Lojze Vodovnik

Treatment of chronic wounds by means of electric and electromagnetic fields

Subjects with spinal cord injury are often distressed by pressure sores, which usually appear after prolonged pressure (wheelchair, bed) across the soft tissue which has already lost sensibility and has diminished microcirculation. The healing ability and its dynamics depend on the state of the subjects overall health. Consequently, evaluation of a particular treatment requires careful consideration of as many as possible of the parameters relevant to healing and an adequate criterion for assessing the state of the pressure sore. Bearing in mind these two circumstances, the results of a multicentre clinical study are analysed. The aim of the study was to test two hypotheses: first that healing is faster when sores are also treated by electric currents (ECs) (in addition to conventional treatment); and secondly that there exist differences in the efficiency of the treatment if direct or low-frequency pulsed currents (FES parameters) are applied. The data analysed show that pressure sores are likely to heal twice as fast when treated with low-frequency pulsed currents. EC seems to improve the healing rate in cases where the natural healing mechanisms of the body are not sufficient (chronic wounds, older subjects).

Treatment of chronic wounds by means of electric and electromagnetic fields part 1 literature review

The healing of a cutaneous wound is accompanied by endogeneous electrical phenomena. Not knowing whether they represent merely a side-effect of the physiological processes which take course during healing or whether they play a much more important role as mediators of healing, externally applied electricity was examined as a therapeutic tool for the enhancement of natural regenerative processes. In the present review a historical literature survey dealing with human applications of electric current for wound healing acceleration is given. It presents a complete palette of heterogeneous studies, differing in the parameters of applied electric current, in delivery modes as well as in the types of wounds being stimulated. Because of all these differences, comparing the efficacy of the described methods is difficult and could hardly be objective. Therefore greater stress was laid upon the discussion concerning the problems in designing clinical studies (size of the sample observed, control group, ethics of the procedures), rationales for the employment and possible underlying mechanisms of particular methods, and problems of evaluating their efficacy. In spite of the extensive work performed in the field of electrical wound healing we remain only part way towards explaining the mechanisms by which electricity reinforces the regenerative capabilities of injured tissue as well as only part way towards the selection of the optimal stimulation method from among the published reports.

Tumor treatment by direct electric current-tumor temperature and pH, electrode material and configuration

Electrotherapy with low-level direct current has been suggested as an effective regional cancer treatment. A great variety of electrode materials, their placement with respect to tumor (i.e. electrode configurations) current levels and therapeutic schedules have been employed to date. In our paper the impact of electrode materials and configurations was studied, employing the same treatment parameters and schedule, on the subcutaneously grown solid tumor fibrosarcoma SA-1 in A/J mice. The effect of electrotherapy was assessed by tumor volume determination on each consecutive day and by determination of the extent of necrosis along the tumors greatest diameter immediately after electrotherapy, 24, 48 and 72 hours later. The development of tumor necrosis after electrotherapy application differed for different electrode configurations. Intratumoral temperature and pH were measured before and after the application of electrotherapy in all electrode configurations used. Irrespective of the electrode configuration the intratumoral temperature was unchanged by electrotherapy. Considerable variations in pH were revealed for configurations where one electrode was inserted into the tumor, whereas in configurations with both electrodes outside, the tumor pH remained unchanged by electrotherapy. Electrodes made of platinum, platinum (90%) :iridium (10%) alloy, gold, silver and titanium were used for current delivery, and significant tumor growth retardation was achieved irrespective of electrode configuration and material (p< 0.001, Mann-Whitney Rank-Sum test). In addition to possible toxicity arising from dissolved metal ions and products of electrochemical reactions, which may result from electrolysis, direct effects of current on tumor and immune cells are suggested.

Modified cell proliferation due to electrical currents

In view of the evidence that electrical currents may enhance healing of chronic wounds and retard tumour growth it is suggested that these currents normalise cell proliferation. Additional support to this contention is given by two reports: one on healing of pressure sores in man and one on tumour growth retardation in mice. The effect of an ionic environment on the cell cycle is analysed. Finally a hypothesis attempting to explain the normalising effect of electrical currents on cell proliferation is proposed. It is known that non-dividing cells, e.g. mature neurons, have high transmembrane potential (TMP) whereas fast-dividing cells, e.g. cancerous cells, have low TMP. When a cell is exposed to an electrical field, one side of the cell becomes hyperpolarised while the opposite side is depolarised. Assuming a nonlinear relationship between TMP and the transmembrane ionic currents, it can be shown that in non-dividing cells their high TMP is lowered; whereas in cells with a high division rate, their low TMP is raised due to cell exposure to the external electrical field. These alterations in transmembrane potential could contribute to the normalisation of abnormal cell proliferation.

