Experimental methods for ultrasonically enhanced wound healing

An initial study into the synergistic effects of combining therapeutic ultrasound insonation and collagen treatments was conducted. Experimental methods were developed to: 1) provide uniform, calibrated ultrasound exposure, including transducer design, calibration, positioning, and alignment; 2) insure ultrasound coupling into wound sites; 3) create uniform wounds of the proper size and depth; and 4) accurately characterize the mechanical properties of the healed wounds. Full thickness wounds of 1.5 cm in diameter were used in adult Yucatan mini-pigs with an experiment duration of 21 days. A custom ultrasound exposure system was used operating at 0.75 MHz and 100 mW/cm² (ISATA) output intensity. Wound areas were treated with ultrasound for 5 minutes daily. Histological evaluation indicated that: 1) collagen treatment produced more cellular organization; and 2) ultrasound treatment reduced inflammatory response. In-vitro mechanical testing showed: 1) ultrasound treatment combined with either the collagen bead suspension or a saline dressing produced stronger and tougher healing tissues; and 2) ultrasound treatment combined with a hydrocolloid dressing resulted in weaker and more fragile tissues