The treatment of chronic wounds, including diabetic, venous, and decubitus ulcers has an annual cost of over $25 billion in the US alone. Over 2 million patients are treated for venous ulcers annually, contributing nearly $1 billion dollars toward that cost. Treatments for venous ulcers and their effectiveness vary widely; however, none of them guarantees complete healing, resulting in a large number of chronic wounds.

To improve the effectiveness of the available treatments of venous and diabetic ulcers and other chronic wounds Drexel researchers and clinicians have developed a light-weight, wearable, low-power, low-frequency ultrasound applicator that can be used in combination with the standard of care. The device is shown in the picture on the right. The ultrasound applicator is as small as a wristwatch and contains between one and several round ultrasound actuators (4 actuators shown here) depending on the intended use and the size of the wound. The actuator is powered by a battery-operated power supply shown as a small black box worn by the presenter on the belt.

Two small clinical pilot studies have been conducted at Dr. Weingarten’s Wound Management Center, Drexel College of Medicine to determine the effectiveness of low frequency, low-intensity ultrasound on the treatment of venous ulcers.  The first pilot study (n=20) focused on finding the optimal treatment parameters.  Patients, all receiving the standard of care in addition to the ultrasound treatment, were randomly assigned to one of three treatment groups: 15 minutes at 20 kHz, 45 minutes at 20 kHz, and 15 minutes at 100 kHz, as well as the control group that received only the standard of care. The ultrasound treatment was applied once a week for four weeks. At the end of the four week period there were healed and non-healed wounds in each group except that in the 15 min/20 kHz group all 5 patients’ wounds have healed.  The second pilot study (n=19) focused on the 20 kHz for 15 minute treatment which performed best in the first pilot study.  Patients were assigned to either treatment or the control group and were treated over 12 visits (typically weekly).  The treated group had an average reduction in wound size of 8.2%/week whereas the untreated group had an increase in wound size of over 7%/week (p<0.05).  Optical measurements of blood flow as well as in-vitro work have supported the wound size findings as well.