Statistical methods
SECONDARY
The normality of continuous data is to be checked using the Shapiro–Wilk test and histogram. Continuous data are to be summarized as the mean ± standard deviation, median, or interquantile range (IQR). Analysis of the primary and secondary outcomes is to be based on the intention-to-treat (ITT) and per-protocol (PP) analyses, and missing data will be imputed by multiple imputation or other appropriate methods. In the ITT analysis, participants are evaluated on the basis of the group to which they were randomly assigned, regardless of whether they actually received the surgery. In the PP analysis, participants are evaluated on the basis of the group to which they actually received the surgery to truly reflect the difference between the two groups. Paired A two-sided 