DC electrical stimulation for chronic wound healing enhancement Part 1. Clinical study and determination of electrical field distribution in the numerical wound model

Abstract Notwithstanding several past clinical studies demonstrating the beneficial impact of electrical stimulation with steady direct current on the healing of chronic cutaneous wounds, the basic mechanisms underlying its effects on regenerative processes remain to be elucidated and the stimulation regime optimized. In the present study, an attempt is made towards the optimization of steady direct current stimulation of wound healing with respect to the shape and positioning of stimulation electrodes. The effects of direct current stimulation on wound healing were studied in a double-blind clinical trial involving fifty patients with spinal cord injuries, suffering from pressure ulcers. The therapeutic effect of electrical stimulation was found to depend on the positioning and shape of the electrodes. Healing of pressure ulcers was significantly enhanced by direct current, with the positive stimulation electrode overlaying the wound surface and the negative electrode placed on intact skin around the wound. By contrast, stimulation by the second type of electrode configuration - which assumed positioning of both stimulation electrodes on intact skin at the opposite sides of the wound - had only a non-significant effect on pressure ulcer healing. Numerical modelling showed that direct current stimulation using two types of electrode arrangements induced different electric field distributions in the stimulated tissue in the wound area. Endogenous electric conditions in the skin were closely approached with external electrical stimulation when the wound surface was covered with the positive stimulation electrode, while the negative electrode surrounded the wound. With such stimulation, highly significant acceleration of wound healing was observed in the clinical study, leading to the assumption that endogenous electrical phenomena in injured skin are not just side effects, but play an active role in healing. The agreement of the externally induced electric field with the endogenous electric field distribution in injured skin was adopted as the basis for optimization of direct current electrical stimulation for wound healing enhancement.

Low frequency pulsed current and pressure ulcer healing

In spite of the extensive clinical work reported in the area of electrical wound healing, electrical stimulation to augment chronic wound repair is still far from being widely accepted in clinical practice. Problems in designing clinical studies (size of the sample observed, control group, ethics of the procedure), evaluating treatment efficacy, rationales for use of the treatment, and unknown underlying mechanisms contribute to the aforementioned fact. In the present study, the authors evaluated low frequency electrical current for its beneficial effects in pressure ulcer management. Seventy-three spinal cord injured patients with 109 pressure ulcers participated in the study. Patients were randomly assigned to a control group receiving conventional treatment of their ulcers, or to a stimulation group, in which the ulcers were additionally treated with low frequency pulsed current. A comparison of the two groups showed significantly higher average healing rate for the stimulated group. Patients from the control group had the opportunity of crossing over to the stimulation group after the required control period of four weeks. This group (the crossover group) was analyzed separately. In all but one ulcer out of 20, an improvement in the healing process was observed after electrical stimulation was initiated. >

Anti-tumor effect of electrotherapy alone or in combination with interleukin-2 in mice with sarcoma and melanoma tumors

Electrotherapy with direct current (DC) was performed on two murine tumor models, fibrosarcoma SA-1 and melanoma B16. Three Pt/lr cathodes were inserted directly into the subcutaneous tumors and two anodes subcutaneously in the vicinity of the tumor. Significant tumor growth delay was achieved after electrotherapy and was dependent on DC intensity (0.6, 1.0, 1.4 and 1.8 mA). Melanoma B16 tumors were more sensitive to electrotherapy than SA-1 tumors. In order to enhance the antitumor effect of electrotherapy, combined treatment with interleukin-2 (IL-2) was performed. When both therapies were combined significant tumor growth delay and also higher curability rate was achieved. The results imply that electrotherapy can be an effective antitumor therapy and that the effects can be enhanced with additional IL-2 therapy.

Some properties of spastic ankle joint muscles in hemiplegia.

Patterns of stretch reflex activities provoked by sinusoidal oscillations at the ankle joint were studied in hemiplegic patients. Three different patterns regarding tonic and phasic reflex activity were found to be typical for these patients. Rather than length-dependent inhibition, known from paraplegic and multiple sclerosis patients, a neutral effect or facilitation of stretch reflex was observed. The resistance to these movements was also studied at different muscle lengths. It was proved that the resistance to passive movements is highly dependent on the muscle length at which it is tested. It is therefore suggested that the value of resistance together with the muscle length should be documented.

Tumor Treatment by Direct Electric Current: Computation of Electric Current and Power Density Distribution

Electrotherapy by direct electric current was shown to have an anti-tumor effect in different animal tumor models and in clinic. Information on the current density distributions in the tumor, surrounding tissues, and its differences in the different electrode configurations used in our previous studies could be useful in future studies of electrotherapy mechanisms. Therefore, a three-dimensional, anatomically based, finite element model of the mouse with a subcutaneous tumor was built. Different types of electrotherapy, i.e., different electrode configurations, were modeled by applying appropriate boundaq conditions in the grid points. The magnitude of current density in anodic/cathodic electrotherapy is 50 times higher in the middle and 10 times higher on the edge of the tumor when compared to the “field” electrotherapy. The results of the computation show that the effects of the electrotherapy on tumor growth, which were similar in terms of tumor growth delay in all three configurations, are not directl...

Local Treatment of Murine Tumors by Electric Direct Current

Low-level direct current (0.2–1.8 mA) was demonstrated to be an antitumor agent on two different murine tumor models (fibrosarcoma Sa-1 and melanoma B-16), and has been suggested for regional cancer treatment. Its antitumor effect was achieved by introduction of single or multiple–array needle electrodes (Pt-Ir alloy) in the tumor and (an)other electrode(s) subcutaneously in its vicinity. The electrode inserted in the tumor was made anodic (anodic electrotherapy, ET) or cathodic (cathodic ET). In control groups, animals were subjected to exactly the same procedures with needle electrodes inserted at usual sites without current. In single-stimulus ET performed after the tumors have reached approximately 50 mm3 in volume with 0.2, 0.6, and 1.O mA for 30, 60, and 90 min, cathodic ET exhibited better antitumor effect than anodic ET. In both cases and at all ET durations, the antitumor effect depended proportionally on the current level applied. The antitumor effect was evaluated by following tumor growth and ...