Medial Branch Block: Indications and Complications

The vertebral column is made up of vertebrae and the cartilage disks between them. The processes of the vertebrae have facets in them. Facets from adjacent vertebrae fit together to form zygoapophysial joints, which allow the movement in the back. Pain in the back or the neck can be attributed to many causes; inflammation of the facets is one of them. Inflammation causes release of chemicals which irritate the nerve endings in the zygoapophysial joint leading to a sensation of pain. Medial branch block is a diagnostic method wherein a long acting anaesthetic agent is injected near the medial branch nerves that supply to the facet joint. Reduction in pain after the procedure confirms the diagnosis of pain due to inflammation.

Procedure of Medial bracnh block

Medial branch block is performed on an outpatient basis. After you reach the hospital you will be asked to change into a hospital gown. If the procedure is to be performed on the vertebrae in your back you will be asked to lie on your stomach, while if the test is to be done on vertebrae in your neck you will be requested to lie on your side. A small amount of local anaesthetic will be administered under the skin to reduce the pain experienced during the procedure. After the anaesthesia takes effect your provider will introduce a needle to reach the vertebral facet, via the skin. This will be done under fluoroscopic guidance. On reaching the target facet, a long acting anaesthetic agent is injected slowly. The needle is withdrawn and a sterile dressing is applied.

Indications for Medial branch block

Medial branch block is a diagnostic procedure indicated for individuals with back pain or neck pain to determine the cause of the pain. It is suggested when your doctor suspects an inflammatory cause.

Preparation for Medial branch block

Before scheduling the procedure your doctor will like to record a detailed history and do a thorough physical examination. Your doctor would like to know the list of medications that you are consuming; you might be requested to stop taking blood thinning medications. Inform your doctor if you are pregnant, because x rays used during fluoroscopy are harmful for the growing fetus. If you have a history of allergy to a particular anaesthetic agent it is advisable to inform your doctor about it beforehand.

Complications of Medial branch block

Medial branch block is a very safe procedure with low frequency of complications. The complications encountered are:

• Nerve damage
• Infection at site of procedure
• Bleeding.

Recovery from Medial branch block

After the procedure you will be advised to go on with your normal routine. If your pain was due to an inflammatory process affecting the facet joints you will experience a reduction in pain. However this will be temporary and will last for a couple of hours to a few days. You may return to work the day after the procedure.

The results of this diagnostic test are used to decide further course of action in management of your pain.

Sources

• British pain society– Standards of good practice for medial branch block injections and radiofrequency denervation for low back pain
• Lumbar Medial Branch Blocks. In: Nikolai Bogduk (ed.), Practice Guidelines: Spinal Diagnostic and Treatment Procedures. San Francisco, California, 94127, USA: International Spinal Intervention Society