Sclerotherapy, which takes its name from a Greek word meaning "hardening," is a method of treating enlarged veins by injecting an irritating chemical called a sclerosing agent into the vein. The chemical causes the vein to become inflamed, which leads to the formation of fibrous tissue and closing of the lumen, or central channel of the vein.
Sclerotherapy in the legs is performed for several reasons. It is most often done to improve the appearance of the legs, and is accomplished by closing down spider veins—small veins in the legs that have dilated under increased venous blood pressure. A spider vein is one type of telangiectasia, which is the medical term for a reddish-colored lesion produced by the permanent enlargement of the capillaries and other small blood vessels. The word telangiectasia comes from three Greek words that mean "end," "blood vessel," and "stretch out." In a spider vein, also called a "sunburst varicosity" there is a central reddish area that is visible to the eye because it lies close to the surface of the skin; smaller veins spread outward from it in the shape of a spider's legs. Spider veins may also appear in two other common patterns—they may look like tiny tree branches or like extra-fine separate lines.
In addition to the cosmetic purposes sclerotherapy serves, it is also performed to treat the soreness, aching, muscle fatigue, and leg cramps that often accompany small- or middle-sized varicose veins in the legs. It is not, however, used by itself to treat large varicose veins.
Sclerotherapy as a general treatment modality is also performed to treat hemorrhoids (swollen veins) in the esophagus.
Causes of spider veins
To understand how sclerotherapy works, it is helpful to begin with a brief description of the venous system in the human body. The venous part of the circulatory system returns blood to the heart to be pumped to the lungs for oxygenation. This is in contrast to the arterial system, which carries oxygenated blood away from the heart to be distributed throughout the body. The smallest parts of the venous system are the capillaries, which feed into larger superficial veins. All superficial veins lie between the skin and a layer of fibrous connective tissue called fascia, which covers and supports the muscles and the internal organs. The deeper veins of the body lie within the muscle fascia. This distinction helps to explain why superficial veins can be treated by sclerotherapy without damage to the larger veins.
Veins contain one-way valves that push blood inward and upward toward the heart when they are functioning normally. The blood pressure in the superficial veins is usually low, but if it rises and remains at a higher level over a period of time, the valves in the veins begin to fail and the veins dilate, or expand. Veins that are not functioning properly are said to be "incompetent." As the veins expand, they become more noticeable because they lie closer to the surface of the skin, forming the typical patterns seen in spider veins.
Some people are at greater risk for developing spider veins. These risk factors include:
- Sex. Females in any age group are more likely than males to develop spider veins.
- Genetic factors. Some people have veins with abnormally weak walls or valves. They may develop spider veins even without a rise in blood pressure in the superficial veins.
- Pregnancy. A woman's total blood volume increases during pregnancy, which increases the blood pressure in the venous system. In addition, the hormonal changes of pregnancy cause the walls and valves in the veins to soften.
- Using birth control pills.
- Obesity. Excess body weight increases pressure on the veins.
- Occupational factors. People whose jobs require standing or sitting for long periods of time without the opportunity to walk or move around are more likely to develop spider veins than people whose jobs allow more movement.
- Trauma. Falls, deep bruises, cuts, or surgical incisions may lead to the formation of spider veins in or near the affected area.
In typical outpatient sclerotherapy treatment, the patient changes into a pair of shorts at the doctor's office and lies on an examination table. After cleansing the skin surface with an antiseptic, the doctor injects a sclerosing agent into the veins. This agent is eliminated when the skin is stretched tightly over the area with the other hand. The doctor first injects the larger veins in each area of the leg, then the smaller ones. In most cases, one injection is needed for every inch of spider vein; a typical treatment session will require five to 40 separate injections. No anesthetic is needed for sclerotherapy, although the patient may feel a mild stinging or burning sensation at the injection site.
The liquid sclerosing agents that are used most often to treat spider veins are polidocanol (aethoxysklerol), sodium tetradecyl sulfate, and saline solution at 11.7% concentration. Some practitioners prefer to use saline because it does not cause allergic reactions. The usual practice is to use the lowest concentration of the chemical that is still effective in closing the veins.
A newer type of sclerosing agent is a foam instead of a liquid chemical that is injected into the veins. The foam has several advantages: It makes better contact with the wall of the vein than a liquid sclerosing agent; it allows the use of smaller amounts of chemical; and its movement in the vein can be monitored on an ultrasound screen. Sclerosing foam has been shown to have a high success rate with a lower cost, and causes fewer major complications.
After all the veins in a specific area of the leg have been injected, the doctor covers the area with a cotton ball or pad and compression tape. The patient may be asked to wait in the office for 20–30 minutes after the first treatment session to ensure that there is no hypersensitivity to the sclerosing chemicals. Most sclerotherapy treatment sessions are short, lasting from 15 to 45 minutes.
It is not unusual for patients to need a second treatment to completely eliminate the spider veins; however, it is necessary to wait four to six weeks between procedures.
The most important aspect of diagnosis prior to undergoing sclerotherapy is distinguishing between telangiectasias and large varicose veins, and telangiectasias and spider nevi. Because sclerotherapy is intended to treat only small superficial veins, the doctor must confirm that the patient does not have a more serious venous disorder.
