Lumbar sympathetic block


A lumbar sympathetic nerve block involves administering numbing medication in the lower back to offer momentary relief for pain in the legs and feet, concurrently addressing issues related to perspiration and blood circulation.

A lumbar sympathetic nerve block may be advised to address various conditions affecting the lower extremities, including complex regional pain syndrome (CRPS), phantom limb pain, among others. The local anesthetic’s combination with anti-inflammatory drugs may promote the healing of injured nerves.

Nerves serve as pathways for transmitting electrical signals between the brain and the body, enabling the perception of sensations such as touch and pain, as well as facilitating muscle movement. Within the autonomic nervous system, sympathetic nerves discreetly oversee vital functions such as respiration, perspiration, and blood pressure regulation. After an injury, these sympathetic nerves may at times transmit pain signals.

These nerves are located in the anterior portion of your lumbar spine, specifically near the L1 through L4 vertebrae in your lower back. A lumbar sympathetic nerve block is administered with the goal of alleviating pain by targeting the lumbar sympathetic nerves responsible for transmitting specific pain signals. In addition to addressing pain, these nerve blocks can also impact other nerve functions, including enhancing blood flow and diminishing excessive sweating, to effectively manage certain medical conditions.

Reasons for undergoing the procedure

A lumbar sympathetic nerve block serves different functions. It seeks to temporarily alleviate acute or chronic pain by reducing inflammation and fostering nerve healing. It is also employed to provide pain relief in surgical settings to effectively manage postoperative pain.

In some cases, it may be used for diagnostic purposes when the exact source of pain is unclear. If the injection provides pain relief, it typically indicates that the identified nerves are the source of the pain. However, if no relief is experienced, the pain likely originates from a different source.

A lumbar sympathetic nerve block may be suggested in cases where the lower extremities are impacted by conditions such as:

  • Vascular pain
  • Phantom limb pain
  • Complex regional pain syndrome (CRPS)
  • Pain from cancer
  • Neuropathy associated with diabetes
  • Herpes zoster-related postherpetic neuralgia
  • Raynaud’s disease
  • Hyperhidrosis
  • Critical limb ischemia


Rarely, a lumbar sympathetic nerve block results in serious complications. Potential complications include allergic reaction to the medication, infection, accidental injection into a blood vessel or lymph node, ureter and kidney injury, and Horner’s syndrome.

In most cases, the typical side effects of lumbar sympathetic nerve blocks at the injection site include mild issues like bruising, swelling, and soreness, which usually resolve within hours to days.

Less frequently encountered complications encompass concerns such as bleeding, lightheadedness, headaches, temporary numbness, and temporary weakness in the leg that received the injection.

Before the procedure

The healthcare provider will offer personalized, comprehensive instructions to prepare for a lumbar sympathetic block. If sedation is recommended for the procedure, patients may need to abstain from eating for six to eight hours beforehand. Additionally, it is advisable for them to arrange for someone else to provide transportation for their journey back home following the procedure.

During the procedure

A lumbar sympathetic block generally takes less than 30 minutes. During the procedure, a mild sedative may be administered through an IV line to help one relax. The skin is then cleaned with an antiseptic solution.

During the procedure, you will lie on your stomach on the procedure table. A local anesthetic will be used to numb the region where the nerve block is to be administered. With the guidance of X-ray imaging, a needle will be carefully inserted along the outer edge of the spine in order to maintain precision. To ensure accuracy, a contrast dye may also be injected. Following this, a steroid anti-inflammatory medication will be administered.

This procedure is typically conducted in an outpatient setting, meaning that there is no need for hospital admission, allowing patients to depart shortly after it is finished.

After the procedure

It is generally recommended to refrain from engaging in any strenuous activity for 24 hours following the surgery. Temporary numbness or weakness in the leg may occur, but this will pass once the anesthesia wears off.

People who undergone a lumbar sympathetic block might start to experience less discomfort and notice warmth or a distinct sensation in the lower back and leg.

Following the procedure, one can resume their regular diet and medications immediately, and be able to return to their normal activities the following day.


The duration of pain relief from a lumbar sympathetic block varies from a few days to several weeks. Some individuals may experience immediate relief after the injection, although the pain might return as the anesthetic wears off.

Extended relief typically commences within two to three days after the steroid treatment initiates its effects. Generally, individuals may require a series of injections to maintain ongoing pain relief. The number of injections needed can vary, ranging from as few as two to potentially exceeding 10 over a period of time.

It is crucial to recognize that lumbar sympathetic blocks may not provide pain relief for everyone. If this is the situation, exploring alternative treatment options may be necessary.