Table 4.

Injection protocol and administration

Study	Group	Injection
		Injection protocol	Administration of injections
Wu et al. [27]	BT-A	75 U (1.5 mL) of BT-A were applied at 15 points, 5 U (0.1 mL) per point in trigger points	Intradermally and/or submucosally
	Placebo
Shehata et al. [28]	BT-A	Every patient received either BT-A (100 U BOTOX® in 2 mL preservative-free normal saline, resulting in a concentration of 5 units/0.1 mL) or placebo (2 mL 0.9% NaCl). Overall injected doses ranged from 40 units (8 injection points) to 60 units (12 points)	Subcutaneously
	Placebo
Zúñiga et al. [29]	BT-A	A 1 mL syringe: 0.9% saline plus 50 U of BT or only 1 mL of 0.9% saline were administered in various sites, 1 cm apart from one another in the path of the branch/branches involved.	Subcutaneously
	Placebo
Zhang et al. [30]	BT-A (25 U)	BT-A or the same volume of isotonic saline were applied at 20 points, (0.05 ml) per point, between the epidermis and dermis of the skin where pain was experienced according to the patient's description.	Intradermally and/or submucosally
	BT-A (75 U)
	Placebo

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