Facet Medial Branch Blocks

Dr Thomas E Smith MB BS (Hons) MD FRCA FFPMRCA

Information about facet joint medial branch blocks to treat your spinal pain.

What are facet joints?

The spine is a column of bones arranged one on top of the other. The bones are linked at the back by joints called facet joints, one on each side. The facet stabilise the spine, while also allowing movement.

The facet joints may become painful either due to wear and tear (also called degenerative change) or injury. Pain is felt around the facet joints and can spread. Pain from the joints of the lower back will often be felt in the buttocks and upper legs. Pain from facet joint in the neck can spread into the back of the head, the upper back, and shoulders. When the facet joints are tender and sensitive, the muscles nearby can become tight and painful.

What are facet joint medial branch blocks

Facet joint medial branch blocks is a procedure in which nerve fibres supplying the painful facet joints are blocked by local anaesthetic injections.

Each joint is supplied by 2 nerves. Usually several joints are treated at the same time.

What is the aim of facet joint medial branch blocks?

The treatment is usually performed as a “test” procedure to see if radiofrequency burning treatment of the nerves should be offered. Usually only short term – hours to days – pain relief is observed. Sometimes the relief lasts longer.

What are the risks?

Facet joint medial branch blocks is a commonly performed procedure and is very low risk. Possible side effects and complications include:

  • A skin infection where the needle is inserted – this is estimated to occur in one per 1000 cases.
  • Bleeding / bruising at the injection site (more common when taking blood thinners)
  • Temporary numbness / weakness from the local anaesthetic that is injected during the procedure – this usually resolves in a few hours. This can affect your back/neck and limbs
  • Allergy to injected drugs – this is estimated at one case per 40,000.
  • Permanent nerve injury to a nerve supplying the leg or trunk, which is very rare.  
  • Stiffness and soreness for a few days after the treatment due to local trauma from the needles. You should take your normal painkillers regularly and do gentle stretches.

Are there any alternatives?

Procedures for back pain are generally considered after trying less invasive treatments, such as:

  • physiotherapy
  • medication

Giving your consent

Dr Smith wants to involve you in decisions about your care and treatment. If you decide to go ahead, you will be asked to sign a consent form that says you agree to have the treatment and you understand what it involves. But you can still ask questions after this.

What happens on the day of the procedure?

Please remember to bring with you:

  • dressing gown and slippers
    • any medication you normally would take (unless already advised not to)
    • something to read and your mobile phone.

A nurse will admit you. You will be given a gown to change into. You can put your own dressing gown on over this gown while you wait.

Please note the time stated on your letter may not be the time of your actual procedure. Allowance needs to be made for time for you to be prepared and ready for your procedure. And sometimes procedural rooms/theatre list are running late.Therefore, you may have to wait for a while. A friend or relative will be able to stay with you while you wait.

All women of child-bearing age will be asked to provide a urine sample, to rule out pregnancy. You must tell us if you could be pregnant. We want to avoid x-rays during preganancy.

It is important that you take all your medication as usual unless you have been asked not to. If you take blood thinning drugs (eg. Rivaroxaban, Dagabatrin, Clopidogrel, Ticlodipine, Warfarin) or diabetes medication, please inform us at least two weeks before your injection .

Will I feel any pain?

The procedure is usually performed awake. Local anaesthetic will be used but some brief pain with the injections may be experienced. If sedation may be required, Dr Smith will discuss you in advance.

What happens after the procedure?

You will need to stay in the Procedure Facility for at least 30 minutes after your procedure so your recovery can be monitored and we are sure that it is safe for you to go home. You will be provided with a pain chart to record your pain scores for the next 24 hours.

Please arrange for a responsible adult to drive you home or accompany you in a taxi. We do not recommend public transport in case you feel delayed leg weakness or faintness.

You will be able to leave when a nurse is satisfied that you are well enough and that there is a responsible adult to accompany you.

What do I need to do after I go home?

After the procedure and for the rest of the day, it is important for your safety that you follow the advice below.

Although you might feel fine, your reasoning, reflexes, judgement and co-ordination skills could be affected for up to 12 hours after your procedure (24 hours if your have sedation). Please stay at home for the remainder of the day.

For 12 hours after the procedure (24 hours if you have had sedation), do not:

  • drive any vehicle, including a bicycle
  • operate machinery
  • attempt to cook, use sharp utensils or pour hot liquids
  • drink alcohol
  • smoke 
  • make any important decisions or sign any contracts.

Some people feel pain relief immediately after the procedure. Some people feel no immediate change but pain relief develops later. Some people do not benefit. If you experience some initial soreness you should take your usual painkillers and do gentle stretches.

Will I have a follow-up appointment?

Yes. You will have either a clinic or telephone appointnment to assess the effectiveness of the procedure.