ISRAEL JOURNAL OF
VETERINARY MEDICINE
USE OF ELECTRICAL STIMULATION FOR WOUND
HEALING IN DOGS
Vol. 57 (2) 2002
H. Sumano, G. Goiz and V. Clifford
Department of Physiology and Pharmacology, School of Veterinary Medicine,
National Autonomous University of Mexico, Mexico City, 04510. Mexico.
Abstract
In a clinical trial using electrical stimulation for healing wounds, forty-four dogs of different
breeds and ages were treated. Lesions were graded into three categories according to
severity. They were treated by electrical stimulation with supportive therapy given only if an
underlying disease was present. These wounds, previously treated conventionally without
success, showed marked improvement. Only 3 (6.8%) patients had an outcome graded
poor, 4 (9.1%) were graded fair, and 37 (84.1%) did excellently. A positive correlation (r =
0.98) was found between severity of lesion and number of treatments needed. Most patients
with an underlying condition had a poor to fair outcome. Although no explanation as to the
mechanism of action of this treatment is advanced, this trial suggests that electrical
stimulation is highly effective in promoting wound healing.
Introduction
When skin is damaged, not only are epithelial cells destroyed, but also a large quantity of
collagen is also lost. This is important because collagen makes up approximately 75% of the
weight of the skin [3]. To stimulate skin healing, a variety of methods have been used, such
as the topical application of herbal remedies like Aloe vera extract [7,8], the use of soft laser
[9], natural honey [10], electromagnetic pulses [11] and fibroblast growth factor [12]. Even
though good results have been achieved by these methods, the customary approach remains
the prevention of infection using antibacterial and antiseptic agents [13, 14], and sometimes
hygroscopic powders [9]. However, these approaches may be of limited benefit, if an
adequate blood supply to the affected area is not promoted especially in severe cases such
as extensive burn injuries, diabetic ulcers, ischaemic flaps, necrotic wounds and large areas
of skin loss.
Reports within the last two decades have shown renewed interest in stimulating wound
healing using electricity. Reich and Tarjan [15] reviewed the use of electrical stimulation for
wound healing and noted the emergence of improved dose criteria. In addition, numerous
morphological and functional effects of electric stimulation have been identified, both at the
cellular [16] and at the tissue level [15, 17]. It has already been used to promote healing of
intractable skin lesions in man [18].
Promotion of healing is still mandatory to reduce treatment time if the underlying medical
conditions are dealt with effectively. Many chronic wounds can be healed provided the
appropriate dressings, growth factors and/or electro physical modalities are applied [4]. In our
laboratory, well-organized skin wound healing with increased wound strength in rats has been
obtained using a particular arrangement of electrodes around a lesion and an acupuncture
electric stimulator as the source of power [6, 17]. Subsequent trials using serial
histopathology [16] and electron microscopy evaluations [17] suggested that a well-organized
process of skin repair was obtained. Appearance of the healed wound resembled that of
unharmed, unmodified skin. A calculated dose charge of 0.4-0.8 Coulombs/cm2 was capable
of improving wound healing in various laboratory species and later in human beings [18].
Considering these favorable observations, it was decided to test the same procedure on
dogs; particularly on those pets whose owners sought an alternative treatment, and always
after having experienced a clear failure with orthodox procedures and drugs.
Materials and Methods
Forty-four dogs were studied for this report. The general description of the patients is
summarized in Table 1. Thirty-five subjects had various skin lesions and nine had seconddegree burns. None with third degree burns was included in this trial. All had previously
received conventional veterinary medical treatment with unsatisfactory results. Table 2 shows
the details of skin lesions and burns included in study subjects.
Patients were classified as grade I, II and III, according to the severity of their lesions
(surface area, depth of the lesion and infection) and their medical status, i.e., presence of
compromising conditions such as diabetes, malnourishment, chronic heart failure, renal
insufficiency, geriatric dogs and so forth (Table 3).
Drugs previously administered or applied to the subjects included topical and parentheral
antibiotics, as well as various wound dressings together with hygroscopic powder and
sometimes cutaneous antiseptic preparations.
