Effectiveness of Lower-Extremity Electrical Stimulation to Improve Skin Perfusion

Background: While numerous studies suggest the benefit of electrical stimulation (E-Stim) therapy to accelerate wound healing, the underlying mechanism of action is still debated. In this pilot study, we examined the potential effectiveness of lower extremity E-Stim therapy to improve tissue perfusion in patients with diabetic foot ulcers (DFUs). Methods: Thirty-eight patients with DFUs were recruited. Participants underwent 60-minutes of active E-Stim therapy provided on acupuncture points above the level of the ankle joint using a bio-electric stimulation technology® (BEST) platform (Tennant Biomodulator® PRO). As primary outcome, changes in perfusion in response to E-Stim were assessed by measuring skin perfusion pressure (SPP) at baseline, 30-, and 60-min during therapy. In addition, retention was assessed 10-min post-therapy. As secondary outcome, tissue oxygen saturation (SatO2) was measured using a non-invasive near-infrared camera (Snapshot NIR, KENT Imaging Inc). Results: SPP increased in response to E-Stim therapy (p = 0.02) with maximum improvement observed at 60-min (11%, p = 0.007) compared to baseline. SPP reduced at 10-min post therapy, but remained higher than baseline (9%, p = 0.1). Magnitude of improvement at 60-min was negatively correlated with baseline SPP values (r = -0.45, p = 0.01) suggesting those with lower perfusion could benefit more from E-Stim therapy. Similar trends were observed for SatO2 with statistically significant improvement for a sub-sample (n=16) with moderate-severe peripheral arterial disease (Ankle brachial index < 0.8 or > 1.4). Conclusions: This study provides early results on the feasibility and effectiveness of E-Stim therapy to improve skin perfusion and SatO2. The magnitude of benefit is higher among those with poorer skin perfusion. Results also suggest the effects of E-Stim could be washed out after stopping therapy and thus regular daily application may be required for the effective benefit for wound healing.