What are nerve blocks?
Throughout the body, and particularly in the skin, both large and small nerves can be found that may themselves be the possible cause of your pain, such as in scar tissue pain; alternatively these nerves may be important for passing on pain from a particular area of the skin or from a joint where you feel pain. An example is pain felt on one side at the back of the head. We can help relieve the pain by injecting local anaesthetic and corticosteroids into the area around the nerve. The most well-known injection for pain is one that is administered to one side of the back of the head to treat either the greater or the lesser occipital nerve, both of which supply the skin on the back of your head (numbers 4 and 5 in Figure 1). These nerves are given PRF treatment (see below) so that they can no longer pass on pain signals.
Figure 1. View from the back of the skull (1) and the cervical vertebrae (3). The spinal cord is found between mastoid of the skull and the topmost vertebra (number 2, see text).
What should I be aware of before undergoing a nerve block?
Any of the following situations should be reported to your pain specialist if he proposes a nerve block:
- If you are pregnant: since X-ray equipment is used, pregnant women may not undergo a nerve block.
- If you are ill or have fever on the day of treatment you cannot undergo a nerve block and a new appointment has 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 nerve 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 nerve 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.
- Depending on where the local injections are to be performed, you will be positioned on the treatment table on your back or stomach.
- Your own pain specialist has decided the right place of the nerve block.
- The right place of the block is estimated with aid of fluoroscopy or ultrasound.
- This place is marked with a felt pen on the skin.
- The area around this site is then disinfected with a cold, red liquid.
- The pain specialist covers the area with sterile drapes
- After local anaesthesia of the skin the pain specialist will insert, under fluoroscopy (via television monitor) or Ultrasound, the needle in the correct place.
- Some contrast fluid is also injected to enable the position of the needle to be clearly visible.
- Then small electrical currents are administrated near the ganglion.
- Then small electrical currents are administrated near the nerve.
- You will feel a tingling sensation.
- When you feel this, you must tell the treating pain specialist straight away, and not wait for it to become painful.
- The pain specialist will ask you where you feel the sensation and you don't have to point the place with your finger.
- By means of a special device, the pain specialist can read the distance from the needle to the nerve.
- If the needle is in the right place a pulsed radiofrequency (PRF) electrical current is administrated near the nerve.
- Interrupted (pulsed) series of small electrical currents are used. These small currents modulate of the nerve to decrease the pain.
- You will then be asked to get dressed and make an appointment at the pain clinic after six weeks with your own pain specialist.
- The effect of treatment will be checked and further policy will discuss with you.
- 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 nerve blocks?
- Sometimes an allergic reaction for the injected substances can occur.
- Sometimes a nerve has been hit resulting in a prolonged pain.
- You have to contact pain specialist for additional pain medication.
When can I expect pain relief after the treatment?
- Afterpains can occur following a nerve block. These may last for several weeks but will eventually disappear.
- The optimum results of treatment are seen after four weeks.
- Around this time, a new appointment with your pain specialist will be made.