What Is an Epidural Nerve Block?

What Is an Epidural Nerve Block?

What is an epidural nerve block?

An epidural nerve block is a procedure to block pain by injecting anesthetic medication into the epidural space. The epidural space is the area between the inner wall of the backbone (vertebral column) and the outermost of the three membranes (dura mater) that surround the spinal cord. The space between the inner two membranes (subarachnoid) is filled with cerebrospinal fluid.

The vertebral column is a series of interconnected bones that form a protective covering for the spinal cord. A part of the vertebra called lamina forms a roof over the spinal canal in the back of the spine. The needle is inserted between adjacent laminae to access the epidural space and administer the medication for the epidural nerve block.

The epidural space contains fats to absorb shock, blood vessels and nerve roots. The epidural nerve block numbs sensation by blocking the transmission of pain signals from the nerves to the brain. An epidural nerve block may be administered in the cervical, thoracic, lumbar or the caudal (lowermost) region of the spinal column.

Why is an epidural nerve block performed?

An epidural nerve block is performed as anesthesia during surgeries or for pain relief (analgesia) for short periods or to treat chronic pain syndromes.

Surgical Anesthesia

An epidural nerve block may be performed:

  • As the sole method of anesthesia
  • In combination with spinal anesthesia (anesthetic injected into the subarachnoid space)
  • In combination with general anesthesia

Epidural nerve block is performed for anesthesia in the following situations:

  • Orthopedic surgery on the lower limbs including ankles, knees, hips and pelvic area
  • Vascular surgery (involving blood vessels)
  • Amputation of lower limbs
  • Caesarean delivery of pregnancy
  • Surgery in the lower abdominal area that include:
    • Appendectomy
    • Bladder or kidney surgery
    • Intestinal procedures
    • Hernia repair
    • Prostate surgery
    • Penile procedures
  • Cardiac and other surgeries in the thoracic region
  • Lower body surgeries for children


Epidural nerve block for pain relief may be given as a single injection that lasts up to 24 hours or as a continuous infusion through a flexible tube (catheter) inserted into the epidural space. 

Epidural nerve block is useful in pain relief in the following situations:

  • Prolonged pain relief with a catheter, after a major surgery
  • Pain relief during labor

Epidural injections are used for chronic pain management in the following conditions:

Epidural nerve block is not administered in the presence of certain conditions such as:

  • Depletion of fluid in the blood vessels (hypovolemia) due to salt or water loss
  • Elevated pressure inside the skull (intracranial pressure)
  • Infection at the epidural injection site
  • Allergy to local anesthetic

Epidural nerve block may be avoided in certain conditions:

What are the benefits of an epidural nerve block?

Surgical Anesthesia

  • Improved pain relief post-surgery
  • Less need for opioids
  • Lower incidence of pulmonary complications post-surgery
  • Reduced gastrointestinal complications post-surgery
  • Lower duration of mechanical ventilation
  • Lower risk for deep vein thrombosis
  • Reduced blood loss


  • Lower dosage of medication
  • Longer lasting pain relief
  • Improved quality of life
  • Reduced dependence on opioids


Medically speaking, the term “myalgia” refers to what type of pain? See Answer

Medically Reviewed on 5/29/2020


Medscape Medical Reference