Dear Editor,

I have read with interest the study by Maak et al., which suggests that there is no relationship between the depth of the gluteal fold (IGF) and pilonidal sinus disease (PSD), contrary to previous information (1). The authors made measurements at five points in the sacroperinal region. The data of 105 normal individuals and 95 patients with PSD were measured at five points. I think that there are some shortcomings in the selection of statistical methods and the provision of the necessary data. The authors used the Analysis of Variance (ANOVA) to compare the IGF depth between the two groups (PSD and non-PSD). ANOVA is not suitable for comparing PSD and non-PSD groups because ANOVA is designed for three or more groups. In contrast, this comparison includes only two groups (PSD and non-PSD). For each anatomical measurement (a, b, c, d, e), a pairwise comparison of PSD vs. non-PSD using a t-test at each point would be clearer and statistically appropriate. Inclusion of error bars on Figure 2 will also help readers to better visualize the distribution of IGF in both patients and the population. The mean and standard deviation measurements (if the groups are normally distributed according to the test of normality), containing the p-values for each anatomical measurement for both groups, should be mentioned. Unfortunately, these data are missing, but they are the main point of this article. I would like to thank the authors for their valuable work.