Effect of electrical stimulation on survival of skin flaps in pigs

Flap Preconditioning by Electrical Stimulation as an Alternative to Surgical Delay: Experimental Study

Partial flap failures are unpredictable complications of reconstructive surgery. Electrical stimulation increases blood flow, capillary density, angiogenesis and vascular endothelial growth factor, anti-inflammatory effects while decreasing oxygen tension in tissues. In this study, we investigated these effective properties of electrical stimulation preoperatively on flap surgery instead of the surgical delay procedure.Modified McFarlane flaps were raised on the backs of 50 Sprague-Dawley rats. In the control group, a skin flap was made and flap survival rate was assessed on the seventh day. In the surgical delay group, 14 days after creating the bipedicled flap, the flap was totally elevated and flap survival rate was assessed on the 21st day. In the preconditioning by electrical stimulation group, the flap was created after application of electrical stimulation for 7 days. Flap survival rate was assessed on the 14th day. In the electrically stimulated ischemic flap group, the flap was created and afterward, electrical stimulation was applied for 7 days. After that, flap survival rate was assessed on the seventh day. In the surgical delay plus electrical stimulation group, following the elevation and suturing of the bipedicled flap back into its bed, electrical stimulation was applied in the first 7 days of delay, the flap was created on the 14th day, and then flap survival rate was assessed on the 21st day. In all groups, blood flow was evaluated at particular times. After completing these procedures, the flap vascularities of 5 animals from each group were assessed with microangiography.The flap survival rate of the preconditioning by electrical stimulation group was significantly higher than those of the other groups (P < 0.05). According to the blood flow estimates, except the preconditioning by electrical stimulation group and surgical delay plus electrical stimulation group, blood flow decreased in all the other groups after the postprocedure. In the microangiographic assessment of the preconditioning by electrical stimulation group, there were thin but numerous networks like vascular structures.Electrical stimulation applied to the normal area before flap elevation increased the flap survival. This increase is paramount to surgical delay which is, so far, widely known as the most effective method of improving flap vascularity.

Electrical Stimulation of Wound Healing: A Review of Animal Experimental Evidence

Significance: Electrical stimulation (ES) is a therapeutic intervention that may help specialists facilitate wound healing rates. The purpose of this section is to compile the available animal research regarding the effectiveness of ES on the injury potential, healing rate, cellular and molecular proliferation, mechanical properties, and survival rate of skin flaps. Recent Advances: Regardless of the type of ES current and polarity used, most of the animal experimental evidence suggests that application of ES can facilitate wound healing. However, treatment time should be sufficiently long to attain good mechanical strength of regenerated tissue, because tensile strength is not consistent with augmented collagen deposition. ES improves the survival rate and skin blood flow of animal flaps, but clinical studies are needed to substantiate the findings from these animal experiments. Critical Issues: Impaired or delayed healing is a major clinical problem that can lead to wound chronicity. ES with various strategies has been used to facilitate the healing process, but many aspects remain controversial. Despite much research, no consensus exists regarding the detailed effects of ES on wound healing. Nevertheless, ES has been approved by the Center for Medicare and Medicine Services for reimbursement of the treatment of some chronic ulcers. Future Directions: Exogenous ES may promote the directional migration of cells and signaling molecules via electrotaxis; however, its underlying mechanism is still poorly understood. Future studies that further elucidate the mechanisms regulating electrotaxis will be necessary to optimize the use of ES in different wound states.

