Electrical Stimulation
The use of various forms of electrical current in augmenting tissue repair was reported as early as the 1600s when charged gold leaf was used to prevent scarring in smallpox survivors (Kloth & Feedar 1988). The therapeutic effects of electrical stimulation for wound healing have been well documented since the 1960s, especially for wounds not responding to standard forms of treatment (Kloth & Feeder 1988; Bogie et al. 2000).
Galvanotaxis is the process by which electrical stimulation directs cell movement and it is thought to be a process that can impact wound healing through the migration of cells such as epithelium, macrophages, neutrophils and fibroblasts (Feedar et al. 1991; Bogie et al. 2000). Under normal circumstances there is a flow of charged particles from an uninjured area to an injured area triggering a biological repair system. The belief is that application of exogenous electrical current should be able to enhance healing in non-healing wounds by mimicking the body’s own healing system (Carley & Wainapel 1985). A second theory purports that the application of electric current activates cutaneous nerves and creates a centrally mediated increase in circulation to the wound to indirectly promote healing (Kaada 1982). Despite the increasing use of electrical stimulation to promote wound healing, there remains a lack of clear understanding as to how it works to repair tissue (Bogie et al. 2000).
Some of the documented effects of electrical stimulation on wound healing include decreased healing time, increased collagen synthesis, increased wound tensile strength, increased rate of wound epithelialization and increased bactericidal and bacteriostatic effects (as cited in Kloth & Feedar 1988). Electrical stimulation has also been shown to indirectly improve healing by improving tissue perfusion and reducing edema formation (Houghton & Campbell 2007). The studies on electrical stimulation for wound healing have examined low-intensity direct current, high voltage pulsed direct current, and alternating current. The literature shows a high variability as to which protocols are the most effective for a specific patient or ulcer (Bogie et al. 2000).
The use of electrical stimulation to promote closure of pressure injuries, when combined with standard wound interventions, has been recommended in both the able bodied and individuals with SCI. Most studies discuss the adjunctive role of electrical stimulation in pressure injuries which have failed to respond to standard treatments (Houghton et al. 2013; Consortium of Spinal Cord Medicine 2000; Keast et al. 2006; AHCPR, Executive Summary # 15 1992).
| Author YearCountry Research DesignScore Total Sample Size |
Methods | Outcome |
| Systematic Reviews | ||
| Lala et al. 2016 Canada Review of published articles until Jan2014 AMSTAR=6 N=15 |
Method: Systematic review of literature including randomized controlled trials (RCTs) and clinical noncontrolled trials assessing electrical stimulation therapy (EST) for pressure injury (PU) treatment. Databases: CINAHL, The Cochrane Library, Dissertation & Theses, EMBASE, ProQuest – Nursing & Allied Health, PubMed, SCOPUS. Level of evidence: Level 1a (2 RCTs), Level 2 (4 RCTs, 3 PCTs), Level 3 (2 retrospective controlled studies), Level 5 (4 case series). Questions/measures/hypothesis: To determine the effectiveness of EST on the healing of PUs in individuals with spinal cord injury in comparison with control groups. |
1. A meta-analysis of three studies found that EST resulted in a significantly larger decrease in PU size compared to standard wound care or sham EST (p<0.001). 2. One retrospective control study and one RCT also found that those treated with biphasic pulsed current healed significantly faster than those treated with low-intensity direct current, sham, or conservative therapy. 3. A meta-analysis of four RCTs found that healing of a PU with EST was 1.55 more likely than with standard wound care or sham EST (p=0.01). 4. Three RCTs found that PUs receiving high-voltage pulsed current had a larger percent decrease in wound surface area compared to a sham group. 5. Only one study reported minor adverse events related to EST treatment and none reported on the potential of EST to alleviate pain or improve quality of life. |
| Liu et al. 2016 United Kingdom Review of published articles from 1985- Jul2014 AMSTAR=6 N=8 |
Method: Systematic review of literature including randomized controlled trials (RCTs) and nonrandomized clinical controlled trials (CCTs) assessing electrical stimulation (ES) for pressure injuries (PUs) in spinal cord injury (SCI) patients. Databases: Medline, EMBASE, CINAHL, PsycInfo, Cochrane Central Register of Controlled Trials. Level of evidence: Jadad: Low risk of bias (2 RCTs), Moderate risk of bias (4 RCTs), High risk of bias (2 CCTs). Questions/measures/hypothesis: To assess the effect of ES as an adjunctive therapy to improve healing rates for PU in people with SCI; to explore whether different types of ES currents and electrode placement have any influence; to examine whether ES treatment worsens PU in SCI compared to no treatment. |
