If safety is defined as the diminished ability to penetrate facial arteries, the goal of this study was to investigate whether different-sized cannulas are safer than correspondingly sized needles for the application of facial soft-tissue fillers.
Two hundred ninety-four penetration procedures of the facial and superficial temporal arteries were performed in four fresh frozen cephalic specimens using both needles (20-, 22-, 25-, and 27-gauge) and cannulas (22-, 25-, and 27-gauge). Continuously increasing force was applied and measured until intraarterial penetration occurred.
No statistically significant differences were detected when comparing forces required to penetrate the facial arterial vasculature between different sexes, arteries, or sides of the face (all p > 0.05). Forces needed to penetrate significantly (p < 0.001) decreased with smaller diameter needles (20-gauge, 1.12 ± 0.29 N; 22-gauge, 1.08 ± 0.25 N; 25-gauge, 0.69 ± 0.24 N; and 27-gauge, 0.70 ± 0.29 N) and in cannulas (22-gauge, 1.50 ± 0.31 N; 25-gauge, 1.04 ± 0.36 N; and 27-gauge, 0.78 ± 0.35 N). Comparing 27-gauge injectors, no statistically significant difference was detected between needles and cannulas; an artery could be penetrated with a similar force independent of whether the injector was a needle or a cannula (0.70 ± 0.29 N versus 0.78 ± 0.35 N; p = 0.558).
Cannulas, in all measured sizes except 27-gauge, required greater forces for intraarterial penetration compared with correspondingly sized needles, confirming the safety of 22- and 25-gauge cannulas; 27-gauge cannulas, however, required similar forces as 27-gauge needles, indicating that 27-gauge cannulas are not safer than 27-gauge needles.
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