Estimulação elétrica de alta voltagem incrementa a cicatrização de lesões cutâneas crônicas: análise de seis casos High voltage pulsed stimulation increases cicatrization of chronic cutaneous ulcers: analysis of six cases Estimulación eléctrica de alto voltaje incrementa la cicatrización

Endereço para correspondência: Maísa Soares Gui – Avenida Limeira, 901 – Caixa Postal 52 – CEP: 13414-903 – Piracicaba (SP), Brasil – E-mail: maisa_gui@yahoo.com.br Apresentação: dez. 2012 – Aceito para publicação: ago. 2013 – Fonte de financiamento: nenhuma – Conflito de interesses: nada a declarar – Apresentação em evento científico: II Congresso Brasileiro de Fisioterapia (Intercobraf) – Parecer de aprovação no Comitê de Ética no 08-3/019. Resumo | O tratamento de úlceras cutâneas por estimulação elétrica tem crescido na prática clínica, no entanto, faltam estudos que investiguem a efetividade desse recurso em acompanhamento prolongado ou até que ocorra a cicatrização completa das lesões. Assim, a estimulação elétrica de alta voltagem (EEAV) foi aplicada em úlceras cutâneas crônicas com o objetivo de reduzir a área da lesão. Para tanto, participaram do estudo quatro homens que apresentavam seis úlceras cutâneas que receberam a EEAV (fase=15ms; F=100 Hz; T: 100 a 150 V; fases gêmeas), 2 vezes por semana, durante 30 minutos. O eletrodo com polaridade negativa foi colocado sobre a lesão e o positivo no trajeto vascular. As úlceras foram avaliadas pré e pós-intervenção por meio da fotogrametria, sendo calculada a área da lesão. Como resultado, observamos o fechamento completo da lesão nos sujeitos I e II (área de 4,66 cm para 0 após 21 sessões e de 1,74 cm para 0 após 16 sessões, respectivamente). O sujeito III obteve redução de 93% na área da lesão direita (de 2,02 para 0,14 cm) e na esquerda de 80,40% (de 2,50 para 0,49 cm2), após 100 sessões. No sujeito IV ocorreu o fechamento completo da lesão sacral (de 10,74 cm para 0) e a redução da lesão isquiática de 11,01 para 2,43 cm2, após 75 sessões. Desse modo, concluímos que a EEAV facilitou o processo de cicatrização das úlceras estimuladas, pois as áreas de todas as úlceras apresentaram diminuição superior a 78%, havendo cicatrização completa em três delas.


INTRODUCTION
Skin injuries present several etiologies and can become chronic when the tissue formation is interrupted or destroyed by repeated damage or if one or two chemical or cellular elements of the healing process are deficient 1 .
In Brazil, the prevention work in general does not happen or it is not properly carried out, therefore the prevalence of pressure ulcers in hospitals is extremely high 2,3 .Difficulty in treatment success is increased due to problems like deficiencies in the patient's nutritional status and in mobility 4 .
In 211 assessed risk patients, a 39.8% incidence of pressure ulcers was seen 5 .Also, higher rates of morbidity and mortality were found in these patients 1,6 .These results demonstrate the urgent need to create a program for the prevention and treatment of these wounds.
Not only the wounds of this etiology, but also the chronic injuries, present a relevant repercussion for the health of individuals at risk 7 .The slow healing in vascular ulcers has serious consequences for people, including pain, loss of job, and quality of life decrease 8 .
Depending on the injury level and depth in the tissues, the ulcers may bring complications like osteomyelitis, septicemia, or death.Besides the financial losses caused to patients and their relatives, the problem also has psychological disorders and hinders or makes it difficult for the participation of the subject in rehabilitation programs 9,10 .
Skin ulcer treatment using electrical stimulation has been growing in the clinical practice 11 , because it is a low-cost option and it may accelerate the healing process, reducing treatment expenses 12 .In studies using animals, it has been suggested that electrical stimulation improves wound healing, increasing growth factors in the epidermis and dermis 13 .
Regan et al. 14 , in a systematic review, presented evidence supporting the use of electrical stimulation to accelerate tissue repair rate in pressure ulcers.Among these resources, the high-voltage pulsed stimulation (HVPS) promotes the acceleration of the healing process in chronic ulcers of several etiologies 7,[15][16][17][18] , due to its significant effects to improve circulation 15 .
However, the majority of studies 7,16-19 followed-up the wounds for a short period (4-6 weeks of stimulation) 14 , and they did not try to investigate if this resource would lead to the complete lesion healing.Thus, we observed the evolution of the areas of chronic skin ulcers during the treatment with HVPS for 12 months and/or until its complete cicatrization.

Study outline
One case series describing the treatment results of six skin ulcers by HVPS, followed-up for 12 months, is presented in this study.
series.The inclusion criterion consisted of skin lesion appearance of any etiology, and infection in the lesion to be treated was the exclusion criterion.

Ethics procedures
This study was carried out according to the resolution 196/96 of the Brazilian National Health Board, approved by the Research Ethics Committee, under protocol 08-3/019.The evaluation and intervention using HVPS was done in the Physical Therapy School Clinic.All subjects were informed about the experimental procedures and signed the free informed consent to take part in this study.

