Medial Branch Block

The procedure of medial branch block involves the injection of local anaesthetic around the nerves that supply feeling to the facet joints. Facet joints are small joints of the spine that provide stability and help guide motion. They are found in the neck (cervical), upper back (thoracic) and lower back (lumbar spine).


Why a medial branch block?

The medial branch block is purely diagnostic. It is designed to see if pain can be temporarily abolished by removing the feeling from the facet joints. If the blocks give significant relief you may be a suitable candidate for a more permanent interruption to the nerve supply of the facet joint by radio frequency denervation (RFD).


The procedure is performed either under CT guidance scan control by our radiologist. The patient lies face down on the CT scanner and the back area is cleaned using an antiseptic solution. The area is injected with a small amount of local anaesthetic to numb the area followed by placement of a small needle onto the bone where the nerve lives, using the CT images to check the position. An x-ray dye (contrast) may also be used to confirm the position of the needle. Local anaesthetic only is injected. Each facet joint has feeling supplied by two or three medial branch nerves.

Therefore blocking the medial branch to the facet joint will require 3 injections. This may be uncomfortable for a short period of time while the anaesthetic takes effect. The procedure usually takes about 15-30 minutes plus recovery time.

Are there any risks or side effects?

There are risks associated with any form of treatment. The general risk is low, but includes:

  • Discomfort at the injection site
  • Mild increase in pain following the injection (probably due to the pressure effect of the injection.)
  • Very rare nerve damage (due to trauma, the medication, infection or bleeding)
  • Allergic reaction to the medication

Post Procedure

  • It is preferable to have someone take you home.
  • The pain relief, if it occurs, will be short lived, approximately 4-6 hours. It is important during this time that you record or remember how much pain relief you had.
  • You may be given a pain relief chart to fill out. Please take the completed chart to your next appointment with your treating doctor.
  • There may be a slight soreness or bruising at the needle site. Paracetamol and or ice may provide some comfort if required.
  • You may experience an increase in pain and some stiffness initially, but this usually wears off after 48 hours.
  • You should not participate in strenuous activity or exercise for 48 hours to one week depending on your treating doctor’s instructions. They will also advise you on how best to resume pre-treatment activity levels.
  • If you experience any fever, localised heat, swelling or increasing pain more than 48 hours after the injection you should call our clinic or consult your doctor without delay

Please bring to your appointment

Please bring your referral from your doctor along with the following:

  • Medicare Card
  • Pension/Concession Card
  • Previous films

Things we need to know from you

Please inform the Radiology staff of any of the following:

  1. If you are allergic to any medications, anaesthetic agent or X-Ray contrast
  2. If you are not feeling well or wish to cancel please ring immediately (someone else can be offered your appointment time).

Female Patients: Please let us know if you are pregnant or suspect you may be or if you are breastfeeding


It is important you understand why and how we will be assisting you. Please feel free to contact our friendly staff at any time if you have any questions or concerns on 03 9420 1700.