20—100 kHz, ultrasound assisted treatment of chronic wounds

Abstract

We report the results of a limited (20 patients) clinical study involving treatment of chronic wounds (venous ulcers) using novel, fully wearable ultrasound array applicator operating in the range of 20—100 kHz and generating pressure amplitudes close to 55 kPa (about 100 mW/cm2, Sptp). 20 kHz, 15 min exposure was determined to be the most effective in terms of expediting reduction in wound area (p < 0.05). 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. The system is safe for extended periods of application and the arrangement of the piezoelectric elements in the applicator has been adjusted allowing patient treatment customization, especially treatment of irregularly shaped ulcers. A set of systematic experiments in vitro aiming at the identification of potential mechanisms of the wound healing was also performed; the results verified that the exposure matrix used in clinical setting as mentioned above (20 kHz treatment for 15 min) produced the greatest increase in cellular metabolism (p < 0.05) and cell (fibroblasts) proliferation (p < 0.01) vs. a sham. The subsequent in vitro experiments will focus on collagen production, crucial to wound healing. [NIH 5R01EB009670.]