Table 2.

Risk of bias assessment conducted using the Cochrane risk of bias tool of the included studies

Author	Allocation Bias	Performance Bias	Attrition Bias	Detection Bias	Reporting Bias
Charytan et al. (13)	Low	Some concern	Low	Some concern	Low
Ziaee et al. (11)	Some concern	Some concern	Low	Low	Low
Hammer et al. (12)	Some concern	Low	Low	Some concern	Low
Lin et al. (14)	Low	Some concern	Some concern	Low	Low
Feniman-De-Stefano et al. (25)	Some concern	Low	Low	Some concern	Low
Yongsiri et al. (28)	Some concern	Some concern	Low	Low	Low
Walsh et al. (15)	Low	Low	Low	Low	Low
Ito et al. (17)	Low	Low	Low	Low	Low
Matsumoto et al. (16)	Some concern	Some concern	Low	Low	Low
Ni et al. (26)	Some concern	Low	Low	Some concern	Some concern
Taheri et al. (18)	Some concern	High	Low	Low	Some concern
Vukusich et al. (19)	Some concern	Low	Some concern	Low	Low
Taheri et al. (20)	Some concern	Some concern	Some concern	Low	Some concern
Gross et al. (27)	Some concern	Low	Low	High	Some concern