How does it work?
There are two theories about how shock waves work to treat ED, according to Dr. Ramasamy. One relates to neo-angiogenesis at penile tissue; the shock waves create injury and, therefore, create new blood vessels that will help treat vasculogenic erectile dysfunction. The second theory is that shock wave therapy improves ED by recruiting stem cells, which helps with growth of new corporal and penile tissue.
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Dr. Goldstein said he thinks low-intensity shock wave therapy works by activating stem cells.
“The shock wave provides an energy to the stem cells, and the stem cells get activated and grow—growing muscle, blood vessels,” said Dr. Goldstein, whose practice is among the U.S. sites conducting a placebo-controlled trial on use of low-intensity shock wave therapy for ED with the Dornier device.
Finding that ideal protocol
Just how to use it for ED—how many shocks to deliver, how often, and for how long—remains largely unanswered. Urologists and others in the U.S. need data to make low-intensity shock wave therapy clinically useful and safe, Dr. Goldstein said.
Without clear protocols, the danger exists that the therapy might not be as effective or effective at all, according to Dr. Burnett.
“You still want to be credible. You want to offer therapy that patients feel good about spending their resources and money to obtain,” Dr. Burnett said.
At the moment, there is no single gold-standard protocol.
In a recently published meta-analysis looking at low-intensity extracorporeal shock wave therapy for ED, Chinese researchers analyzed nine studies, including 637 patients, from 2005 to 2017. They found that low-energy extracorporeal shock wave therapy could significantly improve patients’ International Index of Erectile Function and Erection Hardness Score, and therapeutic efficacy could last at least 3 months (Urology Sept. 26, 2017 [Epub ahead of print]). They also reported that lower energy density, at an average 0.09 mj/mm2; 3,000 pulses per treatment; and total treatment courses of less than 6 weeks resulted in better therapeutic efficacy.
The number of treatments needed varies, according to Dr. Sloane, who said the basic GAINSWave protocol is six or 12 treatments, depending on ED severity.
“If a man needs six treatments, we’ll do two a week for 3 weeks. And the treatments are about 15 minutes each,” Dr. Sloane said.
Dr. Ramasamy, who has been part of a clinical trial using shock wave therapy with DirexGroup’s FDA-cleared MoreNova device, said men in the study are receiving a total of 1,800 shocks.
“It’s a randomized trial with two arms. It’s either every other day, for a total of six sessions, or every day, for a total of five sessions. The total number of shocks delivered is basically the same in both arms, and treatments last about 10 minutes each. Then, we follow patients at 1 month, 3 months, and 6 months,” he said.
In preliminary data, Dr. Ramasamy said men who receive the everyday treatment appear to respond better than those receiving the every-other-day treatment.
“Men would be able to have sex as early as the following week [after treatment],” he said.
Dr. Ramasamy and colleagues have recruited 44 patients so far and will recruit a total of 80.
Dr. Goldstein said his study’s protocol is to administer low-intensity shock wave therapy once a week for 6 weeks. He tells patients they can have sex the same day or night as treatment.
“The shock wave treatment is about 30 minutes and completely pain free,” Dr. Goldstein said.
As for the need for maintenance treatments, that’s not clear, according to Dr. Ramasamy.
“No one truly understands how long the effect of these shock waves lasts and what the long-term effect is. Right now, we have very good data at 3 months and very few patients at 6 months,” Dr. Ramasamy said.
Shock wave therapy appears to be safe.
“Patients tolerate it very well,” Dr. Ramasamy said. “There’s minimal pain. Sometimes, subjects have redness on the skin. But at the doses that we’re using there is very minimal change that happens to the penis, itself.”