow. They also carry pain signals from tissues to the spinal cord. Lumbar sympathetic block is an injection containing a local anesthetic and steroid, which is injected into or around the sympathetic nerves to block the transmission of pain impulses from the legs or lower back, thereby relieving pain.
The lumbar sympathetic block is usually indicated as a treatment for conditions such as reflex sympathetic dystrophy (pain and dysfunction of an extremity), Herpes zoster infection, vascular insufficiency (impaired blood flow) and peripheral neuropathy (nerve damage). You are contraindicated for this procedure if you are allergic to the medications being injected, are taking blood thinning medications, have an active infection, or you have diabetes or heart disorders.
The lumbar sympathetic block is performed under local anesthesia and sedation, in an outpatient setting. You will lie flat on your stomach. Your doctor will numb the area of your lower back to be treated. With the help of live X-rays, your doctor will insert a needle into your back. A dye is then injected to check the correct path of the medication. When this is confirmed, the steroid medication and anesthetic is injected into the target site. The entire procedure usually takes less than 30 minutes.
After the procedure you may feel warmth in your lower back and your legs may feel numb or weak. You may have pain relief immediately after the injection, but pain may return after a few hours as the anesthesia wears off. Relief from the medication is observed in 2 to 3 day, as the steroid begins to work. Most often you will need 2 to 10 injections at regular intervals to get continued pain relief.
As with most therapeutic procedures, lumbar sympathetic block may be associated with certain side effects such as temporary pain or soreness at the site of injection, bleeding and infection. This procedure is usually safe and the risks are rare.