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

Abstract and Introduction

Abstract

Background: Low-intensity shockwave therapy (SWT) is an emerging treatment for erectile dysfunction (ED). Devices used for SWT include focused shockwave therapy (fSWT) or radial wave therapy (rWT), which differ in how the waves are generated, their tissue penetration, and the shape of their pressure waves. Most studies of SWT for ED to date have utilized fSWT. Although widely used, the efficacy of rWT for ED is unknown. Our objective is to compare the efficacy of rWT and fSWT for ED at our institution.

Methods: A retrospective chart review was performed to identify all men with ED treated by fSWT or rWT. Men with history suggesting non-vasculogenic ED were excluded. All men received 6 consecutive weekly treatments. The fSWT group received 3,000 shocks per treatment at 0.09 mJ/mm2. The rWT group received 10,000 shocks per treatment at 90 mJ and 15 Hz. Pre-treatment and 6-week post-treatment Sexual Health Inventory in Men (SHIM) scores were measured. Treatment response was categorized on a scale of 1–3 (1 if no improvement, 2 if erections sufficient for intercourse with phosphodiesterase 5 inhibitors (PDE5i), or 3 if sufficient erections without PDE5i). Primary endpoint was self-reported improvement score of 2 or greater.

Results: A total of 48 men were included: 24 treated by fSWT and 24 by rWT. There were no significant differences in age, duration of ED, pre-treatment PDE5i use, or pre-treatment SHIM scores between the groups. Following treatment with rWT, the mean SHIM score improved from 9.3 to 16.1 (P<0.001). The mean SHIM following fSWT improved from 9.3 to 15.5 (P<0.001). The mean improvement in SHIM score did not differ between rWT (6.8) and fSWT (6.2) (P=0.42). 54% of men treated by fSWT experienced a significant clinical improvement (≥ grade 2 response) compared to 75% in the rWT group (P=0.42). There were no reported side effects with either device.

Conclusions: In our patient population, both fSWT and rWT were moderately effective treatments for arteriogenic ED with no observable difference in efficacy between the two modalities.

Introduction

Low intensity shockwave therapy (SWT) is an emerging treatment option for men with vasculogenic erectile dysfunction (ED). The efficacy of SWT in this setting has been evaluated in several randomized trials with varying benefit.[1–7] While there is substantial heterogeneity in treatment regimens employed and the devices used, meta-analyses of these trials suggest men with vasculogenic ED experience a significant improvement in erectile function after SWT.[8–11] To date, all pre-clinical and clinical trials thus far have utilized focused shockwave therapy (fSWT).[12] Radial wave therapy (rWT) is an alternative method of creating acoustic waves that is commonly utilized in orthopedics, physical therapy, and dermatology, but has not been evaluated for use in men with ED.[13–16] The effect of rWT on men with vasculogenic ED, while often marketed as evidence-based ED treatment modality, is unknown.

Extracorporeal shockwaves used in medicine entail an acoustic wave of energy that travels through tissues and releases a rapid rise and fall of pressure at tissue interfaces, known as a shockwave. Acoustic waves can be delivered to tissues by two distinct mechanisms: focused shockwaves and non-focused radial waves. The two types of shockwaves differ substantially in their depth of tissue penetration, ability to focus the shockwave, and the rapidity of the rise and fall of pressure (shape of the shockwave). The different waveforms may produce varying biological effects, but these differences for specific indications remain largely unknown.

Focused shockwaves, which are the shockwaves used for extracorporeal shockwave lithotripsy treatment of urolithiasis, can be targeted to focal points at various tissue depths (up to 10–12 cm) by utilizing reflection of energy created by an acoustic wave source such that the waves convene at a focus point for maximal energy, limiting energy dispersion and collateral damage to adjacent tissues.[17] The energy profile of a focused shockwave entails a rapid (10 nanoseconds) rise and fall of the pressure wave. Focused shockwaves are generated by initiating a pressure wave via three distinct mechanisms: piezoelectric, electromagnetic, and electrohydraulic. These create a unique pressure wave that can be directed at a focal point.[18] fSWT devices are currently FDA class II devices, which limits use to physicians typically in IRB-approved research protocols.

In contrast, the maximal point of energy of a radial wave, sometimes referred to as a dispersive shockwave, is at the tip of the device.[19] These acoustic waves then disperse radially away from the tip of the device with rapid energy attenuation. The depth of penetration of radial waves varies based on energy input, but can reach up to 3.5 cm in human tissues. The energy profile entails a slower (5–10 microseconds) rise and fall of pressure than a focused shockwave. Radial waves are generated by a mechanical concussion in which a ballistic projectile repeatedly strikes an endplate and generates the dispersive acoustic wave. There are two mechanisms used to force the bullet against the endplate: pneumatic air compression and an electromagnetic system. rWT devices are currently FDA class I devices that do not require regulatory approval and may be used by anyone, with or without medical training.

At our clinic we have used both types of machines for clinical trials and also offer therapy outside of these trials based on a clinical diagnosis of vasculogenic ED. The objective of this study is to compare the effectiveness of rWT and fSWT on ED. We hypothesize that rWT is non-inferior to fSWT for treatment of ED. We present the following article in accordance with the STROBE reporting checklist (available at http://dx.doi.org/10.21037/tau-20-911).

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