Lumbar Medial Branch Blocks (Facet Nerve Injection)
The facets are the small, bony joints that connect one spine vertebra to another at the back of the spinal canal. Each vertebral segment has two facet joints, one on each side. The lumbar facet joints guide motion in the lower back. These joints provide stability and control but also allow for motion in the spine, so that you can bend and twist. The nerves that supply these facet joints are called the medial branch nerves.
Just as a joint in your finger, knee, or hip can cause you discomfort, so can the facet joints in your neck and back. They can become arthritic or injured, causing pain. The pain is mostly felt in the back and may sometimes be associated with vague aching in the legs.
The goal of a medial branch block is to help diagnose whether or not the cause of your pain is coming from the facet joints by numbing the medial branch nerves. If your pain is relieved by the medial branch block, then the cause of your pain is more likely facet joint-related.
Purpose of medial branch blocks
Medial branch blocks are used as a test to determine if your pain is coming from the facet joints and if radiofrequency neurotomy may help reduce your pain. During a medial branch block, your doctor will use a numbing medication to temporarily block the medial branch nerves from sending the pain signals on to your brain. If your pain is caused by a facet joint problem, you may feel relief of that pain for a few hours with a medial branch block.
If you get significant pain relief through this temporary medial branch block, then you may be a candidate for radiofrequency neurotomy, which is a longer-lasting interruption of signals from the medial branch nerves.
Overview of the lumbar medial branch block procedure
Here’s what to expect during a lumbar medial branch block procedure:
- You will lie face down on a table, with a pillow underneath your abdomen.
- The injection area is cleaned and numbed before the injection.
- Using fluoroscopic (X-ray) guidance, your physician will determine the appropriate path for the needle.
- Your doctor will insert a thin needle to the appropriate area(s) for the block.
- Next, your doctor will inject a small amount of contrast dye to make sure that the medication will flow exactly where intended.
- Then, your physician will inject a small amount of long-acting anesthetic.
- After the procedure, you’ll spend about 20 minutes in the recovery area.
Preparing for the lumbar medial branch block
- While the procedure may take less than 15 minutes, you should allow for at least one hour at the procedure center.
- For diagnostic injections, you should have some pain at the time of the procedure or be able to reproduce it consistently with certain activities or positions. If you are typically pain-free after taking pain medication, please do not take these medications for four to six hours before the injection. In the event that you do not have pain on the day of a diagnostic injection, we may need to reschedule your procedure.
- You should not schedule any dental or colonoscopy procedures 48 hours before or after your injection. Please notify us if you are scheduled for any dental or colonoscopy procedures 48 hours before or after your injection.
- Tell your doctor, nurse, or care coordinator if you have a pacemaker or defibrillator (ICD).
- If you have recently been prescribed antibiotics, tell your doctor, nurse, or care coordinator.
- If you develop a fever, night sweats, or an active infection before your procedure, your procedure will need to be rescheduled. Please contact our office at (651) 968–5201 immediately to let us know about the symptoms you’re experiencing.
After the injection
After the procedure, you should try to gently reproduce your pain for the duration of the numbing medication. Then, tell your doctor how much the injection relieved your pain.
Potential risks of medial branch blocks
The risks of medial branch blocks are minimal and are similar to any procedure involving a needle placement. These include, but are not limited to:
- Allergic reaction to the anesthetic or contrast dye. Be sure to inform us before the injection if you have any known allergies
- Temporary pain at the injection site
If your procedure includes sedation
- You should have no solid foods for six hours before your procedure.
- You may have clear liquids up to two hours before your procedure. Examples include:
- Clear fruit juices such as apple, cranberry, and grape juice (no pulp)
- Tea, black coffee with no cream
- Carbonated beverages
- Nothing by mouth, including throat lozenges, mints, and all hard candy, for two hours before your procedure.
- No gum for two hours before your procedure.
- You must have a responsible adult arrive with you to our facility and drive you home. If you use a taxi or volunteer ride service, you still must have a responsible adult with you in order to help take care of you after your procedure.
- Please take your regular medications the day of your procedure, especially any heart, diabetes, or blood pressure medications.
Summit Orthopedics offers comprehensive spine expertise
Summit’s spine care team is recognized by the National Committee for Quality Assurance for the comprehensive expertise of our patient-centered care. Our back specialists diagnose spine problems and design custom treatment plans built on a conservative, nonsurgical approach. Most patients find relief through treatments including guided injections, specialized physical therapy, biofeedback, exercise, activity modification, and medication. When conservative care does not relieve symptoms, our highly skilled surgeons offer proven, evidence-based surgical options. Together with you, we will determine the right course of action.
Summit has convenient locations across the Minneapolis-St. Paul metro area, serving Minnesota and western Wisconsin. We have state-of-the-art centers for comprehensive orthopedic care in Eagan, MN, Vadnais Heights, MN, and Woodbury, MN, as well as additional community clinics throughout the metro and southern Minnesota.
More resources for you
- Visit our Spine Exercise Library for options to help ease neck and back pain
- See Summit’s treatment options for neck, back, and spine care
- Check out additional information on Summit’s approach to spine care
Ask the Expert: Spine Video Series
When we have back pain, we want to know why. Dr. Wahlquist explains that this simple question can have a complex answer.
At Summit, injections are one of the conservative treatments offered for back pain. Dr. Santos explains how injections can be used to diagnose, as well as treat, a painful back condition.