The radiofrequency instrument sends out high-frequency radiofrequency current, which causes the ion movement in the target tissue to generate heat and thermal coagulation to destroy the tissue and nerve in the target area. Highly selective destruction of nociceptive nerve fiber conduction branch, blocking pain signals to the superior nerve conduction, destruction of pain transmission pathway, so that it can not be transmitted to the brain, can not produce pain sensation and experience, so as to achieve the purpose of pain control. The nerve fibers that manage nociceptive conduction in human body are unmyelinated fine fibers (Aδ, C) with thin diameter (2~4μm), which usually degenerate at 70℃~75℃, while the nerve fibers that manage motor and tactile conduction are myelinated thick fibers (Aβ) with thicker diameter (8~14μm), which can tolerate higher temperature. Radiofrequency thermocoagulation technique is a clever way to take advantage of this difference in temperature tolerance of different nerve fibers and selectively block the Aδ and C fibers that conduct nociceptive sensation to achieve both pain relief and preservation of local tactile sensation.