Study Group VAS
before
therapy 		Frequency of
TN attacks
per day 		VAS
at endpoint 		Follow-up Frequency of
TN attacks
at endpoint
Wu et al. [27] BT-A 7.05 (2.03) 21.71 (22.68) 1.8 2016 h 0 m 0 s 2
Placebo (2.25) 20.53 (10.38) 5 19
Shehata et al. [28] BT-A 8.3 36.7 (3.13) 1.8 2016 h 0 m 0 s 4 (7.12)
Placebo 8.5 39.2 (3.05) 8.2 36.1 (13.45)
Zúñiga et al. [29] BT-A 8.85 29.1 4.59 2664 h 0 m 0 s 7.1
Placebo 8.19 31.06 6.94 21.25
Zhang et al. [30] BT-A (25 U) 6.24 (2.13) - 2 1344 h 0 m 0 s -
BT-A (75 U) 7.18 (2.21) - 1.8 -
Placebo 6.96 (1.97) - 3.8 -

U = units per ml of solution; BT-A = botulinum toxin type A; TN = trigeminal neuralgia.