Sympathetic Nerve Block

Medically Reviewed By William C. Lloyd III, MD, FACS
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What is a sympathetic nerve block?

A sympathetic nerve block diagnoses and treats long-term (chronic) pain and other conditions caused by abnormal activity of the sympathetic nerves. A sympathetic nerve block involves injecting an anesthetic near the sympathetic nerves to numb pain. A sympathetic nerve block can provide good long-term pain relief, but it is not effective for everyone. You may need a series of injections for optimal pain relief.

The sympathetic nerves control some automatic body functions, such as blood pressure, digestion, and sweating. They do not normally send pain messages to the brain. Some conditions, such as complex regional pain syndrome, can trigger sympathetic nerve activity and cause pain.

A sympathetic nerve block is only one method used to treat chronic pain. Discuss all your treatment options with your doctor to understand which option is right for you.  

Types of sympathetic nerve blocks

The types of sympathetic nerve blocks include:

  • Lumbar sympathetic nerve block treats pain in the lower part of your body. It involves an anesthetic injection in the lower back (lumbar) area.

  • Stellate ganglion block treats pain in the upper part of your body. It involves an anesthetic injection in the neck area.

Why is a sympathetic nerve block performed?

Your doctor may recommend a sympathetic nerve block to treat ongoing, long-term pain (chronic pain).  It can also help diagnose the cause of your pain. Pain relief after a sympathetic nerve block indicates that a problem with the sympathetic nerves is the cause of your pain. Your doctor can then perform  more nerve blocks or other treatments to target the sympathetic nerves.

Your doctor may recommend a sympathetic nerve block to treat:

  • Coccydynia, which causes chronic tailbone pain

  • Complex regional pain syndrome (CRPS), which causes severe burning pain, often in the foot or hand. CRPS is also known as reflex sympathetic dystrophy (RSD).

  • Frostbite, which causes pain due to blood vessel spasms

  • Phantom pain, which occurs in the area of an amputated limb

  • Postherpetic neuralgia, which is lingering severe nerve pain after a shingles outbreak

Sympathetic nerve blocks can also treat:

  • Hyperhidrosis, which causes excessive sweating

  • Raynaud's syndrome, which causes constriction of the blood vessels in the fingers, toes, ears or nose due to hyperactive sympathetic nerves

Who performs a sympathetic nerve block?

Anesthesiologists who specialize in pain medicine perform sympathetic nerve blocks. An anesthesiologist is a doctor who specializes in providing anesthesia and pain relief.

How is a sympathetic nerve block performed?

Your sympathetic nerve block will be performed in a hospital or outpatient setting. The procedure takes about 30 minutes. You may need a series of procedures over several weeks for full pain relief.

A sympathetic nerve block generally includes these steps:

  1. You will dress in a hospital gown. It is a good idea to leave all jewelry and valuables at home or with a family member. Your care team will give you blankets for modesty and warmth.

  2. You will talk with the anesthesiologist about your medical history and your sympathetic nerve block.

  3. You will lie on a table and a team member will start an intravenous (IV) line.

  4. You may have medication (a light sedative) through the IV to make you drowsy and relaxed.

  5. A team member will clean the injection area.

  6. Your anesthesiologist will inject a small amount of local anesthetic into your skin to numb the injection area. The location is either the lower (lumbar) back for lower body pain, or the back of the neck for upper body pain.

  7. Your anesthesiologist will guide a needle into place near the affected nerves using X-ray guidance.

  8. Your anesthesiologist will inject an anesthetic around the group of sympathetic nerves.

  9. Your doctor will remove the needle and bandage the injection site.

  10. The procedure team will monitor your vital signs and other critical body functions. This occurs throughout your procedure and recovery until you are alert, breathing effectively, and your vital signs are stable.

Will I feel pain?

Your comfort and relaxation is important to you and your care team. You may feel pinching or stinging as your anesthesiologist injects the local anesthetic to numb the injection area. You may feel some pressure but should not feel pain during the sympathetic nerve block injection. Tell your doctor if any discomfort does not pass quickly. 

What are the risks and potential complications of a sympathetic nerve block?

Complications of a sympathetic nerve block are not common and are usually temporary. Complications may become serious in some cases. Complications can develop during the procedure or recovery. Risks and potential complications of a sympathetic nerve block include: 

  • Adverse reaction or problems related to sedation, anesthesia, or other medications, such as an allergic reaction and problems with breathing

  • Bleeding

  • Infection

  • Injection of anesthetic into the spine

  • Nerve damage

  • Voice changes, eyelid droop, or difficulty swallowing after a neck area injection. This is usually temporary.

