“…Thirteen studies were performed retrospectively [10,11,16,17,19,20,24,[27][28][29][30][31][32], 9 studies [8, 12-14, 22, 23, 33-35] were retrospective evaluations of prospectively collected data and the remaining 9 studies were prospective [9,15,21,25,26,[36][37][38]. Fifteen of the studies (50%) analysed the learning curve corresponding to a single surgeon [8,11,13,16,17,21,22,24,26,27,29,33,35,38,39].…”