Epidural injections are often used to treat radicular pain, also called sciatica , which is pain that radiates from the site of a pinched nerve in the low back to the area of the body aligned with that nerve, such as the back of the leg or into the foot. Inflammatory chemicals (. substance P, PLA2, arachidonic acid, TNF-α, IL-1, and prostaglandin E2) and immunologic mediators can generate pain and are associated with common back problems such as lumbar disc herniation or facet joint arthritis . These conditions, as well as many others, provoke inflammation that in turn can cause significant nerve root irritation and swelling.
An epidural steroid injection (ESI) is a common way to treat inflammation associated with back pain, as well as related pain in the neck, legs, or arms. Spinal nerves may become inflamed due to narrowing of the passages where nerves travel as they pass down or out of the spine. An epidural procedure delivers powerful anti-inflammatory medicine directly into the space outside the spinal sac of fluid around the spinal cord. This area is called the epidural space. An ESI is not the same as epidural anesthesia given just before childbirth or certain types of surgery.