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.
If you look at an adult foot from the inside, you'll usually notice an upward curve in the middle. This is called an arch. Tendons -- tight bands that attach at the heel and foot bones -- form the arch. Several tendons in your foot and lower leg work together to form the arches in your foot.
When the tendons all pull the proper amount, then your foot forms a moderate, normal arch. When tendons do not pull together properly, there is little or no arch. This is called flat foot or fallen arch.
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.