Retrospective Comparison of Focused Shockwave Therapy and Radial Wave Therapy for Men With Erectile Dysfunction

Shannon S. Wu; Kyle J. Ericson; Daniel A. Shoskes

Disclosures

Transl Androl Urol. 2020;9(5):2122-2128. 

In This Article

Discussion

Low-intensity SWT is emerging as a non-invasive alternative or supplemental option to PDE5 inhibitors for men with vasculogenic ED. To date, preclinical and clinical studies have utilized fSWT to deliver shockwaves. Despite the absence of clinical studies, rWT use is becoming widespread, which may be due to the ease of use of these devices and minimal FDA restrictions. rWT is widely used in other fields for indications such as venous ulcers and plantar fasciitis with high-quality evidence to support its use.[21,22] In this retrospective study, we demonstrated that rWT was clinically efficacious in treating men with a history suggestive of vasculogenic ED (mean SHIM improvement of 6.8), and clinical outcomes were not appreciably different between men treated by rWT and fSWT.

The proposed mechanism of action of SWT includes microtrauma that stimulates angiogenesis, stem cell proliferation, and nerve regeneration.[23,24] In rat models of ED, SWT lead to increased vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS) release within the corpus cavernosum.[25] Because these studies were performed using focused shockwaves, the biological effects of rWT are less well-understood. Nevertheless, if the radial wave penetrates the tissue of interest and causes non-lethal trauma to the target cells, it is reasonable to assume that the injury response would be agnostic to the energy source of the wave, especially if an equivalent clinical response is seen. Side effects of both fSWT and rWT are minimal and short-term, including bruising, swelling, paresthesia, or pain in the treatment area.[26]

Prior SWT trials have shown efficacy with fSWT generators such as Direx MoreNova,[27] Stortz Duolith SD1,[28,29] and Omnispec ED1000.[1,2,27–29] Several meta-analyses have shown focused shockwave therapies to be clinically favorable in ED.[8–11] In a meta-analysis of seven randomized sham-controlled trials, Clavijo et al. reported a SHIM improvement of 6.4 points after fSWT compared to 1.65 in those treated with sham therapy.[8] Several subsequent meta-analyses demonstrated that men treated with fSWT experienced SHIM improvements of 2.0–4.23.[9–11,26,30] Most studies included in these meta-analyses prohibited PDE5i use during fSWT treatment, highlighting the independent efficacy of fSWT therapy in patients who likely did not respond to first-line PDE5i treatment. This data suggests utility of fSWT for ED in PDE5i non-responders or for its dual use with PDE5i.

rWT has garnered increasing use and attention in non-urological fields. The orthopedic field has extensively used rWT for treatment of conditions such as biceps tendinopathy,[31] knee tendinopathy,[15] and plantar fasciitis.[15,31,32] A meta-analysis of fSWT and rWT in soft-tissue musculoskeletal injuries showed that the treatment modalities are equally safe, with varying efficacy for different injuries, although no direct head-to-head comparisons have been done.[13]

This study has several limitations. The retrospective design, relatively small sample size, and unblinded nature of treatment preclude the ability to make definitive conclusions of efficacy of either modality against sham. Although 24% (6/24) and 46% (11/24) of patients reported no improvement in the rWT and fSWT groups, respectively, the small number of patients in each arm may have precluded the detection of a statistically significant difference. The findings from this pilot study are unable to provide definitive guidelines of superiority of one technique over another. However, larger studies powered for a superiority analysis may corroborate our findings more definitively. In keeping with most ED trials, a placebo effect likely accounts for a portion of the clinical benefit observed in both study arms. However, our data align with the clinical benefit observed in sham-controlled fSWT trials, suggesting the benefit is not due to placebo alone. The benefit seen in both the fSWT and rWT group in our study is strikingly similar. Long-term efficacy was not assessed as most patients were an out-of-town referral population. The usage of PDE5i is a potential confounding factor that limits the ability to draw conclusions about efficacy of SWT as a stand-alone treatment. However, 8/24 (33%) and 9/24 (37.5%) of men treated with rWT and fSWT, respectively, reported grade 3 improvement not requiring use of PDE5i after SWT, suggesting the independent efficacy of both SWT modalities in a sizable minority of men. Additionally, PDE5i use after SWT is commonly performed in clinical practice, and SWT may enhance the therapeutic effects of PDE5i in a synergistic manner.[9]

In our patient population, low intensity SWT with either radial waves or focused shockwaves were clinically beneficial for men with a history suggestive of vasculogenic ED. Similar results were found between the two treatment modalities in our study; however, further studies with larger samples are needed to confirm our results before any recommendations on this topic are made. While limited by its retrospective nature, lack of randomization (although neither patient nor doctor had a choice of therapy) and lack of sham control, this suggests rWT is equally efficacious to fSWT in the treatment of vasculogenic ED and warrants further investigation in clinical trials.

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