“…Among them, 5 studies was non-RCT, [9,11,13–15] and 7 studies were RCTs. [7,16–21] Nine studies [7,9,13,15,16,18–21] reported postoperative pain according to VAS scale. Nine studies [9,13,15–21] mentioned total morphine at 24,48 h. Nine studies [9,11,13–16,18,20,21] evaluated length of hospital stay.…”