Statistical analysis
Statistical analysis was performed using SPSS (SPSS Inc. Released in 2009, PASW Statistics for Windows, Version 18.0. Chicago). Two-way repeated measures of ANOVA were used to assess variables associated with postoperative patient satisfaction. Mann-Whitney U test and Wilcoxon singed rank test were used to compare pre- and post-MR sialography. The null hypotheses of no difference were rejected if P values were less than 0.05 or equivalently if the 95% confidence intervals (CIs) of risk point estimates were excluded.