(030) LOW INTENSITY SHOCKWAVE TREATMENT OF THE ERECT PENIS USING AN AIR REFLECTOR
Authors: Goldstein I , Goldstein S , Kim NN , Theuer E , Warlick J , Hopfenzitz N 
Published: December 2024

Abstract

Introduction
Low intensity shockwave treatment (LiSWT) for ED induces mechanotransduction, expansion and contraction of erectile tissue, that actively converts mechanical stimuli into biochemical signals. In animal studies, LiSWT increases density of endogenous mesenchymal stem cells, cavernosal smooth muscle synthesis, and release of vasodilating factors such as nitric oxide. Maximizing shockwave energy absorption in erectile tissue will maximize beneficial mechanotransduction effects. This cannot, however, be achieved solely by raising energy flux density and number of shocks delivered, as this strategy is associated with aversive pain. We previously used a Finite Element Method (FEM) simulation model to mathematically calculate damping and deflection during flaccid versus erect penile shockwave, demonstrating that shockwave energy absorption in erectile tissue is increased by performing erect LiSWT. This is due, in part, to penile erection being associated with increased: i) intracavernosal pressure, ii) impedance mismatch at blood-tissue interface, and iii) scatter, refraction, and diffraction effects due to more red blood cells and larger lacunar spaces compared to the flaccid penis. To amplify shockwave energy absorption in erectile tissue and therefore improve clinical outcome in our patients, we performed LiSWT during sustained grade 3-4/4 pharmacologic erection using an air reflector to maximize mechanotransduction.

Objective
To assess improvement in erectile function after erect penile shockwave with air reflector.

Methods
A retrospective chart review of penile grayscale/color Doppler (Aixplorer) ultrasound (G/DUS) parameters pre-and post LiSWT (Softwave TRT/Urogold 100 MTS) was performed in men with ED. In the erect state, multiple axial baseline grayscale images were taken at the proximal, midshaft, distal shaft and right/left crural regions of the penis. In the erect shaft, right/left sagittal planes, baseline cavernosal artery peak systolic velocity (PSV) and end diastolic velocity (EDV) values were obtained. ED patients subsequently underwent 5 erect penile LiSWT treatments over varying intervals. After sustained pharmacologic erection, 800 shocks (energy flux density 0.13 mJ/mm2, 3 Hz, membrane pressure 3), were applied each to the dorsal and ventral shaft using an air reflector placed against the opposite side of the shaft. 800 shocks were then applied to the right/left crura. Patient Global Impression of Improvement (PGI-I) was scored at each repeat visit. Approximately 2-3 months after the last treatment, penile G/DUS was repeated. Baseline and post-treatment grayscale images were analyzed by Image J, a computer-based imaging tool, to assess erectile tissue inhomogeneity, recording percent hypo-echoic area. PGI-I scores were correlated to ultrasound findings.

Results
59 patients (mean age 47 ± 23) met inclusion criteria. 37/59 (63%) had improved erectile tissue homogeneity post-LiSWT, 14/59 (24%) were unchanged, 8/59 (14%) worsened. 31/59 (53%) had PSV increase and 43/59 (73%) had EDV decrease, both markers of higher quality erectile function. Of patients with improved G/DUS findings, 25/37 (68%) rated PGI-I as very much better, much better, and a little better.

Conclusions
We present the first LiSWT clinical study performed during penile erection. We believe that maximizing erectile tissue energy absorption and therefore LiSWT-induced mechanotransduction in men with ED can be best achieved by performing LiSWT during a sustained pharmacologic penile erection with an air reflector.

Disclosure
Any of the authors act as a consultant, employee or shareholder of an industry for: TRT, MTS.