Lumbar Medial Branch Block


For Chronic Low Back Pain

A lumbar facet injection is an outpatient procedure for diagnosing and treating low back, buttock, hip, and groin pain.


What are lumbar facet joints?

Facet joints connect the vertebrae, the bones of he spine. They help guide your spine when you move. The low back area of the spine is called the lumbar region. It contains five vertebrae.

Facet joints are found on both sides of the spine. Each is about the size of a thumbnail. Lumbar facet joints are named for the vertebrae they connect and the side of the spine where they are found. The right L4-5 facet joint, for example, joins the 4th and 5th lumbar vertebrae on the right side.

Medial branch nerves are found near facet joints. They transmit pain signals from the facet joints to your brain.


What is lumbar facet joint pain?

You may feel pain if a lumbar facet joint is injured. sometimes, it feels like muscle tension. Other times it can be severe pain.

The cartilage inside the joint may be injured. Other times only connecting ligaments surrounding the joint are injured.

Facet pain also depends on which joint is affected. Pain from lumbar facet joints occurs in an area from your low back down to your buttock region. The diagram shows areas of pain usually associated with the lumbar facet joints.


How do I know if I have lumbar facet pain?

If you have pain in one or more of these areas, and if your pain has lasted longer than two months, you may have lumbar facet pain. Common tests such as x-rays or MRIs may not always show if a facet joint is causing pain.


What is a lumbar medial branch block?

In a lumbar medial branch block, an anesthetic is injected near the medial branch nerve. This temporarily stops the transmission of pain signals from the facet joint. If this reduces your pain and helps you move your back like normal, it may tell the provider which facet joint is causing the pain.


What happens during an injection?

A local anesthetic will be used to numb your skin. The provider will then insert a small needle near the medial branch nerve. Fluoroscopy, a type of x-ray, will be used to ensure the safe and proper position of the needle. A Contrast will also be injected to make sure the needle is at the correct spot.

Once the provider is sure the needle is correctly placed, the medicine will be injected.


What happens after an injection?

You will be monitored for up to 30 minutes after the injection. When you are ready to leave, the staff will give you discharge instructions. You will also be given a pain diary. It is important to fill this out because it helps your doctor know how the injection is working.

You may help to move your back in ways that hurt before the injection, to see if the pain is still there, but do not overdo it. Take it easy for the rest of the day.

You may feel immediate pain relief and numbness in your back and leg for a period of time after the injection. This may indicate the medication has reached the right spot.


How long can I expect pain relief?

The extent and duration of pain relief may depend on the amount of inflammation and how many areas are involved. Other coexisting factors may be responsible for your pain.

If your pain goes away for a short time, but then returns, you may be a candidate for radiofrequency ablation (RFA) of the medial branch nerve. This procedure provides a more sustained disruption of pain signals and often prolonged pain relief.

If your pain is caused by injury to more than one area, only some of your symptoms will be helped by a single injection.

This pamphlet is for general education only. Specific questions or concerns should always be directed to your doctor. Your doctor can explain possible risks or side effects.

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