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Lumbar Sympathetic Block



A lumbar sympathetic block is where local anaesthetic is injected onto the sympathetic nerves in the lower (lumbar) section of the spine.

Sympathetic nerves are nerves that control 'autonomous' functions of the body, that is functions that are not controlled consciously, such as heart rate, sweating and blood flow.

Sympathetic nerves can also transmit pain signals from the legs and feet and so may be implicated in conditions such as shingles, and complex regional pain syndrome (CRPS).

A lumbar sympathetic block temporarily disables the pain signals from the lower part of the body. The block, which is administered to the sympathetic nerves near the L2, L3 and L4 vertebrae, comprises a numbing agent and, in some case, a corticosteroid anti-inflammatory. In some situations, phenol or alcohol are used, during a procedure called sympathetic chain ablation.


  • Neuropathic pain of the lower limbs.
  • Some vascular syndromes.

Preoperative Instructions

Please also let us know ahead of the procedure if…

  • You are taking any antibiotics.
  • You are diabetic.
  • You have a pacemaker or defibrillator.
  • You have any allergies.
  • You are pregnant or trying to conceive.
  • You are ill (in which case we may need to postpone the procedure).

You should also…

  • Avoid undergoing any other medical procedures, such as for example dental treatment or a colonoscopy, within 48 hours (before or after) of a coeliac plexus block.
  • Not drive yourself to or from the appointment (and you should not drive in the 24-hour period immediately after the procedure) .
  • Not smoke at all on the day of the procedure.
  • Stop taking all blood thinning medication before the procedure (you may still take aspirin) .


You are asked to lie face down on a theatre table. At this point you may also be given a general anaesthetic agent.

The injection site is then cleaned and numbed with a local anaesthetic and a thin needle is inserted at the injection site and then guided (using a mobile x-ray image) to the correct position. Before the anaesthetic is injected, a small quantity of contrast dye is introduced to check that the anaesthetic will get to the target area.

Once the procedure is complete, you will need to spend around half an hour under observation before being able to go home. It is normal to experience a warm feeling in the affected leg/s, and occasionally a feeling of weakness in the leg/s.

Postoperative Instructions

After the procedure you are able to return home, but you will not be allowed to drive yourself home. There is no restriction on day-to-day activities. You will be asked to complete a 24-hour pain diary.


A lumbar sympathetic block procedure is a relatively low-risk procedure – however all medical treatment comes with some level of risk. Possible complications may include…

  • Pain.
  • Bleeding.
  • Infection.
  • Pain at injection site.
  • Nerve damage.
  • Low blood pressure.
  • Allergic reaction to anaesthetic.