The Ache: Ultrasound energy is widely used by physical therapists and other clinicians to treat sports injuries and chronic pain. But because the machines are hand-held, treatment is generally limited to 15 minutes or less. Some scientists think longer treatments will be more effective.
The Claim: New wearable ultrasound devices can be used almost anywhere for four to six hours, sometimes more, at a time.
The Verdict: Several small studies show reduction in pain in the upper back, pelvis and rotator cuff, as well as increased mobility among people with arthritic knees. But the work remains preliminary and larger, more rigorous independent studies are needed to prove the devices’ effectiveness, says Stephen G. Rice, a sport medicine doctor in Neptune, N.J., and a fellow of the American College of Sports Medicine. Since the machines cost about $1,000, “I wouldn’t be running out to buy one,” he adds.
Ultrasound devices used for pain treatment deliver longer and higher energy pulses than the type used for imaging, scientists say. Therapeutic ultrasound penetrates tissue, resulting in a slight heating effect, they say. It may improve circulation and aid in intake of nutrients, which can help tissue recover more quickly and alleviate pain, they add.
Most ultrasound units use wands sliding across the skin to deliver the energy. But two companies, ZetrOZ Inc. of Trumbull, Conn., and Nano Vibronix Inc. of Melville, N.Y., now sell wearable devices. The new machines use small round applicators, or patches, that attach to the skin and are connected by wires to a controller.
Wearable ultrasound “can be applied by the patients to themselves and used at home or at work,” says David O. Draper, professor of sports medicine at Brigham Young University in Provo, Utah, who has studied the ZetrOZ device in research funded by the company. The devices have lower energy but are used for longer periods than hand-held ultrasound, Dr. Draper says. ZetrOZ’s Sam device, which hit the U.S. market earlier this month, delivers 18,000 joules of energy during the course of a four-hour treatment with two applicators, compared with 1,500 to 2,000 joules for a typical, brief in-office treatment, he adds.
The device costs $799 with one applicator, $199 for an additional one. Adhesive pads for the applicators are $2.50 to $2.99 each, depending on the quantity.
Nano Vibronix’s $850 PainShield device comes with four self-adhesive patches that must be replaced about every 50 hours of use for about $45 each, says KevMed LLC, the Addison, Texas, distributor of the device in the U.S. since 2012.
Both machines are available by prescription; buying one for home use is generally not covered by insurance, the companies say.
In study of 16 women with pelvic pain, regular use of the PainShield reduced self-reported pain scores over an average follow-up period of six months, according to an abstract published last year in the Journal of Minimally Invasive Gynecology. The study was co-authored by Texas researcher David Wiseman, who founded KevMed.
In a study of 30 patients with chronic upper back pain, published last year in Ultrasound in Medicine and Biology, men who wore the Sam for an hour a day had a 19% decrease in self-described pain following the treatment, compared with 8% for those using a placebo. Women experienced a 12% decrease. It’s possible women will take longer to see a benefit and will respond better to longer sessions, says Sam inventor George Lewis, who co-authored the study, which received funding from ZetrOZ.
Since the energy of these new ultrasound devices is low intensity, they can be used for hours without risk of skin burns, the companies say. It’s recommended they not be used over cancer tumors, because of a concern that the energy could speed growth, they say.