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, but it can also be used to help control pain after major surgery to the belly or chest.
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. The area where the needle will be inserted is first numbed with a
local anesthetic. Then the needle is guided into the spinal canal, and the
anesthetic is injected. This is usually 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 anesthetic wears off.
A headache is the most common side effect of spinal anesthesia. It can usually be treated easily. Headaches are less common with epidural 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 blood pressure, breathing, heartbeat, and other vital functions.