“…Most of the surgical series were retrospective, single-center studies, with the exception of some prospective studies [8,9,29,32,33,48,62,63,67,69,71,73,77] and some multi-institutional collaboration papers [19,24,26,30,38,39,43,45,72] (LOE 4). Only three of the comparative studies were randomized [78][79][80] (LOE 2b); all other comparative studies were nonrandomized, whether prospective or retrospective (LOE 4).…”