  • Weakness

Reducing your risk of complications

You can reduce the risk of certain complications by following your treatment plan and: 

  • Following activity, dietary and lifestyle restrictions and recommendations before your procedure and during recovery

  • Notifying your doctor immediately of any concerns, such as bleeding, fever, or increase in pain

  • Taking or stopping your medications exactly as directed

  • Telling your doctor right away if you are on antibiotics, feel sick, or have a fever or symptoms of a cold, flu, or other infection. This includes lesions, rashes, or redness of the skin. A sympathetic nerve block cannot be done if you have an infection.

  • Telling your doctor about a history of high blood pressure

  • Telling all members of your care team if you have any allergies

How do I prepare for my sympathetic nerve block?

You are an important member of your own healthcare team. The steps you take before your procedure can improve your comfort and outcome. You can prepare for a sympathetic nerve block by:

  • Answering all questions about your medical history, allergies, and medications. This includes prescriptions, over-the-counter drugs, herbal treatments, and vitamins. It is a good idea to carry a current list of your medical conditions, medications, and allergies at all times.

  • Getting preoperative testing as directed. Testing will vary depending on your age, health, and specific procedure. Testing may include a chest X-ray, EKG (electrocardiogram), blood tests, and other tests as needed.

  • Not eating or drinking before the procedure as directed. This generally includes fasting for about six hours beforehand.

  • Stopping smoking as soon as possible. Even quitting for just a few days can be beneficial and help the healing process.

  • Taking or stopping medications exactly as directed. This may include not taking aspirin, ibuprofen (Advil, Motrin), blood thinners, herbal medicines, and supplements, such as fish oil and Vitamin E.

Questions to ask your doctor

Preparing for a sympathetic nerve block can be stressful. It is common for patients to forget some of their questions during a doctor’s office visit. You may also think of other questions after your appointment. Contact your doctor with concerns and questions before a sympathetic nerve block and between appointments. 

It is also a good idea to bring a list of questions to your appointments. Questions can include:

  • Why do I need a sympathetic nerve block? Are there any other anesthetic options for me?

  • How long will the procedure take? When can I go home?

  • What restrictions will I have after the surgery? When can I return to work and other activities?

  • What kind of assistance will I need at home? Will I need a ride home?

  • How do I take my medications?

  • How long will the sympathetic nerve block last? How many injections will I need?

  • When should I follow up with you?

  • How should I contact you? Ask for numbers to call during and after regular hours.

What can I expect after my sympathetic nerve block?

Knowing what to expect after a sympathetic nerve block can help you get back to your everyday life as soon as possible.

How will I feel after the sympathetic nerve block?

You may have some mild pain around the injection site and a flushing or warm feeling in the targeted area. Apply ice to the area to help relieve pain as directed by your doctor. Do not use heat or take a hot shower or bath that day. 

Your doctor may recommend that you do not use your regular pain medication the day of your injection. This will make it easier to tell if the sympathetic nerve block relieved your pain and if the sympathetic nerves caused your pain. Your doctor may also have you keep a log of your pain for a week or more.

You may still be drowsy if you also had sedation. You should not drive for about 24 hours and will need a ride home from the procedure. Someone should stay with you for the first day.

Your doctor will probably advise you to rest for the rest of the day. Most people return to normal activities the following day. Your doctor will advise you when and how to return to exercise and strenuous activities.

A sympathetic nerve block can provide long-term or even permanent pain relief, but it does not work for everyone. Pain due to other conditions outside the sympathetic nervous system will not get better with a sympathetic nerve block. Talk to your doctor about your condition and what to expect from a sympathetic nerve block.

When can I go home?

You will stay in the recovery room until you are alert, breathing effectively, and your vital signs are stable. Most patients go home the same day as the procedure.

When should I call my doctor?

It is important to keep your follow-up appointments after a sympathetic nerve block. Contact your doctor for questions and concerns between appointments. Call your doctor right away or seek immediate medical care if you have:

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Nov 17
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Lumbar Sympathetic Nerve Block. University of Maryland Rehabilitation & Orthopaedic Institute.
  2. Lumbar Sympathetic Nerve Block. UW Health.
  3. Nerve Blocks. UCSF Medical Center.
  4. Sympathetic Nerve Blocks for Pain. Johns Hopkins Medicine.