varicose veins treatment foam

foam sclerotherapy

Sclerotherapy is one of the most versatile techniques for the treatment of varicose veins and is the most common treatment used as an addition to surgery. In some indications, it is replacing phlebectomy and vein stripping.

Technical aspects

The practice of sclerotherapy entails substantial variability in terms of the materials used, the preparation method and its application. Although there are international guidelines and consensus documents that try to summarise all the related aspects, including indications, strategies, materials and risk prevention, sclerotherapy remains an operator-dependent “art” that requires specific training. The quality of the foam is important, and even more critical is ensuring the right indications, strategy and application technique.

  • Practically all types of varicose veins; larger veins have greater risk of recurrence.
  • Recurrent varicose veins.
  • Elderly patients.
  • Low-flow venous malformations.
  • In small spider veins there is no consensus on the use of foam; as foam can be highly irritant, the clinical guidelines generally describe the use of liquid sclerotherapy to minimise such unwanted effects.
  • It is recommended to inject no more than 10 mL of air-based foam; above this volume, the risk of adverse events increases.
  • The use of physiological gases increases the safety margins, but does not completely eliminate the risk of adverse events.
  • 5 mL to 10 mL syringes are recommended. Smaller syringes improve foam stability but exert greater injection pressure.
  • The ideal syringes are 5 mL or 10 mL 2-piece syringes. Silicone (3‑piece) syringes are not recommended.
  • Glass syringes provide maximum stability but their handling and need for resterilisation are inconvenient.
  • Some specific brands have a very detrimental effect on foam stability, especially if an ionic sclerosant is used.
  • Air-based foams are more stable, but their nitrogen content limits injection volumes due to its low solubility in the blood.
  • The use of O2/CO2 mixes at various proportions gives increased safety margins in terms of injection volume, but at the expense of stability.
  • Polidocanol/ethoxysclerol (POL) is the most commonly-used sclerosant.
  • Tetradecyl sodium sulfate (STS) has greater irritant potential that POL and generates foam more quickly but is less stable.
  • Agitated chromated glycerin does not produce foam.
  • Foam stability is determined by 3 factors: coalescence, gravitational drainage, and gas diffusion.
  • The higher the quantity of gas in the foam, or gas-to-liquid ratio, the greater the stability.
  • The higher the concentration of sclerosant, the greater the stability.
  • Ionic sclerosants (STS) are less stable.
  • O2/CO2 combinations are less stable than air. CO2 confers the most instability, although it is the most soluble in blood.
  • Low temperatures favour foam stability.
  • It is recommended to limit injection volume to 10 mL if using air-based foam.
  • Veins should be emptied of blood before foam injection to potentiate its effect and reduce inactivation of the sclerosant.
  • The treated limb should be rested and elevated for at least 10 minutes during/after treatment.
  • Avoid Valsalva manoeuvres immediately after treatment.
  • Encourage early mobilisation and exercises to contract and relax the calf muscles.
  • Known allergy to the sclerosant to be used.
  • Acute thrombotic process or disease.
  • Immobility.
  • There are other relative contraindications that should be evaluated on an individual basis. See references.

If you want to know more about sclerotherapy or consult the referenced bibliography, visit the following link

View References

This space is aimed exclusively at health professionals.


By using this page, you acknowledge that you belong to this group.