Fig. 4

A forest plot diagram showing VAS at rest. The pooled results showed that SSNB group had higher VAS at rest in PACU (MD = 0.56, 95% CI [0.19, 0.94], P = 0.003) and 1 h after operation (MD = 0.92, 95% CI [0.28, 1.57], P = 0.005), however, lower VAS at 12 h after operation (MD = −0.71, 95% CI [−1.12, −0.3], P = 0.0006). No significant difference was found for VAS at rest 2 h after operation (MD = 0.12, 95% CI [−0.16,0.4], P = 0.39), 3-4 h (MD = 0.21, 95% CI [−0.21, 0.64], P = 0.32), 6-8 h (MD = −0.28, 95% CI [−0.56, 0.00], P = 0.05), 1 day (MD = −0.13, 95% CI [−0.64, 0.38], P = 0.62), and 2 days after operation (MD = −0.12, 95% CI [−0.71, 0.48], P = 0.7)