Epidural and spinal blocks are types of anesthesia in which a local anesthetic is injected near the spinal cord and nerve roots to block sensations of pain from an entire region of the body, such as the abdomen, the hips, the legs, or the pelvis. Epidural and spinal anesthesia are used primarily for surgery of the lower abdomen and the legs. Epidural anesthesia is frequently used in childbirth.

Epidural anesthesia involves the insertion of a hollow needle and a small, flexible catheter into the space between the spinal column and outer membrane of the spinal cord (epidural space) in the middle or lower back. The area where the needle will be inserted is numbed with a local anesthetic. Then the needle is inserted and removed after the catheter has passed through it and remains in place. The anesthetic medicine is injected into the catheter to numb the body above and below the point of injection as needed. The catheter is secured on the back so it can be used again if more medicine is needed.

Spinal anesthesia is done in a similar way, except the anesthetic medicine is injected using a much smaller needle, directly into the cerebrospinal fluid that surrounds the spinal cord. This is often done without the use of a catheter. Spinal anesthesia numbs the body below the site of the injection or above it also. This depends on the anesthetic dose and the technique used to give it. A spinal catheter may be inserted and left in place for continuous spinal anesthesia.

Epidural and spinal anesthesia are usually combined with other medicines that make you relaxed or sleepy (sedatives) or relieve pain (analgesics). These other medicines are often given through a vein (intravenously, IV) or may be injected into the epidural space along with the local anesthetic.

You are monitored carefully when receiving epidural or spinal anesthesia because the anesthetics can affect the central nervous system, cardiovascular system, and respiratory system. Both spinal and epidural anesthesia may significantly affect breathing, heartbeat, and other vital functions.