1.Visual analogue scales (VAS) is the most commonly used method to quantify the degree of pain in clinical practice. In other words, a straight line of l0cm length is drawn on the paper and the ends are marked with “0” and “10” respectively. “.” represents no pain and “10” represents the most severe pain. The distance from the starting point to the marked point (expressed in cm) is the rating value. The higher the score, the more severe the pain is. 2.Verbal rating scale (VRS) The patient describes the pain state he/she feels, and generally the pain is divided into four levels: ① no pain; ② slight pain; ③ moderate pain; ④ severe pain. Each level is scored 1 point, for example, “severe pain”, the score is 4 points. This method is simple and easy for patients to understand, but it is not precise enough.