Nerve root pain is also called radiculopathy and usually results from a herniated disc. It starts in the low back, goes down the leg, below the knee and often aggravated by bending forward, with some patients experiencing weakness and/or decreased reflexes.

Nerve root injections may avoid the need for surgery, if pain is successfully reduced, and enable progress to a therapeutic exercise programme. The image-guided injections work by inhibiting prostaglandin synthesis, inhibition of phospholipase A2, nerve membrane stabilization, and blocking C-fibre conduction.

The most common injection that is performed is an epidural steroid injection. It is most commonly used for either nerve root generated pain or discogenic pain, i.e., pain from the outer portion of the disc, called the annulus fibrosis.