1. Pooled analyses of seven trials showed that ES resulted in a significantly higher weekly healing rate than sham/no ES (p=0.001). 2. Pooled analysis of six trials showed that pulsed current ES resulted in a significantly higher weekly healing rate than those without ES treatment (p=0.0005). 3. One CCT found that pulsed current ES resulted in a significantly higher weekly healing rate compared to direct current ES (p=0.03). 4. Meta-analysis of four trials found that both placing electrodes directly on the wound (p=0.01) and placing on intact skin (p=0.01) significantly increased the weekly healing rate compared to those that did not receive ES. 5. Two trials showed that ES resulted in significantly higher numbers of completely healed ulcers (p=0.02) but non-significantly lower numbers of ulcers worsening compared to no ES. 6. Only one study reported minor adverse events related to ES. |
| Interventional Studies | ||
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Karsli et al. |
Population:Mean age=32.6 yr; Gender: males=22, females=5; HVES Group (n=15): Injury etiology: SCI=8, |
1. The WSA improved significantly after treatment in both groups for stages I, II, and III (p<0.05). |
| Effect Sizes: Forest plot of standardized mean differences (SMD ± 95%C.I.) as calculated from pre- and post-intervention data
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| Houghton et al. 2010 Canada RCT PEDro=9 N=34 |
Population: Mean age=23-74 yr; Gender: male=20, female=14; Time since injury=1-51 yr; Severity of injury: complete and incomplete; Ulcer location: IT, sacrum, coccyx, hip, leg; Duration of ulcer=0.3-20 yr. Intervention: Stimulation with monophasic high voltage pulsed current (HVPC) 19,200 min/day 7 days/wk with standard wound care (interdisciplinary team assessment) or standard wound care alone (SWC). Outcome Measures: Percent decrease in wound surface area. |
1. Percent decrease in wound surface area was significantly greater (p=0.048) in those treated with HVPC+SWC (70 ± 25%); versus those with only SWC (36 ± 61%). 2. Proportion of Stage III, IV, X pressure injuries improving by at least 50% was significantly greater in the HVPC+SWC than in the SWC (p=0.20). |
| Cukjati et al. 2001 Slovenia RCT PEDro=5 N=217 |
Population: Mean age: 28-59 yr; Injury etiology: 71.7% SCI; Time since injury: 2-38 mo; Wound area >1cm2 and at least 4 wk duration; Ulcer location: trochanter, sacrum, gluteus, other; Ulcer duration: 3-18 wk. Intervention: Biphasic-current stimulation (AC group) (N=136) received biphasic current by placing electrodes on intact skin across the wound. Direct-current stimulation (DC group) (N=35) received direct current (0.6mA) through a positive electrode placed over wound and 4 negative electrodes placed on intact skin around the wound. Stimulation was applied 0.5hrs, 1hr, or 2 hours/day 7 days/wk. Comparisons were made to the Conservative treatment group (N=54) and sham group (N=23). Outcome Measures: Wound healing rate. |
1. AC group healed significantly faster than the sham group (p=0.018) and at the same rate as the DC group (p=0.170) with the 2-hour wound treatment. 2. AC group healed significantly faster than DC group with 1-hour treatment (p=0.001). 3. Wound healing rate depend upon wound area, grade, shape, patient’s age, elapsed time from SCI to wound appearance, and elapsed time from wound appearance to beginning of treatment. |
| Adegoke & Badmos 2001 Nigeria RCT PEDro=6 N=7 |
Population: Mean age=21-60 yr; Mean ulcer surface area=15.8 mm; Ulcer location: greater trochanter and sacrum. Intervention: Stimulation with interrupted direct current (IDC) and nursing care or placebo IDC and nursing care; 3-45 minute treatments 1x/wk for 4 wk. Outcome Measures: Percent decrease in wound surface area. |
1. Surface area of pressure injuries in IDC group decreased by 22.2% versus 2.6% in placebo IDC group. 2. Most of the decrease in surface area occurred during the first two wk of the study (IDC group 15.4 to 13.3 mm2, % change 15.8%; placebo IDC group 15.4 to 15.1 mm2, % change 1.9%). |
| Karba et al. 1997 Slovenia RCT PEDro=6 N=50 |
Population: Pressure injury ≥ 500 mm2; Pressure injury stage: III or IV. Intervention: DC+ group receiving positive stimulation electrode overlaid on ulcer; DC+/- group received the same stimulation but two electrodes were placed on healthy skin across the wound; SHAM group had electrodes placed on the wound but no current. Outcome Measures: Relative rate of healing. |
1. The DC+ group reported significantly (p=0.028) greater relative healing rate (7.4%/day) compared to SHAM group (4.2%/day), while the DC+/- group (4.8%/day) had similar relative healing rates as the SHAM group. |
| Baker et al. 1996 USA RCT PEDro=4 N=80 |
