Epidural and spinal blocks are types of anesthesia in which a local anesthetic is injected near the spinal cord and nerve roots. It blocks pain from an entire region of the body, such as the belly, the hips, the legs, or the pelvis. Epidural and spinal anesthesia are used mainly for surgery of the lower belly and the legs. Epidural anesthesia is often 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. The catheter 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. But 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 they may be injected into the epidural space along with the local anesthetic.
You are monitored closely when receiving epidural or spinal anesthesia. That's because the anesthetics can affect the central nervous system, cardiovascular system, and respiratory system. Both spinal and epidural anesthesia may affect blood pressure, breathing, heartbeat, and other vital functions.