“…The studies were conducted in the United State 15,16,22,28,29 , Japan 30 , Belgium 31 , Brazil 32 , Spain 33 , Germany 34 , and Sweden 35 . There were 6 retrospective studies 14,15,20,29,30,32 , 2 prospective cohort studies 28, 34 , 2 case series 16,22 , and 1 randomized control trial 35 . The postoperative evaluation of PSG ranged from 1 day to 108 months.…”