Statistical Analysis
The coding and statistical analysis of the data were done on the
computer, using the SPSS 22 software (IBM SPSS Statistics, IBM
Corporation, Chicago, IL) package. Descriptive statistical data for
continuous variables were expressed in terms of the mean and median,
whereas categorical variables were expressed in terms of frequency and
percentages. Receiver operating characteristic curves (ROCs) were
created to evaluate the predictive role of the modified S-ReCS, RUSS,
and R.I.R.S scoring systems in terms of residual stone presence and
postoperative infective complication rates. Univariate and multivariate
logistic regression models were used to identify risk factors for
residual stones and postoperative infective complications. The
statistical significance level was accepted as 0.05 in all analyses.