Comment to: An investigation of the influence of glycerin on sclerosant foam stability, by Peterson JD, Goldman MP. Phlebology 2011;26:232-4.

In a recent article, Cavezzi and Tessari speculated that the addition of glycerin may prolong half liquid time. The Authors studied the stability of sodiumtetradecyl sulphate (STS) after addition to glycerin 72%. The sclerosant combinations investigated were: 1.0 mL 0.5% STS to 0 mL 72% glycerin; 0.9 mL 0.5% STS to 0.1 mL 72% glycerin; and 0.8 mL 0.5% STS to 0.2 mL 72% glycerin. For each trial, 1.0 mL of 0.50% STS sclerosant was charged using new sterile syringes and connectors attached to a W/W adaptor and to a 5 mL syringe with 4 mL of pre-drawn air. Using the double-syringe system technique, air is pushed to fill the syringe with the sclerosing agent. This method usually requires ten passages from one syringe to the other. Finally, the 5 mL syringe filled with the foam iss placed exactly vertically with the rubber stopcock on the bottom and the timer is started. As the foam degenerates back into its constituents, the sclerosing solution gradually re-forms at the bottom of the syringe. When the solution’s meniscus reaches a volume of 0.5 mL (half of the original sclerosing volume of 1.0 mL), the timer is stopped and data are recorded. Table 1 clearly shows that the addition of glycerin to foam prolongs foam stability due to the increased viscosity of glycerin, increasing the STS foam half-life by 35.29%. Possibly more efficacious sclerotherapy could be achieved from a prolonged contact time of the foam bubbles with the endothelial cells. However, this same prolonged stability could cause an increase in the incidence of distant side effects. The most effective amount of glycerin into the solution still needs to be studied.