Statistical analysis
Categorical variables were reported as counts and percentages, while continuous variables were reported as medians and interquartile ranges (IQRs). Fisher’s exact test was used to compare categorical variables between the groups, and the Mann − Whitney U test was used to compare continuous variables between the groups.Equivalence tests with two one-sided tests (TOST) were performed to examine the success rate difference and the median difference of the time required for success between the top-down manoeuvre and bottom-up manoeuvre. In the TOST, equivalency is determined when the 90% confidence interval (CI) of the success rate difference or the median difference of the time required for success is within a predetermined equivalence margin [