Neuraxial anesthesia works by delivering local anesthetics near the spinal cord, blocking the conduction of nerve signals. These anesthetics inhibit the electrical impulses that transmit sensory and motor signals between the body and the brain. As a result, patients experience a temporary loss of sensation and motor control below the injection site, making these techniques ideal for surgeries involving the lower body, pelvis, and abdomen.
In spinal anesthesia, the anesthetic is injected into the CSF within the subarachnoid space, allowing the medication to rapidly surround the spinal nerve roots. This creates an almost immediate and profound block, typically affecting multiple dermatomes below the injection site. The effect lasts for several hours, depending on the drug and dosage used, and often leads to complete paralysis of the lower extremities during the procedure.
Epidural anesthesia, on the other hand, involves the injection of local anesthetics into the epidural space. The anesthetic spreads around the nerve roots and along the spinal column, producing a broader and more variable block. The degree of anesthesia depends on factors such as the volume and concentration of the anesthetic and the injection site. The onset of epidural anesthesia is slower than spinal anesthesia, taking about 10 to 20 minutes to take effect. Additionally, the anesthetic may be absorbed into the bloodstream, affecting both the duration and intensity of the anesthesia.
