What is a Sympathetic Block?

Sympathetic blocks explained by Denver, Golden, Aurora, Boulder, Broomfield, Jefferson, and Littleton Colorado’s top pain doctors

Sympathetic Block DiagramA sympathetic block is a treatment method that involves blocking the activity of targeted sympathetic nerves in order to reduce pain. This technique is especially effective at relieving chronic pain that did not decrease after taking a pain medication. This approach is also recommended for patients who experienced harmful side effects from conventional methods (e.g., pain relievers or injections).

Sympathetic nerves are located along the spinal cord and extend to the muscles in the heart as well as various glands and smooth muscle tissue. These nerves regulate signal transfer in the body for processes such as respiration, heart rate, facial and bodily movements, perspiration, and digestion.

Reports show that sympathetic blocks are effective at treating pain in different body parts including the neck, head, back, tailbone, and limbs. After the region that is causing the pain is identified, nerves in that area can be targeted in order to relieve the pain.

How is a Sympathetic Block Performed?

A sympathetic block injection involves administering medication to the targeted sympathetic nerves. A local anesthetic is first applied to the skin and then an imaging device such as an X-ray, ultrasound, fluoroscope, or computed tomography (CT scan) is used to guide the thin needle that is inserted into the targeted region. Contrast dye is also injected to help ensure that the needle will be properly placed before the medication is injected and to make sure that the medication will be appropriately distributed to the affected nerves. A substance that destroys nerve tissue or an anesthetic is injected into the nerve tissue in order to alleviate the pain.

An anterior approach, in which a patient lies on the stomach; atransdiscal approach, in which the patient lies on the side; or a posterior approach, which involves lying on the back, may be utilized to perform the nerve block. The most commonly used approach is the posterior method because the needle is inserted in the region under the spine close to the buttocks. This approach has the lowest rate of complications such as injuries to the arteries, veins, nerves, and spinal discs.

In general, the occurrence of these types of injuries is minimal because the placement of the needle is guided with imaging techniques. CT scans expose the patient and physician to large amounts of radiation and is, therefore, the least commonly used technique. 

Conditions Related To Sympathetic Blocks

Complex Regional Pain SyndromeSympathetic blocks have been shown to effectively treat the following conditions:

  • Cancer-related pain
  • Bodily pain (e.g., the neck, head, tailbone, back, and the limbs)
  • Complex regional pain syndrome
  • Neuropathic pain from nerve or tissue damage

Treatment for cancer-related pain usually entails taking antidepressants, pain-relieving medication, and non-steroidal anti-inflammatory agents. However, this approach is not always effective at reducing the pain and some patients even suffer from unbearable side effects. When this occurs, a sympathetic block may be recommended. Cancer patients who have received this treatment have reported a significant decrease in pain. A number of patients can also decrease their pain medication dosage after undergoing a nerve block. In addition, an increase in well-being and mobility has been reported.

If persistent pain is being felt in different body parts such as the limbs, back, head, or neck after pain-relievers, anti-inflammatory medication, and injections have been utilized, a nerve block is usually a good option. In most cases, a sympathetic block provides individuals with significant pain relief that allows them to decrease or completely discontinue taking their medication.

Complex regional pain syndrome is a condition that is characterized by chronic pain in the arms or legs after an injury, a stroke, a heart attack, or surgery that is not proportionate to the circumstance or injury that caused it. The exact cause of the pain is often hard to identify and this makes the condition hard to treat. It is believed that the pain is the result of nerve damage. A sympathetic block, which hinders nerve activity, effectively reduces the pain and supports the premise that this condition may develop due to nerve damage.

Sympathetic blocks have even demonstrated the ability to reduce neuropathic pain that occurred after an individual was bitten by a brown recluse spider.

The nerve block procedure is brief and patients typically report that they experienced significant pain relief approximately 24 hours after receiving the injection and that the effects persist for extended periods. 


Sympathetic Nervous SystemA sympathetic block is a pain management technique that hinders targeted sympathetic nerves from transmitting pain signals. These nerves extend into all of the body’s glands and muscles. Therefore, identifying the region that is causing the pain helps a physician specifically block nerves in that region to reduce the pain. The risks that are associated with this treatment include injuries to spinal discs, nerve roots, veins, and arteries, but physicians use imaging techniques during the needle placement in order to avoid these complications. Sympathetic blocks have proven to be effective when traditional approaches such as pain relievers and injections were ineffective or led to harmful side effects. The pain-relieving effects typically last for long periods and many patients either reduce their medication dosage or stop taking their pain medication altogether after receiving this treatment.

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