Treating Venous Stasis Ulcers In The Lower Extremity

Author(s): 
By Mark Beylin, DPM

Chronic venous insufficiency is a significant disease that affects as much as 25 percent of the population in the United States. It is also a condition commonly treated by podiatric physicians. The condition results in blood pooling in the venous system of the lower extremities (see “A Guide To Normal Venous Anatomy And Physiology below). Venous stasis ulcers are the end stage of chronic venous insufficiency. In order to treat venous stasis ulceration, one must have a clear understanding of the pathophysiology of venous disease. Most of the vein problems that occur are due to increased pressure in the venous system. Venous insufficiency and subsequent hypertension are caused by valvular incompetence in the high-pressure deep venous system, low-pressure superficial venous system or both. Dilation of the veins is the primary problem. When the veins dilate, the valves are separated from each other. This causes a back flow of blood. When veins lose their functional capacity, gravity works against the flow of venous blood in the lower extremity. When one is walking, the blood flow is generally normal even through the incompetent veins and muscle contracture circulates blood out of the leg. On the contrary, when one stands, there is a reverse flow in the incompetent vein and a back flow occurs. This gets in the way of venous drainage and eventually results in an elevation of venous pressure. When valves of the perforating veins become incompetent, high-pressure blood from the deep venous system flows towards the skin, producing hypertension in the superficial veins.2 This process leads to the leaking of fluid from small veins makes into the surrounding tissues. This causes edema and characteristic discoloration. This is subsequently followed by an impaired exchange of nutrients and wastes between the arterial and venous systems. A Guide To Normal Venous Anatomy And Physiology Venous stasis disease has been a challenging problem to treat for centuries. Fabricius, an Italian surgeon, was the first to recognize the structure and function of the venous valve, which lead to the understanding of the pathophysiology of venous stasis ulcers. With this in mind, it is important to have a strong grasp of normal venous anatomy and physiology. The great saphenous vein is the main superficial vein in the leg. It begins just anterior to the medial malleolus and rises obliquely and posteriorly. The saphenous vein is joined by the posterior arch vein just below the knee. The superficial anterior vein in the lower leg and the anterolateral and posteromedial veins in the thigh join the saphenous vein near the inguinal ligament. The lesser saphenous vein is located posterior to the lateral malleolus advancing upward, lateral to the Achilles tendon. As it reaches the popliteal space, it is situated between the heads of the gastrocnemius muscle. The communicating veins are the connection between the superficial and deep veins. Blood flows through one-way valves from the superficial venous system to the deep venous system of the lower extremity. In the calf, the deep veins are paired and accompany their corresponding arteries with venous tributaries intertwining over the surface of the artery. At the knee, the veins usually join to form the popliteal vein. The function of the deep veins is to carry blood from the muscles of the extremity providing carrier function for the calf muscle pump. The calf muscle veins are covered with a tight fascia, similar to that of an elastic support stocking. This prevents dilation of the deep veins in contrast to the superficial veins, which are contained within loose non-supportive tissue. The popliteal vein becomes the superficial femoral vein. As far as physiology goes, the calf muscle pump cycle has two phases of blood pumping: systolic and diastolic. During the systolic phase, contraction of the calf muscles compresses the blood within the deep venous system, pumping it in the direction of the heart. Valves of the communicating veins act as the bridge between the deep and superficial systems. These valves are closed as they prevent the back flow of venous blood. At this time, the pressure within the deep venous system can reach 120 mm Hg.1 During the diastolic phase of the muscle pump, the muscle relaxation allows the deep venous system of the calf to refill.

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