The History of Sclerosing Foams

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Dermatol Surg 30:5:May 2004 WOLLMANN: THE HISTORY OF SCLEROSING FOAMS 697 strength of foams needs to be respected if thinking about sclerosing smaller vessels with foam. 1953—Arve Ree: 14 First Use of ‘‘Pure Foam’’ The Norwegian doctor Ree introduced a new era in 1953: He was the first to inject ‘‘pure’’ foam, not in addition to air and common fluid sclerosant but instead of the sclerosant and, in particular, without the previous injection of air. With his technique (agitation of a detergent solution in the vial and subsequent aspiration of the bubbles into the syringe) he first treated a series of 50 patients very successfully. He injected 2 to 7 mL of foam, depending on the vessel diameter, corresponding to an amount of air of up to 6.6 mL. The bubble sizes seem to have been in the millimeter range with that technique. Owing to the higher kinetic energy (agitation of a vial and subsequent passage through a bottleneck with turbulent flow), it may be considered that a foam with smaller bubbles than with the previous techniques could be generated. 1956—Peter Flückiger: 15 Retrograde Injection, Aspiration Technique, and Leg Elevation Flückiger recommended the technique known as ‘‘retrograde sclerotherapy,’’ a technique characterized by leg elevation and sclerosant injection into saphenous veins from a proximal injection site in the distal direction. Thus, the sclerosant could reach all insufficient collaterals and the saphenous vein by one injection. He obtained better results by using sclerosing foam than with fluid sclerosants: ‘‘Basically, the procedure consists in injecting y Varsyl foam (ethanolamine oleate) into an appropriate vein. Due to the buoyancy, the foam has only a low tendency to move in central direction with the blood flowy. After removal of the needle, the location of the ‘‘foam seal’’ can be determined by palpationy. The foam usually spreads in the surrounding of the injection site in distal and proximal direction. After injection, the intravascular foam depot y is displaced by manual massage against the periphery.’’ Flückiger additionally mentioned major aspects of modern foam sclerotherapy in his publication: He saw that the foam he used remained in the region of the injection site as a ‘‘depot,’’ noticed that it was able to displace the blood in the proximal direction and was not washed away from the blood, and noticed that the foam could be directed to other regions by manual manipulation. Moreover, he postulated and discussed further treatment-relevant foam properties for the first time: Increased efficacy by increase of the effective surface of foam compared to fluid sclerosants; A stronger sclerosing effect with smaller amounts of sclerosants; Postulation of a minimized bubble size; and Postulation of homogeneity of foam. It is obvious that a given amount of sclerosant in the form of foam has a much larger surface than it has in an unchanged, fluid state: the smaller the bubbles of the foam are, the greater the surface. Since damage to the intima y is based on the contact of the intima with the sclerosant, the use of foam allows an extended sclerosation with a small amount of sclerosant. The preparation of a homogenous, fine-bubbled foam is an important condition for the success of the procedure. (The homogeneity of foam, i.e., a foam whose bubbles are as homogenous as possible, is an important prerequisite for its flow behavior (viscosity) and its stability. Ideally, a foam has only bubbles of the same diameter, which is, in reality, barely or never feasible. Foam is subjected to aging, which involves mainly two aspects: In contrast, the fluid that is between the gas bubbles in a young foam drains owing to the force of gravity, so that the upper bubbles slowly break down because of the ‘‘fluid deficiency.’’ In contrast, bubbles disappear because a gas diffusion takes place between the foam bubbles. The internal gas pressure is higher in small bubbles owing to the higher surface tension, so that gas moves from those bubbles into larger bubbles. Smaller bubbles of a foam get even smaller and large ones even larger—until they break down. In a homogenous foam, all bubbles would have the same inner gas pressure. A gas diffusion from one bubble to the adjacent bubble would not take place and the foam would remain stable until just the drain process would contribute to aging.) Flückiger considered the various known foam manufacturing procedures, and suggested his own new technique: ‘‘In order to obtain a homogenous finebubbled foam, the procedure consisting in the agitation of a syringe filled with air and sclerosant [Orbach’s technique 1950] is completely inappropriate. The drawing of air through a sclerosant in the syringe [Sigg’s technique 1949] does not yield a small fine-bubbled foam either. Moreover, none of these methods is able to convert the entire amount of sclerosant into foam. There is always a certain amount of remaining fluid, which cannot be used for retrograde sclerotherapy with the elevated leg. A perfect, fine-bubbled foam is obtained by the simultaneous aspiration of sclerosant y and air through a thin injection needley. The thin injection needle (the narrower the lumen, the finer the foam) y is
