Lumbar Sympathetic Block

A lumbar sympathetic block is an injection that may provide temporary pain relief to your legs and feet. It can also help with other bodily functions like sweating and blood flow issues. Healthcare providers may recommend the block for several conditions, such as complex regional pain syndrome, phantom limb pain and hyperhidrosis.


What is a lumbar sympathetic block?

A lumbar sympathetic nerve block is an injection of numbing medication in your lower back to provide temporary pain relief to your lower extremities. In some cases, the addition of anti-inflammatory medication to the local anesthetic may allow damaged nerves to heal.

Nerves are like cables that carry electrical signals between your brain and the rest of your body and vice versa. These signals help you feel sensations (like touch and pain) and move your muscles.

Your sympathetic nerves are a part of your autonomic nervous system. They maintain certain functions like breathing, sweating and blood pressure without you noticing. But sometimes, sympathetic nerves can send pain signals after an injury.

Your lumbar sympathetic nerves are in the front of your spine in your lower back (lumbar spine) near your L1 through L4 vertebrae. Lumbar sympathetic blocks target these nerves and can address issues with pain signaling.

But they can affect other nerve functions as well to treat certain conditions, such as increasing blood flow or reducing excessive sweating.

What does a lumbar sympathetic block treat?

Lumbar sympathetic nerve blocks have three general purposes:

  • To achieve temporary pain relief for acute (sudden and short) or chronic (long-term) pain: The nerve block may reduce inflammation and allow your nerves to heal.
  • To diagnose the source of pain: If you’re experiencing pain but your healthcare provider doesn’t know the exact source of it, they may perform a lumbar nerve block. If you experience pain relief from the injection, it generally means that the targeted nerves are the source of the pain. If you don’t experience relief, the pain is likely coming from somewhere else.
  • To provide pain relief for surgeries: Anesthesiologists or surgeons may administer lumbar sympathetic nerve blocks before surgeries to help manage pain after the procedure.

Healthcare providers may recommend a lumbar sympathetic nerve block if the following conditions affect your lower extremities:


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Procedure Details

How do I prepare for a lumbar sympathetic block?

You usually don’t have to do anything special to prepare for a lumbar sympathetic block.

In some cases, your healthcare provider may recommend sedation for the procedure. If you’re receiving sedation, you’ll need to fast for six to eight hours before it. You’ll also need someone else to drive you home after the procedure.

Your provider will let you know what to do if anything. Be sure to follow their instructions. Don’t hesitate to ask questions.

What happens during a lumbar sympathetic block?

Healthcare providers typically perform nerve blocks for pain management in an outpatient setting. This means you’re not admitted to a hospital for the procedure and can go home shortly after it.

In general, you can expect the following during a lumbar sympathetic block:

  1. You’ll lie on your stomach on a procedure table.
  2. You may receive a mild sedative through an IV line in your arm to help you relax.
  3. The provider will clean your skin with an antiseptic solution. They’ll give you an injection of a local anesthetic to numb the area where you’ll receive the nerve block. You may still feel a pinch or some discomfort as the needle enters your skin.
  4. Guided by X-ray imaging, the provider will insert a needle into your back, along the outside of your spine.
  5. They may inject a contrast dye to confirm that the medication will go to the correct spot.
  6. They’ll then inject a steroid anti-inflammatory medication.

Usually, the procedure takes fewer than 30 minutes.


What can I expect after a lumbar sympathetic nerve block?

Your lower back and leg may feel warm or “different,” and you may begin to feel less pain. Your leg may feel numb or weak, but this feeling will go away when the anesthetic wears off.

You can continue your regular diet and medications immediately, but you shouldn’t do any rigorous activities for 24 hours after the procedure. Take it easy. You can return to your normal activities the next day.

Risks / Benefits

What are the benefits of a lumbar sympathetic block?

Potential benefits of a lumbar sympathetic block include:

  • Temporary pain relief, which may help you function better day to day.
  • Temporary reduction of inflammation in the affected nerves, which may help them heal.
  • Providing a diagnosis. The block can help your provider identify a more specific cause of pain.

It’s important to note that not everyone experiences pain relief from lumbar sympathetic blocks. You may need to try other treatment options if this is the case.


What are the possible complications of a lumbar sympathetic block?

The most common side effects include the following at the site of the injection:

  • Bruising.
  • Swelling.
  • Soreness.

These are usually mild and resolve within hours to days. Less common complications include:

  • Bleeding.
  • Dizziness.
  • Headache.
  • Temporary numbness.
  • Weakness of the leg on the side that was injected.

Very rare but more serious complications include:

  • Infection.
  • Accidental injection into a blood vessel.
  • Accidental injection into a lymph node.
  • Ureter injury.
  • Kidney injury.
  • Horner's syndrome.
  • An allergic reaction to the medication.

Recovery and Outlook

How long does a lumbar sympathetic block last?

Pain relief from a lumbar sympathetic block can last anywhere from a few days to several weeks. Each person responds differently. Some people report pain relief immediately after the injection, but the pain may return a few hours later as the anesthetic wears off. Longer-term relief usually begins in two to three days once the steroid begins to work.

Usually, people need a series of injections to experience continued pain relief. Sometimes, it takes only two injections; sometimes, it takes more than 10 over time.

When To Call the Doctor

When should I call my healthcare provider?

Contact your healthcare provider immediately if you experience any new symptoms or complications from the nerve block, such as an infection or nerve issues like burning pain, weakness or tingling.

A note from Cleveland Clinic

Lumbar sympathetic blocks can help treat a variety of pain-related conditions. But the results can vary considerably from person to person. If you’re feeling anxious about receiving a nerve block injection, don’t hesitate to ask your healthcare provider about it and the procedure. They can answer any questions you may have.

Medically Reviewed

Last reviewed on 03/31/2023.

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