Overview of Epidural

Epidural injection is the administration of medication into the epidural space—area outside the dura mater of the spinal cord. It is used to treat swelling, pain, and inflammation associated with neurological conditions that affect nerve roots, such as a herniated disk and radiculopathy.

Epidural injections may be painful and can produce uncertain results. Studies show that epidural injection may provide short-term pain relief for patients when conservative treatments have failed.

Epidural & Anatomy

The brain is covered by three membranes—dura, arachnoid, and pia—called the meninges that extend through the base of the skull and surround the entire spinal cord. The spinal cord travels down the entire length of the spinal column through the spinal canal. The epidural space is located between the dura and the interior surface of the spinal canal and contains veins, arteries, and fat. Epidural injection is the injection of medication into the epidural space.

Epidural Procedure

Epidural injection is usually given in an outpatient setting. The injection often is administered by an anesthesiologist, but some neurosurgeons, orthopedic surgeons, and neurologists are also qualified to perform this procedure.

A mild sedative and a local anesthetic may be used prior to the procedure to relax the patient and numb the injection site. Medications—usually an anesthetic such as bupivacaine (Marcaine) or a muscle relaxant, and a corticosteroid such as methylprednisolone (Medrol)—are injected directly into the epidural space. (The injection is commonly called a cortisone shot.)

Effectiveness of Epidural Injection

Approximately 30 to 70 percent of people who receive an epidural injection benefit from it. Some patients notice improvement within hours of the injection; others improve over a number of days; and others experience no improvement with the treatment. In some cases, two or three injections are given over weeks or months.

Epidural Complications

Complications resulting from an epidural injection are rare. Possible conditions that may develop following the procedure include infection (e.g., epidural abscess), bleeding into the epidural space, and headache caused by a cerebrospinal fluid leak. Approximately 2 percent of patients experience side effects from the corticosteroid, such as mild fluid retention.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 01 Feb 2000

Last Modified: 01 Oct 2015