The effect of TENS on random pattern flap survival in nicotinized rats

The adverse effects of cigarettes, due to their nicotine content, may cause important ischemic complications in flaps. Electrical stimulation increases blood flow in ischemic tissues, the level of vascular endothelial growth factor, capillary density, and angiogenesis while decreasing oxygen tension in tissues. Electrical stimulation is also known to increase survival rate in flaps. In this study, which tests the hypothesis that TENS (a type of electrical stimulation) contributes to enhancement of flap viability by eliminating the adverse effects of nicotine, 40 rats were divided into 4 groups of 10 rats. Nicotinization was achieved by subcutaneous administration of 2 mg/kg per day to the rats, other than those in the Control group, for 4 weeks. The rats in one of the nicotinized groups received 20 mA, 80 Hz TENS (TENS1 group) for 1 hour daily throughout the last week before McFarlane flaps of random pattern were made in the backs of all the rats. Another nicotinized group was subjected to TENS in a similar dose after flap elevation (TENS2 group). Flap blood flow was measured before and 48 hours after their construction, and their fluorescein perfusion was measured immediately after the flap elevation. The comparison of the survival rates of the flaps revealed that, although the blood flow in the Nicotine group was significantly lower than in the Control group, it was significantly higher in the TENS1 group than in both the Control and Nicotine groups. The proportion of the area stained with fluorescein, immediately after the elevation of flaps, was significantly reduced in the Nicotine group compared to the Control group. In the TENS1 group, however, it was greater than in the nicotine and TENS2 groups. Flap viability rates decreased significantly in the Nicotine group compared with the Control group. In the TENS2 group, however, an increase was observed compared with the Nicotine group.These findings suggest that although TENS performed before flap elevation does not contribute to flap survival, despite causing a rise in blood flow, it enhances flap survival when applied postoperatively. Given the practicality and low cost of TENS, it can be concluded that it may be possible to use it in the management of ischemic complications in flap operations in smokers.

Laser 830nm na viabilidade do retalho cutâneo de ratos submetidos à nicotina

OBJETIVO: Investigar os possíveis efeitos da laserterapia com laser diodo 830nm ao se contrapor a ação da nicotina na viabilidade do retalho cutâneo em ratos. MÉTODOS: Foram utilizados 16 ratos Wistar, distribuídos em 2 grupos de 8: Grupo 1- submetido à técnica cirúrgica, para obtenção dos retalhos cutâneos randômicos de base cranial, com injeção subcutânea de nicotina em uma dose de 2mg/Kg/dia, uma semana antes e uma semana após o procedimento cirúrgico e simulação da radiação laser; Grupo 2- similar ao grupo 1, cujos retalhos cutâneos randômicos de base cranial foram submetidos à irradiação do laser imediatamente após a cirurgia e nos 4 dias subsequentes. Após a eutanásia, as áreas de necrose e de tecido viável foram examinadas através do método de pesagem do Gabarito de Papel e pelo método semi-automático de análise de imagens (Mini-Mop®). RESULTADOS: Os resultados foram analisados estatisticamente através do teste ANOVA. Os valores de porcentagem de área de necrose através do método de análise mostraram uma diminuição da área de necrose no grupo 2 onde foi aplicado laser. CONCLUSÃO: O laser 830nm foi eficaz na melhora da viabilidade do retalho cutâneo em ratos submetido à ação da nicotina. Nível de evidência II: Estudos terapêuticos - Investigação dos resultados do tratamento.

Photosensitive materials and potential of photocurrent mediated tissue regeneration

Photocurrent therapy with participation of light and electrical stimulations could be an innovative and promising approach in regenerative medicine, especially for skin and nerve regeneration. Photocurrent is generated when light irradiates on a photosensitive device, and with more and more types of photosensitive materials being synthesized, photocurrent could be applied for enhanced regeneration of tissue. Photosensitive scaffolds such as composite poly (3-hexylthiophene)/polycaprolactone (P3HT/PCL) nanofibers are fabricated by electrospinning process in our lab for skin regeneration in presence of applied photocurrent. This review article discuss on the various in vitro, in vivo and clinical studies that utilized the principle of 'electrotherapy' and 'phototherapy' for regenerative medicine and evaluates the potential application of photocurrent in regenerative medicine. We conclude that photocurrent therapy will play an important role in regenerative medicine.

