How Epidural Nerve Blocks Work


What is an epidural injection?

Epidural injections consist of delivery of medicine into the epidural space via a syringe. The epidural space is the fat-filled area covering the spinal cord. It protects the spinal cord and surrounding nerves from damage. Many people confuse an epidural anesthesia injection, widely known to relieve pain as women are giving birth, with an epidural steroid injection.

An epidural is commonly referred to as the following:

  • Epidural anesthesia
  • Epidural block
  • Epidural steroid injection (ESI)
  • Regional anesthesia
  • Neuraxial anesthesia

How does an epidural nerve block work?

An epidural nerve block is one of the most common uses of an epidural. It involves anesthetic medicine being injected into the epidural space around the spine. The medicine blocks pain signals that travel from the spine to the brain. They typically begin to work in 10 to 20 minutes.

The spinal cord connects nerves throughout the body to the brain. For example, a foot injury sends a pain signal to the spinal cord, which then sends the signal to the brain and back into the foot. An epidural anesthetic can temporarily numb spinal nerves, which, in turn, blocks pain signals.

Temporary pain relief or temporary lack of feeling can be experienced. How much feeling is temporarily lost depends on the following:

  • Type of anesthetic medicine used
  • The concentration of the medicine
  • The dosage

Epidural steroid injection

An epidural steroid injection (ESI) is also used as a management tool for chronic pain; however, it works slightly differently. A steroid medication is used instead of anesthetic medicine. The steroid coats the affected nerve to reduce swelling. This allows the nerve time to heal and can possibly provide long-term or permanent pain relief.