Physical Therapy in the Treatment of Venous Leg Ulcers: Biophysical Mechanisms
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Index: WOUNDS. 2012;24(5):138–145.
Abstract: The present study sought to estimate the hemodynamic effects inside wounds after applying infrared thermography. Clinical results were analyzed to evaluate any correspondence with hemodynamic events occurring inside the wounds. Methods. Group 1 consisted of 20 patients with venous leg ulcers (12 women, 8 men). Patients from group 1 received 1 high-voltage stimulation (HVS) procedure. Group 2 consisted of 23 patients (16 women, 7 men). Patients from group 2 received 1 ultrasound (US) procedure. Group 3 consisted of 21 patients (13 women, 8 men). Patients from group 3 received 1 low-level laser therapy (LLLT) procedure.
Group 4 consisted of 23 patients (15 women, 8 men). Patients from group 4 received 1 compression therapy (CT) procedure. Group 5 consisted of 19 patients (11 women, 8 men). Patients from group 5 received 1 quasi-CT procedure. Infrared thermography was used to monitor arterial hemodynamic effects for each ulcer. Infrared thermography, based on analysis of wound surface temperatures, was used to reflect normal or abnormal arterial circulation in capillaries. The average and maximal temperatures before and after each physical procedure were measured 5, 10, 15, and 30 minutes afterward. Results. The application of HVS and LLLT did not change the temperature inside the wounds. A significant temperature increase was noted after application of US and CT. The quasi-CT induced a thermal effect (only for a few minutes), but was not as intense as the effect of the compression stockings. The measurements showed a prolonged and steady thermal effect. Conclusion. The hemodynamic effect (improvement of arterial microcirculation inside the venous leg ulcer) is one of the most significant biophysical mechanisms of healing after clinically efficient compression therapy. Hemodynamic reactions are not basic mechanisms of high voltage stimulation and ultrasound therapy during the healing of venous leg ulcers. Computed thermography is a simple and useful tool to measure hemodynamic effects in wound healing.
Management of venous leg ulcers should be based on understanding pathophysiologic abnormalities. The pathophysiology of venous ulceration is controversial1; however, it is believed that these ulcers result from venous occlusion or valvular incompetence and subsequent superficial venous hypertension. Venous leg ulcers occur as a result of underlying venous disease where damage has occurred to the superficial, deep, or perforating veins. Although the etiology of venous ulceration is unclear, it has been suggested that ulceration results from increased intraluminar pressure in the capillaries, which results in fibrin deposition around the capillaries. White blood cells are activated and release proteolytic enzymes that cause further tissue destruction. The alternative “trap” hypothesis proposes that fibrin and macromolecules eventually leak into the dermis where they bind with growth factors, making them unavailable to the tissue repair process.
More recent theories have associated the pathogenesis of venous ulcers with microcirculatory abnormalities. Physical therapies improve arterial blood circulation inside the wound2–4 by reaching capillaries near the surface, which transports heat via blood flow into deeper layers and increases capillary blood flow near the surface of the skin, while expanding the blood flow areas. Better blood microcirculation produces a therapeutically usable field of heat within the tissue and accelerates the healing process.
Based on the results of a clinical study,5 the authors concluded that compression therapy (CT) is the most effective physical method in venous leg ulcer healing.