The dogs were treated with electric stimulation using a WQ- 6F [57-6F] acupuncture
stimulator (China National Chemical Imports and Exports Co., Beijing, PR China), delivering
positive/negative squared shaped spikes of 300 mV, 67 Hz, with a current of 0.04 µA and a
calculated absolute charge density of 0.4-0.8 Coulombs/cm2. This apparatus delivers
switching polarities every other second. In each session, 30-40 min. lapses of electric
stimulation were applied via electrodes clipped to stainless steel acupuncture filiform needles,
0.30 to 0.5 mm in diameter x 30-50 mm in length. Needles were inserted subcutaneously
along the edges of the lesion and placed to form an almost complete closed peripheral circuit.
In cases where the lesion was extensive and/or patients would not accept the insertion of
needles, the affected area was covered with a single layer of gauze soaked in 10% (w/v)
saline solution. Current was delivered clipping the gauze with alligator clips randomly located
throughout the gauze, as far apart as possible, to allow current flow. Treatment was
administered either every other day or every three days, based on the severity of the lesion
and the compliance of the owner.
In some cases, in particular those classified as grade III, conventional medical support
therapy was continued as instructed by their veterinarian; for example: hydration, proper diet,
and insulin in two diabetic patients; better nutrition and vitamins in one undernourished dog;
diuretics, potassium and captopril in two dogs with chronic cardiac failure and adequate lowprotein diet in two dogs with chronic renal insufficiency. In all cases, improved hygiene:
bedding and housing were indicated. However, in no case were local antiseptics or
antibacterial agents (neither systemic nor local) administered. In five patients in the grade III
group fresh Aloe vera extract was applied immediately after each treatment [8] because their
wounds were liable to get dirty due to their location in the body. When wounds were clinically
infected, sterile 0.89% saline solution was used to physically remove pus and other organic
material as often as needed. Wounds were never closely covered with heavy dressings or
gauzes. Owners were advised to allow air contact and keep the dog indoor or confined
comfortably as much as possible, when outdoors, light dressings were used to minimize
airborne contamination. Only on four occasions restraining collars became necessary.
The end of the treatment was established when two colleagues (acting as independent
observers) agreed that full recovery was evident to all included the owner or when no further
progress was observed in the last two or three visits. At the end of the treatment the authors
and the owner, previously instructed in the scoring system, independently assessed the
clinical outcome as follows: poor: less than 50% recovery; fair: 60-90% recovery; and
excellent: greater than 90% recovery.
Results
Table 4 presents the cases treated, the number of days from the beginning of the medical
problem to their presentation at our facility and the number of treatments given. The results
were as follow: 37 (84.1%) patients did excellently, 4 (9.1%) were graded as fair and only 3
(6.8%) produced poor results.
Figure 1 shows a patient with an extensive wound as a result of an encounter with an
automobile. The wound had an approximate surface area of 50 cm2 comprising the dorsolateral area of the left hind limb metatarsus. This lesion was classified as a grade III wound
due to its large surface area and the loss of the full thickness of the skin exposing the
underlying muscle tissue. Previous medical approach included systemic antibiotic therapy, as
well as topical administration of a neomycin-based ointment and a hygroscopic powder.
Additionally, the owner was instructed to keep the wound covered at all times. The electrical
stimulation-based treatment was initiated coupling electrical stimulus to gauze soaked in 10%
saline solution as previously described. Figure 2 shows progress of wound healing by the 9th
session. Later, by session 14, needles were inserted circling the wound to speed up healing.
Figure 3 shows the wound with the needles inserted around it at session 18. Figure 4 shows
the results of the treatment after 27 sessions. Approximately 80% of the surface was fully
repaired, and fur covered it again. Outcome for this particular wound was regarded as
excellent.
Due to the variety of wounds dealt with as well as the extent of the damage observed in
some cases, the number of treatments required for obtaining a cure varied greatly. However,
when lesions were classified according to their severity as well as to the overall condition of
the patient, a closer statistical correlation between the lesion grade and the number of
treatments to total cure was obtained (r=0.98; Pearson correlation).
Grade I patients needed 8.4 + 2.3 treatments to obtain a complete healing, while grade II
patients required 10.6 + 4.08 treatments, and grade III patients required 41.38 + 6.58
treatments.
