Anesthesia means loss of sensation or feeling. Certain drugs are given to lessen or stop the pain in part, or all of the body. Regional anesthesia works by numbing a group of nerves that control a section of the body such as an arm or both legs. This type of anesthesia is often used for labor during childbirth, and for surgery or procedures that involve one major part of the body.

When used on the lower half of the body, the patient is numbed all the way from the waist down. This method is sometimes called a spinal or epidural block. Epidural anesthetics are sometimes used for 3 to 4 days after surgery to decrease post-operative pain. For other parts of the body, we can select nerves to block pain.

The patient is not put to sleep by the nerve injection. In some cases, another drug may be given that makes the patient very sleepy and have amnesia for what was done during the procedure.

Depending on where the drug is injected, different side effects may occur. A headache often follows a spinal anesthesia. With both spinal and epidural blocks, the bladder can fill with urine while the person is still numb. A catheter may be required to empty the bladder. Nausea and vomiting may also occur. The numbing effects of the nerve injection wear off in about an hour or two.