A medial branch block is a quick, X-ray–guided injection that numbs the tiny nerves carrying pain from the facet joints. It is the most reliable way to confirm whether facet joints are the true source of your lower back pain — and it guides the next steps in care.
What Are Medial Branch Nerves?
Each facet joint gets its feeling from tiny nerve branches called medial branches. When a facet joint becomes arthritic or inflamed, those nerves send pain signals to the brain. Blocking them temporarily tells us whether those joints are driving your symptoms.
What the Procedure Is Like
Using X-ray guidance, a small amount of numbing medicine is placed precisely on these nerves. You go home the same day and simply pay attention to your pain over the next hours. Dramatic relief — even briefly — tells us the facet joints are the culprit. Sometimes we repeat the block once more to be certain before moving ahead.
What Happens After a Positive Block?
When a medial branch block confirms facet pain, the usual next step is radiofrequency ablation (RFA) — a longer-lasting treatment that quiets those same small nerve branches. Other options on the treatment ladder include endoscopic rhizotomy, peripheral nerve stimulation, and, in select cases, supportive devices or fusion for true structural problems.
Related Care
- Facetogenic Back Pain: Causes, Symptoms & Treatment Options
- Radiofrequency Ablation (RFA)
- Endoscopic Spine Surgery
- Back Pain video series
This page is for general education only and is not a substitute for professional medical advice, diagnosis, or treatment. Please consult a qualified physician about your specific condition.