Sclerotherapy

CHAPTER 92 Sclerotherapy

Sclerotherapy is a technique used to eliminate unwanted veins (both varicosities and spider veins). This is accomplished by injecting a noxious agent into the lumen of the vein, which causes destruction of the endothelium with an inflammatory response. When used with compression, it results in obliteration of the vessel. The goal of treatment is to eradicate abnormal veins while preserving healthy veins.

Background

Ancient physicians, scholars, and poets, including Hippocrates and Homer, recognized varicose veins. Improvements in syringes and needles and the development of more effective and safe sclerosing solutions allowed sclerotherapy to become a modern and effective method of treatment. Clinicians now use sclerosants developed in the 20th century (e.g., hypertonic glucose, hypertonic saline, sodium morrhuate, chromated glycerin, ethanolamine oleate, and stabilized polyiodide iodine). However, the most popular agents used in sclerotherapy are sodium tetradecyl sulfate (Sotradecol), polidocanol (Aethoxysklerol), and hypertonic saline (Table 92-1).

TABLE 92-1 Most Common Sclerosing Agents in the United States

Organizations worldwide—including the American College of Phlebology and the American Venous Forum in the United States—have been formed to further research and education in venous disease. Recently, the American Medical Association has recognized phlebology as a separate and distinct medical specialty.

Anatomy

The venous system is divided into three levels: deep, perforating, and superficial veins. The veins treated with sclerotherapy are the perforating and the superficial veins.

Deep veins are encased in fascia and muscle. In ascending order, they are the anterior and posterior tibial veins, the peroneal vein, the tibioperoneal trunk, the popliteal vein, the superficial femoral vein, the deep femoral vein, the common femoral vein, and the iliac vein. These veins convey blood from the lower limb back to the heart (Fig. 92-1).

Figure 92-1 Main venous conduits formed by the deep veins of the lower limbs; numerous branch veins join these.

The superficial venous system is confined to the veins above the fascia in the subcutaneous tissue and involves the great and small saphenous veins and their tributaries, in addition to the lateral subdermal veins (of Albanese) around the knee (Figs. 92-2 and 92-3).

Figure 92-2 Normal anteromedial superficial venous anatomy is depicted. The great saphenous vein ascends from the dorsal venous arch and dominates the anteromedial superficial drainage system. It receives the posterior arch vein (vein of Michelangelo). It also receives variable anterior and posterior tributary veins in the anteromedial calf just below the knee. As the saphenous vein reaches its termination, it receives important tributaries medially and laterally. These tributaries are commonly visualized in duplex ultrasonographic examinations, which may identify reflux in one or both of these vessels.

Figure 92-3 The small saphenous vein dominates the posterolateral superficial venous drainage. It originates in the dorsal venous arch; at the posterolateral ankle, it is intimately associated with the sural nerve. Note the important posterolateral tributary vein and the posterior thigh vein, which ascends and connects the small saphenous venous system with the great saphenous venous system. The anterolateral superficial thigh vein and the posterolateral tributary vein can be very important in congenital venous anomalies, such as Klippel-Trénaunay syndrome.

Approximately 150 perforating veins connect the superficial and deep systems. Many of these veins are eponymous with the anatomists who demonstrated them (Fig. 92-4). In the middle area of the thigh are the Hunterian perforators, and in the distal thigh are the Dodd perforators. These veins connect the thigh portion of the great saphenous vein to the femoral vein. Below the knee is Boyd’s perforator, connecting the great saphenous vein to the popliteal vein. The infrapopliteal perforating veins along the medial aspect of the leg connect a major branch of the saphenous vein, the posterior tibial arch vein, to the posterior tibial vein.

Figure 92-4 Locations of the most important perforating veins associated with the great saphenous system are shown. Note that the Cocketts and inframalleolar perforating veins are actually separate from the great saphenous system. The Boyd perforating vein is constantly present, but it may drain the saphenous vein or its tributaries. Perforating veins in the distal third of the thigh are referred to as Dodd perforators, whereas those in the middle third of the thigh are referred to as Hunterian perforators.

There are also important perforating veins along the posterior aspect of the calf, which connect the small saphenous system to the tibial venous system, and perforators along the lateral aspect of the knee that connect the lateral subdermal plexus of Albanese to the deep venous system.

