To the Editor

We read with interest the comments by Gizzo et al. [1]. We understand that the interpretation of our composite morbidity indices can become quite difficult without additional in-text explanation of the included indices. We also understand that composite morbidity indices (such as minor and major intraoperative complications) represent the authors’ personal point of view, as other readers might disagree with these classifications. Certain errors, however, were noticed from Gizzo et al. [1] which were corrected and presented in a forthcoming erratum.

Gizzo et al. [1] also commented that we did not consider the data about postoperative pain. In fact in our previous manuscript [2] we specifically tabulated data of visual analogue scale scores that were interpreted by the original studies in mean and standard deviation or median and variance [35]. We excluded two studies from this tabulation because the interpretation of pain scores was different, explaining thoroughly inside our manuscript the actual reasons [6, 7]. Furthermore, we specifically stated inside the main manuscript that in the latter two studies the pain scores were significantly lower among patients operated with an EBVS system. However, in the forthcoming erratum we will provide a meta-analysis of this index, although its interpretation should be assessed with caution as it is based on only three studies [35].