Iontophoretic delivery of nitric oxide donor improves local skin flap viability

The dimensions of local flaps are often limited by the vascular supply to the distal aspect of the flap. Distal flap necrosis occurs if the vascular supply is inadequate. The purpose of this study was to investigate the use of iontophoretic delivery of nitric oxide (NO) donors to a local skin flap model to improve the survival area of the flap. Thirty-two male Sprague-Dawley rats (300 g) were divided into seven experimental groups to determine the effect of iontophoretic delivery of NO on surface perfusion and flap survival area. A caudally based 3 x 11 cm dorsal skin flap was used to measure the effect of iontophoretic delivery of NO donors to a local skin flap to improve survival area of the flap. Iontophoretic delivery of the NO donors sodium nitroprusside (SNP) and diethylenetriamine NONOate (DETA-NO) resulted in a significant increase in survival area and surface perfusion when compared with sham controls. Iontophoretic delivery of saline was associated with a 13% improvement in flap survival when compared with nontreated controls. Iontophoretic delivery and subcutaneous injection of NO donors (SNP and DETA-NO) increased skin flap viability by demonstrating improved flap survival areas. The results of this study suggest that NO may serve as a postoperative treatment of skin flaps to encourage skin flap survival and prevent distal necrosis.

Effect of low-level laser therapy with output power of 30 mW and 60 mW in the viability of a random skin flap

OBJECTIVE

To assess the effects of low-level laser therapy (LLLT) with output power of 30 and 60 mW in the viability of a random skin flap in rats.

BACKGROUND DATA

Output power values in LLLT are not well defined.

MATERIALS AND METHODS

Controlled, single-blind experimental study. Thirty-six animals were randomly distributed into three groups: sham group (SG), 30-mW output power (30G), and 60-mW output power (60G). In both treated groups, a fluency of 3 J/cm(2) was used. Two minutes after elevation of a random-pattern cranially based dorsal flap (4 x 10 cm), laser irradiation was applied and repeated on the first, second, third, and fourth postoperative days. Percentages of flap necrosis were calculated on the seventh postoperative day. Also, four fragments of each flap were collected to allow determination of the percentages of vascular density according to the bidimensional method of the morphometric analysis of blood vessels. Statistical analysis included the Wilcoxon test and Kruskal-Wallis variance analysis. A significance level of 5% was elected (p < 0.05).

RESULTS

Laser-treated animals presented significantly less necrosis than the sham group (SG, 53%; 30G, 24%; p < 0.05) (60G, 25%; p < 0.05). Also, laser-treated animals presented significantly more vascular density than the sham group (SG, 37%; 30G, 57%; p < 0.05) (60G, 59%; p < 0.05).

CONCLUSION

LLLT (660 nm) with 30-mW and 60-mW output power was efficient in the increase of skin flap viability, but there was no difference between them.

A biochemical approach to wound healing through the use of modalities

Wound healing is a complex pathway that is energy dependent. Nonhealing wounds frequently require the use of physical modalities to achieve healing. There is much debate over which treatment modality to use, with varying clinical results in the literature. This review paper describes a common biochemical pathway that helps the clinician understand, at a molecular level, how the transference of energy to a wound can result in positive clinical results. The mechanisms of action for ultraviolet light, electrical stimulation, and ultrasound are reviewed along with a proposed biochemical roadmap. An emphasis on protein biochemistry is supported with an extensive review of the literature.

Effect of high frequency transcutaneous electrical nerve stimulation on viability of random skin flap in rats

PURPOSE

To determine the effect of high frequency Transcutaneous Electrical Nerve Stimulation (TENS) on viability of random skin flap in rats.

METHODS

The sample of this study was 75 Wistar rats. The skin flap measured 10 x 4 cm and a plastic barrier was interposed between the flap and donor site. After the operative procedure, animals of all groups were maintained anesthetized one more hour with electrodes positioned in the base of the flap and submitted to treatment according of their respective group. This procedure was repeated on the two subsequent days. G1: sham stimulation (control), G2: TENS (f = 80 Hz and I = 5 mA), G3: TENS (f = 80 Hz and I = 10 mA), G4: TENS (f = 80 Hz and I = 15 mA), G5: TENS (f = 80 Hz and I = 20 mA).

RESULTS

The average percentage of necrotic area was 43,11, 34,65, 49,44, 23,52, 45,10 in groups 1, 2, 3, 4 and 5 respectively.

CONCLUSION

The amplitude of 15 mA presented a lower necrotic area than control group and Transcutaneous Electrical Nerve Stimulation was efficient in increasing the random skin flap viability.

