Statistical analysis
The study was designed to detect, with 90% power and an overall 5% Type I error rate, a 32 s decrement in operation time and 80 s decrement in radiation-exposure time from 172 s to 106 s, as estimated in the freehand group, based on the pilot in-vitro experiment. Thirty subjects were required for the final analysis.The independent sample t-test, Wilcoxon rank-sum test, Chi-square test, and Fisher’s exact test were used to compare the outcomes between the two groups, where appropriate. All the statistical analyses were performed using the SAS JMP version 16.0 (SAS Institute) software, and statistical significance was defined as 