“…Table 1 shows the characteristics of the studies included and their classification in the hierarchy of evidence. The literature included was ranked with the fourth ( 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ), fifth ( 2 , 23 ), sixth ( 1 , 6 , 24 – 25 ) and seventh ( 3 , 4 , 5 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ) hierarchy of evidence levels.…”