Intervention
The suggested treatment was performed with the Neurodyn High Volt ® high-voltage electrical stimulation equipment (IBRAMED ® , registration in M.S. 5122).
Intervention consisted of HVPS application (phase=15 ms; F=100 Hz; T: 100-150 V; twin phases) with a similar protocol to that described by Houghton et al. 7 , the treatment was carried out twice a week, and each session lasted 30 minutes.
The negative polarity active electrodes were wrapped up in sterilized gauze moistened by saline, being later placed and fixed with an adhesive tape inside the wound.The 10×18 cm self-adhesive dispersive electrode (VALUTRODE ® Axelgaard Manufacturing Co., Ltd.) was fixed with positive polarity in the vascular path of the area.After every 5 minutes of treatment, the gauze under the electrodes was humidified with saline using a sterilized syringe as support.
At the end of each session, asepsis of the electrodes was carried out for later use.The polarity of electrodes remained the same throughout the treatment.
It is worth mentioning that each subject had his/her own electrode kit.It was not used with any other medicine treatment in the treated ulcer, it was only necessary to apply, on a daily basis, sunflower oil -essential fatty acids, which are derived from linoleic acid -for skin hydration, and gauze for protection.This procedure was adopted because all patients were already making use of such oil for years.

Evaluation method
The treatment evolution was analyzed by means of standardized photographic records for the wound area analysis, in squared centimeters.Hence, a digital camera was used (Panasonic ® Lumix, model FX12; 7.2 megapixels), being placed at 40 cm from the ulcer, perpendicularly, including in the picture a millimeter-scaled ruler touching the skin.
After the recordings, the images were processed in the software used by Davini et al. 19 , which calculates the area.A 1-cm distance is marked in the ruler and reported to the software that automatically calculates it in pixels (DPixels).

Data analysis
Data presentation was performed in a descriptive manner to each subject individually.This procedure was adopted because the ulcers have different etiologies and the number of HVPS sessions may vary between the subjects.

Subject I
A 73-year-old patient presenting a superficial venous ulcer, plain crater, in the anterior region of the right tibia, with partial loss of the skin continuity involving epidermis and dermis, since a year.In the initial evaluation, the wound had a 4.66 cm 2 area.After 10 sessions, it reduced to 0.65 cm², and the complete healing was obtained after 21 sessions (Figure 1).

Subject II
Twenty-six years old, paraplegic, with pressure ulcer in the sacral area, for 1 year, classified as degree II (plain crater).In the initial photogrammetry, it registered an area of 1.74 cm 2 .After 10 sessions, there was a reduction of the injury lesion to 0.75 cm 2 , and the complete closure happened after 4 months using HVPS, totaling 26 sessions (Figure 2).

Subject III
Fifty-five years old, quadriplegic, presented two sciatic pressure ulcers since 8 years ago.The right ulcer had a 2.02 cm 2 area in the beginning of the treatment, which in the 44th session diminished to 0.51 cm 2 and in the 100th session to 0.14 cm 2 (93% reduction), as seen in Figure 3. Also, it should be mentioned that the lesion was classified as degree IV (deep crater with extensive destruction).
The left sciatic pressure ulcer was also a degree IV lesion, which suffered three surgical intervention attempts (graft), with no success.It presented an initial area of 2.50 cm 2 and after the 44th session, this surface reduced to 1.53 cm 2 and in the 100th session to 0.49 cm 2 (80.40% decrease).
It was also seen that there was an increase of the lesion area between the 48th and 50th sessions from 1.53 to 2.07 cm 2 .In such a period, the treatment was suspended for 2 months due to an infection in the lesion (Figure 3).

Subject IV
Sixty-six years old, triplegic due to cerebrovascular accident, presents two pressure ulcers being one sacral and the other sciatic to the right, with 4 years of existence.The sacral lesion, degree (deep crater), had an initial area of 10.74 cm 2 , and after 37 sessions it decreased to 3.79 cm 2 , reaching complete healing after 75 sessions (Figure 4).
The sciatic ulcer, degree III, presented in the initial evaluation an 11.01 cm 2 area, which, after 34 sessions, decreased to 2.94 cm 2 and by the end of the 75th session, to 2.82 cm 2 (74.38% decrease).

