Information on Medial Branch Block Injection (MBB) from Dr. Rathi

What is a Medial Branch Block Injection?
Physicians commonly use this type of injection to help diagnose lower back pain. It is used to diagnose low back pain that stays above the knee. During a medial branch block injection numbing medication or local anesthetic is placed directly around a medial branch nerve.

What are Medial Branch Nerves?
Medial branch nerves are the very small nerve branches that controls sensation to a part of the spine called the facet joint. They do not control any muscles or sensations in your arms or legs. The facet joint is where each bone of the spine (vertebrae) connects with the next. Sometimes, these facet joints can develop arthritis and be a source of pain.

What happens after this injection?
Remember, this type of injection can be both therapeutic and diagnostic. Whatever result you have gives the physician more information about your pain. Generally, one of the following three things may happen.

  1. The pain does not go away. This means that the pain is probably not coming from the facet joints.
  2. The pain goes away a few hours but comes back again and does not get better. This would mean that the pain is probably coming from the joints.
  3. The pain goes away, returns within a few hours, but then gets better over the next few days. This means that the medications had a long lasting effect on the pain.

Does this procedure hurt?
Most people say that the burning or stinging sensation due to the numbing medication is the most uncomfortable part.

How is the procedure done?
You will lie on your abdomen. Using the x-ray machine your doctor will identify the target for needle placement. After anesthetizing the skin the Medial Branch Block injection procedure is performed. For a Medial Branch Block Injection mild sedation is given because it is important for you to tell the physician or nurse if the block has relieved your pain.

When can I go back to my normal activities after this procedure?
You may not drive for the remainder of the day after the procedure. Do not use heat on the injected areas, take a tub bath or soak in water (i.e. pool, Jacuzzi, etc.) the remainder of the day after the procedure.