Facet Joint Blocks
What are facet joint blocks?
The vertebral column is made up of vertebrae (see number 1 in Figure 1) in between which can be found the so-called intervertebral discs (number 2 in the Figure) that allow the vertebrae to move against one another. Each vertebra has two small-paired joints (facet joints) with the vertebra above it (number 3 in the Figure) and two small joints with the vertebra below it (number 4 in the Figure). These facet joints can be the cause of your pain, for example as a result of osteoarthritis. There is a nerve root that emerges from between two vertebrae (number 5 in the Figure). A smaller nerve branches off this nerve root (number 6 in the Figure) and goes to the facet joint. It is this facet joint nerve that is important in passing on pain signals.
Figure 1. Diagonal rear view of the lumbar vertebrae with part of the pelvis (see text).
To find out which facet joints are causing the pain, it is necessary to perform test blocks of the nerves going to the facet joints (number 6 in the Figure). This takes place by anaesthetising these nerves with an injection to block pain signals. Since we do not known beforehand exactly which facet joints are causing the pain, we usually anaesthetise the nerve fibres of three facet joints on one side. So you are given three injections.
In a permanent facet joint block a needle is used to pass a small electric current into the facet joint nerve which heats it and blocks it, as a result of which these facet joint nerves can no longer pass on pain signals.
Test blocks and permanent blocks of the facet joint nerves can be applied to the cervical, thoracic and lumbar vertebrae of the spinal column.
What should I be aware of before undergoing facet joint blocks?
Any of the following situations should be reported to your pain specialist if he proposes facet joint blocks:
- If you are pregnant: since X-ray equipment is used, pregnant women may not undergo facet joint blocks and a new appointment has to be made.
- If you are ill or have a fever on the day of treatment you cannot undergo facet joint blocks, 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 facet joint blocks?
- 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 do facet joint blocks 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.
- Depending on where the facet joint nerve blocks are to be performed, you will be positioned on the treatment table on your back or stomach.
- With the help of the X-ray machine and a metal ruler, the exact location of the facet joint nerve block will be determined.
- 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.
- In facet joint nerve test blocks around the nerves to the facet joints, small amounts of anesthetic are injected 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 facet joint nerve test block treatment 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 facet joint nerve test block clearly reduced your pain, then an appointment will immediately be made at the day centre for a permanent facet joint nerve block.
- The procedure for a permanent facet joint nerve block is exactly the same, but in addition to the local anesthetic into the facet nerves, a small electrical current is passed into the nerves by means of needles.
- This may produce a tingling sensation. When you feel this, you must tell the treating pain specialist straight away, and not wait for it to become painful.
- By means of a special device, the pain specialist can read the distance from the needle to the nerves.
- If the needles are in the right place, a radio-frequency current is given to block the facet joint nerves.
- Six to eight weeks after treatment, you should make an appointment with your own pain specialist. The effects of the treatment will then be checked and further policy will discussed with you. You will then be asked to get dressed and to make an appointment with your own pain specialist to evaluate the effect of the treatment and discuss further treatment possibilities.
- On the day of the treatment you should slow down and is advised not to participate for 24 hours in traffic.
What are dangers and side effects of facet joint blocks?
After facet joint nerve blocks, the following complications or side effects can occur:
- Side effects of the permanent facet joint nerve blocks can consist of temporary numbness of the skin where the treatment took place.
- Contact with the skin can sometimes feel strange. This will disappear after a few weeks.
- Allergy to the injected substances is sometimes known to occur.
When can I expect pain relief after the treatment?
- After pains can occur following permanent facet joint nerve blocks. These may last for several weeks but will eventually disappear.
- The optimum results of treatment are seen after six to eight weeks.
- Around this time, a new appointment with your pain specialist will be made.