The study, done by Dr. Rachelle Buchbinder and colleagues at the Cabrini Medical Center in Malvern, used the Dornier MedTech EPOS Ultra system, which was approved by the U.S. Food and Drug Administration (FDA) at the beginning of this year, for adults whose plantar fasciitis hasn't been helped by other treatment after six months.
Plantar fasciitis is a sometimes excruciatingly painful condition that occurs when the tissue supporting the foot arch becomes inflamed and breaks, creating scar tissue. It is likeliest to afflict runners, but experts say it strikes one in 10 people even if they aren't athletes.
It is treated by anti-inflammatory medications, stretching, massage and the use of splints at night, which are effective in about 95 percent of patients. Until the new devices came along, the alternative for the other 5 percent was surgery.
The Dornier device and other machines are designed to relieve the pain by sending shock waves through the foot, a technology similar to that used to break up kidney stones. The shock waves work by increasing blood flow and easing inflammation.
A report in tomorrow's issue of the Journal of the American Medical Association says Buchbinder and her colleagues tested the shock-wave therapy in 160 patients over a 15-week period. Half got the shock waves, the other half got a placebo. After six weeks, the results were essentially identical in both groups, the researchers say, with 30.6 percent of the shock-wave patients and 33.7 percent of the fake treatment patients reporting improvement. Ditto after 12 weeks, they say: 34.8 percent improvement for shock-wave treatment, 34.9 percent for fake treatment.
Buchbinder explains the difference between her results and the studies that won FDA approval by saying her study was more rigorous. "Participants in our trial not only had to have a clinical history compatible with plantar fasciitis, but they also had to have confirmation of the condition by having changes confirmed by ultrasound," she says. "All previous trials relied solely on clinical criteria alone or required the presence of a heel spur or bone pain."
Whatever the results of the Australian study, they don't apply to us, says Dr. Argil J. Wheelock, chief executive officer of HealthTronics Surgical Services Inc., the American manufacturer of the OssaTron, the first shock wave machine to get FDA approval. The OssaTron uses a spark plug to generate the shock waves, while the Dornier system passes an electric current through a coil, and the difference is vital, Wheelock says.
"This verifies what we have said all along, that there is a significant technological difference between low-energy devices and high-energy devices," he says, noting the OssaTron is a high-energy device and the Dornier machine is not. The Dornier machine "has a very narrow focal point, and therefore tends not to give the type of tissue damage needed to benefit from the treatment."
More than 5,000 patients have been successfully treated with the 60 OssaTron machines now in practice, Wheelock says, "and there will be papers forthcoming that will verify the value of the technology."
At Dornier, marketing director Kirk Wilks describes the Australian study as "poorly constructed and poorly executed, a substandard study that the FDA here in the United States would not look at."
Among other flaws, he maintains, the study did not include the kind of chronic pain sufferers who were in the trial that won FDA approval. "They didn't even have their pain level measured," he says. "In our studies, we had a pain scale of 1 to 10 and treated only people with a score of 5 or more. They took everybody."
The biggest difference, Wilks says, is that patients in the FDA approval studies got only shock-wave therapy. The Australian study let patients use drugs or other treatment, which muddied the results, he says.
Buchbinder is skeptical. "I am not convinced from the data of the previous trials that there was a clinically important benefit of shock wave over placebo," she says. "Both trials that resulted in FDA approval demonstrated small differences between groups."
What To Do
Surgery is another option if your plantar fasciitis refuses to heal, but there are risks, whereas shock-wave therapy is a low-risk option. You can learn more about plantar fasciitis and other pains in the foot from the American Academy of Family Physicians or the University of Michigan.