The History of Sclerosing Foams

Dermatol Surg 30:5:May 2004 WOLLMANN: THE HISTORY OF SCLEROSING FOAMS 699
1969—Walter Gillesberger: 22 Low-Pressure
Technique
Gillesberger’s technique was based on the generation
of a negative pressure in a (glass) syringe, so that air
could enter through the capillary gap between the
syringe piston and the plunger and thus generate
bubbles (see Figure 7). Gillesberger’s syringe was not
closed hermetically like the Monfreux syringe tip later
on, but the negative pressure was strong enough to
create a foam and was not compensated by the inflow
of the sclerosant from the vial. The technique by
Gillesberger or its refinement by Monfreux, who
generated foam with an ‘‘absolute’’ negative pressure,
is very simple. What is problematic is that there is no
standardized ratio between air and sclerosant. Therefore,
the foams produced in that manner are different,
depending on the syringe type, needle, generated
suction, and the resulting gas content; they may be
more fluid one time and more viscous another time.
This leads to different behavior in the vessel (degree
and duration of the displacement of blood) and thus
probably to an unpredictable efficacy in vivo. (The
ability of foam to displace blood depends on its quality
or characteristics: foams obtained with low sclerosant
concentrations, with small amounts of air, and/or with
rather large bubbles have a more or less fluid behavior;
i.e., they are more easily washed away by liquids
(blood) and have no or just a small and short-term
displacing effect. Viscous foams (higher concentration,
higher gas content, and small bubbles), in contrast,
basically have a displacing effect in larger vessels. 41 If
sclerosing foam is to be used for small diameter veins,
precaution is recommended owing to the enhancement
of the efficacy. A viscous foam would probably have
too a strong effect in small veins; moreover, the foam
breaks down as a result of the passage through the
required fine needles. 42
Figure 7. The low-pressure technique: Pulling down the piston
allowed air to enter the syringe through the tiny gap between the
syringe piston and the plunger.
1984—Gerald Hauer: 23 Twin-Syringe Technique
Hauer patented a twin-syringe set for foam preparation:
Two parallel syringes, one filled with air, the
other one filled with sclerosing solution, are simultaneously
emptied into a ‘‘mixing chamber’’ by pressure,
which leads to the formation of bubbles. The ratio of 1
plus 1 (sclerosing agent and air) suggests a dispersion
that should have the effect of a foam block.
1986—Michael Grigg: 24 Double Syringes and
Connecting Tubes
In 1986, Grigg demonstrated a new foam production
procedure: the principle was the generation of a
turbulent flow between two syringes, connected via a
plastic infusion tube, so that fluid and air could be
pumped forward and backward. Belcaro later improved
this technique by the addition of a further
strongly foaming detergent solution in small amounts
(0.1–0.2 mL). (‘‘Improved’’ in this context means
prolongation of half-life. Owing to the commonly
relevant amount of silicone in disposables (syringes
and infusion tubes, etc.), the half-life of the foam was
evidently limited because silicone, which destroys the
surfactant arrangement of the foam lamellae, is a very
strong foam breaker. Therefore, anything that contributes
to the maintenance of foam bubbles supports
the foam stability: this is, in addition to an increase of
the surfactant concentration, in particular the minimization
of the amount of silicone.) According to him,
the foam half-life was approximately 4 min. This socalled
‘‘Irvine technique’’ (named after the laboratory
in which the technique was demonstrated) can be
considered to be a precursor of Tessari’s technique and
the double-syringe system (DSS). Belcaro and coworkers
24 first performed investigations on the safety of
the foam generated according to that technique: 5 to
10 mL of the foam produced with that technique did
not cause any change of the pulmonary ventilation
scintigraphy or perfusion scintigraphy in 12 patients.
1995—Juan Cabrera Garrido: 2 Rotating Brush
Technique
In 1995, Cabrera Garrido published data from the
clinical use of ‘‘microfoam.’’ He had treated venous
malformations and saphenous veins including collaterals
with high volumes of foam. His objective was to
fill the complete venous lumen by injecting high doses
of foam at one time. A new aspect of the production
was the use of a high-speed rotating brush (a modified
dental bur), so that foam was agitated—like cream
with a food mixer—and the facultative addition of
CO2 as a carrier gas. In experiments, CO2—if