Population: Mean age=17-76 yr; Gender: males=66, females=14; Time since injury: 1-420 mo; Severity of injury: complete and incomplete; Total number of wounds=192; Ulcer location: foot, thigh, ischial and sacral. Intervention: Stimulation of A (asymmetric biphasic), vs. B (symmetric biphasic) vs. microcurrent (MC) group originally thought to incorporate stimulation below effective level became the 3rd treatment group when some early therapeutic effect was noted. All remained on their stimulation protocols until their ulcers healed, the MD intervened or subject withdrew from study. Control group received sham for 4 wk then were entered into either A or B groups. Electrical stimulation treatment for all subjects consisted of 1.5 hr of stimulation 5 days/wk. Outcome Measures: Mean rate of healing. |
1. No statistical differences were noted between the initial or discharge ulcer areas or in the mean healing rates among the four treatment groups. 2. Comparing the descriptive data by classifying them as good or poor healing responses failed to identify any statistically significant differences between the 2 groups. 3. When looking at the good response group, the group A protocol was most effective as compared to the MC and C protocols (p<0.05). No significant differences were found between B protocol and other treatments. 4. Those in the control group who had wounds healed by either protocol A or B showed that the healing rate was greater (43.3% Δ/wk) than it was during the control period (9.7% Δ/wk). |
| Jerčinović et al. 1994 Slovenia RCT PEDro=5 N=73 |
Population: Mean age: 18-68 yr; Severity of injury: >1 mo; Ulcer location: sacrum, legs, trochanter, gluteal, other. Intervention: Stimulation with biphasic current (n=61) 2 hrs/day 5 days/wk for 4 wk in addition to conventional therapy was compared to the control group receiving conventional therapy alone (n=48). Outcome Measures: Mean rate of healing. |
1. The healing rate of the electrical stimulation group (5.7±7.1 %/day) was significantly higher (p=0.007) than the control group (2.7±3.6 %/day) 2. There were 58 out of 81 pressure injuries (61 electrical stimulation group and 20 cross-over group) which received electrical stimulation closed completely. |
| Griffin et al. 1991 USA RCT PEDro=7 N=17 |
Population: Mean age=10-74 yr; Gender: male=17; Time since injury=3-1820 wks; Severity of injury: complete and incomplete; Ulcer location: pelvic (sacral/coccygeal or gluteal/ischial) ulcers; Duration of ulcer=1-116 wk. Intervention: Stimulation with high voltage pulsed current (HVPC) or placebo HVPC for one hour a day for 20 consecutive days. All patients received equivalent dressing changes. Wounds were mechanically debrided as necessary. “Efforts” were made to relieve pressure, but this was not described. Outcome Measures: Percent decrease in wound surface area. |
1. Surface area of pressure injuries of HVPC group decreased by 80% versus 52% in placebo HVPC group. 2. Percentage of change decrease in the wound surface area (WSA) exhibited by the HVPC group was greater than placebo group at day 5 (p=0.03), day 15 (p=0.05) and day 20 (p=0.05). |
| Stefanovska et al. 1993 Slovenia Prospective Controlled Trial N=150 |
Population: SCI with one or more pressure injuries (otherwise, not specified). Intervention: Currents were applied across the wounds by a pair of self-adhesive skin electrodes. DC group (n=18) treated with direct currents (600µA) for two hours daily. AC group (n=82) were treated with low-frequency pulsed currents for two hours daily. CO group (n=50) received “conventional” treatment (not described) for the first mo. Outcome Measures: Mean rate of healing. |
1. The healing rate for the AC group (n=42, 5.43%/day) was significantly better than the other two groups DC (n=12, 4.62%/day, p=0.03), CO (n=34, 2.87%/day, p=0.00), after excluding those with very deep, superficial, or long-term wounds. |
| Recio et al. 2012 USA Case Series N=3 |
Population: Adults with SCI and recalcitrant pressure injuries; Ulcer location: heel, ischium, IT. Intervention: High voltage electrical stimulation (HVES) was applied directly into the wound bed for 60 minutes 3-5 times/wk until completely healed. Outcome Measures: Healing recalcitrant pressure injuries. |
1. HVES enhanced healing of Stage III-IV pressure injuries that were unresponsive to SWC. 2. Long-standing (11-14 mo) pressure injuries were completely healed after 7-22 wk of treatment with HVES. |
Discussion
Karsli et al (2017) compared the efficacy of high-voltage electrical stimulation (HVES) with ultrasound (US) in treating Stage II through Stage IV pressure injuries of hospitalized patients. Pressure injuries of patients in the HVES and US groups healed at a mean rate of 43% and 63%, respectively. There was no statistically significant intergroup difference in healing found after treatment. Therefore, study authors concluded that both HVES and US are promising methods for wound healing, and both electrotherapy modalities have been demonstrated to support the healing of pressure injuries.
