FAQs on Lumbar Sympathetic Nerve Block

A sympathetic nerve block is an injection of medication onto sympathetic nerves. These nerves are part of the sympathetic nervous system, and they are located on either side of the spine. Normally, these nerves control basic body functions, such as blood flow and sweating.

What is the purpose of a sympathetic block?

The sympathetic nerve block is performed to stop pain signal transmission from the arms or legs on the side of the injection. This also reduces swelling, sweating, and discoloration of the affected extremity.

What conditions are treated with sympathetic nerve blocks?

Conditions treated with the sympathetic nerve block include:

  • Complex regional pain syndrome
  • Herpes zoster
  • Neuropathic pain (nerve-related discomfort)

What medications are used during the sympathetic nerve block?

The injection consists of certain local anesthetics, like lidocaine and bupivicaine. In addition, corticosteroid agents may be used, such as triamcinolone and dexamethasone. On occasion, epinephrine and clonidine are used. Solutions to clean the skin include betadine and alcohol. For some patients, a neurolytic agent is used, such as absolute alcohol and phenol.

Does the procedure hurt?

You will be given a mild sedative, so pain is minimal. The skin and deeper tissues are numbed using a local anesthetic. Most patients report feeling no pain with this procedure.

How do I prepare for the sympathetic block?

It is important to notify your doctor of all medications you are taking, as certain blood-thinners have to be held for several days beforehand. In addition, the doctor needs to know about all your medical conditions. When you arrive at the medical center, a staff member goes over the risks and benefits of the block, and you sign a consent form. After donning a gown, the nurse places an intravenous catheter in your hand. Monitoring devices are attached to your body to assess oxygen level, blood pressure, and heart rate.

What can I expect during the procedure?

You will be positioned on your stomach on a special table. After the area is prepped, the procedure needle is guided near the nerves using fluoroscopy (diagnostic imaging technique). Once in place, contrast dye is injected to assure correct needle placement. After the medication is injected, the needle is removed, and the area is covered with a Band-Aid.

What happens after the procedure?

Because sedation is given, you must have someone drive you home. A nurse monitors you for around 20-30 minutes. Once you are stable, you are discharged. You cannot soak in a tub or bathe for 24 hours, and should rest for 1-2 days. Gradually return to activities.

How many sympathetic blocks are needed?

If you respond well to the first block, the doctor may recommend repeat injections. Most patients do well with 3-4 injections, which are spaced several months apart. It is difficult to tell who will respond to the sympathetic block, as patients with advanced diseases and severe disorders do not always get pain relief with this procedure.

What complications and side effects can occur?

The sympathetic block is a safe, effective procedure. The most common side effects include soreness at the injection site and numbness down the affected extremity. While rare, risks include bleeding, blood vessel injuries, infection, and nerve damage.

What is the efficacy rate for sympathetic nerve blocks?

In a recent study, sympathetic nerve blocks were proven effective. When steroids were added, the success rate was 90%, and the technical success rate was over 72%. The duration of pain relief for the sympathetic ganglion block was around 11 weeks. The rate was of effectiveness for the regional bier block was around 2 weeks, and the brachial plexus block lasted about 10 weeks.