Patients in the preoperative group reported lower pain Numeric Ranking Scale values compared with those in the control group ( net difference 2 points ; 95 % confidence interval [ CI ] , 0.3-3 .1 at 4 hours , 1-3 at 6 hours , and 0.7-3 at 24 hours ; p = .01 ) Patients in the preoperative group consumed significantly less morphine than did those in the control group ( net difference 7 mg ; 95 % CI , 0.7-13 ; p = .02 ) .