Electrical stimulation for wound healing: a review of evidence from in vitro studies, animal experiments, and clinical trials

This article reviews theories linked to endogenous bioelectric currents and the role they may play in wound repair with further appraisal of in vitro and in vivo research related to the effects of clinically applicable electrical currents on protein synthesis, cell migration, and antibacterial outcomes. In addition, studies on the effects of electrical stimulation (ES) on skin grafts, donor sites, and musculocutaneous flaps in animals are evaluated, as well as assessments of numerous clinical reports that examined the effects of ES on angiogenesis, perfusion, PtcO2, and epithelialization. Finally, a plethora of clinical trials related to the responses of chronic lower extremity wounds to ES therapy are reviewed, with emphasis on wounds caused by venous insufficiency, diabetic neuropathy, and ischemia in patients with and without diabetes mellitus. A glossary that addresses ES terminology is also included.

Experimental model for transcutaneous electrical nerve stimulation on ischemic random skin flap in rats

The objective of this paper was to develop an experimental model to be used in the study of Transcutaneous Electrical Nerve Stimulation (TENS) on viability of random skin flap in rats. The sample was 15 Wistar-EPM rats. The random skin flap measured 10x4 cm and a plastic barrier was placed between the flap and the donnor site. The animals were submited to TENS for 1 hour immediately after the surgery and on the two subsequent days. On the seventh postoperative day, the percentage of necrotic area was measured and calculated. The experimental model proved to be reliable to be used in the study of effects of Transcutaneous Electrical Nerve Stimulation in random skin flap in rats.

The effect of transcutaneous electrical nerve stimulation on the viability of random skin flaps in rats

The aim of this study was to determine the role of transcutaneous electrical nerve stimulation (TENS) in the viability of random skin flaps. In 30 Wistar-EPM rats, a random 10×4 cm skin flap was raised and a plastic barrier was interposed between the flap and its bed. Immediately after surgery and for two subsequent days, the rats in group 1 (the control group) were anesthetized for 1 h with the electrodes positioned in the base of the flap and without the administration of the electric stimulus. The rats in group 2 (the treatment group) were submitted to TENS for 1 h immediately after the surgery and for two subsequent days.

The percentage of necrotic area (averages of 43.11% in the rats in group 1 and 23.52% in the rats in group 2) was calculated on the seventh postoperative day in both groups.

Statistical analysis proved that TENS was more efficient in increasing random skin flap viability than was the method used in the control group.

The use of manual edema mobilization for the reduction of persistent edema in the upper limb

Management of persistent edema with the common treatment methods reported in the literature is not always successful. Manual edema mobilization (MEM) is a relatively new treatment regimen derived from established European and Australian lymphedema reduction regimens. It includes the use of exercises, light skin-tractioning massage techniques following the lymphatic pathways, and the use of low-compression garments. The typical patient who may benefit from the use of MEM has a presumed healthy lymphatic system, is an active participant, and performs some of the techniques independently between therapy sessions. This case report describes the use of MEM on a patient with multiple trauma, which resulted in a significant reduction--78%--of the persistent edema in the affected upper limb. A theoretic rationale is offered for each MEM technique.

Protective effect of low frequency low energy pulsing electromagnetic fields on acute experimental myocardial infarcts in rats

This series of experiments assesses the effect of exposure to low-frequency pulsing electromagnetic fields (PEMFs) in 340 rats with acute experimental myocardial infarcts. The left anterior descending artery was ligated with suture thread, and the rats underwent total body exposure to PEMFs until they were killed. Twenty-four hours after surgery, the necrotic area was evaluated by staining with triphenyltetrazolium chloride. A significant reduction of the necrotic area was observed in the animals exposed to PEMFs compared with the nonexposed controls. Exposure for up to 6 days does not appear to affect the area of necrosis, although in exposed animals an increase of vascular invasion of the necrotic area is observed: 24.3 % as against 11.3 % in controls. No effect on the necrotic area size from exposure was found when the left anterior descending artery was occluded for 60 min, followed by reperfusion. The results reported show that exposure to PEMFs is able to limit the area of necrosis after an acute ischemic injury caused by permanent ligation of the left anterior descending artery. These data are in agreement with the protective effect of PEMFs observed on acute ischemia in skin free flaps in rats and in cerebral infarcts in rabbits.