Mean elapsed time from the identification of the lesion to the first presentation of grade I
subjects at our facility was 11.8 + 4.49 days, while grade II and grade III patients had a mean
time of 15.44 + 8.58 days and 24.5 + 5.21 respectively. A positive correlation was found
between the severity of the lesion and the time of their first visit for alternative treatment (0.96;
Spearman correlation).
It was noted that there was little difference in the number of treatments required to achieve
full recovery between 6 grade II patients that had at least 23 days from the onset of their
problem and other dogs in the same group that had a mean time to presentation of
approximately 9 days.
Figure 1. Aspect of the wound caused by an automobile
accident, one week after the accident.
Figure 2. Wound healing progress at session 9
same patient.
Figure 3. Inserted needles encircling the wound at session
18.
Figure 4. Outcome of the treatment after 27 sess
electrical stimulation.
Discussion
All patients in this trial were initially treated with systemic and/or topical antibacterials and
antiseptic agents, wound dressings and/or daily wound lavages, in accordance with orthodox
Western medicine. Subsequently, because insufficient or no healing results were obtained,
owners specifically sought alternative medicine to treat their pets. Due to the fact that owners
came to our premises looking for an alternative cure for their dog, it was not possible or
ethical to form an untreated control group or a group treated with standard procedures. Prior
to the trial, the fact that deterioration or no improvement of the wound was observed with
conventional procedures was taken as a diachronic control indication of the lack of
effectiveness of conventional treatments for these patients. Thus, it is accurate to regard this
unconventional treatment as a viable alternative for wound healing. However, it remains
necessary to compare the quality of healing achieved using conventional methods versus
electrical stimulation, starting both during the first visit to medical attention.
The mean time to first presentation of the dogs at our facility (11.8 + 4.49; 15.44 + 8.58;
and 24.5 + 5.21 for grades I, II and III, respectively) reflects the time in which a healing
attempt with conventional procedures and drugs had been made. Due to the unsuccessful
outcome of conventional medical treatment, dog owners sought alternative means of
treatment.
Although this procedure uses acupuncture needles, the treatment here described is not
acupuncture. However, owners regarded the treatment given to their pets as acupuncture and
considered it as highly successful. Only in three cases poor results were observed.
Acupuncture needles were chosen to deliver the electrical stimulus because they can be
smoothly inserted and removed from the healthy skin surrounding the lesion, causing minimal
pain and tissue damage. Their length allows the formation of an almost complete closed
circuit around the lesion, which was regarded in this study as necessary to enhance wound
healing. Other studies have also used stainless steel electrodes and similar semi-invasive
procedures [18,19]. With the needles, internal fluids act as natural conductors, spreading
electrical stimulus, thus avoiding the use of patch electrodes that should cover the whole
lesion area [20]. Additionally these patches are not readily available for lesions of different
surface areas. Also, the use of sterile needles spare the use of sterile conducting gel or
special dressings which otherwise would be needed to spread evenly the electrical stimulus
[21]. On the other hand, implanted electrodes produced severe tissue reactions and infections
which are of course detrimental to the wound healing process [22].
There have been several trials in which different methods of applying electricity have been
successful. Reich and Tarjan [15] reviewed the use of electrical stimulation for wound healing
and noted the emergence of improved dose criteria. Currents between 20 and 100 ?A are
currently being used and reported to increase in-growth and alignment of collagen sponges.
Electrical stimulation with negative polarity has been shown to improve collagen deposition in
excisional wounds of diabetic and non-diabetic animals [20]. Direct current (dc) stimulation
has been found to reduce wound area more rapidly than alternating current (AC), but AC
stimulation reduces wound volume more rapidly than DC [23]. Both DC and AC stimulation
caused significant increase of collagen content around experimental incisions in rats [24] and
a similar result arose from previous experiences in our laboratory [6,16,17,18] using
alternating current with switching polarities every second. DC currents of 50 to 300 ?A have
also been reported to accelerate the rate of epithelialization suggesting that electrical fields
can influence the proliferative and/or migratory capacity of epithelial and connective tissue
cells [25], a finding that is fully in accordance with our earlier results [6].
