The purposes of nerve block therapy are as follows: (1) therapeutic nerve block: to eliminate pain and improve blood flow through nerve block to achieve therapeutic purposes; (2) diagnostic nerve block: to diagnose the disappearance of pain according to the situation of pain after blocking the intrinsic nerves or segmental crural nerves; (3) nerve block used to determine the prognosis. Characteristics of nerve block therapy: (1) the analgesic effect is really reliable; (2) it is of great significance to the diagnosis of the disease; (3) the therapeutic range and the time can be selective; (4) it doesn’t need special equipment and devices; (5) it has little side effects; (6) the therapeutic effect is closely related to the operation skill.