The effect of alternating and biphasic currents on humans' wound healing: a literature review

Although different types of currents, including bidirectional currents, have been used to promote healing, there is neither a summary about their effects nor consensus on best parameters to be used. The aim of this article is to provide an overview of current evidence on the effectiveness of bidirectional electrical stimulation on wound healing in accordance with the parameters used. Relevant articles were selected following a search of Medline, Cochrane, Embase, CINAHL, and PEDro for English, Spanish, Portuguese, Italian, or French articles published between 1980 and 2011. Ten trials and four case-series were found that deal with pressure ulcers, diabetic ulcers, venous ulcers, skin flaps, and amputation. Eight trials were of low-quality. Five of ten controlled trials found a statistically significant difference on wound healing, and another four trials found positive trends. Both of the two skin flap trials, one of two diabetic trials, and two of five pressure ulcer trials found a significant difference in bidirectional stimulated groups. Both TENS and NMES types of currents were used, but many parameters were not specified. In general, bidirectional currents appear to increase wound healing rates and reduce size of wounds, above all in skin flaps. However, there is a lack of well-designed studies on biphasic and alternating stimulation, and there is a need for improvement in description of parameters and in uniformity of nomenclature.