The ideal result of wound healing is rapid regeneration, leading to perfect restoration of
form and function [26]. To date, the end result is a skin functionally and cosmetically poorer
than the original dermis [4]. However, prenatal eutherian mammals have the ability to
regenerate dermis [4]. It may be then, that the ability to achieve large-scale regeneration in
post-natal mammals may not have been lost, but merely masked [4]. As in our earlier reports
[6,16, 17,18], Scardino et al. [27] informed that surgically created wounds in dogs treated with
pulsed electromagnetic field of 0.5 to 18 Hz resulted in significantly enhanced epithelialization
with skin resembling unharmed, unmodified skin. Considering that it has been cited before
that healing of a cutaneous wound is accompanied by endogenous electrical phenomena
[28], it is tempting to speculate whether electricity may be capable of disentangling at least
part of the key to regeneration [21]. Nevertheless, no definitive explanation has been
proposed for the mechanism of action by which electrical stimulus can promote skin wound
healing [6,29]. During the treatment with electrical stimuli all wounds reacted with a clear
increase in redness due to augmented blood supply (a sign previously observed in
experimental animals [16, 17]. A similar reaction has been observed in human patients with/or
at risk diabetic foot ulcers using either high-voltage pulsed current [30] or low frequency, 4 Hz
electrical stimulation [31]. It is not known how this reaction is brought about, but it is tempting
to speculate and to propose that electrical stimulation of skin lesion enhances capillary
growth, hence increasing overall blood supply to the injured area, a feature regarded as a
milestone for successful wound repair [1-3]. These results are consistent with other positive
findings using electrical stimulation to promote healing of wounds [27] or burn injuries [6,18],
as well as regeneration of tendons [32]. However, some authors have not had positive
results, perhaps because they applied a charge density out of the range suspected to be of
therapeutic value (0.1-0.9 Coulombs/cm2) or the form of electricity was not the appropriate
one [33]. Although positive results were obtained in this clinical trial, the dose and form of
electricity and/or electromagnetic stimulus to be delivered requires better definition.
It has been reported that other electro-physical modalities such as ultrasound and photo
therapy, reduce the duration of the inflammatory phase of repair and enhance the release of
factors which stimulate the proliferative phase of repair from macrophages and other cells [4].
There is also evidence that both ultrasound and certain light wavelengths can modify plasma
membrane permeability to ions such as calcium, and that this may act as a stimulus to cell
activity. Thus, repeated stimulation of these cells accounts for the observed acceleration of
the resolution of inflammation and progress through the subsequent phases of repair [4].
In veterinary medicine it is very common to encounter severe wounds or small wounds that
complicate and turn into a true challenge. This clinical trial may impact the manner in which
some of these problems are approached. One of the many factors that worsen the condition
of wounds in animals is the fact that owners cannot control the licking and soiling of the
wounds by their pets. This kind of treatment is more time consuming and demands more
attention from the owner than the customary use of dressings but, as constant visits to the
veterinary clinic are required, closer observation and proper cleaning are frequent. On the
other hand, the evident improvement of wounds motivated the owners to accomplish full
schemes and comply with proper care advised.
References
1. Madden, J. W., Arem, A. J.: Wound healing: biological and clinical features. In Sabiston,
D.C., ed.: Textbook of Surgery, W.B. Saunders, Philadelphia, pp. 265, 1981.
2. Peacock, E. E.: Control of wound healing and scar formation in surgical patients. Arch.
Surg. 116: 1325-1327, 1981.
3. Peacock, E. E.: Healing and control of healing. World J. Surg. 4: 269-270, 1980.
4. Hosgood, G.: Advances in wound healing. Compendium of Continuing Education for the
Practicing Veterinarian. 17: 155, 165, 1995.
5. Lloyd, D. H.: Healing the skin. Vet. Dermatol. 8: 225, 1997.
6. Abolafia, A. J., Sumano, L. H., Navarro, F. R.and Ocampo, C.L.: Evaluaci—n del efecto
cicatrizante de la acupuntura. Veterinaria MŽxico. 16: 27-31, 1985 (In Spanish).
7. Sumano, H. L., Ocampo, C. L., Gaytan, C. G. et al.: Eficacia cicatrizante de varios
medicamentos de patente, la z‡bila y el prop—leo. Veterinaria MŽxico. 18: 33-37, 1987 (In
Spanish).
