What are medial branches?

The spine is made of 33 bones (vertebrae), which sit on top of each other. The small joints between the vertebrae called facet joints (stabilisers of the spine). They allow the spine to move backwards, forwards, sideways and twist. Medial branches are small nerves that supply the facet joints in your spine with pain signals. If your pain is caused by the facet joints then by stopping the pain signals, your pain can be relieved.  

What causes facet joint pain?

Commonly facet joints wear out (degenerate). The surface of the joints are protected by a thin layer of cartilage allowing the joints to slide smoothly without friction. With wear and tear the joint becomes overgrown/ enlarged commonly described as arthritis.  

What is a medial branch block?

A medial branch block is an injection to the nerves supplying the facet joint to numb them so they can no longer supply pain signals. The procedure is for diagnosis only and is not for permanent pain relief. Following this procedure your consultant will be able to determine whether the facet joints are the cause of pain.

Why am I having the injection?

Your pain specialist consultant has determined that your pain may be coming from these joints. Injections to the joints or nerves can reduce pain for some patients.

What is injected?

A small quantity of dye (which can be seen on the x-ray images) is used to confirm that the injection is close to the nerve.
Local Anaesthetic is injected onto the nerve.

Does it work?

The injection is used primarily to diagnose the source of your pain. The local anaesthetic numbs the joint so if the facet joint is the source of pain, you should experience significant pain relief within 15 minutes of the injection, which may last for a few hours. There is no prolonged relief but if the facet joint is confirmed as a source of pain then there may be some prolonged pain relief from a potentially longer lasting treatment called radiofrequency denervation or rhizolysis.

Risks and side effects

• No reduction in your pain levels
• Infection – (affects around one out of every 100 patients treated)
• Bleeding (affects less than one out of every 100 patients treated)
• Spinal nerve injury (affects around one out of every 10,000 patients treated) including paralysis
• More discomfort for the first few days after your injection. This is usually temporary and should settle. Continue with your normal pain relief. Sometimes it can take a couple of weeks, but generally only lasts a couple of days. (affects around one out of every 100 patients treated)  
• Bruising to the injection area.
• Numbness around the site. This is usually temporary and should return to normal
• Leg numbness and weakness are very rare side effects.  Arm weakness if the injection is in your neck.  
• Allergy to injected medication (affects around one out of every 100 patients treated
• Unlicensed steroids - side effects include hot flushes, feeling sick, mild abdominal pain, fluid retention, a temporary rise in blood sugar, and menstrual irregularities (in women). These should settle within a few days.  
• Other side effects - soft tissue injury, toxicity, weak legs, weak arms, vasovagal attacks, blindness

What happens on the day of my appointment?

• Please arrive at the Outpatients Department no more than 10 minutes before your appointment time.
• Take any medication as normal unless advised otherwise. Bring a list of your tablets with you.
• You can eat and drink normally before arriving.
• You will be admitted to the OPD Injection Suite and will be assessed by a member of the clinical team. This is to make sure you are fit and ready for the injection. You will have the opportunity to ask any questions at this stage.
• The doctor carrying out your injection will also see you before your procedure.
• A nurse will take some details from you to check that you are fit for your procedure.

What does the procedure involve?

• If we are injecting your back, you will be asked to lie on your stomach. If it is your neck, you may be asked to lie on your side or front
• The area will be cleaned then injected with local anaesthetic to numb the area, before injecting the joint
• X-ray images will be taken throughout the procedure, to position the needle into the correct area. (Females will be asked to confirm you are not pregnant because x-rays can harm unborn children)
• Local anaesthetic is injected into the skin and fine needles are passed towards the nerves under x-ray guidance. Once the needle is confirmed to be in the joint, the injection takes place

You may feel some discomfort during the procedure.

Due to theatre lists, you may have to wait a period of time before your slot, please be prepared for this.  

After your procedure

After you have had your procedure, you will need to stay with us for about 30 minutes before you can go home. You must not drive home or go home on public transport. Please arrange for someone to collect you or arrange a taxi.

Back at home

• Take things easy for the rest of the day, do not do any excessive exercise or heavy work for the first few days.
• Remove the dressing the next morning.
• Continue to take your pain tablets until you notice any improvement in your symptoms.

Who do I contact if I have problems following the procedure?

From 9am – 4pm you can call the OPD Injection Suite on 0121 685 4000 extension 55814 or contact the secretary for the clinician you are under. Outside these hours contact the bleep holder through switchboard at the ROH (0121 685 4000).

Follow up appointment

You will be given contact details and a date when to ring. You’ll speak to a pain nurse specialist and report on the progress of your injection. You may be given a pain diary to complete your response to the injection.

Important Information

• Please inform the Outpatients (OPD) Injection Suite if you are diabetic, have a cough or cold or have any kind of infection.
• You must inform us if you are taking any of the following tablets – antibiotics, Apixiban, Aspirin, Dabigatran, Riveroxaban, Warfarin or Clopidogrel or any other tablet to thin the blood before attending as some of these may need to be stopped some days before.
• Your procedure may be cancelled if you do not inform us of the above, before your appointment date.
• If you cannot make your appointment date, you must let the scheduled care coordinators know as soon as possible. 

Information for females

We will need to know the start date of your last menstrual period due to the use of X-ray equipment. If you think you might be pregnant, contact the scheduled care coordinator for advice.

Useful Contact Numbers

PALS - 0121 685 4128
Care Co-Ordinator - 0121 827 3835
OPD Injection Suite - 0121 685 4000 extension 55814
For any urgent calls please contact your GP or 111