Arterial Wall and Tissue Penetration Force With Various Cannulas and Needles.

BACKGROUND: Vascular penetration during aesthetic filler injections can cause serious side effects such as skin necrosis and blindness. OBJECTIVES: The objective of this study was 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 measured as low as 0.1 Newtons. Tissue penetration force in the subdermal plane of the nasolabial fold was measured and compared with retrospective training data in live humans. The arterial penetration test was repeated at a second site on 1 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 in 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 that friction coefficient and flexibility, not the arterial penetration force, are the most important factors in keeping the instrument outside the vessel.

Zosteriform lymphangioma circumscriptum.

Lymphangioma circumscriptum (LC) is a form of lymphangioma involving skin and subcutaneous tissue. It is evident as translucent vesicles of varying size, though commonly 2 to 4 mm, and of a pink, red, or black hue. It is localized to the dermis, frequently extending deeply and laterally. LC may resemble other entities, such as metastatic carcinoma of the skin, lymphangiectasis, or herpes zoster. We report an unusual verruciform, zosteriform form of LC.