From T0 to T7, to achieve similar VAS pain relief, group 1 had the number of pain rescues (1.86 ± 0.72 times) and total drug intake (67.91 ± 9.87mcg) is lower than group 2 (with p < 0.01) with the corresponding data of 5.63 ± 1.45 times and 75.75 ± 14.06mcg.