The selective nerve root block (SNRB) is another common injection used to relief of low back pain and/or leg pain, but mostly it used to diagnose the specific source of nerve root pain.

SNRB is approached the nerve at the level where it exits between the vertebral bodies. It done with using flouroscopy (live x-ray) to ensure the right medication delivery. If the patient’s pain goes away after the injection, it can be inferred that the pain generator is the specific nerve root that has just been injected and the steroid also helps reduce inflammation around the nerve root.

Since the SNRB injection is outside the spine, there is no as much risk as in epidural or facet joint injections. However, since the injection is right next to the nerve root, uncommonly the SNRB will temporarily worsen the patient’s leg pain.