An epidural is an injection that delivers medication directly into the epidural space in your spine. The epidural space surrounds the spinal cord and spinal nerves. Epidural injections are used to treat radicular pain caused by nerve irritation. This type of pain is usually caused by herniated discs or spinal stenosis. The injections can provide relief for weeks to months, and may allow the patient to participate in more aggressive rehabilitation. In some cases, they may enable the patient to postpone or avoid surgical treatment altogether.