There are several important connections from the superficial venous system to the deep femoral vein. The posterior thigh perforator connects the superficial veins of the posterior thigh to the deep femoral vein. In addition, the inferior gluteal vein and the veins of the medial thigh connect through the internal pudendal system to the deep pelvic veins. It is the latter system that results in the vulvar varicosities seen frequently in pregnancy. Although it is not necessary to remember all of the proper names of these perforators, it is important for the clinician to have knowledge of their location so that sclerotherapy can be carried out in a logical and effective manner.

In general, unwanted veins are referred to as telangiectases, reticular varicosities, or varicose veins (Table 92-2).

TABLE 92-2 Vessel Classification

Physiology

Primary Varicose Veins

The veins of the lower limb carry blood against the force of gravity back to the heart. This is accomplished by two principal means. When the muscles of the calf contract, they compress the soleal sinuses and the deep veins encased in fascia and muscle, achieving a pressure of up to 300 cm H₂O. Because the veins of the lower limb have valves that allow blood to flow only in a proximal direction, the column of blood is forced into the valveless veins of the abdomen.

If a person is standing still, the pressure of the veins on the dorsum of the foot will equal the distance from the foot to the right heart. This results in an average pressure of approximately of 70 to 80 cm H₂O. As evidenced by the pressure relationship mentioned previously, the pressure exerted by the contraction of the calf muscles is sufficient to overcome the effects of gravity and propel blood in a proximal direction. The flow of venous blood from the calf back to the heart may be considered the systolic phase. During this phase, blood is prevented from going into the superficial venous system by the valves of the perforating veins. During the relaxation phase, when the pressure in the calf compartment is diminished, blood can flow from the superficial veins through the perforators into the deep veins. Therefore, the superficial venous system may be likened to an atrium of the heart, and the deep veins of the calf may be likened to a ventricle.

This physiologic system breaks down when the walls of the veins dilate, causing the valves to become incompetent. The manner in which veins become incompetent is somewhat controversial. The belief has been that the problem is initiated by a malfunctioning valve. The incompetent valve allows blood to flow in a reverse direction as gravity pulls it down toward the foot. The resulting increase in venous pressure causes the veins to dilate and sequentially creates incompetence in the more distal valves. Although this incompetence still may occur, especially in patients who have had phlebitis, which can destroy the valve structure, it now seems likely that in patients who develop primary varicose veins the initiating event is dilation of the vein itself.

The most proximal valve of the superficial system is at the saphenofemoral junction. This valve normally allows blood to flow from the great saphenous vein into the common femoral vein. When this valve becomes incompetent, blood will flow from the common femoral vein into the great saphenous vein, causing progressive dilation of the saphenous vein. This dilation can affect more distal valves, causing them to become incompetent; thus a cycle is begun that eventually causes dilation of the entire saphenous system.

Another mechanism for the development of varicose veins is incompetence of the perforating vein valves. When the calf muscles contract, blood is prevented from flowing through the perforating veins into the superficial system by closure of their valves. If a valve is not working properly, blood will flow from the deep veins into the superficial venous system. The flow of blood from the deep system into the superficial system diminishes the blood flow back to the heart, and it greatly increases the venous pressure in the leg. This increase of the venous pressure, termed venous hypertension, is the cause of many of the sequelae seen in chronic venous insufficiency, such as edema, stasis dermatitis, pigmentation from hemosiderin, and ultimately the development of lipodermatosclerosis and venous ulceration.

Secondary Varicose Veins

Secondary varicose veins can occur as a result of a superficial or deep venous thrombosis (DVT) or from an arteriovenous fistula with resulting high venous pressure. All of these conditions may cause venous dilation and lead to valve incompetence.

Contraindications

• Saphenofemoral junction or saphenopopliteal junction reflux.

• Reflux from deep system into superficial creates high venous pressure, making it difficult to obliterate vein.

• Veins larger than 0.6 cm in diameter.

• If the vein has a large diameter, it is difficult to obtain coaptation of intimal surfaces for permanent obliteration; it is more likely that a thrombus will develop within the lumen of the vein and recanalize over time.

• Some practitioners do inject these large vessels, but recurrence and complications are more common and phlebectomy might be a wiser choice of treatment.

• Arterial insufficiency.

