Arterial Wall and Tissue Penetration Force With Various Cannulas and Needles

Abstract

Background Vascular penetration during aesthetic filler injections can cause serious side effects such as skin necrosis and blindness. Objectives To analyze the effect of cannula brand and gauge on the risk of vascular penetration. Methods The minimal force to penetrate the superficial temporal artery with 3 cannula brands and 1 needle brand in 4 sizes (22, 25, 27, and 30-gauge) was measured in 4 fresh frozen cadavers utilizing a force gauge that measures as low as 0.1 newtons. Tissue penetration force in the subdermal plane of the nasolabial fold was measured and compared to retrospective training data in live humans. A second site repeated the arterial penetration test on one fresh cadaver with 2 different force gauges. Results Significantly lower forces were needed with all size needles vs the same gauge cannulas in all brands to penetrate the cadaveric artery and advance in the subdermal plane of the nasolabial fold in both cadavers and live humans. To successfully enter the artery in a cadaver with any cannula, numerous attempts were necessary. The tissue penetration force in the subdermal plane of the nasolabial fold in a cadaver was not significantly different than a living person; however, it was significantly higher than the arterial penetration force in a dissected cadaver. Conclusions All gauge cannulas (including 27 and 30-gauge), require more force than the same size needle to penetrate an artery. However, it appears the friction coefficient and flexibility, not the arterial penetration force, is the most important factor in keeping the instrument outside the vessel.