8. Sumano, L. H., Aur—, A. A. and Ocampo, C. L.: Evaluaci—n de la mezcla prop—leo-z‡bila
(Aloe vera) como cicatrizante. Veterinaria MŽxico. 20: 407-413, 1989 (In Spanish).
9. Matera, J. M., Dagli, M .L. Z. and Pereira, D. B.: The effect of soft-laser (diodes) radiation
on wound healing in cats. Brazil. J. Vet. Res. . Anim. Sci. 31: 43-48, 1994.
10. Gupta, S. K., Singh, H. and Varshny, A. C.: Maltodextron, NF powder: a new concept in
equine wound healing. J. Equine Vet. Sci. 15: 296-298, 1995.
11. Houghton, P. E. and Campbell, K. E.: Choosing an adjunctive therapy for the treatment of
chronic wounds. Ostomy Wound Management. 45: 43-52, 1999.
12. Zheng, J., Wang, S. and Guo L.: Promotion of wound healing with fibroblast growth factor
in combined burn radiation injury. Chinese J. Plastic Surg. 10: 146-149, 1994.
13. Burleson, R. and Eiseman, B.: Effect of skin dressing and topical antibiotics on healing of
partial thickness skin wounds in rats. Surg. Gynecol. Obstet. 136: 958-960, 1973.
14. Geronemus, R. G., Mertz, P. M. and Eaglstein, W. H.: Wound healing: The effect of
topical antimicrobial agents. Arch. Dermatol. 115: 1311-1314, 1979.
15. Reich, J. D. and Tarjan, P. P.: Electrical stimulation of skin. Int. J. Dermatol. 29: 395-401,
1990.
16. Casaubon, T. E. and Sumano, L. H.: Eficacia de la electroestimulaci—n. Veterinaria
MŽxico. 22: 284-289, 1991 (In Spanish).
17. Castillo, E., Sumano, L. H., Fortoul, T. I. and Zepeda, A.: The influence of pulsed
electrical stimulation on wound healing in burned rat skin. Arch. Med. Res. 26: 185-189, 1995.
18. Sumano, L. H. and Mateos, T. G.: The use of acupuncture-like electrical stimulation for
wound healing of lesions unresponsive to conventional treatment. Am. J. Acupuncture. 27: 515, 1999.
19. Zorlu, U., Tercan, M., Ozyazgan, I., Taskan, I., Kadas, Y., Balkar, F. and Ozturk, F.:
Comparative study of the effect of ultrasound and electrostimulation on bone healing in rats.
Am. J. Phys. Med. Rehabil. 77: 427-432, 1998.
20. Thawer, H. A. and Houghton, P. E.: Effects of electrical stimulation on the histological
properties of wounds in diabetic mice. Wound Repair Regeneration. 9: 107-115, 2001.
21. Sussman, C. and Byl, N.: Electrical Stimulation for wound healing. In: Sussman, C. and
Bates-Jensen, B. M.: Wound care collaborative practice manual for physical therapists and
nurses. Aspen Publishers. 1998.
22. Steckel, R. R., Page, E. H., Geddes, L. A. and Van Vleet, J. F.: Electrical stimulation on
skin wound healing in the horse: preliminary studies. Am. J. Vet. Res. 45: 800-803, 1984.
23. Reger, S. I., Hyodo, A., Negami, S, Kambic, H. E. and Saghal, V.: Experimental wound
healing with electrical stimulation. Artificial Organs. 23: 460-462, 1999.
24. Bach, S., Bilgrav, K., Gottrup, F. and Jorgensen, T. E.: The effect of electrical current on
healing skin incision. An experimental study. Eur. J. Surg. 157: 171-174, 1991.
25. Alvarez, O. M., Mertz, P. M., Smerbeck, R. V. and Eaglstein, W. H.: The healing of
superficial skin wounds is stimulated by external electrical current. J. Invest. Dermatol. 81:
144-148, 1983.
26. Dyson, M.: Advances in wound healing physiology: the comparative perspective. Vet.
Dermatol. 8: 227-233, 1997.