DISCUSSION
In this study, we could notice complete closure of the three wounds and an important reduction of other three lesions treated with HVPS.The ulcers had different etiologies and classifications; therefore, there were distinct responses as to cicatrization speed/time and percentage.Furthermore, the follow-up of these patients for a short period enabled a better comprehension of the lesion reaction to stimulation.
Wound classification comprises stage I-IV with regard to depth of tissue compromising instead of lesion severity 20,21 .Cicatrization happens with the support of granulation tissue, by second intention, and the ulcer improvement or worsening evaluation is carried out by measuring its dimension 22 .Thus, we verified  that superficial ulcers presented an accelerated healing speed, because in subjects I and II (degree II) there was complete closure of the lesion after 21 and 26 sessions, respectively, while the sacral lesion healing of subject IV (degree III) was achieved after 75 sessions.
In subjects with degree IV ulcers, there was a decrease from 74 to 93% of the lesions areas; however, it happened more slowly.This reaction is somehow expected, since cicatrization by second intention occurs from inside to outside the ulcer and, due to the fact that these lesions were deep, changes would be seen in depth and not in the lesion area 20 .This fact could be seen by the visualization of the photographed pictures, but it was not measured in this study and, therefore, it is a limitation of this work.
All lesions that did not completely heal were in the gluteal fold, that is, an area with much humidity and contamination and also a constant pressured place, which are caused by shearing and compression strengths.
Studies have indicated an improvement preferentially in pressure ulcers 19 .Griffin et al. 17 observed, after 20 consecutive stimulation days, an 80% decrease of pressure ulcers places and of 52% in the control group.The protocol consisted of negative polarity use in the lesion (60 minutes).Unger et al. 16 , however, performed polarity inversion of the electrodes, initiating by negative and after 6 days of treatment, it changed to positive.Eight of the nine stimulated patients had an 88.9% healing, while in the control group three of the eight subjects had a 37.5% improvement.In another study 23 , stage II ulcers presented increment of the cicatrization with significant increase in the granulation tissue concerning the control group, after 6 weeks of treatment.
However, HVPS in vascular chronic ulcers in the leg produced a reduction in the size of wounds when compared to those that were considered treated 7 .A similar result was seen in this study, as in one of the subjects who had his/her lesion healed, the etiology was venous.On the other side, in another study 24 , nine patients had their venous ulcers healed or reduced, while four had them increased, and the authors reported the reason for this as the incidence time of the lesions.Concerning time of the lesion, it is worth mentioning that the unhealed ulcers were aged between four and eight years old, which is a higher time than those presenting complete cicatrization (one year).
We also saw a fast lowering of the lesion areas in the beginning of treatment, which may be stabilized.This decrease in healing speed may be explained due to the better reaction to the polarity inversion according to the phases in which the tissue repair is found than in the maintenance of the same polarity until the treatment ends 25,26 .
Recio et al. 27 started the HVPS treatment with negative polarity and then changed it weekly, thus achieving complete healing of chronic pressure ulcers (existent from 11 to 14 months).
The tissue repair is divided into four phases: hemostasia, inflammation, proliferative, and remodeling 1 ; therefore, Sussman and Byl 26 preconized the beginning of the treatment with negative polarity, changing it every 3 days in the proliferation phase, and in the remodeling stage, it was altered every day.It is quite probable that the polarity inversion be necessary in these chronic and deep lesions, in order to not slow the cicatrization process.
The mechanisms for which the HVPS reaches positive healing results have not been well established yet.The current, despite its polarity (single-phase wave) 28,29 , passes through the skin with despicable thermal and electrochemical effects and the highest current density is available for target tissues, affecting the cellular level directly 30 .In addition, it can be efficient to contain and absorb acute edemas, to fasten the dermal and sub-dermal tissues repair, and to control pain 31 .Other aspect that should be considered is galvanotaxis, which is the migration of electric-charged cells with regard to an electrical field of opposed polarity.As to skin cicatrization, the electrical fields exogenously applied with the same size as those found in lesions, promote migration of human keratinocytes for the cathode 32 , which is the polarity used on the lesion in this study.
Besides its circulatory and regenerative actions, the HVPS presents bactericide action 18 , because it leads to local changes in the pH, electrochemical changes in the injured tissue, and recruitment of anti-microbial factors of the organism.
Endogenous electrical fields from a wound may act as an important guide of stimulus for the migration of epidermal stem cells from their niches to the interior of the wound, making healing easer 33 .However, it has been suggested that the cascade of events that happen during and after the cicatrization inflammatory/proliferative process may have suffered an interruption in the chronic wound cases, and electrical stimulation of these wounds produces effects that are able to restart or start the repairing phase 34,35 .In addition, the electrical stimulation can accelerate cicatrization, reducing inflammation, increasing angiogenesis, and advancing to remodeling stages 36 .
The increase in microcirculation around the inframalleolar ischemic wounds would explain the quick decay in the area of 11 ulcers stimulated by HVPS 37 .Furthermore, it was verified that there is an increase of the oxygen transcutaneous pressure and capillary perfusion in the edge of venous ulcers, which indicates that HVPS can result in oxygenation and cicatrization due to the increase of tissue perfusion 38,39 .
Finally, the efficacy of HVPS treatment may be associated with lesion etiology, occurrence time, wound location, and polarity of electrodes.Therefore, clinical perspectives of our results reinforce the extensive need for multidisciplinary treatment when handling this pathology.Considering the limitations of this outline as to the generalization possibility, the next step should be HVPS intervention use in a randomized and representative sample in patients with skin ulcers, determining the polarity based on cicatrization phase and associating it with conventional treatments.

CONCLUSION
From the experimental conditions that were performed, it could be verified that the areas of all ulcers stimulated by HVPS decreased and there was complete healing in three of them.