How Can Medial Branch Blocks Help Your Back Pain?

Medial branch blocks have an important place in back pain medicine. According to E-Medicine, several experts believe that problems in the facet joint underlie most cases of mechanical low back pain (possibly 80%). 

A woman rubbing her aching back
Tom Merton / Getty Images

Understanding your anatomy can be helpful in understanding this back pain and its treatment. There are two facet joints in each segment, and together they provide an estimated 36% of the spine's stability for that segment, while at the same time facilitating certain types of movement. Facet joints are also known as the zygapophyseal joints or Z-joints.

The medial nerve lives just outside of and innervates the facet joints. It is also one of three branches of a larger nerve called the dorsal ramus, which is the first subdivided nerve arising from the spinal nerve root. Remember, dorsal means back and ramus means branch.

The three nerves branching from the dorsal ramus serve many areas, including key back muscles. The medial branch in particular affects the facet joint itself as well as deep back muscles such as the interspinales, the multifidus, and a few others. The medial branch also reaches into at least one spinal ligament (the interspinous) and possibly two (the ligamentum flavum as well). 

What Are Medial Branch Blocks?

When you have a medial branch block, a local anesthetic such as lidocaine is injected into the medial nerve of the facet joint. Injecting the local anesthetic into the medial nerve helps healthcare providers diagnose back pain. If the injection relieves at least 50% of your usual back pain, your healthcare provider will likely confirm that the pain is coming from the facet joint and recommend radiofrequency ablation as treatment. Medial branch blocks are also used to diagnose sacroiliac joint pain.

You can have a medial branch block on just one side of the facet joint or on both. When both sides are treated, it is called a bilateral injection.

Medial Branch Blocks or Intra-Articular Injections

Another type of injection used to diagnose back pain is the intra-articular injection. This injection goes right into the facet joint space which is surrounded by a capsule made of tough fibrous tissue. A 2012 study published in the journal Pain Physician found, among other things, that the association between medial branch blocks and successful facet joint treatment may be greater than the one between intra-articular injections and successful treatment. That said, the authors call for additional high-quality studies to be done on the subject before they can confirm this finding.

Medial Branch Blocks as Treatments 

While most of the time the medial branch block is given for diagnostic purposes, it is also sometimes used as a therapy.

A 2013 study published in the Annals of Rehabilitative Medicine found that for people who had medial branch blocks for chronic facet joint pain related to osteoporotic fracture following either vertebroplasty or conservative treatment, the outcomes were good a year post-injection. The authors say that medial branch block yielded pain relief and functional recovery for these patients.

But a 2012 study that evaluated various thoracic facet joint treatments found only fair evidence for medial branch blocks as a way of relieving chronic pain in that area. That said, researchers were not even able to compare medial branch blocks with intra-articular injections, because there was no evidence at all for the intra-articular treatments. And the PM&R study mentioned above aside, only limited evidence was found for radiofrequency neurotomy. The use of radiofrequency ablation and/or neurotomy is more common for facet joint pain treatment than medial branch blocks.

Radiofrequency ablation is an outpatient procedure in which heat is applied to the nerves around the facet joint, killing the cells. Over time, the body replaces the dead nerve cells with scar tissue. Even though radiofrequency ablation is considered a controversial treatment, ablation in lumbar facet joints may provide longer lasting pain relief than in other areas of the spine. A 2015 study published in the International Journal of Anesthetics and Anesthesiology found that two years post lumbar spine radiofrequency ablation, patients were doing well in terms of pain management, ability to function, and how much pain medication they needed.

In a neurotomy, the same type of heat—from radiowaves—is applied in order to temporarily relieve the pain. A 2012 study published in the journal PM&R (Physical Medicine and Rehabilitation) found that pain relief resulting from radiofrequency neurotomy procedures lasted between seven to nine months for most patients, and this was true whether the treated area was in the neck or the low back.

What Happens in a Medial Branch Block?

The procedure will most likely take place in an outpatient facility and you will not be put to sleep. The healthcare provider will start by giving you a shot of a local anesthetic to numb your skin and the tissue near the facet joint. You’ll lie on your stomach to enable the healthcare provider to reach your facet joints, which are located at the back of the spinal column. 

