Sclerotherapy is a minimally invasive medical procedure designed to treat undesirable veins, primarily on the legs. It involves injecting a specialized chemical solution, known as a sclerosant, directly into the affected blood vessel. This triggers a reaction that causes the vein to close and eventually disappear. The sclerosant addresses both cosmetic concerns and the painful symptoms associated with venous disease. Selecting the appropriate sclerosant is central to treatment success, as different agents are used depending on the size and location of the targeted vein.
Sclerotherapy: The Basics
The purpose of sclerotherapy is to eliminate small varicose veins and spider veins by intentionally collapsing them. This therapeutic approach forces blood to reroute through healthier vessels located deeper within the leg. Treating these superficial, dysfunctional veins can alleviate symptoms such as aching, burning, and cramping associated with poor circulation. The ultimate goal is to generate a controlled inflammatory response inside the vein wall, leading to the vessel’s permanent closure and absorption by the body.
The procedure involves injecting the sclerosant solution directly into the target vein using a fine needle. This irritates the interior lining, causing the vein to swell and adhere to itself. Following treatment, compression is typically applied to ensure the vein walls remain sealed shut.
Primary Sclerosant Agents and Their Classification
Sclerosant agents are broadly categorized into three main chemical types: detergents, osmotic agents, and chemical irritants. Detergents are the most commonly used type and function by damaging the cell membranes of the vein wall through protein denaturation. Examples include Polidocanol and Sodium Tetradecyl Sulfate (STS). STS is generally about twice as potent as Polidocanol, requiring a lower concentration for the desired effect. Detergent sclerosants can be administered as a liquid or mixed with a gas, such as air or carbon dioxide, to create a foam.
Foam sclerotherapy is useful for treating larger or longer veins because the foam displaces the blood, allowing for greater contact with the vein wall. Osmotic agents, such as Hypertonic Saline Solution, work by shifting the water balance in the vein cells, causing them to dehydrate and collapse. Hypertonic saline is a naturally occurring bodily material but can cause pain and tissue damage if it leaks outside the vein. The third class, chemical irritants, includes agents like Glycerin, which directly cause caustic destruction of the endothelial lining. The choice among these agents is determined by the size of the vessel, with lower concentrations used for smaller spider veins.
Mechanism of Vein Closure
The sclerosant’s action begins immediately upon contact with the inner layer of the vein, known as the endothelium. The solution triggers damage to the endothelial cells, stripping away the protective lining. This cellular injury induces an acute inflammatory reaction, often referred to as chemical phlebitis. This inflammation causes the vein walls to swell and stick together, effectively blocking blood flow. The collapsed vein then undergoes fibrosis, a process of scarring that permanently seals the vessel shut, allowing the body to gradually absorb the non-functional tissue.
Managing Adverse Reactions to Sclerosants
While sclerotherapy is generally a safe procedure, the chemical nature of the solutions can lead to specific adverse reactions. One of the most common issues is hyperpigmentation, appearing as brown, bruise-like staining on the skin near the injection site. This staining occurs when the sclerosant damages the vein, causing red blood cells to leak out and break down, depositing iron (hemosiderin) in the surrounding tissue. This discoloration is usually temporary but can sometimes take many months or even years to fully fade.
Another significant reaction is tissue necrosis, which is the localized death of skin tissue, occurring if the sclerosant solution leaks out of the vein and into the surrounding subcutaneous tissue. Detergent and osmotic agents, especially in higher concentrations, are known to cause this complication, requiring careful injection technique. Allergic reactions to the chemical agent are also possible, particularly with agents like Sodium Tetradecyl Sulfate (STS), although true anaphylaxis is very rare.