Low-Intensity Shockwave Therapy for Erectile Dysfunction: A Randomized Clinical Trial Comparing 2 Treatment Protocols and the Impact of Repeating Treatment
Dimitrios Kalyvianakis, MD, PhD; Evangelos Memmos, MD; Ioannis Mykoniatis, MD, MS; Paraskevi Kapoteli, MSc; Dimitrios Memmos, MD; Dimitrios Hatzichristou, MD, PhD
FIRST PUBLISHED: February 3, 2018 – The Journal of Sexual Medicine
DOI: https://doi.org/10.1016/j.jsxm.2018.01.003
Introduction
Low-intensity shockwave therapy (LiST) has been suggested as a treatment for erectile dysfunction (ED). However, it is not known whether adding sessions affects efficacy or whether repeating treatment after a break is meaningful if a patient requests it.
This study explored these questions in two phases, comparing 6- and 12-session regimens and analyzing the value of a second round of therapy.
Study Protocol
Forty-three men with ED were randomly assigned to one of two study groups:
Group A: 21 men, average age 58
Group B: 22 men, average age 56
After screening, all patients went through a 4-week washout period, during which they did not take any phosphodiesterase type 5 (PDE5) inhibitors or use any other substances or products to improve erections.
Phase 1
During Phase 1 of the study, men in Group A received a total of 6 LiST sessions – one session each week for 6 weeks. Group B received a total of 12 sessions – 2 sessions each week for 6 weeks.
At this point, the men were followed for 6 months with no treatment. No PDE5 inhibitors or other erection-inducing medicines or products were allowed during this time.
Men who completed Phase 1 were invited to participate in Phase 2. Eighteen men in Group A and 18 men in Group B chose to do so.
Phase 2
In phase 2, all of the participants underwent 6 sessions of LiST. Group A received 2 sessions each week, while Group B received 1 session each week.
Overall, the men in Group A received a total of 12 sessions. The men in Group B received 18 sessions.
All 36 men completed Phase 2.
Each LiST session lasted approximately 20 minutes and delivered 5,000 shockwaves.
The erectile function domain of the International Index of Erectile Function (IIEF-EF) and the Sexual Encounter Profile (SEP) were used to assess progress. Question 3 of the SEP was of particular importance: “Did your erection last long enough for successful intercourse?” Results were compiled at baseline and at 1-, 3-, and 6-month follow-up points after each study phase. Penile triplex ultrasonography was performed at baseline and at the 3-month follow up.
Results
Minimally clinical important differences (MCIDs) were used as a progress benchmark. An MCID was “defined as a change in IIEF-EF score equal to or greater than 2, 5, and 7 points for mild, moderate, and severe ED, respectively.”
After Phase 1, both groups had statistically significant improvements with erections compared to baseline. Sixty-two percent of the men in Group A and 71% of those in Group B had MCIDs. Forty-seven percent of Group A and 65% of Group B answered “yes” to SEP question 3, indicating that they could maintain an erection throughout a sexual encounter.
“Yes” responses to SEP question 3 increased for both groups over Phase 2, with Group A seeing the larger increase.
| % “Yes” at Baseline | % “Yes” at 6-month follow up | |
|---|---|---|
| Group A | 47.0% | 61.9% |
| Group B | 68.1% | 68.4% |
After 6 sessions, 62% of the men achieved MCIDs from baseline. After 12 sessions, the rate was 74%, and after 18 sessions, the rate was 83%.
Statistically significant improvements in erectile function were noted with additional sessions, with an average improvement in IIEF scores of 3, 5, and 7 points compared to baseline at 6, 12, and 18 months, respectively.
Discussion
Overall, Phase 1 results suggest that:
- Six and 12 sessions were safe with no significant differences in erectile function between groups.
- Twelve sessions can be safely applied without a break between session 6 and 7.
Phase 2 results show that repeating shockwave therapy is safe, and results in additive improvements in erectile function. The greatest overall efficacy was found with 18 sessions in this study, but further research is needed to determine if this number is “treatment saturation.” Also, Phase 2 results suggest that improvements are possible after 12 sessions whether treatment is conducted in one course or two courses.
The authors acknowledged several limitations including a small sample size and lack of a sham-controlled arm. Experts caution that without a sham-controlled arm, the current study is unable to demonstrate whether LiST is superior to placebo. Experts additionally note that at the present time, LiST remains an off-label investigational therapy with contradictory findings in the literature. Further randomized, controlled studies are needed to determine appropriate treatment protocols and to identify whether it offers any true clinical benefits compared to conventional therapies.
Note: Please see the Sexual Medicine Society of North America’s Position Statement on ED Restorative (Regenerative) Therapies (including shockwave therapy) here.