ABSTRACT
BACKGROUND: Chronic wounds are life-threatening in people with diabetes. Some studies show that electrical stimulation (ES) can help wounds heal, while others do not. But, ES is usually applied using a two-electrode system, where current distribution is greatest in the center line between the electrodes. In the present study, a three-electrode system (three-channel ES) was developed. Current dispersion on the skin and in the quadriceps muscle was compared between the conventional two-electrode and three-electrode systems in controls and tested for its ability to heal chronic wounds in people with diabetes. METHODS: In controls, current was delivered via a biphasic sine wave at a frequency of 30 Hz and pulse width of 100 microseconds. Stimulation electrodes 5 cm x 5 cm and 5 cm x 10 cm were placed at 10 cm and 15 cm separation distances above the quadriceps muscle. Skin currents were measured using five pairs of surface electrodes positioned in five separate locations on the skin. Muscle currents were measured using three pairs of needle electrodes positioned in three different locations in the muscle belly. In chronic wounds in eight subjects with diabetes, stimulation was applied for 1 month, and healing and blood flow were measured. RESULTS: Current during three-channel ES was dispersed more evenly and more deeply than with conventional two-channel ES (P < 0.05). In wounds, there was almost complete healing in 1 month, and current was uniform in the wound. CONCLUSIONS: Three-channel ES is more effective than two-channel ES in terms of better current dispersion across the skin and penetration into tissue and will probably be better for wound healing.
Subject(s)
Diabetes Complications/therapy , Electric Stimulation Therapy/methods , Electrodes , Wounds and Injuries/therapy , Adult , Diabetic Foot/therapy , Electric Stimulation Therapy/instrumentation , Equipment Design , Humans , Middle Aged , Reference Values , Skin/physiopathology , Skin Physiological Phenomena , Skinfold Thickness , Subcutaneous Fat/anatomy & histology , Wound HealingABSTRACT
Electrical stimulation is commonly used for strengthening muscle but little evidence exists as to the optimal electrode size, waveform, or frequency to apply. Three male and three female subjects (22-40 years old) were examined during electrical stimulation of the quadriceps muscle. Two self adhesive electrode sizes were examined, 2 cm x 2 cm and 2 cm x 4 cm. Electrical stimulation was applied with square and sine waveforms, currents of 5, 10 and 15 mA, and pulse widths of 100-500 micros above the quadriceps muscle. Frequencies of stimulation were 20, 30, and 50 Hz. Current on the skin above the quadriceps muscle was measured with surface electrodes at five positions and at three positions with needle electrodes in the same muscle. Altering pulse width in the range of 100-500 micros, the frequency over a range of 20-50 Hz, or current from 5 to 15 mA had no effect on current dispersion either in the skin or within muscle. In contrast, the distance separating the electrodes caused large changes in current dispersion on the skin or into muscle. The most significant finding in the present investigation was that, while on the surface of the skin current dispersion was not different between sine and square wave stimulation, significantly more current was transferred deep in the muscle with sine versus square wave stimulation. The use of sine wave stimulation with electrode separation distances of less then 15 cm is recommended for electrical stimulation with a sine wave to achieve deep muscle stimulation.
