Statistical analysis
All statistical tests and confidence intervals were used in an explorative way, therefore no correction of the type I error (two-sided, 5%) was made except for post-hoc comparisons. All results are therefore descriptive. For all statistical analyses, the open-source statistical computing software R Version 4.1.2 (R Foundation for Statistical Computing, Vienna, Austria. URL Fisher’s exact test (2 × 2 tables) or the exact Chi-Square test (n x k tables) were used for unpaired categorical variables. In the case of two independent groups of ordinal variables the exact Mann–Whitney For assessing the equivalence regarding the outcome “defect closure after 21 days,” an exact two-sided 90% confidence interval for the difference of the proportion of defect closure with an equivalence region of ± 20% was used. The relationship between a metric variable and dichotomous variable was estimated by the point biserial Bravais-Pearson-correlation-coefficient or by the point biserial Spearman-correlation-coefficient (in case of no normal distribution). As test for the correlation coefficient against the reference value zero (no correlation), a test based on the t-distribution was used.