698 WOLLMANN: THE HISTORY OF SCLEROSING FOAMS Dermatol Surg 30:5:May 2004 Figure 5. The aspiration technique: The tip of the needle was placed at the liquid–air interface, thus allowing coaspiration of air and sclerosant that would generate foam in one run. introduced into the ampoule in such a way that approximately two thirds of the opening of the bevel are imbibed in the fluid (see Figure 5). When drawing back the plunger, the syringe fills with Varsyl foam under a sizzling noise, the foam remaining stable for several minutes.’’ 1957: Heinz Mayer and Hans Brücke: 16 First Microfoam Device (Double-Piston Syringe) A milestone regarding the improvement and standardization of sclerosing foam was the publication by two surgeons Mayer and Brücke: they described the first device that had been developed specifically for the preparation of viscous sclerosing foams, a syringe with a double plunger (see Figure 6). (A double-plunger syringe following the principle of Mayer-Brücke was ‘‘reinvented’’ several times in the following decades. A very homogenous, extremely fine microbubble foam can be produced using a simple reproduction of that syringe—unfortunately, the original is no longer available. More than 40 years ago, Mayer and Brücke worked with foams that are now suggested to be classified as ‘‘microfoam.’’ 17 ) ‘‘Before the main plunger, there is a second, thin plunger with numerous holes, whose piston leads to a central bore of the main plunger and protrudes it. When the main plunger is fixed, the plunger provided with holes can rapidly be moved forward and backward and the Phlebocid (ethanolamin oleate) can be mixed with the air contained in the syringe. A finebubbled, viscous foam developsy. We have tested Figure 6. The Mayer-Brücke device: The inner plunger with numerous tiny holes can rapidly be moved forward and backward to mix sclerosant and air contained in the syringe. The outer plunger was used for injection of the viscous and fine-bubbled foam. most sclerosants of similar composition and selected Phlebocid, which provides the stiffest foam upon agitation with a homogenous distribution of air bubblesy. We consider the greatest advantage of the use of foam y to be the homogenous distribution of the sclerosanty.’’ Clinically, they stated after administration of foam: ‘‘The fibrous tissue of the venous lumen is so complete that in general, recanalizationydoes not occur. We never observed recurrent varicose veins after using Phlebocid foam. We never observed complications after foam filling such as air embolisms or skin necroses.’’ 1962—Peter Flückiger: 18 Turbulent Flow In 1962, Flückiger described another technique for the preparation of foam: pumping of air and sclerosant forward and backward between a drug vial and the attached syringe. Later, this technique was modernized and improved by Alessandro Frullini 19,20 by adding an adapter between the syringe and the bottle seal. Furthermore, Flückiger changed some points since his first publication in 1956: he maintained leg elevation not only during sclerotherapy but also for some minutes thereafter, to allow the foam to degrade. He warned therapists to be cautious while ‘‘stroking’’ the foam seal in a peripheral direction to prevent any unintended movement of foam into the deep venous system. Today, it is recommended that you wait some minutes after foam sclerotherapy of large veins before applying compression. 42 1963—Peter Lunkenheimer: 21 First Use of Polidocanol Foam Even before polidocanol received its first marketing authorization, a German physician had the chance to use the novel sclerosing solution for research purposes for the first time. Kreussler’s archives revealed a letter from that phlebologist, which contains a written ‘‘case report’’ about the first patient treatment: ‘‘The first patient was treated with 2 mL Aethoxysklerol s foamy.’’
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The History of Sclerosing Foams

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