Selective Nerve Root Block

A selective nerve root block (SNRB) places numbing medicine, often with a steroid, right next to one specific spinal nerve where it exits the spine. It is similar to a transforaminal epidural injection, but it is aimed precisely at a single nerve.

It has two jobs: it can relieve pain, and it can pinpoint which nerve is causing your symptoms. If your usual pain goes away when one nerve is numbed, that nerve is very likely the source.

These injections are usually performed by a pain management specialist or interventional physician. Dr. Grunch works closely with trusted pain management specialists and will refer you when an injection is a good next step, either to treat your pain or to help confirm where it is coming from.

• People with arm or leg pain when imaging shows more than one level that could be the cause
• Patients being planned for surgery, to confirm which level to treat
• People with foraminal stenosis, herniated discs or adjacent segment disease
• Patients with pain after prior spine surgery

• Ask about blood thinners. If you take a blood thinner such as warfarin, apixaban (Eliquis), rivaroxaban (Xarelto), clopidogrel (Plavix) or daily aspirin, tell the doctor doing the injection. Some injections require stopping it for a few days and some do not. Never stop a blood thinner on your own; the doctor who prescribes it will tell you if and when it is safe.
• If you have diabetes, check your blood sugar more often for a few days afterward, because steroid medicine can raise it.
• Tell the team about any allergies, especially to contrast dye, iodine, latex or numbing medicine.
• Reschedule if you have a fever or an infection, or if you might be pregnant.
• Arrange for a driver if you will be given medicine to relax. Many people choose to bring a driver either way.
• Come with your usual pain if possible. Do not take extra pain medicine that morning unless instructed, so the test can tell whether the block relieves your pain.

You will lie on a table, usually face down. The skin is cleaned and numbed. Using live X-ray (fluoroscopy) or sometimes ultrasound, the doctor guides a thin needle to the exact spot. A small amount of contrast dye is often used to confirm the needle position before the medicine is injected. You may feel pressure or a brief, familiar pain. The injection itself usually takes 10 to 30 minutes.

Pay close attention to your pain for the first several hours. You may be given a pain diary to record how much your usual pain improves, because that answer guides your treatment. The steroid, if used, may give longer relief that starts within a few days.

Selective nerve root blocks are generally safe. Possible side effects include temporary numbness or weakness in the arm or leg, soreness, a rise in blood sugar and, rarely, infection, bleeding or nerve injury.

What is the difference between a nerve root block and an epidural?

Both deliver medicine near the spinal nerves. A selective nerve root block targets one specific nerve, so it can also show which nerve is causing the pain.

Why would I need a nerve root block before surgery?

When an MRI shows several possible problem levels, the block helps confirm which one is causing your pain, so surgery targets the right spot.

Is temporary numbness normal?

Yes. The arm or leg may feel numb or heavy for a few hours while the numbing medicine wears off. Have someone drive you home.

If you have neck pain, back pain or nerve pain and want to know which treatments make sense for you, call 470-293-9800 or contact us to schedule a visit with Dr. Grunch or one of her physician assistants. You can also ask general questions any time through our “Ask Us Anything” chat.

Related: All non-surgical treatment options · Epidural steroid injection · Foraminal stenosis

This information is for educational purposes only and is not medical advice. It does not replace individualized care from a licensed physician. Please talk to your provider about your symptoms and treatment options.