Lumbar Sympathetic Nerve Block

By MMI board-certified, academically affiliated clinician 
January 16, 2018

A lumbar sympathetic nerve block is a type of injection that eases pain. It’s used for a variety of conditions that cause pain in your legs and feet.

Your brain sends information to the body through pathways known as nerves. Nerves also receive information from the body and send it to the proper regions of the brain. Nerves that communicate some types of pain from the legs and feet pass through the lumbar sympathetic nerves on their way to the brain.

Your lumbar sympathetic nerves lie in front of the spine in the lower back. During a lumbar sympathetic nerve block, your healthcare provider will inject a needle into your lower back. He or she will advance it until it reaches a position in front of the spine where the lumbar sympathetic nerves are. Then he or she will inject medicine in the area to ease the pain.

You might need a lumbar sympathetic nerve block if you have certain types of pain in your lower legs, ankles, or feet. Often, the procedure works by blocking the nerves from sending pain signals. Other times, it works by blocking the nerves that control some of your body’s involuntary functions like blood vessel size.

Your healthcare provider might recommend this procedure if you have tried other ways to control the pain. But your pain is still not manageable. For example, the procedure might help if you have:

  • Complex regional pain syndrome (CRPS)
  • Peripheral vascular disease
  • Reflex sympathetic dystrophy
  • Frostbite
  • Shingles (herpes zoster)
  • Diabetic neuropathy
  • Peripheral neuropathy
  • Wounds or ulcers that are not healing well
  • Certain types of cancer pain

A lumbar sympathetic nerve block is generally safe. Some rare risks of the procedure are:

  • Damage to nearby nerves
  • Damage to nearby organs
  • Bleeding
  • Infection
  • Allergic reaction to the medicines

If you receive steroid medicine in your injection, you may have side effects. These include temporary increases in blood sugar levels for 1 to 2 days, an allergic reaction, and flushing on your face. There is also a risk that the procedure will not ease your pain.

You may not be able to have the procedure if you have a high risk of bleeding. That may also be true if you have an infection in the area of the injection. Your own risk may vary based on your age and any other health problems. Before the procedure, talk with your healthcare provider about all your concerns.

You will need to go over your past health with your healthcare provider. Let him or her know if you have an infection, fever, or other recent health problems. If you have diabetes or use any blood-thinning medicines, ask whether you will need to take any special precautions.

You should also discuss all your medicines with your healthcare provider. That includes over-the-counter medicines. You may need to stop taking certain medicines a few days before the shot. Also be sure to tell your healthcare provider if you:

  • Have any allergies
  • Have had any problems with contrast dyes, past injection procedures, anesthesia, or other medicines
  • Are pregnant or might be pregnant

Your healthcare provider may tell you not to eat or drink after midnight the night before the procedure. You may get medicine to help you relax during the injection. You should arrange to have someone drive you home afterward. Your provider may give you other instructions about how to prepare.

Ask your healthcare provider about what to expect. Your exact procedure may differ. But general steps for a lumbar sympathetic nerve block are the following:

  • You will lie on your stomach on a procedure table.
  • You may get medicine to help you relax (sedation). But you will likely remain awake during the procedure.
  • During the procedure, your heart rate, blood pressure, and oxygen level will be closely watched. You may get extra oxygen by a mask or nasal tubing.
  • The area of your lower back where you will have the shot will be cleaned.
  • You will get medicine to numb the skin around the injection area. It may burn and sting a little. But it should only last a few seconds.
  • The healthcare provider will insert a needle into your lower back. He or she will advance it to the correct position. He or she may use X-rays, CT imaging, or ultrasound to help guide the needle.
  • The provider will inject a small amount of X-ray contrast dye through the needle to make sure it is in exactly the right spot.
  • The provider will then inject medicine through the needle. He or she may use different types of medicine for different reasons. Numbing medicine may be needed to block pain. A steroid may be used to reduce inflammation. After you have the medicine injected, you may feel a warm or burning sensation in the area.

Generally, you will be watched for 30 to 60 minutes after the procedure. Make sure someone can drive you home. You should not plan to do anything strenuous or anything that calls for your full attention for the rest of the day.

Ask your healthcare provider about any activity restrictions after the procedure. You should be able to eat and drink normally. Ask if you should resume your normal medicines. Make sure to follow all your healthcare provider’s instructions for care.

It is common to have pain at the injection site for a day or two. Many people feel relief from their pain soon after the procedure. This relief might last a few hours, a few days, or longer depending on the medicine used.

Call your healthcare provider if you have any of these symptoms:

  • Severe pain
  • Weakness or numbness in the legs
  • Fever
  • Signs of infection at the injection site. These include redness, swelling, and oozing.

Your healthcare provider can tell you more about what you should do and what you can expect after a lumbar sympathetic nerve block. You will need to see your healthcare provider to talk about the effects of the procedure and make a plan for future treatment of your pain.

Before you agree to the test or the procedure make sure you know:

  • The name of the test or procedure
  • The reason you are having the test or procedure
  • What results to expect and what they mean
  • The risks and benefits of the test or procedure
  • What the possible side effects or complications are
  • When and where you are to have the test or procedure
  • Who will do the test or procedure and what that person’s qualifications are
  • What would happen if you did not have the test or procedure
  • Any alternative tests or procedures to think about
  • When and how will you get the results
    Who to call after the test or procedure if you have questions or problems
  • How much will you have to pay for the test or procedure


January 16, 2018


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Reviewed By:  

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