Has your doctor recommended medial branch block to deal with back pain? If so, you are in good company. Medial branch blocks have been a popular diagnostic tool among pain medicine doctors for a long time. They can go a long way toward alleviating back pain.

What you might not know is that the procedure actually requires two injections. This is not your doctor attempting to double-dip. Two injections are required because of human biology. If the doctor had only numbed a single nerve, your pain would continue and you would essentially fail the test. Two nerves need to be blocked in order to use the test successfully.

A Nerve Block for Diagnostic Purposes

The first thing to note about medial branch blocks is that they aren’t intended to be curative. In other words, the procedure is not designed to provide long-term pain relief. In fact, pain relief tends to wear off within a couple of hours. So what’s the point? Medial branch blocks are a diagnostic tool.

Texas-based Lone Star Pain Medicine explains that the medial branch block is often used to diagnose facet joint syndrome. This is a syndrome in which one or more of the facet joints in the back becomes inflamed or otherwise irritated. Stiffness and pain are a normal result.

One of the big challenges of treating facet joint syndrome is identifying the exact joints causing the problem. This is where the medial branch block becomes very helpful. By blocking the nerves associated with a suspected joint, a doctor can determine whether that joint is the true source of a patient’s pain. If the block works, the doctor has diagnosed correctly. If not, he has to look at other joints as possible causes.

Your Nerves Have Backups

The medial branch nerve block is an injection therapy. The doctor injects an anesthetic into the targeted area in hopes of numbing the pain by blocking pain signals so they do not reach the brain. But here is the thing: the nerves in your back have a built-in backup system. So when a doctor administers the nerve block, they have to numb both the primary nerve and its backup.

One of the nerves drops down from the spinal cord just above the affected joint. The other nerve sits at the same level as the joint. If a doctor numbed just one of these nerves, the other would take over the entire load completely. The patient’s pain would continue unabated. But blocking both nerves guarantees no pain signals will reach the brain.

Getting It Right Matters

Getting it right matters to both the doctor and the patient. From the doctor’s perspective, positively verifying the source of a patient’s pain is the first step in relieving it. From the patient’s perspective, no procedure is worthwhile if it doesn’t yield accurate results.

To ensure the success of the procedure, most pain medicine doctors will use fluoroscopy to guide their needles. Fluoroscopy is a form of X-ray that allows a doctor to see exactly where his needle is going upon insertion. Making sure he is inserting it into the right location guarantees that the correct nerves are being bathed with anesthetic.

Results Determine Treatment Direction

The results of the block determine treatment direction moving forward. If the block proves successful, the doctor has identified the correct joint or joints and can recommend a more permanent treatment. Otherwise, the doctor must look at different joints or consider a separate root cause of the patient’s pain altogether.

Either way, two injections are needed to complete the medial branch block. And now you know why.