Low intensity (55 kPa) 20 kHz ultrasound heals venous ulcers

Abstract

We report the results of a second clinical pilot study (n = 19) involving treatment of chronic wounds (venous ulcers) using novel, fully wearable ultrasound array applicator operating at 20 kHz and generating pressure amplitudes close to 55 kPa (about 100 mW/cm2, Sptp). The applicator was designed as compact, tether-free, device that can be comfortably worn by subjects at home, permitting active (combined with traditional compression) therapy away from the clinical setting. Patients with venous ulcers documented for over 8 weeks were enrolled from the Drexel Wound Healing Center and, following consent, were randomly assigned into treatment or control groups. Patients were treated weekly (15 min) for a maximum of 12 visits or until wound closure. Treatments were in addition to standard of care compression therapy as ordered by the physician. Of the patients receiving at least three treatments (n = 16), the ultrasound treated group had statistically improved (p < 0.04) rate of wound closure (reduction of 8.2%/wk) compared to the rate of wound closure for the control group (increase of 7.5%/wk on average). This study represents further proof of the potential healing power of low intensity, low frequency ultrasound. Optical measurements and in-vitro work continue to support these findings as well.