Sympathetic Nerve Blocks

Sympathetic Nerve Blocks
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Sympathetic nerve blocks may be used in the treatment or diagnosis of different disorders of the nervous system. The injection contains a local anesthetic. The most common reason for this injection is to alleviate pain and inflammation or to determine the cause of pain.


There are general surgical preparation guidelines for patients to follow before undergoing a sympathetic nerve block. Patients should also talk to their doctor about any special guidelines they may have. Patients should notify their doctor of all allergies and surgeries. It is critical that patients let their doctor know at least two weeks in advance if they are taking any type of blood-thinning medication, including aspirin. Patients who have an infection or are pregnant should also notify their doctor. Patients should plan to have someone drive them home and should wear comfortable, loose-fitting clothing.


When having a sympathetic nerve block, some patients will be given an IV sedative. To begin the procedure, the patient will lie on an X-ray table, and an X-ray technician will line up the image. The doctor will numb the area receiving the sympathetic nerve block. A contrast dye is then injected. Once everything is on target, the anesthetic is slowly injected.

The skin and deeper tissues will be numb, but some discomfort may still be experienced by some patients. Many patients experience a degree of pressure when the dye and and anesthetic are being injected.


After the procedure, a nurse will check the patient’s blood pressure and pulse and keep an eye on him or her for about 30 minutes following the procedure. The patient will then go home with detailed instructions. For pain, the patient should ice the injection site. The doctor will instruct the patient about what medications he or she can take for discomfort. All medications should be taken as normal, except blood-thinners. The patient will receive special instructions on when to restart blood-thinners. The patient should not work the day of the procedure, but can likely return to work the next day.

Risks and Side Effects

Risks associated with a sympathetic nerve block are low, but possible. They include bleeding, blood vessel puncture, infection and lung puncture.

Side effects are also possible. These may include injection site discomfort, affected extremity weakness or numbness, increased mobility or temperature or color change in the affected extremity, hoarse voice, drooping eyelids, difficulty swallowing, warmness in the affected extremity. These should all subside within a few hours.

The following should be reported immediately to the patient’s doctor:

  • Temperature of 101 degrees Fahrenheit or higher
  • Abnormal amount of pain
  • Drainage, swelling or redness at the injection site


Spine Universe. (2011). Sympathetic Nerve Block Information. Retrieved on April 14, 2011 from Spine Universe:

WebMD. (2011). Pain Management and Nerve Blocks. Retrieved on April 14, 2011 from WebMD:

Image Credits

Syringe and Vial: - zeathiel