Then the healthcare provider will insert a needle that is hooked up to a camera called a fluoroscope into the facet joint area. Through the needle, contrast dye will be injected into the area. This enables the healthcare provider to see whether or not the numbing agent to be used covers the entire area around the facet joint. Next, the anesthetic is injected into the joint. 

Once the anesthetic has been injected, your healthcare provider may direct you to perform the same moves that normally bring on your pain or symptoms. According to Alex Vaccaro, MD, professor of neurosurgery and orthopedic surgery at Thomas Jefferson University in Philadelphia and co-director of their Spinal Cord Injury Center, between 50% and 75% pain relief will give your healthcare provider a reason to confirm that your back pain is coming from your facet joint and/or your medial branch nerve.

Because each facet joint is supplied by two medial branch nerves (one from the vertebra above and one from the vertebra below) you’ll likely receive two shots of anesthetic for every facet joint marked for treatment.

This can make for confusion when it comes to medical coding and billing. In fact, in recent years, facet joint injection documentation problems have led to a substantial degree of Medicare fraud.

Medicare Fraud and Abuse Relating to Facet Injections

A 2008 report issued by the Health and Human Services Office of Inspector General found a 76% increase in Medicare payments for facet blocks between the years of 2003 and 2006. The authors found that of these, 63% of the injection services were poorly documented, incorrectly coded (82% of these resulted in Medicare overpayments) and/or not medically necessary. 

In 2006, Medicare paid out $81 million for physician services that were either not well documented or not documented at all. The report states that while some of these inappropriate payments were based on documentation errors, others may well have been for injections that never even happened. According to the report, most of the time, the healthcare providers at least submitted a patient record to Medicare, but in some instances, they didn’t even do that and they still got paid.

Some of the errors in the records submitted to Medicare included missing descriptions of the procedure done or missing details, for example, an identification of the spinal level and/or side of the back (i.e. right, left or both) that received the injection.

Billing add-on codes that were supposed to indicate bilateral injections (i.e. the shot on both sides of your facet joint) resulted in 50% more payments than Medicare should have allowed, the report says. The authors of the report say that while some of these errors were probably accidental, others were likely instances of intentional fraud.

The report also said that healthcare providers in outpatient facilities were more likely to make such errors and/or commit fraud than those who practiced in hospitals. The comparison was 71% of facet injection services provided in an office to 51% for those given in a facility such as a hospital.

Perhaps the worst offenses, though, were those injections given that were not medically necessary. According to the report, the tally for this version of medical fraud was $17 million.

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Spine Health. Medial branch nerve blocks.

  2. Manchikanti KN, Atluri S, Singh V, Geffert S, Sehgal N, Falco FJ. An update of evaluation of therapeutic thoracic facet joint interventions. Pain Physician. 2012;15(4):E463-81.

  3. Park KD, Jee H, Nam HS, et al. Effect of medial branch block in chronic facet joint pain for osteoporotic compression fracture: one year retrospective study. Ann Rehabil Med. 2013;37(2):191-201. doi:10.5535/arm.2013.37.2.191

  4. Smuck M, Crisostomo RA, Trivedi K, Agrawal D. Success of initial and repeated medial branch neurotomy for zygapophysial joint pain: a systematic review. PM R. 2012;4(9):686-92. doi:10.1016/j.pmrj.2012.06.007

  5. Cleveland Clinic. Radiofrequency ablation.

  6. Mccormick ZL, Marshall B, Walker J, Mccarthy R, Walega DR. Long-term function, pain and medication use outcomes of badiofrequency ablation for lumbar facet syndrome. Int J Anesth Anesth. 2015;2(2).

  7. Smuck M, Crisostomo RA, Trivedi K, Agrawal D. Success of initial and repeated medial branch neurotomy for zygapophysial joint pain: a systematic review. PM R. 2012;4(9):686-92. doi:10.1016/j.pmrj.2012.06.007

  8. Panorama Orthopedics & Spine Center. Medial branch block information sheet.

  9. Department of Health and Human Services Office of Inspector General. Medicare payments for facet joint injection services.

Additional Reading