27. Scardino, M. S., Swaim, S. F. and Sartin, E.A.: Evaluation of treatment with a pulsed
electromagnetic field on wound healing, clinicopathologic variables, and central nervous
system activity of dogs. Am. J. Vet. Res. 59: 1177-1181, 1998.
28. Vodovnik, L. and Karba, R.: Treatment of chronic wounds by means of electric and
electromagnetic fields. Med. Biol. Eng. Computing. 30: 257-266, 1992.
29. Gentzkow, G. D.: Electrical stimulation to heal dermal wounds. J. Dermatol. Surg. Oncol.
19: 753-758, 1993.
30. Gilcreast, D. M., Stotts, N. A., Froelicher, E. S., Baker, L. L. and Moss, K. M.: Effect of
electrical stimulation on foot skin perfusion in persons with or at risk for diabetic foot ulcers.
Wound Repair and Regeneration. 6: 434-441, 1998.
31. Cramp, A. F. L., Gilsenan, C., Lowe, A. S. and Walsh, D. M.: The effect of high and low
frequency transcutaneous electrical nerve stimulation upon cutaneous blood flow and skin
temperature in healthy subjects. Clin. Physiol. (Oxford). 20: 150-157, 2000.
32. Cleary, S. F., Liu, L. M., Graham, R. and Diegelman, R. F.: Modulation of tendon
fibroplasias by exogenous electric currents. Bioelectromagnetics. 9: 183-188, 1988.
33. Stromberg, B. V.: Effects of electrical currents on wound healing. J. Plast. Surg. 21: 121123, 1988.
TABLES
Table 1. General characteristics of study subjects
Age
No.
(years)
(%)
<1.5
Gender
Male
Female
12 (27.3)
4
8
1.5-4
15 (34.1)
9
6
5-9
7 (15.9)
5
2
10-15
8 (18.2)
5
3
>15
2 (4.5)
2
0
Total
44(100)
25
19
Table 2. Details of skin lesions and burns in study subjects (n=44)
n
Lesion Type
Underlying medical condition
10
Long standing, non-diabetic leg ulcers due to
injury
2 Chronic heart failure
and treated with topical antibacterials and
cutaneous
1 Severe obesity
1 Chronic renal failure
antiseptics
2
Chronic leg lesions caused by constant
irritation by
1 Malnourishment
leg prosthesis
4
Abdominal surgery infected with Proteus sp.
and/or
Pseudomonas sp.
with
1 Poor wound care
1 Diabetes
All unsuccesfully treated
systemic antibacterials and topical antiseptics
1
Impetigo: Widely disseminated (>5% of skin
surface)
1 Diabetes
9
Infected dog bites
3 Cases with ischaemic skin flaps
2 Deficient hygiene / Poor wound care
1 Chronic renal failure
9
Car accident resulting in a wound infected with
1 Excessive dressing;
Staphylococcus
treated with
1 Overuse of iodine-based antiseptic
sp.,
and
unsuccessfully
oral amoxicillin/clauvulanate combination
9
Second degree burns, unsuccessfully treated
with
1 Poor wound care with excessive
bandages
topical antibacterial and antiseptic drugs
Table 3. Skin lesion criteria for assignment of severity grade
Criteria
Lesion Features
Grade*
Surface area
Small (< 5 cm2)
1
Medium (5 - 10 cm2)
2
Large (>10 cm2)
3
Superficial
1
Medium
2
Deep
3
Associated systemically relevant
Mild
1
disease or condition
Medium
2
Severe
3
None or initial
1
Mild
2
Severe
3
Depth of the lesion
Infection
*grade I = 4-5 points; grade II = 6-9 points; grade III = 10-12 points
Table 4. Clinical outcome of patients treated with acupuncture-like electrical stimulation.
Lesion
grade
No. of
patients
No. of days
to
presentation
X±SD
No. of
treatments
X±SD
Burns/
wounds
Dogs
receiving
supportive
treatment
Clinical Outcome *
Poor
Fair
Excellent
I
10
11.8±4.49
8.40±2.30
4/6
1
0
0
10
II
18
15.44±8.58
10.60±4.08
3/15
3
3
1
14
III
16
24.5±5.21
41.38±6.58
2/14
4
0
3
13