Therapeutic ultrasound and wound closure: Lack of healing effect on x-ray irradiated wounds in murine skin

Objective: To evaluate the efficacy of ultrasonography as a therapeutic age nt in wound healing. Design: Randomized, controlled trial. Setting: University animal laboratory. Animals: Male BALB/c mice randomly allocated to 5 groups. Interventions: In group 1, mice were left untreated; in groups 2 through 5, a well-defined area on the dorsum was exposed to 20Gy x-ray irradiation. S eventy-two hours postirradiation, all mice were anesthetized by inhalation (isoflurane anesthetic) and a 7 X 7mm area wound made on the dorsum. All wo unds were videotaped alongside a marker scale 3 times weekly until closure was complete. Mice in groups 4 and 5 were treated with pulsed therapeutic u ltrasound for 5 minutes, 3 times weekly at I and 3MHz, respectively (intens ity, 0.5W/cm(2)); mice in group 3 received placebo ultrasound. Subsequently , the area of each wound was measured from video by using an image analysis system. Main Outcome Measure: Wound closure as a fraction of day zero. Results: Irradiation caused a significant (p < .01) delay in the rate of wo und closure by day 11. However, neither placebo ultrasound nor treatment at I or 3MHz affected the closure rate. Conclusion: These findings provide little evidence that I or 3MHz ultrasoun d applied to a radiation-impaired wound stimulates wound closure in mice. ( C) 2001 by the American Congress of Rehabilitation Medicine and the America n Academy of Physical Medicine and Rehabilitation.