Statistical analysis
Clinical data were expressed as absolute and percentage frequency and analyzed using Fisher's exact test or Pearson's chi-square test. Surgical times were expressed as mean and standard deviation, submitted to the Shapiro–Wilk normality test and analyzed using the Mann–Whitney or Kruskal–Wallis tests. The analyzes were performed using the SPSS software, version 20.0 for Windows, adopting a 95% confidence level.