LOS ANGELES – New ultrasound devices have shown promise in healing wounds, according to Dr. Jonathan Rosenblum, a podiatrist at Shaare Zedek Medical Center, Jerusalem.
"In the right hands, with the right modality, it could be a sonic boom," he punned. He cautioned that "there is no good evidence yet for ultrasound for any aspect of wound care." But in his presentation at the Diabetic Foot Global Conference, he said that many encouraging cases have been reported, along with impressive laboratory research, and that he hopes to launch randomized, controlled trials soon.
Dr. Rosenblum first became interested in the technology when he tried it out on a painful venous ulcer and found that the treatment not only reduced pain but seemed to speed the healing. "With a simple saline dressing and no compression, within 10 days we went from a nasty, sloughy wound bed to a soft epithelial covering," he said at the conference, which was presented by Valley Presbyterian Hospital.
He has since tried it out on a wide variety of wounds with good success.
Researchers have experimented with ultrasound therapy using longitudinal, shear, and acoustic waves, he said. And they’ve tried high and low frequency, and high and low intensity.
Some high-frequency ultrasound devices are being used to treat pain in soft tissue, said Dr. Rosenblum. But they aren’t effective for wound care because the energy isn’t focused on the dermis, he said. "A lot of it is being wasted deeper than you need it, and you’re not getting the effect that you want."
To address that problem several years ago, inventors experimented with low-frequency devices, but these machines were too large to be commercially viable, said Dr. Rosenblum. "They took up whole rooms," he said. "These were 6-foot-tall devices."
More recently, smaller devices have been created using surface acoustic waves, a technology that is also used in some touch screens, he said. It is this technology that looks promising for wound care, said Dr. Rosenblum.
Experiments by John Loike, Ph.D., at Columbia University in New York have shown that the migration of neutrophils and epithelial cells can be significantly influenced by this type of ultrasound waves, said Dr. Rosenblum.
Other researchers have shown increased local uptake of systemic gentamicin in pseudomonas biofilms, increasing the kill rate of the antibiotic.
In addition to fighting pathogens, ultrasound may spur skin growth, said Dr. Rosenblum. "It has been shown effective in all types of collagen synthesis, including cartilage, tendon, [and] skin," he said. And it has shown capacity to reawaken senescent cells, he added.
So how can ultrasound cause these effects?
One possibility is the heat generated by the energy from the waves, said Dr. Rosenblum, which could affect various aspects of healing. For example, collagenase is sensitive to temperature.
But heat itself is probably not the whole story, he said. One other possibility is that ultrasound may stimulate cells to produce nitrous oxide. In addition to being a powerful analgesic, ultrasound is a potent vasodilator.
"We came to the conclusion that ultrasound may be beneficial to wound healing," Dr. Rosenblum concluded. "I’d like to see a couple of good studies that could change that to ‘is beneficial to wound healing.’ "
Dr. Rosenblum disclosed that he an independent consultant to NanoVibronix and a consultant to BRH Health.