Venous ulcers: improved healing by iontophoretic administration of calcitonin gene-related peptide and vasoactive intestinal polypeptide

A study on the effects of iontophoretic administration of calcitonin gene-related peptide and vasoactive intestinal polypeptide on the healing of venous stasis ulcers of the extremities was carried out on 66 patients. Two randomized groups of patients were compared, one receiving standard treatment plus iontophoresis of calcitonin gene-related peptide and vasoactive intestinal polypeptide, and the other receiving standard treatment plus placebo iontophoresis. Calcitonin gene-related peptide and vasoactive intestinal polypeptide were administered locally by iontophoresis for 20 min three times weekly for 12 weeks. To determine the effects of the two treatments, the percentage surface area of ulcer healed and the number of healed ulcers were compared after 2, 4, 6, 8, and 12 weeks of treatment. The results demonstrate that there were significant improvements of the healing process in the group treated with calcitonin gene-related peptide and vasoactive intestinal polypeptide when compared with placebo iontophoresis, and support the use of iontophoresis administration of calcitonin gene-related peptide and vasoactive intestinal polypeptide in the treatment of venous ulcers.

Electrical stimulation in wound healing

The authors present a review of the current literature regarding electrical stimulation with special focus on the merits of its uses in wound healing. Literature from a basic science, animal studies and clinical investigations are reviewed. The literature seems to suggest that electrical stimulation can effect wound healing, but the method of delivery remains uncertain.

A comparative study of the effect of ultrasound and electrostimulation on wound healing in rats

A comparative study has been carried out to investigate the effects of electrical stimulation and ultrasound on wound healing. Eighty-four female rats were divided into four groups depending on the treatment received. The first group was given electrical stimulation of 300 microA direct current, 30 minutes daily, starting with negative polarity and then changed after 3 days of treatment. Group 2 received sham electrostimulation treatment. The third group received 0.1 W/cm2 pulsed ultrasound using the moving applicator technique for 5 minutes a day. Group 4 received sham ultrasound treatment. A total of 7 days of treatment was given to all groups. Histopathologic and biochemical analyses on the fourth and seventh days and wound breaking strength on the twenty-fifth day were performed for all groups. By accelerating the inflammatory phase, electrical stimulation had progressed the proliferative phase of wound healing earlier than ultrasound had done. Both electrical stimulation and ultrasound have positive effects on proliferative phases, but electrical stimulation was superior to ultrasound at the maturation phase. There was no difference between the two experimental groups on the mast cell reduction effect. Although ultrasound treatment may seem to be efficient in terms of time, when the effects of electrical stimulation and ultrasound on wound healing with the methods employed in our study are considered, it is concluded that electrical stimulation is a means of treatment superior to ultrasound in wound healing.

Electrical stimulation to heal dermal wounds

BACKGROUND

Numerous human and animal efficacy studies have demonstrated that electrical stimulation of the correct charge, density and total energy causes dramatically improved healing of dermal wounds. The investigations of biological actions (in vitro, animal, and human) demonstrate several effects that go a long way to explaining why electrical stimulation works.

OBJECTIVE

To discuss recent research and advances in electrical stimulation of wound healing.

RESULTS

Based on the latest scientific understanding of the wound healing process, one would expect a beneficial outcome from a therapy what decreases edema, debrides necrotic tissue, attracts neutrophils and macrophages, stimulates receptor sites for growth factors, stimulates growth of fibroblasts and granulation tissue, increases blood flow, stimulates neurite growth, induces epidermal cell migration, prevents post-ischemic oxygen radical-mediated damage, inhibits bacteria, and reduces numbers of mast cells.

CONCLUSION

Taken together, the efficacy studies and the "mechanism of action" studies provide compelling, scientific evidence that electrical stimulation is safe and effective for promoting the healing of dermal wounds.