Large U.S. corporations also play a major role on the global stage, with more than a fifth of companies on the Fortune Global 500 coming from the United States. Even though the services sector is the main engine of the economy, the U.S. also has an important manufacturing base, which represents roughly 15% of output.
A: Lidocaine is an anesthetic or numbing agent when used topically or injected in the spinal column, and it is an antiarrhythmic (helps with irregular heart beats) when given intravenously. When it is used topically on the skin, it works by inhibiting the nerve impulses that pass along pain signals to the brain.
The doctor uses X-ray guidance to place the injection in the correct nerve. If the procedure relieves the pain, the doctor knows that nerve is the source of the pain and the target for treatment. In some cases, the cervical block is all that is needed. In other cases, its effects wear off. If a cervical block successfully numbed the pain, it is likely that a patient will have a good response to radiofrequency ablation. If it does not, the patient probably is not a good candidate for radiofrequency ablation.