2.3.1. Sample Size
To hypothesis that the effect of the 800 mg ibuprofen group was better than the placebo group, and the study design was 1 : 1, when the main efficacy point was the total dose of morphine 24 h after surgery. The parameters were set: bilateral Percentages present categorical variables. Interquartile range presents level variable. If the continuous variables conformed to a normal distribution, parametric tests, such as one-way analysis of variance (ANOVA), were used, and the results were expressed as means ± standard deviation (SD); if they did not conform to a normal distribution, nonparametric tests, such as rank sum tests, were used, and the results were expressed as median and interquartile range. Therefore, ANOVA and the LSD test were used to compare different groups' continuous variables (VAS scores, the AUC of VAS, and the cumulative morphine dose). Laboratory assessments were analyzed using paired 