Spider nevi, which are also called "spider angiomas," are small, benign reddish lesions that consist of a central arteriole, which is a very small branch of an artery with smaller vessels radiating from it. Although the names are similar, spider nevi occur in the part of the circulatory system that carries blood (away) from the heart, whereas spider veins occur in the venous system that returns blood to the heart. To distinguish between the two, the doctor will press gently on the spot in the center of the network. A spider nevus will blanch, or lose its reddish color, when the central arteriole is compressed. When the doctor releases the pressure, the color will return. Spider veins are not affected by compression in this way. In addition, spider nevi occur most frequently in children and pregnant women, rather than in older adults. They are treated by laser therapy or electrodesiccation, rather than by sclerotherapy.
After taking the patient's medical history, the doctor examines the patient from the waist down, both to note the location of spider veins and to palpate (touch with gentle pressure) them for signs of other venous disorders. Ideally, the examiner will have a small raised platform for the patient to stand on during the examination. The doctor will ask the patient to turn slowly while standing, and will be looking for scars or other signs of trauma, bulges in the skin, areas of discolored skin, or other indications of chronic venous insufficiency. While palpating the legs, the doctor will note areas of unusual warmth or soreness, cysts, and edema (swelling of the soft tissues due to fluid retention). Next, the doctor will percuss certain parts of the legs where the larger veins lie closer to the surface. By gently tapping or thumping on the skin over these areas, the doctor can feel fluid waves in the veins and determine whether further testing for venous insufficiency is required. If the patient has problems related to large varicose veins, these must be treated before sclerotherapy can be performed to eliminate spider veins.
Some conditions and disorders are considered contraindications for sclerotherapy:
- Pregnancy and lactation. Pregnant women are advised to postpone sclerotherapy until at least three months after the baby is born, because some spider veins will fade by themselves after delivery. Nursing mothers should postpone sclerotherapy until the baby is weaned because it is not yet known whether the chemicals used in sclerotherapy may affect the mother's milk.
- A history of AIDS, hepatitis, syphilis, or other diseases that are carried in the blood.
- Heart conditions.
- High blood pressure, blood clotting disorders, and other disorders of the circulatory system.
Patients are asked to discontinue aspirin or aspirin-related products for a week before sclerotherapy. Further, they are told not to apply any moisturizers, creams, tanning lotions, or sunblock to the legs on the day of the procedure. Patients should bring a pair of shorts to wear during the procedure, as well as compression stockings and a pair of slacks or a long skirt to cover the legs afterwards.
Most practitioners will take photographs of the patient's legs before sclerotherapy to evaluate the effectiveness of treatment. In addition, some insurance companies request pretreatment photographs for documentation purposes.
Aftercare following sclerotherapy includes wearing medical compression stockings that apply either 20–30 mmHg or 30–40 mmHg of pressure for at least seven to 10 days (preferably four to six weeks) after the procedure. Wearing compression stockings minimizes the risk of edema, discoloration, and pain. Fashion support stockings are a less acceptable alternative because they do not apply enough pressure to the legs.
The surgical tape and cotton balls used during the procedure should be left in place for 48 hours after the patient returns home.
Patients are encouraged to walk, ride a bicycle, or participate in other low-impact forms of exercise (examples: yoga and tai chi) to prevent the formation of blood clots in the deep veins of the legs. They should, however, avoid prolonged periods of standing or sitting, and such high-impact activities as jogging.
Cosmetically, the chief risk of sclerotherapy is that new spider veins may develop after the procedure. New spider veins are dilated blood vessels that can form when some of the venous blood forms new pathways back to the larger veins; they are not the original blood vessels that were sclerosed. Some patients may develop telangiectatic matting, which is a network of new spider veins that surface around the treated area. Telangiectatic matting usually clears up by itself within three to 12 months after sclerotherapy, but it can also be treated with further sclerosing injections.
Other risks of sclerotherapy include:
- Venous thrombosis. A potentially serious complication, thrombosis refers to the formation of blood clots in the veins.
- Severe inflammation.
- Pain after the procedure lasting several hours or days. This discomfort can be eased by wearing medical compression stockings and by walking briskly.
- Allergic reactions to the sclerosing solution or foam.
- Permanent scarring.
- Loss of feeling resulting from damage to the nerves in the treated area.
- Edema (swelling) of the foot or ankle. This problem is most likely to occur when the foot or ankle is treated for spider veins. The edema usually resolves within a few days or weeks.
- Brownish spots or discoloration in the skin around the treated area. These changes in skin color are caused by deposits of hemosiderin, which is a form of iron that is stored within tissue cells. The spots usually fade after several months.
- Ulceration of the skin. This complication may result from reactive spasms of the blood vessels, the use of overly strong sclerosing solutions, or poor technique in administering sclerotherapy. It can be treated by diluting the sclerosing chemical with normal saline solution.
- Hirsutism. Hirsutism is the abnormal growth of hair on the area treated by sclerotherapy. It usually develops several months after treatment and goes away on its own. It is also known as hypertrichosis.