Selective Nerve Root Block for Back Pain Management

Back PainA selective nerve root block is a type of injection used to alleviate back pain and radiculopathy symptoms. Along the spine, there are several foramina (holes) through which the spinal nerves emerge from the spinal cord. When these foramina are partially closed due to arthritic bone spurs, bulging discs, or misalignment of the vertebrae, the nerve roots may also become pinched. An injection of a corticosteroid agent will alleviate nerve root inflammation.

What conditions are treated with a selective nerve root block?

Anything that causes nerve root irritation or inflammation can be treated with a selective nerve root block. Nerve compression leads to radiculopathy, which involves radiating, shooting pain down an extremity along with weakness and numbness. Conditions known to be associated with radiculopathy include bulging cervical or lumbar discs, spinal stenosis, spinal arthritis with bone spurs, herniated discs, and spondylolisthesis.

How common is chronic low back pain?

In the U.S., chronic low back pain is the most common cause of disability among persons aged 45 years and younger. Chronic low back pain affects around 5% of the general population, and every year, 1% of the working-age population becomes permanently disabled, some due to back pain.

Why is the selective nerve root block done?

When nerves are pinched, irritated, or inflamed by a narrowed nerve canal, bone spur, or bulging disc, the resulting inflammation causes pain, tingling, and numbness. Injecting an anesthetic and/or steroidal agent onto the nerve can remove irritating chemicals, reduce swelling, and alleviate pain.

How long does the procedure take?

The actual injection only takes around 10 minutes. However, expect to be at the medical facility for 45-75 minutes for patient sign-in, signing informed consent, receiving a sedative, and observation in the recovery room following the injection.

Will the nerve root block hurt?

All procedures begin with injecting the skin and deeper tissues with a local anesthetic through a small needle. You will feel a slight pinch following by mild burning that last a few seconds. Once the skin is numb, you will only feel pressure at the injection site. If the needle brushes against the nerve, you may feel a tingling or mild electric shock sensation, but there is no pain. After the injection, the site will be numb for 30-90 minutes, then soreness occurs. However, soreness improves gradually and only lasts around 12-24 hours.

Will I be put to sleep for the nerve root block procedure?

The procedure is done using local anesthesia and a mild sedative. Some patients dose off during the procedure, but you are not unconscious.

How is a selective nerve root block done?

After being positioned on your stomach, the site is cleaned using an antiseptic. The skin is numbed with the anesthetic, and the procedure needle is inserted using x-ray guidance for correct placement. After position is verified, the medication is injected onto the nerve, and the needle is removed.

How many injections are needed?

The effectiveness of the block varies from person-to-person, and is typically 2-8 months. The anesthetic offers immediate pain relief, and the steroid begins working in 1-2 days. Some people only require one injection, but a patient can have several injections spaced 2 months apart.

Does the selective nerve root block work?

According to a recent study, 86% of patients reported pain relief after the selective nerve root block. The researchers concluded that the selective nerve root block is effective in treating back pain and sciatica.


Pfirrman CW, Oberholzer PA, Zanetti M, et al. (2001). Selective nerve root blocks for the treatment of sciatica: evaluation of injection site and effectiveness–a study with patients and cadavers. Radiology, 221(3), 704-711.