After 3 treatment , pain intensity on NRS decreased compared with Baseline ( -1.67 , 95 % confidence interval [ CI ] -1.46 to-1 .87 ) in the electroacupuncture group ; there was little change ( -0.13 , 95 % CI 0.08 to-0 .35 ) in control group ; the difference between two groups was statistically significant ( P < 0.001 ) .