Recio et al. (2012) conducted a retrospective case series examining the effects of high voltage electrical stimulation (HVES) one hour per day, 3-5 times per week on healing recalcitrant pressure injuries in subjects with SCI. HVES was shown to enhance healing of Stage III and IV pressure injuries that were unresponsive to standard wound care. Recalcitrant pressure injuries (11-14 months) were completely closed within 7-22 weeks of treatment with HVES.
Houghton et al. (2010) conducted a randomized single blind study evaluating the effects of high voltage pulsed current (HVPC) with standard wound care for healing pressure injuries in community dwelling patients with SCI. Subjects who received HVPC showed a significant decrease in percent wound surface area (WSA) after three months compared with those who received standard wound care alone (p=0.048). The proportion of Stage III, IV, and unstageable ulcers in which WSA improved ≥50% was significantly higher in the HVPC group than the standard wound care group (p=0.02).
Adegoke and Badmos (2001) randomly treated six stage IV pelvic pressure injuries with standard nursing care augmented with interrupted direct current or with placebo IDC. Subjects treated with IDC and nursing care showed a decrease in WSA by 22.2% versus 2.6% in the placebo group.
Cukjati et al. (2001) randomly divided participants into four treatment groups: biphasic current, direct current, sham treatment, and conservative treatment. Wounds treated for two hours with biphasic current healed significantly faster than sham-treated wounds (p=0.018) and conservative therapy, but healed at similar rates as direct current (p=0.170). Although wounds treated with direct current healed faster than sham treated wounds, the difference was not statistically significant. (p=0.085).
Karba et al. (1997) demonstrated that when using direct current, placement of the positive stimulation electrode covering the pressure injury and the negative electrodes on intact skin resulted in a greater relative healing rate per day (7.4%, p=0.028) compared to when the positive and negative electrodes were both placed on intact skin on opposite sides across the wound (4.8%)
Baker et al. (1996) showed that for ulcers that responded to any form of electrical simulation (“good responses”), asymmetric biphasic stimulation (group A) was most effective for enhanced wound healing. Wounds that were already showing healing in the control group, with the addition of either protocol A or B (symmetrical Biphasic) showed that healing rate was greater (43.3% Δ/week) when compared to control period (9.7% Δ/week).
Jerčinović et al.(1994) demonstrated that pressure injuries in patients with SCI treated with low frequency pulsed current and conventional therapy for four weeks had a significantly (p=0.006) higher healing rate than those treated with conventional therapy alone. Subjects in the conventional group who crossed over to the electrical stimulation group after fours had improved healing rates in 19 out of the 20 subjects.
Stefanovska et al. (1993) treated 150 pressure injuries in individuals with SCI with conventional therapy alone, or in combination with direct or alternating current. Wounds treated with low frequency pulsed current (alternating current) showed significantly better healing rates than those treated with direct current or conventional treatment alone after the exclusion of deep, superficial and long-term wounds.
Griffin et al. (1991) also performed a randomized controlled trial showing the efficacy of HVPC for healing pelvic pressure injuries in subjects with SCI. When compared to the placebo group, subjects treated with HVPC showed a greater percentage decrease in WSA at day 5 (p=0.03), day 15 (p=0.05) and day 20 (p=0.05).
While there were differences in the type and duration of electric current applied in the nine studies, and in some cases electrode placement, all of the studies demonstrated that when used in conjunction with standard wound management electrical stimulation accelerates the healing rate of pressure injuries in patients with SCI. More study is needed to determine optimum electric current and application protocols to enhance healing of pressure injuries post SCI. Mittman et al. (2011) reported that in additional to standard wound care, electrical stimulation results in a cost savings of $224 over a one-year time frame for treating stage III and IV pressure injuries in individuals with SCI. The cost-savings associated with improved healing rates offset the cost of adding electrical stimulation to standard practice.
Conclusion
There is level 1 evidence (from seven RCTs: Karsli et al. 2017; Houghton et al. 2010; Cukjati et al. 2001; Adegoke & Badmos 2001; Karba 1997; Jercinovic 1994; Griffin 1991) that electrical stimulation accelerates the healing rate of stage III and IV pressure injuries when combined with standard wound management.
