Lumbar Medial Branch Block
What are Lumbar Medial Branch Blocks?
The medial branch nerves are small nerves (not much thicker than a piece of cotton) that provide the feeling to the facet joints at the back of the spine. They also give movement to a small patch of muscle directly above the joint. Placing a drop or two of local anaesthetic onto the nerve causes it to stop working temporarily (thus 'blocking' it from transmitting signals). If the medial branch nerve is blocked, you can't feel what is going on the in the facet joints.
What is the purpose of Lumbar Medial Branch Blocks?
Pain can be produced from the facet joints in many cases of back pain. Performing Lumbar Medial Branch Blocks helps to clarify whether the pain is coming from these little joints. If your facet joints are producing most of your back pain, you will get significant relief while the local anaesthetic is still working (normally 24 hours or so). In a handful of cases, the temporary nerve block produces relief that lasts for weeks or months. Even if the duration of relief is much shorter than this, it can help with making a diagnosis of the source of your back pain, and thus directing further treatment efforts.
How are Lumbar Medial Branch Blocks done?
You lie on the operating theatre table while x-rays are taken to establish where the needle should go. After a sterile preparation, local anaesthetic is used to numb the skin and superficial tissues. The needle is passed through the anaesthetised tissue to the shelf of bone where the nerve is usually located under x-ray guidance. When the needle looks to be in the right position, a drop or two (0.2ml) of high-strength, long-acting local anaesthetic is placed to numb the nerves.
We offer light sedation as part of the procedure. The sedation means you won't remember the injection but it's a long way short of a full general anaesthetic. You won't be able to drive for 24 hours after having sedation, and you will have to fast for 4 hours before you arrive.
What happens during an injection?
A local anesthetic is used to numb your skin. The doctor will then insert a thin needle near the medial branch nerve. An X-ray machine will be used to ensure the safe and proper position of the needle. Once your physician is sure the needle is correctly placed, the medicine will be injected.
What happens after the procedure?
You will be observed in the recovery room for 30-60 minutes and be free to leave the hospital soon after that.
If you have pain at the site of the injection you should use a cold pack and some paracetamol (Panadol, Herron, Panamax) or Ibuprofen (Herron Blue, Nurofen) in the recommended doses for a couple of days.
You will be advised to keep a pain diary to record the pain levels or any other symptoms you notice over the next few days. This should be completed as it helps us plan your further care and monitor how well we are doing our procedures. Getting this information is critical to the usefulness of Lumbar Medial Branch Blocks, as the follow-up treatment needs to be informed by the outcome of each set of injections.
In the case of numbness, which has not gone away after 24 hours, or any loss of control over bladder or bowel, you should contact PainMedSA, or attend an Emergency Department and ask that they contact us if it is after hours.