A device developed by researchers in Drexel’s School of Biomedical Engineering, Science and Health, Philadelphia, PA, USA could help speed the process of healing chronic wounds by using ultrasound as a healing tool. By reducing the energy level on therapeutic ultrasound the team is finding a solution that could accelerate the body’s natural healing process. Caused by venous hypertension, venous ulcers can present in the form of varicose veins, swelling, discoloration, and — in the most severe form — painful ulcers of the lower extremities. Preliminary tests show that low-frequency therapeutic ultrasound can increase the rate of healing in these wounds that would otherwise heal very slowly or
not at all.
“We have been working with the idea of designing a fully wearable, lightweight and battery-powered ultrasound device for a while, but now we are concentrating on showing why it is effective and how it can be a viable treatment that can be made available to more people with these ailments,” said Dr Peter A. Lewin, professor in Drexel’s School of Biomedical Engineering, Science and Health Systems, and the primary investigator of the project. The reduction in power used in the device compared to standard diagnostic ultrasonography is significant because it allows the ultrasound to be applied directly to the dressed wound for a longer period of time. It doesn’t heat up and the pressure of the device is gentler on the injured area. The device was tested at the wound clinic at the College of Medicine, during a four-week period in which the researchers treated 20 people to determine the most effective combination of ultrasound strength and duration of time for the treatment. The most effective combination in the team’s trials turned out to be a lower frequency, 20kHz as opposed to 100kHz, for a shorter period of time, 15 minutes rather than 45. 
The test group that received this combination of treatment options saw all of its members heal completely by the end of the four-week treatment period. “The fact that this appears to be a successful active treatment for wound healing is significant because the most commonly used methods today are passive healing techniques that require more time for the wound to heal,”Lewin said. “There are very few active therapies commercially available to stimulate wound healing in these patients. There are some biosynthetic skin substitutes which may be applied to the wound and potentially deliver growth factors to stimulate healing, but these technologies are expensive and are not always covered by insurance.” “As part of a National Institutes of Health study, the group will continue to investigate how and why this treatment works. Using a near-infrared scanning device, developed at Drexel, they will be able to closely monitor the three phases of wound healing — inflammation, proliferation and remodeling — in hopes of unearthing how the mechanisms of healing are augmented by the ultrasound. “Once we’ve pinpointed the science behind this process, it can be something that could give patients an option for wound therapy that is affordable, easily applied and can be adjusted to give them the most efficient course of treatment,” Lewin said.
http://tinyurl.com/therapeutic-ultrasound