Epidural anesthesiacomprises of the insertion of a hollow needle and a small, flexible catheter in the space between the spinal column and outer membrane of the spinal cord (epidural space) in the middle or lower back. The part 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 the catheter remains in its place. The anesthetic medicine is injected into the catheter to paralyze the body above and below the point of injection as needed. The catheter is secured on the back so that it can be used repeatedly if more medicine is needed.
Spinal anesthesia is done on a very similar pattern. But the anesthetic medicine is injected using a much smaller needle, directly into the cerebrospinal fluid that encloses the spinal cord. The area where the needle will be inserted is first numbed with a local anesthetic and then the needle is guided into the spinal canal, and the anesthetic is injected at the desired place. It is generally done without the use of a catheter. Spinal anesthesia numbs the body below and sometimes above the site of the injection. The person may not be able to move his or her legs until the anesthesia effect.
Epidural and spinal anesthesia are usually combined with other medicines that make you relaxed or sleepy or relieve from pain. These other medicines are often given through a vein or they may be injected into the epidural space along with the local anesthetic.