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.
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.
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.
Lumbar sympathetic nerve blocks have three general purposes:
Healthcare providers may recommend a lumbar sympathetic nerve block if the following conditions affect your lower extremities:
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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.
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:
Usually, the procedure takes fewer than 30 minutes.
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.
Potential benefits of a lumbar sympathetic block include:
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.
The most common side effects include the following at the site of the injection:
These are usually mild and resolve within hours to days. Less common complications include:
Very rare but more serious complications include:
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.
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.
Last reviewed by a Cleveland Clinic medical professional on 03/31/2023.
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