TABLE 1.

Characteristics of the included trials.

References	Country	Type of groups	Number of participants	Randomization and blinding	PNB technique	Observation time of pain	Quality assessment
Di Giuseppe et al. (21)	Switzerland	SP + PNB	23	1:1 ratio; double-blind	Ultrasound guided	6, 12, 24, and 48 h	Good
		SP	26
Rajabi et al. (20)	Iran	GA + PNB	30	1:1:1 ratio; double-blind	Anatomic landmarks	12 h	Good
		GA	30
		GA + placebo PNB	30
Imbelloni et al. (19)	>Brazil	SP + PNB	100	>1:1 ratio; double-blind	>Under nerve stimulation	>6, 12, 18, 24, and 30 h	>Good
		SP	100
Naja et al. (18)	Lebanese	GA + PNB	30	1:1:1 ratio; double-blind	Under nerve stimulation	6 h, 12 h, 24 h, 36 h, 48 h, 3 days, 4 days, 5 days, and 6 days	Good
		GA	30
		GA + placebo PNB	30
Brunat et al. (17)	France	GA + PNB	25	1:1 ratio; double-blind	Anatomic landmarks	1, 2, 4, 8, 12, and 24 h	Good
		GA	27
Luck and Hewett (16)	Australia	GA + PNB + LA	10	1:1 ratio; double-blind	Anatomic landmarks	0.5, 2, 4, and 24 h	Good
		GA + LA	10