What is a medial branch nerve?
The medial branch nerves are small nerves that come out from the facet joints in the spine. They are responsible for carrying pain signals from the facet joints to the brain. As time passes, the facet joints start to deteriorate and become inflamed. When this happens the medial branch nerves sends pain signals to the brain.
Explanation of a Medial Branch Block
1. Anatomy & Rationale:
- The facet joints are the small joints located between and behind adjacent vertebrae. They provide stability and allow for movement between the spinal bones.
- Each facet joint is innervated by the medial branch nerves, which transmit pain signals from the facet joints to the brain.
- If it’s suspected that the facet joints are a source of pain, a medial branch block can be used to temporarily block the pain signal and help identify the problematic joint(s).
2. Procedure Process:
- Preparation: The patient lies face down on a procedure table. The skin over the area to be treated is cleaned and sterilized. Local anesthesia is applied to numb the skin.
- Guidance: Using fluoroscopy (live X-ray) for guidance, the physician advances a fine needle towards the medial branch nerves that correspond to the suspected painful facet joints.
- Injection: Once the needle is in the correct location, a small amount of contrast dye is injected to ensure proper needle placement. Then, a mixture of a local anesthetic (like lidocaine or bupivacaine) and sometimes a corticosteroid is injected near the nerve.
3. Diagnostic Purpose:
- If the patient’s pain diminishes significantly (usually by 50% or more) after the injection, it suggests that the facet joint(s) innervated by the blocked medial branch nerves are the source of the pain.
- It’s important to note that the pain relief from a medial branch block is temporary. The duration of relief can vary from hours to days.
4. Subsequent Procedures:
- If a medial branch block is successful in identifying the source of pain, a more permanent procedure called radiofrequency ablation (or medial branch rhizotomy) may be considered. This procedure uses heat to disrupt the medial branch nerve’s ability to transmit pain signals from the facet joint.
5. Risks & Complications: While medial branch blocks are generally safe, like any medical procedure, they carry some risks. These might include bleeding, infection, increased pain, or allergic reactions to the medications used. However, when performed by experienced professionals, complications are rare.
6. Conclusion: A medial branch block is a valuable diagnostic tool in the realm of pain management. It aids physicians in pinpointing the source of spinal pain and can guide further therapeutic interventions.
It’s essential for patients to discuss their symptoms, medical history, and any potential risks or concerns with their physician before undergoing the procedure.