• Ankle-to-brachial index less than 0.7 or other signs of inadequate arterial flow.

• Diabetic neuropathy.

• Acute superficial or deep thrombophlebitis.

• Massive obesity.

• Anticoagulation.

• Obstruction of the deep venous system.

• Severe systemic disease (especially collagen vascular disease, malignancy, or severe cardiac problems).

• Lack of mobility, such as seen in stroke, arthritis, or other musculoskeletal disorders.

• Unwillingness to comply with a program of compression.

• Acute febrile illness.

NOTE: The clinician should use caution in patients with asthma or numerous allergies (unless hypertonic saline is used) to avoid potential hypersensitivity. Age is not a contraindication if the patient is active and has reasonably good skin turgor.

Equipment

• Camera for pictures (optional).

• Examination table. (A power table is helpful but not mandatory.)

• Patient stand. (The examination can be performed more optimally if the patient’s feet are 24 inches off the floor. Usually this requires a made-to-order stand that includes a strong railing. The stand can be used for both examination and treatment.)

• Good lighting. (A gooseneck lamp is sufficient; however, some therapists use a more intense light source, such as a headlamp.)

• Magnification loupes (3×).

• Syringes (3.0 and 1.0 mL); 1/2-inch, 30-gauge needle.

• Handheld Doppler probe.

• Sclerosing solution:

• Sodium tetradecyl sulfate (preferred by the author) in dilutions of 0.2%, 0.5%, 1.0%, and (rarely) 3.0%.

• Hypertonic saline in a dilution of 18.7% is also commonly used (and preferred by the editor). It can be prepared by injecting 2 mL of 2% lidocaine into a 30-mL, multiple-dose vial of 23.4% saline (0.5 mL of this solution is injected per site). It is sterile and can be left diluted for up to 12 weeks.

• Polidocanol is another common sclerosant but is not approved by the U.S. Food and Drug Administration (FDA).

NOTE: The assistant should have 5 to 10 1-mL syringes drawn up for use, depending on the sclerosant and the quantity of veins to be injected. Each agent has benefits and risks. Hypertonic saline is effective and there are no allergic reactions; however, it is painful and the risk of extravasation necrosis of the skin is significant (Box 92-1). Polidocanol (0.05% to 3%) is a weak sclerosant, but it works well on small veins. Allergic reactions are possible but rare, and it is not FDA approved (in phase III trials). However, it is frequently used in the United States even now (Box 92-2 and Table 92-3). Sodium tetradecyl sulfate is medium in potency and relatively painless, but it must be injected carefully to avoid skin necrosis. Allergy and anaphylaxis can occur, although this is rare (see Table 92-1).

• Cotton balls with isopropyl alcohol or benzalkonium chloride (Zephiran).

• Tape (1 inch wide). (Some patients require paper tape.)

• Compression stockings. Some clinicians stock them in the office. Patients can also be given a prescription to purchase them at a medical supply store (with proper measurements noted on the prescription) or they may be fitted at certain retailers. Pantyhose, full-length stockings, thigh-high stockings, or calf-high stockings are selected based on the areas being injected. Rubber gloves are helpful to apply the stocking(s).

• Elastic wraps (4 to 6 inches wide; e.g., Ace bandages).

• Nonsterile gloves.

Box 92-2 Polidocanol Description

Polidocanol was originally developed as a topical anesthetic under the trade name Sch 600.

There are three groups of local anesthetics:

1 Esters: procaine, benzocaine, tetracaine

2 Amides: lidocaine, prilocaine, mepivacaine, procainamide, dibucaine

3 Urethane: polidocanol

It is generally classified as a weak detergent solution.

It should be diluted with distilled sterile water.

Patients should be warned about an Antabuse–alcohol reaction.

Elimination half-life is 4 hours, with 90% elimination within 12 hours; it does not cross the blood–brain barrier.

Only gold members can continue reading. Log In or Register to continue

Related

Stay updated, free articles. Join our Telegram channel

Tags: Pfenninger and Fowlers Procedures for Primary Care Expert Consult

May 14, 2017 | Posted by admin in GENERAL & FAMILY MEDICINE | Comments Off

Full access? Get Clinical Tree

Get Clinical Tree app for offline access

Get Clinical Tree app for offline access