What is a lumbar sympathetic test block?
To the front of the lumbar vertebrae (number 5 in Figure 1) there is a nerve bundle (known as the sympathetic chain or lumbar sympathetic trunk) that is part of a nervous system that we cannot control at will. This separate nervous system controls how much blood flows through the blood vessels, for example. The lumbar sympathetic trunk is also important for pain. Blocking the lumbar sympathetic trunk can relieve pain and sometimes improve blood flow to the legs. The lumbar nerve bundles are located next to the lumbar vertebrae and can be easily reached with a needle. In a lumbar sympathetic test block local anaesthetic is injected through a needle.
Figure 1. Cross-section through the body at the level of the lumbar vertebrae. You are looking at the back from behind and in the middle you can see a vertebra (3). The aorta (1) and vena cava (2) are located to the front of this vertebra. The kidneys (4) are located to the side of the vertebra.
What should I be aware of before undergoing a lumbar sympathetic test block?
Any of the following situations should be reported to your pain specialist if he proposes a lumbar sympathetic test block:
- If you are pregnant: since X-ray equipment is used, pregnant women may not undergo a lumbar sympathetic test block and a new appointment has to be made.
- If you are ill or have a fever on the day of treatment you cannot undergo a lumbar sympathetic test block, in which case a new appointment will have to be made.
- If you are allergic to iodine, bandages, anaesthetics or contrast fluids, you should notify your pain specialist before the appointment for treatment is made.
- If you are taking blood thinners, you should notify that your pain specialist before the appointment for treatment is made. He will then consider whether the use of certain medications should be ceased temporarily.
How should I prepare for a lumbar sympathetic test block?
- No special preparations, such as an overnight bag, are necessary because the treatment is carried out on an outpatient basis.
- You may eat before treatment and take your normal medication.
- N.B.: this does not include blood thinners, as mentioned above.
- Make sure you have someone to take you home, because you may not drive for 24 hours.
How does a lumbar sympathetic test block work?
- The treatment will be performed in the surgical day-care centre, where you will be asked to change into a surgical gown. This gown closes at the back.
- A nurse will escort you to the treatment room, where there is a treatment table, an X-ray machine and television monitors.
- You will be positioned on the treatment table with your stomach on top of a cushion.
- The blood pressure and the amount of oxygen in your blood will be controlled during the treatment.
- A drip will be placed in your hand.
- The right place of the block is estimated with aid of fluoroscopy.
- This place is marked on the skin with a felt pen.
- The area around this site is then disinfected with a cold, red liquid.
- The pain specialist covers the area with sterile drapes.
- After a local anesthetic has been applied to the skin, the pain specialist, by means of fluoroscopy (via the television monitor), will insert the needles in the correct place.
- Some contrast fluid is also injected to enable the position of the needle to be clearly visible.
- If the needle is in the right place the lumbar sympathetic test block is performed.
- In sympathetic test blocks small amount of local anaesthetics are injected around the lumbar sympathetic nerves to temporarily block the nerves.
- This numbness may last for several hours, and then return to the same pain level as before the test block.
- You will then be asked to get dressed and return to the waiting room.
- After half an hour, your pain specialist will inquire whether the lumbar sympathetic test block clearly reduced your pain.
- If this is not the case, you will have to make a new appointment with your own pain specialist to discuss further possible treatment options.
- If the lumbar sympathetic test block clearly reduced your pain, then an appointment will immediately be made at the day centre for a permanent lumbar sympathetic block.
What are dangers and side effects of a lumbar sympathetic test block?
After a lumbar sympathetic test block, the following complications or side effects can occur:
- In very rare cases, swelling of the leg can occur because due to the treatment more blood has gone to the leg.
- Temporarily a nerve pain or numbness can occur in the groin and/or upper leg.
- Touching of the skin in this area can be unpleasant and painful.
- All these complaints eventually disappear after a few weeks.
When can I expect pain relief after the treatment?
- Afterpains can occur following a lumbar sympathetic test block. This may last a week but will eventually disappear.
- The numbness will last several hours and your original pain will return.