A selective nerve root block (SNRB) is a diagnostic test your doctor performs to determine if a specific spinal nerve root is the source of neck or back pain. Depending on where you feel pain, your doctor may perform one or more diagnostic injections in your cervical (neck) or lumbar (low back) spine.
If the SNRB reduces your pain and related symptoms, then that particular nerve or nerves are identified as a pain source.
Selective nerve root block…
- Provides important diagnostic information to your doctor; gives evidence that a particular nerve root is causing pain
- May relieve pain and nerve related symptoms
The location of the spinal cord, nerve roots and neuroforamen is illustrated (below). The neuroforamen are nerve passageways naturally created by surrounding bones.
Your doctor reviews all the medications, vitamins and herbal supplements you take. Certain drugs (e.g., blood thinners), such as NSAIDs (non-steroidal anti-inflammatory drugs) and supplements should be stopped several days before your procedure. If you are taking an anti-inflammatory medication, your doctor may ask you to stop taking the NSAID, so he can accurately assess the effectiveness of the selective nerve root block and reduce the risk of bleeding.
Possible risks of a nerve block
All medical procedures are inherent for risk. Rare but serious complications include bleeding, infection, nerve injury, headache, and allergic reaction to medication. Other risks include increased pain or injection site tenderness. Your doctor thoroughly discusses your personal risks with you before the procedure.
How a nerve block is performed
A selective nerve root block is performed in a sterile setting, such as an operating room or ambulatory surgery center suite. You change into a gown. An intravenous line is started, and medication is administered through the IV to keep you comfortable. You may be awake or in a twilight state.
In the surgical suite, you are positioned to give the doctor access to either your neck or low back. The skin area is cleansed using a sterile soap. A local anesthetic is injected to numb the area. A special imaging machine called a C-arm (fluoroscopy) is positioned to enable your doctor to view your spine during the procedure. The needle is advanced just outside the neuroforamen adjacent to the suspect nerve root. A small amount of contrast (dye) is injected to confirm needle placement and material flow. Your doctor may ask you to describe what you feel. Next, the lidocaine is injected into the area. Lidocaine is a local anesthetic. A corticosteroid may be added. A corticosteroid is a slow-releasing and long-lasting anti-inflammatory medication that effectively reduces inflammation. As the medication is injected, it flows around and coats local nerve roots.
After a selective nerve root block
The procedure takes about 15-minutes but may take longer if more than one injection is performed. A small bandage covers the entry point of the needle. You are moved into a recovery area and closely monitored before being discharged home with written aftercare instructions. We call you the day after your procedure to follow up.
Keep a pain diary
You may experience some discomfort for a few days after the procedure. This is normal. We ask you to record your pain levels and other symptoms after the procedure. Your pain diary helps your doctor fine-tune your treatment plan.
Learn more about SNRB from these online sources: